Front Cover
 Title Page
 Front Matter
 Award of honorary memberships
 List of members
 Table of Contents
 President's address
 Partial mobilization and the Florida...
 Citrus Section
 Vegetable Section
 Processing Section
 Ornamental Section
 Krome Memorial Institute
 Report of the Executive Commit...

Title: Proceedings of the ... annual meeting of the Florida State Horticultural Society
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00053736/00001
 Material Information
Title: Proceedings of the ... annual meeting of the Florida State Horticultural Society
Uniform Title: Proceedings of the ... annual meeting of the Florida State Horticultural Society (1892)
Alternate Title: Transactions of the Florida State Horticultural Society for ..
Proceedings of the Florida State Horticultural Society for ..
Physical Description: 59 v. : ill., ports. ; 23 cm.
Language: English
Creator: Florida State Horticultural Society -- Meeting
Publisher: The Society
Place of Publication: Florida?
Publication Date: 1892-1950
Frequency: annual
Subject: Gardening -- Societies, etc   ( lcsh )
Gardening -- Florida   ( lcsh )
Genre: conference publication   ( marcgt )
Dates or Sequential Designation: 5th (May 3rd, 4th, and 5th, 1892)-63rd (Oct. 31, Nov. 1 and 2, 1950).
Numbering Peculiarities: Proceedings for the first four meetings not published.
General Note: Title from cover.
Funding: Florida Historical Agriculture and Rural Life
 Record Information
Bibliographic ID: UF00053736
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 18435967
lccn - ca 09001702
 Related Items
Succeeded by: Annual meeting of the Florida State Horticultural Society

Table of Contents
    Front Cover
        Page I
        Page II
    Title Page
        Page III
    Front Matter
        Page IV
        Page V
        Page VII
        Page VIII
    Award of honorary memberships
        Page IX
        Page X
    List of members
        Page XI
        Page XII
        Page XIII
        Page XIV
        Page XV
        Page XVI
        Page XVII
        Page XVIII
        Page XIX
    Table of Contents
        Page XX
        Page XXI
        Page XXII
        Page XXIII
    President's address
        Page 1
        Page 2
    Partial mobilization and the Florida fruit and vegetable industry
        Page 3
        Page 4
        Page 5
        Page 6
    Citrus Section
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
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        Page 84
        Page 85
        Page 86
        Page 87
        Page 88
    Vegetable Section
        Page 89
        Page 90
        Page 91
        Page 92
        Page 93
        Page 94
        Page 95
        Page 96
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        Page 128
        Page 129
        Page 130
        Page 131
        Page 132
        Page 133
        Page 134
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        Page 137
        Page 138
        Page 139
        Page 140
        Page 141
        Page 142
        Page 143
        Page 144
        Page 145
    Processing Section
        Page 147
        Page 148
        Page 149
        Page 150
        Page 151
        Page 152
        Page 153
        Page 154
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        Page 172
        Page 173
        Page 174
        Page 175
        Page 176
        Page 177
        Page 178
    Ornamental Section
        Page 179
        Page 180
        Page 181
        Page 182
        Page 183
        Page 184
        Page 185
        Page 186
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        Page 202
        Page 203
        Page 204
        Page 205
        Page 206
        Page 207
        Page 208
    Krome Memorial Institute
        Page 209
        Page 210
        Page 211
        Page 212
        Page 213
        Page 214
        Page 215
        Page 216
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        Page 268
    Report of the Executive Committee
        Page 269
        Page 270
        Page 271
        Page 272
        Page 273
Full Text


of rthe






of the


4mwad Meetinf

of the


held at

October 31, November 1 and 2


Published by The Society




OfficeS 4 f 950


Lake Wales




Lake Alfred


W. L. TAIT, Winter Haven


DR. F. S. JAMISON, Gainesville

DR. J. R. BECKENBACH, Chairman, Bradenton GEORGE H. COOPER, Princeton
R. S. EDSALL, Vero Beach E. V. FAIRCLOTH, West Palm Beach
DR. F. E. GARDNER, Orlando FRANK L. HOLLAND, Winter Haven
H. A. THULLBERY, Lake Wales




CQice.d ja f 195f


Winter Haven

West Palm Beach

Coral Gables


Winter Haven


W. L. TAIT, Winter Haven

LEM P. Woons, Tampa

DR. F. S. JAMISON, Gainesville

KINGSWOOD SPROTT, Chairman, Lake Wales FRANK L. HOLLAND, Winter Haven
R. S. EDSALL, Vero Beach DR. RALPH L. MILLER, Plymouth
E. V. FAIRCLOTH, West Palm Beach WILLARD D. MILLER, Ruskin
H. A. THULLBERY, Lake Wales



Article 1. This organization shall be
known as the Florida State Horticultural
Society, and its object shall be the ad-
vancement of Horticulture.
Article 2. Any person or firm may
become an annual member of the Society
by subscribing to the Constitution and
paying four dollars. Any person or
firm may become a perennial member of
the Society by subscribing to the, Con-
stitution and paying the annual dues for
five or more years in advance. Any per-
son or firm may become an annual sus-
staining member of the Society by sub-
scribing to the Constitution and paying
ten dollars. Any person may become a
life member of the Society by subscribing
to the Constitution and paying one hun-
dred dollars. Any person or firm may
become a patron of the Society by sub-
scribing to the Constitution and paying
one hundred dollars.

Article 3. Its officers shall consist of
a President, one Vice President for each
section, Secretary, Treasurer, Assistant
Secretaries, and Executive Committee of
seven, who shall be elected by ballot at
each annual meeting. These officers
shall take their positions immediately
following their election. The duties of
the Assistant Secretaries shall be out-
lined and supervised by the Executive
Article 4. The regular annual meet-
ing of this Society shall be held on the
second Tuesday in April, except when
ordered by the Executive Committee.

Article 5. The duties of the Presi-
dent, Vice Presidents, Secretary and
Treasurer shall be such as usually de-
volve on these officers. The President,
Secretary and Treasurer shall be ex-
officio members of the Executive Com-

Article 6. The Executive Committee
shall have authority to act for the Society
between annual meetings.
Article 7. The Constitution may be
amended by a vote of two-thirds of the
members present.
Article 8. A section of the annual pro-
gram of the Society shall be devoted to
the discussion of sub-tropical fruits, ex-
clusive of the commonly grown varieties
of citrus fruits. This section shall be
known as the Krome Memorial Institute.
It shall be presided over by a fourth vice
president who shall be elected by ballot at
each annual meeting of the members in
attendance at the Institute. The fourth
vice president shall be an ex-officio mem-
ber of the Executive Committee.
Article 9. The Executive Committee
may, at its discretion and on the basis of
merit, nominate not to exceed five per-
sons in any one year, for Honorary Mem-
bership in the Society. Honorary mem-
bers shall enjoy all privileges of the
Article 10. A section of the annual
program of the Society shall be devoted
to the discussion of vegetables and other
truck crops. This section shall be known
as the Vegetable Section of the Florida
State Horticultural Society. It shall be
presided over by a Vice President, who
shall be elected at each annual'meeting
of the Society by the members in attend-
ance at the Session. The Vice President
shall be an ex-officio member of the
Executive Committee.
Article 11. A section of the annual
program of the Society shall be devoted
to the discussion of ornamentals. This
section shall be known as the Ornamental
Section of the Florida State Horticultural
Society. It shall be presided over by a
Vice President, who shall be elected at


each annual meeting of the Society by
the members in attendance at the Ses-
sion. The Vice President shall be an
ex-officio member of the Executive Com-

Article 12. A section of the annual
program of the Society shall be devoted
to the discussion of processing. This

section shall be known as the Processing
Section of the Florida State Horticultural
Society. It shall be presided over by a
Vice President, who shall be elected at
each annual meeting of the Society by
the members in attendance at the Ses-
sion. The Vice President shall be an
ex-officio member of the Executive Com-


1. The Society year shall be coexten-
sive with the calendar year, and the an-
nual dues of members shall be four

2. All bills authorized by the Society
or its Executive Committee, for its legi-
timate expenses, shall be paid by the Sec-
retary's draft on the Treasurer, O.K'd
by the President.

3. The meetings of the Society shall be
devoted only to Horticultural topics, from
scientific and practical standpoints, and
the presiding officer shall rule out of
order all motions, resolutions and discus-
sions tending to commit the Society to
partisan politics or mercantile ventures.

4. All patron and life membership dues
and all donations, unless otherwise speci-
fied by donor, shall be invested by the
Treasurer in United States Government
bonds. The earnings from these bonds
shall be left as accrued values or rein-
vested in United States Government
bonds of a guaranteed periodical value
unless it is ordered by the Executive
Committee or the Society that such earn-
ings can be made available for operating
expense. Receipts from perennial mem-
bership dues shall be placed on deposit at
interest by the Treasurer. Only three
dollars ($3.00) from each perennial mem-
bership fee shall be available during any
calendar year for payment of operating
expenses of the Society.



of Lakeland, Fla., born in Batesburg,
South Carolina, February 11, 1894;
graduate of Lakeland High School and
of the College of Law of the University
of Florida, receiving LL.B. degree; Doc-
tor of Humanities, Fla. Southern Col-
lege; admitted to the Bar in 1914; in his
early practice, specialized in Municipal
Law. He served several terms as Chair-
man of the Legislative Committee of the
Florida League of Municipalities; special
counsel for the Department of Agricul-
ture, State of Florida; served in the
Navy during World War I. He was
elected to the Congress on November 8,
1932; reelected continuously up to and
including the present Congress; volun-
tarily retiring on January 1, 1951.
During his happy and productive rep-
resentation of Florida in the Congress,
Mr. Peterson has developed, and shown
repeatedly, not only a keen interest in
horticulture and other important inter-
ests, but a profound knowledge of them.
This knowledge, coupled with his earnest
desire to be of worthwhile public service,
has been a tremendous profit to horticul-
ture on many occasions. He has been an
active citrus grower in Florida for many
years. Known widely as the outstanding
committee worker in the Congress, his
work as a Member and Chairman of the
Public Lands Committee has meant much
to this country in dealing with public
lands and natural resources. Mr. Peter-
son has served horticulture and other in-
terests of Florida with real distinction.

DR. AVERY S. HOYT was born in
San Diego, California, on September 16,
1888. He was graduated from Pomona
College, California, in 1910 with a BSA
degree. Following his graduation he en-
tered the employ of the California State

Department of Agriculture, and was as-
signed to plant quarantine enforcement
activities. He occupied various positions
of responsibility within that organiza-
tion, and in 1928 he was appointed Di-
In 1931, he went to Washington to be-
come Assistant Chief of the Plant Quar-
antine and Control Administration. In
1934, he was selected to serve as Assist-
ant Chief of the newly created Bureau of
Entomology and Plant Quarantine. By
reason of meritorious service he was ad-
vanced to the position of Associate Chief
in 1941. On April 12, 1950, he was made
Chief of the Bureau of Entomology and
Plant Quarantine to fill the vacancy
brought about by the death of Dr. P. N.
Dr. Hoyt's contributions to the agri-
culture of the nation have been largely
in the field of plant quarantine. His early
experiences in California convinced him
of the need for taking all possible action
to protect the several states from insects
and disease from abroad, particularly
states like California, Texas, Florida,
and others which are peculiarly exposed
to invasion by reason of geographical
locations and international travel and
trade. Throughout his service as a fed-
eral official he has endeavored to pro-
vide this protection while adhering to a
strict scientific basis for all of his official
actions, in spite of pressure brought to
bear from many sources.

DR. HAROLD MOWRY came to Flor-
ida in 1916 from Kansas and Colorado.
During the ensuing thirty-four years his
record of significant contributions to our
horticultural industry has not only added
millions of dollars to the income of our
State, but through his zeal, his complete-
ly unselfish and devoted service, his


loyalty to high ideals, and his friendly
and sincere manner, he has carved for
himself a place in the hearts of the mem-
bers of this Society.
His numerous scientific contributions
are widely recognized. With the Florida
State Plant Board he contributed to the
eradication of Citrus Canker and the
Mediterranean Fruit Fly. With the Flor-
ida Agricultural Experiment Station his
original research pointed the way to the
important role of the minor elements in
plant nutrition on the mineral soils of
the State. He is an undisputed authority
on the culture and botany of Florida's
ornamental trees and shrubs, and of
many of her fruits. His careful experi-
ments became the foundation on which
our Tung industry developed. While with
the Experiment Station, he was author
of thirteen of its most widely read bulle-
tins, and has written hundreds of arti-

cles for scientific and popular journals.
In addition, he has written thousands
of letters to individuals, helping in the
solution of their horticultural problems,
not only in Florida, but all over the
He retired on January 31, 1950 as
Director of the University of Florida
Agricultural Experiment Station, to
which position he advanced through the
ranks from Assistant Horticulturist. As
Director his ability resulted in the
growth of his organization to a position
where it is now one of the largest in the
Nation, with a world-wide reputation
for the high standards and productivity
of its research.
With all this he has remained a modest
man and a loyal friend. He is deserving
of the highest honor that this Society
can confer.




Fairchild, Dr. David, Coconut Grove
Haden, Mrs. Florence P., Coconut Grove
Hastings, H. C., Atlanta, Georgia
Henricksen, H. C., Eustis
Holland, Spessard L., Bartow
Hoyt, Dr. Avery S., Wasington, D. C.
Hume, Dr. H. Harold, Gainesville

Lipsey, L. W., Blanton
Mayo, Nathan, Tallahassee
Mowry, Dr. Harold, Gainesville
Peterson, J. Hardin, Lakeland
Robinson, T. Ralph, Terra Ceia
Swingle, Dr. W. T., Washington, D. C.


American Agricultural Chemical Company, Pierce
American Fruit Growers, Inc., Maitland
Angebilt Hotel, Orlando
Armour Fertilizer Works, Jacksonville
Buckeye Nurseries
Chase & Company, Sanford
Deerfield Groves, Wabasso
Deering, Charles
Exchange Supply Company, Tampa
Exotic Gardens, Miami
Florida Citrus Exchange, Tampa
Florida East Coast Hotel Co., St. Augustine
Florida Grower Publishing Co., Tampa
The Fruitlands Co., Lake Alfred
Gardner, F. C., Lake Alfred
'Glen St. Marys Nurseries Co., Glen St. Marys
Gulf Fertilizer Co., Tampa

Hastings, H. G. Co., Atlanta, Georgia
Hillsboro Hotel, Tampa
Klemm, A. M. & Son, Winter Haven
Lake Garfield Nurseries, Bartow
Manatee Fruit Company, Palmetto
Mills The Florist, Jacksonville
Nocatee Fruit Co.. Nocatee
Oklawaha Nurseries Co., Inc., Lake Jem
Southern Crate Manufacturing Assn.
Stead, Lindsay, Box 809, Ft. Pierce
Thomas Advertising Service
U. S. Phosphoric Products, Division Tennessee Corp.,
61 N. Broadway, New York, N. Y.
U. S. Phosphoric Products, Division Tennessee Corp.,
Box 8269, Tampa
Van Fleet Co., Winter Haven
Wilson & Toomer Fertilizer Co., Jacksonville


Agricultural Experiment Station, Puerto Rico
Albertson Public Library, Orlando
Allenbrand, Alfred, Box 288, Frostproof
Alderman, A. D., Bartow
Andrews, C. W., John Crerar Library, Chicago, Illinois
Barber, C. F., Macclenny
Bartlum, W. Leonard, Florida Agricultural Supply Co.,
Berger, Mrs. E. W., Gainesville
Bouis, Clarence G., Box 6, Ft. Meade
Bringham, M. S., Micco
Britt, John F., Ft. Pierce
Brown, A. C., Gainesville
Bullard, Henry F., Bullard & Sprott, Lake Wales
Carnegie, Mrs. T. M., Fernandina
Champlain, A. E., R 3, No. 1, Palmetto
Chidester, D. D.. 446 Painter Ave., Whittier, California
Christiancy, Cornelius, Port Orange
Clement, Waldo P., Georgiana
Conner, Wayne E., New Smyrna
Cook, R. F., Leesburg
County Agent, Orange County, Orlando
Crutchfield & Woolfolk, Pennsylvania Produce Bldg.,
Pittsburgh, Pennsylvania
Dunedin Public Library, Dunedin

Ellsworth, Wilma J. (Miss), Rt. No. 1, Dade City
Fairchild, Dr. David, Coconut Grove
Fugazzi, John, Fugazzi Brothers, Clearwater
Gifford, Dr. John, Coconut Grove
Guest, Mrs. Amy, N. Ocean Blvd., Palm Beach
Haden, Mrs. Florence P., Coconut Grove
Hakes, L. A., Box 771, Orlando
Hastings, H. G., 16 W. Mitchell St., Atlanta, Georgia
Henricksen, H. C., Box 1045, Eustis
Hernandez, Pedro, 108 Cienfuegos, San Fernando, Cuba
Hollingsworth, G. S., Arcadia
Hume, H. Harold, Gainesville
Iowa State College Library, Ames, Iowa
Jacocks, A. J., Winter Haven
Lassen, H. C., Garden Spring Terrace,
Saratoga, California
Lauman, G. N., Ithaca, N. Y.
Leonard, George V., Hastings
Manatee Frtit Co., 1st National Bank Bldg., Tampa
Martin, A. Wm., Box 36, Sebastian
Mathews, E. L., Plymouth
McCarty, B. K., Eldred
McCarty, Mrs. C. T., Eldred
Merritt, Dr. J. C., 297 Sherman St., St. Paul Minnesota
Michael, A. B., Wabasso


Montgomery, Robert H. (Col.), Coconut Grove
Montgomery, Mrs. Robert H., Coconut Grove
Morrell, Albert, Orlando
Mountain Lake Corporation, Lake Wales
O'Byrne, Frank M., Lake Wales
Ohmer, C. J., West Palm Beach
Olivebaum, J. E., Clermont
Pedersen, W. L., Winter Haven
Pennock, Henry, Sr., Jupiter
Phillips, Howard, Orlando
Phipps, John S., N. Ocean Blvd., Palm Beach
Phipps, H. C., N. Ocean Blvd., Palm Beach
Phipps, Howard, Delray Beach
Pike, W. N., Blanton
Plymouth Citrus Growers Assn., Plymouth
Prosser, Lew, Plant City
Raulerson, J. Ed, Arcadia
Reasoner, N. A., Bradenton
Reid, W. C., Largo
Rohde, H., Sebring
Ricketson, Mrs. M. C., "Grayfield," Fernandina
Sample, J. W., Haines City

Sandlin, A. R., Leesburg
Schuman, Albert, Sebastian
Sellards, Dr. E. H., State Geologist, Austin, Texas
Sevil, Mrs. Sara L., Fort Myers
Sloan, G. D., Box 1021, Tampa
Stanton, F. W., Dock & Walnut Sts., Philadelphia,
Stead, Lindsay, Box 809, Ft. Pierce
Stevens, Edmund, Verge Alta, Puerto Rico
Stuart, L. E., Montemorelos, Mexico
Taber, Mrs. George L., Glen St. Marys
Taylor, J. S., Largo
Thomas, Jefferson, Gainesville
Todd, E. G., Avon Park
Towns, Thomas R., Holguin, Cuba
Trelease, Wm., University of Illinois, Urbana, Illinois
Trueman, Roy B., Trueman Fertilizer Company,
Von Borowsky, Miss Lisa, Brooksville
Wilson & Toomer Fertilizer Co., Box 4459, Jacksonville
Wirt, E. L., Box 144, Babson Park
Others, W. W., 457 Boone St., Orlando


Adams Packing Assn., Inc., Box Drawer "B,"
Allen, Ruth Stuart, P. O. Box 804 (Tropical
Gardening), Coral Gables
American Cyanamid Company, 30 Rockefeller Plaza,
New York 20, N. Y.
American Fruit Growers, Inc., Ft. Pierce
Austin, Guy D., and Co., Miami 35
Babb, Herbert A., Gulf Fertilizer Co., Umatilla
Barber, Bascom D., Wilson & Toomer Fertilizer Co.,
Box 685, Clearwater
Bellows, Dr. J. M., Hector Supply Co., Miami
Bergstrom Trading Company, Inc., 233 Broadway,
New York 7, N. Y.
Bland, W. T., American Fruit Growers, Lake Jem
Brady, R. C., NACO Fertilizer Co., Titusville
Brooks, J. R. Box 36, Homestead
Broward Grain and Supply Co., Inc., Ft. Lauderdale
Browder, David, Box 310, Arcadia
Bryan, L. T., Fosgate Growers Coop., Box 2673,
Burpee, W. Atlee Co., Sanford
Burrichter, A., Box 42, Homestead
California Spray Chemical Co., Box 1231, Orlando
Campbell, John W., Goulds
Carleton, R. T., Plymouth
Cartledge, Raymond H., Cartledge Fertilizer Co.,
Charles, Wilber G., Florence Citrus Growers Assn.,
Florence Villa
Chase, Randall, Box 291, Sanford
Clask, Everett B., Associated Seed Growers, Inc.,
Walcaid Bldg., Bradenton
Clark, John D., Waverly
Clark, S. W., Agricultural Department, Texas Gulf
Sulphur Co., 1002 Second National Bank
Bldg., Houston 2, Texas
Clinton Foods., Inc., Dunedin
Conkling, W. Donald, Citrus Culture Corp., Mt. Dora
Cooper, George H., Glade & Grove Supply Co., Box
198, Princeton

Cooper, R. K., Florence Foods Inc., Florence Villa
Crum, H. M., International Minerals & Chemical Corp.,
908 Mortgage Guarantee Bldg., Atlanta 3, Ga.
Dabney, B. G., Coronet Phosphate Co., Plant City
Dancy, R. C., Jackson Grain Co., Cass & Ashley Sts.,
DiGiorgio Fruit Corp., Winter Haven
Dixie Lime Products Co., Box 578, Ocala
Dolomite Products Inc., Box 578, Ocala
Dozier, G. L., NACO Fertilizer Co., Box 232, McIntosh
Duda, Andrea, Jr., A. Duda & Sons, Oviedo
Duda, Ferdinand, A. Duda & Sons, Oviedo
Dundee Citrus Growers Assn., Dundee
Dye, Alfred M., Everglades Fertilizer Co., Box 821,
Ft. Lauderdale
Dye, John B., Jr., Everglades Fertilizer Co., Box 821,
Ft. Lauderdale
Edsall, R. S., 1828-28th Ave., Vero Beach
Faircloth, E. V., 2829 South Dixie, West Palm Beach
Faircloth Truck-Tractor Co., 2829 South Dixie, West
Palm Beach
Florida Agricultural Research Institute, Box 392,
Winter Haven
Florida Citrus Canners Coop., Lake Wales
Florida Citrus Exchange, Box 2349, Tampa 1
Florida Citrus Production Credit Assn., Box 2111,
Florida Dolomite Co., Pembroke
Florida Fruit & Vegetable Assn., 29 South Court St.,
Florida Seed and Feed Co., Ocala
Fortner, J. E., Citrus Culture Corp., Mt. Dora
Fudge, Dr. B. R., Wilson & Toomer Fertilizer Co.,
P. O. Drawer 4459, Jacksonville
Grant, A. J., 259 Scotland St., Dunedin
Green, William F., Wilson & Toomer Fertilizer Co.,
P. O. Drawer 4459, Jacksonville
Greenwood Products Co., Graceville
Growers Fertilizer Coop., Lake Alfred
Hagadorn, D L., Jackson Grain Co., Cass & Ashley
Sts., Tampa


Hagar, Jack, Fosgate Growers Coop., Box 2672,
Haines City Citrus Growers Assn., Haines City
Haines City Heights, Inc., Haines City
Hawkins, Howard, Box 410, St. Augustine
Heller Brothers Packing Co., Winter Garden
Henderson, Fred F., Winter Haven
Hicks, W. B., Wilson & Toomer Fertilizer Co.,
P. O. Drawer 4459, Jacksonville
Hinson, Alvin H., Box 868, Plant City
Holland, Frank L., 324 Ave. B., NE, Winter Haven
Horton, W. D., Collins Feed & Supply Co., N. E. 94th
& FEC R'way, Miami 38
Howard, J. D., Howard Fertilizer Co., Orlando
Howard, R. M., Howard Fertilizer Co., Orlando
Howell, Morton, Waverly Growers Coop., Waverly
Hunt, D. A., Florida Citrus Canners Coop., Lake Wales
Immokalee Growers, Inc., c/o J. T. Gaunt, Immokalee
Jackson, R. D., Jackson Grain Co., Cass & Ashley Sts.,
Jamison, J. R., Deerfield Groves Co., Wabasso
Jones, R. S., Wilson & Toomer Fertilizer Co., P. O.
Drawer 4459, Jacksonville
Jungle Gardens, Sarasota
Kime, C. D., Jr., Waverly Growers Coop., Waverly
Kinnard, R. R., Gulf Fertilizer Co., Box 607, Homestead
King, Battey, Naples
Kinsey, L. P., Box 878, Winter Haven
Kirtley, A. G., Dundee Citrus Growers Assn., Box
1121, Winter Haven
Klee, W. H., NACO Fertilizer Co., Jacksonville 1
Klemm, A. M. & Son, Winter Haven
Laird, Norman N., Waverly Growers Coop, Waverly
Lake County Citrus Sales., c/o Bruce Floyd, Leesburg
Lee, C. S., Box 225, Oviedo
Lesley, John T., Haines City Citrus Growers Assn.,
Haines City
Lins, E. W., American Fruit Growers, Inc., Fee Bldg.,
Ft. Pierce
Little, C. S., Superior Fertilizer Co., Odessa
Lucas, Glen H., Peninsular Fertilizer Co., Box 2989,
Tampa 1
MacDonald, R. M., Chester Groves Co., City Point
McLain, L. Rogers, Gulf Fertilizer Co., Box 2721,
Tampa 1
McLane, W. F., Lyons Fertilizer Co., Box 310, Tampa
McSweeney, W. M., Gulf Fertilizer Co., Box 2721,
Tampa 1
Marrs, G. F., Superior Fertilizer Co., 914'2 McBerry,
Matheson, Hugh M., 418 S. W. 2nd Ave., Miami 36
Mathias, A. F., Superior Fertilizer Co., Box 183,
Lake Hamilton
Maughan, D. B., California Spray-Chemical Co.,
Maxwell, Lewis, Jackson Grain Co., Cass & Ashley
Sts., Tampa
Maxcy L., Inc., Frostproof
Mershon, Claud C., Fosgate Growers Coop., Box 2673,
Messec, Murrel, Gulf Fertilizer Co., Box 687,
Michael, A. B., Deerfield Groves Co., Wabasso
Mitchell, Edward C., Citrus Culture Corp., Mt. Dora
Mount Dora Growers Coop., Mount Dora
Oslo Citrus Growers Assn., Oslo
Palm Harbor Citrus Growers Assn., Palm Harbor

Pasco Packing Co., Dade City
Pedersen, W. C., Waverly Growers Coop., Waverly
Perrin & Thompson, Inc., Box 1000, Winter Haven
Pinellas Growers Assn., Clearwater
Pinkerton, J. B., Chester Groves Co., City Point
Plummer, Dr. J. K., Tenn. Corp. Research Lab., 900
Roosevelt Hwy., College Park, Ga.
Plymouth Citrus Growers Assn., Plymouth
Prevatt, J. B., Lake Region Pkg. Assn., Tavares
Price, R. C., Florida Agri. Supply Co., Box 658,
Jacksonville 1
Prine, Henry A., Domino Citrus Assn., Inc., Box 179,
Prine, R. H., Box 85, Terra Ceia
Producers Supply, Inc., Palmetto
Raoul, Loring, Box 871, Sarasota
Reed, R. R., Gulf Fertilizer Co., P. O. Box 2721,
Richardson, D. K., 2664 19th St., Vero Beach
Richardson, E. G., 235 S. Indian River Drive,
Ft. Pierce
Rickborn, J. H., Lyons Fertilizer Co., Box 310,
Roess, M. J., Box 388, Jacksonville
Rothwell, A. D., Superior Fertilizer Co., 1407
Hesperides, Tampa
Ruskin Vegetable Distributors, Ruskin
Ryburn, Alexander W., Box 977, Vero Beach
Sachs, Ward H., Box 3588, Orlando
Sample, James M., Lyons Fertilizer Co., Box 310,
Sarasota Jungle Nurseries, Sarasota
Seidel, G. A., Box 7, Gotha
Sheffield, J. R., Coronet Phosphate Co., 19 Rector St.,
New York 6, N. Y.
Shields, J. C., Domino Citrus Assn., Inc., Box 179,
Skinner, B. C., Dunedin
Skinner, F. L., 379 Monroe St., Dunedin
Sloan, G. Dexter, Superior Fertilizer Co., Box 1021,

Slough Grove Co., Inc., Dade City
Smith, F. M., Howard Fertilizer Co., Orlando
Smith, Herbert A., Jr., 1019 Lancaster Drive, Orlando
Snively, John A., Jr., Eloise Groves Assn., Winter
Snively, T. V., Box 10, Winter Haven
South Florida Motor Co., Box 151, Sebring
South Lake Apopka Citrus Growers Assn., Oakland
Speights, J. A., Everglades Fertilizer Co., Box 821,
Fort Lauderdale
Spencer, T. C., Haines City
Stewart Packing Coop., Box 324, Auburndale
Swann, Tom B., Box 232, Winter Haven
Tennessee Corp., Research Laboratories, 900 Roosevelt
Highway, College Park, Ga.
Thomas, Wayne, Box 831, Plant City
Thullbery, C. C., Lake Region Pkg. Assn., Tavares
Tilden, A. M., Box 797, Winter Haven
Tilden, L. W., Winter Garden
Tomelaine Groves, Winter Haven
Tucket, Inc., Minneola
Van Horn, M. C., Florida Agri. Supply Co., Box 658,
Jacksonville 1
Virginia-Carolina Chemical Corp., Orlando
Walker, Eli C., Jr., Box 796, Vero Beach
Ward's Nursery, Box 177, Avon Park


Waring, W. L., Jr., Lyons Fertilizer Co., Box 310,
Waverly Fertilizer Works, Waverly
Waverly Growers Coop., Waverly
Wetumpka Fruit Co., Box N, Hastings
Wheeler Fertilizer Co., Oviedo
Whitfield, Charles S., Amherst Apts., Orlando
Wilson, Homer A., Gulf Fertilizer Co., Box 746,
Ft. Pierce
Winter Park Land Company, 128 Park Ave. S.,
Winter Park
Wolfe, J. C., Lyons Fertilizer Co., Box 310, Tampa
Wood, Wade W., Gulf Fertilizer Co., Box 634, DeLand

Woodlea Groves, Box 144, Tavares
Woodruff, F. H. & Sons Inc., 695 Glenn St., S. W.,
Station A, Box 164, Atlanta, Ga.
Woods, Fred J., Gulf Fertilizer Co., Box 2721, Tampa 1
Woods, J. Albert, Wilson & Toomer Fertilizer Co.,
P. O. Drawer 4459, Jacksonville
Woods, Lem P., Gulf Fertilizer Co., Box 2721,
Tampa 1
Wray, Floyd L., Box 1782, Flamingo Groves, Inc.,
Ft. Lauderdale
Yager, Alonzo, Waverly Growers Coop., Waverly
Yandre, Thomas E., Farm & Home Machinery Inc.,
Box 8547, Orlando


As of February 26, 1951

Abbey, O. H., P. O. Box 27, Ft. Lauderdale
Abbott, Fred P., Room 105, Union Station,
Savannah, Ga.
Adams Packing Assn. Inc., Drawer B, Auburndale
Alexander, J. F., Box 154, Bartow
Alexander, Taylor R., Botany Dept. Univ. of Miami,
Allen, E. J., 2150 N. W. 17th Ave., Miami
Allison, R. V., Everglades Exp. Sta., Box 37, Belle Glade
American Cyanamid Co., 30 Rockefeller Plaza,
New York 20, N. Y.
American Fruit Grower Publishing Co.,
106 Euclid Ave., Willoughby, Ohio
American Potash & Chemical Co., Atlanta, Ga.
American Potash Institute, Am. Chemical Soc. Bldg.,
1155 16th St. N. W., Washington 6, D. C.
Andrews, W. R. E., 1505 Race St., Philadelphia 2, Pa.
Angel, L. B., Haines City
Appleton, Shelton, Box 2281, Lakeland
Armour Fertilizer Works, P. O. Box 599, Jacksonville
Arzave, Genaro, P. Mier 328 Ote., Monterey,
N. L. Mexico
Atkins, C. D., Box 443, Rt. No. 1, Winter Haven
Ayers, Ed L., County Agent, Palmetto
Backus, F. E., Box 283, Frostproof
Bailey, E. R., Sanibel
Baker, A. L., Box 247, Lakeland
Baldwin, Mrs. Porter, 308 Monroe Drive,
West Palm Beach
Ballentine, C. C., P. O. Box 3751, Orlando
Barber, B. D., Box 685, Clearwater
Barcus, David F., Box 601, Ft. Pierce
Barker, J. P., Box 1131, Winter Haven
Barksdale, D. N., Box 2567, Mulberry
Barnett, Joe P., c/o American Fruit Growers, Inc.,
Ft. Pierce
Barrus, Mrs. Edith, Tallahassee
Bartz, Paul, 306 S. E., 12th, Ft. Lauderdale
Baskin, J. L., 1230 Golden Lane, Orlando
Bass, C. A., 82 N. W. 34th St., Miami
Beardsley Farms, Clewiston
Beckenbach, J. R., Asso. Director, Fla. Agr. Exp.
Station, Gainesville
Beerhalter, A., Rt. No. 3, Box 300, Ft. Pierce
Beisel, C. G., Real Gold Citrus Products, Box 280,
Anaheim, California
Benitez, Lic, Jose, Edificio La Nacional, 311
Monterrey, N. L. Mexico

Bennett, Charles A., 1825 N. W. 21st, Miami 37
Berry, James, 332 "E" S. E., Winter Haven
Bickner, Charles, P. O. Box 1282, Bradenton
Biebel, Joseph R., 312 No. 4 Rd., S. Miami 43
Biggins, Harry N., Box 58, Clearwater
Bissett, Arthur M., Box 66, Winter Haven
Bissett, Owen, 1340 Lake Mirror Drive, Winter Haven
Blackmon, G. H., Agri. Exp. Sta., Gainesville
Bodine, E. W., 50 W. 50th St., Shell Chemical,
New York, N. Y.
Boswell, Ralph, 206 E. Amelia St., Orlando
Bourne, Dr. B. A., Box 6368, Clewiston
Boyd, F. E., Box 120, Montgomery, Ala.
Boyd, Thos. M., Rt. No. 1, Box 408, Winter Haven
Bradbury, Charles O., Rt. No. 2, Winter Haven
Bragdon, K. E., Indian River City
Bristow, J. J. R., Juice Industries, Inc., Dunedin
Brockway, E. K., Box 695, Clermont
Brokaw, C. H., Minute Maid, Plymouth
Brooks, A. N., Box 522, Lakeland
Brooks, J. H., DiGiorgio Fruit Corp., Box 1352,
Ft. Pierce
Brown, C. H., Box 601, Ft. Pierce
Brown, Glenn, Tavares
Brown, M. R., Box 575, Winter Haven
Brown, R. E., Lake Wales
Brown, R. L., NACO Fertilizer Co., Ft. Pierce
Brown, T. O., Box 96, Frostproof
Brown, Mrs. V. L. Stanford St., Bartow
Bryan, D. S., 510 S. Broadway, Bartow
Bryan, R. L., Box 154, Bartow
Buckles, W. V., P. O. Box 86, Leesburg
Bullard, Henry, Lake Wales
Burch, R. W., Inc., Plant City
Burden, George F., P. O. Box 935, Winter Haven
Burgis, Donald S., Box 678, Manatee Station, Bradenton
Burns, Theodore C., Box 308, Palmetto
Butcher, F. Gray, Univ. of Miami, Coral Gables
Cadmus, Harold J., 3817 San Pedro, Tampa 9
California Fruit Growers Exchange, Research Dept.,
616 E. Grove St., Ontario, California
Call, A. H., 13472 Burto St., Anaheim, California
Calumet & Hecla Consolidated Copper Co.,
Calumet, Mich.
Camp, Dr. A. F., Citrus Exp. Sta., Lake Alfred
Carlton, R. A., P. O. Box 1896, West Palm Beach
Casseres, Ernest H., Dept. of Veg. Crops, Cornell, Univ.,
Ithaca, N. Y.


Central Groves Cooperative, Lake Hamilton
Chandler, L. L., Goulds
Chase, Frank K., 1819 Cherokee Trail, Lakeland
Chase, Frank W., Isleworth, Windermere
Chase, Randall, Box 291, Sanford
Chase, Sydney O., Jr., P. O. Box 599, Sanford
Chipman Chemical Co., Inc., Box 809,
Bound Brooks, N. J.
Chissom, G. A., 1200 Sunshine Ave., Leesburg
Chronister, B. S., 1108 E. Main St., Richmond, Va.
Citrus Grove Development Co., Babson Park
Clayton, H. G., Hort. Bldg., Univ. of Fla., Gainesville
Clearwater Growers Assn., Box 299, Clearwater
Clements, W. B., Box 65, Leesburg
Coastes, J. L., Adams Packing Assn., Inc., Auburndale
Coe, Dr. Dana G., 1425 Providence Rd., Lakeland
Coe, Ray, Star Route, Bunnell
Coleman, K., Speed Sprayer Co., Orlando
Collins, Paul F., Haines City
Colter, R. L., Box 830, Lakeland
Commander, C. C., Box 2849, Tampa
Connell, Ed. B., Rt. No. 1, Box 502, Valrico
Connor, F. M., P. O. Box 265, Palmetto
Conover, Robert A., Sub-Tropical Exp. Sta., Homestead
Cooney, Ray H., 1007 Wallace S. Bldg., Tampa
Cooper, William C., Box 241, Weslaco, Texas
Costa, Dr. A. S., USDA, Institute Agronimico,
Campinas, Brazil
Covington, D. D., Jr., Covington Fruit Pkg. Co.,
Dade City
Cowperthwaite, W. G., Veg. Crops Lab., Box 678,
Manatee Sta., Bradenton
Crawford, Mrs. W. T., Haines City
Creighton, John T., Box 2845, Univ. Sta., Gainesville
Crenshaw-McMichael Seed Co., Box 1814, Tampa 1
Crews, Standish L., Box 179, Vero Beach
Crossman, W. F., Fla. Southern College, Pi Kappa
Alpha, Lakeland
Crumb, Frank K., Box 807, Lakeland
Crutchfield, Cecil M., Box 555, Auburndale
Curry, Kenneth, 1618 Rose Ave., Knoxville 16, Tenn.
Croce, Francisco M., Matienzo 339, San Jose,
Mendoza, Argentina
D'Albora, John V., Jr., Box 1189, Cocoa
Daly, C. F., West Coast Fert. Co., Box 1094, Tampa 1
Davis, Charles P., Box 947, Winter Haven
Day, William A., Box 29, Bradenton
Decker, Phares, Agr. Exp. Sta., Gainesville
Dekle, George W., State Plant, Gainesville
Dennison, Raymond A., Dept. of Hort., Fla. Agr. Exp.
Sta., Gainesville
D'Ercole, A., 808% Windsor St., Lakeland
Dewson, I. B., 424 Arden Court, Ridgewood, N. J.
Diamond R. Fertilizer Co., Inc., Winter Garden
Dickey, R. D., P. O. Box 2845, Univ. Sta., Gainesville
Dickman, Lyle C., Ruskin
Dickman, Paul B., Ruskin
Diem, John J., Southern Agri. Insecticides, Inc.,
Dierberger Agro-Commercial LTDA., Caixa Postal 458,
S. Paulo, Brazil
Dijkman, Dr. M. J., 4013 Douglas Rd., Coconut Grove,
Dixon, W. R., P. O. Box 144, Winter Garden
Dolan, F. M., 1817 Granada Blvd., Coral Gables
Donaldson, C. S., Avon Park
Dowdell, R. S., Box 1907, Orlando

Dowling, Paul M., 1644 E. Livingston, Orlando
Drondoski, John E., Box 1225, Ft. Pierce
Dunlap, R. C., Box 668, Hialeah
Dunne, Hugh J., San Antonio
Dye, H. W., Niagara Chem. Div., Food Machinery &
Chem. Corp., Middleport, N. Y.
Dyson, Z. V., Orlo Vista
Eaton, DeWitt, Box 142, Sarasota
Eddins, Dr. A. H., Potato Laboratory, Hastings
Edsall, R. S., 1828 28th Ave., Vero Beach
Eide, Andrew, c/o J. C. Sample, Naples
Elvin, Evert, Citrus Exp. Sta., Lake Alfred
Enzie, W. D., BirdsEye Snider Div., 40 Franklin St.,
Rochester N. Y.
Estes, H. O., Box 835, Haines City
Evans, Thomas E., Box 1105, Lake Alfred
Everglades Fertilizer Co., Ft. Lauderdale
Fascell, Michael, 1661 S. W. 22nd St., Miami
Fawsett, C. F., Jr., Box 186, Orlando
Feaster, O. O., Rt. No. 1, Box 740, Lakeland
Felton, E. R., Lakeland
Feustel, Wm. K., Rt. T. Vanderbilt Co., 280 Park
Ave., New York 17, N. Y.
Fields, Charles E., Box 532, Winter Haven
Fifield, Willard M., Agr. Exp. Sta., Gainesville
Fisher, Miss Francine E., Citrus Exp. Sta., Lake Alfred
Fitzpatrick, Thomas E., Box 572, Haines City
Fla. Chamber of Commerce, Jacksonville
Florida Geological Survey, Tallahassee
Fogg, Harry W., Box 774, Eustis
Food Machinery Corp., John Bean Div., 1812 W.
Washington St., Orlando
Ford, Dr. Harry W., Citrus Exp. Sta., Lake Alfred
Ford, Robert, 218 E. Bay St., Lakeland
Forsee, Dr. W. T., Jr., Everglades Exp. Sta.,
Belle Glade
Foy, John E., Jr., Ashcraft-Wilkinson Co., Wallace S.
Bldg., Tampa 2
Freeze, Walter, Box 2470, Clearwater
Friend Sprayer Service Corp., Frostproof
Friend, W. H., Box 548, Weslaco, Texas
Frierson, Paul E., State Plant Board, Gainesville
Frisbie, S. Lloyd, Bartow
Futch, Ivey E., Box 857, Lake Placid
Gainesville Garden Club, c/o Mrs. James W. Day,
Pres., 530 N. E. 7th Ave., Gainesville
Gallagher, Vincent, 13 N. E. 13th St., Delray Beach
Gardner, Mrs. F. C., Lake Alfred
Gardner, Dr. Frank E., 415 Parramore St., Orlando
Garrett, Charles A., RFD 1, Box 216, Kissimmee
Gates, Charles M., Univ. of Miami, Coral Gables
Gerwe, Dr. R. D., Food Mach. & Chem. Corp.,
Gill, B. R., Rt. No. 1, Ft. Lauderdale
Glass, Mrs. E. L., Haines City
Gould, Chester N., Star Rt. Box 23, West Palm Beach
Grant, Dr. Theo J., USDA, Institute Agronimico,
Campinas, Brazil
Gratz, L. O., Agr. Exp. Sta., Gainesville
Graves, Forrest C., Box 606, Vero Beach
Graves, J. R., Box 922, Vero Beach
Green, W. F., Wilson & Toomer Fertilizer Co.,
Greene, Barnette E., Jr., Vero Beach
Greene, R. E. L., Department of Agr. Econ., U. of
Fla., Gainesville
Grieneisen, L., Jr., Weirsdale


Griffin, B. H., Jr., Box 155, Frostproof
Griffin, J. A., Box 1809, Tampa 1
Griffiths, J. T., Citrus Exp. Sta., Lake Alfred
Groebe, Russell A., Box 1429, Cocoa
Groff, G. Weidman, Laurel
Groff, H. C., Palmetto
Groover, Ben H., Lake City
Grossenbacher, J. G., Plymouth
Grossenbacher, S. A., Box 66, Apopka
Goldroeber S., U. of Miami, Box 1015, S. Miami
Grove, Wm. R., Laurel
Growers Fertilizer Agency, Lake Alfred
Guest, Mrs. Amy, 465 E. 57th St., New York, N. Y.
Gunn, C. D., Rt. No. 1, Micanopy
Hale, Roger H., Rt. No. 1, Palmetto
Hall, C. B., U. of Fla., Horticulture Dept., Gainesville
Halsey, L. H., Fla. Agr. Exp. Sta., Gainesville
Halter, E. T., Box 110, Palm Beach
Hamilton, Joseph, Rt. No. 1, Box 798, Yuma, Arizona
Hamilton, Mrs. Madelaine, 630 Ave., B., N.W.,
Winter Haven
Hamm, Freeman R., City of Lakeland, St. Dept.,
Hammerstein, C. P., Hammerstein Groves, Hollywood
Hanna, L. C., Hanna Rd., Lutz
Harding, Dr. Paul L., U.S.D.A., Orlando
Harkeson, J. E., 624-7th St., N.W., Winter Haven
Harkness, R. W., Sub-Tropical Exp. Sta., Homestead
Harshman, W. W., Highlands Fertilizer Co., Sebring
Hardwick, J. E., Jr., P. O. Box 669, West Palm Beach
Harz, A. W., 13 W. Underwood Ave., Orlando
Hartt & Son, Inc., Box 308, Avon Park
Hatch, Hugh B., Dunedin
Hayman, W. Paul, P. O. Box 711, Bartow
Hayslip, Norman C., Box 1198, Ft. Pierce
Hayter, W. Burns, P. O. Box 536, Leesburg
Hayward, Wyndham, Lakemont Gardens, Winter Park
Hector Supply Co., Box L No. 1311, Miami
Heindrick, E. P., 5830 N.W. 7th Ave., Miami
Henderson, H. Cecil, Box 1448, Winter Haven
Hendrickson, Rudolph, Citrus Exp. Sta., Lake Alfred
Hennes, Jaffa E., S. Lake Apopka Citrus Growers Assn.,
Henry, Arthur M., 1177 Zimmer Dr., N.E.,
Atlanta, Ga.
Henry, W. M., Box 508, Plant City
Herlong, Byron, Leesburg
Hill, Arhur M., Jr., Box 306, Vero Beach
Hills, Walter A., P. O. Box 1055, Lake Worth
Hines, T. R., Box 397, Tampa
Hodnett, J. Victor, Box 958, Winter Haven
Holcomb, E. D., Jr., Winter Haven
Holden, B. Heath, Rt. No. 2, Box 486, Homestead
Holtsberg, Harold, 132 N. 12th St., Ft. Pierce
Holzcker, Richard, Babson Park
Hope, M. E., 513 W. Magnolia Ave., Dade City
Hopkins. E. F., Citrus Exp. Sta., Lake Alfred
Horton, Mrs. Wm. H., Haines City
Howard, Frank L., Box 996, Winter Haven
Huff, Norman V., Box 5, Winter Haven
Huggart, Richard, Box 442, Bartow
Hughes Seed Store, 116 S. Miami Ave., Miami 36
Hughes, W. H., Box 287, Elsa, Texas
Hundertmark, B. W., Clewiston
Hunter, George J., Orlando Livestock Co., Deer Park
Hunter, William P., 1039 W. Cypress St., Gainesville
Huppel, J. B., Windermere

Husmann, Dr. W., 646 Seminole Drive, Winter Park
Hutchinson, J. H., Rt. No. 1, Box 139K, Avon Park
Idlewild Grove, Rt. No. 4, Box 1080, Tampa
Ingram, Dr. Esther M., 204 Professional Bldg.,
Winter Haven
Jacobs, W. A., 317 S.E. Fifth Ave., Delray Beach
Jalarmy Citrus Groves, Minneola
James, Robert H., Box 635, Dunedin
Jamison, F. S., University of Fla., Gainesville
Jimenez, M. A., Minute Maid Corp., Plymouth
Joffre, David C., 29 S. Court St., Orlando
John's Plants, Seeds & Bulbs, c/o John Masek, Apopka
Johnson, J. A., P. O. Box 501, Avon Park
Johnson, R. S., 929 E. 10th St., Sarasota
Johnson, Warren O., Box 1058, Lakeland
Jones, H. L., State Plant Board, Gainesville
Jones, W. J., Di Giorgio Fruit Corp., Winter Haven
Jordahn, A. C., Box 292 Coconut Grove, Miami 33
Jorgensen, M. C., Box 233, Ruskin
Kanawha Groves, 209 Gates Bldg., Charleston, W. Va.
Karst, Art, Box 1110, Orlando
Kasper, P. E., P. O. Box 906, Tampa
Kazaros, Robert S., 1610 Delaney St., Orlando
Keel, Darnell, 2706 Price Ave., Tampa 9
Keene, R. D., Box 338, Winter Garden
Keil, P. F., 530 N. E. St., Raleigh, N. C.
Kelbert, David G. A., Box 678, Manatee, Sta.,
Kelly, Dr. Reba Allen, Fla. Southern College, Lakeland
Kelsheimer, E. G., Box 678, Manatee Sta., Bradenton
Kempf, Mrs. E. J., King Grove, Eustis
Kendall, Harold E., Box 868, Goulds
Kent, L. C., Box 806, Orlando
Kesterson, J. W., Citrus Exp. Sta., Lake Alfred
Kew, Theo. J., 1721 Westchester Ave., Winter Park
Kime, Charles D., Box 232, Ft. Pierce
King, John R., 1201 4th St., N.E., Winter Haven
King, Percy M., Box 42, Quincy
Kingshury, Miss Joan, Box 124, Lake Wales
Kirkley, Al. G., Box 1112, Winter Haven
Knox, Jean H., P. O. Box 898, Haines City
Kransch, Kenneth, 1000 Widensor Bldg.,
Philadelphia 7, Pa.
Krome, Isabelle B., Miami
Krome, William H., Box 596, Homestead
Krome, Mrs. William J., Box 596, Homestead
Kuitert, L. C., Exp. Sta., Gainesville
Ladeburg, C. F., Box 6085, West Palm Beach
Lamb, Geo., Marianna
Lamont, Henry, Rt. No. 2, Ft. Pierce
Larson, L. J., Winter Haven
Lawless, W. W., 1645-16th St. N.W., Winter Haven
Lawrence, Fred P., 402 Newell Hall, Univ. of Fla.,
Lee, W. S., Box 176, Mims
Leibovit, Arthur B., Winter Rose Apts.,
403 N. Olive Ave., West Palm Beach
Leonard, Chester D., 631 "H" N.W., Winter Haven
Lewis, D. E., Box 1171, McAllen, Texas
Lewis, H. F., Terra Ceia
Link, O. D., Davie Rd., Ft. Lauderdale
Lippincott, Mrs. W. A., P. O. Box 997, Stuart
Lipscomb, S. F., Bartow
Little, C. S., Odessa
Little, H. W., 311 Horticulture Bldg.,
Univ. of Florida, Gainesville
Livingston, Bert, 3024 Fair Oaks Ave., Tampa


Lockett, Norwood A., Box 358, Leesburg
Logan, J. H., County Agent, Box 540, Clearwater
Long, Wallace T., Box 1198, Ft. Pierce
Lord, E. L., Sub-Tropical Gardening, Ft. Myers
Lorz, A. P., Fla. Agr. Exp. Sta., Gainesville
Loucks, K. W., Lake Alfred
Lucas, G. H., Peninsular Fertilizer Works,
Box 3272, Tampa
Lundberg, Ernest C., 1319 N.W. Second Ave.,
Lyle, J. I., Rt. No. 5, Box 888, Orlando
Lynch, S. John, Rt. No. 1, Box 185B, Homestead
MacDowell, Louis G., Box 1720, Lakeland
Mackay, Mrs. R. F. B., Lake Alfred
Madsen, H. S., Lake Morten Apts., Lakeland
Magie, Robert 0., 2906 Ninth Ave., W., Bradenton
Malcolm, J. L., Rt. No. 2, Box 508, Homestead
Manfre, Stephen J., 742 Liberty Ave., Cor. Essex St.,
Brooklyn, N. Y.
Marler, Buck, Fla. Fertilizer Co., Lakeland
Marlow, Wm. L., Box 1709, Jacksonville
Martin, Chas. H., 802 E. Hamilton, Tampa
Martsolf, J. D., Ocklawa
Masek, John, Apopka
Masten, Harold R., 151 Grace Terrace, Palm Beach
Mathias, A. F., Box 183, Lake Hamilton
Mathias, F. C., Haines City Citrus Grove Association,
Haines City
Maulhardt, Richard F., Rt. No. 1, Box 579,
Camarillo, California
Maxcy Fertilizers, Inc., E. R. Johnston, Frostproof
Maxwell, Lewis S., Jackson Grain Co., Tampa 1
Maxwell & Anderson, San Mateo
Mayeux, Herman S., Fla. Agr. Supply Co., Jacksonville
Mayfield, Harry, 608 Easton, Lakeland
Mayo, Nat, Ocala
Mayo, The Honorable Nathan, Commissioner of Agr.,
Meckstroth, Dr. G. A., 415 N. Parramore, Orlando
Mell, James R., 409 Candler Bldg., Atlanta, Ga.
Menninger, Edwin A., Stuart
Mercer M. T., Box 181, Coral Gables 34.
Merrill, G. P., State Plant Board, Gainesville
Merrill, W. H., State Plant Board, Gainesville
Meserole, Mrs. George, San Mateo
Michael, Joe E., Box 324, Palmetto
Miller, C. E., 2598 Taylor St., San Francisco, Calif.
Miller, E. W., P. O. Box 1435, Clearwater
Miller, H. N., Dept. of Plant Pathology, Gainesville
Miller, Leon, Rt. No. 6, Orlando
Miller, Ralph L., Plymouth Citrus Growers Association,
Miner, James T., P. O. Box 341, Boynton Beach
Minute Maid Corp., Plymouth
Mooers, Neal D., Babson Park
Moore, Clarence H., Drawer 31, Winter Haven
Mooty, A. F., Box 814, Winter Haven
Morgan, Charles E., 1116 E. Livingston, Orlando
Morrell, P. C., 431 E. Central Ave.,
Eola Plaza, Apt. 402, Orlando
Morrow, William B., 1525 Sunset Place, Ft. Myers
Morse, John, 729 Indian River Dr., Ft. Pierce
Morton, J. F., 113 Mendoza, Coral Gables
Mounts, M. U., County Agent, Box 70, W. Palm Beach
Mowry, Harold, 2455 University Station, Gainesville
Mullen, Harris, Fla. Grower Magazine, Inc., Tampa
Mullinax, H. S., 315 Ave. B, N.E., Winter Haven

Mustard, Margaret J., Box 1015, Univ. of Miami,
Myers, C. J., General Delivery, Tallahassee
Myers, Forrest E., Fla. Agr. Extension Service,
McBride, J. N., Union Sta., Bldg., Savannah, Ga.
McCallum, J. B., Hastings
McClanahan, H. S., State Plant Board, Gainesville
McClure, George G., Lake Alfred
McCoy, Sinclair, 29th Floor, 20 N. Wacker Dr.,
Chicago 6, Ill.
McCubbin, E. N., Potato Laboratory, Hastings
McDonald Division, Clinton Foods, Inc.,
P. O. Box 500, Auburndale
McDuff, O. R., Adams Packing Assn., Inc.,
McIntyre, A. E. C., Box 112, Homestead
McKinnis, Ronald B., Brown Citrus Machinery Corp.,
401 S. Greenleaf Ave., Whittier, California
McPeck, John K., 328 S. Lakeview Dr., Sebring
Nabors, C. M., 1007 Wallace S. Bldg., Tampa
Nanney, W. C., 2419 7th Ave., W., Bradenton
National Fertilizer Assn., 616 Continental Bldg.,
Washington 5, D. C.
Neal, J. H., Hercules Powder Co.,
134 Peach Tree St., N.W., Atlanta, Ga.
Neff, Frank, 605 W. Warren, Tampa
Nelson, Roy O., Univ. of Miami, Box 1015, S. Miami
Nettles, Victor F., Hort. Dept. Agr. Exp. Sta.,
New Smyrna Beach Garden Club, New Smyrna Beach
Newins, Harold S., Director School of Forestry,
Univ. of Fla., Gainesville
Nicholson, Joe, 702 McLendon St., Plant City
Nikitin, A. A., Tennessee Corp. Res. Labs.,
Box 89, College Park, Ga.
Noble, C. V., 1460 N. Brove St., Gainesville
Norman, Gerald G., 2170 Fawoalt Road, Winter Park
Norris, R. E., County Agent, Tavares
O'Byrne, Frank M., Jr., 630 E. 38th St., Hialeah
Ochse, Dr. J. J., Univ. Branch Box 156, Miami
Oglesby, R. M., Box 180, Bartow
O'Kelley, E. B., ACL Railroad Co., Jacksonville
Olsen, H., Davenport
O'Shea, Col. Kevin, 2911 Riverview Blvd., Bradenton
Palmer, Charles, 340 E. Lemon St., Bartow
Palmer, J. M., Box 936, Lutz
Pan American Metal Products Co., Inc.,
401 N.W. 71st St., Miami
Paquin, W. E., Box 519, Winter Garden
Parker, Coleman H., Box 919, Winter Haven
Parris, G. K., Watermelon Laboratory, Leesburg
Patrick, Dr. Roger, P. O. Box 403, Winter Haven
Pedersen, W. C., Lake Wales
Peebles, T. A., Box 877, Vero Beach
Pennsylvania Salt Manufacturing Co.,
1000 Widener Bldg., Philadelphia 7, Pa.
Perkins, Bernard C., Sebring
Pfister, Mrs. H. C., Box 692, Winter Haven
Phelps, George W., Stauffer Chemical Co.
Winter Haven
Pinkerton, David W., City Point
Pipkin, W. A., Safety Harbor
Plaquemines Parish Exp. Sta., Louisiana State Univ.,
Att: Mr. Ralph T. Brown, Superintendent,
Diamond, La.
Platts, Norman G., Rt. No. 2, Box 242, Ft. Pierce



Pollard, W. R., Box 23, Bradenton
Potash Co. of America, 50 Broadway, New York, N. Y.
Pratt, Robert M., Citrus Exp. Sta., Lake Alfred
Price, R. C., 2826 Oak St., Jacksonville
Pride, Richard E., Frostproof
Princess Grove, Box 227, Lake Wales
Pulley, George, P. O. Box 13, Winter Haven
Rainey, B. T., Dolomite Products, Ocala
Ramsey, Vernon E., P. O. Box 7, Suffolk, Va.
Rawls, Glenn, Plymouth
Reark, J. B., Univ. of Miami, Miami
Reasoner, Egbert S., Box 828, Bradenton
Reed, H. M., Fla. Agr. Exp. Sta., Gainesville
Reints, J. E., Winter Haven
Reitz, Dr. J. Wayne, Provost of Agr., Univ. of Fla.,
Reitz, H. J., Citrus Exp. Sta., Lake Alfred
Reuther, Dr. Walter, 415 N. Parramore St., Orlando
Reynolds, B. T., Auburndale
Rich, Frank H., Box 130, Winter Haven
Richbom, J. H., Box 1401, Lakeland
Riegel, Mark, Experiment, Ga.
Riester, D. W., American Can Co., Box 1732, Tampa
Roberts, A. S., Box 694, Ocala
Roberts, Pasco, Box 728, St. Petersburg
Robinson, H. B., Box 2266, Miami 13
Rock, Fairfield, Homestead
Rogers, H. S., Box 823, Winter Haven
Rogers, J. T., P. O. Box 448, Plant City
Rollins, C. F., Clearwater
Root, C. A., Winter Haven
Roper, R. R., Winter Garden
Rosenberger, Stanley, Agr. Ext. Service, Gainesville
Ross, Stuart W., Lake Wales
Rounds, Marvin B., 224 N. Michigan Ave., Glendora,
Rouse, A. H., Citrus Exp. Sta., Lake Alfred
Rowe, W. M., 1007 Wallace S. Bldg., Tampa
Ruehle, Dr. George D., P. O. Box 604, Homestead
Rumpsa, Paul L., Drawer 608, Avon Park
Ruprecht, R. W., Box 327, Sanford
Ruskin Vegetable Coop., Ruskin
Russell, J. C., P. O. Box 177, Sanford
Sahlberg, Nils, Box 252 C-19, Orlando
Sample, J. M., Box 113, Lake Hamilton
Sampson, R. H., Box 7, Mango
Saurman, A. Vernon, Box 686, Clearwater
Savage, Clifford B., 416 El Prado Ave., W. Palm Beach
Savage, Zack, Agr. Exp. Sta., Gainesville
Sawyer, David P., Box 1266, Vero Beach
Schaaf, Harold H., Box 349, David City, Nebraska
Schrader, Otto Lyra, Rua Santa Clara 256,
Rio de Janeiro, Brazil
Schock, W. V., P. O. Box 462, Winter Haven
Schulz, W. H., Winter Haven
Scott, A. G., Box 651, Winter Haven
Sealey, J. H., Box 124, Arcadia
Seims, Mrs. Roy E., Box 663, Avon Park
Sexton, Mrs. Eva., Sexton Groves, Winter Haven
Sexton, W. E., Vero Beach
Seymour, Frank, Box 1327, Lakeland
Sharpe, R. H., Fla. Agr. Exp. Sta., Gainesville
Shinn, Charles M., Lake Alfred
Shoupe, Arthur H., 1130 Fifteenth Ave., N.,
Lake Worth
Showalter, R. K., Agr. Exp. Sta., Gainesville
Siamonton, W. A., Citrus Exp. Sta., Lake Alfred

Silver Lake Estates, Ltd., Leesburg
Simmons, Paul U., P. O. Box 260, Winter Haven
Singleton, Gray, 125 E. Palm Drive, Lakeland
Sites, J. W., Citrus Exp. Sta., Lake Alfred
Sklute, Morris, 1658 21st Ave., N., St. Petersburg
Smiley, Nixon, Homestead
Smith, Al G., Box 88, Palmetto
Smith, F. B., Agr. Exp. Sta., Gainesville
Smith, J. Lee, Box 6, Homestead
Smith, Laurin G., Tennessee Corp.,
619-27 Grant Bldg., Atlanta 1, Ga.
Smith, Paul, 415 N. Parramore St., Orlando
Snell, R. R., Avon Park
Snodgrass, William, Rt. No. 1, Clermont
Soil Science Foundation, Lakeland
Soowal, J. M., 822 Arlington Ave., Orlando
Soule, M. J., Jr., Univ. of Miami, Box 1015, S. Miami
South Florida Motor Co., Sebring
Souviron, Max J., 2845 S.W. 22nd Terrace, Miami 34
Spalding, A., Rt. No. 2, Box 66, DeLand
Speer, H. L., Box 326, Belle Glade
Spencer, Dr. Ernest L., Veg. Crops Lab.,
Box 678, Manatee Sta., Bradenton
Spencer, Herbert, U.S.D.A., Box 112, Ft. Pierce
Spencer, T. C., Haines City
Sprott, Kingswood, Lake Wales
Stabler, D. K., Winter Haven
Stahl, Dr. A. L., Univ. of Miami, South Campus,
Stauffer Cemical Co., Box "K", Apopka
Sterling, H. O., Box 176, Bartow
Stevens, H. E., Amherst Apts., Orlando
Stewart, Tom B., Box 6, DeLand
Stirling, Walter, Rt. No. 1, Ft. Lauderdale
Stoddard, David L., Room 205, Walcaid Bldg.,
Stoner, Dr. Warren H.. Everglades Exp. Sta.,
Belle Glade
Sturrock, David, 1021% Camellia Rd., W. Palm Beach
Sturrock, Thomas T., 1021% Camellia Rd.,
West Palm Beach
Suit, R. F., Citrus Exp. Sta., Lake Alfred
Summerfield Nursery Co., Weirsdale
Sutton, Cliff, 806 Lucerne Terrace, Orlando
Swank, George, Central Fla. Exp. Sta., Sanford
Swann, Thomas, Winter Haven
Swartsel, J. A., Reints Apt., Apt. No. 1,
1st St. & Lake Silver, N.W., Winter Haven
Swartsel, R. V., Lake Gem
Taber, Geo. L., Jr., Glen St. Mary Nurseries Co.,
Glen St. Mary
Tait, W. L., P. O. Box 695, Winter Haven
Talbert, Dale, Vero Beach
Taylor, Mrs. Bright, P. O. Box 623, Ocala
Taylor, J. J., State Chemist, Tallahassee
Thomas, W. W., NACO Fertilizer Co.,
2005 Lake Sue Dr., Orlando
Thompson, Robert, Box 1231, Orlando
Thompson, W. L., Box 1074, Lake Alfred
Thornton, R. P., Box 2880, Tampa
Thullbery, H. A., Lake Wales
Thursby, Isabelle S., Box 68, Orange City
Tiedtke, John, Clewiston
Tilden, Fred, Winter Garden
Timmons, Mrs. Ruth, Belle Glade
Tindal, George, Ft. Pierce Cooperative, Ft. Pierce
Tisdale, W. B., Agr. Exp. Sta., Gainesville



Toffaleti, James P., Box 1231, Orlando
Tomasello, Rudolph P., 911 Bignonia Rd.,
West Palm Beach
Tower, John B., Rt. No. 1, Box 60, Homestead
Townsend, G. R., Box 356, Belle Glade
Tropical Agriculture, S. A., Calle Ermita S/N,
La Habana, Cuba
True, H. H., 438 N.E. 8th Ave., Ft. Lauderdale
Twenhofel, Dr. W. W., P. O. Box 1231, Orlando
United Growers & Shippers Assn., Orlando
United Growers and Shippers Assn.,
14 E. Hamilton St., Tampa
Van Clief, W. C., Winter Haven
Van Horn, M. C., 4517 Beach Tree Circle E.,
Van Kirk, J. C., RFD No. 1, Ft. Lauderdale
Veldhuis, M. K., U. S. Citrus Production Station,
Winter Haven
Volk, Gaylord M., Dept. of Soils, Exp. Sta., Gainesville
Voorhees, R. K., Box 232, Ft. Pierce
Wagner, W. E., Geary Chemical Corp.,
Empire State Bldg., New York, N. Y.
Waldron, Max, Rt. No. 1, Ft. Lauderdale
Walker, Marvin H., 720 Lakeshore Blvd., Lake Wales
Walker, Seth S., 3002 Waverly Ave., Tampa 9
Wallace, Geo. R., Lake Park
Walter, J. M., Vegetable Crops Lab.,
Box 678, Manatee Sta., Bradenton
Wander, Dr. I. W., Citrus Exp. Sta., Lake Alfred
Ward, W. F., Box 177, Avon Park
Ware, C. E., 1411 N. Ft. Harrison, Clearwater
Warren, Alfred, Rt. No. 1, Box 212, Vero Beach
Watson, E. R., Oakadia Groves, Nursery Rd.,
Watson, J. D., 804 S. Dargan, Florence, S. C.
Weetman, L. M., U. S. Sugar Corp., Clewiston
Wenzel, Dr. F. W., Citrus Experiment Station,
Lake Alfred
West, Erdman, 101 Newell Hall, Univ. of Fla.,

West Coast Fertilizer Co., 1601-31st St., Tampa
Westgate, P. J., Central Fla. Exp. Sta., Sanford
White, Alec, 5506 Seminole Ave., Tampa
White, J. F., Julius Hyman Co., Denver, Colorado
Whitmore, Al H., Box 2111, Orlando
Williams, H. A., Kilgore Seed Co., Ocala
Williams, Lyons H., Jr., F. H. Woodruff & Sons, Inc.,
Box 815, Coral Gables
Williams, Miss Myra G., Rockledge
Williams, Ralph E., 1134 N. Yates Ave., Orlando
Wilson, A. E., Citrus Experiment Station, Lake Alfred
Wilson, Don H., Bartow
Wilson, E. H., 91 Norman Bridge Rd.,
Montgomery, Ala.
Wilson, Gaines R., 3853 Little Ave., Coconut Grove
Wilson, H. L., Box 156, Bartow
Wilson, John R., 1036 Francis St., Box 6206,
West Palm Beach
Wilson, J. W., Central Fla. Exp. Sta., Sanford
Wilson, Leo H., Box 48, Bradenton
Wilson, Robert A., Box 25, Hobe Sound
Wilson, Robert G., Rt. No. 2, Box 594, Miami
Winston, J. R., 415 N. Parramore, Orlando
Winter Garden Ornamental Nursery, Inc.,
Box 428, Winter Garden
Wirt, Erle L., Jr., Babson Park
Wolf, Emil A., Everglades Exp. Station, Belle Glade
Wolf, Frederick A., Duke University, Durham, N. C.
Wolfe, Dr. H. S., Head Dept. of Hort., Univ. of Fla.,
Wolfenbarger, D. O., Rt. No. 2, Box 508, Homestead
Woods, V. E., Box 734, Davenport
Yonge, J. R., Box 788, Ft. Pierce
Young, Dr. C. T., Box 948, Plant City
Young, T. W., American Fruit Growers, Ft. Pierce
Ziegler, Louis W., College of Agr., Univ. of Fla.,
Zill, L. H., 813 N. Federal Highway, Delray Beach
Zoffay, John C., Frostproof





Offi cers for 1950 ........................ ....................... ......... IV
Officers for 1951 .......... ................ ..............................-.... V
Constitution and By-Laws ........................................................... VII
Award of Honorary Memberships............. ............ -...........-..-.... IX
List of Members ............ ............ ..... ..................... ......... .... XI
President's Annual Address, Leo H. Wilson, Bradenton...................... ........... .1
Partial Mobilization and the Florida Fruit and Vegetable Industry, Dr. J.
Wayne Reitz, Provost for Agriculture, University of Florida, Gaines-
ville ...................................................... 3

The Effect of 2,4-D on Pre-Harvest Drop of Citrus Fruit Under Florida
Conditions, F. E. Gardner, Philip C. Reece and George E. Horanic,
U. S. Department of Agriculture, Orlando...........-.......... .....
The Chemical Composition of Irrigation Water Used in Citrus Groves,
I. W. Wander and H. J. Reitz, Citrus Experiment Station, Lake Alfred
Ground Water Resources of Florida, Herman Gunter, Florida Geological
Survey, Tallahassee .-....... .. .......................................
Portable Irrigation on the Ridge, Morton Howell, Waverly........................
The Response of Young Valencia Orange Trees to Differential Boron Supply
in Sand Culture, Paul F. Smith and Walter Reuther, U. S. Department
of Agriculture, Orlando .. ....................... ---- ....
Rio Grande Gummosis, Its Occurrence in Florida Citrus, J. F. L. Childs,
U. S. Department of Agriculture, Orlando................................ ..............
Present Status of Spreading Decline, R. F. Suit and H. W. Ford, Citrus
Experiment Station, Lake Alfred..............................................
The Purple Mite and Its Control, W. L. Thompson and J. T. Griffiths, Jr.,
Citrus Experiment Station, Lake Alfred..................................................
Florida's Stake in Plant Quarantine Enforcement, Avery S. Hoyt, Chief,
Bureau of Entomology and Plant Quarantine, Washington, D. C........
Possibilities for the Use of Concentrated Sprays on Citrus in Florida, James
T. Griffiths, C. R. Stearns, Jr., and W. L. Thompson, Citrus Experiment
Station, Lake Alfred................................................... .. ....... .....


The Effect of Variable Potash Fertilization on the Quality and Production
of Duncan Grapefruit, John W. Sites, Citrus Experiment Station, Lake
Alfred ......................... .-----..----------------------- 60
Panel on Parathion, Howard A. Thullbery, Lake Wales.---.... ............-------------. 68

Control of Late Blight and Gray Leaf Spot of Tomatoes with New Fungi-
cides, Robert A. Conover, Florida Agricultural Experiment Stations,
Sub-Tropical Experiment Station, Homestead....----.................---------- 89
Fertilizer-Insecticide Combination for Armyworm, Mole-Cricket and Wire-
worm Control, D. O. Wolfenbarger, Florida Agricultural Experiment
Stations, Sub-Tropical Experiment Station, Homestead, and E. G.
Kelsheimer, Florida Agricultural Experiment Stations, Vegetable Crops
Laboratory, Bradenton ................ --------------------------93
Toxic Insecticide Residues of Vegetables, J. W. Wilson, Florida Agricul-
tural Experiment Stations, Central Florida Experiment Station,
Sanford ...............------------------- ---------- 95
Processing and Labeling Pesticides, M. C. Van Horn, Jacksonville................ 99
The Role of the Regional Vegetable Breeding Laboratory in Breeding and
Testing New Vegetable Varieties, S. H. Yarnell, U. S. Regional Vege-
table Breeding Laboratory, Charleston, South Carolina.......................... 102
New Vegetable Varieties for Florida, David G. A. Kelbert, Florida Agri-
cultural Experiment Stations, Vegetable Crops Laboratory, Bradenton 108
Effect of Low Nitrate Nitrogen on Growth of Potatoes, Gaylord M. Volk and
Nathan Gammon, Jr., Florida Agricultural Experiment Station,
Gainesville ................................----------- 112
Effects of Soluble Soil Salts on Vegetable Production at Sanford, Philip J.
Westgate, Florida Agricultural Experiment Stations, Central Florida
Experiment Station, Sanford .......... ......-------------....... 116
A Nematode Attacking Strawberry Roots, A. N. Brooks, Strawberry Labora-
tory, Plant City, and J. R. Christie, U. S. Department of Agriculture,
Sanford .-----...- --------------------------------- 123
Nitrogen Transformation in Seedbeds as Affected by Nematocidal Treat-
ment, Ernest L. Spencer and Amegda Jack, Florida Agricultural Ex-
periment Stations, Vegetable Crops Laboratory, Bradenton------.................... 125
Graywall of Tomatoes, Warren N. Stoner, Florida Agricultural Experiment
Stations, Everglades Experiment Station, Belle Glade..................----......---....... 129
Quality of Florida Potatoes and Some of the Factors Affecting Quality,
R. E. L. Greene, Florida Agricultural Experiment Station, Gainesville 136
Mulching Vegetable Crops with Aluminum Foil, Donald S. Burgis, Florida
Agricultural Experiment Stations, Vegetable Crops Laboratory,
Bradenton .-................ --------.............. -- 141
Transitory Effects of 2,4-D on the Watermelon Plant When Absorbed
Through the Roots, Clyde C. Helms, Jr. and G. K. Parris, Florida Agri-
cultural Experiment Stations, Watermelon and Grape Investigations
Laboratory, Leesburg ................. ------------- ----------144


Comparison of Plating Media Used for the Estimation of Microorganisms
in Citrus Juices, E. C. Hill and L. W. Faville, Citrus Experiment
Station, Lake Alfred .............................................. ................. ....... 146
Relative Efficiencies of Several Liquid Presumptive Media Used in the
Microbiological Examination of Citrus Juices, L. W. Faville and E. C.
Hill, Citrus Experiment Station, Lake Alfred..................................... ..... 150
Storage Changes in Citrus Molasses, R. Hendrickson and J. W. Kesterson,
Citrus Experiment Station, Lake Alfred..................... .............. ..... 154
An Index of Pasteurization of Citrus Juices by a Rapid Method of Testing for
Residual Enzyme Activity, Theo. J. Kew and M. K. Veldhuis, U. S. Citrus
Products Station, Winter Haven..... .................................. 162
Storage Changes in Frozen Concentrated Citrus Juices-Preliminary Re-
port, Edwin L. Moore, Richard L. Huggart, and Elmer C. Hill, Citrus
Experiment Station, Lake Alfred-.....--..................-............... 165
A Method for Estimating Soluble Solids in Dried Citrus Pulp, Owen W.
Bissett, U. S. Citrus Products Station, Winter Haven............................. 174

The Genus Allamanda in Florida, Egbert S. Reasoner, Bradenton............. 179
Some Ornamental Trees and Shrubs Native to South Florida, Geo. D.
Ruehle, Florida Agricultural Experiment Stations, Sub-Tropical Ex-
periment Station, Homestead ............. ............................. 180
The American Hibiscus Society, Norman A. Reasoner, Bradenton................. 183
Interesting Uses of Woody Plants, George L. Taber, Glen St. Mary-.......... 187
Soil Sterilization, H. N. Miller, Florida Agricultural Experiment Station,
Gainesville ----......----- ...... ........................ .. 190
Greenhouse Foliage Plants in Florida, Peter Pearson, Plymouth..........-........ 192
The Daylily in Florida, Wyndham Hayward, Winter Park................................ 194
Horticultural Research with Camellias, G. H. Blackmon, Florida Agri-
cultural Experiment Station, Gainesville..........................---.... ..... 198
Notes on Camellia Diseases, Erdman West, Florida Agricultural Experi-
ment Station, Gainesville ................. .. ............................. 200
Factors Affecting the Keeping Quality of Cut Flowers, R. D. Dickey, Flor-
ida Agricultural Experiment Station, Gainesville.............................. 203
Insect Control on Ornamental Plants of the Home Garden, L. C. Kuitert,
Florida Agricultural Experiment Station, Gainesville.............. ............ 206

Fairchild Tropical Garden, Charles H. Crandon, Coconut Grove...........-. 209
Radio Garden Clubs, Pasco Roberts, St. Petersburg................................. 213
We Make A Men's Garden Club Tick, Bert Livingston, Tampa................. 215



Fruit Gift Packages, Edward A. Ash, Homestead................ .............- ...-- 217
Observations of Some of the Newer Mangos During the Year of 1950, L. H.
Zill, Delray Beach ........... ...................... .................. 219
Monthly Meetings on Tropical and Sub-Tropical Fruits, M. U. Mounts,
West Palm Beach ................. ......................... 220
Marketing Fresh Lychees, DeWitt Eaton, Sarasota................................ 222
A Survey of Diseases Lethal to Tahiti (Persian) Limes in Dade County,
C. M. Gates and M. J. Soule, Jr., University of Miami, Coral Gables.... 225
Packaging and Storage of Persian Limes, Margaret J. Mustard, University
of Miami, Coral Gables............. ... .................... 228
Studies of Stylar End Rot of Tahiti Limes, Robert A. Conover, Florida
Agricultural Experiment Stations, Sub-Tropical Experiment Station,
Homestead ........................................ 236
Twenty Years After, H. S. Wolfe, College of Agriculture, University of
Florida, Gainesville ....................... .................. 240
Tropical and Sub-Tropical Fruits in Pinellas County, C. E. Ware, Clear-
water ................ -----------.......... ........ 245
The Future of Tropical and Sub-Tropical Fruits in Florida, E. V. Faircloth,
West Palm Beach ....-.............. .................... 247
The Propagation of Sub-Tropical Plants by Cuttings, A Progress Report,
J. J. Ochse and J. B. Reark, University of Miami, Coral Gables--- ........ 248
Weed Control Studies Around Young Avocado Trees, Roy W. Harkness,
Florida Agricultural Experiment Stations, Sub-Tropical Experiment
Station, Hom estead ........... .. ..................................... 251
The Introduction into the United States and the Culture of Eleocharis
Dulcis, The 'Matai' of China, G. Weidman Groff, Lingnan Plant Ex-
change, Laurel .. .................... ................... 262
Additional Notes on Mango Budding, S. John Lynch and Roy Nelson, Uni-
versity of Miami, Coral Gables...... .... ......... ......... .................. 266

Report of Executive Committee............................... ............... 269
Report of Treasurer................. ..... .. .................... 270
General Business Meeting of Society, Winter Haven, Oct. 31, and Nov.
2, 1950 ............................... ................................................. .................... 271
Resolutions .................... ............. .........271
Necrology Committee ..................................................... 272 272




It is with keen pleasure I welcome the
members and friends of this, the sixty
third session of the Florida State Horti-
cultural Society. We have experienced
many startling events since our meeting
one year ago in Tampa. Increased re-
turns have been received for horticultural
and agricultural products. We have been
saddened by the loss of friends and the
ravages of war. We look to the future
with hopes for peace and security.
The 1949 proceedings of the sixty sec-
ond session of the Florida State Horticul-
tural Society, relates the passing of the
late Frank Stirling of Davie, Florida,
immediate past President of the Society.
Every member I am sure joins me in pay-
ing tribute to one of Florida's leading
Horticulturists. Frank was a loyal mem-
ber, and his going has been a great loss
to the horticultural interests of Florida.
The Korean war, now coming to a
close, has taken the lives of thousands of
our American men. May we pay homage
to the gallant fighting of our soldiers who
paid the supreme sacrifice, and those
wounded and missing in action. The
United States, together with other U.N.
forces have about won this war. My
humble prayer is we will win a lasting
The so-called "Florida Hurricanes"
have been a dime a dozen this season.
We have experienced ten hurricanes with
two hits on Florida. The Gulf of Mexico
blow that struck Cedar Key, did a tre-
mendous damage to this West Coast
town. The second hurricane struck in
the Miami, Hollywood, Okeechobee, In-
dian River Section. An estimate of
$15,000,000 dollar damage has been re-
ported. Florida's East Coast Agricul-
tural interest suffered heavy losses. The
damage to the citrus crop from the lower

East Coast, extending North through
Eastern Polk County, Orange and Lake
Counties, estimate around 3,000,000
boxes of fruit, with grapefruit running
2,500,000 boxes and all other citrus fruits
500,000 boxes. These figures are subject
to change as more damage shows up,
especially the heavy drop that occurs
from bruises and thorn injury.
Florida's agricultural interest is con-
tinually being subjected to the introduc-
tion and attack by foreign insect pest
and diseases. The dreaded South Ameri-
can disease known as Tristeza that has
killed thousands of citrus trees in that
country, may be present in the State of
Louisiana. Two hundred trees in a
planting on the Mississippi River Delta
near New Orleans, have died recently
from Tristeza, or some other form of
tree decline. If not Tristeza, it could be
Quick Decline. This form is taking a
heavy toll of citrus in California. Quick
Decline might be termed a twin brother
to Tristeza. The Florida Experiment
Station, the United States Department of
Agriculture and the Florida State Plant
Board have visited this area. They are
making a careful study on the type of
decline in the New Orleans area. What
can we do to safeguard Florida's citrus
It has often been pointed out that the
State of Florida is in a vulnerable posi-
tion for the introduction of insects and
diseases that could result in the destruc-
tion of many of Florida's important agri-
cultural crops. I can't urge the members
of this group too strongly the necessity
of cooperating with the State Plant
Board and the Bureau of Entomology
and Plant Quarantine, in their rigid en-
forcement to the letter of all existing
laws and regulations. I am indeed glad
to report how fortunate we are to have
as a speaker at the General Session on
Thursday morning, the Chief of the


Bureau of Entomology and Plant Quaran-
tine from the United States Department
of Agriculture, the Honorable Avery S.
Hoyt. Mr. Hoyt has proved a valuable
friend to Florida. I am sure the Horti-
cultural Society membership joins me in
expressing our sincere appreciation for
his presence in the State and appearing
on the program.
The five sections that comprise the
membership of the Florida Horticultural
Society, namely: the Citrus section, the
Vegetable section, the Processing section,
the Ornamental section, and Krome
Memorial section, have as a whole ex-
perienced a very fine year. The interest
of these groups have been well cared for
in many lines of research. The Florida
Experiment Station, which includes the
Sub Experiment Stations, and the United
States Department of Agriculture are
conducting much needed research work.
Florida appreciates this work and grow-
ers realize how much they have bene-
fited in the past from completed experi-
ments. May I throw out a challenge to
the Society to lend every effort to keep
this research and experiments now being
conducted, driving ahead at full speed.
We can keep these Institutions of service
operating if we see the needed appropri-
ations are provided.
Florida Citrus Mutual swung into op-
eration last season. This grower organi-
zation is to be congratulated for tying
ninety percent of all citrus produced in
the State, under one control. This may
be considered the mammoth Co-op of
growers for all times. The fact that so
many Florida Citrus Growers, Shippers
and Processors have come together on
common grounds, to pool their interest
for the betterment of the industry, has
benefited the Florida Citrus Industry
many millions of dollars. Its successful
operation has gained recognition from
other fruit producing areas of the world.
The planting of citrus in Florida con-
tinues at a very rapid rate. Good prices

for fresh fruit, canned and frozen con-
centrate has given impetus to the whole-
sale planting of thousands of acres in the
last eight to ten years. At this point,
may I throw out a word of warning to
growers who contemplate new plantings.
There will come a time when you may
wish you had continued to pasture that
marginal land you are now preparing to
plant. With a high acre return on the
investment, coupled with open winters,
growers seem to forget the early precau-
tions given on the importance of "grove
site selection." Are we ignoring the
value of a good fertile soil, a soil well
supplied with humus that maintains
moisture? A well drained soil, and one
adaptable to root stock and variety.
Good elevation and air drainage is essen-
tial. In 1895, "Old Man Winter" struck
hard, and drove the Citrus Industry
South. If we exercise good judgment,
and are cautious in selecting sites for
grove plantings, we will by the law of
averages, develop a profitable orchard.
I believe the Florida State Horticul-
tural Society is the leading one of its
kind in the world. We members should
feel proud to be associated with such a
wonderful organization. The program
for this session consists of seventy three
subjects, with as many or more speakers.
A very fine program has been arranged,
and I appreciate the efforts made by the
Vice Presidents of each Section in de-
veloping the programs we are to receive.
When I say we have the finest Horti-
cultural Society in the world, there is a
reason to back this statement. The exist-
ence of this Society just doesn't happen
so. Hard work over these many years
by its Officers have borne fruit. This
particular year, it has been my privilege
as your President, to observe the Officers
in action. Nineteen members of the
Executive Committee, (which includes all
Officers) have held eight meetings during
the year in Winter Haven. Please bear
in mind not a single person receives a


penny for services rendered, and no ex-
penses allowed for travel. It required
long trips from Miami in the South,
Gainesville in the North, and from the
East and West Coasts in attending these
meetings. I have been greatly impressed
with the fine spirit, loyalty to duty, and
the untiring efforts of the officers and
Executive Committee. Every member
has performed his duties well. I have a
very warm place in my heart for their
splendid services.
We have four officers that do the
greater part of the work in an organiza-
tion of this kind. I especially wish to
commend them for their fine accomplish-
ments this year. The Secretary, Dr.
Ernest L. Spencer-Bradenton; the
Treasurer, Mr. Lem P. Woods-Tampa;
the Assistant Secretary, Mr. Ralph P.
Thompson-Winter Haven; and the
Editing Secretary, Mr. W. Lacy Tait-
Winter Haven. We owe these men a
great deal of credit. I wish I had the
space to enumerate every detail these
Officers executed in bringing the Society

up to its high standard. I am sure their
reports will in part tell the story.
I would like very much to see the mem-
bership of the Florida Horticultural
Society increased. We should have sev-
eral thousand members. Florida is
blessed by having a large number of
intellectual growers. They would benefit
the Society, and I am sure the Society
would be of much value to them. We
naturally trust everyone in attendance
who are not members, will become mem-
bers during this session. Dues from the
members pay for the proceedings. If dues
come in early, the proceedings can be
published on time. Every member can
have a part in the successful operation of
the Society.
On behalf of the membership, may I
express sincere appreciation to the city
of Winter Haven for being host to the
Florida State Horticultural Society. Our
stay in your fair city will be a pleasant
one. A very interesting and profitable
meeting is assured.


University of Florida
College of Agriculture
The Korean conflict has had and will
have far-reaching effects on our national
economy. It has resulted in much specu-
lation in recent months on what effects
our increasing tempo of military prepa-
ration will have on our whole economy,
including agriculture. Tonight I have
chosen to join the speculators in order
tat we may consider some of the impli-
ations of the defense program on the
economic position of Florida farmers,
nd on fruit and vegetable producers in

Any attempt to assess the possible
effect of an enlargement of our defense
effort, and the resultant expansion of our
national budget on the economic position
of the Florida fruit and vegetable indus-
try, requires assumptions on the probable
magnitude of the defense program and
of prospects for peace. Let us consider
two major assumptions. One assumption
is that we are facing a period of at least
a few years in which defense activity
will continue at a much higher level than
in previous post-war years. Present
plans call for a military force of 3 mil-
lion men, or approximately twice as many
as are now under arms. To maintain
this force and provide the accompanying
armaments, expenditures for defense will


probably reach an annual rate of at least
30 billion dollars for the fiscal year be-
ginning next July 1. This compares with
estimated expenditures of about 20 bil-
lion dollars during the current fiscal year
and approximately double the amount of
the previous two years. A further as-
sumption is that there will be no armed
conflict between major world powers. An
open war between the United States and
a country with the military might and
productive capacity of Russia would
change our defense policy from one of
protection to one of survival, and, under
such circumstances military expendi-
tures, manpower and material require-
ments would be strained to the limit-
more than ever before in our history.
Assuming, however, that our defense
requirements in terms of expenditures
and manpower needs will be approxi-
mately as I have outlined, let us first
think of meeting these requirements and
their effects on our economy in general
before assessing the probable effects on
Florida fruit and vegetable producers.
As we have already witnessed, the im-
mediate effects of additional outlays for
defense purposes, assuming no other
governmental action, is inflationary. The
Korean conflict caught us operating at
or near our peacetime productive capac-
ity. We had full employment for all
practical purposes, and consumer incomes
and, therefore, consumer demand soon
reached an all-time high. These condi-
tions are quite different from those pre-
vailing in 1941 when another defense
program was started. Then we had many
idle resources. Under current circum-
stances, with no slack to be taken up, an
expansion of our defense program has a
doubly inflationary effect. First, in-
creased defense expenditures mean a
larger volume of money in the hands of
consumers and, therefore, an increased
demand for consumer goods. Second, the
material requirements for an expanded
defense program must be met partially

at the expense of consumer goods, espe-
cially products of a durable nature, such
as refrigerators, stoves, automobiles,
radios, television sets, and housing. The
full effect of each of these situations is
yet to be felt. We are thus placed in a
position where the buying power of con-
sumers is increasing while the products
available for purchase is declining. Under
such circumstances, prices will move up-
ward until a new equilibrium is reached
between available supplies and existing
purchasing power, unless the government
exercises some anti-inflationary meas-
Apprehension over the effect of insert-
ing a larger defense program into our
already strained economy is not limited
to economists and legislators, but is of
vital concern to all. The dollar is in
greater peril than during World War II
or the immediate post-war years. Heroic
measures will be needed to preserve its
purchasing power. This accounts for the
agitation for all out economic controls,
and the broad control powers granted the
President by Congress in the Defense
Production Act of 1950.
There is a tendency, however, to over-
estimate the effect of an expanded de-
fense program on the total supply of all
goods, especially in view of the present
level of business activity and the seem-
ingly imminent shortages in many lines
of consumer goods. The current rate of
business activity and heavy consumer
buying is based in part on fear that pro-
duction of many lines of civilian goods
will be interrupted when the defense
program gets fully under way some
months hence. To be sure, adjustments
in production will be made involving a
reduction in durable consumer goods, but
bans on production seem rather remote.
Recent estimates presented to Congress
by the Defense Department indicate that
the presently projected program of par-
tial mobilization will require about 4
percent of our annual steel production,


and about 7 percent of our productive
capacity of copper, and about 14 percent
of our aluminum at current production
rates. Such demands do not suggest a
sharp diversion of our productive capac-
ity into military channels or that
civilians will face a serious problem of
adjustment to lower consumption levels.
However, when the full level of military
expenditures is reached, the impact on
prices will continue to be inflationary
even though increased production of
military goods will represent but a small
part of the total national production-
now at an annual rate of some 270 billion
Under prevailing economic conditions,
and the impact of an expanded defense
program, fruit and vegetable producers
can look forward to a continued high
level of demand for their products during
the next few years. The demand for
many fruits and vegetables will be bol-
stered by increased Government pur-
chases to meet the food requirements of
a larger armed force. During the last
war we found that the consumption levels
of luxury type foods such as meats, dairy
products, and many fruits and vegetables
were considerably higher among service
personnel than among civilians. As a
result, we can expect the consumption
rate of many of our products to increase
with the expansion of our armed forces.
The effects of increased military pur-
chases should be more noticeable in the
canned and frozen food field, since a high
proportion of such purchases will be in
this form.
Much more important than the in-
creased consumption of our armed
forces is the indirect effect of anti-
inflationary controls on demand for fruits
and vegetables and the great bulk of
other farm products. We have noted
already that increased production for
defense purposes places more purchasing
power in the hands of consumers. For
the economy in general, the inflationary

effects thereof can be counteracted by
credit restrictions, calling for higher
down payments and shorter payment
periods. Yet credit controls tend to in-
crease the demand for farm products.
Such controls make it impossible for
large numbers of consumers to obligate
their future earnings through install-
ment buying. Thus, they are simply
taken out of the market as buyers of dur-
able goods and housing. The result is
that the housewife has more dollars avail-
able for buying food, particularly the
so-called luxury items, such as meats,
green and leafy vegetables, and fruit
juices. However, it should be borne in
mind that the full effects of such controls
will not be noticeable for some months.
Now let us turn to production problems
arising from partial mobilization. There
seems to be little reason to expect any
pronounced production difficulties under
the assumptions made. I have already
indicated that the requirements of our
basic metals for defense purposes will not
be excessive. It does not appear at this
time that there will be any serious short-
ages of farm machinery. Should short-
ages develop, the Government, no doubt,
would hasten to assure adequate produc-
tion through allocating critical materials
to specific industries. Fortunately, the
quality and condition of machinery and
equipment on Florida farms are excellent.
Critical shortages of insecticide mate-
rials are not likely, although some sub-
stitution may have to be made for some
chemicals which require large amounts
of chlorine. Fertilizer supplies should
be adequate to meet normal usage and
production requirements. To be sure,
nitrogen will be required to produce
ammunition for training purposes and
for stock-piling, but demands for such
purposes should represent a comparative-
ly small proportion of our total output
and should not be great enough to affect
the supplies available for agricultural
production, Furthermore, much of the


great capacity for nitrogen production
developed during the war years is not in
use at the present time.
Some manpower shortages will develop
as a result of an increase of one and a
half million men in the armed forces
along with demands for labor in produc-
ing armaments. But such shortages
should be felt least of all in the field of
agriculture. While the effects of the
draft or enlistments on available labor
supplies will be equally distributed
throughout the economy, the increased
demand for civilian labor will be con-
fined largely to the industrial areas of
the North. We should also bear in mind
that a part of our defense production
will be at the expense of goods for
civilian consumption, and that the in-
crease in our labor requirements will be
somewhat less than proportionate to the
expansion of the defense program. Under
such circumstances, and based on our
previous assumptions, Florida fruit and
vegetable producers should not face seri-
ous labor shortages. I might add, how-
ever, that as a precaution against a real
emergency, steps should be taken to pro-
vide for labor-saving techniques and
I mentioned the broad control powers
granted the President in the Defense
production Act passed in the recent ses-
sion of Congress. Failure to exercise
these powers to the fullest has been the
subject of much criticism. Discussion
of controversial subjects often develops
more heat than light, and this is no
exception. The chief clamor has been
for wage and price ceilings, and, if neces-
sary, consumer rationing. Price controls
may make practical politics, but are al-
most certain to have an undesirable
effect on our productive effort and on the
defense program. In times of stress we
are inclined to forget the real function
of price in our capitalistic economy. We
fail to remember that price is the one
and only guide of the producer, that

price is the means by which available
supplies of goods are apportioned among
consumers, so that the amount .which
people wish to buy is just equal to that
which people wish to sell.
As yet, we have failed to find or devise
a means of achieving the delicate balance
that is inherent in the price mechanism
on a free market. In attempting such
operations, some prices are fixed too low
so that production is discouraged and
consumption is increased; the result: a
virtual disappearance of the affected com-
modity from the market. On the other
hand, some prices are fixed too high, so
that consumption is discouraged while
production is increased; and the result in
this case: the accumulation of surplus
supplies. Our experience with price
controls during the last war, particularly
on perishable agricultural products, indi-
cate that we cannot duplicate or replace
the pricing mechanism, and that we
cannot achieve a balance between produc-
tion and consumption without a free
market price.
This is not to say, however, that we
should do nothing about the general level
of prices. No responsible person can be
complacent about the dangers of infla-
tion. We have means by which the
general level of prices can be controlled
without taking on the almost hopeless
task of replacing the pricing mechanism
with a price control program.
If we earnestly desire to check in-
flationary tendencies we can do so by
the Federal Government adopting proper
fiscal policies. This can be done by the
simple expedient of controlling the quan-
tity of money people have to spend
through the use of credit restrictions or
increased income taxes, preferably both.
Direct credit restrictions, such as those
currently in effect on durable goods and
housing, reduce the level of effective
demand for such products. If made in-
creasingly stringent, consumer buying
power will be reduced to the point of


bringing about price declines. Other
effective curbs on credit can be accom-
plished through regulations imposed on
the banking system, through the facili-
ties of the Federal Reserve System.
The possibilities of increasing taxes
to check inflationary pressure has been
recognized by the present administration
and the realities thereof will be apparent
when the monthly pay check comes in
tomorrow. Increased income taxes not
only reduce consumer buying power, but
avoid the inflationary effects of deficit
financing through the media of Treasury
bonds. Yet, as an anti-inflationary
measure, taxation has the fundamental
disadvantage of being extremely unpopu-
lar. As a result, it is difficult politically
to increase the taxation rate to the extent
necessary to affect consumer demand and
in turn the general level of prices. It is
doubtful, therefore, if we shall have the
fortitude to put partial mobilization on a

pay-as-you-go basis, and consequently
the net effect will be inflationary.
To summarize, the over-all effect of
partial mobilization on the Florida fruit
and vegetable industry will be to provide
a stronger demand for products than
would otherwise exist. Production costs
will increase, but no serious shortages
are expected in materials and labor.
There is nothing in the current or future
situation to warrant price controls or
consumer rationing. If they appear to
be needed, the best method of handling
is by controlling the general price level
through tightening over-all credit con-
trols and increased taxation rather than
by interfering with the pricing mechan-
How far we shall go in credit controls
or taxation I do not know, but of this I
am sure; if we do the job which is now
before us-as it should be done-our
sacrifices are going to have to match our
hopes and aspirations for peace.



Bureau of Plant Industry, Soils, and
Agricultural Engineering, United
States Department of Agriculture
Pre-harvest drop of citrus fruit dur-
ing some seasons reaches a high per-
centage of the total crop in certain
varieties. Midseason varieties, such as
Pineapple and seedling sweet oranges,
are generally considered the most prone

to heavy pre-harvest dropping. Periods
of warm, dry weather during the fall
and winter months favor fruit shedding.
Losses from this cause may constitute
as much as one-third of the total crop
and are rarely less than 15 percent. The
Valencia variety is not considered such
a bad dropper, and indeed fruits rarely
fall in such large numbers within a
short time as is frequently observed
with Pineapple orange near the end of
its maturity season. However, the drop
extends over a much longer period in


the case of Valencias, so that the total
losses in this variety also may be very
heavy. The rapid decay of grounded
fruit and also the covering-up of such
fruit from time to time by grove disking
serves to hide from the grower the
magnitude of the losses during a pro-
longed dropping period.
Following the successful use of naph-
thaleneacetic acid and naphthalene-
acetamide to control pre-harvest drop
of apples (3), it was reported by Gard-
ner in 1941 (1) that these compounds
also could be used to materially lessen
the drop of Pineapple oranges in Florida.
However, the relatively high concentra-
tions required and the fact that the
materials were not found to be effective
applied later than November, made the
discovery of doubtful practical value.
More recently the findings of Stewart
and his associates in California have
shown that 2,4-D is much more potent
in controlling the drop of citrus fruits
and, as a result, its use is gaining wide
acceptance in that State. Stewart and
Klotz (4) sprayed Valencia orange trees
in May with a 2,4-D derivative (die-
thanolammonium 2,4-dichlorophenoxy-
acetate) in concentrations of from 5 to
40 p.p.m. and reported a decrease in
fruit drop, compared with the controls,
of up to 55 percent at 40 p.p.m. On
Marsh grapefruit Stewart and Parker
(5) used the same compound in June in
concentrations of 5, 25, 75, and 225
p.p.m and obtained nearly as good con-

trol with the two lower concentrations
as with the higher ones; both of the
latter caused rather severe foliage dam-
age. It should be noted that the sprays
applied in May and June are just prior
to harvest period of these varieties in
California. The trees at this time
would be in a very active condition.
This situation will be referred to later,
as it may have a bearing on the diver-
gent results secured in the studies here
reported with sprays applied in the fall
and winter months.

1948 Experiments
Sprays of 2,4-D and several other
hormone compounds were applied to
Pineapple and Valencia oranges. Trees
were chosen for their comparable size
and crop in blocks of six. Blocks were
replicated ten times and within each
block the following six treatments were
applied to single-tree plots: (1) 2-methyl
4-bromophenoxyacetic acid; (2) 2-
methyl phenoxy alpha-butyric acid; (3)
2-methyl 4-chlorophenoxyacetic acid;
(4) sodium salt of 2,4-D, all four mate-
rials being applied as sprays at concen-
trations of 20 p.p.m. of 2,4-D acid
equivalent; (5) isopropyl ester of 2,4-D
incorporated with dusting sulphur and
used as a dust, also at the rate of 20
p.p.m. of 2,4-D; (6) control plots receiv-
ing no spray or dust.
Sprays were applied on October 15 by
a ground crew with conventional high-
pressure rig. Thorough coverage was

t_ ~ ---------

Treatments Applied October 15, 1948
Cone. 20 p.p.m. Free Acid Equiv.
2-meth. 4-chloro phenoxyacetic
2-meth. phenoxy alpha-butryic
2-meth. 4-bromophenoxyacetic
2,4-D isopropyll ester) in sulphur
2,4-D (sodium salt)

Pre-harvest Drop in Percent of Total Crop
Applied Valencia
As Pineapple (+Splits) (-Splits)
Spray 24.3 37.4 30.9
Spray 26.2 43.5 31.1
Spray 25.1 36.2 28.3
Dust 21.3' 28.7 21.4
Spray 16.3' 36.4 28.8
---. 28.6 32.3 24.3

'Statistically significant. Difference between means of 6.9 required for significance at 1% level.


obtained with 15 gals. of spray per tree.
Temperatures during the time of appli-
cation ranged from 740 to 820 F. The
dust treatments were applied on Octo-
ber 19, a still day on which the tempera-
ture varied from 740 to 770 F. All
previous drops were removed from be-
neath the trees and subsequently all
drops were gathered and counted, begin-
ning November 1 and at weekly inter-
vals thereafter until the crops were
harvested, the Pineapple oranges on
February 14 and the Valencias on
May 4.
The first three compounds listed in
table 1 had previously been found to be
very effective (in a class with 2,4-D) in
delaying abscission of Coleus petioles-
a test used by Gardner and Cooper (2)
to screen a large number of compounds
for effect on abscission. It is. evident
that none of the three had any influence
in controlling the drop of either of
these orange varieties. The data in
table 1, however, serve to show the very
heavy fruit drop frequently encoun-
tered in Florida citrus, and that 2,4-D
applications effected an appreciable
control of this drop in Pineapple
oranges but not in Valencias. The re-
duction in drop of the Pineapple
oranges with the 2,4-D spray amounted
to 43.1 percent of the drop from the con-
trol trees. The dust application was
less effective, due probably to the poor-

er coverage than can be obtained with
Fruit splitting in the Valencias was
quite severe during the fall and winter
of 1948 in this test grove and therefore
all Valencia drops were separated as to
split and sound fruit and counted
separately. The subtraction of splits
from the total drops as presented in the
Valencia section in table 1 did not alter
the conclusion that 2,4-D had no effect
on drop in this variety. Neither was
there any influence of this compound
on the amount of splitting.

1949 Experiments
Because of the frequent use of wet-
table sulphur sprays in Florida for rust-
mite control, it was important to learn
if 2,4-D could be added to such sprays
instead of making a separate applica-
tion. The 1949 experiments were de-
signed to test this point, as well as to
investigate the possibility of higher
concentrations of 2,4-D. Both Pine-
apple and Valencia varieties were in-
cluded in these tests, which included 6
treatments with 10 replications. The
2,4-D (sodium salt) was used at 25 and
50 p.p.m., both with and without wet-
table sulphur (10 lbs. per 100 gal.)
Dual control treatments were set up
consisting of (a) no spray and (b)
sulphur only.
Table 2 discloses a very appreciable

Drop in Percent of Total Crop
Pineapple Valencia
Treatments-Sprays Applied December 19, 1949 Picked Feb. 13 Picked May 5
Control-(no spray) 16.8 14.7
Control-wettable sulphur only 18.7 15.4
2,4-D at 25 p.p.m. 6.8' 17.9
2,4-D at 25 p.p.m. with sulphur 6.1' 17.4
2,4-D at 50 p.p.m. 4.0' 19.8
2,4-D at 50 p.p.m. with sulphur 5.3' 14.0
'Statistically significant. Difference between means of 5.88 needed for significance at the 1%o level.


and highly significant reduction of fruit
drop in the case of Pineapple oranges
at both concentrations of 2,4-D. The
higher concentration (50 p.p.m.), while
appearing to be the more effective, is
not significantly so, and the use of this
high concentration would not seem
justified. In this experiment the use
of 25 p.p.m. resulted in a saving of 1.7
boxes of fruit per tree, compared with
the average drop of the controls.'
It is evident from table 2 that 2,4-D
can be combined with wettable sulphur
without loss of effectiveness. Appar-
ently there is considerable leeway in
the timing of the 2,4-D application
(October, November, or December)
and combining it with wettable sulphur
will rarely present interference with
the timing needed for rust mite control.
The 1949 trials with 2,4-D, like those
in 1948, were without effect on Valen-
cias. These results are in marked con-
tradiction to those reported from Cali-
fornia with this variety. Until more
work is done with Florida Valencias,
the reason for this disagreement in re-
sults can only be surmised. Trees
sprayed in May or June in California
are in a much more active condition
than the trees in Florida that were
sprayed in the fall and winter. It is
possible that the difference in time of
spray application is responsible and
that earlier application would be effec-
tive in Florida. If this is the correct
explanation, it is strange that the Flor-
ida Pineapple trees respond so marked-
ly to 2,4-D at any time during their dor-
mant period.
Effect On Other Varieties
Sweet seedling oranges, Temples, and
Marsh grapefruit were also sprayed in

'A concentration of 25 p.p.m. of 2,4-D was made by
adding 2.1 oz. of the commercial sodium salt (83
percent 2,4-D equivalent) to 500 gal. of spray. Be-
cause it is readily soluble in water, it was added
directly to the spray tank and agitated briefly before

1949. The treatments consisted of con-
trols and 2,4-D sprays at 25 and 50
p.p.m. without wettable sulphur. Each
treatment was applied to single-tree
plots with 10 replications. Unfortun-
ately, picking crews harvested the crops
without notifying the experimenters
and thus no record of the amount of
crop on the trees at picking date was
obtained on which to base percentages
of drop. With only the week-by-week
pick-up record of dropped fruit from
the sprayed and non-sprayed trees, no
definite statement can be made as to the
effectiveness of the sprays on these
three varieties. The partial data, how-
ever, suggest that 2,4-D was reasonably
effective on sweet seedlings and Temple
oranges but was not at all effective on
Marsh grapefruit.

Injury To Citrus From 2,4-D
Fall and winter applications of 2,4-D
at a time when young growth is not
present and not anticipated for some
weeks to come, have not resulted in any
observable effect on the foliage on the
tree at the time. In the following spring
when new foliage appears there are
nearly always a few leaves to be found
that show 2,4-D effects. This is true
almost regardless of the weakness of
the concentration used. The deformed
leaves are few in number and may not
appear except on occasional trees, and
they are not cause for alarm.
The lack of damage from low concen-
trations of 2,4-D should not lull the
grower into the belief that high concen-
trations can be safely applied to or
around citrus. A disastrous instance
was observed in which 2,4-D at 1000
p.p.m. was applied to eradicate a dense
stand of Callicarpa americana, growing
as a weed in a block of Pineapple oranges
on Rough lemon roots. The application
was made in midsummer and care was
taken to avoid spraying the trees direct-
ly. A heavy rain shortly thereafter


washed the 2,4-D down to the Rough
lemon roots and resulted in severe dam-
age and eventual death of the trees. The
same weed in another grove nearby was
treated in the same manner with the
same spray and on the same day. This
grove was on sour orange roots and in
somewhat heavier soil. It escaped any
visual damage. Presumably the differ-
ence in response can be attributed chiefly
to the difference in rootstock,-the
Rough lemon apparently being more sen-
sitive than sour orange.

We wish to express our thanks to the
Chase Investment Company at Winder-
mere, Florida, for their generous co-
operation and assistance in applying the

sprays for the Pineapple and Valencia
tests. Our appreciation is also extended
to Mr. G. F. Randall of Orlando for per-
mitting the use of his groves for certain
of the experiments.
1. GARDNER. F. E. Practical applications of plant
growth substances in horticulture. Proc. Fla.
State lort. Soc. 54: 20-26, 1941.
2. GARDNER, F. E., and COOPER, W. C. Effective-
ness of growth substances in delaying abscission
of Coleus petioles. Bot. Gaz. 105: 80-89, 1943.
L. P. Spraying plant growth substances for
control of the pre-harvest drop of apples. Proc.
Amer. Soc. Hort. Sci. 37: 415-428, 1939.
4. STEWART, W. S., and KLOTZ, L. J. Some effects
of 2,4-dichlorophenoxyacetic acid on fruit drop
and morphology of oranges. Bot. Gaz. 109:
150-162, 1947.
5. STEWART, W. S., and PARKER, E. R. Preliminary
studies on the effects of 2,4-D sprays on pre-
harvest drop, yield, and quality of grapefruit.
Proc. Amer. Soc. Hort. Sci. 50: 187-194, 1947.


Citrus Experiment Station
Lake Alfred

A knowledge of the chemical com-
position or mineral content of irrigation
water is of great importance to growers
because of the known detrimental
effects to plants of highly mineralized
water. Although water from various
sources has been used for irrigating
citrus in Florida for many years little
is known of the actual chemical com-
position of much of the water which is
used. A report made 50 years ago indi-
cated damage to citrus when irrigated
with artesian well water (9). A more
recent report (14) indicated that many
wells in several East Coast districts
were increasing in salt content thus in-
creasing the possibility of damage when
used on groves. Similar increases in
saltiness have been experienced with
municipal water supplies for several
coastal cities (8) (10).

In most areas where irrigation is
required, the annual rainfall is gener-
ally low. Such conditions result in ac-
cumulations of salts in the soil, because
there is little or no loss of the salts
through leaching by rainfall. Since
practically all of the citrus growing
area of Florida receives annually 50 to
60 inches of rain (4) accumulations of
salts are not likely to occur from year
to year. Leaching of applied salts is
also aided by the fact that most of the
soils on which citrus is growing in
Florida is of a very sandy porous na-
ture and easily leached. Since these
soils contain practically no clay which
exhibits exchange capacity, additions
of sodium from salt water does not
destroy their structure thus impeding
leaching as often happens in many
regions using irrigation.
For these reasons the use of irriga-
tion water on citrus in Florida presents
a different problem than found in many
other citrus growing areas. In fact,


water containing greater amounts of
salts can be used under the climatic
and soil conditions found in Florida
than could be used if the climate were
drier and the soils heavier. This was
pointed out in work done by Young (15)
using known concentrations of sodium
chloride solutions on citrus seedlings
growing in pots in the greenhouse. He
concluded that relatively high concen-
trations of sodium chloride alone were
not detrimental to growth.
Previous analysis of irrigation waters
(14) involved only the determination of
the chloride content and a calculation
to the equivalent amount of sodium
chloride. Some preliminary work with
water samples taken in 1949 showed
that the amounts of sodium found were
not sufficient to account for all the
chlorides present, thus indicating the
presence of other minerals such as cal-
cium and magnesium chlorides. This
is to be expected because the mineral
composition of the water will be deter-
mined by the minerals dissolved from
the rock and mineral deposits through
which it passes plus that contributed
from any infiltration by sea water. Sev-
eral reports (5) (10) have listed the
chemical constituents found in waters
from different Florida localities. Most
of these analyses are for municipal
water supplies and relatively less in-
formation is available giving data re-
lated to irrigation supplies.
Thus, for several reasons, a more
complete picture of the composition of
water used for irrigation was felt de-
sirable in order to more correctly evalu-
ate such water. It is the purpose of
this report to list the composition of
waters from widely different localities
which are used for irrigating or for
mixing sprays for citrus.

Collection of Samples
Clean quart mason jars fitted with a
jar rubber and glass top were used to

transport water samples to the laboratory
for analysis. An effort was made to
obtain samples from wells which were
in use, since it is known that a lower
mineral content is often found in wells
which have not been used for several
weeks or months. After the well has
been in use for several hours the mineral
content becomes relatively stable.

Methods of Analysis
The methods of analysis used were of
a type primarily fitted to water analysis.
Several of the methods are relatively
recent developments and will be men-
tioned briefly.
pH measurements were made using a
glass electrode.
Specific conductance was measured in
mhos x 10 5 at 25'C. This measure-
ment is directly related to total dissolved
solids in the water.
Calcium was determined by titrating
an aliquot of the water with versene
(disodium dihydrogen ethylenediamine
tetracetate dihydrate) using ammonium
purpurate indicator (2) (6).
Magnesium was measured by titrating
a portion of the water with versene using
errochrome black T indicator which gives
a value for the total magnesium and
calcium present. By subtracting the
amount of calcium previously found the
magnesium concentration can be found
Sodium was estimated through the use
of a flame photometer (1) (12).
Clli', 'I- concentration was found by
titration with mercuric nitrate using
diphenylcarbazone bromophenol blue
mixed indicator (3).
Sulfate content was measured by pre-
cipitation under controlled conditions
with barium chloride and reading the re-
sultant turbidity with a photoelectric
colorimeter (11).
Carbonates and bicarbonates were esti-
mated by titration with standard sulfuric
acid using phenolphthalein indicator for


the carbonate endpoint and methyl purple
for the bicarbonate endpoint (7).
A qualitative analysis of several of the
wells containing the largest amounts of
dissolved solids was made by a spectro-
graphic procedure.

Relationship of Specific Conductance
and Total Dissolved Solids
Twenty-four water samples represent-
ing the East Coast, West Coast and Cen-
tral Florida were evaporated to dryness
and the resulting salts weighed. The
total dissolved solids in parts per million
thus determined were compared to speci-
fic conductance values obtained with a
conductivity meter. Fig. 1. The rela-
tionship was found to be directly propor-
tional and if the specific conductance in
mhos x 10 5 at 250C. is multiplied by 7
the concentration of soluble salts is ob-



x 800-

6000 -
9 500-
1 400-
F 300-

z0 10


trained directly in parts per million. This
relationship is the same as found in other
areas of the United States where water
analyses are made (13). Since the speci-
fic conductance of a water sample is very
easily obtained (comparable to the time
required for a soil pH determination) it
can be seen that such a measurement is
of great value in rapidly evaluating a
water source. It is probably the best
single index for deciding the advisability
of using water for irrigation in Florida.

Average Chemical Composition of
Water from Nine Florida Counties
The maximum, minimum and average
amounts of the various elements deter-
mined along with pH, total dissolved
solids and calculated amount of sodium
chloride in water from several localities
is given in Table 1. The sodium chloride

300 4000 5000 6000 7000 8000 9000

Fig. 1. Relationship between parts per million total dissolved solids and
conductivity measurements of irrigation water.


content is given simply for a basis of careful consideration of local conditions
comparison with previously published and if a new well is to be drilled a geolo-
figures. As previously mentioned it does gist familiar with local conditions should
not represent a true picture, however, be consulted. Further study of this table
since all the chlorides found cannot be reveals the great variation between lo-
assumed to be sodium chloride, calities in water composition. For ex-
From this table it can be seen that ample on the mainland of Brevard
individual wells within the same locality County there was on the average 1283
vary considerably in mineral content, p.p.m. of chloride ion and 107 p.p.m. of
This is to be expected because all wells sulfate ion whereas in Sarasota County
are not at the same depth and conse- there was only 202 p.p.m. of chloride ion
quently tap different water strata. This as compared to 836 p.p.m. of sulfate. In
great variability stresses the need for one case the water was primarily chloride


No. Parts Per Million
Locality Samples pH T.D.S.2 Na Ca Mg Cl SO, CO, HCO, NaCl

Brevard Co. Max. 8.40 15000 4800 514 635 7745 1200 14 135 12768
Islands Min. 7.50 763 110 62 27 225 34 0 7 371
57 Aver. 8.20k 3106 688 170 108 1432 203 8 105 2349
Brevard Co. Max. 8.40 7217 2100 269 223 3872 230 16 156 6383
Mainland Min. 7.65 1484 269 76 39 605 0 0 7 997
10 Aver. 7.95 2580 624 132 87 1283 107 5 94 2116
Indian River Co. Max. 8.40 1442 260 96 68 527 230 16 159 870
Min. 7.30 833 124 47 46 225 38 6 99 371
38 Aver. 7.79 1099 179 64 57 371 106 12 133 607
St. Lucie Co. Max. 8.30 3570 869 116 110 1494 384 25 299 2463
Min. 7.30 714 90 37 23 151 48 6 90 249
55 Aver. 7.81 1528 295 72 59 538 138 13 137 887
Pinellas Co. Max. 8.40 2280 590 246 67 1626 120 19 228 2681
Min. 6.98 168 0 22 2 18 0 0 10 30
21 Aver. 7.54 887 129 70 25 296 30 9 143 488
Manatee Co. Max. 7.85 2430 360 289 116 822 590 19 164 1356
Min. 7.35 441 0 60 28 18 137 0 35 30
26 Aver. 7.60 1043 58 151 66 162 387 6 129 272
Sarasota Co. Max. 8.20 2280 245 463 152 520 1526 16 170 857
Min. 7.35 644 24 78 50 30 295 0 84 50
14 Aver. 7.54 1314 60 255 96 202 8:36 5 121 333
Charlotte Co. Max. 8.60 5240 1180 241 195 2109 771 16 145 3477
Min. 7.20 1010 158 67 45 302 48 0 48 499
11 Aver. 7.67 2485 468 150 93 975 302 6 100 1607
Lee Co. Max. 7.80 2580 530 130 101 974 379 16 180 1605
Min. 7.30 1554 270 71 61 457 240 0 96 754
9 Aver. 7.59 2185 411 102 87 774 305 11 145 1276
Polk Co. Wells Max. 7.65 221 8.1 37.2 7.1 9.6 2.4 0 144 16
Min. 7.40 168 5.5 29.2 5.6 6.2 2.4 0 108 10
2 Aver. 7.52 194 6.8 33.2 6.4 7.9 2.4 0 126 13
Polk Co. Lakes Max. 7.20 98 9.0 6.4 5.3 18.8 31.2 0 22.6 31
Min. 6.55 35 5.1 1.4 2.6 9.6 16.8 0 3.1 16
9 Aver. 6.93 69 7 4 3 14 23 0 13 23

SArithmetic mean of individual values.
Total dissolved solids calculated from conductivity.


Si o~ o C- oC c C1 w > L-1
1, O tt1 -I N I C>
4 g g o ,c'1 40o

S0 0 -i 1_ !
1 1:V

00 `1 i-C 00 M
0 01 0000

0 ORf i < 0M0-4
N 14 11: oi e= 1- 4 N N -I

Ma t-: "s
bA ~1 h1
% d 00c~

-0 M e e- t

00 C1iO0010
C10 uM 0

e' c':


10 00 CO OS~ 00 Tf OO 0 0 ^
0n ito 0 t t'- 000 .o 00
MCO CO il i-l (M I
c tO M 1-1 1- a N cn CA Q

4 a

Z=$000,- J

,a ~ 4C 0 0
ci .

Cd Cd Uh C
Cd l
S s cl-L^

W W S t3 e w a a

and in the other primarily sulfate. Fur-
ther inspection shows the much greater
mineral concentration in water from
both coastal regions as compared to deep
wells in the inland district of Polk Coun-
ty. As might be expected the lowest
concentration of salts is found in the
lakes of Polk County.
Another perhaps more easily under-
standable way of expressing the mineral
content of water and resultant addition
of salts when added to the soil as irriga-
tion is given in Table 2. This table gives
the pounds of various salts added to an
acre of soil when that acre is irrigated
with one inch of water containing the
average mineral composition for the par-
ticular locality in question. If for ex-
ample you applied an irrigation of two
acre inches using the maximum water
found in SarasotaCounty you would have
added to that acre 414 pounds of sodium
chloride, 162.8 pounds of magnesium
chloride, 50.6 pounds of magnesium sul-
fate, 307.4 pounds of calcium sulfate,
14.1 pounds of calcium carbonate and 62
pounds of calcium bicarbonate or a total
of 1021 pounds of these various salts.
When it is realized how much material
can be added through irrigation the im-
portance of not letting a grove get dry
after irrigation is readily understood.
If 1000 pounds of soluble salts were
evenly distributed through the first 2
feet of an acre of the average sandy soil
by an irrigation, the soil would contain
125 p.p.m. of soluble salts. However, the
average sandy soil will hold only 5 per-
cent water so that the soil solution at
field capacity will contain 2500 p.p.m.
soluble salts. If the soil moisture drops
to 1 percent the soil solution will contain
12,500 p.p.m. soluble salts which is high
enough to injure most plants. Once irri-
gation is started with water containing
considerable soluble salts the soil should
never be permitted to become low in
moisture at least until after a good leach-
ing rain. I


Trend in Salt Concentration of
East Coast Wells
Table 3 records the changes found in
wells from several East Coast areas from
the period 1942 to 1950. More wells
were sampled from 1944 to 1950 and
that data is included separately. In
eight out of eleven areas sampled from
1942 to 1950 there was an increase in
salt concentration. With more samples
taken from 1944 to 1950 six areas out of
12 showed an increase while the other
six areas decreased. In all cases the
increase or decrease was slight and the
trend either way was related to a defi-
nite region. For these wells it would
appear that changes take place rather

Other Elements Found in Water
One of the objectives of this investi-
gation was to determine what other ele-
ments might be present in addition to
the usual constituents. Examination by
spectrographic means of residues from
16 wells showing the highest concentra-
tion of soluble salts revealed considerable
amounts of strontium present in all sam-
ples. A quantitative analysis of one

sample showed approximately 30 p.p.m.
strontium present. The effects of stron-
tium on citrus are not known but it is
known to be toxic to some plants. Experi-
ments have been started to estimate its
effect on citrus. No barium, potassium,
or lithium was present in the samples
examined although these elements are
often present in natural waters.

1. The total soluble salts present in
an irrigation water is probably the best
single index to use in evaluating the
2. The climatic conditions and soil
types in Florida permit the use of water
containing greater amounts of soluble
salts than is ordinarily considered safe.
3. It is essential that, when irrigating
with a high mineral content water, the
soil moisture is maintained as high as
4. Individual wells in the same area
vary considerably in soluble salt concen-
tration and different areas vary as to
the type of soluble salts present.
5. Strontium was found in the water



Brevard Mainland
N. W. Vero Beach
S. W. Vero Beach
Ft. Pierce Farms
Ft. Pierce Vicinity
White City

-57 Wells Sampled from 1942
to 1950

1942 1944

1235 1320






88 Wells Sampled from
1944 to 1950




Wells 1944 1947

3 1263
3 5712
19 2134
6 1765
10 1481
3 1068
4 486
11 611
13 630
8 703
6 633
2 1015






from wells on both the East and West
Coasts of Florida and may or may not
present a hazard to citrus.
6. The increase in saltiness of wells
on the East Coast is slow and confined
to certain districts.

1. BERRY, J. W., D. G. CHAPPELL, and R. B.
BARNES. Improved method of flame photometry.
Ind. Eng. Chem., Anal. Ed., 18:19. 1946:
2. BETZ, J. D., and C. A. NOLL. Total hardness in
water by direct colorimetric titration. Jour.
Amer. Water Works Assoc. 42:49-56. 1950.
3. CLARKE, F. E. Determination of chloride in
water. Anal. Chem. 22:553. 1950.
4. Climate and Man. Yearbook of Agriculture.
pp. 809-818. 1941.
5. COLLINS, W. D., and C. S. HOWARD. Chemical
character of waters of Florida. Dept. of the
Interior. Water Supply Paper. 596-G. 1927.
6. DIEHL, H., C. A. GOETZ, and C. HACII. The
versenate titration for total hardness. Jour.
Amer. Water Works Assoc., 42:40-48. 1950.

7. Official and Tentative Methods of Analysis.
A.O.A.C., p. 640, 6th Ed. 1945.
8. PARKER, G. G. Salt water encroachment in
Southern Florida. Jour. Amer. Water Works
Assoc. 37:526-542. 1945.
9. ROBINSON, M. RReport on fertilizers and
irrigation. Proc. Fla. State Ilort. Soc. 13:140-
145. 1900.
10. STRINGFIELD, V. T. Ground water resources of
Sarasota County, Florida. Twenty-third, twenty-
fourth annual report. Fla. State Geological
Survey. P. 176. 1930-32.
Rapid turbidimetric method for determination of
sulfates. Ind. Eng. Chem., Anal. Ed. 14:119.
Application of flame spectrophotometry to water
analysis. Anal. Chem., 22:667. 1950.
18. WILcox, L. V. Explanation and interpretation
of analysis of irrigation water. U.S.D.A. Circular
No. 784. May 1948.
14. YOUNG, T. W., and V. C. JAMISON. Saltiness in
irrigation wells. Proc. Fla. State Hort. Soc.
15. YOUNG, T. W. Florida Agricultural Experiment
Station. Annual Report. P. 288. 1949.


Florida Geological Survey

All life depends upon water for its
very existence. As an essential to human
life water is second only to the air we
breathe. It is therefore the more de-
plorable that this commodity on which
our existence depends continues to be
wastefully and unwisely used with either
complacent disregard for, or no thought
of, the consequences of such practices.
Periodic deficiencies brought about by
droughts, by local overdevelopment or by
occasional breakdown of the water supply
system may tend to impress upon us the
importance of an adequate water supply,
but as soon as our temporary inconven-
iences are removed we again fail to ex-
ercise discretion in protecting our water
resources. Water is the most valuable
and priceless resource that any commun-

ity, county or state possesses. The short-
age recently experienced by New York
City has quite forcefully focused atten-
tion upon the necessity of an ample water
supply, and this has had a stimulating
influence on Nation-wide thinking about
water resources.
In regions like Florida blessed with
generous rainfall and with formations
adapted to storing it, there is at least
more reason for the prevailing general
idea-and often firm conviction-that
water supplies are inexhaustible and may
be used or cast away without concern as
to the effect on future supplies. Yet
even in these regions where provident
Nature has been extremely generous,
there is evidence of an increasing con-
cern about the adequacy and permanence
of water supplies. This awakening has
come about gradually the hard way-by
actual experience. With rapid increase
both in population and in industry great-
er and greater demands for water are


made, and in supplying these increasing
demands arresting problems have arisen.
Everyone should realize that water is
an exhaustible resource and should in all
uses treat it accordingly. In providing
water there should be rather clear ideas
as to the source to be tapped, the develop-
ment of the well field, the movement of
water underground into the area, and the
general character of water that may be
obtained. With the accumulation of such
information and the assimilation of such
data it is possible to more intelligently
and satisfactorily locate wells, let con-
tracts for drilling, develop the supply,

toyrC'^ S7 .;^ ^B

and guard against contamination as well
as possible infiltration of salt water.

Source of Our Water Supply
A very general and popular explana-
tion of the source of artesian water in
Florida is that it originates in the moun-
tainous regions of states to the north,
and in spite of all that has been said
through the years to the contrary, this
idea still persists. Except for those por-
tions of the State bordering Georgia and
Alabama, all the ground water in Florida
comes from rainfall within the State,
and even in northern and western Flor-

EXPLANATION-Contour lines represent approximately the height, in fee.. to --
which water will rise with reference to mean sea level in tightly cased well i o (l
that penetrate the principal artesian aquifer. Contour intervals 20 fetl.
Stippling Indicates area of flowing wells. '

Plate I. Map of Florida Showing Piezometric Surface of Main Artesian Aquifer
and Area of Flowing Wells.


ida the ground water originates in local
rainfall, but here it is supplemented by
contributions from southern Georgia and
Alabama through contiguous surface and
subsurface formations. The formations
in the northern mountainous regions are
vastly different in age and character from
those at or near the surface in Florida
and, if the former are present in our
State, they lie at great depth with no
influence on or connection with the
artesian reservoir. Furthermore, the
water from these deeply buried forma-
tions is known to be highly charged with
mineral solids and too salty for public
and domestic use.

Geology of Florida
History records that Ponce de Leon
was in search of the "Fountain of
Youth." Without doubt some early ex-
plorers had related fantastic and fasci-
nating stories about the large springs of
this newly discovered world which so
intrigued Ponce de Leon that he felt
compelled to search for this land of
"Eternal Youth." So it may be inferred
that hydrology played a leading role in
focusing world attention to this portion
of the United States.
Be that as it may, Florida does have
an interesting geological history. All
of the formations present at the surface,
and to a considerable depth, are of sedi-
mentary origin and geologically speaking
are recent or young. Underlying these
formations, however, we know there are
still older sediments that rest on older
rocks, some of which are metamorphic
and some igneous in character. This
rock sequence indicates that Florida has
been here since quite ancient time.
To better understand the occurrence,
movement and development of ground
water one must turn to geology as the
source of help. There is a very close
relationship between the occurrence of
ground water, the configuration of the
ground surface, and the character and

structure of rock formations, all of which
influence the accumulation, rate of move-
ment and direction of flow of water
under ground. Let us consider briefly the
geology of Florida, and limit the discus-
sion to those formations most important
to water supply.
All of the surface or exposed forma-
tions in Florida are included within the
latest major division of geologic time,
termed the Cenozoic Era, meaning more
modern time. In Florida there is com-
plete representation of each series in this
era from the oldest to the youngest. The
most important of these in relation to
water supply are: 1) the Eocene, includ-
ing the Ocala and older limestones, 2)
the Oligocene, mainly the Suwannee and
Marianna limestones, and 3) the Miocene,
of special interest because of develop-
ment in peninsular Florida and the local
names of Tampa limestone and Haw-
thorn formation. Also the more recent
Pliocene and Pleistocene formations,
since these are of importance, especially
in western Florida and along the lower
East Coast.
The principal artesian water forma-
tion, or aquifer, is the Ocala and the
older Eocene limestones. It is from these
limestones that the great volumes of
water are derived in peninsular Florida.
In earlier literature the Ocala limestone
was mistaken for the Vicksburg lime-
stone, named from its typical exposure
at Vicksburg, Mississippi. This name is
still applied incorrectly by some citizens
of the State, although the term Ocala
limestone has been used many, many
years, and has here replaced the term
"Vicksburg" in scientific usage. Well
drillers are familiar with the Ocala lime-
stone and are quite proficient in deter-
mining when it has been penetrated,
since the limestone is usually fairly soft,
granular and white to cream-colored,
often full of fossils. These Eocene lime-
stones are known to underlie all of Flor-
ida with the possible exception of the


extreme western portion of the State, IS
and here the lack of subsurface data may
account for its apparent absence or its -
having not been recognized. 2
Lying immediately above the Ocala
limestone is a group of Oligocene lime- @
stones to which appropriate names have a3
been given, and all have physical charac- a
teristics quite similar to the Ocala lime- S
stone, except the Marianna, which is U -
finer grained but resembles in many re-
spects the Ocala limestone in that it is a4
soft, cream-colored and generously fos- "
siliferous. The Byram marl is of local o
occurrence and does not play a prominent -
part in relation to water supplies, but 0
the Suwannee and Flint River limestones 0 co +S
are good aquifers. These limestones are
rather hard, white to cream-yellow, and
quite pure, the calcium carbonate con-
tent being comparable to that of the H CI -
Ocala limestone. It is the Suwannee
limestone that yields the generous supply
of water developed by the City of St.
Petersburg and is currently being con-
sidered as a source for the entire Pinellas 0
Of the Miocene formations, the Tampa
limestone and Hawthorn formation are E
of most importance, because of their wide
distribution and general characteristics. o
The Tampa limestone is yellowish in z
color, fairly hard, and less pure than the
Suwannee and Ocala limestones. It often 4
contains as much as 25 percent silica, .
some alumina and ordinarily very little 0
magnesium. This limestone upon weath- o
ering, therefore, leaves quite a residue
of insoluble materials. It is, however, Q o
an important acquifer. E-
The Hawthorn formation varies from E t
a rather pure to a phosphatic limestone -t S
with large percentages of sand, marl
and clay. In some parts of the State it a
is largely made up of thick beds of clay
and sandy clay. Under such conditions & g
it acts as an impervious bed, confining C *
the water in the underlying limestones 4 P4 P
under artesian pressure. It contains

I __ I

Alachua formation

Sand, clay, and phosphate.

Bone Valley formation 50 Sand, clay, and phosphate.
Buckingham marl 45 Calcareous clay.
Sand, shell, and marl. Yields water to
Caloosahatchee formation 50 shallow wells. Some of the water is highly
Charlton formation 60 Calcareous clay and impure limestone.
Citronelle formation 250 Sand, gravel, and clay. Yields water to
shallow wells.

Tamiami formation

Sandy limestone to nearly pure quartz
sand. Important source of water to shal-
low wells.

Sandy shell marl containing clay. Yields
Duplin marl 50 water to shallow wells and in part ar-
Shoal River formation 170 Fine micaceous sand and sandy clay.
0 tC Sandy limestone and sand with shell.
r_ Chipola formation 56 Yields water to shallow wells, in part ar-
_ ___ tesian.
S C Interbedded sand, clay, marl, and lime-
SS stone, with lenses of fuller's earth. Im-
S Hawthorn formation 500 portant source of water, in part artesian.
SLocally the water is highly mineralized.

Tampa limestone

Limestone and sandy limestone, in places
dolomitic. Important source of water,
much of which is under artesian pressure.
In local areas near coast water is highly




Hard, resonant limestone to soft, granular
& Suwannee limestone 100 limestone, containing some silica. Import-
i ant source of artesian water.

S2 Flint River formation Sandy and pebbly limestone and calcareous
O- (Northwest Florida) 100 dirty sand. Locally silicified.
Byram limestone 40 Limestone, sandy limestone and some
clayey beds. Limited areal extent.
Chalky limestone. Locally an important
Marianna limestone 30 source of water in Jackson, Holmes and
(Northwest Florida) Washington counties.
Predominantly porous limestone. Import-
ant source of water, most of which is under
Ocala limestone 360 artesian pressure. In local areas the water
is highly mineralized.
Chalky limestone containing some gypsum
Avon Park limestone 650 and chert.

Crystalline limestone, argillaceous lime-
Eocene Tallahassee limestone 650 stone.
Chalky limestone locally containing gyp-
Lake City limestone 500 sum and chert.

S Oldsmar limestone 1,200 Predominantly limestone but contains some
a gypsum and chert.
Salt Mountain limestone 200 Soft, chalky limestone.
s (Northwest Florida)

0 Cedar Keys limestone 570 Hard limestone.
Paleocene B Brittle, gray to black clay.
SPorters Creek formation Several
(Northwest Florida) hundred
-itr -o-e

*Water in these beds combine with the water in the Ocala limestone.
Prepared by: Florida Geological Survey, P. 0. Drawer 631, Tallahassee, Florida.

After CooKe.


varying quantities of water and in some
sections is important. It is the phos-
phatic limestone portion of the Haw-
thorn formation that yields water in
some areas so high in fluoride content
that it is detrimental to tooth enamel in
The several formations grouped col-
lectively under Pleistocene and Pliocene
are all water-bearing, and water from
these surface or near-surface forma-
tions is being developed extensively at
present, especially in the southern por-
tion of the Florida Peninsula where the
deeper lying artesian water is generally
quite salty. These formations consist
of limestone, shell marl, coquina and
sand. Ordinarily the quality of the
water in these upper formations is bet-
ter than that in the deeper artesian
aquifers, but the quantity is far less.
One exception, however, is the Tamiami
formation of southern Florida from
which Miami and other cities of Dade
County get copious water supplies. Ac-
cording to the United States Geological
Survey, the Tamiami formation is "one
of the most productive aquifers in the
In western Florida one of the best
water supplies in the State is obtained
from sand. At Pensacola, for instance,
wells are about 250 feet deep and the
water is almost as soft as rain water,
with a mineral solids content of only 41
parts per million. In some parts of
Florida the water from these shallow
formations is high in iron, causing ob-
jectional staining.
Piezometric Surface in Florida
Since its establishment in 1907, the
Florida Geological Survey has cooper-
ated with the United States Geological
Survey in geologic and ground-water
studies. During the past twenty years
these studies have centered almost
entirely on ground water. This re-
search has given us much practical in-

formation about the geology, the char-
acter and capacities of the several
formations, also the direction of flow
and rate of movement of ground water.
These studies have enabled us to con-
struct a map showing the height above
sea level to which water will rise in
wells that penetrate the artesian forma-
tions. To construct such a map it is
necessary to measure the depth to water
-or to obtain pressure head in areas of
artesian flow-in wells throughout the
State, and to know the elevation of each
observation well. With this informa-
tion it is possible to plot the wells on
a map and to show by contour lines the
surface to which water will rise from a
given formation, or group of formations
acting as a hydrologic unit. This is
called the piezometric surface. See
Plate I.
This map is most practical. With it
the well driller can, with a large degree
of accuracy, estimate the level at which
water will stand above sea at any local-
ity along a given contour, and from this
determine the best type of pump in-
stallation for the most satisfactory job.
The map also shows the areas of "piez-
ometric highs," as for instance, the one
in Polk County which is the principal
source for artesian water in central
and southern peninsular Florida. These
piezometric high areas are also termed
recharge areas, while those where such
surface is low are called discharge
areas. Furthermore, the map readily
indicates the general direction of
artesian water movement, which is more
or less perpendicular to the contours,
moving from high to low contours. And
finally the map outlines the areas where
the piezometric surface rises above the
land surface or the area of artesian
flow. Unfortunately, within this area
the artesian water is very highly
charged with mineral solids, in some in-
stances too high for use.


Factors Affecting Florida's Water
The source of the abundant water
supply in Florida is rain. Variations in
rainfall bring about periodic droughts
and floods. During droughts we become
alarmed about the adequacy of the
water supplies, during floods we too
eagerly dispose of excesses as rapidly
as possible. This excessive, rapid dis-
posal by drainage, without due consid-
eration of needed storage basins or
reservoirs to hold the excess for release
in time of low supply, has undoubtedly
contributed to some of the problems
now confronting the State.
Glancing over the rainfall record of
the United States Weather Bureau,
1937-50, or the last 13 years, it is seen
that the average annual rainfall for
Florida was 55.37 inches, the lowest was
43.17 inches in 1938, and the highest
was 72.37 inches in 1947. In 1949 there
were only 50.13 inches and in the first
half of 1950 (January-June), only 15.41
inches were recorded. Evidently, the
deficiency beginning in 1949 is continu-
ing in 1950 with even greater severity.
Although Florida does have a high aver-
age rainfall, the State does suffer
droughts sufficiently severe to cause ex-
tensive crop damage, largely because of
the highly seasonal character of rain-
fall. Low relief and very porous soil
conditions are conducive to high absorp-
tion and low run-off. Evaporation is
excessive in Florida and this together
with transpiration accounts for an
enormous volume of water loss.
When surface water levels are high
there arises a clamor for drainage and
water so disposed of is lost and not
available as a backlog in the dry period
which is sure to follow. During the
boom of the 1920's Florida literally
went through a drainage spree. There
just was not enough naturally dry land
for all the projected subdivisions, so
drainage was resorted to with abandon,

the ultimate effect on the welfare of the
State was never considered. To over-
come the harmful effects of over-drain-
age, consideration should be given to
the construction of baffles, or retaining
structures, to control the run-off and
permit the impounding of as much of
the water as safely possible. This could
later be released and used.
The 1950 United States Census
records an increase of 44 percent in Flor-
ida's population during the decade 1940-
50, while the national gain was 11 per-
cent. Florida indeed is growing rapidly
in population, in winter tourist popula-
tion and in new and expanding industries.
With this development has come such in-
creased demands upon our water sup-
plies as to cause grave concern in some
areas. As example, salt water encroach-
ment in the Pinellas Peninsula has been
caused by overdevelopment for munici-
pal use and irrigation purposes; as a
consequence that region now draws
large quantities of water from the
Odessa-Cosme area in Hillsborough
and Pasco counties, and plans are now
under consideration for further expan-
sion. Salt water encroachment prob-
lems have also confronted Fort Myers,
Tampa, Panama City, and Pensacola on
the west coast, and Fort Pierce, Daytona
Beach, and a strip along the east coast
from St. Augustine southward. As a
result, attention is being given to de-
velopment of water supplies from the
more shallow formations, but the search
for such shallow supplies has not al-
ways been successful. However, the
salt content of the artesian supply has
not entirely prevented its use for irriga-
tion, for many artesian wells are used
for this purpose even though the water
may be too saline for domestic, munici-
pal or industrial purposes.
Large industries have in recent years
moved into Florida, especially the pulp
mills, and these mills use tremendous
volumes of water. Problems have de-


veloped in those areas, but so far have
been met quite satisfactorily. Mineral
industries also use quantities of water
in processing their products. Air con-
ditioning is another factor causing large
drafts. Last but not least, more and
more water is used for irrigation.
In February, 1950, the United States
Geological Survey tabulated an estimate
of the consumption of ground water in
Florida as follows:
Gals. per day
Public supplies serving
100 or more people......160,000,000
Industrial supplies..........200,000,000
Agricultural supplies ....100,000,000
Domestic supplies............ 40,000,000

Total ............................ 500,000,000
This figure of 500,000,000 gallons of
water per day is impressive and should
cause everyone to think clearly and plan
wisely when expansion is contemplated.
This is particularly true in those areas
where over-draft can cause the infiltra-
tion of salt water. Pollution in some
regions, too, has caused grave concern.
Such pollution is the direct consequence
of natural drainage, drainage wells, the
disposal of storm waters, sewage and
industrial waste directly into forma-
tions from which potable ground waters
are obtained.
However serious ground water prob-
lems may be in some areas, there is still
room for optimism on the whole. In this
the following, quoted from Information
Circular No. 3, Florida Geological Sur-
vey, "Ground Water in Florida" by H.
H. Cooper, Jr., and V. T. Stringfield of
the United States Geological Survey, is
most pertinent:
"The consumption of 500 million
gallons of water a day is, of course,
a heavy draft on the ground-water
resources, but this draft should not
be a cause for concern in regard to
the State as a whole when it is real-

ized that the ground-water reser-
voirs are naturally discharging
many hundreds of millions of gal-
lons of water a day, much of which
can be salvaged and used whenever
it is needed. The tremendous dis-
charges of Florida's large limestone
springs, which rank among the
largest in the world, forcibly dem-
onstrate the large capacity of the
ground-water reservoirs. The aver-
age flow of Silver Springs alone is
equal to the estimated total con-
sumption of ground water in the
And too, large quantities of water yet
untapped through central, northern and
western Florida are available for the
industrial future. The problems, how-
ever, that have developed in certain
more or less limited, or local portions of
Florida must certainly be taken as
warnings that there is a limit to the
yield of potable water, and learn from
such warnings to develop and conserve
supplies. To do this there must be con-
tinuous study of the occurrence of
water, the character of water-bearing
formations, the depth from which sup-
plies can be most successfully obtained,
the possible capacities of such forma-
tions, and other related factors. Studies
of this character are in progress by the
Florida Geological Survey in coopera-
tion with the United States Geological
Survey. General State-wide studies and
more detailed studies in particular
areas or counties are in progress.
In summary it can be said that Flor-
ida is fortunate in its water resources.
Its rainfall is one of the highest, and its
formations have maximum absorption
capacity. With'all the assistance Nature
has so generously bestowed upon Flor-
ida with respect to our natural re-
sources including water supplies, we
must learn to utilize them wisely and
provide specific controls through which
conservation would become a reality.



Does Irrigation Pay? This question
has been asked many times by Growers
located in the Ridge Citrus Producing
area of Florida. If it does not pay,
there has been millions of dollars very
foolishly spent in the Ridge area, espe-
cially in the past two years. There are
two methods of irrigation used in this
area I am discussing. First, is with
permanent installation of pumps with
power units, using underground mains
or conductor lines and either overhead
sprinklers or portable sprinkler or
flooding lines. This type requires
greater initial investment with less
operational expenditures. The second
type is with portable pumps and power
units and portable conductor and dis-
tribution pipe. With a source of water
available, this type of unit can be
moved from property to property, there-
by on an acreage basis reducing the
initial investment but, increasing the
operational expense. This method is
used by many in the Ridge Section
which has many lakes.
Do you know that many Growers who
were dependent on Portable Irrigation
during the past spring and summer,
have more money invested in the pres-
ent crop for irrigation than all the
other production costs combined? Yes,
when a property is far removed from a
source of water, portable irrigation cer-
tainly does deplete the bank roll fast.
This is true even if you own the equip-
ment and not just when you hire it
done. In addition, it is a job which has
no end until it rains. When will it rain
is the sixty-four dollar question.
In my opinion there are two types of
irrigation. One is "Preventive" which
implies not allowing the tree to develop
a tight wilted leaf condition or soft

fruit and the other is "Curative." This
type is used in salvaging a crop or pre-
venting mortality of the trees.
It is bad, but true that many Growers
never plan on irrigation until it gets
dry. Then those without irrigation get
panicky and will pay virtually any price
to obtain water. Unfortunately, in
many cases this type of irrigation pre-
sents the greatest gamble.
My initiation to portable irrigation
was with a worn out Buick motor and a
low head centrifugal pump. The suc-
tion was a 22-foot length of 6-inch well
casing. There were 400 feet of 6-inch
28 gauge galvanized slip joint pipe for
conductor line and 2,000 feet of 4-inch,
28 gauge slip joint pipe for conductor
and distribution line. The distribution
was by the flood system. I had many
experiences in attempting to keep water
on the tops of some of those hills or
preventing washing on the hillsides. Of
course, keeping pipe together going up
some of the steep grades sometimes
produced a problem. The principle re-
quirement then to operate that type of
unit was the "Patience of Job." If we
had the maximum of luck, we put water
on part of ten acres in four twelve to
fourteen hour days. As usual, during
most dry periods we were working
around the clock.
During the late thirties after two
successive dry Springs with very little
irrigation and much hauling of water
in barrels to groves, some decent port-
able irrigation equipment began creep-
ing into the picture. The pumps and
power units were some better but the
big improvement was in portable pipe.
This was known as "Lock Joint Type."
It was fourteen gauge zinc coated steel
with enlarged or bell type female end.
Inside the female end was a rubber
gasket. This gasket grew tighter as


water flowed from the pump. Protrud-
ing from the female end were two or
four receptacles so arranged that when
the lugs, located on the male end, fitted
into these recesses and the pipe was
slightly turned, it locked. In addition
to being virtually leak proof, under
pressure, and slightly flexible, in the
event of a power unit stopping and the
foot valve on the pump suction not seat-
ing there would not be a vacuum cre-
ated and causing the pipe to flatten.
This was the case with slip joint pipe.
The main trouble with that zinc coated
steel pipe which was in sixteen foot
lengths, was its weight. One man
could carry it but with great difficulty.
During the war years with a scarcity of
labor, this presented an acute problem.
The labor problem and the increased
use of aluminum after World War II
was the next important step in Portable
Irrigation. The production of portable
aluminum pipe began to appear in this
territory. This was a definite improve-
ment. Not only a labor saver, which
was greatly needed, but due to less pipe
friction more water was pumped with
less power through the same size pipe.
With this type pipe, using 4-inch
sprinklers one Grower's daughter in
our organization handles the moving of
the sprinkler lines by herself.
Along with aluminum pipe there de-
veloped more careful selection, by the
buyer and seller, of the pump and power
unit required for that particular job.
In the past a Grower bought a pump
and obtained a power unit of some
description and hooked them up. The
power unit might gain maximum effici-
ency at 2,400 RPM and the pump at
1,600 RPM but it didn't make a great
deal of difference. The main object was
to have at least some water flowing at
the end of the pipe.
At the present, one sees high head
pumps, which pump a great deal of
water with high pressure against much

pipe friction and terrain elevation.
Power units pull these pumps direct
connected or belt driven. Most of them
have a clutch which allows easier start-
ing of the power unit and priming of
the centrifugal pumps.
There are some Growers with prop-
erties not located near lakes which do
the following: Drill a well and mount
a turbine pump on the well with a gear-
head and power take off shaft extended.
They put the same size pump on the
various wells. Then they use one power
unit and their portable pipe on all three
or four properties.
In selecting equipment for use in
portable irrigation much thought should
be given to the subject. Such as height
of property above level of water, size
acreage, and distance from source of
water. I am assuming, that you would
want the most economical unit to oper-
ate. Beginning with a smaller unit to
be used on plots located on a lake con-
sisting of ten acres or less. In this
situation, a small power unit with small
high head pump that will supply a
minimum of 300 GPM with a maximum
head involved, is sufficient. I would sug-
gest 6-inch aluminum conductor lines
and 4-inch aluminum sprinkler lines.
This unit, after assembling, can easily
be operated by one man. This type of
grove would usually have a rather steep
slope and therefore, you would not want
very much water flowing. With less
water, the soil will absorb it without
washing. Your sprinkler lines would
be approximately 330 feet in length.
One 330 foot line would be operating
while the other was being moved.
The next size unit would be a high
head pump that would deliver 700-750
GPM with comparable power unit that
would deliver the maximum of water
required with a maximum of head to
operate against. The optimum conduc-
tor line would be 8-inch aluminum, or
with less head, 6-inch would suffice. The


sprinkler lines would be 5-inch alumi-
num of 660 feet in length per operating
line. Where there is a maximum head
to be operated against or where it is
advantageous to use 990-foot sprinkler
lines, I would suggest 1000 or 1100
GPM pump with power unit. The Big
Bertha of Portable Irrigation is the
1,500 to 1,600 GPM high head pump and
power unit to match. This would use
8-iich aluminum conductor pipe with
6-inch sprinkler lines either two 660-
foot operating lines or one 1,320-foot
operating line. This unit is used to a
good advantage where a number of 10
Or 20-acre tracts can be irrigated from
one source of water. In addition it can
furnish water to properties up to one
and one-half miles distance from a
source of water and against extreme
heads. Actually you are operating two
conventional 660-foot lines with just
one pump and power unit. The time
factor is increased by inserting crosses
with valves into the conductor lines.
With the use of one additional sprinkler
line to change from one property to an-
other the pump never ceases operation.
For example, when crosses with valves
are inserted in the conductor line while
it is being assembled eighteen or twenty
different blocks spread over a long dis-
tance, can be irrigated without ever
stopping the pump. Of course, it isn't
economical to use on small individual
acreages due to cost of moving and
setting up.
There are two factors of great im-
portance in Portable Irrigation. They
are the method employed in moving and
time factor between moves. They work
very closely together. It is always like
working a jigsaw puzzle and shortage
of pipe is usually the "fly in the oint-
ment." Avoid successive moves where
all the pipe you have is required. It is
indeed difficult to always have enough
pipe for'any type of portable irrigation.
:Due to pipe scarcity during extended

periods of drouth a bit of trading by
various organizations has proven bene-
ficial to all involved. In other words
when one organization is set up near a
property of another, the organization,
so set up does the irrigation for another
or at least rents the pipe for that prop-
erty to be irrigated prior to its being
In the method of moving, is the all
important question of what type of
equipment to use in hauling the pipe.
This depends on distance between
moves and many times what is available
to use. Almost every conceivable type
of equipment is used on the Ridge.
Everything from mules and sleds to
semi-trailers. One organization comes
up with a useful piece of moving equip-
ment and it is quickly copied by others.
The time factor mentioned above is
all important. This means primarily do
not over extend yourself. During ex-
tended periods of drouth properties
have to be irrigated even six or seven
consecutive times. Therefore, to pro-
tect your interest or the Growers' inter-
est, you must be able to repeat the
operation prior to the property being
depleted of moisture. If you do not,
the previous irrigation or irrigations
have gone for naught and much is lost.
Make a survey of your needs, have a
reputable organization advise you as to
your requirements, usually add 25%
average on these requirements and you
will be in position to have an economi-
cal operation.
There are indications that the Port-
able Irrigation in the Ridge area is be-
ing improved every year. This improve-
ment is being made by semi-permanent
installations. This is where growers
are putting in an underground per-
manent conductor line by a cooperative
plan. Portable pumps and sprinkler
pipe is used. This is an excellent opera-


tional saving and reduces the time fac-
tor, as it is moving of conductor line
which is the bottleneck.
I think we are yet in the dark ages on
Portable Irrigation. Much has been
done in its development during the past
two or three years. Yet more has to be
done in lowering the cost per acre inch
of water applied to the citrus groves.
More Growers are thinking in terms of
Water Conservation which is vitally

necessary. More efficient facilities will
have to be developed in reducing appli-
cation costs. More research work is
necessary in order that water is not
wasted. This operation of Portable
Irrigation will definitely develop fast if
the next ten years are as generally dry
as in the past ten. In closing, I urge
you to start thinking and doing some-
thing about this all important problem
of Portable Irrigation.


U. S. Subtropical Fruit Field Station

Previous reports on the boron nutri-
tion of citrus have been concerned
c iefly with deficiency and toxicity re-
slonses. The objective of the present
s udy was to maintain trees at differ-
ent levels of boron between these two
e trees and to observe any differences
t at occurred in regard to general
g owth pattern, mineral composition of
tle leaves, and fruiting behavior.
Twelve young Valencia orange trees
which were budded on Routh lemon
s ock, were planted into 50-gallon con-
t iners filled with white quartz sand.
Beginning May 28, 1947, complete
n itrient solution was applied twice
weekly at the rate of 2 to 3 liters per
application. The rate of boron used in
tle nutrient feeding was the only dif-
fErential variable for the succeeding
three years. The lowest boron level
was that which was supplied as im-
purities in the C.P. salts and the lake
water used as a water source. A medium
b 2.) p.p.m. were maintained as the other
two treatments. Four trees received

each treatment. Water was applied be-
tween nutrient feedings in amounts
that induced leaching Further details
of the method of culture are presented
in a previous article (6).
Leaf samples were collected each
year and analyzed for various major
and minor elements. Trunk diameter
measurements were made semi-annual-
ly. Fruit was allowed to develop dur-
ing the third year and was analyzed for
total soluble solids, ascorbic acid, and
citric acid.
Results and Discussion
In general, excellent growth was
made by all trees. The size attained
was equal to or greater than identical
trees growing in soil adjacent to the
plots. All growth was nearly normal
in appearance except that the low-boron
trees showed mild deficiency symptoms
in the foliage (4) during the fall months
of the second year, and the high-boron
trees showed mild toxicity symptoms of
occasional tip burn and yellow spots
(1) throughout the test period. These
symptoms were more pronounced during
1948, when the mean total boron content
in dry leaf samples was 386 p.p.m., than
in 1949 and 1950 when it was about 265.


The high boron trees showed some ten-
dency toward forming a less compact
top than the others. They had fewer,
but larger, branches and a more open
character. The mean tree size was
nearly identical in all three treatments.
This is indicated by the cross-sectional
trunk area measurements in table 1.
The leaf samples collected on the
first three and last sampling dates
shown in table 1 were mature spring-
flush leaves. A broad range in the B
concentration within the leaf was in-
duced and maintained. This range was
over 24-fold in the summer of 1948 and
over 10-fold in the summers of 1949
and 1950. The differences in the other
elements in these mature samples are
relatively small. Phosphorus tends to
be present in slightly greater concen-
trations when B is low. Such a rela-
tionship has previously been found with
sunflowers (2).
Three samplings were made from
young leaves, which were developing in
the fall at the time that a crop of fruit
was maturing. Under these conditions
the difference in the P concentration
was greater than with mature leaves,
although the difference appeared to
diminish as the leaf approached matur-
ity. The concentrations of the three
base elements, K, Ca, and Mg were also
influenced in these younger leaves.
When B was supplied in a very limited
amount Mg had a tendency to enter the
leaf in greater amounts, and reciprocal-
ly, K in lesser amounts. Calcium ap-
pears to have been depressed at the
highest boron level. Here again it ap-
pears that these differences are perhaps
temporary and tend to diminish as the
leaf grows older.
Nitrogen, manganese, copper, iron,
and zinc do not appear to have been in-
fluenced in any way by the variation in
boron supply. Sodium was determined
on the same collections for which iron
values are shown and showed no differ-

ences which were attributable to the
rate of boron supply.
From 10 to 15 pounds of oranges were
produced by each tree during 1949.
These were picked and analyzed on
February 6, 1950. No systematic dif-
ferences were found in the yield, fruit
size, rind thickness, juice content, or
percentage of total soluble solids and
citric acid in the juice. The only dif-
ference that was consistent in all four
replications was a reduction in the
ascorbic acid content of the juice in the
low-boron trees. This treatment aver-
aged 49.8 mg. per 100 ml., as against
57.0 and 54.9 for the medium and high
boron treatments, respectively. This
response may be indirectly attributable
to the boron suply, however, and more
closely associated with the higher level
of phosphorus in the low-boron trees.
This latter relationship was found to
exist under orchard conditions when the
leaf phosphorus was increased without
changing the boron status of the trees
The literature on boron nutrition
shows several cases with various plants
of a lack of growth response to a dif-
ferential supply of this element between
the limits of deficiency and toxicity
levels. On the basis of this limited
study with Valencia oranges, citrus
seems to be no exception to that rule.
Apparently normal trees can be grown
with very limited applications of boron
if it is supplied at frequent intervals.
Likewise, applications of boron in
amounts which produce mild toxicity
symptoms do not seem to interfere ap-
preciably with the functioning of the
plant. The evidence presented is the
first to show the relatively small effect
of rather large variations in the boron
content (maximum range 16 to 386
p.p.m.) of citrus on growth, fruiting,
and the concentration of other mineral
elements in the leaves.- A similar range
(30 to 305 p.p.m. boron) in mature Va-


Boron Mean trunk Mean leaf
applied X-section weight
(p.p.m.) (cm. 2) (mg.)

Percentage of leaf dry matter

P.p.m. in leaf dry matter

N P K Ca Mg B Mn Cu Zn Fe

0.00 3.08 193 2.82
0.50 3.07 176 2.78
2.00 2.73 193 2.71

0.00 4.89 274 2.91
0.50 4.75 272 2.89
2.00 4.49 330 2.81

0.01 14.56 364 2.26
0.50 14.77 358 2.25
2.00 13.89 389 2.15

5 months

6 months

6 months

1 month

2 months

4 months

5 months

414 2.15
365 2.23
379 2.12

458 2.44
419 2.38
431 2.34

0.01 18.13 506 2.30
0.50 18.18 454 2.35
2.00 18.36 477 2.31
0.01 20.52 304 2.35
0.50 20.67 314 2.20
2.00 20.87 326 2.27

0.150 1.84 2.95 0.395 41 42
0.171 1.77 2.98 0.360 90 47
0.136 1.79 2.98 0.352 117 41

0.164 2.86 2.42 0.194 16 33
0.156 2.84 2.55 0.194 i44 44
0.161 2.92 2.52 0.202 386 46

0.133* 1.84 2.68 0.288 25 31
0.121 1.72 2.84 0.242* 93 34
0.112 1.99 2.70 0.267 263 30

0.178** 1.84** 2.61 0.512** 17 24
0.147 2.13 2.69 0.442 58 35
0.146 2.15 2.20** 0.444 130 25

0.175** 1.82** 2.90 0.524** 20 28
0.140 2.04 2.74 0.435 67 32
0.137 2.25 2.50** 0.421 158 29

0.157* 1.65 2.98 0.450* 24 44
0.133 1.68 2.98 0.400 78 45
0.138 2.03** 2.55** 0.398 168 36
0.119 1.48** 2.46 0.349 25 43
0.117 1.80 2.54 0.312 104 38
0.114 1.78 2.41 0.351 262 40

8 -
9 -
8 -

8 74 -
9 80
8 64

14 47 83
14 41 83
13 43 76

14 29 66
14 24 68
14 25 65

13 29 -
15 36 -
14 36 -

13 29 -
14 28 -
13 33 -
12 34 -
12 33 -
11 32 -

L.S.D. between
any two means @ 0.05
(@ 0.01

N.S. N.S. N.S. 0.020 0.22 0.27 0.040 2.7
0.027 0.30 0.36 0.053 3.6

N.S. N.S. N.S. N.S.

6 Significant difference.
"' Highly significant difference.

Sampling date
and leaf age




lencia orange leaves was found in a
recent survey (3) of 75 commercial
orchards in the major citrus producing
areas of the United States.

Young Valencia orange trees were
grown for three years in large outdoor
sand cultures on complete nutrient solu-
tions that varied differentially only in
the amount of boron. Three rates of
boron were applied to single-tree plots.
The plots were replicated four times.
No difference in tree size resulted
from the differential treatments.
Rather large differences in the boron
content of the leaves were induced. The
low-boron plants showed mild foliage
deficiency symptoms during the second
year but not in the first or third years
of growth. The high-boron plants
showed slight leaf symptoms of toxicity
throughout the three-year period.
Mature leaves showed virtually no
differences in mineral composition other
than the 10- to 24-fold difference in
boron. Phosphorus tended to be present
in slightly greater concentration when
boron was low.
Young leaves showed this same rela-
tionship with phosphorus in a more pro-

nounced manner. When the boron sup-
ply was low, potassium accumulation in
the leaf was retarded and magnesium
accumulation accentuated. The rate of
calcium accumulation was depressed at
the highest boron level. These differ-
ences appear to diminish as the leaf
approaches maturity.
The only consistent difference in the
quality of the fruit produced during the
third year was a slight reduction in the
ascorbic acid content in the low-boron
1. CAMP, A. F., and FUDGE, B. R. Some symp-
toms of citrus malnutrition in Florida. Fla.
Agr. Exp. Sta. Bull. 335. 1939.
2. REED, H. S. A Physiological study of boron
deficiency in plants. Hilgardia 17: 377-411.
3. REUTHER, W., SMITH, P. F., and SPECHT, A. W.
A comparison of the mineral composition of
Valencia orange leaves from the major producing
areas of the United States. Proc. Fla. State
Hort. Soc. 62: 38-45. 1949.
4. SMITH, P. F. and REUTHEn, W. Observations
on boron deficiency in citrus. Proc. Fla. State
Hort. Soc. 62: 31-37. 1949.
5. SMITH, P. F., REUTHER, W., and GARDNER, F. E.
Phosphate fertilizer trials with oranges in Florida.
II. Effect on some fruit qualities. Proc. Amer.
Soc. Hort. Sci. 53: 85-90. 1949.
6. SMITH, P. F., and REUTHER, W. The response
of young Valencia orange trees to differential
boron supply in sand culture. Plant Physiol. 26:
(In Press). 1951.


Its Occurrence in Florida Citrus

Bureau of Plant Industry, Soils, and
Agricultural Engineering, United
States Department of Agriculture

In 1945 G. H. Godfrey published an
article entitled "A Gummosis Associ-
ated with Wood Necrosis" (4), in which
he reported what was presumed to be a
new disease attacking citrus trees, prin-
cipally grapefruit, in the Rio Grande
Valley of Texas. This disease is con-

sidered by the Valley growers to be
their most serious citrus disease.
In November of 1949, in company
with Dr. Godfrey and his former assist-
ant Mr. Carl Waibel, I saw the Rio
Grande Gummosis disease on the Ex-
periment Station grounds at Weslaco.
Several days later symptoms of the
same disease were seen on grapefruit
trees in the Coachella Valley area of
California. Subsequently Mr. Waibel
informed the writer that he had assisted
Dr. Fawcett in identifying the disease


in California and that Dr. Fawcett was
satisfied that Rio Grande Gummosis is
distinct from the virus disease, psorosis.
This has an interesting bearing on the
early history of gummosis in Florida.
Upon returning to Florida, many
gummosis lesions were examined by the
writer and were found to resemble
closely the trouble seen in Texas and
California. Later Mr. Waibel visited
Florida and confirmed the suspicion
that Rio Grande Gummosis is none
other than the old Florida Gummosis
disease under a new name. Without
going into the complete history of this
disease, it should be noted that the
earliest detailed description of gum-
mosis in Florida was published by Faw-
cett in the Agricultural Experiment
Station Report of June 1907 (1). Later
he published other reports of his work
on gummosis, in one of which (2) he
explained how to distinguish gummosis
from foot-rot (Phytophthora citroph-
thora), and from leprosis (Florida
scaly bark disease). Recognition of the
importance of gummosis disease in
Florida reached its high point when
Rhoads and DeBusk published their bul-
letin in 1931 (5). After that date little
was published, and gummosis eventu-
ally came to be regarded as merely a
name to describe any disturbance giv-
ing rise to a little gum.
This situation is the result of a
peculiar set of circumstances and
events. In the first place some of the
symptoms of gummosis are remarkably
like certain symptoms of foot-rot on the
one hand and like certain symptoms of
psorosis on the other. As a result gum-
mosis has been confused with these dis-
eases. In addition gummosis has been
known under other names such as
"tears," and "gum disease," which led
to confusion. Uncertainty as the iden-
tity of the causal organism has been
detrimental to understanding gummosis.
When Fawcett reported (3) that he had

isolated Diplodia natalensis from gum-
mosis lesions and that Diplodia caused
more profuse gumming than any other
isolate many were led to infer that
Diplodia was the cause of the gumming
when neither foot-rot nor psorosis
seemed to fit the case. Although Faw-
cett reported that Diplodia inoculations
did not form typical gummosis lesions
(3), that fact was overlooked by many.
It seems as though it was overlooked by
Fawcett himself for when he later
recognized the disease in California he
did so under the name of Rio Grande
Gummosis. However Diplodia infec-
tions cause the wood to become dark
grey to black in color, which contrasts
sharply with the buff and orange color
typical of citrus wood infected with
gummosis. Also, Diplodia readily at-
tacks sour orange causing profuse gum-
ming, but Stevens (6), Rhoads (5), and
Godfrey (4) all agree that sour orange
is highly resistant to if not immune
from gummosis disease. As a result of
these facts there is basis for consider-
able doubt that Diplodia is more than
a secondary invader of gummosis

The symptoms of the gummosis dis-
ease as seen in Texas parallel closely
the symptoms in Florida and are in
close agreement with those described
by Fawcett in 1907. On that basis, the
disease as found in Florida, Texas, and
California can safely be regarded as a
single disease for which the name gum-
mosis, as originally used in Florida,
should take precedence.
Gummosis lesions may be active at
any time of the year and on lemon trees
they appear to be active almost con-
tinuously. On grapefruit the period of
greatest activity seems to be early
spring. This year (1949-1950). the dis-
ease was especially active from Decem-


ber through February, perhaps because
of an unusually warm winter and an
early spring. Since lemons ceased to
be grown commercially in Florida (due
in large part to gummosis, although
foot-rot is usually blamed), gummosis
is most frequently seen affecting ma-
ture grapefruit trees. Any point on
the trunk and larger limbs may be at-
tacked. The following table (Table 1)
adapted from Rhoads and DeBusk (5)
indicates the relative susceptibility of
several citrus species to gummosis.
Tie Susceptibility of Several Species of Citrus to
Gummosis as Indicated by the Presence and Extent
of Lesions. Adapted from Rhoads and DeBusk
Lemon Most susceptible
Grapefruit Very susceptible
Sweet Orange Moderately susceptible
Tangerine Very resistant
Sour Orange Most resistant

There are roughly speaking two types
of lesions, depending on age and man-
ner of infection. In appearance young
infections are very similar to young
infections of foot-rot, i.e., a small quan-
tity of light-colored gum oozing from a
small spot where the bark appears
slightly wet or water-soaked. However,
the cambial surface of the wood be-
neath the gumming spot lacks the
brownish-yellow stain characteristic of
foot-rot infections. Frequently (at
least on grapefruit trees) small woody
galls or outgrowths from the wood un-
der the bark are found associated with
young gummosis infections. These out-
growths are usually green in color due
to the presence of chlorophyll presum-
ably stimulated by the disease. So far
as is known such outgrowths are not
found associated with foot-rot, with
Diplodia infections, or with the virus
disease, psorosis. Usually there is no
bark scaling at the time of first gum
production, although the bark may split
slightly. Young lesions appear to heal

by sloughing off a thin scale of dead
outer bark, exposing a buff-colored scar.
This occurs shortly after gumming
ceases. The scar consists of callus tissue
generated by the bark. Healing is only
temporary, for later in the year, or per-
haps the following year, gum exudes
again, and additional scales of bark
slough off, thus enlarging the lesion and
repeating the cycle. In the course of re-
peated gumming and scaling, the lesions
enlarge to cover a considerable area, and
in time the wood becomes exposed. The
direction of greatest enlargement is
parallel to the axis of the trunk or limb
and not around the circumference, as is
the case with the psorosis. In addition,
psorosis lesions always look ulcerated
and give no appearance of healing, even
temporarily. In foot-rot lesions the
bark is killed down to the wood and is
subsequently sloughed off as a single
slab, and any healing that occurs takes
place at the margins of the lesion.
In older infections of gummosis the
disease usually has penetrated deep into
the wood, and as a result it is often
necessary to chisel through a half inch
or more of healthy wood to expose the
gummosis infection. When thus ex-
posed the cut surface of the infected
wood is seen to be a buff or buckskin
color usually banded and bordered with
a salmon-orange color that deepens in
shade when exposed to the air. The
banded appearance is due to the wood
of certain growth rings having become
impregnated with gum. Frequently
gum collects in lens-shaped pockets that
cause the outer layers of woodland the
bark to become raised as though by
large blisters. When these "gum pockets"
break through to the surface large
quantities of semi-liquid gum are re-
leased. The cavities vary in size, some
being half an inch thick by an inch
wide by two inches long, and the in-
ternal walls are usually covered with
small gall-like protuberances that some-


times enlarge to the point of filling the
cavity. The disease appears to pene-
trate long distances through the wood
so that gum pockets may be formed at a
considerable distance from the nearest
bark lesion. The importance of the
gum pockets in diagnosing gummosis
disease was noted by Fawcett in 1907.
A summary of the more characteristic
symptoms of gummosis is presented in
Table 2, in comparison with the symp-
toms of foot-rot and psorosis, the two
diseases with which it is most frequent-
ly confused.

Causal Organism
At present the cause of gummosis
must be considered as unknown since
there is no published record of typical
symptoms of gummosis having been
produced by inoculation with a pure
culture of any organism or with a
virus. The causative agents of foot-
rot, psorosis, and Diplodia infection
have been satisfactorily disposed of as
possible causes of gummosis, and many
years ago in Florida Fawcett (3)
showed that uninfected mechanical in-
juries to citrus trees did not gum. It
is true that certain chemicals stimulate
gum formation, but the remainder of
the symptom picture is lacking, i.e.,
cycles of gumming and healing, gum
pockets, and certain other features have
not been found associated with chemi-
cally induced gumming. The only other
causal agent worth consideration at this

time is the one reported from Texas.
Godfrey found what he describes as an
actinomycete-like fungus associated
with the disease. Up to the time I talked
with him in 1949 he had been unable to
obtain this organism in pure culture,
but he has been able to cause the dis-
ease on numerous occasions by inocula-
tions with chips of diseased wood. Al-
though this organism is suspected, its
causal relationship has not been proved.

From the citrus grower's point of
view, emphasis on the identity of the
causal organism is somewhat academic.
What he wants to know is how the dis-
ease spreads and how it can be stopped.
Old gummosis infections in Florida and
in Texas indicate that pruning wounds
are the most important point of entry
of gummosis, with other bark injuries
only slightly less important. In Texas
the disease is sometimes referred to as
"wet-back" disease because it is so
often associated with bark injuries
caused by Mexican fruit pickers, "wet-
backs," who frequently climb the trees
when picking fruit. Whether the or-
ganism can penetrate through unin-
jured bark is not known, though judging
from some of the young lesions seen in
Florida this year, it seems that it can.
However, young infections that take
place through the bark are easily cared
for, and do not present the same hazard
as infections arising in the wounds that


Disease Symptoms

Bark Sloughing
Gum Pockets in Wood
Color of Affected Wood

Causal Organism


Entire bark thickness
Yellow to Brown



Very heavy
Outer scales
Buff with
Salmon Bands


Practically none
Outer scales



result from cutting off large branches.
The practice has been to remove large
branches by sawing them off as close
to the trunk as was convenient and to
let the stump heal over as best it could.
Even under the most favorable circum-
stances, it takes several years for a
large pruning wound to heal over. In
the meantime, the wound is open to
infection by gummosis and other
All pruning wounds three-quarters of
an inch in diameter or larger should
have a wound disinfectant applied to
them. For this purpose few materials
are as satisfactory as Avenarius or Red
Arrow carbolineum. In addition, any
wound 11/ inches or larger should have
a coating of water-emulsified asphalt
applied to the carbolinelim dressing one
week afterwards. Such treatment will
maintain the wound surface in a dry,
fungus-repellant state until the bark
has healed over it.
Painting the surface of an old wound
will not eradicate gummosis from deep
in the wood. Old infections will have
to be excavated with a chisel or gouge.
All the discolored diseased wood should

be removed and, after several days of
drying, the surface should be treated
with carbolineum and asphalt emulsion
as in the treatment of new wounds.
When gummosis disease has been estab-
lished a long time the grower will have
to determine whether the tree is worth
the expense of treatment. Young
lesions are easily excavated and heal
over in a short time if proper dressings
are applied. However gummosis lesions
that have apparently healed over with-
out adequate treatment are still alive
and will break out with renewed activ-
ity at a later date. The proper treat-
ment of wounds is an excellent example
of the adage that an ounce of preven-
tion is worth a pound of cure.
1. FAWCETT, H. S. Gumming of Citrus. In Fla.
Agr. Exp. Sta. Ann. Rpt. (1907), p. xlvi-xivii.
2. .... ....,--- Gummosis. In Fla. Agr. Exp. Sta.
Ann. Rpt. (1910), p. xlix-li.
3 ..---.,------ Gumming. In Fla. Agr. Exp. Sta.
Ann. Rpt. (1912), p. lxxvii-xcii.
4. GODFREY, G. H. A Gummosis of Citrus Associ-
ated with Wood Necrosis. Science 102 (2640):
180, 1945.
5. RHOADS, A. S., and DEBUSK, E. F. Diseases of
Citrus in Florida. Fla. Agr. Exp. Sta. Bulletin
229 (1931), p. 66-74.
6. STEVENS, H E. EGummosis. Fla. Agr. Exp.
Sta. Ann. Rpt. (1914), p. Ivii-lxxiv.


Citrus Experiment Station
Lake Alfred

The investigation of spreading decline
of citrus in Florida has been in progress
for the past five years. During that
time information on the varieties of
citrus and the rootstocks on which the
decline was found has been reported (1).
In addition, the effect of the disease on
the tree (1) and the rate at which the
decline spreads in the grove have been
discussed (1,2). At one time it was con-
sidered that the citrus nematode (Tylen-
chidus semipenetrans Cobb) might be

associated with spreading decline (1)
but subsequent results showed that the
citrus nematode was not the causative
agent for typical spreading decline (2).
In the experimental work on virus trans-
mission, no evidence was found to indi-
cate that the disease was caused by a
virus (1,2). Although preliminary in-
vestigations did not indicate that a
fungus was responsible (1), it appears
that the trouble may be the result of a
fungus infection of the fibrous roots that
gradually spreads through the grove
from root to root (2). Numerous ex-
periments with various types of possible
control measures were conducted but no


successful method for the control of the
disease was found (1,2).
Considering all of the information al-
ready obtained and the additional results
accumulated since the last report in
1949, what is the present status regard-
ing spreading decline?
Spreading decline occurs on all vari-
eties of oranges, grapefruit and tan-
gerines budded on rough lemon, sour
orange, sweet orange or grapefruit root-
stock. The presence or absence of the
disease on other kinds of rootstocks has
not been determined. The number of
groves in which typical spreading decline
is present are located as follows: Polk
County-74, Orange County-8, High-
lands County-5, and Hillsborough Coun-
ty-2, making a total of 89 groves. There
are a number of groves in which spread-
ing decline occurs that we do not have
on our list.
Those trees which have spreading de-
cline show sparse foliage and reduced
growth but do not die. The trees with-
in the decline area all show the same
degree of decline and a distinct margin
is evident with the decline trees on one
side and the healthy trees on the other.
The disease gradually spreads from the
declining trees to the adjacent healthy

Rate of Spread
To determine the rate of spread of the
disease, the groves are mapped each
year after the spring flush of growth.
The yearly maps are then compared to
obtain the number of trees that become
diseased during any given year. Since
the decline spreads at the margin of
the diseased area, the rate of spread is
obtained by dividing the number of
trees that become diseased by the num-
ber of trees on the margin of the de-
cline area. The results obtained from
25 selected groves are presented in
Table 1. These data show that con-
siderable variation occurred in the rate

of spread in the various groves from
1945 to 1950. The marginal rate of
Yearly Variation in Rate of Increase of Spreading
Decline in 25 Groves.
Rate of Spread1
Grove 1945- 1946- 1947- 1948- 1949- Average
1946 1947 1948 1949 1950
1 1.6 1.1 0.3 2.5 out 1.4
2 1.2 1.4 0.6 2.8 1.0 1.4
3 1.0 0.8 0.7 0.9 2.7 1.2
4 1.1 1.4 2.3 2.3 1.8
5 0.2 1.7 1.8 2.7 1.3 1.5
6 0.7 1.5 0.9 1.5 1.6 1.2
7 1.0 2.0 1.0 3.0 0.5 1.5
8 0.3 0.8 0.7 1.3 out 0.8
9 0.5 1.1 1.3 2.8 0.8 1.3
10 0.6 0.6 1.6 3.8 2.3 1.8
11 1.1 0.7 2.0 1.5 1.3
12 2.3 0.7 2.0 out 1.7
13 1.9 1.9 2.2 0.6 1.7
14 1.1 4.7 0.5 2.1
15 1.1 5.2 1.5 2.6
16 2.0 3.0 1.8 2.3
17 1.8 1.1 0.5 1.1
18 0.9 2.7 0.5 1.4
19 3.2 8.3 5.7
20 4.1 0.9 2.5
21 2.6 1.0 1.8
22 2.7 0.6 1.7
23 1.5 1.0 1.3
24 1.6 0.6 1.1
25 4.3 0.1 2.2
Average 0.8 1.4 1.1 2.7 1.5 1.6

1 Increase in number of diseased trees per tree on the
margin of the declining area.
Increase in Number of Diseased Trees in Affected
Groves During a Five Year Period.
No. Diseased Trees
Grove 1945 1950 Increase
2 13 138 125
3 77 244 167
4 164 511 347
5 121 296 175
6 21 199 178
7 29 142 113
9 51 152 101
10 66 249 183

. . .. o


spread varied from 0.1 to 8.3 trees with
an average of 1.6 for all groves through-
out the five years. Six groves showed
an average rate of spread of over 2.0
for the five-year period. The greatest
average yearly spread was in 1948-49
when the rate was 2.7. In general,
spreading decline can be expected to
move outward 1 or 2 trees per year.
To demonstrate the total number of
trees that may become diseased over a
period of years, the data obtained from
8 groves was examined. These groves
had been mapped six times and complete
records for the five-year period were
available. As is shown in Table 2, the
number of diseased trees in the groves
varied from 13 to 164 when they were
mapped in 1945. By 1950, the number
of diseased trees varied from 138 to
511. Grove No. 4 showed the largest
increase but also had the most diseased
trees in 1945. However, the increase
in number of diseased trees was not
always greater in the groves that had
more diseased trees at the beginning of
the experiment as illustrated by com-
parison of the data from groves 5 and 6.
Apparently the conditions in some of the
groves were more favorable for the de-
velopment of spreading decline.

Causal Agent
Spreading decline appears to be the
result of a disorder of the fibrous roots
of the tree. No evidence has been found
to indicate that the disease is caused by
a virus. Although the citrus nematode
is present in a number of groves in Flor-
ida, it was not found in groves which
have typical spreading decline. Two
kinds of fungi can be consistently isolated
from the fibrous roots of the diseased
trees. One is a Fusarium sp. and the
other has not yet been identified. It is
probable that the spreading decline is
caused by a fungus infection of the
fibrous roots. A number of experiments
are in progress to determine whether

either of these two fungi may be the
causal agent.
One characteristic of a Fusarium dis-
ease is the ability of the fungus to pro-
duce a toxic wilt-inducing material when
grown in Richard's solution. This toxic
material adversely affects the host when
the disease occurs under natural condi-
tions. In the case of spreading decline,
a toxic material was obtained from water
extracts of the fibrous roots, the woody
portion of larger roots and the leaves
from diseased trees. This toxic material
caused the wilting of citrus cuttings
within 48 hours and of tomato cuttings
in 24 hours. Extracts from healthy
trees did not cause a wilting of the
cuttings. Fusarium cultures No. 16,
29 and 35 obtained from diseased trees
were grown in Richard's solution for
two weeks and the filtrate tested for
wilt inducing ability. The filtrate from
culture 29 was more toxic than that
from the other two cultures in causing
a wilt of citrus cuttings. Since.a wilt
inducing material can be extracted from
the diseased trees and is produced by
the growth of the fungus in Richard's
solution, it is indirect evidence that the
spreading decline may be the result of
the infection of the fibrous roots by a
Experiments have been conducted
and are in progress to determine the
effect of soil from a spreading decline
area, healthy grove soil and virgin soil
on the growth of rough lemon seedlings
and young Duncan grapefruit trees on
rough lemon rootstock. In one series
of tests, the seedlings in the decline
soil show a reduction in growth com-
pared to that of the seedlings in the
other soils. It has also been found that
Tendergreen beans and sunflowers de-
velop a greater amount of root rot when
grown in soil from a spreading decline
area than occurs when they are grown
in soil from the healthy part of the
grove. Both of the previously men-


tioned fungi have been isolated from
the diseased bean and sunflower plants.
In one instance, velvet beans were used
as a cover crop in the spreading decline
area of a grove. The stand was poor
and about 50 percent of the plants
showed root rot. A number of other
kinds of plants will be tested for their
susceptibility to root rot when grown in
soil from a spreading decline area. If
a satisfactory test plant can be found,
it will be possible to evaluate the effec-
tiveness of the various soil treatments
more rapidly than can be done by grow-
ing citrus seedlings.
Control Measures
Considering the evidence obtained, it
is doubtful if a treatment can be found
which will rejuvenate those trees that
have spreading decline. Therefore, to
control spreading decline, two problems
should be considered. How can we stop
the spread of the decline in a grove?
What soil treatment should be used
before the area is replanted? In some
cases, growers have attempted to con-
trol spreading decline by removing
those trees which were visibly diseased.
Within a few months those trees at the
margin, which appeared healthy when
the other trees were removed, began to
show typical decline symptoms.
Before decline can be properly con-
trolled it will be necessary to know the
number of trees affected with the dis-
order which are located in advance of
those trees showing visible symptoms.
Since plant pathogens often affect plant
metabolism a measurement of the rate
of respiration of citrus leaves or roots
should show whether differences exist
in:metabolic activity between appar-
ently healthy trees in advance of the
decline margin. A difference in meta-
bolic activity might be indicative of the
spread of the pathogen.
The rate of respiration of fibrous
roots from healthy trees and decline

trees was measured using 40 root tips
from each tree. The root tips were
suspended in a 2 percent glucose solu-
tion and placed in a Warburg respirom-
eter at 330 C. where oxygen measure-
ments were made at 10 minute intervals
for a period of one hour. The rate of
oxygen absorption by the roots secured
from three typical groves is shown in
Table 3. It was evident in every meas-
urement that the rate of respiration of
the decline trees was lower than the
respiration rate of the healthy trees in
the same grove. The data also indicate
that in the majority of the groves tested
there was a successive increase in
respiration rate from the decline area
up to and including the third healthy
tree beyond the decline margin. In
every grove the respiration rate was
highest for the third or fourth healthy
tree beyond the decline margin. The
rate of respiration of healthy trees be-
yond the fourth tree was slightly lower
than the third tree but usually higher
than the first or second healthy tree.
It was also interesting to note that the
respiration rate was practically the
same for all healthy trees in the same
grove located more than 4 trees beyond
the visible margin of spreading decline.
Although these data are preliminary in
nature it would appear that the decline
Respiration Rate of Fibrous Roots from Decline Trees
and from Consecutive Healthy Trees in
Advance of the Margin.
Condition .Microliters of Oxygen per Hour
Tree No. of Tree Grove 1 Grove 2 Grove 3
0 Decline 15.3 23.4 22.5
1 Healthy 18.6 26.6 30.3
2 Healthy 22.5
3 Healthy 34.3 38.4 41.2
4 Healthy 33.1
5 Healthy 31.2 31.8 30.6
6 Healthy 29.2
7 Healthy 28.8 33.8 30.8
8 Healthy 28.8
9 Healthy 31.3 29.1 29.0


casual factor had an initial stimulating
effect on the respiration rate of the
third or fourth healthy tree. It would
seem logical, therefore, that as the
invasion became more severe the
respiration rate was reduced as illus-
trated by the lower metabolic activity
of the first and second healthy tree.
Respiration studies are being con-
tinued and additional indices evaluated
as an aid in the interpretation of the
significance of metabolism in the third
and fourth healthy trees beyond the
decline area.
The activity of the catalase enzyme
in the leaves has been used occasionally
as an indication of the rate of metabolic
activity. Sixty leaf discs were selected
from each tree and ground while fresh
with a mechanical mortar. Catalase
was determined in Heinicke tubes
rotated in a constant temperature water
bath. The amount of catalase was ex-
pressed as the cubic centimeters of
oxygen generated in 90 seconds when
the sample was mixed with hydrogen
peroxide. The catalase activity of the
leaves secured from one grove is shown
in Table 4 although the same general
relation held for other groves that were
tested. In general, there were greater
variations in catalase measurements of
the leaves than were apparent in the
respiration rate of the roots. These
differences may have been due to the
greater experimental error in the
catalase procedure. However, it is
significant that in every grove tested
the third or fourth healthy tree beyond
the decline margin had the most
catalase present.
Since a preliminary study of the
physiology of the citrus tree has in-
dicated some variation up to the fourth
visibly healthy tree ahead of the margin
of the decline area, it is probable that,
if all of the diseased trees plus four or
five good trees around the area were
removed, the disease could be elimi-

nated. Assuming that this procedure
would be effective, what would be the
result if this had been done in 1945 in
the eight groves which we have
studied? As is shown in Table 5, the
number of diseased trees in every grove
is greater now (1950) than the number
The Catalase Activity of Grapefruit Leaves from
Consecutive Trees Across the Margin
of the Decline Area.

Tree No.

of Tree

Catalase as cc. of 0,,
Released in 90 Sec.

Hypothetical Loss of Trees by Pulling to Prevent
Spread Compared to Actual Loss by Unchecked
Spread of Decline.
Trees in 1945 Trees in 1950
Grove Decline Pulled Total Decline
2 13 99 112 138
3 77 97 174 244
4 164 174 338 511
5 121 133 254 296
6 21 105 126 199
7 29 68 97 142
9 51 82 133 152
10 66 88 154 249

of decline trees plus a margin of four
trees that would have been removed in
1945. Arrangements have been made
to try this procedure in three groves
this winter. It will be two or three
years before definite conclusions as to
its effectiveness can be obtained.
It is possible that a chemical barrier


maintained in a grove might stop the
spread of the decline. Such a barrier
would need to kill the roots to eliminate
root contact and have some disinfecting
action on the soil. Preliminary tests
with cyanamid, formaldehyde and D-D
(dichlorapropane-dichloropropene) indi-
cated that a formaldehyde solution
should be effective as a barrier. The
barrier would be examined periodically
and when the roots started to grow
back into the treated soil, the chemical
would be applied again. A system of
barriers at different distances ahead of
the margin has been established in nine
groves. Formaldehyde at 3 gallons to
100 gallons of water was injected into
the soil at the rate of 2 gallons of solu-
tion per 5 feet of barrier. It is possible
that some results will be obtained by
If either or both of the above men-
tioned measures of pulling marginal
trees or using a chemical barrier will
stop the spread of the decline, then the
problem remains as to a satisfactory
treatment for the soil so that replants
will grow properly. In February, 1948,
two blocks of spreading decline trees
were removed and the soil treated with
D-D at 400 pounds per acre. The treated
areas were replanted with budded trees
and records on growth are being ob-
tained. After two years, the trees
planted in the treated soil are making
better growth than those in the non-
treated soil. The data from one of the
blocks are shown in Table 6. The D-D
is not a good fungicide, but at the rate
used has some fungicidal effect.
In another experiment rough lemon
seedlings were planted in decline and
virgin soils which had been treated
with D-D, formaldehyde and ethylene
dibromide in December 1948. In Octo-
ber 1950, 6 out of 18 seedlings in the
non-treated decline soil had died and
the remaining plants had grown about
two-thirds as much as the seedlings in

the treated decline soil or in the non-
treated or treated virgin soil. Final
records have not been made but there
does not appear to be any significant
difference in the growth of the seed-
lings whether in treated decline soil,
or in the non-treated or treated virgin
Treated Soil Non-Treated Soil
Caliper 1.91 in. 1.75 in.
Height 5.80 ft. 4.93 ft.
Spread 5.69 ft. 5.18 ft.

To obtain additional information on
various materials that might be effec-
tive as a soil treatment, a series of tests
were started in May 1950. A total of
56 materials are in the test. It may be
possible to obtain some information by
the spring of 1951.
Groves in which spreading decline is
present in Florida are located in Polk,
Orange, Highlands and Hillsborough
counties. Over a five year period, the
average rate of spread of the decline in
all groves mapped was 1.6 trees per
tree on the margin of the decline area.
During the same period, the number of
trees with the disease increased from
2 to 9 times in different groves.
Spreading decline appears to be the
result of a fungus infection of the
fibrous roots. A Fusarium sp. and an
unidentified fungus have been consis-
tently isolated from the roots of dis-
eased trees. Indirect evidence obtained
by means of the "wilt test" has indi-
cated that a Fusarium may be the
casual agent.
Tests on the respiration and catalase
activity of rootlets and leaves of dis-
eased and healthy citrus trees indicated
that the disease may extend to the third
or fourth healthy tree ahead of the


margin of the decline area. Any at-
tempt at controlling spreading decline
by removal of the trees should also in-
clude at least four healthy trees ahead
of the margin.
Rough lemon seedlings have made
better growth when the decline soil was
treated prior to planting with D-D,
formaldehyde or ethylene dibromide in

pot experiments. Field tests with D-D
at 400 pounds per acre appear promis-
1. Surr, R. F. Spreading decline of citrus in Flor-
ida. Proc. Florida State Ilort. Soc. 60: 17-23,
2. SUIT, R. F. and L. C. KNOHR. Progress report
on citrus decline. Proc. Florida State Hlort. Soc.
62: 45-49, 1949.


Citrus Experiment Station
Lake Alfred
During the past two years purple mite
Paratetranychus citri McG. infestations
have been general throughout the whole
citrus area, and they have persisted
even during the summer months. As a
rule, purple mites are difficult to find
in August and September but during
these months in 1949 and 1950, light to
medium infestations were observed in
many groves. Purple mite populations
were at a higher level during the sum-
mer of 1950 than during any other sum-
mer period on record.
Although no particular cause has
been determined for the unusually
heavy and widespread infestations,
favorable weather conditions for mites
have existed. Purple mites are often
more numerous during and following
periods of dry weather and it may be
significant that in 1950 the rainfall at
Lake Alfred was below normal each
month from January to August inclu-
Spray and cultural practices are
factors of considerable importance in
the development of purple mite infesta-
tions. Thompson (2) reported in 1938
that purple mites increased following
copper sprays, and in 1942 Holloway
(1) stated that the citrus red mite (pur-

pie mite) in California was more nu-
merous following sprays containing
compounds of copper, zinc and lime
than where no sprays were applied. In
1944 Thompson (3) also reported that
purple mites were more numerous fol-
lowing sprays containing lime-sulfur
or compounds of copper or zinc, than
where no sprays of any kind had been
applied. In fact, the infestations were
as heavy where lime-sulfur had been
applied as a dormant spray as where
either zinc or copper was used in the
spray mixture.
Copper residues on the foliage bear a
relationship to purple mite infestations
as shown by the data in Table 1. The
purple mite infestations were heavier
in November where a neutral copper-
oil emulsion combination was applied
in April than where a neutral copper-
wettable sulfur was applied at the same
time. Analyses (5) of the copper resi-
dues* on the leaves showed that there
was significantly more copper on the
leaves where the copper-oil combina-
tion was applied and a higher mite
population resulted. It should be em-
phasized here that the figures in the
table represent only external copper.
In the opinion of the authors, it is this
external copper residue which influ-
ences purple mite infestations.

Made by C. R. Stearns, Associate Chemist, Citrus
Experiment Station.



Copper Spray
'lots Combinations
Applied May 6
23 Copper-W. Sulfur'

Dates of
Oil Sprays

20 Copper-Oil2

Copper-W. Sulfur

19 Copper-Oil
30 Copper-W. Sulfur
21 Copper-Oil

Copper-W. Sulfur

June 3

June 16

July 14

July 14

Aug. 4

22 Copper-Oil Aug. 4
Neutral copper (34W9 metallic Cu) @ 3-100 + w
SProprietary copper-oil emulsion @i 2 gallons-100.
3 Copper analyses made by C. R. Stearns, Jr.

Parathion has been used as an insec-
ticide for the control of scale insects
and mealybugs during 1949 and 1950
and some growers are of the opinion
that it is a factor in increases of purple
mites. Following the summer sprays
for scale control it was found that pur-
ple mites were more numerous after an
application of parathion than after an
oil spray. Parathion killed the active
mites, but it did not kill the eggs nor
did the residue on the leaves and fruit
remain toxic long enough to kill the
young mites as they hatched. By com-
parison, an oil emulsion spray killed the
active mites as well as the eggs. Thus,
if there is an infestation of purple mites
in the grove when an application of
parathion is made, it may be expected
that mites will again be present within
a week or two after the application.
The parathion situation may be fur-
ther complicated by the use of almost
all other sprays or dusts. In the sum-

Copper Deposit"

Percent Leaves

on Foliage Infested with
mcg/cm2 Av. Purple Mites Av.
1.6 10
1.9 1.8 6 8.0
3.7 67
3.0 3.4 51 59.0
1.7 23
2.7 2.2 27 25
3.7 73
4.3 4.0 55 64
2.5 2
1.2 1.8 10 6.0
3.3 64
4.1 3.7 63 63.5
2 1
1.8 1.9 1 1
5 11
4.7 4.8 11 11

ettable sulfur 12%-100.

mer of 1950, observations at seven loca-
tions in Polk County demonstrated some
of the interactions to be expected when
different spray programs are used. The
data are presented in Table 2.
From these data and other data not
shown here, it would seem that the use
of copper, zinc and sulfur are major
factors influencing summer and fall
purple mite infestations and that para-
thion is a minor factor. The average
purple mite infestations were highest
in plots where copper, zinc, lime and
wettable sulfur had been applied as a
post-bloom spray and followed with
sulfur in the summer. Where nothing
but sulfur sprays or sulfur dusts were
used throughout the season the mite
populations were higher than where
parathion was used and much higher
than in the unsprayed trees. The light-
est infestations were in the plots
sprayed with oil emulsions and in the
untreated plots. However, it should be



Post-Bloom Application

Percent Infested Leaves
Summer 1 2 3 4 5 6 7
Application Aug. Aug. July July Sept. July July Averages
23 15 26 26 16 2 13

Copper, zinc, lime, sulfur Oil emulsion 2 6 2 0 2. 2.4
Copper, zinc, lime, sulfur Parathion' 36 24 26 32 10 25.6
Copper, zinc, lime, sulfur Sulfur 53 23 66 90 58.0
sulfur Parathion' 24 24.0
sulfur Sulfur 39 46 37 28 37.5
No sprays or dusts 16 5 2 10 0 2 1 5.0
Wettable sulfur 10-100 was combined with parathion.

noted that during the spring, all plots,
including the untreated ones, were
heavily infested.
Although spray residues may affect
purple mite infestations, the type of
weather still appears to be the domi-
nant factor in influencing widespread
mite populations. Lime-sulfur, wet-
table sulfur, sulfur dust and compounds
of copper and zinc have been used over
wide areas in the state for many years
and generally heavy infestations have
been the exception rather than the rule.
If purple mites continue to be a prob-
lem during the spring and summer
months it will be desirable to have a
miticide that can be used safely during
periods when succulent foliage is pres-
ent .and during warm weather. This
problem will be intensified by the sub-
stitution of other scalicides for oil
emulsion. During the past two years
several new insecticides have been
tested for the control of purple mites
and they, along with the DN com-
pounds, are discussed in the following
DN Dry Mix which contains 40%
dinitro-o-cyclohexyl phenol, is still one
of the most satisfactory miticides on
the market but it is not safe to use
when there is succulent foliage present
or when the weather is hot.

DN-111, a preparation containing
20% dinitro-o-cyclohexyl phenol, /dicy-
clohexylamine salt applied at 11/
pounds per 100 gallons is as effective as
DN Dry Mix at 2/3 of a pound. It can
be combined with the same type of
spray materials that are used with DN
Dry Mix and is not so toxic to young
foliage as DN Dry Mix. DN-111 is
slightly more expensive than DN Dry
Mix per 100 gallons of dilute spray but
'it is within the economic range for
grove use.
In 1947, Thompson (4) reported that
Neotran, which contains 40% bis-
(p-chlorophenoxy)-methane, was effec-
tive in killing purple mites. Repeated
tests have been made with this material
and it has been found to be effective at
11/2 to 2 pounds per 100 gallons of
spray. It appears to be compatible with
all of the materials, including lime-
sulfur, now used as sprays on citrus in
Florida. It is one of the few miticides
on the market at the present time that
is effective when mixed with highly
alkaline solutions. No foliage injury
has been observed with this material
when it was applied in the spring on
succulent foliage or during the summer
months. The limiting factor of Neotran
is the cost, which at the present time is
approximately 80 cents per pound. Thus,
at two pounds per 100 gallons the cost


of 100 gallons of dilute spray would be
$1.60 or $8.00 per for a 500 gallon tank.
Another promising material, desig-
nated here as K-6451, is a wettable pow-
der containing 50 percent chlorophenyl,
p-chlorobenzene sulfonate. This ma-
terial does not result in a high initial
kill, but 7 to 10 days after the applica-
tion, very satisfactory control has re-
sulted. The period of control with this
material was somewhat longer than that
obtained with DN Dry Mix. However,
the period of control with K-6451 was
not as long during the warm spring and
summer months as it was during the
cool months from November to Febru-
ary. The minimum concentration for
good control has not been determined
but it will probably be 1 to 2 pounds
per 100 gallons. It appears to be similar
to DN in its compatibility with spray
materials. To date no injury has been
observed where it was applied to succu-
lent foliage or when it was applied dur-
ing the summer months. Taste tests of
the fruit as well as further experi-
mental work on compatibility and con-
trol will be needed before this material
is released for the public use. At the
present time there has been no informa-
tion released on the probable cost of
this material.
Aramite, a 15 percent mixture of
beta-chloroethyl-beta-(p-tertiary butyl
phenoxy)-alpha-methyl ethyl sulfite, has
shown some promise as a safe miticide
to use during the spring and summer
months. On an average this material
has not been as effective as DN, Neo-
tran or K-6451. Aramite, like all other
materials tested, was not as effective
during the summer months as it was
during cooler weather. It was found
to be compatible with most materials
used as sprays on citrus, but it was not
tested with highly alkaline materials.
No injury has been observed on succu-
lent foliage where this material was
used nor has there been any injury fol-

lowing sprays applied during June, July
or August. The present cost of Aramite
is also comparatively high.
Other materials tested in a limited
number of experiments included a 50
percent mixture of p-chlorophenyl
phenyl sulfone and EPN, a material
containing 27 percent of ethyl para,
nitrophenol, thionobenzenephosphonate.
Both of these materials appeared safe
to use on succulent foliage and during
warm weather but further tests are
necessary to determine their effective-
ness as a miticide.
It is interesting to note that where
the sprays were applied in April or May
the period of control was not so long as
where the same materials were applied
in November. It is quite possible that
one of the factors which shortened the
period of control was reinfestation of
mites from adjacent properties. The
plots sprayed in April and May were
adjacent to blocks that were heavily
infested with mites and there were indi-
cations in some experiments that adult
mites migrated into these plots within
5 to 6 days after the applications. In
one experiment no living mites were
observed 3 days after a thorough appli-
cation of an effective miticide. In com-
parison, the untreated plots were 100
percent infested. Four days later an-
other examination was made and an
average of 9 percent of leaves on the
sprayed trees were infested with adult
mites. It would thus appear that mi-
gration of adult mites took place be-
cause mites cannot develop from the
egg to the adult stage within four days.
In two other experiments conducted
during the spring months it was found
that adult mites made their appearance
5 to 6 days following an effective miti-
cide where no mites were found 3 days
after the application.
In Table 3 are recorded some of the
results obtained with the most promis-
ing materials tested. It is desirable



Materials and Concentrations in Pounds Figures Express Percent Infested Leaves
per 100 Gallons Pre- Nov. Dec. Dec. Jan. Feb.
Spray 12 1 80 19 10
Sprayed November 7
DN Dry mix .66 lbs. 92 0.2 0.0 0.0 1.4 9.5
K-6451 1.50 94 4.1 0.0 0.1 0.0 6.5
Neotran 1.50 94 0.0 0.0 0.4 2.1 21.5
Aramite 1.50 77 0.0 1.2 4.8 12.2 81.5
Nov. Nov. Dec. Jan. Feb.
Sprayed November 11 1 28 22 7 10
DN Dry mix .66 lbs. 15 0.0 0.8 3.8 33.5
K-6451 1.50 18 0.0 1.2 10.2 19.4
Neotran 1.50 14 0.0 0.0 2.9 32.1
Aramite 1.50 15 3.0 1.1 8.3 50.3
Jan. Jan. Feb. Feb.
Sprayed January 11 5 16 4 28
DN Dry mix .66 Ibs. 32 0.0 6.2 5.0
K-6451 1.50 42 13.0 1.9 1.5
Neotran 1.50 34 0.0 13.8 22.5
Aramite 1.50 48 0.6 19.0 10.5
No treatment 36 28.1 40.0 26.0
March April April April May May
Sprayed April 3 30 7 18 27 5 28
DN Dry mix .66 lbs. 33 1.7 1.0 0.0 19.1 60.0
K-6451 2.00 21 2.5 0.0 0.0 .4 2.5
Neotran 2.00 47 0.0 0.0 0.0 4.1 29.0
Aramite 2.00 4 6.0 1.0 1.2 27.1 61.0
No treatment 5 5.0 15.0 15.0 30.0 57.0
April April May May May
Sprayed April 17 13 21 2 8 23
K-6451 1.5 lbs. 10 0.0 2.0 18.0 45.0
K-6451 2.0 12 0.0 0.0 0.0 53.0
No treatment 33 45.0 77.0 88.0 97.0

to do: further experimental work with
all: of these new miticides, not only to
test their effectiveness, but also to test
their safety on foliage and fruit.

Timing and Application of Sprays
The period of control of purple mites
does not depend entirely on the miticide
used. One of the cardinal prerequisites
to obtaining a long period of control is
to apply the miticide before a high per-

centage of the leaves become infested.
This is illustrated in the following dis-
Although it is now well known that
parathion is not an outstanding materi-
al for the control of purple mites,
light infestations in four plots were
kept at a low level for two months
where parathion was included in a
dormant spray at 1 pound of 15%
material per 100 gallons of mixture.


When the application was made about
2 percent of the leaves were infested,
whereas two months later an average
of 8 percent of the leaves were infested
in the parathion plots as compared to
32 percent infested leaves where para-
thion was omitted. The parathion had
killed the few active mites, and since
there were very few eggs present at that
time, the mite population did not build
up in those plots until May.
The intensity of the infestation at the
time of spraying influenced the degree
of infestations at a later date. Thus,
in experiments where duplicate plots
were used, and where there was a dif-
ference of 20 to 30 percent in the
original infestation at the time of spray-
ing that difference was still apparent
at the conclusion of the experiment
although the level of population had
been substantially reduced by all treat-
ments. This was true in 88 percent of
the duplicate plots. For instance, on
January 3, Plot A had 18 percent of the
leaves infested and the duplicate, Plot
B, had a 43 percent infestation. Three
months after the application, Plot A
had 4 percent of the leaves infested
compared to a 35 percent infestation in
Plot B. This comparison is made to
stress the importance of treating groves
in October or November when the mite
population is at a low level, and treat-
ing again in January or February.
Mite populations will thus remain .at a
low level through the late winter and
spring months when grove conditions

are likely to be unfavorable for spray-
ing because of dry weather and the
presence of succulent foliage.
If dusting is practiced it is especially
important to make the application be-
fore the mite population reaches a high
level. If a high percentage of the leaves
are infested when a dust is applied, a
second application should be made
within a week or ten days to bring the
numbers down to a point where a rea-
sonable period of control can be
Thorough coverage is of prime im-
portance. None of the miticides are
considered fumigants and direct con-
tact is necessary for satisfactory con-
trol. The type of coverage that is
usually made for rust mite control is
not thorough enough for purple mite
control. Special care should be taken
to cover the tops of the trees where the
heaviest infestations are usually found.
HOnACE V. McBuroNiE. Population increases of
citrus red mite associated with the use of sprays
containing inert granular residues. Jour. Econ.
Ent. 35 (3): 348-350. 1942.
2. TOrMPsON, W. L. Cultural practices and their
influence upon citrus pests. Jour. Econ. Ent.
32 (6): 782-789. 1939.
3. THOMPSON, W. L. Progress report on purple
mite and its control. Proc. Fla. State Hort. Soc.
57: 98-110. 1944.
New insecticides and their application on citrus.
Proc. Fla. State Hort. Soc. 60: 86-90. 1947.
5. THOMeSON, W. L. Combined control of scale
insects and mites on citrus. Fla. Agri. Exp. Sta.
Ann. Rept. 71-73. 1948.



Bureau of Entomology and Plant
Washington, D. C.

As everyone knows, injurious insects
and plant diseases constitute serious
obstacles to agricultural production.
This seems to be true the World over.
Fortunately or unfortunately the de-
structive organisms that cause greatest
losses in one part of the World may not
occur in others. This feature of their
distribution gave rise many years ago
to efforts in various parts of the World
to set up restrictions aimed at protect-
ing the agricultural industry of one
country from plant pests known or be-
lieved to occur in another. These re-
strictions which we call quarantines
were in effect in some parts of the
World long before the United States
first gave consideration to its need for
similar plant-pest protection. By 1912
when this country first enacted legisla-
tion for this purpose many injurious
insects and plant diseases had found
their way here and had become estab-
lished. As fruit and vegetable produc-
tion is particularly vulnerable to attack
by these organisms, many States were
united in urging upon Congress the
need for action. The State of Florida,
because of its tremendous production of
these articles, was and continues to be
one of the leaders in urging the need
of some means of screening the arrival
here of additional plant pests. Florida
is particularly vulnerable because of
climate, crop specialization, geographi-
cal location, and proximity of serious
insect pests and plant diseases within
easy reach of Florida ports by air and
In 1912 Congress passed the Plant

Quarantine Act authorizing the Secre-
tary of Agriculture to promulgate rules
and regulations to safeguard the im-
portation into this country of nursery
stock, fruit, and other plant products.
It has been the policy of the Depart-
ment to take such action on a biological
basis. Care has been taken to avoid the
use of this authority in furtherance of
economic or competitive conditions.
Quarantines that have been promul-
gated have been aimed at specific sub-
jects and have been accompanied by
minimum restrictions consistent with
the objective of protection from insect
pests or plant diseases not known to
occur or to be widely distributed within
this country. The restrictions issued
under this legislation by the Secretary
of Agriculture have varied during the
years, depending to some extent on the
nature of the material which formed
the large percentage of the imports,
upon information with respect to pest
risks, and upon the advisability of the
application of methods of treatment to
safeguard the importations.
Much of the information on which
plant quarantines have been put into
effect through this authority by the
Secretary of Agriculture has been ac-
cumulated by the Bureau of Entomology
and Plant Quarantine. In the case of
plant diseases the basic information has
frequently been furnished by the Bu-
reau of Plant Industry, Soils, and Agri-
cultural Engineering. In the case of
every foreign plant quarantine the ob-
jective has been to get the most accu-
rate knowledge possible with respect to
the distribution of the insect or disease,
ways in which it might be transported,
materials on which it would be most
likely to be carried, the possibility of
destroying the organism through the


application of treatments at destina-
tion or port of entry, and the probable
damage likely to occur in this country
in the event of its introduction. In
general the policy on which quarantines
have been established has been to con-
sider the biological necessity to exclude
a specific plant pest and then to provide
such restrictions on the importationof
the plants or parts thereof which serve
as the host as will most adequately pro-
tect domestic agriculture.
With the passage of the Plant Quar-
antine Act the responsibility for deal-
ing with foreign quarantine problems
was placed on the Federal Government.
Plants and other restricted commodi-
ties imported into this country are con-
sidered to be in foreign commerce until
actually arrived at the point of destina-
tion. It has been held by legal advisers
of the Department that the States do
not have authority over such commerce
until delivery to the ultimate consignee.
At that point under the State police
powers the State plant quarantine offi-
cials have authority to make inspections
and take appropriate action.
As a result of research, much of
which has been done by the Bureau of
Entomology and Plant Quarantine,
means have been developed to destroy
injurious insects on various types of
commodities through the use of com-
modity treatments. These methods of
treatment are required as a condition
of entry for many different kinds of
plants and plant products. Tempera-
tures, both hot and cold, for specified
periods of time, poison gases, and vari-
ous insecticidal dips may be required.
These methods of treatment may be
prescribed in some cases after inspec-
tion as a precaution and in some cases
are required as definite conditions of
entry. In the case of fruits originating
in countries where fruit flies of various
species are known to occur, the time-
temperature treatments are required as

a condition of entry. There are 3 gen-
eral procedures under which these
treatments may be applied: (1) At port
of entry under the supervision of rep-
resentatives of the Bureau; (2) in the
country of origin and at the present
time this is applicable only to Mexico
where arrangements have been made
whereby representatives of the Bureau
may do such work at the expense of the
exporters, and (3) the application of
the treatment in transit. It has been
found that the temperature and the
exposure duration are not the same for
all species. More extreme temperatures
and longer time intervals are needed
for some. These commodity treatments
are effective when properly applied and
with experience it has been possible to
simplify and standardize equipment and
procedures to make their application
more effective and less costly.
One of the serious problems is our
inability to recognize the symptoms of,
or to control, that class of diseases
which is caused by the presence of a
virus. In the inspection of nursery
stock entering the United States it has
been found impossible through inspec-
tion at the ports of entry to be sure as
to the presence or absence of a number
of virus diseases. It was primarily be-
cause of the need to strengthen our pro-
tection against virus diseases accom-
panying imported nursery stock that
led to the revision of Quarantine 37,
the Nursery Stock, Plant, and Seed
Quarantine, a few years ago providing
the requirement of growing the material
for a specified period of time in post-
entry detention to permit inspection
during one or more growing seasons.
It is recognized that postentry pro-
cedures leave something to be desired.
It is not the best procedure to bring
plants into this country, establish them
in our soil, and then await the possibility
that they may have brought some seri-
ous infestation or plant disease. It is


believed, however, that inspection dur-
ing the growing season offers the best
chance to detect the presence of virus
diseases in plants. It is hoped that it
may be possible to arrange that our
inspectors may examine the material
in the country of origin. Inspection of
the growing material in the nurseries
abroad and the rejection there of ma-
terial which appears to threaten our
welfare would seem to be more practi-
cable and effective. If the means and
the trained men were available to in-
augurate such a program it would be
necessary that there be an invitation
from the countries involved to make the
inspections within their borders. Some
progress has been made in this direc-
tion. Inspectors of the Bureau have
visited a few countries on specific
errands involving the inspection and
application of treatments for the safe-
guarding of materials destined to be
shipped to this country. It is believed
the recognition of the advantages of
this method of procedure will grow and
it is hoped that by this means a satis-
factory substitute for the present sys-
tem of postentry inspection may be
A step in the direction of more effec-
tive international cooperation was taken
when the United States was represented
at the recent International Conference
on Plant Quarantine Regulations con-
vened by the Netherlands Ministry of
Agriculture at The Hague. This initial
conference resulted in a draft of an
international agreement which is now
before the countries concerned for con-
sideration. Its provisions include:
Statements of Purpose and Responsi-
bility; Supplementary Agreements
under the Convention; Establishment
of National Organization for Plant Pro-
tection; Requirements in Relation to
Exports; Requirements in -Relation to
Imports; International Cooperation;
Amendment of Convention; Settlement

of Disputes; Treatment of Non-adher-
ing Countries; Ratification and Ad-
herence, and Effective Date. From par-
ticipation in this Convention it is be-
lieved the United States should benefit.
The question has been asked whether
this would mean that the Federal in-
spectors would have to accept certifi-
cates from officials of other countries.
The answer to this is no. We do not
have to accept their certificates now
and the proposed standardization would
not modify this authority. To my
knowledge no agency of the Federal
Government has sought to influence
decisions of the Department of Agri-
culture based on biologically sound re-
quirements for imported plant material.
From the standpoint of this country
it is believed international discussions
such as this International Agreement
contemplates may afford us a chance to
establish relations with other countries
which it is hoped may lead to the op-
portunity for our inspectors to work
with their inspectors in the nurseries
from which shipments are made to the
United States. It is our hope that this
would furnish some first-hand infor-
mation about the conditions surround-
ing the material which is offered for
entry into this country.
In recent years plant pests have been
transported over long distances as
never before through the movement of
airplanes. Planes taking off in one part
of the World and landing in another
all between sunrise and sunset means
that living insects may be transported
and become established as has not been
the case with slower transportation.
Florida has occasion to fully under-
stand the consequences in terms of
dangers of plant pest distribution due
to the enormous increase which has
taken place in international air trans-
portation. The burden of inspection
which has fallen on the Florida State
Plant Board in Florida and on the


Bureau of Entomology and Plant Quar-
antine throughout the country is in
direct proportion to the expansion in
this activity. In the first 9 months
of 1950, 14,500 planes from foreign
ports were inspected in the State of
Florida by State and Federal inspectors
There are numerous instances of the
long-distance transportation of living
insects by means of airplanes. Evidence
is abundant that some injurious
species have been established in distant
parts of the World through this means.
It seems reasonable to believe that the
danger of the long-distance dissemina-
tion of injurious insects through air
travel is likely to increase unless
definite measures are taken to prevent.
With this objective experiments are be-
ing conducted to develop insecticides
to be applied to interiors of airplanes.
Planes from Hawaii are sprayed be-
fore departure from the Mainland, care-
ful inspection is being made of foreign
planes on arrival at the airports in this
country, and representations have been
made to the agricultural officials of
other countries looking toward their
adoption of precautions which might be
of protection to them as well as to us.
Florida is interested in the status of
the diseases of citrus known as mal
secco, quick decline and tristeza, and of
the infestations of the citrus blackfly
in Mexico and the oriental fruit fly in
In Mexico work against the citrus
blackfly has been carried on in coopera-
tion with the Mexican Department of
Agriculture and with committees of
growers organized in some of the prin-
cipal fruit-growing States of that coun-
try which have actively participated in
the suppressive program. Infestation
was found early in 1950 as close to the
border as Matamoros just across the
Rio Grande from Brownsville. This
was a light infestation found on one

tree on a property within a few doors
from the bus station which leads to the
belief that the insect may have reached
that point in connection with bus travel
from interior points of Mexico. That
infestation is believed to have been
eradicated and no recurrence has been
found to date despite frequent and care-
ful inspections. Bus travel is inter-
rupted at the border as the vehicles
themselves do not cross. The question
whether the insect may be carried as a
hitch-hiker on traffic crossing the line,
however, is under investigation. This
involves the possibility of spraying
such vehicles in connection with their
crossing and search is being made for
a suitable spray.
Infestation now occurs in the City of
Monterrey where spraying is being car-
ried on at all points where living citrus
blackflies are known to occur. Other
infested areas in Mexico where sup-
pressive measures are being applied
include Victoria and one or two points
between Victoria and Monterrey; also
in the vicinity of Valles in the State of
San Luis Potosi about 300 air miles
south of the border where rather heavy
infestations of the citrus blackfly have
occurred over a period of several years.
At that point a Bureau spray program
is in progress on selected properties to
demonstrate that fruit production can
be restored if proper sprays are applied
at the right time.
On the West Coast the infestations
which were found in the vicinity of
Guaymas and Empalme have been sub-
jected to several spray applications. In
this area it will be recalled the first
suppressive measures were put into
effect by the fruit growers of Arizona
and California who contributed funds
and sent their own men to supervise the
program. In this initial effort the
Bureau cooperated by determining the
limits of infestation to the northward
in cooperation with the Mexican Depart-


ment of Agriculture. The number of
infested properties has been steadily
reduced as well as the intensity of the
In Cuba the citrus blackfly was found
to be readily controlled by parasites.
These same insects taken to Mexico
and liberated there have not proven to
be equally effective. It will be recalled
that there was an infestation of the
citrus blackfly in south Florida on Key
West a number of years ago. Resort
was not made to natural control at that
time as it was deemed desirable to com-
pletely eradicate the infestation if pos-
sible and after a spray program of some
duration in which the Bureau coop-
erated with the State Plant Commis-
sioner, it is believed the infestation was
completely wiped out. Parasites were
imported into Mexico during the season
1948-49 from Malaya. There was diffi-
culty in making these introductions be-
cause the infestations were on citrus in
that country. Because of the danger
of bringing citrus canker infested
material to Mexico the procedure was
to take potted citrus trees from Mexico
to Malaya, there infest them with the
citrus blackfly, then introduce the para-
sites, cage the infested plants and ship
by water. Little success attended these
efforts, perhaps because of the long
period of time involved. In the season
of 1949-50, parasites were collected in
India. In this instance it was possible
to secure infested non-citrus leaves
carrying the parasites. These were
shipped at frequent intervals by air
and a large amount of the material
came through successfully. Sufficient
time has not yet elapsed to permit an
evaluation of the effectiveness of these
beneficial insects. It would very great-
ly lessen the concern of the fruit grow-
ers of this country if biological control
of the citrus blackfly in Mexico should
prove to be effective.
With respect to the oriental fruit fly

situation in the Hawaiian Islands, a
very comprehensive research program
was undertaken in the beginning of the
fiscal year 1950 with funds made avail-
able by the first session of the 81st
Congress. The work was divided into
five main projects:
(1) Biology and habits of the fruit
(2) Treatment of agricultural prod-
ucts grown in infested areas so
that they may be transported
safely into uninfested areas
(3) Search for insecticides that will
kill the insect
(4) Large-scale control and eradica-
tion studies
(5) Biological control
The work in these lines of investiga-
tion has been vigorously prosecuted.
The importations of beneficial insects
have been very encouraging. A num-
ber of the imported species have been
recovered from various parts of the
Islands showing that they have become
definitely established and at some
points the parasitization has reached
an encouraging level. Active coopera-
tion in the studies directed against the
oriental fruit fly is being received from
California and from Hawaii. The Cali-
fornia State Department of Agriculture
and the Citrus Experiment Station of
the University of California have been
actively cooperating. They have loaned
men to this undertaking and accepted
responsibility for certain activities
associated with the general program.
The Board of Agriculture and Forestry
of Hawaii and the Hawaiian Experi-
ment Station are also valued coopera-
tors. The Pineapple Research Institute
and the Hawaiian Sugar Planters Asso-
ciation Experiment Station are also giv-
ing valuable assistance.
Airplanes leaving Hawaii for the
Mainland are given preflight inspection
and are also sprayed in an effort to


prevent hitch-hiking fruit flies. Care-
ful inspection and treatment of prod-
ucts moving to the Mainland are re-
quired. California has been carrying
on a trapping program in order that if
the fly should find its way there the
infestation would be discovered while
still in the incipient stage. The results
of this trapping program have thus far
been negative in California.
Plant quarantine policies and pro-
cedures have been undergoing rather
frequent and rapid changes. Progress
in the development of insecticides, ad-
ditional information as to the distribu-
tion and abundance of plant pests, and
the possibility of long-distance dissemi-
nation all have contributed to this situ-
ation. In this country the State plant
quarantine officials, by working to-
gether, have made notable progress in
simplifying, coordinating, and stream-

lining the State quarantines and pro-
cedures which affect interstate ship-
ments of plants and plant products.
Their organizations-the regional and
the National Plant Boards have
afforded a medium for free friendly
discussion of their mutual problems.
It is believed that progress in dealing
with other countries is possible through
similar means. Long strides in this di-
rection have been made in our dealings
with our neighbors, Canada and Mexico.
Working at greater distance there has
been excellent ground work laid for
further cooperative relationships with
Argentina, Australia, and Holland.
Better understandings lead to better
cooperation. From our point of view
better cooperation means fewer plant
pests accompanying agricultural im-
ports and that is the aim which must
be kept ever before us.


Florida Citrus Experiment Station
Lake Alfred

During the past few years, spray
machines have been developed for ap-
plying concentrated sprays to deciduous
fruit trees. The purpose of such
sprays was to apply the required
amount of the active ingredient to the
tree with a minimum amount of water.
By reducing the actual gallons of spray
per tree the cost of application may be
decreased both by eliminating the haul-
ing of water and by reducing the time
required to refill the spray tank. If the
spray mixture is concentrated four
times the ordinary strength, then there
is a saving of 75% in the amount of
water hauled, and a similar amount of

time saved in filling the tanks. With
concentrated sprays such a low volume
of fluid is delivered per tree that no
run-off or dripping occurs. The pur-
pose of this paper is to present results
on the use of concentrated sprays on
citrus in Florida.*
The first concentrate type sprayers to
be used on citrus in Florida were tested
by King and Griffiths (2) in 1947. Two
machines (Buffalo Turbine and Hessian
Microsol Generator) were tested in the
control of the American grasshopper in
citrus groves. These machines gave
very poor insecticide distribution on the
tree. In spite of this, relatively satis-
factory grasshopper control was ob-
tained. However, it was concluded that

*For those readers who desire information concerning
the history and theory of concentrated sprays reference
is suggested to a thesis by R, M. Pratt (6).


this type of machine would not be
practical for the control of sedentary
citrus pests.
At the start of the 1949 spray season,
a Hardie mist sprayer** was loaned to
the Citrus Experiment Station. This
machine is powered by a 45 h.p. gasoline
engine. Air is delivered to only one
side at the rate of approximately 20,000
cubic feet of air per minute and at a
velocity of 110 miles per hour. The
pump capacity is 18 gallons per minute,
and the pressure is maintained at ap-
proximately 400 pounds. The principles
involved in the design of this machine
were developed at Cornell University
(4,5,6). The basic design is such that
the air is driven up into the tree, and
the desired spray particle size is pro-
duced by the use of high pressures.
Also in 1949, the Speed Sprayer Com-
pany began developmental work on modi-
fied nozzles to be used in a Speed
Sprayer (Model 36) for the delivery of
concentrated sprays. In contrast with
the Hardie sprayer, a Speed Sprayer
delivers approximately 44,000 cubic
feet of air to two sides or 36,000 to one
side, and the velocity varies between
90 and 105 miles per hour. It is pow-
ered by a 110 h.p. gasoline engine. A
centrifugal pump is employed to deliver
spray solution at a pump capacity of
150 gallons per minute at 65 pounds
A number of other concentrate spray-
ers are being offered for sale in other
parts of the United States. One of
these, the Lawrence Mist-o-Matic
Sprayer, was tried in the summer of
1950. The distribution of spray mate-
rials appeared to be satisfactory in the
tops and on the off-sides of the trees,
but the lower 6 feet of the tree adjacent
to the sprayer were not covered. This
machine will require considerable modi-

**Mist sprayer as defined by Pratt (6) is a sprayer to
be used for the application of concentrated sprays.

fiction in order to make this a practical
sprayer for use in citrus groves.
During 1950, some caretakers have
successfully applied double concentra-
tions of toxicants at half gallonage
with the conventional nozzles in a Speed
Sprayer. Such semi-concentrates rep-
resent a compromise between dilute and
concentrated sprays, but they represent
a trend in the direction of concentrated
The work reported here deals with
experiments conducted during the 1949
and 1950 seasons using the Hardie
sprayer and the Speed Sprayer. In most
cases, the spray was applied at one-
eighth the gallonage and at six times
the concentration normally used. This
meant that three-fourths as much mate-
rial was being applied per tree as with
a dilute spray. Previous work on
apples had indicated that less material
was necessary when no drip occurred

Mite Control.-During the 1949 and
1950 seasons the two concentrate spray
machines were compared with a dilute
Speed Sprayer in an orange grove near
Auburndale. The dormant spray (zinc,
DN, sulfur), the post-bloom spray (cop-
per and sulfur), and summer and fall
sulfur sprays were applied with this
machinery. The summer spray for scale
control was an oil emulsion applied by a
hand machine. Careful checks were
made of purple mites and' rust mites
throughout the two years. There was
no significant difference in the control of
these pests that could be attributed to
the use of concentrate sprays. In similar
small scale tests, rust mite and purple
mite control was as satisfactory with
concentrated as with dilute sprays.
Scale Control.-Three rather extensive
scale control experiments have been per-
formed. In 1949, a parathion experi-
ment was carried out in a grove near


Auburndale. Parathion was used as a
concentrated material and compared with
both a 1.3 percent oil spray and a dilute
parathion spray, both of which were ap-
plied by hand as well as by Speed Spray-
er. Duplicate plots were used in all
The concentrated material was ap-
plied with the same nozzle settings in all
plots, but the machines were driven at
three speeds, which resulted in more
gallons being applied per tree at the
slower speeds. The concentration of in-
secticide was so regulated that the com-
parable amounts of parathion were ap-
plied per tree. Half of the plots sprayed
with concentrate had the parathion con-
centration arranged so that only three-
fourths of the standard quantity was
used per tree. The results of this experi-
ment are shown in Table 1. In one of
the Hardie plots, purple scale control was
unsatisfactory, apparently due to nozzle
stoppage and to the fact that distribu-
tion of the insecticide was poor. It was
concluded from this experiment that
there was no significant difference in

control caused by the use of dilute as
compared to concentrate sprays, by the
use of the Hardie Mist Sprayer versus
Speed Sprayer, or by the use of 25 per-
cent less parathion as compared to the
usual amount of parathion.
Another scale control experiment was
performed at Lake Placid in 1949. This
compared dilute sprays in a Speed
Sprayer with concentrated sprays in
both the Hardie Mist Sprayer and the
Speed Sprayer. The standard applica-
tion was supposed to consist of 28 gal-
lons per tree of a 1.3 percent oil spray.
All sprays were applied at the rate of 1
mile per hour. Three nozzle sizes were
used in both the Speed Sprayer and the
Hardie Sprayer. This was done in
order to vary the amount of water
applied per tree. The concentration
of oil used in the Speed Sprayer was
arranged so as to deliver the same
amount of oil per tree as would be
applied if a 1 percent oil were used at
28 gallons per tree. For the Hardie
Sprayer, three oil concentrations were
used which were equivalent to the oil

Speed Gal./
Mi./Hr. Tree
1.0 5.0
1.0 5.2
Speed Sprayer 1.5 3.5
Concentrate 1.5 3.3
2.0 2.3
2.0 2.3

Lbs. Para-

JUNE 30, 1949.
% Mortality
Avg. of Two Plots

1.0 3.0 .031 93
1.0 3.6 .054 80
1.5 2.7 .042 98
Hardie Sprayer 1.5 2.9 .068 97
2.0 2.5 .052 100
2.0 2.5 .078 97
Speed Sprayer 1.0 25.0 .062 99
Dilute 1.0 25.0 1.3% oil 100
Pressure Sprayer ...... 18.0 .041 99
Dilute .... 17.0 1.3% oil 99


that would have been applied in the
1.3, 1.0 and a 0.8 percent oil emulsion,
all used at 28 gallons per tree. The
results are shown in Table 2. The gal-
lons of spray per tree, the actual pints
of oil per tree, and the oil deposit on
the foliage is shown. There were sig-
nificant correlations between the
amount of oil sprayed per tree and the
amount deposited per unit leaf area.
Both of these factors were, in turn,
significantly correlated with purple
scale control. Red scale control was
generally more satisfactory than purple
scale control, and as a result, the
former did not show correlation be-
tween the rates of application and the

percent control It was concluded that
the amount of oil deposited evenly over
a tree was the important factor, and it
appeared that it did not make any dif-
ference what strength or gallonage was
applied so long as sufficient oil was
spread uniformly over the leaf and twig
Leaf drop was not severe following
this spray. However, where the con-
centrate sprayer turned around the tree
at the end of a row, the terminal tree
had severe leaf drop. This suggested
the fact that with oil sprays at least, the
sprayer should come out of the grove,
drive past the end tree, and then cut off
the spray before turning around. This



Hardie Mist


Gal. of

Pts. Oil/

% Mortality
Oil Deposit Purple Red
Mcg./Cm' Scale Scale
57 60 80
36 37 87
36 70 97
46 72 97
43 73 100
60 86 91
59 65 96
43 77 96

Speed Sprayer

1.5 1.3
1.0 1.0


1.5 1.0 10.3 3.1 38 79 90
1.0 7.0 3.1 50 93 100
1.0 4.5 3.3 88 90 100
1.0 1.3 23.0 2.3 28 77 90


would avoid excessive oil deposits and
subsequent leaf drop on the end tree.
In 1950, oil emulsion and parathion
sprays were compared in a grove near
Auburndale. These materials were ap-
plied by hand with pressure rigs, as
dilute sprays in the Speed Sprayer, and
as concentrated sprays in both the Hardie
Mist Sprayer and the Speed Sprayer.
The results of this experiment are shown
in Table 3. The basic spray was consid-
ered to be 25 gallons per tree of a 1.3
percent oil or parathion at 2 pounds of
15 percent wettable material per 100 gal-
lons of spray. The concentrated sprays
were designed to apply equal amounts
of insecticide in one set of plots and
only three-fourths as much in another
set. Because of irregular delivery by
both machines, no conclusions could be
made regarding the rate of dosage.
Purple scale control was satisfactory in
all applications regardless of the method
of application. There was more leaf
drop following oil than parathion and
more with concentrated than dilute oil,

but in no instance was the leaf drop
Fruit Grade in Packinghouse.-In
1949, representative samples of fruit
from the experimental plots at Auburn-
dale were checked in the packinghouse
in order to compare grade as well as
insect and mite injury on fruit. In this
comparison, there was no difference
either in grade or external quality which
could be attributed to a difference in the
methods of application. In other words,
concentrated sprays appeared to have
produced as satisfactory or as good
quality fruit as that produced by dilute
spray machinery.

During 1949 and 1950 sufficient work
with concentrated sprays has been per-
formed to demonstrate that they will
probably be practical for use on citrus
in Florida. Lime-sulfur, wettable sulfur,
DN, zinc sulfate and lime, neutral copper,
oil, and parathion have all been applied
successfully. However, before concen-

Gal % Reduction Leaf Lbs. % Reduction Leaf
Machine Oof Parathion/ of
Oil/Tree Purple Scale Drop Tree Purple Scale op

.20 80 64 .059 80 5
Hardie Sprayer .23 92 56 .052 100 32
.29 75 78 .056 97 16
.36 77 118 .080 100 32
.29 91 52 .060 100 22
Hand Sprayer .34 92 40 .081 99 59
Speed Sprayer .33 96 39 .066 97 19
Dilute .29 82 56 .066 93 43
.24 91 63 .067 96 29
.31 84 33 .080 93 35
Speed Sprayer .25 89 94 .060 95 39
Concentrate .33 82 33 .057 97 34
.42 95 67 .072 95 22
.31 90 93 .072 87 33

o Based on total newly dropped leaves on 1/5 of the area under the tree on July 81.


trate sprays can be generally used, a
number of problems must be studied
and solved. The grower will no longer
be able to think in terms of how many
pounds of material to use per 100 gal-
lons of spray. Rather he will have to
know how much copper is needed on a
given size tree to control melanose, how
much zinc sulfate is needed on a given
size tree to maintain optimum zinc
levels, and how much parathion per
tree is needed for scale control. As an
example, it may take two-thirds of a
pound of 15 percent parathion on a
large grapefruit tree to control scales,
and it may take only one and one-half
pounds of sulfur to control the rust
mites. In this case, parathion and
sulfur will be used in a ratio of 4
pounds of 15% parathion to 9 pounds
of sulfur. If three gallons are to be
applied per tree, then 33 trees will be
sprayed with 99 gallons and each 100
gallons of spray will contain approxi-
mately 22 pounds of 15 percent para-
thion and 50 pounds of sulfur. This
example shows that considerable calcu-
lation may be necessary in order to
figure out the proper amounts of ma-
terial to use per tank of spray.
The gallonage to apply per tree poses
another difficulty. In experimental
work, one-eighth the normal gallonage
has been used in most cases. It may be
determined subsequently that still
greater concentrations will be satis-
factory, but, in any case, the gallons to
be applied per tree will determine the
amount of material per 100 gallons of
spray. If the grower plans to apply
3 gallons and actually applies 31/2 gal-
lons per tree, he will not only use an
extra half gallon per tree, but also this
will represent a 17 percent increase in
material costs. With dilute sprays, a
half gallon error resulted in less than
a 5 percent increase in material costs.
With concentrated sprays, small errors
in gallons delivered per tree will result

in big differences in the amount of
material applied per tree.
In the case of the Hardie Sprayer,
gallonage is regulated by the aperature
size in the spray disc and not by the
number of nozzles. Thus, the rate of
delivery into the top or the bottom of a
tree is also regulated by disc size. It
will take considerable knowledge on the
part of the operator to properly set the
nozzle sizes and adjust the air flow
baffles for proper distribution over the
tree as well as for the proper gallonage
per tree. Tall trees need larger nozzle
sizes at the top and small trees need
more spray concentration at the bottom.
In the case of the Speed Sprayer, gal-
lonage can be regulated either by nozzle
aperature size or by the number of
nozzles. Since the number of nozzles
will probably be less than one-fourth
the number now used with dilute sprays,
distribution will again be a problem, as
it will be difficult to determine which
pipe is to hold 1 and which 2 or 3 noz-
None of these problems are insur-
mountable. Most can be solved by time
and thought, but before attempting to
use concentrated sprays a grower
should be acquainted with the difficul-
ties involved, and he should have suffi-
cient information to be able to ade-
quately determine the amount of materi-
al to use and the gallons per tree to
The use of concentrated sprays on
citrus can result in savings to the grow-
er. Probably less insecticide will be
needed per tree. Table 4 presents sulfur
deposits for one experiment where the
Hardie Mist Sprayer was compared with
a Speed Sprayer delivering dilute
sprays. The deposits are calculated on
the basis of micrograms of sulfur de-
posited on a square centimeter of leaf
surface per pound of sulfur applied to
the tree. Thus, they are a measure of
the amount of sulfur which stuck to the



Hardie Mist Sprayer
Concentrated Spray
On Side Off Side
35 42
33 49
25 26
34 46

Speed Sprayer
Dilute Spray
Top On Side Off Side Top
19 19 19 8
25 19 21 14
15 32 36 10
25 32 44 9
21 25 30 10

leaf surface. The figures are for the
sides of the tree adjacent to the sprayer
(on side), the side between the trees
(off side), and the tops. The concen-
trated spray deposited 25 to 50 percent
more sulfur than did the dilute spray.
This is similar to information from
other sources (1,3). In the case of oil
emulsion sprays this may not be true,
but in all other instances there are
definite indications that the amount of
material can be reduced over that
which is normally sufficient to dilute
In addition to material savings, there
should also be operational savings. It
will no longer be necessary to use one
or possibly two supply units for an in-
dividual sprayer. Whereas a 500 gallon
tank of dilute spray will spray possibly
only 25 trees, 200 trees can be sprayed
with a tank of concentrate. Therefore,
one supply unit should be able to supply
2 or even 3 sprayers in a single grove.
This represents a saving in spray labor
as well as in the use of the machinery.

Summary and Conclusions
Concentrated sprays have been used
experimentally during the 1949 and
1950 spray season on citrus in Florida.
Two machines, the Hardie Mist Sprayer

and the Speed Sprayer, appear to offer
good possibilities for use with this type
of spray. In general, one-eighth the
normal gallonage was used per tree.
and indications were that with the pos-
sible exception of oil, less spray materi-
al could be used per tree than with
dilute sprays. In comparative trials,
the control of rust mites, purple mites,
scale insects, and melanose have been
as satisfactory with concentrated
sprays as with dilute sprays. It was
concluded that the use of this type of
spray should be practical on citrus in

1. BURRELL, A. B. 1950. Concluding remarks on
concentrate spraying. Proc. N. Y. St. Hort. Soc.
2. KING, JOHN R. and J. T. GRIFFITHS. 1948.
Results of the use of concentrated sprays in
citrus groves in Florida. Fla. Ent. 31:29-34.
3. PARKER, K. G. 1950. Further studies on mist
spraying. Proc. N. Y. St. Hort. Soc. 95:105-108.
4. PARKER, K. G., R. M. PRATT, and L. R. BROWN.
1948. Spray duster for fruit trees. Farm. Res.
5. PRATT, R. M. 1947. The development of the
new Cornell experimental spray-duster. N. Y.
State Hort. Soc. Proc. 92:182-140.
6. PRATT, R. M. 1950. Investigations of fungicide
deposits and fruit tree disease control by the
spray-dust and mist spray methods as compared
with conventional hydraulic spraying. Thesis on
file Cornell University Library, Ithaca, N. Y.






Florida Citrus Experiment Station
Lake Alfred

For many years potash has been a
major constituent in the fertilizer mix-
tures applied to citrus in Florida. The
use of potash in modern amounts has
seemed reasonable, for citrus soils in
Florida are not well supplied with po-
tassium containing minerals. There is
consequently, only a minimum supply
of potassium for utilization by growing
citrus trees in Florida except as fur-
nished in the form of fertilizer. Like
nitrogen, potassium does not accumu-
late in these sandy soils (15) and much
of that not absorbed by the roots of the
trees is lost. Unlike nitrogen however,
potassium deficiency symptoms are not
quickly discernable under field condi-
tions. A number of papers have been
published covering one phase or another
of the work on the use of potash on
grapefruit at the Citrus Experiment
Station and at this time it seems de-
sirable to summarize these findings up
to date. In this paper the symptoms
which have been found to be associated
with potassium deficiency in the field,
and the effect of variable potash fertili-
zation on the internal and external
quality and on production of Duncan
grapefruit are presented and related
papers reviewed.

Literature Review
A study of the literature dealing with
potassium nutrition of citrus reveals
that a large number of symptoms have
been associated with potassium defi-
ciency. It should be kept in mind that

in most cases these symptoms have been
observed where citrus was growing
under artificial conditions in pot or sand
culture, and that to-date, many of these
symptoms have not been observed under
field conditions. The reported symp-
toms include dying-back of the upper-
most branches of the tree with the lower
branches showing little signs of defi-
ciency (2); splitting and gumming of
the twigs; scorching and excessive drop
of leaves, resinous spotting, fading of
the chlorophyll, and development of a
bronze-yellow color (Haas 11-12-13-14).
Tucking, and twisting of the leaf blades
is still another symptom, (4). With the
exception of results reported by Bryan
(2), the deficiency symptoms referred
to were associated with orange varieties
and not grapefruit. Whether all of
these symptoms apply to grapefruit has
not yet been established.
Fruit symptoms associated with
potassium deficiency have also been
fairly well classified, although there are
some controversial reports as to the
effect on the external appearance of the
fruit. Bryan (2) reported that in the
few cases where fruits were produced
on trees grown in pot culture, under
deficiency conditions, the fruit did not
appear to differ from fruit produced by
trees which received potassium in suffi-
cient amounts. Eckstine et. al. (8) have
described fruit produced under potassium
deficiency as being thick-skinned, coarse,
and with poor color. Fruit of small size
has been reported by most workers to be
characteristic of fruit produced by
potassium deficient trees, (1, 6, 13, 14,
19). It is generally agreed that oranges
produced by trees deficient in potassium
will contain a lower percentage of citric


acid in the juice, (17, 1, 19, 13, 14). Roy
(17) has further reported that Valencia
oranges not supplied with potassium pro-
duced fruit with a higher content of re-
ducing sugar, a lower content of non-re-
ducing sugar, and a lower pH of the
Although it was believed for many
years that muriate of potash was an in-
ferior source of potassium for the fer-
tilization of citrus, investigations by
Roy (17), Cowart (7) and Bahrt and
Roy (1) have shown that either potas-
sium sulfate or chloride are satisfactory
fertilizer salts. An explanation of the
background concerning these sources of
potassium is necessary for it emphasizes
the importance of magnesium in relation
to potash fertilization practices, and to
some extent the effect of magnesium on
the interpretation given to some of the
earlier potassium experiments. During
World War I, this country was forced to
depend largely on domestic sources of
potassium. One of these, potassium
chloride caused trouble because of the
boron which it contained. Because of
these experiences, combined with un-
satisfactory results from using muriate
on other crops, especially tobacco and
potatoes, potassium chloride was held in
disfavor and preference was given to
sulfate as a source of potassium for
Kainite also used as a source of potas-
sium contained appreciable amounts of
magnesium as magnesium sulfate and
chloride. As magnesium deficiency be-
came more wide-spread in Florida in the
late twenties and early thirties it was
found that larger applications of Kainite
improved the quality of fruit on these
magnesium deficient groves. Large,
coarse fruit is associated with mag-
nesium deficiency and when Kainite was
applied to deficient trees the fruit quality
improved not because of the potassium
but because of the added magnesium.

The potash source experiment started
in 1924 at the Citrus Experiment Station
and continued until 1942, furnishes an-
other good example of the effect of mag-
nesium on the interpretation of results
of a potassium experiment. This experi-
ment was initiated to ascertain the effect
of muriate, sulfate and sulfate of potash
and magnesia on the growth and produc-
tion of citrus. After several years the
sulfate of potash and magnesia appeared
to be a superior source of potassium.
When under the direction of Dr. A. F.
Camp, magnesium sulfate was added to
the muriate and sulfate of potash treat-
ments in amounts equivalent to the mag-
nesium contained in the sulfate of potash
and magnesia treatments, the differences
between the plots disappeared (7).
These examples illustrate the multi-
plicity of factors which are frequently
involved in studying fertilizers for tree
crops, some of which may not even have
been considered when the experiment was

The experiment discussed in this
paper was first started in 1921, as re-
ported by Ruprecht (18). At that time
a block of Duncan grapefruit was laid
out into six plots in such a manner that
plots designated as 1, 3 and 5 received
3 percent, and plots 2, 4 and 6 received
10 percent potash in the fertilizer mix-
ture. In the 1924 report, Ruprecht
stated that the potash treatments for
plot 5 were changed so that 3 percent
potash was applied in the spring, 5 per-
cent in the summer and 10 percent in
the fall applications. During the period
between 1924 and 1929 the plots were
changed again so that plot 5 received
5 percent potash at each application
and plot 6 received 3 percent potash in
the spring, 5 percent in the summer and
10 percent in the fall applications. The
plots were continued in this manner


until 1936, at which time the original
experiment was discontinued and the
plots were turned over to Dr. A. F.
Camp and his co-workers at the Citrus
Experiment Station.
In the 1930 report, Ruprecht (18) had
stated that the trees in the plots re-
ceiving 10 percent potash were in an
unsatisfactory condition. It later de-
veloped that the cause of this condition
was due to deficiencies of magnesium,
copper, zinc, and manganese, with mag-
nesium deficiency being especially
acute. In order to correct this condi-
tion nutritional sprays were applied,
and 4000 pounds of dolomitic limestone
was applied to part of this block during
1936, 1938 and 1939, with the same
potash treatments as used by Ruprecht
being continued.
Beginning with the fall application
in 1939, plot 6 was changed to a 0 per-
cent potash treatment and the trees in
this plot have received no potash fer-
tilizer since that time. During the
period since 1936 the trees have been
on a 3 percent nitrogen program, and
since 1939 have received a mixture with
the formulas shown in Table 1. These
mixtures are applied three times a year
in February, June and October. The
poundage has varied somewhat through
the years, having been increased as the
trees became larger. Since 1939 the
poundage has varied between 15 and 20
pounds per application. Zinc is ap-
plied annually as zinc sulfate at the
rate of 3 pounds per 100 gals. as a

dormant spray. Except as noted, the
plots all receive identical treatment in
keeping with good grove management
The term internal fruit quality as
used in this paper refers to internal
characteristics of the fruit based on
soluble solids, citric acid, and ascorbic
acid content of the juice. Total soluble
solids were measured with a Brix hydro-
meter and the readings corrected to a
temperature of 17.50C. Total titratable
acidity, (calculated as anhydrous citric
acid) was determined by the titration of
a 25 ml. aliquot juice against .3125 N
sodium hydroxide solution. The ascorbic
acid (vitamin C) content was deter-
mined by the method of Menaker and
Guerrant (16) and reported as milli-
grams of ascorbic acid per 100 millili-
ters of juice.

Visual Deficiency Symptoms under
Field Conditions-Under artificial con-
ditions, it is possible to grow citrus trees
which manifest deficiency symptoms of
potassium rather rapidly. This is not
true under field conditions because it is
not possible to eliminate potassium from
a soil as can be done with a nutrient solu-
tion. The increased period of time re-
quired for deficiency symptoms to be-
come evident in the field is due to several
factors. The tree stores potassium, which
apparently may be redistributed and re-
assimilated to such an extent, that the
growth centers are not immediately
affected. Also, a citrus tree appears to

Plot No. Formula (Percentage)
Plot No.
N PO2, K,O MgO MnO CuO
6 3 6 0 3 1 1/2
1&3 3 6 3 3 1 1
5 3 6 5 3 1 1
2&4 3 6 10 3 1 1/2


be relatively efficient in absorbing and
utilizing potassium ions with which its
root system comes into contact, (20).
Still another factor is the reutilization
of potassium resulting from the decompo-
sition of dropped fruit in the grove.
Where potash fertilization was withheld
entirely from the trees in plot 6, begin-
ning in 1939, no symptoms of potash de-
ficiency developed until the spring of
1943. Following the cold period of
February 15-18, 1943, it was observed
that the trees in this plot suffered more
cold damage than in the plots where
potassium was supplied. It was also be-
coming evident at this time, that the
trees were showing less top growth and
that the leaves were smaller, but very
marked differences in tree appearance
were still not evident. At about the same
time, it was noted that more fruit was
dropping previous to harvest where
potash was withheld. This condition
continued to develop and by the 1945-46
season was very evident. The trees not
supplied with potash have thus far con-
tinued to bloom and set fruit, but begin-
ning sometime in July a heavy pre-har-
vest drop occurs which usually continues
through the harvesting season. Table 2,
shows the percentage of the crop which
dropped during the past two seasons. The
larger number of drops listed for the
1949-50 season includes fruit which was
blown from the trees during the August
27th hurricane. During the past three
seasons the drops have been removed
regularly from the grove and since start-
ing this practice the trees appear to be
declining more rapidly from potassium
deficiency than before, indicating the
potassium reserve in these trees is be-
coming low. It should be noted that had
the experiment been discontinued before
the spring of 1943, say at the end of 3
years, a flat but erroneous conclusion
could have been drawn that potash fer-
tilization was unnecessary,

Another potassium deficiency symptom
which has been apparent on occasions is
the tendency for the trees not supplied
with potash to lose young shoots during
windy periods. During the early part of
March, 1950, rather high winds with
light rains occurred for several days
shortly after the spring flush of growth
The Effect of Variable Potash Fertilization on the
Pre-harvest Drop of Duncan Grapefruit.
Percentage of Dropped
Fertilizer Fruit*
Treatment 1948-49 1949-50
3- 6 0 3 1 / 45.7 82.5
3- 6 3- 1 I 37.3 67.2
3- 6 -5 3 1 % 29.5 68.5
3- 6 -10 3 1 1/ 29.5 62.9
*Values represent percentage of total number of
fruits. Drop counts were made from September 23
through Dec. 3, 1948, and from August 31 through
Nov. 25, 1949.

had appeared. About a week later it was
observed that a number of young shoots
3 to 15 inches in length had been blown
from the trees and were lying on the
ground. The number of shoots blown
off in each of the potash plots is re-
corded in Table 3. The break always
occurred at the point of emergence of the
shoot from the stem or branch.
At the present time there are no dis-
tinct observable differences in tree con-
dition between the trees which are re-
ceiving the 3, 5 and 10 percent potash
applications, but there is a sharp contrast
between the potash fertilized trees and
those which receive no potash fertilizer.
Trees in the latter plot are decreasing
in size, the tops are thin and the leaf
size now appears small on a number of
trees. Leaf symptoms denoting potas-
sium deficiency are not obvious. Some
twisting and tucking of the leaves of a
few trees have been noted on occasion.
Internal Fruit Quality. Sampling and
analyses of the fruit produced by the
trees in the potash plots has been con-


tinued regularly since 1939. A consid-
erable amount of data relative to fruit
quality has been obtained, but only data
for the past three years covering soluble
solids, percent citric acid, solids/acid
ratio and the vitamin C content is being
presented at this time. This is representa-
tive of the data as a group and shows the
difference in these juice characteristics as
influenced by the potash treatments
which the trees have received.
Contrary to results reported by Roy
(17) and Bahrt and Roy (1) in their
study of Valencia oranges, the soluble
solids content of the juice of Duncan
grapefruit from potassium deficient trees
is significantly lower in most cases than
where potassium is supplied. Variations
in the rate of potash application between
3 and 10 percent in most cases caused no
significant difference in the soluble solids
content of the juice (Table 4). The per-
centage of titratable acid is consistently
and very sharply reduced where potash
is limiting, and is increased significantly
with increasing applications of potash
up to 10 percent in the fertilizer mixture
(Table 4).

Loss of New Shoots as Affected by Variable Potash

3- 6 3- 1 1/
3- 6 3 3 1 'A
3- 6 -5 3 1 V%
3- 6-10 3 1 '

Average Number of
Shoots Lost Per Tree


In as much as the ratio, (soluble
solids/acid) of grapefruit juice is usual-
ly the factor determining earliness of
maturity for grapefruit, the effect of
potash applications on the ratio is of
particular interest. The ratio of soluble
solids to acid is increased where potash
is limiting, and is decreased significantly
with increasing applications of potash.
The decrease in the ratio where the

4 -i

t4 o C

-4 00 -
CO t17 0 Ci Ci "!

t_ t-
00 00 000 CO1
00 t- t-w &C C

- ro t- 0C
t'- C D0 CO T
t- C) 11 00 M0

t- 00000 0= I-

^(N *00i
>-! i-l r-ii-^ 0

0 t 00 o
*4 I:- 1 0(
D to LO o

^01 '1I 00
a;> C.; Ta;

0001 q^o

rl? -r^ rcr -*

<000 41O 0O^
I -4I I


potash application has varied between
5 and 10 percent has been significant
some seasons and not in others, Table 4.
In general however, the trend has been
for the ratio of the juice to continue to
decrease with application of potash up
to 10 percent in the fertilizer mixture.
The differences in the time of passing
legal maturity as influenced by these
fertilizer treatments for the past two
seasons are presented in Table 5.
The effect of potassium deficiency and
variable potash application on the vita-
min C content of the juice, follows a pat-
tern very similar to that discussed for
soluble solids. Where potassium is
limited, the vitamin C content of the
juice is significantly decreased. Varia-
tion in the application of potash from
3 through 10 percent has resulted in
slight increases in the vitamin C content
at the higher applications but the differ-
ences are slight (Table 4).
External Quality.-The conclusions
drawn by Eckstein, Bruno and Turren-
tine (8) that potash deficiency is mani-
fested by the production of large, coarse
fruit are apparently incorrect. The re-
ports of investigators working with
oranges, and a previous study by the
author (19) show clearly that small fruit,
with thin rind, and good texture, are
produced where potash is limited. There
has been no consistent difference in the
proportion of Duncan grapefruit meeting
the several standard U. S. Grades, due to
potassium deficiency, or to variations in

the level of potash fertilization. Early
in the season there appears to be a rather
large differential in size of fruit produced
between trees which receive no potash
fertilization and those which do. As the
season progresses this is less apparent,
probably due to the increased number of
drops and the smaller number of fruit
left on the deficient trees. During the
past five years the fruit from the trees
not supplied with potash has averaged
about 0.10 inches smaller in diameter
than fruit from trees supplied with
potash. This is slightly less than the
difference in average diameter between
one commercial size. During the entire
period the fruit from these plots has
always been held late into the season,
which probably accounts for the differen-
tial in size not being greater. No con-
sistent differences in size of fruit pro-
duced has been found to-date where pot-
ash has been applied, even though the
N/KsO ratio has varied from 1-1 to
Production.-Table 6, presents a sum-
mary of the production of fruit as
affected by variations in the level of pot-
ash fertilization during the period from
1940-41 through 1949-50. These data,
based on the average production for the
past nine years, show that the trees re-
ceiving 5 percent potash fertilization
have yielded significantly more fruit than
the trees receiving the other treatments.
The difference between the production
of these trees, and those to which 3 per-


Treatment 1948-49 1949-50
N-P20s-K20-MgO-MnO-CuO Estimated Difference Estimated Difference
N-P2 K2- MnOCuO Date in Days Date in Days
3- 6- 0-3- 1 a/2 September 10 October 15
3 6 3 3 1- 1/2 October 2 22 December 10 56
3 6 5 3 1 1/ October 15 35 January 3 80
3 6 10 3 1 2 October 18 38 January 6 ,83


cent potash is applied, is of greater inter- 4 a t o
est when tree condition as affected by A e- -
previous treatment is considered. The
reports of Ruprecht frequently indicated o 00
that trees receiving the 3 percent potash 1 10
treatment were producing the most fruit
during the period from 1921 until 1936, 0 r- o
with the exception of one year, 1934. c2 M
Further, Camp (3) reported that the
3 percent trees were affected the least
by magnesium deficiency at the time that -1 0 1 C U
the original experiment was stopped,
and corrected, in 1936. Based on previ-
ous performance, the highest production L o $
should be from the trees supplied with
3 percent potash. The indications are
that 3 percent potash, which is equiva- N L C
lent to 1:1 nitrogen-potash ratio at the -
rate of application used, has not been g -
sufficient to maintain production as com- 0 0 -4
pared to the higher 1:1.6 ratio which
corresponds to the 5 percent treatment.
Statistically there is no significant dif- c. a
ference in the production of fruit from o
trees receiving the 0 percent, 3 percent Q S
or the 10 percent potash treatment as i
ascertained by the nine year average. It
is evident from the data, however, that
the production of the trees receiving no L N 0
potash has fallen off badly since the 9 U
1946-47 season, the average yield per g
tree since that time being only 295 -4 a M
pounds. The nine year average value -
for the trees not supplied with potash is
comparatively high by virtue of the fact o o
that these trees were producing heavily > -
during the early part of the experiment. 0

Discussion d -1 0-
Under the present maturity law in
Florida, earliness of maturity for grape-
fruit, once the juice content require-
ments are met, is determined in most
cases by the solids to acid ratio of the -0 6 '
(oI ID Is | | |
juice. Reported earliness of maturity a o o M.
of grapefruit as affected by a low nitro- .
gen to potash ratio (19), together with .o
similar results having been reported for e M


oranges has resulted in a more wide-
spread use of lower nitrogen-potash
ratios in fertilizer mixtures. Ruprecht
reported in 1936 that based on the re-
sults of the potash rate experiment at
that time that there appeared to be no
advantage in using a ratio of nitrogen
to potash higher than 1:1. The fact that
production appears to be falling off in
the plots which are receiving this treat-
ment and that the number of drops is
usually higher than in either the 5 or
10 percent plots would seem to indicate
that this ratio may be too narrow to
obtain maximum yields at the rate of
application used in this experiment.
It should be emphasized that it has
not been possible under the conditions
of this experiment to see immediate
effects from changes in potash fertiliza-
tion either as related to tree condition,
production or fruit quality. The rather
quick responses which have been evi-
dent in citrus from correcting zinc de-
ficiency, or from applications of nitro-
gen have not been observed as a result
of variations in the applications of
potash. Thus, if the lower production
which has been found in this experi-
ment where a 1-1 nitrogen-potash ratio
has been used, may be considered as in-
dicative of what happens under field
conditions generally, the production
may be decreased so gradually in a
commercial grove as to go unnoticed
except by the most discerning growers.
The nitrogen to potash ratio in a
4-6-8-3-1-1/2 fertilizer mixture applied
in the fall and summer applications,
followed by an 8-0-8-6-2-1 spring top-
dresser, is approximately a 1-1.67 ratio
of nitrogen to potash and not a 1-2 as
it is frequently referred to. This cor-
responds to the 5 percent potash ap-
plication used in this experiment which
has to date resulted in the highest
average yields. Even where this ratio
is applied, as was pointed out earlier

by Fudge (19), a large percentage of
the applied potassium is removed an-
nually by the harvested crop. It is of
course, a matter of conjecture as to the
results which might have been obtained
had the rates of application of these
mixtures also been varied but this was
not included in this experiment.

Potassium deficiency under field con-
ditions for Duncan grapefruit was
manifested by slow growth and thin-
ning of the tops of the trees, loss of
young shoots by wind, pre-harvest drop
of fruit and decreased production. The
fruit produced was small in size, with
good texture and thin rind. Internal
quality was characterized by decreased
soluble solids, citric acid and vitamin C
content. Fruit from deficient trees
matured earlier as judged by the soluble
solids/citric acid ratio. The acid con-
tent of the juice increased and the ratio
decreased in fruit produced by trees
supplied with potash applications rang-
ing up to 10 percent in the fertilizer
Continuous use of a 1:1 nitrogen-
potash fertilizer ratio at the rate of
application used in this experiment re-
sulted in decreased yield of fruit as
compared to a 1:1.67 nitrogen-potash
Progress Report of the effects of no potassium
and various sources and amounts of potassium
on citrus. Fla. Sta. Hort. Soc. Proc. 53: 26-38.
2. BRYAN, O. C. Potash deficiency in grapefruit.
Identifying symptoms developed in tests. Florida
Grower. 43(1): 14-16. 1935.
3. CAMP, A. F. A resume of feeding and spraying
citrus trees from a nutritional standpoint.
Fla. Sta. HIort. Soc. Proc. 56: 60-79. 1943.
M., AND PARKER, E. R. Hunger signs in crops.
Judd & Detwiler, Washington, D. C. 267-311.
5. CIAPMAN, H. D., BROWN, M. Analysis of orange
leaves for diagnosing nutrient status with refer-
ence to potassium. HIlgardia. 19: 501-540.


D. S. Some effects of potash deficiency and
excess on orange tree growth, composition and
fruit quality. Calif. Citrograph. 33(7): 278,
279, 290. 1948.
7. COWART, F. F. Effect of source of potash upon
fruit composition. Fla. Agr. Exp. Sta. Ann. Rept.
146-148. 1944.
RENTINE, J. W. Potash deficiency symptoms.
1-235. Illus. Berlin. 1937.
9. FUDGE, B. R. AND FEHMERLING, G. B. Some effects
of soils and fertilizers on fruit composition. Fla.
Sta. Hort. Soc. Proc. 53: 38-46. 1940.
10. Fudge, B. R. Fla. Agr. Exp. Sta. Ann. Rept.
150-152. 1946.
11. HAAS, A. R. C. The growth of citrus in rela-
tion to potassium. Calif. Citrograph. 22(1 & 2):
6, 17, 54, 62. 1936.
12. --................ Potassium in citrus leaves and
fruits. Calif. Citrograph. 22: 154-156. 1937.
13. .......-.. Effect of potassium on citrus
trees. Calif. Citrograph. 33(11): 468, 486,
487, 488, 490. 1948.

14. .......... ..... Potassium in citrus trees. Plant
Physiology. 24: 395-415. 1949.
15. KIME, C. D., JR. Leaching of potash from
sandy citrus soils of Florida. Fla. Sta. Hort.
Soc. Proc. 56: 43-48. 1943.
16. MENAKER, M. H., AND GUERRANT, N. B. Stand-
ardization of 2-6 Dichlorophenolindophenol an
improved method for determination of vitamin
C. Jour. Ind. and Eng. Chem. (Anal.) 10: (1)
25, (5) 269. 1938.
17. Roy, W. R. Effect of potassium deficiency and
of potassium derived from different sources on
the composition of Valencia oranges. Jour. Agr.
Res. 70(5): 143-169. 1945.
18. RUPRECHT, R. W. Effect of potash on com-
position, yield and quality of the crop. Fla. Agr.
Exp. Sta. Ann. Repts. 1922-1936.
19. SITES, JOHN W. Internal Fruit Quality as re-
lated to production practices. Fla. Sta. Hort.
Soc. Proc. 60: 55-62. 1947.
20. WANDER, I. W. (Unpublished Data). Citrus
Experiment State, Lake Alfred, Fla.


Lake Wales
Mr. President, Members of the Florida
Horticultural Society and Guests:
The Executive Committee of the So-
ciety requested that a panel be developed
on Parathion to be presented at this
In planning the panel the assistance of
Dr. J. T. Griffiths, Mr. W. L. Thompson
and Mr. Frank L. Holland was sought.
Due to the keen intellect and efforts of
these three gentlemen, plus the very fine
cooperation of the twenty-two gentlemen
seated before you, we have the panel pre-
pared according to the outline that has
been distributed to you.
These gentlemen, no doubt, are among
the best qualified to speak on Parathion
and its uses that could be found in the
world today. They each have prepared
questions which they are qualified to dis-
cuss intelligently. Many have prepared
questions, they want others in other
fields of work to answer. The opportunity
has been given all of you to submit ques-
tions and many of you have done so.

All of these questions have been sorted
and grouped and will be answered by the
person or persons qualified in that par-
ticular field.
Whether or not the Moderator will
allow questions from the floor will depend
entirely on time. The outline covers all
phases of the subject and we feel that all
phases should be covered rather than too
much time be spent on certain phases
and others neglected.
While Parathion is undoubtedly an out-
standing insecticide, it like all material,
has its limitations. It is expected that
the discussions here today will deal with
the limitations as well as the outstanding
qualities of this material.
On behalf of the Society and personally,
I wish to thank each of you gentlemen
who have helped plan the panel and all of
you who are participating in it.
I now turn the panel over to our most
efficient Moderator, Mr. Frank Holland.
Moderator: We will go right to work
if members of the panel are ready. Be-
fore we get into detailed questions there
is a preliminary question which the mod-


erator will direct to Dr. Bruce D. Gleiss-
ner, Entomologist with the American
Cyanamid Company.
What is Parathion?
Dr. Gleissner: Well, Mr. Holland,
Parathion is an organic phosphate. Ac-
tually the name Parathion is the common
name for the chemical O, O-diethyl-O-
paranitro-phenyl-thiophosphate. Obvi-
ously, you couldn't use such a long chemi-
cal name so they picked Parathion. The
compound was discovered in Germany
but it has been more widely developed
here in the United States for the control
of several hundred economic species of
insects and mites that attack crops grown
in this country.
Moderator: Thank you Dr. Gliessner.
Now, to Dr. Herbert Spencer, Entomol-
ogist with the United States Department
of Agriculture's Subtropical Fruit In-
sects Laboratory at Fort Pierce.
In the USDA experiments, what citrus
pests have been controlled with Para-
Dr. Spencer: The purple scale, Flor-
ida red scale, cloudywinged and citrus
white flies and some of the mealybugs.
The insects and mites that have not been
controlled well are the purple mite and
the rust mite.
Moderator: What materials have you
found compatible with Parathion?
Dr. Spencer: We have found Para-
thion compatible with wettable sulfur,
with coppers and with oil; in fact, with
most of the insecticides and fungicides
except those that are very basic. We
have not used it with liquid lime sulfur
but there is a possibility it can be used
in that combination too.
Moderator: What poundage per 100
gallons of spray gives adequate control
of scale insects?
Dr. Spencer: In our cleanup work for
heavy infestations we are using 2 pounds
of 15% wettable with wettable sulfur.
There is a possibility with light infesta-

tions that two applications spaced over
the year with 1 pound of 15% each time
may keep the infestations to, a very low
Moderator: Thank you Dr. Spencer.
The next questions will be directed to
Mr. W. L. Thompson, Entomologist with
the Citrus Experiment Station at Lake
To obtain scale control, is it necessary
to spray trees as thoroughly with Para-
thion as it is with an oil emulsion?
Mr. Thompson: Yes. Although Para-
thion has some fumigating effect it has
not the same effect that you would ex-
pect from sulfur for rust mite control.
Purple scale control was not satisfactory
where a combination spray containing
Parathion, copper and sulfur was applied
as an outside brushing spray which was
typical of the usual application made for
melanose and rust mite control. The
scales should be covered with Parathion
for satisfactory control.
Moderator: Is Parathion as effective
as oil emulsions for purple and red scale
Mr. Thompson: On a three year aver-
age it has been as effective as oil emul-
sions. However, this year where we have
had an abundance of red scale, there are
more red scale in the tops of the trees
where we sprayed with Parathion than
we have with oil emulsions. On the
average, it has been as satisfactory as oil
Moderator: Are two applications of
Parathion at 1 to 100 as effective as one
application at 2 to 100?
Mr. Thompson: If there is a light to
medium infestation of scale to start with,
two applications of 1 pound of 15% ma-
terial have been as satisfactory as 2
pounds per 100 put on once. In other
words, a Spring application with an-
other application in July or August,
both with 1 pound to the 100, have been
just as satisfactory and in some cases


more so than when the application was
delayed until July or August with 2
pounds to the 100 used.
Moderator: Does purple mite infesta-
tion develop faster following a Parathion
spray than where no Parathion was ap-
Mr. Thompson: There is very little
evidence to show that the effect of Para-
thion increases purple mite. Parathion
does not kill eggs, only the active mites;
therefore, when you have a rather heavy
infestation of purple mites when you
apply the Parathion spray, you can ex-
pect a comparable infestation about two
to three weeks later. Two Parathion
sprays applied at ten day intervals
would probably control purple mites but
that is really not practical.
Moderator: Thank you Mr. Thomp-
son. The next questions will be directed
to Dr. R. K. Voorhees, Associate Horti-
culturist with the Citrus Experiment
Station at Fort Pierce.
What are some of the factors respon-
sible for certain cases,of poor or incon-
sistent citrus scale control with Para-
thion during 1950?
Dr. Voorhees: Some of the factors
responsible for poor scale control with
Parathion, as far as the East Coast is
concerned, are: poor tree coverage for
any reason, but frequently due to windy
weather which also shortens the period
of effectiveness of Parathion; thorough
tree coverage for good scale control is
frequently not obtained with the broom-
type hand spray guns and the boom-
type applicators employed on the coast;
low or minimum concentrations on
heavy scale infestations during any
Moderator: How effective is Para-
thion in reducing scale infestations when
employed at a minimum rate in combina-
tion with the spring melanose sprays?
Dr. Voorhees: In general, good re-
sults have been obtained with Parathion

when combined with the melanose sprays
at the minimum rate of 1 to 11/2 pounds
per 100 gallons. In most cases, this has
reduced light to medium infestations to
the extent that only a minimum dosage
had to be considered during the summer,
and in some cases this second application
was not needed until fall.
Moderator: What are some of the
main factors responsible for accidents
that occurred in connection with the use
of Parathion by citrus spray operators on
the East Coast during 1950?
Dr. Voorhees: In checking on several
authentic cases of Parathion poisoning
to citrus spray operators there were sev-
eral different factors responsible, but no
single factor particularly predominate.
Some of these factors were: negligence
in following the recommended precau-
tions; abnormally low cholinesterase level
of the operator; overexposure from
spraying in windy weather, high summer
temperatures and especially in connec-
tion with heavy canopied groves with
poor air circulation, and from being ex-
posed to Parathion too many days at any
one interval.
Moderator: Thank you Dr. Voorhees.
The next set of questions will relate to
vegetable crops, so as to continue under
Item 1 of the agenda, and will be directed
to Mr. Norman C. Hayslip, Associate
Entomologist with the Everglades Ex-
periment Station at Fort Pierce.
Does Parathion have a place in con-
trolling sweet corn insects?
Mr. Hayslip: The use of Parathion
on sweet corn is still in the experimental
stage; however, we have conducted a
series of studies using Parathion on
sweet corn. It has shown up better than
any other material for the control of the
corn silk fly, killing the adult stage just
before the silks appear, thus preventing
oviposition. On corn earworm, Parathion
at 2% strength in a dust was, in two
experiments, slightly superior to 5%


DDT dust; at 1% it was slightly inferior
to 5% DDT dust. Cage trials indicated
that Parathion has some toxic effect on
adult moths of the corn earworm. The
effect on the adults has not been verified
under field conditions, however. Against
fall armyworms, Parathion is effective
at higher rates of application. That is
to say, 2 pounds of 15% wettable to 100
gallons of water. Parathion also reduces
the damage caused by aphids on corn.
Moderator: In most cases, it has not
been recommended to use Parathion on
vegetables later than 30 days before har-
vest. How does this restriction affect
the use of Parathion on vegetables?
Mr. Hayslip: This question was
phrased to show that such a restriction
is impractical on some crops. One ex-
ample would be tomatoes, which are har-
vested over a period of 40 to 50 days; by
adding 30 days to the first harvest, re-
sults in a period of 70 to 80 days that the
tomato plants are in the field unprotected
by this insecticide, leaving them exposed
for a long period of time to attack by
insects. Other crops of a similar nature
would be peppers and, to some extent,
cucumbers. The question points out the
very serious need for more intelligent
recommendations as to the period of time
elapsing between the last treatment and
harvest; and I am happy to say that I
have just recently learned we are getting
more and more information on the sub-
ject. I was told recently that 21 days is
now the period for most vegetable crops
and, even more recently, that some have
even a smaller lapse of time between
harvest and the last application.
Moderator: Thank you Mr. Hayslip.
I believe that later on in the panel there
will be some further information de-
veloped on that one point. The next ques-
tions will be directed to Dr. E. G. Kel-
sheimer, Entomologist with the Vege-
table Crops Laboratory at Bradenton.
Is Parathion compatible with fungi-

cides and nutrients used in vegetable
Dr. Kelsheimer: Parathion is com-
patible with our dithicarbamates and
copper sprays commonly used on vege-
tables. There is one exception; you
should not use lime in combination with
the carbamate fungicides. It is com-
patible with practically all our insecti-
cides; again, one exception, which is
cryolite. A common practice with us is
to add nutrients to the combination of
insecticidal and fungicidal sprays but we
have evidence to show that an excess of
zinc and iron, and naturally lime, has an
adverse effect on Parathion.
Moderator: What is the best time of
day to apply Parathion on vegetables?
Dr. Kelsheimer: We find that the
best time to apply Parathion is the latter
part of the day and especially after the
dew is off the plants. We have found
that Parathion will cause burn on toma-
toes and cucurbits, such as squash and
cucumber, when the foliage is wet.
Moderator: Thank you Dr. Kelshei-
mer. The next questions will be directed
to Dr. J. W. Wilson, Entomologist at the
Central Florida Experiment Station,
Does Parathion kill insects by fumiga-
tion or is it necessary for the Parathion
to come in contact with the insects to
be effective?
Dr. Wilson: Parathion is capable of
killing insects by acting as a fumigant,
a contact poison or as a stomach poison.
Thus it is not necessary for Parathion
to come into contact with the individual
insects to kill them. But the greatest
benefit from Parathion is obtained when
it is applied to thoroughly cover the
entire leaf surfaces and particularly the
lower surface where most insects are
Moderator: Why is Parathion so
often recommended for use on vegetable
crops in preference to nicotine sulfate?


Dr. Wilson: That question, I think,
refers to the weather conditions under
which vegetable crops are grown in Flor-
ida. Nicotine sulfate requires tempera-
tures of 800 F. and should be applied
when there is little or no air movement
to be most effective. We seldom have
weather conditions favorable for the
most effective use of nicotine sulfate.
Parathion is more effective than nicotine
sulfate under our weather conditions.
Moderator: What information is
available on the residues which may be
found on vegetables following the use of
Dr. Wilson: The residue data avail-
able for Parathion on Florida grown
vegetables are rather meager but the in-
formation we have in conjunction with
information from other sections of the
country indicates that Parathion de-
teriorates rather rapidly. After from
two to four days very little Parathion
remains on the vegetable and after a
period of twelve to fifteen days only
traces of Parathion can be found.
Moderator: Thank you Dr. Wilson.
The next questions will be directed to
Dr. D. 0. Wolfenbarger, Entomologist at
the Sub-Tropical Experiment Station,
Is Parathion satisfactory for control
of soil inhabiting insects?
Dr. Wolfenbarger: Mr. Thames of
the Everglades Experiment Station is
finding it is very satisfactory for use on
the muck soils there for the control of
wireworms. In Perrine marl soils of
Dade county it is a little different story
there, and Parathion has not been effec-
tive in wireworm control on our potato
growing soils.
Moderator: Are any precautions ad-
visable for use of Parathion on leafy
crop plants?
Dr. Wolfenbarger: Yes, that is one
place where we need a great deal of pre-
caution. One of the places of question-

able use of Parathion is on our leafy
vegetables and on our fruits that we eat.
Potatoes, on the other hand, is an ex-
ample of a crop where we don't need to
worry about the residue problem.
Moderator: How frequently need
Parathion applications be made for pest
control on vegetable crops?
Dr. Wolfenbarger: The answer to
that question, I am afraid, is very vari-
able and it will depend to the greatest
extent on your insect infestations. If
you have a very heavy one, you may have
to put it on every five to seven days or so
to combat that infestation. On the other
hand, if your infestation is fairly light,
or incipient, one or two applications may
be satisfactory to control the pests in
that case.
Moderator: Thank you Dr. Wolfen-
barger. The next questions will be di-
rected to Dr. Herbert Spencer, Entomol-
ogist with the U. S. Department of Agri-
culture Sub-Tropical Fruit Insects Labo-
ratory at Fort Pierce. Dr. Spencer,
these two questions deal with subtropical
What pineapple pests have been con-
trolled with Parathion?
Dr. Spencer: The pineapple mealy
bug is the main one, and there is some
evidence that the red spider of pineapple
may be partially controlled with it.
Moderator: How does Parathion com-
pare with DDT for control of little fire
Dr. Spencer: The little fire ants on
subtropical fruits and on citrus can be
controlled by the applications of Para-
thion used for scale control, for a period
of about four months. DDT gives a
longer period of protection. You get
about eight months protection from DDT
on the trunks of the trees, whereas you
get about four months protection against
the fire ants from the Parathion spray
applied with complete coverage.
Moderator: Thank you Dr. Spencer.


Continuing with the subtropical fruits,
Dr. Wolfenbarger.
On what subtropical fruits may Para-
thion we used? For what pests?
Dr. Wolfenbarger: It seems that
Parathion has a very wide use on many
of our subtropical plants, beginning with
the avocado. It has been used on the
avocado for dictospermum scale, in which
case it seems it compares very favorably
with oil emulsion for control of the scale
and then, in addition, there is not the
danger of plant injury. It gets the red
banded thrips on avocados. It gets the
leafrollers and is very effective for many
places, it seems, for avocados. It has
been used on limes, for example, in which
case it is equivalent to oil and, in addi-
tion, there is not the chance for plant
injury there. It has been used on
mangos for lesser snow scale and other
scales on mangos. It would seem to me
that it would have a very widespread use
on the mango for all of its scale pests,
and for the red banded thrips. It is very
effective in those cases. There is one
precaution, when you use Parathion on
mangos or avocados in the season when
you can expect mite infestations, and
that is you had better put in your sulfur
with the Parathion to combat and control
the mite and spider populations. If you
don't, they will build up on the subtropi-
cals, as Mr. Thompson mentioned for
Moderator: What dosages are recom-
mended for use on subtropical fruits?
Dr. Wolfenbarger: About one pound,
the same as is generally used for other
plant pests.
Moderator: The next questions will
be on ornamentals and directed to Dr. L.
C. Kuitert, Entomologist at the Agricul-
tural Experiment Station, Gainesville.
What is the present status regarding
the effectiveness of Parathion sprays in
controlling insect infestations on orna-

Dr. Kuitert: Parathion appears to be
somewhat superior to oil emulsions. It
has the advantage that it can be applied
at seasons of the year when you can't
apply oil emulsions. It will control as
effectively and, in some cases, more effec-
tively most of the insect pests of our
choice ornamentals.
Moderator: In your opinion, can the
home gardener use Parathion safely?
Dr. Kuitert: Yes, I feel they can if
they follow a few simple precautions. I
don't think that a mask will be necessary
if they are very careful in mixing their
insecticides. Most of the home garden-
ers would only apply the material to per-
haps six or eight ornamentals at a time.
The short length of exposure and the in-
frequency of the application would, in my
opinion, be safe for the home gardener.
Moderator: Thank you Dr. Kuitert.
The next questions are directed to Mr. R.
P. Tomasello of the Wilson Spraying
and Supply Co., Inc. at West Palm Beach,
Has Parathion caused any spray injury
to ornamentals?
Mr. Tomasello: Parathion has caused
some injury to Hibiscus, Oleanders,
Aralias and Bougainvilleas. There is a
shedding of the older leaves when Para-
thion has been used at the rate of 11/
pounds of 15% wettable Parathion to
100 gallons of water. This is especially
noticeable when spraying has followed
high winds or if plants suffer from a
lack of adequate moisture or food. Cer-
tain varieties of the above named orna-
mentals appear to be more susceptible
to injury than others.
Moderator: Has any illness been re-
ported by home owners following the
use of Parathion on foundation plantings,
Mr. Tomasello: Because we are aware
of the potential dangers of Parathion, a
careful check has been made of the homes
where this material has been used. We


have been using Parathion approximately
two years and during this time there has
not been a single report by home-owners
of illness following its use on foundation
Moderator: That completes Part I of
our questions. We will now proceed to
Part II, dealing with practical considera-
tions for growers in field use. The next
questions will be directed to Mr. Wilbur
Charles, Production Manager of the
Florence Citrus Growers Association of
Florence Villa.
What precautions should be used to
protect the user of Parathion from
Mr. Charles: We have equipped our
men with coveralls and masks. We have
not adopted the use of rubber gloves.
Moderator: How do the growers liv-
ing in groves feel about using Parathion
near their homes?
Mr. Charles: We have several grow-
ers of the association living in their
groves. When we started using Para-
thion each of these were consulted as to
whether we were to use this material
around their houses or not. In each
case, the grower consented, in fact, he
now asks us to use it around the house
the same as any other insecticide.
Moderator: What changes in the
groves have been observed, if any, from
the use of Parathion as compared to oil?
Mr. Cl..e'i. -: The outstanding effect
that I think I see from the use of Para-
thion is in the older groves, such as we
have in this section. The older groves
that have been here since the early
1900s, I feel, were beginning to show a
great toxicity to the use of oils. Since
we have been using the Parathion, I see
a great improvement in the condition of
the groves. This I know is not due to
any change in fertilizer because the fer-
tilizer program has been the same. We,
of course, have had dry weather to com-

bat but, even with that, the groves are
in better physical condition.
Moderator: Thank you Mr. Charles.
We will next hear from Mr. Willard D.
Miller, chairman of the research com-
mittee of the Florida Fruit and Vegetable
Association at Ruskin, Florida.
What effect has sunshine and rain on
removing any objectionable residue from
Mr. Miller: That is a question, Mr.
Moderator, that I have asked someone
else to answer for me. I want to hear
from somebody who is qualified to an-
swer it.
Moderator: We will be glad to direct
it to some other member of the panel.
Mr. Miller: If you please.
Moderator: Alright. The next ques-
tion here may also fall into that category.
You be frank and say so if it does.
How close to picking time can Para-
thion be used on the following vegetables
without danger of having excess residue
which may be questioned by the Pure
Food and Drug Administration? Now
there are four or five vegetable crops
listed. The moderator would be inclined
to guess you would want that question
to lay over to Dr. Gleissner who is going
to discuss the answer to questions on
the status of Food and Drug hearing.
Mr. Miller: Yes, you asked me to be
frank; that was another one that I
wanted somebody else to answer for me.
Moderator: Thank you Mr. Miller.
Now, while we are on this subject, I want
to ask Dr. Gleissner a question on this
very interesting subject.
Have the manufacturers of Parathion
recommended any certain amount of
residue that they feel can remain on a
vegetable without injury to the con-
Dr. Gleissner: Yes sir. Both the
manufacturers of Parathion and repre-
sentatives of the Food and Drug Admin-
istration presented data at the Food and


Drug Administration hearings to the
effect that a residual level somewhere
between two and five parts per million
would not be hazardous to consumers.
The American Cyanamid Company
placed data in the record which indicated
that even a considerably greater residual
tolerance could be allowed and still be
conservative but under the conditions of
the uses of Parathion, two to five parts
is the largest that will ever be necessary.
Moderator: Thank you. I wonder if
I might ask another one of these ques-
tions to Dr. Kelsheimer or Dr. Wolfen-
What effect has sunshine and rain on
removing any objectionable residue of
Dr. Kelsheimer: What meager records
we have show that Parathion is broken
down very quickly under our sunlight
conditions. Do you want the rainfall?
Moderator: Yes.
Dr. Kelsheimer: The rainfall also
tends to wash off this residue.
Moderator: Thank you. I see there
is another question, Dr. Kelsheimer,
which has been answered in part. The
question is as follows:
How close to picking time can Para-
thion be used on the following vegetables
without danger of having excess residue
which may be questioned by the Pure
Food and Drug Administration? The
commodities are tomatoes, cucumbers,
peppers and leaf crops such as cabbage
and lettuce. Do you think that has been
answered or do you care to comment?
Dr. Kelsheimer: I believe that has
been answered.
Moderator: Thank you. The next
questions will be directed to Mr. J. J.
Taylor of the State Department of Agri-
culture from Tallahassee, Florida, on
State Label, Package and Control data.
Are there adequate methods for deter-
mining Parathion?
Mr. Taylor: Yes. There are a num-

ber of methods for determining Para-
thion. The method we use in our labora-
tory is the colorimetric method, which
was developed by Averill and Morris for
residues of Parathion modified to use
for dust formulations. There are a num-
ber of other methods in use but we have
found this to be the most satisfactory
and that is the one we use for regulatory
Moderator: Have you found accurate
methods for both concentrate and dilute
Mr. Taylor: Yes. The method is ac-
curate both for concentrate and dilute
mixtures. It is, of course, more accurate
in the smaller amounts; possibly ac-
curate in the 15 and 25 percent concen-
trates to something like a one-half or
one quarter of 1%.
Moderator: Do you find that Para-
thion mixtures usually come up to their
Mr. Taylor: For the most part
Parathion mixtures meet their guaran-
tees. A few have failed to do so. We
found most of the companies put up their
15 and 25 percent concentrate in tin con-
tainers. For 1 percent dust, some com-
panies use paper bags with inner lin-
ings; some, containers with tin top and
bottom and cardboard sides. These seem
very satisfactory but even some of the
paper bags with inner linings don't seem
to hold the dust in too well.
Moderator: Thank you Mr. Taylor.
We will now have Section III, Citrus
Fruit Quality Factors. The questions
are directed to Dr. Paul L. Harding,
Fruit and Vegetable Handling, Trans-
portation and Storage Investigations,
U. S. Department of Agriculture, Orlan-
do, Florida.
Is Parathion spray superior to oil in
increasing the total solids content wheth-
er applied in either June or August, or
at both times?
Dr. Harding: A few years ago the


Bureau of Entomology and Plant Quar-
antine and the Bureau of Plant Industry,
both of the U. S. Department of Agricul-
ture, set up experiments to determine the
effect of oil and Parathion sprays on the
composition of oranges. During the first
two years the work was on Valencia
oranges. Emphasis during the last two
years has been on early oranges with the
tests being made on the varieties Parson
Brown and Hamlin. The results of these
studies show: A. That Parathion is defi-
nately superior to oil in increasing the
total solids content whether applied in
June or August or at both times. B. That
oil applied in June does not seem to have
a depressing effect on total solids con-
tent. C. That oil applied in August has
a very depressing effect on total solids.
Moderator: Did your studies show
that Parathion increased the total solids
content over the controls?
Dr. Harding: The question is asked,
"Did Parathion definitely stimulate or
give a definite increase in total solids
over the control?" When we compare
Parathion applied in June and August
with the controls we find that there is a
difference of .23 which tells us there is
a significant difference between the con-
trol and Parathion applied in June and
August. We can similarly establish the
fact that oil sprays depress the total
solids level by comparing the treatment
of oil applied in August, or the treat-
ment of oil applied in June and August,
with the control. To summarize our
findings, our results show that single
applications of Parathion applied in June
or in August did not significantly affect
the total solids content when compared
with the controls. On the other hand,
two applications of Parathion, one ap-
plied in June and the other in August,
did significantly increase total solids.
Moderator: What is the general ef-
fect of oil and Parathion sprays on Vita-

min C, total acid, and the degreening of
Dr. Harding: The ascorbic acid (Vita-
min C), and the total acid content of the
fruit was slightly depressed by the ap-
plication of oil sprays. The differences
were small and the decrease generally re-
sulted from the applications of oil in
August. Parathion sprays had very
little effect on Vitamin C and the results
indicate a very slight increase when our
data are compared with the control fruit.
The results are of interest from a scien-
tific point of view but it should be pointed
out that the increase is too small to be
of practical value. The effect that various
sprays have on the degreening of fruit
or on the color of the rind is of im-
portance to the citrus grower and ship-
per. It was, therefore, of considerable
interest to find that the fruit which we
sprayed with Parathion should degree
at an earlier date than the fruit from
either the oil or controlled plots. The
brighter color of the fruit from the
Parathion plots appeared to persist into
the stage of over-ripeness, however the
differences among treatments are not
so marked when the fruit is completely
degreened. Our results show that the
late oil sprays applied in August are
largely responsible for the depressive
effect in total solids, total acid and Vita-
min C, as well as the failure of the fruit
to degree as early as when sprayed with
Parathion. I wish to emphasize that the
early (June) applications of oil had very
little deleterious effect on fruit composi-
tion or on the rind color of the fruit.
Moderator: Thank you Dr. Harding.
Dr. J. W. Sites, Horticulturist with the
Citrus Experiment Station, Lake Alfred,
Florida, the next set of questions will
be directed to you.
Have appreciable differences in the
soluble solids content of the juice of fruit
from trees, sprayed with Parathion as


contrasted to trees sprayed with oil at the
same time, been found?
Dr. Sites: Yes. Very appreciable
differences have been found. Of course,
the magnitude of these differences de-
pends on the time of the application of
the oil spray. Where we checked groves
throughout the state last year, for ex-
ample, the differences, where we were
comparing Parathion sprays to oil sprays
applied about the middle of June varied
between three-tenths Brix unit and one
Brix unit.
Moderator: Does the rate of appli-
cation of Parathion affect the soluble
solids content of the fruit?
Dr. Sites: The work which we have
done thus far indicates that the rate of
application has practically no effect on
the soluble solids content of citrus.
Moderator: Is the use of Parathion
in place of oil sprays for scale control
equally effective for all varieties in so
far as the quality of the fruit produced
is concerned?
Dr. Sites: So long as one is compar-
ing Parathion against oil sprays it would
have to be stated that you cannot expect
the same effect for the use of Parathion
for all varieties. The reason for this is
not that the Parathion is less effective
on certain varieties, but rather that oil
sprays do not cause the same effect con-
sistently for all varieties. Because oil
sprays usually do not cause as severe
lowering of the soluble solids content in
grapefruit as in oranges, it follows that
one could not expect as much increase in
the soluble solids content of grapefruit
varieties where Parathion was used in
place of oil sprays.
Moderator: Is there any reason to be-
lieve that the use of Parathion sprays
will result in the production of fruit with
a higher soluble solids content than would
have been produced had no sprays for
scale control been applied?
Dr. Sites: That question goes back

to the fact it was more or less intimated
early in the use of Parathion that bene-
fits were being gained by its use over
and above the limitations set by the
generic pattern of the tree itself. I do
not believe that is true.
Moderator: Thank you Dr. Sites.
Part IV is Processed Citrus Products
Factors. The field of Molasses and Feed
will be addressed to Mr. R. N. Hendrick-
son, Assistant Chemist at the Citrus Ex-
periment Station, Lake Alfred, Florida.
Has Parathion been found in citrus
pulp or citrus molasses and, if so, in
what quantity?
Mr. Hendrickson: Citrus pulp and
molasses made from grapefruit peel
sprayed with 25/100 pounds active
Parathion per 100 gallons was found to
have approximately one part per million
in the dried feed and one-half parts per
million in the molasses. The Parathion
content of the wet peel in this instance
was considered to be an average value.
Moderator: Is the quantity of Para-
tion present in feed and molasses harm-
ful to dairy or beef cattle?
Mr. Hendrickson: Feeding trials at
the Kansas Agricultural Experiment
Station where dairy cattle were fed five
parts per million on a total feed basis
for 81 days and thereafter slowly in-
creased to 40 parts per million, showed
the Parathion as having no harmful
effect on the health of the cow. No
Parathion was found in the milk, nor
any objectionable off flavors. Coopera-
tive studies between the University of
Illinois, a large packing company and
the American Cyanamid Company, in
which beef animals consumed five parts
per million actual Parathion, based on
the silage intake of their diet for 100
days finishing period, showed no Para-
thion in the fat, lean meat, or liver
tissue at the time of slaughter.
Moderator: Thank you Mr. Hendrick-
son. The next questions on peel oil will


be addressed to Mr. J. W. Kesterson, As-
sociate Chemist at the Citrus Experiment
Station, Lake Alfred, Florida.
Where is Parathion found in the citrus
fruit and in what concentrations?
Mr. Kesterson: The oil cells are the
only part of the fruit in which the Para-
thion is retained. In 23 samples of cold-
pressed oil studied this year, for both
orange and grapefruit the concentration
of Parathion was found to range from 0
to 236 parts per million. In 75 percent
of the samples, the range was 0 to 60
parts per million.
Moderator: Does the presence of
Parathion in a coldpressed citrus oil
harm the oil?
Mr. Kesterson: No. The presence of
Parathion did not show any noticeable
influence on the physical or chemical
characteristics of the oil. Warburg
respirometer studies to determine the
keeping quality or oxidative stability of
the oil showed Parathion to have the
beneficial effect of slightly increasing the
stability of the oil.
Moderator: Thank you Mr. Kester-
son. The next questions relate to
Residues in Citrus Products and will be
addressed to Mr. C. R. Stearns, Jr., As-
sociate Chemist at the Citrus Experiment
Station, Lake Alfred, Florida.
Does the Parathion penetrate through
the peel and contaminate the juice por-
tion of the fruit?
Mr. Stearns: No. In reemphasizing
Mr. Kesterson's statement, the Parathion
does not penetrate through the peel of
the fruit.
Moderator: If Parathion is present
in the peel, will the juice expressed by
different commercial extractors be con-
taminated with Parathion?
Mr. Stearns: In some cases we have
found very small amounts of Parathion;
however, these values present no health
hazard and therefore are of no conse-

Moderator: Thank you Mr. Stearns.
The next questions, related to Canned
Citrus Products, are addressed to Mr. R.
W. Olsen, Biochemist at the Citrus Ex-
periment Station, Lake Alfred, Florida.
Does Parathion sprayed on groves have
any effect on flavor or keeping quality
of canned citrus?
Mr. Olsen: We found no difference
in flavor between the Parathion sprayed
fruit and the control in freshly extracted
juice or, upon storage, of the finished
Moderator: What happens to the
Parathion, if any is present, during pro-
Mr. Olsen: Orange juice containing
Parathion lost up to 48 percent of the
Parathion during the processing of single
strength orange juice and up to about 25
percent in the manufacture of frozen
Moderator: Thank you, Mr. Olsen.
Part V on the program relates to Human
Health Aspects with Reference to Fac-
tory and Field Workers: Safety Precau-
tions; Preventive Measures: Practical
and Professional Steps that have Been
Developed and Are Important to Em-
ployer and Employees; Residues; Air
Contamination; Public Health and In-
dustrial Commission Considerations. The
first questions will be directed to Dr.
John W. Williams, Pathologist at Mor-
rell Memorial Hospital, Lakeland, Flor-
ida, relating to indications of suscepti-
bility, coupled with symptoms and treat-
Should individuals about to work with
Parathion be given medical examination?
If so, why? And are there any specific
examinations indicated?
Dr. Williams: The answer is yes. In-
dividuals about to work with Parathion
should be given medical examinations. It
is important to determine whether the
individual is a psychoneurotic or not. If
the grower employs a psychoneurotic, he

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