• TABLE OF CONTENTS
HIDE
 Front Cover
 Title Page
 Credits
 Letter of transmittal
 Main
 Index














Group Title: Annual report, University of Florida. Agricultural Experiment Station.
Title: Annual report for the fiscal year ending June 30th ...
ALL VOLUMES CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027385/00022
 Material Information
Title: Annual report for the fiscal year ending June 30th ...
Series Title: Annual report for the fiscal year ending June 30th.
Alternate Title: Florida Agricultural Experiment Stations annual report
Physical Description: 23 v. : ill. ; 23 cm.
Language: English
Creator: University of Florida -- Agricultural Experiment Station
Publisher: The Station
Place of Publication: Gainesville Fla
Publication Date: 1936
Frequency: annual
regular
 Subjects
Subject: Agriculture -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
 Notes
Statement of Responsibility: University of Florida, Gainesville, Florida, Agricultural Experiment Stations.
Dates or Sequential Designation: 1931-1967.
 Record Information
Bibliographic ID: UF00027385
Volume ID: VID00022
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AMF8114
oclc - 12029671
alephbibnum - 002452809
lccn - sf 91090332
 Related Items
Preceded by: Report for the fiscal year ending June 30th ...
Succeeded by: Annual research report of the Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Page 1
    Credits
        Page 2
    Letter of transmittal
        Page 3
        Page 4
    Main
        Page 5
        Page 6
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
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        Page 18
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        Page 21
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        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
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        Page 35
        Page 36
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        Page 157
        Page 158
        Page 159
        Page 160
        Page 161
        Page 162
    Index
        Page i
        Page ii
        Page iii
        Page iv
        Page v
        Page vi
        Page vii
        Page viii
        Page ix
Full Text






























































..........


A41"











UNIVERSITY OF FLORIDA
GAINESVILLE, FLORIDA



AGRICULTURAL EXPERIMENT

STATION





.Annual Report
FOR THE FISCAL YEAR ENDING
June 30, 1936








EXECUTIVE STAFF

John J. Tigert, M.A., LL.D., President of
the University
Wilmon Newell, D.Sc., Director
H. Harold Hume, M.S., Asst. Dir., Research
Harold Mowry, M.S.A., Asst. Dir., Adm.
J. Francis Cooper, M.S.A., Editor
Jefferson Thomas, Assistant Editor
Clyde Beale, A.B.J., Assistant Editor
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant

MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist**
W. A. Leukel, Ph.D., Agronomist
G. E. Ritchey, M.S.A., Associate*
Fred H. Hull, Ph.D., Associate
W. A. Carver, Ph.D., Associate
John P. Camp, M.S., Assistant
ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Dairy Husbandman
W. M. Neal, Ph.D., Asso. in An. Nutrition
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian
N. R. Mehrhof, M.Agr., Poultry Husbandman
W. W. Henley, B.S.A., Asst. An. Husb.*
W. G. Kirk, Ph.D., Asst. An. Husbandman
R. M. Crown, M.S.A., Asst. An. Husbandman
P. T. Dix Arnold, B.S.A., Assistant Dairy
Husbandman
L. L. Rusoff, M.S., Laboratory Assistant
Jeanette Shaw, M.S., Laboratory Technician
CHEMISTRY AND SOILS
R. W. Ruprecht, Ph.D., Chemist**
R. M. Barnette, Ph.D., Chemist
C. E. Bell, Ph.D., Associate
R. B. French, Ph.D., Associate
H. W. Winsor, B.S.A., Assistant
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economist**
Bruce McKinley, A.B., B.S.A., Associate
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Assistant
ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist"*
C. F. Ahmann, Ph.D., Physiologist
ENTOMOLOGY
J. R. Watson, A.M., Entomologist**
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
A. F. Camp, Ph.D., Horticulturist"*
G. H. Blackmon, M.S.A., Horticulturist and
Associate Head of Department
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph.D., Truck Horticulturist
R. J. Wilmot, M.S.A., Specialist, Fumigation
Research
R. D. Dickey, B.S.A., Assistant Horticulturist
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist**
George F. Weber, Ph.D., Plant Pathologist
R. K. Voorhees, M.S., Assistant***
Erdman West, M.S., Mycologist
Lillian E. Arnold, M.S., Assistant Botanist
Stacy O. Hawkins, M.A., Assistant Plant
Pathologist
SPECTROGRAPHIC LABORATORY
L. W. Gaddum, Ph.D., Biochemist
L. H. Rogers, M.A., Spectroscopic Analyst


BOARD OF CONTROL
Geo. H. Baldwin, Chairman, Jacksonville
Oliver J. Semmes, Pensacola
Harry C. Duncan, Tavares
Thomas W. Bryant, Lakeland
J. T. Diamond, Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
L. O. Gratz, Ph.D., Plant Pathologist in
Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
J. D. Warner, M.S., Agronomist
Jesse Reeves, Farm Superintendent
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in Charge
John H. Jefferies, Superintendent
Michael Peech, Ph.D., Soils Chemist
W. A. Kuntz, A.M., Asso. Plant Pathologist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asst. Entomologist
EVERGLADES STATION, BELLE GLADE
A. Daane, Ph.D., Agronomist in Charge
R. N. Lobdell, M.S., Entomologist
F. D. Stevens, B.S., Sugarcane Agronomist
Thomas Bregger, Ph.D., Sugarcane Physiologist
G. R. Townsend, Ph.D., Assistant Plant
Pathologist
J. R. Neller, Ph.D., Biochemist
R. W. Kidder, B.S., Assistant Animal
Husbandman
Ross E. Robertson, B.S., Assistant Chemist
B. S. Clayton, B.S.C.E., Drainage Engineer*
SUB-TROPICAL STATION, HOMESTEAD
H. S. Wolfe, Ph.D., Horticulturist in Charge
W. M. Fifiel M.S., Asst. Horticulturist
Geo. D. Ruehle, Ph.D., Associate Plant
Pathologist
W. CENTRAL FLA. STA., BROOKSVILLE
W. F. Ward, M.S.A., Asst. An. Husbandman
in Charge*


FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Pathologist in
Charge
W. B. Shippy, Ph.D., Asso. Plant Pathologist
K. W. Loucks, M.S., Asst. Plant Pathologist
J. W. Wilson, Ph.D., Associate Entomologist
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Cocoa
A. S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Pathologist
Monticello
G. B. Fairchild, M.S., Asst. Entomologist***
Bradenton
David G. Kelbert, Asst. Plant Pathologist
C. C. Goff, M.S., Assistant Entomologist
Sanford
E. R. Purvis, Ph.D., Assistant Chemist
Celery Investigations
Lakeland
E. S. Ellison, Ph.D., Meteorologist*
B. H. Moore, A.B., Asst. Meteorologist*
In cooperation with U.S.D.A.
** Head of Department.
*** On leave.











LIST OF DEPARTMENT REPORTS
Page
Report of the Director ............ ... ....................... ...................................... .. ... 5
Report of Business M manager ..... ........... .............. ...... ... ............................................................. 15
Editorial and M ailing D epartm ent ................................ ......................... ................... 22
Library ................................................................................ ............. .. 29
Agricultural Econom ics ................ .................................... ........................................... .............. ........... 30
A gronom y .......................................................... ............... ......................................... .. 36
Anim al Husbandry .............................. ...... ................................................... .... .................... 47
Chemistry and Soils ............... ..................................... ......... ... ..... .... ... ....... 58
Entomology .............. ........................................................ 64
H om e E conom ics ........................................ .................................. .......... .... ........... ....... ..... 70
H horticulture ................................................................................................................... ..... .................. 73
P lant P anthology ......................................... .................................. .... ......................... ............... 85
Spectrographic L laboratory ............. ................... .................. ....................... ............... .. ...... 97
Federal-State Horticultural Protection Service ............................. .......................... 99
Citrus Station ............................................................... ............. ................................. ................. .... 107
Everglades Station ...................... ........ .. ...... ... ......... ............ .. 115
North Florida Station .......................................................... ............... ... .... 141
Subtropical Station ............................. ........ ......... ... ........... 148
W est Central Florida Station ... ........................ .. ....................................... ..... ........... ....... 155








Hon. Dave Sholtz,
Governor of Florida,
Tallahassee, Florida.

SIR: I have the honor to transmit herewith the annual report of the
Director of the University of Florida Agricultural Experiment Stations
for the fiscal year ending June 30, 1936.
Respectfully,
GEORGE H. BALDWIN,
Chairman, Board of Control.







Hon. George H. Baldwin,
Chairman, Board of Control.

SIR: I have the honor to transmit herewith the annual report of the
Director of the University of Florida Agricultural Experiment Stations
for the fiscal year ending June 30, 1936, and I request that you transmit
the same, in accordance with law, to His Excellency, the Governor of
Florida.
Respectfully,
JOHN J. TIGERT,
President, University of Florida.









JLLY AUGJ15 SEPrTEM8ER OCfOBERA IRIZCLMBA2 Jyq4.f Pe54Ifily. "AIC A '4 IqA5


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1.-Graph showing rainfall and evaporation and maximum and minimum temperatures for the year at the
Everglades Experiment Station.


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Report for the Fiscal Year Ending

June 30, 1936






Hon. John J. Tigert,
President, University of Florida.
SIR: I have the honor to transmit herewith my report on the work and
investigations of the University of Florida Agricultural Experiment Sta-
tions, together with the reports of the heads of the several departments,
for the fiscal year ending June 30, 1936.
Respectfully,
WILMON NEWELL,
Director.


INTRODUCTION
Activities of the Agricultural Experiment Stations for the fiscal year
were enlarged somewhat over the previous one with a much needed increase
in the investigational work at the Citrus branch station; the establishment,
in cooperation with the United States Weather Bureau, of a frost fore-
casting service for citrus and trucking areas; and the inauguration late
in the year of a comprehensive project on pasture research.
As in previous years the four branch stations and seven field labora-
tories have been maintained and active cooperation involving a wide pro-
gram of coordinated research in agriculture has been carried with other
state agencies, the federal West Central Florida Experiment Station at
Brooksville, and various divisions of the United States Department of Agri-
culture. The Station also has continued to participate actively in recovery
and readjustment programs, especially in the field of agricultural economics.
The lines of work and accomplishments of each of the departments and
branch stations are briefly reviewed under their respective headings on
the following pages. These summaries, together with the bulletins and
other publications of staff workers appearing during the year, demonstrate
the extent and diversity of the research program and the material ad-
vancement made in all of the several fields of investigation.

LAND ADDITIONS AND IMPROVEMENTS
An additional tract of land, comprising some 175 acres and adjoining
University properties, was purchased in May 1936. These lands will be
used for the most part in pasture investigations.
Building construction at the Main Station for the year was confined
to a small farm shop, a poultry laboratory, and the conversion of one of
the barns into an animal nutrition laboratory.
Overhead irrigation was installed on approximately four acres of the
experimental truck crop plots.







6 Florida Agricultural Experiment Station

CHANGES IN STAFF
Changes in Station staff during the fiscal year were as follows:
H. W. Jones, assistant chemist, resigned July 1, 1935.
L. L. Rusoff was appointed laboratory assistant July 1, 1935.
Jeanette Shaw was appointed laboratory technician July 1, 1935.
C. F. Ahmann, physiologist, was granted an extension of leave from
July 1 to September 26, 1935, to complete his graduate studies.
E. S. Ellison was appointed meteorologist August 16, 1935.
Thomas Bregger was appointed plant physiologist, sugarcane, Septem-
ber 1, 1935.
G. B. Fairchild, assistant entomologist, was granted one year's leave
of absence from October 15, 1935, to pursue entomological studies with
the Rockefeller Foundation in South America. He resigned May 26, 1936.
R. E. Nolen, assistant plant pathologist, resigned August 31, 1935.
R. K.' Voorhees, assistant plant pathologist, was granted leave of
absence from October 15, 1935, to June 30, 1936, to pursue graduate studies.
R. M. Crown, assistant agronomist at the North Florida Station, was
transferred to the position of assistant animal husbandman at the Main
Station, November 18, 1935.
Bernard H. Moore was appointed assistant meteorologist November
1, 1935.
Milton L. Blanc was appointed assistant meteorologist for the period
November 16, 1935, to March 31, 1936.
Warren O. Johnson was appointed assistant meteorologist for the
period November 14, 1935, to March 31, 1936.
Ray T. Sherouse was appointed assistant meteorologist for the period
November 15, 1935, to March 31, 1936.
Geo. D. Ruehle, associate plant pathologist, was transferred from the
Citrus Station to the Subtropical Station December 1, 1935.
A. F. Camp was appointed horticulturist in charge, Citrus Experiment
Station, with transfer of headquarters from the Main Station to the
Citrus Station December 15, 1935.
G. H. Blackmon was appointed associate head, Department of Horti-
culture, December 15, 1935.
Bradford Knapp, Jr., assistant animal husbandman, resigned January
31, 1936.
W. G. Kirk was appointed assistant animal husbandman February 17,
1936.
Stacy 0. Hawkins, assistant plant pathologist, was transferred from
the Subtropical Station to the Main Station March 1, 1936.
Michael Peech was appointed soils chemist at the Citrus Station June
15, 1936.
R. V. Allison, soils specialist in charge, Everglades Station, resigned
June 30, 1936.







Annual Report, 1936


FINANCIAL RESOURCES
Financial resources, from both Federal and State appropriations, of
the Agricultural Experiment Stations for the fiscal year ending June 30,
1936 were as follows:
Federal Hatch fund ....... ...... .................. ...................$ 15,000.00
Federal Adams fund .......................... ............... ................... 15,000.00
Federal Bankhead-Jones fund .............................- .................... 7,700.41
State funds
M ain Station .................................................................. .................... 239,603.00
Including Field Laboratories as follows:
Tomato Disease Investigations, Bradenton ........$ 2,900.00
Strawberry Investigations, Plant City .............. 6,300.00
Citrus Diseases, Cocoa .......................................... 3,500.00
Potato Disease Investigations, Hastings ............ 4,000.00
Laboratory at Hastings ........................................ 5,250.00
Pecan Insect Investigations, Monticello ............ 4,150.00
Celery Investigations, Sanford ............................ 5,250.00
Fumigation Research .......................................... 3,062.50
Grape Pest Investigations .................................... 3,500.00
Citrus Experiment Station, Lake Alfred ........................................ 46,451.00
Everglades Experiment Station, Belle Glade ................................ 50,339.00
North Florida Experiment Station, Quincy .................................... 25,968.00
Subtropical Experiment Station, Homestead ................................ 10,579.00
W atermelon Laboratory, Leesburg ..................................-............... 7,000.00
Frost Forecasting Service, supplementing Federal funds ............ 10,000.00
Other Federal funds, not included above .....-.. --.............................. 60,000.00

SCOPE OF INVESTIGATIONS
The research projects carried during the fiscal year, grouped under
the respective departments and branch stations and with page reference
to a discussion of each, are listed on the following seven pages.












Department
AGRICULTURAL
ECONOMICS










AGRONOMY


LIST OF PROJECTS UNDER INVESTIGATION DURING THE YEAR

Number Title P
73 Agricultural Survey of Some 500 Farms in the General Farming Region of North-
west Florida ---........ .. .................... ...... .......................... ....................------
154 Farmers' Cooperative Associations in Florida ........................ ..... ............ ..... .....
186 Cost of Production and Grove Organization Studies of Florida Citrus ........................
235 A Study of Pre-cooling and of Refrigeration in Transit as Affecting Cost of
Marketing, Quality and Price of Citrus Fruit ................... .................................
248 Farm Taxation ................. ................................... .... .... ......
262 A Study of Adjustments in Farming by Regions and Type-of-Farming Areas,
from the Standpoint of Agricultural Adjustment and Planning, Including
Soil Conservation ........................................ ..... .... ..... ........ .... ..
None Absentee Ownership of Citrus Properties in Florida .........................................----
None Florida Truck Crop Competition ..........................................................


20
27
55
56
83
98
105
107
120
153

159
163
174
220
243

265

267
None


Plant Breeding- Peanuts ....................-....... ..... ....-------..-..----- -.......-- .............
Pasture Experim ents ......................................................... ..-.... ..... ....................... ...
Crop Rotation Studies with Corn, Cotton, Crotalaria and Austrian Peas ..................
Variety Test W ork with Field Crops ............................................... ..............................
Cover Crop and Green Manure Studies in Citrus Groves ...........................................
Green M anure Studies ......................................................... ......................................... .
Improvement of Corn by Selection and Breeding ............................. ......................
Crop Adaptation Studies ....................................... ........ ...................... ..........
Fertilization of Pasture and Forage Grasses .................................. ..................... .....---
Date of Seeding and Phosphate Requirements of Winter Legumes and their
Effect upon Subsequent Crops ........................................................ ....................
Ratio of Organic to Inorganic Nitrogen in Mixed Fertilizer for Cotton ....................
Corn Fertilizer Experim ents .............................................................................................
A Study of Crotalaria as a Forage Crop ...................................................... ..........
A Study of Chlorosis in Corn Plants and Other Field Crop Plants .........................
A Study of the Development and Deterioration of Roots in Relation to the Growth
of Pasture Plants Grown under Different Fertilizer and Cutting Treatments
Composition Factors Affecting the Value of Sugarcane for Forage and Other
P purposes ........................... ... .. ..................... ... ...........................................
Pasture Studies ......................................... ................. ......... .................... ...................
Preliminary Stack Silo Experiments ...................... .......... .............................


age

30
30
30

32
32

33
34
35

36
37
38
39
40
40
40
42
42

43
43
43
43
44

44

45
45
45






Department
AGRONOMY
(Continued)


ANIMAL
HUSBANDRY


Number
None

None
None


244

245

246

250

251
258
None


Title
Comparative Production of Several Silage
ity L evels ........................................ ..
Chufa Fertilizer and Spacing Tests ..........
Sea Island Cotton ....................................


Page
Crops Grown at Relatively High Fertil-
.................... ................................................. 4 5
. ............ .......................................-- .....--...... 46
.. ......................................... .......................... 46


Deficiencies in Feeds U sed in Cattle Rations ........................... ........................................
Comparison of Various Grazing Crops with Dry Lot Feeding for Pork Production
Relation of Conformation and Anatomy of the Dairy Cow to Her Milk and Butter-
fat Production ..................................................................................
Fattening Fall Pigs for Spring Market .... ................................ .............................
A Study of the Feeding Value of Crotalarias ................. ..............................
Swine Field Experim ent ........... ...... ........................................ ................................
A Study of the Ensilability of Florida Forage Crops .......................................
Beef Cattle Breeding Investigations ........................ ...............................
Cooperative Field Studies with Beef and Dual-Purpose Cattle .....................-..........
Dual-Purpose Cattle Investigations under Farm Conditions ---.......................----..-..
Factors Affecting the Percentage of Calf Crop and Size of Calves .................
Beef and Dual-Purpose Cattle Investigations ............--- .......................
Investigations of Hemorrhagic Septicemia in Cattle and Swine ......................
The Digestible Coefficients and Feeding Value of Dried Grapefruit Refuse and
Dried Orange Refuse .............. .......................- ...........................
The Efficiency of the Trench Silo for Preservation of Forage Crops as Measured
by Chemical Means and by the Utilization of the Nutrients of the Silage
by C battle .........................................................................................................
A Comparative Study of Corn and Liquid Milk Versus a Grain and Mash Ration
in Feeding for Egg Production ......... ..................................................
A Comparative Study of the Value of Meatscraps, Fish Meal, and Milk Solids as
Sources of Protein for Egg Production .................. ...........................
Lights Versus No Lights for Egg Production on Single Comb White Leghorn
Pullets and H ens .............................. ...... ..----........................
Effect of. Feeding Colon Organisms and Dried Whey on the Bacterial Flora of
Baby Chicks Affected with Pullorum Disease ........... ................................
The Etiology of Fowl Paralysis, Leukemia and Allied Conditions in Animals ........
A Study of Plants Poisonous to Livestock in Florida ......................................-
Deficiencies of Peanuts When Used as a Basal Ration for Swine ..................








Department
CHEMISTRY
AND SOILS












ENTOMOLOGY












HOME ECONOMICS


Number
22

37

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220
223
240
252
None

None
None

8
12
13
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28
60
82
157
162
214
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255


Title Page
Determination of the Effect of Varying Amounts of Potash on the Composition,
Yield and Quality of the Crop .............. ............................. 58
Determination of the Effect of Various Potash Carriers on Growth, Yield and
Com position of Crops .................. .........................................................................------------ 58
The Effect of Various Fertilizer Formulas --...........-...-----------.. ---....-------...... 58
Concentrated Fertilizer Studies ....-... -- ... ..........---................ ... 59
Determination of the Effect of Green Manures on the Composition of the Soil .... 59
A Study of "Chlorosis" in Corn Plants and Other Field Crop Plants ........................ 60
Bronzing or Copper Leaf of Citrus ..................-.......... ........------ 60
The Occurrence and Behavior of Less Abundant Elements in Soils ............................ 61
Soil and Fertilizer Studies with Celery ................................... .. 61
Nutrient Salt Concentration in the Soil with Special Reference to the Trace
Elements .......... ---......------------------- --.------------ 62
Investigation of Vitamin C Content of Florida Fruits and Vegetables ........................ 62
Mineral Content of Vegetable Crops ....... ........................--.......... -- 62

The Florida Flower Thrips (Frankliniella cephalica bispinosa Morgan) ................ 64
Root-Knot Investigations ...--.....---..------..-.--------------------- 64
Introduction and Propagation of Beneficial Insects ..........................--....----.. -- ------ 65
The Larger Plant Bugs ...................................................... 65
Bean Jassid Investigations .................-............. ....---............... 66
The Green Citrus Aphid ....................................................... 66
Control of Fruit and Nut Crop Insects-Insects Affecting Pecan Trees .................... 66
Control of Scale-Insects on Woody Ornamentals .........---...----............... -- 67
Insect and Other Animal Pests of Watermelons ....................-......--.. .....-- ... 67
Biology and Control of Field Mice in Watermelon Plantings .............. ....---......... 67
The Onion Thrips (Thrips tabaci Lindin) ............ .... ............... ....... 67
The Gladiolus Thrips (Taeniothrips gladioli M. & S.) .....................................--- 67
Biology and Control of the Florida Aphis .......... .................. .................. 68
The Pepper Weevil (Anthonomus eugenii Cano) ..................................-.........----- 68

The Relation of Growth to Phosphorus, Calcium and Lipin Metabolism as In-
fluenced by the Thym us ....................... .................... ... 70
A Study of Lecithin Synthesis in Hens on a Vitamin A and Lipoid Free Diet ........ 70
A Study of the Hematopoietic Tissues of Rats on a Diet Low in Vitamin A ............ 70
A Study of the Pathologic Changes in Tissues Affected by Deficiency Diseases or
by Toxic Substances....... ............- ... ..--- .-- .. .... ....... -------- 71
An Investigation of Human Dietary Deficiencies in Alachua County, Florida, with
Special Reference to Nutritional Anemia in Relation to Home Grown Foods 71





Department
HORTICULTURE

















PLANT PATHOLOGY


Number Title P
46 Variety Response of Pecans to Different Soil Types, Localities, etc. .......................
47 Cooperative Fertilizer Tests in Pecan Orchards ..........................................................
48 Variety and Stock Tests of Pecan and Walnut Trees ............................................
50 Propagating, Planting and Fertilizing Tests with Tung-oil Trees ...........................
52 Testing of Native and Introduced Shrubs and Ornamentals and Methods for
their Propagation .......................... ...........................................................................
80 Cover Crop Tests in Pecan Orchards .....................................................................
110 Phenological Studies on Truck Crops in Florida ........................................................
111 Fundamental Physiology of Fruit Production .............................................................
165 Relation of Nitrogen Absorption to Food Storage and Growth in Pecans ..............
187 Variety Tests of Minor Fruits and Ornamentals ................... ...................................
189 Study on the Preservation of Citrus Juices and Pulps ......... .........................
190 Cold Storage Studies of Citrus Fruits ........ ........................................................
237 Maturity Studies of Citrus Fruits ................................................................................
238 Studies on the Effect of Zinc and Other Unusual Mineral Supplements on the
Growth of Horticultural Crops .................................................................
266 Spectrographic Studies of the Composition of Tissues and Corresponding Soils
of Normal and Physiologically Diseased Horticultural Crops ..........................
N one Fum igation Research .............................. ......................................................................

19 Downy M ildew of Cucurbits ............................................... ...........................................
126 Investigations Relative to Certain Diseases of Strawberries of Importance in
F lorida ......................................... .............................. ...........................................
130 Studies Relative to Disease Control of White (Irish) Potatoes ................................
143 Investigation and Control of Brown Rot of Potatoes and Closely Related Plants
Caused by Bacterium solanacearum E. F. S. ............................................................
146 Investigations of Seedling, Stalk and Ear Rot Diseases of Corn Caused by
D iplodia sp. ................. ........... ..... ............... ................................................
148 Investigations of Diseases of Ferns and Ornamental Plants .....................................
150 Investigation of and Control of Fusarium Wilt, a Fungous Disease of Water-
melons Caused by Fusarium niveum .................................................................
151 Investigation of and Control of Fungous Diseases of Watermelons ......................
167 A Study of the So-called "Rust" of Asparagus plumosus ..........................................
180 Control of Wilt of Tomato, Fusarium lycopersici Sacc., in Florida ...........................
181 Clitocybe Mushroom Root Rot of Citrus and Other Woody Plants in Florida ........
182 Control of Black Spot (Phoma destructive Plowr.) of Tomatoes in Florida and
in T ransit ................ ..... ........ ...-. ..- ....................... ... ..... ........ ..........


'age
73
74
75
75

76
76
77
78
78
79
79
80
80

81

82
83

85

85
85

86

87
87

87
88
88
89
89
90











Department Ni
PLANT PATHOLOGY
(Continued)









SPECTROGRAPHIC
LABORATORY





FEDERAL-STATE
HORTICULTURAL
PROTECTIVE SERVICE

CITRUS STATION


umber Title P
184 A Study of Strawberry Wilt or Crown Rot --......-.....--. ---------.-------
193 Certain Studies of Decays of Citrus Fruits in Storage ....--------------
196 A Study of the Spraying Requirements Necessary to Control Grape Diseases in
Florida ............---...-----------------------------------
242 Investigations of a Bark Disease of Tahiti Lime Trees .............................................
247 A Study of Sclerotium rolfsii Sacc. in Florida; Its Host Relations and Factors
Influencing Its Pathogenicity ................ ...-----------.........
253 A Study of Rose Diseases in Florida and Their Control ...........................................------
254 Investigations of Fruit Rots of Grapes ............. ......................................-----
259 Collection and Preservation of Specimens of Florida Plants ......................-- ..----------..
264 Virous Diseases of Tomato and Pepper ................-....----.... --------

201 A Study of the Chemical Composition of the Ash of Florida Fruits and Vegetables
with Reference to the More Unusual Constituents .............-----.---------------------
221 A Study of the Chemical Properties of the Glucosides of Citrus Fruits ................
256 The Development of Quantitative Spectrographic Methods for Agricultural Re-
search .................................---- ............----
266 Spectrographic Studies of the Composition of Tissues and Corresponding Soils
of Normal and Physiologically Diseased Horticultural Crops ...................--------.


3
21
24
26
34
35
102
185
233


age
90
91
91
91
92
93
93
94
94


97
97
97

98


No outlined projects; report of progress ....................-------------------- 99


Melanose of Citrus and Its Control .........-......-------- ----------------- 107
Dieback of Citrus ...-..........-............------------------------------ 108
Citrus Scab and Its Control ................------------ --------- -- 110
Citrus Progeny and Bud Selection .--........--... .--------------------- 110
Propagation Experiments with Citrus Plants of Various Kinds ...........----.....................----... 110
Testing of Introduced New Varieties and Hybrids of Citrus and Near Citrus ........ 111
Citrus Variety Tests, Including Rootstocks ....-....-...... ---- ------------ 111
Investigation of Stem-end Rot of Citrus Caused by Phomopsis citri Faw. ................ 113
Control of Purple Scale and Whiteflies with Lime-Sulphur .......................................-- 114






Department
EVERGLADES
STATION


























NORTH FLORIDA
STATION


Number
85
86
87

88
89
90
168

169

170

171
172
195
202
203
204
205
206
207
208
209
210
211
212

219
249

25
33
136
160
191


Title Page
Fruit and Forest Tree Trials and Other Introductory Plantings ........................... 118
Soil Fertility Investigations Under Field and Greenhouse Conditions .................... 120
Field and Laboratory Studies upon Insect Pests of South Florida with Particular
Reference to Methods of Control ........................... ................ 123
Soils Investigations ................................. ...... ....... ... .......... .......... ................................ 124
Water Control Investigations ............................................. .............. 125
Studies in Crop Rotation ......................................... ......... ........................... ... 127
Studies upon the Role of Special Elements in Plant Development upon the Peat
and Muck Soils of the Everglades .................................. ........ .....- 127
Studies upon the Prevalence and Control of the Sugarcane Moth Borer, Diatraea
saccharalis Fab., in South Florida ...................................... 128
Studies of the Prevalence and Control of Rodents under Field and Village Con-
ditions ....... ............................ ............. ........ ........ ................... ........... 129
Cane Breeding Experiments ........................................... ........ 129
General Physiological Phases of Sugarcane Investigations .......................................... 129
Pasture Investigations on the Peat and Muck Soils of the Everglades ........................ 129
Agronomic Studies with Sugarcane ..................................................... .................... 130
Forage Crop Investigations ..................................... ..... 131
Grain Crop Investigations ....... ...... . ............................................ .....................- 132
Seed Storage Investigations ...................... ...................... ............... 133
Fiber Crop Investigations ................................................................................. .... 133
Cover Crop Investigations .. ......................................... ...................... 133
Agronomic Studies upon the Growth of Syrup and Forage Canes in Florida ............ 133
The Seed and Soil-Borne Diseases of Vegetable Crops .................................... 134
The Leaf Blights of Vegetable Crops ................................... ........................... .....-- 135
Physiological Phases of Plant Nutrition ........ ........... ................... ................. 137
Relation of the Organic Composition of Agricultural Plants to the Progress of
Vegetative Development and the Occurrence of Maturity ............... ........ ....... 138
Beef and Dual-Purpose Cattle Investigations ..........................................-.... 138
Nematode Investigations ........................................ ...... ..................... ....... 140

Field and Laboratory Studies of Tobacco Diseases ................................ ........ 141
Developing Strains of Cigar-Wrapper Tobacco Resistant to Blackshank .............. 143
Comparisons of Various Grazing Crops with Dry Lot Feeding for Pork Production 143
Fattening Fall Pigs for Spring Market ............................... ........................ ............. 143
Some Factors Affecting the Germination of Florida Shade Tobacco Seeds and
Early Growth of Seedlings .................................... ... ................... ................ 144










Department
NORTH FLORIDA
STATION
(Continued)




SUBTROPICAL
STATION









WEST CENTRAL
FLORIDA STATION


Number
200
219
241

257
260
261

None
None
None
None
None
None
None
None
None
None
None

None
None
None
224
225
226
227

228

229
None
None


Title Page
Cotton Nutrition Studies ................................-....- ..........----.......... ...............--- .....--.--- 144
Beef and Dual-Purpose Cattle Investigations --........... --.............--.................-----...... 144
Efficiency of the Trench Silo for Preservation of Forage Crops as Measured by
Chemical Means and by Utilization of the Nutrients by Cattle ........................ 145
Columbia Sheep Performance Investigation ........................-------.......------ ..-146
Grain Crop Investigations ................................. ...... .............. ... .. 146
Forage Crop Investigations ...................... ....... ...... .......... ........ .... 147
R eforestation ....-............... ................... .......... ....... ....... ........................ ..... 148
Studies of M inor Fruits and Ornamentals ................ ..... .... ................. ..... ................. 149
A avocado Culture Studies .................................... ........................................................... 149
Citrus Culture Studies .............................. .. ................................................................. 150
Tomato Culture Investigations ..-- ----....... -... -------.. -----.. 150
Improvement of Tomatoes Through Selection of New Hybrids .................................... 150
Potato Culture Investigations ................................. ........-- ........ ....................... 151
Varietal Test of M inor Vegetable Crops .................... ................. ....................... 152
Bacterial Soft Rot of Potatoes ............. ............... ................. ....................................... 153
Control of Potato Diseases in Dade County ........ .......-.. ........ .............................. 154
Control of Tomato Diseases by Spraying ..................................................... ............... 154
Dual-Purpose Cattle ................................... ............................... .....---- 155
Pasture Grasses ...................................... .......... ................ .- ... ........... ... ...- ... 156
Forage Crops for Silage ............................................................. ............. ..... .......----- 157
The Use of Peanuts and Peanut Products in Rearing Turkeys .................................... 158
Confinement Versus Range Rearing of Chicks ..... -................ ................................... 159
Importance of Range Rotation in Poultry Production -....-......................................---- 159
Study of Egg Production and Mortality from Pullets Reared Under Confinement
Versus Range Conditions ............................ ................. ..... .--- 160
A Comparative Study of the Value of Milk Solids, Ground Peanut Kernels with
Hulls, Meatmeal and Fishmeal in Fattening Broilers and Fryers .................... 160
All Night Lights Versus No Lights on Single Comb White Leghorn Hens ........-....... 161
Poultry Breeding Investigations -........................................ ....... -................. ...... 161
A Study of Egg Coolers for Farm Use ..... ------......................... ........................ 161






Annual Report, 1936 15

REPORT OF BUSINESS MANAGER
Receipts and expenditures of State funds for the fiscal year ending
June 30, 1936, covering the Main and Branch Stations, were as follows:

Receipts MAIN STATION
1935-36 ................................................................. ............... .. $160,919.20
Expenditures
Salaries ................................................................................$ 79,815.93
Labor .................................................................................... 21,574.20
Stationery and office supplies .------...................................... 963.67
Scientific supplies ............................................................ 2,232.84
F eeds ................................. .................... .................. ........ 3,544.33
Fertilizers ....................................................----. 1,173.23
Sundry supplies ................................................... ..... 2,741.58
Communication service .................................................... 2,531.39
Travel ..................................................................... ........... 7,246.73
Transportation of things ............................................ 1,151.54
Publications, printing ....................................... ......... 7,406.62
Heat, light, power service ................................................ 5,564.38
Contingent expense .-.................................... ........ 1,111.59
Furniture .................................................... 1,979.37
Library ................................................................................ 1,925.33
Scientific equipment .......................... .... ............ 2,690.96
Tools, machinery ........................................................ 6,092.83
Livestock ................................. ...... ........................... 400.00
Buildings and land ............................................................ 4,321.88
Unexpended balance ........ ..-------- ........................----- 6,510.80 $160,919.20


Receipts BANKHEAD-JONES OFFSET
From Main Station, 1935-36 ............................................$ 12,731.30
From Station Incidental funds, 1935-36 ...................... 2,268.70 $ 15,000.00
Expenditures
Salaries ............................................................................. $ 3,400.00
Labor ................................................................................. 5,804.64
Scientific supplies ..----........................................ .--- 589.10
F eeds .......................................................................... ....... 1,975.21
F ertilizers .......................................................................... 631.22
Sundry supplies ............................................................... 881.27
Travel .................................................................................. 1,121.58
Heat, light, power service ..................................... .. 596.98 $ 15,000.00

Receipts CELERY DISEASE INVESTIGATIONS
1935-36 ................ ...... ....- .... ...-. ..... .................... $ 5,250.00
Expenditures
Salaries ............................................ ........ .................... $ 3,555.99
Labor ......................-------........ .-----................-. 806.25
Scientific supplies ... --................................... ........-- 84.64
F fertilizer ............................................................................ 124.80
Sundry supplies ........................................................... 30.97
Communication service ................................................... 69.34
Travel ........................................-.................--. 319.70
Transportation of things ................................................ 14.89
Heat, light, power service ................................................ 85.63
Contingent expense .......................................................... 30.00
Library ................................................................................ 4.26
Scientific equipment .................................................. 4.22
Buildings and land ........................... ............................ 115.48
Unexpended balance ...................... ....... .... ... 3.83 $ 5,250.00







16 Florida Agricultural Experiment Station

CITRUS DISEASE INVESTIGATIONS
Receipts
1935-36 ...................... ................ . ............ .... ....--------------- 3,500.00
Expenditures
Salaries ............................... ....... .. 3,260.00
Travel ............................------------ .... -------------. 55.70
Scientific equipment .....................................-- .. 24.24
Buildings and land ...........-......------------ .-----....--. 150.00
Unexpended balance .................................. ......... 10.06 S 3,500.00


FUMIGATION RESEARCH
Receipts
1935-36 ................................. ............ ... .. ................... 3,062.50
Expenditures
Salaries ...........................................................................$ 2,700.00
Labor ........................------.............................................. 251.38
Scientific supplies .. .................................................... 2.43
Stationery ............. ----........ -------- ---------- 1.00
Sundry supplies ...........--........---.........---------- 23.86
Heat, light, power service ............................................-- 38.31
Scientific equipment .................. ............. .... 26.50
Tools, m achinery ....................................----.. 9.25
Unexpended balance .................................... ........... 9.77 $ 3,062.50


GRAPE PEST INVESTIGATIONS
Receipts
1935-36 ........................... ............................----- -----.--..$ 3,500.00
Expenditures
Salaries .............................. ............ ....... ....$ 2,520.00
Labor .....................----------------- ----------- 212.80
Scientific supplies .....-------------- .. ------........ 10.36
F ertilizer ................................................................... 91.68
Sundry supplies ................................. ---. --. ------ 19.70
Communication service .............................--- ...- ......... 29.76
Travel ......................... ----------.... ------------ 342.55
Heat, light, power service .............................................. 40.49
Contingent expense ........................---..---...... 30.80
Scientific equipment .............................-------- -- 117.41
Tools, machinery ...-.......----......-- ----. -------. 71.68
Buildings ............. --------------------------- 7.26
Unexpended balance ............................... ............... 5.51 $ 3,500.00


PECAN INSECT INVESTIGATIONS
Receipts
1935-36 ................ ....................... .......... --. -- ........ $ 4,150.00
Expenditures
Salaries .........................- ............... ....... ..$ 1,700.00
Labor .........................------------------ 494.25
Sundry supplies ......................- -.............--... 36.37
Travel ................................................................. 68.50
Heat, light, power service ...................................-- 11.80
Unexpended balance ........................................ ...... 1,839.08 $ 4,150.00







Annual Report, 1936


POTATO DISEASE INVESTIGATIONS
Receipts
1935-36 ....... ............................ ...... ......... $
Expenditures
Salaries ........................................ ... ...................$ 3,573.33
Labor ........................................................... 50.86
Scientific supplies ..:............. .. ............................... 26.86
Sundry supplies .................................................... ...... 24.90
Communication service ............................................... 52.31
Transportation of things ...................................... 2.95
Heat, light, power service ................................... 148.72
Contingent expense ...........- ....................... 72.00
Furniture ................. ............................................................ .98
Tools, machinery ....................... ...................... 40.44
Unexpended balance ....... .......................... ........ 6.65 $


LABORATORY AT HASTINGS
Receipts
1935-36 ........................................................$
Expenditures
Unexpended balance ................. .....................$


STRAWBERRY DISEASE INVESTIGATIONS


Receipts
1935-36 ..............................................................
Expenditures
Salaries ................................... .... .............................. $
L abor ........................... ........ ...........................
Stationery ................. ................... ........... ... ........
Scientific supplies ................................ ..........
Fertilizer ..................................
Sundry supplies .......................... .............
Communication service ............. ......................
Travel .................................. ......................... .........
Transportation of things ...........................................
Heat, light, power service ........................................
Contingent expense ....................................................
Scientific equipment ............................... .....................
Tools, m achinery ............................................................
B buildings ................................ .. .. .......... ........ .. ......
Unexpended balance .......................................................


-$ 6,300.00


5,160.00
553.00
8.77
57.58
1.65
117.34
8.25
164.05
8.78
102.17
3.96
35.94
9.95
3.13
65.43


TOMATO DISEASE INVESTIGATIONS
Receipts
1935-36 ................................................ ............... .. ......................... $
Expenditures
Salaries .........................................................................$ 2,160.00
Labor ............... .................................................................... 197.11
Feed .................................................................................... 70.65
Sundry supplies ......................... ........... ........ 38.54
Communication service .................................................. 64.20
Travel ....................................................................... 96.20
Heat, light, power service ..............................-.............. 106.68
Contingent expense ............................................. 1.00
Furniture .......................................................................... 6.25
Tools, machinery ........................................................ 47.87
Unexpended balance ........................................ ....... 111.50 $


$ 6,300.00


2,900.00










2,900.00


4,000.00










4,000.00



5,250.00

5,250.00







Florida Agricultural Experiment Station


CITRUS EXPERIMENT STATION
Receipts
1935-36 ..................-............... ...... ..... ......... .. ...........$ 46,451.00


Expenditures
Salaries .............................................................................$ 14,076.83
Labor .................................................................................. 6,376.56
Stationery .......................................................................... 47.64
Scientific supplies ........-...................................... 2,169.77
Feed ........................................................ 752.63
Fertilizer ............................................................................ 1,554.29
Sundry supplies ............................. ------........... 597.25
Communication service ................................... ...... 156.16
Travel ................................................................................. 927.90
Transportation of things ..............-..-....---.. .................. 70.33
Heat, light, power service ............................ ..... ... 670.97
Contingent expense ........................ .... ........ ... 1,392.75
Furniture ......................................................................... 822.33
Library ................................................................................ 33.09
Scientific equipment ..........................-.......---. .... 1,549.66
Tools, machinery ................... ............................... 3,915.02
Buildings ............................... ........................................ 2,047.89
Unexpended balance ........................................................ 9,289.93


$ 46,451.00


EVERGLADES EXPERIMENT STATION


Receipts
Continuing appropriation, yearly ................................$
1935-36 .......................................................

Expenditures
Salaries ................ .............................................................$
Labor ...................... ........................... .................
Stationery .............. ....................... ...... ............
Scientific supplies .............................. ...............
F eeds .............................................................. ....---
F ertilizer ............................................................................
Sundry supplies .----........................................ ...-....
Communication service ...............................................
Travel ...................................-....--- ..........--- ..........-------
Transportation of things ................................................
Publications ................................---.-. ..............
Heat, light, power service ............................................
Contingent expense .......................................................
Furniture --------------------------------------------------- ------------------------
Furniture ........................................
Library .................... ..... ..... ...........
Scientific equipment .............. ............. .........
Tools, machinery ............................................
Buildings .............--....--....... --------....
Unexpended balance ........................... ..... ...


5,000.00
45,339.00


$ 50,339.00


24,387.93
14,805.61
99.34
418.67
1,111.84
132.96
1,020.02
270.83
449.46
53.42
9.95
2,641.79
120.10
91.29
297.83
190.31
1,293.00
2,321.69
622.96 $ 50,339.00






Annual Report, 1936 19



NORTH FLORIDA EXPERIMENT STATION
Receipts
1935-36 .......................... .. .... ............. .........$ 25,968.00

Expenditures
Salaries ..............................................................................$ 13,075.17
Labor .................................................................................... 5,420.77
Stationery .......................................................................... 18.57
Scientific supplies .............................................................. 157.49
Feeds ..... -........ ... .. ................. ............................. 1,749.98
Fertilizer ......................................................................... 1,448.20
Sundry supplies ................................................................ 1,676.38
Communication service ................................................... 125.14
Travel ............................................................... .............. 216.86
Transportation of things .....................--- ---..---................. 32.21
Heat, light, power service .................................... 793.35
Contingent expense .......................................................... 94.12
Furniture ...................................................... 9.25
Library ............ ........ ... ............... ..... 56.16
Scientific equipment .......................................................... 1.05
Tools, m achinery .............................................................. 398.68
Buildings ............................................................................ 617.44
Unexpended balance ........................................ .......... 77.18 $ 25,968.00





SUBTROPICAL EXPERIMENT STATION
Receipts
1935-36 ..................................... ................... ...............$ 10,579.00
Expenditures
Salaries ......................................... $ 6,420.00
Labor .............................................. 2,454.25
Stationery ...................................... ......... .... 14.81
Scientific supplies ........................................................... 77.39
F eed .................................................................................. 8.00
Fertilizers ................................................................... 413.38
Sundry supplies ................................................... 233.80
Communication service ................................................. 112.16
Travel .................................................................................. 300.05
Transportation of things .................................... 35.55
Publications .--.---. ------- -------------- 10.50
Heat, light, power service .............................................. 324.67
Contingent expense ............................... ........... 29.50
Furniture ............................................... ........ .. 55.69
Library ........................... .............. 5.20
Tools, m machinery .............................................................. 65.12
Buildings ......................... ...................... 7.00
Unexpended balance ....................................................... 11.93 $ 10,579.00






Florida Agricultural Experiment Station


WATERMELON DISEASE INVESTIGATIONS
Receipts
1935-36 ...................................................... $
Expenditures
Salaries ................ ......... ...........................--$ 5,340.00
Labor ......... ... ......... ....... .......... ............. 766.73
Scientific supplies ............................-------- .... 31.46
Sundry supplies .......................---------. 84.58
Communication service ............................ ............ 64.18
Travel ...........................-- ....... ----------- 264.55
Heat, light, power service .....................-...----.............. 167.13
Contingent expense ............................---------- ----....... 18.10
Furniture .........................-- ...--.---....---- -.... ................. 6.50
Library .................................. ...........-....................... 14.50
Scientific equipment ........-- ............. --- --------- 55.00
Tools, machinery ......................-....----- ------ --- 66.45
Buildings ....................................... 26.25
Unexpended balance ............................---. .---- .. 94.57 $


7,000.00













7,000.00


SPECIAL-DAIRY HUSBANDRY
Receipts
1935-36 .-------.--. --..--.--. ---------.----- $ 15,540.00
Expenditures
Salaries ...........-......---- -----.---------$ 2,300.00
Labor .................................................................................. 1,137.40
Scientific supplies ..................... ..... 57.12
Feeds ................................. 487.73
Sundry supplies ............................................................... 442.82
Travel ............................. --. ..... .. 103.90
Library ...-. :................... --........-... 37.74
Scientific equipment ....................-.- 431.72
Tools, machinery .........................-- .--....- 64.65
Buildings ............................................................................ 2,113.96
Unexpended balance ...............................---- ..... 8,362.96 $ 15,540.00


SPECIAL-POULTRY HUSBANDRY
Receipts
1935-36 ........................-........... ...... $ 12,500.00
Expenditures
Salaries .........................---------- $ 4,875.00
Labor .............................-.... 1,375.61
Stationery ................................. 2.65
Scientific supplies .................................. 292.09
Feeds .................................... 463.45
Sundry supplies ............................ 57.57
Travel .....................................----------------------.............................................-----------234.00
Transportation of things ........................-----... 4.91
Contingent expense ...........................------. 14.55
Furniture ............................. .------.. 4.00
Library .............................................................................. 4.34
Scientific equipment ..........................------- 256.49
Tools, machinery ........................-------.... 59.50
Livestock ................................ 272.40
Buildings ....................... 999.92
Unexpended balance ...................................................--------..... 3,583.52 $ 12,500.00






Annual Report, 1936 21

FROST FORECASTING SERVICE
Receipts
1935-36 ........................................ ...................$ 10,000.00
Expenditures
Salaries ........................................ .............. ..............$ 1,395.00
Labor ....................................................................... ... 6.00
Stationery ......................................................... ...... 44.60
Sundry supplies ...................--.............. ........ 45.71
Communication service ........... ............................... 591.19
Travel ................................................................................. 2,566.69
Transportation of things ..................--- ....... .-----.. 10.00
Publications ...................................... 33.35
Contingent -xpense .......................... ....... ...... 13.90
Furniture ....................................... ....... ..1,508.37
Scientific equipment ................... ......... ... 26.40
Buildings ............................ ....... 803.55
Unexpended balance ............. .......................... 2,955.24 $ 10,000.00


HATCH AND ADAMS FUNDS
Receipts and expenditures of Hatch and Adams funds for the fiscal
year ending June 30, 1936 were as follows:
Receipts
Hatch fund ................................... ............................... $ 15,000.00
Adam s fund ....................................................................... 15,000.00 $ 30,000.00
Expenditures
Salaries ............... .. ......................... ....................-------........ $ 30,000.00







Florida Agricultural Experiment Station


EDITORIAL AND MAILING DEPARTMENT

The diffusion of useful and practical knowledge gained through research
by this Station's workers continued on an enlarged scale during the year.
With the constant accumulation of additional information having vital
value to Florida's general farmers, fruit growers, truck growers, and
animal husbandrymen, dissemination of this knowledge through bulletins,
news stories, farm paper articles, radio talks and miscellaneous methods
has grown apace. The information is largely utilized by both rural and
urban residents of Florida.

LARGE NUMBER BULLETINS PRINTED AND DISTRIBUTED
Seventeen new bulletins, second largest number coming within one
fiscal year, were printed during the year, bringing the grand total of
bulletins issued by the Station since its establishment in 1887 to 298.
Five of the new bulletins were technical and 12 popular in nature. They
ranged in size from 16 to 64 pages and in edition from 5,000 to 15,000
copies. They totalled 580 pages, and 125,500 copies were printed.
Between 75,000 and 100,000 copies of Station bulletins were distributed
from the Mailing Rooms during the year, the great majority of these
on special request from Florida residents. Florida bulletins experience
considerable demand from people out of the state, but in so far as possible
these requests are held to a minimum. Only lists maintained for distri-
bution of new bulletins are those of libraries and scientific workers through-
out the country. To all others, bulletins are sent only on request.
Following is a list of bulletins issued during the year, together with
titles, number of pages, and number of copies of each.
Bul. Title Pages Edition
282 Lime-Sulfur Spraying for the Combined Control of Pur-
ple Scale and Rust Mites ..............................-............... 40 10,000
283 Composition of Miscellaneous Tropical and Sub-Tropical
Florida Fruits ......................................-.............-.....--. 20 7,500
284 The Etiology of Fowl Paralysis, Leukemia and Allied
Conditions in Animals I and II ........................................ 60 5,000
285 Cotton Varieties for Florida ................................................ 24 6,000
286 Cutting Experiments with Bahia Grass Grown in Ly-
sim eters .................................. ........ .... ....................... 36 5,000
287 Economic Study of Absentee Ownership of Citrus Prop-
erties in Florida ............................................-.................. 32 10,000
288 A Wilt-Resistant Watermelon for Florida ...................... 16 10,000
289 Pasture Value of Different Grasses Alone and in Mixture 28 6,000
290 A Study of Some Trace Elements in Fertilizer Materials 16 5,000
291 Relative Susceptibility of Some Annual Ornamentals to
Root-knot ......................................................................... ... 16 15,000
292 The Use of Zinc Sulphate Under Corn and Other Field
Crops ................................... ............. .......-...................-... 52 8,000
293 Etiology of Fowl Paralysis, Leukemia and Allied Con-
ditions in Animals III and IV ........................................ 24 5,000
294 Spraying Experiments for the Control of Certain Grape
Diseases .............................................................. 16 6,000
295 Potato Growing in Florida ................................................... 48 10,000
296 Blight-a Non-Parasitic Disease of Citrus Trees ............ 64 5,000
297 A Cover Crop Program for Florida Pecan Orchards ....... 44 8,000
298 The Reaction of Zine Sulfate with the Soil ........................ 44 5,000






Annual Report, 1936


SUMMARY OF BULLETINS

282. Lime-Sulfur Spraying for the Combined Control of Purple Scale
and Rust Mites. (W. L. Thompson, pp. 40, figs. 0.) Reports results of
experiments during 1933 and 1934 in spraying with lime-sulfur for the
control of various citrus insects, including purple scale, rust mites and
whitefly. Discusses spray injury and seasons for spraying.
283. Composition of Miscellaneous Tropical and Sub-Tropical Florida
Fruits. (A. L. Stahl, pp. 20, figs. 0.) Chemical and physical character-
istics of various tropical and sub-tropical fruits grown in Florida, includ-
ing mangoes, acid citrus fruits, the Japanese persimmon, and others,
are listed as a result of numerous analyses.
284. The Etiology of Fowl Paralysis, Leukemia and Allied Condi-
tions in Animals I and II. (M. W. Emmel, pp. 60, figs. 0.) In this series,
of which this is the first bulletin, Dr. Emmel sets out to show that these
troubles are caused by bacteria of the typhoid and para-typhoid group.
Section I includes an introduction, with the history and a bacterial theory
of these diseases; Section II reports on the intravenous injection of sus-
pensions of Salmonella aertrycke in the chicken. Technical.
285. Cotton Varieties for Florida. (W. A. Carver, pp. 24, figs. 2.)
Recommends varieties of cotton, both wilt-resistant and wilt-susceptible,
for Florida conditions, based on experiments over a period of years.
286. Cutting Experiments with Bahia Grass Grown in Lysimeters.
(W. A. Leukel and R. M. Barnette, pp. 36, figs. 0.) Experimental results
in growth behavior, composition of top growth, stolons and roots, and
the leaching of water and plant nutrients are reported. Application to
practice is suggested. Technical.
287. Economic Study of Absentee Ownership of Citrus Properties in
Florida. (H. W. Hawthorne and J. E. Turlington, pp. 32, figs. 1.) Reports
methods of caring for groves and harvesting, packing and marketing fruit,
size of properties and age of trees, cash costs and receipts, yield, price,
and other pertinent information.
288. A Wilt-Resistant Watermelon for Florida. (M. N. Walker, pp.
16, figs. 8.) Describes a new variety of watermelon, developed at the Lees-
burg Laboratory of the Experiment Station, and names this variety the
Leesburg. The variety resists wilt and is of satisfactory shipping and
eating qualities.
289. Pasture Value of Different Grasses Alone and in Mixture. (Geo.
E. Ritchey and W. W. Henley, pp. 28, figs. 9.) Reports pasture experi-
ments through the five years 1929-1933, giving results with the grasses
and with the steers grazed on them.
290. A Study of Some Trace Elements in Fertilizer Materials. (L. W.
Gaddum and L. H. Rogers, pp. 16, figs. 0.) Reports analyses, with par-
ticular reference to trace elements of a large number of fertilizers and
materials. Analyses were made with a Littrow spectrograph; for zinc
determinations, however, the authors determined that a quartz Cornu
type spectrograph was necessary. Technical.
291. Relative Susceptibility of Some Annual Ornamentals to Root-Knot.
(C. C. Goff, pp. 16, figs. 2.) Lists annual ornamentals in order of sus-
ceptibility to root-knot nematodes, as determined by four years of experi-
mentation on infested soils.
292. The Use of Zinc Sulphate Under Corn and Other Field Crops.
(R. M. Barnette, J. P. Camp, J. D. Warner and 0. E. Gall, pp. 52, figs. 14.)
White bud, which has plagued corn over a considerable area in northern







Florida Agricultural Experiment Station


Florida for years, was controlled by applications of zinc sulphate. Defi-
ciency diseases of peanuts, oats, velvet beans, cowpeas, Pearl millet, and
other field crops were remedied in the same manner.
293. The Etiology of Fowl Paralysis, Leukemia and Allied Conditions
in Animals III and IV. (M. W. Emmel, pp. 24, figs. 0.) Section III
reports studies of the intestinal flora of chickens affected with enteritis
associated with intestinal parasitism; Section IV discusses the pathologic
manifestations of the causal micro-organisms in the fowl. Technical.
294. Spraying Experiments for the Control of Certain Grape Diseases.
(Kenneth W. Loucks, pp. 16, figs. 1.) Experiments were conducted in
an effort to determine a spraying schedule that would enable the grape
grower to produce a crop of marketable fruit. Bordeaux was the most
effective agent used. Number of applications necessary varies with sea-
sonal conditions.
295. Potato Growing in Florida. (W. M. Fifield, pp. 48, figs. 13.)
Soils, varieties, seed, land preparation, fertilizers, planting, cultivation,
spraying, harvesting, grading and packing, and marketing are discussed
as related particularly to Dade County and the Hastings area.
296. Blight-a Non-Parasitic Disease of Citrus Trees. (Arthur S.
Rhoads, pp. 64, figs. 20.) Gives final results of a long series of tests with
citrus troubled with blight, and advances belief that blight is due to
layer of rock underlying the soil.
297. A Cover Crop Program for Florida Pecan Orchards. (G. H.
Blackmon and R. M. Barnette, pp. 44, figs. 20.) Well fertilized pecan
orchards growing cover crops both summer and winter make best growth
and yield.
298. The Reaction of Zinc Sulfate with the Soil. (H. W. Jones, 0. E.
Gall and R. M. Barnette, pp. 44, figs. 6.) Stimulating and toxic actions
of zinc compounds had been previously studied, but definite knowledge of
reactions of zinc sulfate with the soil was lacking. This bulletin reports
results of experiments which determined this reaction, and supplemental
factors affecting reaction.

PRESS BULLETINS
Twenty-nine press bulletins, 20 new and 9 reprint, were issued during the
year. Each (except the Bulletin List, which was four pages in length
and restricted to 2,500 in number) contained two pages of succinct and
timely information for Florida growers and farmers. Total number of
copies printed in each case was 3,000. Following is a list of press bulletins
issued during the year.
No. Title Author
478 Borax as a Fertilizer for Celery ....... E. R. Purvis and R. W. Ruprecht
479 The Pepper Weevil in Florida ........................................ J. R. Watson
480 The Glovel Tomato ............ W. S. Porte, H. S. Wolfe and W. M. Fifield
481 Bark Disease of Tahiti Lime and Perrine Lemon ............ W. B. Tisdale
482 The Control of Root-Knot in Seedbeds ............................ J. R. Watson
483 Plants Susceptible and Resistant to Root-Knot ................ J. R. Watson
484 Rose Canker .............................. .............. William B. Shippy
485 Black Spot of Roses ............................................... William B. Shippy
486 Powdery Mildew of Roses .................................... William B. Shippy
487 Manganese Sulphate Sprays for Vegetables Crops ........ G. R. Townsend
488 Zinc Sulphate Sprays for Vegetables Crops ................. G. R. Townsend
489 Comparative Productiveness of Missionary Strawberry Plants
from Arkansas and Maryland ................ ........................ A. N. Brooks







Annual Report, 1936 25

290 A New Squash from Africa ............................................. Geo. E. Ritchey
491 Damping-Off of Plant Seedlings ................................ George F. Weber
492 Downy Mildew of Cucurbits ........................................ George F. Weber
493 Rhizoctonia on Beans ........ .............. .....----........ .. George F. W eber
494 Seed Disinfection .................... ............ ............ George F. W eber
495 Black Rot of Cabbage .................................................... George F. W eber
496 Soils for Azaleas ................................ R. M. Barnette and Harold Mowry
497 Calcium in Dairy Rations ............... R. B. Becker and P. T. Dix Arnold
Bulletin List
327 How to Poison Ants (reprint) .......................................... J. R. Watson
438 Pear Blight and Its Control (reprint) ........................ George F. Weber
439 Fig Rust and Its Control (reprint) ............................ George F. Weber
446 Mosaic Diseases of Vegetable Plants (reprint) ........ George F. Weber
450 Yellowing of Centipede Grass and Its Control (reprint) .... O. C. Bryan
452 Preparation of Lime-Sulphur Sprays (reprint) ........ George F. Weber
453 Methods for Preparing Bordeaux Mixture (reprint).... George F. Weber
475 Colds and Roup in Poultry (reprint) .................................. M. W. Emmel

LITTLE STORIES OF FLORIDA AGRICULTURE
This series of envelope stuffers, one each month describing some im-
portant accomplishment of the Station's research workers and showing
how it has helped the state's agricultural industries, was continued through-
out the year. Five thousand copies of each were printed, and most of
them were distributed in current correspondence. Each consisted of four
pages 3% x 614 inches. They met with cordial reception throughout the
state.
Numbers distributed during the fiscal year included 11-22, inclusive.
Titles, consecutively, were: Paving the Way to Farm Progress (general
review of research values); Cows Now Fatten on Citrus Refuse; Plant
Food with June Day Rarity (trace elements); "Men and Beasts Eat from
One Row" (of improved sugarcane); Rural Research "Goes to Grass";
Science Wins Bout with Melon Wilt; Orange Juice, Too, When Milk Comes;
Fertilizers Taken Out of Hash Class (through spectrographic analysis);
"Trouble Shooters" for Florida Farms (answers to correspondence); Sav-
ing Baby Lives in Tropical Storm (by personal service and advice); Cutting
Dog's Tail Behind His Ears (pest eradication); and Making State Again
Blossom as a Rose (through research with ornamentals).

SERVICE TO NEWS AND FARM PRESS
Information from the Experiment Station continued to be demanded
by newspapers, particularly in Florida and to a certain extent over the
nation. Through the Associated Press a number of stories were given
national distribution, and were widely printed. Material was supplied
to Florida dailies through the AP and by special stories sent direct. The
weeklies continued to receive the clipsheet of the Agricultural Extension
Service which contained from one to six Experiment Station items each
week.
Two daily papers carried departments of questions and answers on
farming subjects each Sunday, copy for these being supplied by this office
and based largely on actual questions received and answered by Station
workers.
Farm papers continued to give excellent cooperation in using all pos-
sible information from the Station. The Editors themselves wrote 10
articles about Station work for four Florida papers, amounting to 314







Florida Agricultural Experiment Station


column inches, but this was only a small proportion of material used
from here. Vast numbers of articles by members of the staff, particularly
copies of radio talks, were forwarded through this office and direct by
authors to all farm journals and house organs in Florida, and voluminous
use was made of them.
The Editors also wrote five articles, amounting to 90 column inches,
for one Southern farm journal, and three articles for as many national
journals for a total of 51 column inches.

FARM RADIO TALKS
Staff members of the Experiment Station spoke frequently over the
radio, particularly during the Florida Farm Hour over WRUF, the Univer-
sity and State radio station in Gainesville. The Farm Hour is directed
by the Extension Service. Records show that 190 talks were made by
Station staff members during the year.
Farm flashes are supplied daily to five other Florida radio stations
by the Extension Service, and 37 of these talks by Station workers were
converted into flashes for these other stations.

SCIENTIFIC AND POPULAR ARTICLES IN JOURNALS
Numerous articles, reporting work at this Station and establishing an
enviable reputation for the organization in the scientific field, were printed
by scientific journals throughout the United States. In many cases, also,
staff workers prepared and sent popular articles to journals for publica-
tion. In only a small proportion of cases were either the scientific or
popular articles edited in this office. Following is a list of these articles
printed during the fiscal year.
Additional observations on the toxicity of Crotalaria spectabilis for swine.
M. W. Emmel, D. A. Sanders and W. W. Henley, Jour. Amer. Vet.
Med. Assn. Vol. 40. 1935.
A general summary of insect conditions in Florida. J. R. Watson. Citrus
Industry, March 1936.
A lesson in feeds. R. B. Becker. Jour. Dairy Sci. Vol. 19. 1936.
A resume of insect conditions in Florida in 1935-and some pointers for
1936. J. R. Watson. Citrus Industry. Feb. 1936.
A quantitative method for the determination of minute amounts of copper
in biological materials. L. L. Rusoff and L. W. Gaddum. Proc. Fla.
Acad. Sci. 1936.
A reproductive schedule and diary and its use. P. T. Dix Arnold and
W. M. Neal. Proc. Assn. Sou. Agr. Workers. 1936.
Breeding: a factor in fowl paralysis. M. W. Emmel. Poultry Item.
Jan. 1936.
Chemical analysis and the law of definite proportions. L. W. Gaddum.
Proc. Fla. Acad. Sci. 1936.
Clean-up measures against rust mites on citrus. J. R. Watson. Citrus
Industry. June, 1936.
Control of aphids on citrus. J. R. Watson. Citrus Industry. May 1936.
Controlling household ants. J. R. Watson. Sou. Agriculturist. June 1936.
Decomposition of organic matter in Norfolk sand: The effect upon soil
and drainage water. C. E. Bell. Jour. Amer. Soc. Agron. Vol. 27.
Nov. 1935.
Distinguishing characters of Florida zephyranthes. H. H. Hume. Proc.
Amer. Amaryllis Soc. 1935.
Duplications in zephyranthes. H. H. Hume. Bul. Torrey Bot. Club.
Vol. 62. Oct. 1935.






Annual Report, 1936


Effect of frequent cutting of Bahia grass on the utilization of nitrogen
and other nutrient elements. W. A. Leukel. Proc. Amer. Soc. Agron.
1935.
Effects and after-effects of hurricanes on sub-tropical fruits. H. S. Wolfe.
Proc. Fla. State Hort. Soc. 1936.
Effects of fertilizer on yield of pecan trees. G. H. Blackmon. Proc. South-
eastern Pecan Grs'. Assn. 1936.
Effects of cover crops on the yield and quality of pecan nuts. G. H. Black-
mon. Proc. Natl. Pecan Assn. 1935.
Essential plant foods. C. E. Bell. Citrus Industry. Aug. 1935.
Experimental work on tomato and potato problems. W. M. Fifield. Miami
Herald. Mar. 17, 1936.
Experiments with-zinc sulphate for the correction of "white bud" of corn.
R. M. Barnette and J. P. Camp. Agr. News Letter, E. I. DuPont de
Nemours Co., Vol. 3, Nov. 1935.
Florida range cattle problems. A. L. Shealy. Proc. Amer. Soc. Animal
Production Nov. 1935.
Fowl paralysis and leukemia. M. W. Emmel. U. S. Butter and Poultry
Magazine, 42:83. 1935.
Glovel tomato attracts widespread attention. W. M. Fifield. Homestead
Leader-Enterprise, Aug. 20, 1935.
Ground snapped corn. R. B. Becker. Proc. Assn. Sou. Agr. Workers. 1936.
Hemocytoblastosis and its relation to the development of fowl paralysis
and fowl leukemia. M. W. Emmel. Jour. Amer. Vet. Med. Assn.
41:45. 1936.
How to fight household insects. J. R. Watson. Sou. Agriculturist. April,
1936.
Influence of preceding dry period and mineral supplement on lactation.
P. T. Dix Arnold and R. B. Becker. Jour. Dairy Sci. Vol. 19. 1936.
Insect control saves much money for Florida. A. N. Tissot. Citrus In-
dustry, Feb. 1936.
Kinky tail in cattle. M. W. Emmel and Bradford Knapp, Jr., Jour. Amer.
Vet. Med. Assn. Vol. 41. 1936.
Legumes in pecan orchards. Proc. Assn. Sou. Agr. Workers. 1936.
Many fruit factors face experimenters. H. S. Wolfe. Miami Herald,
Mar. 17, 1936.
Mechanical help for field sampling of sugar cane. F. D. Stevens. Proc.
Int. Soc. Sugar Cane Tech., 5th Congress, Brisbane. 1935.
Pecans need fertilizers. G. H. Blackmon. Progressive Farmer, Nov. 1935.
Phosphorus content and buffer capacity of plant sap as related to the
physiological effect of phosphorus fertilizers in fibrous low-moor peat.
J. R. Neller. Jour. Agr. Research. Vol. 51. Aug. 1935.
Poultry husbandry at the University of Florida. H. H. Hume. Florida
Poultryman, Sept. 1935.
Premiums paid for high quality in cauliflower. J. D. Hartman and F. S.
Jamison. Proc. Amer. Soc. for Hort. Sci. Vol. 33. 1936.
Present status of lime bark diseases. W. B. Tisdale. Proc. Fla. State
Hort. Soc. 1936.
Problems peculiar to Dade County agriculture studied. H. S. Wolfe.
Miami Herald, Mar. 17, 1936.
Progress in zinc sulphate studies. A. F. Camp and Walter Reuther. Citrus
Industry, March 1936.
Relation of foliage to tree maintenance and fruit production. B. R. Fudge.
Proc. Fla. State Hort. Soc. 1936.
Report on fertilizer experiments with pecans in Florida. G. H. Blackmon.
Proc. Natl. Pecan Assn. 1935.







Florida Agricultural Experiment Station


Results of fertilizer experiments. R. W. Ruprecht. Fico News. Oct. 1935.
Results of some further studies of the determination of zinc. L. H. Rogers
and O. E. Gall. Proc. Fla. Acad. Sci. 1936.
Resume of truck crop season. F. S. Jamison. Florida Grower, March 1936.
Soil reaction and azalea growth. R. M. Barnette and Harold Mowry. Soil
Sci. Vol. 41, Jan. 1936.
Soil temperature studies on Florida cigar-wrapper tobacco. R. R. Kincaid
and L. O. Gratz. Jour. Agr. Res. 51:5. Sept. 1935.
Some new aspects of gummosis and psorosis of citrus trees in Florida.
A. S. Rhoads. Proc. Fla. State Hort. Soc. 1936.
Spectrographic microdetermination of zinc. L. H. Rogers. Ind. and Eng.
Chem. Anal. Ed. Vol. 7, Nov. 1935.
Tariff changes as they affect Florida. C. V. Noble. Florida Grower.
May, 1936.
Tests indicate change in potato fertilizers. W. M. Fifield. Homestead
Leader-Enterprise, Oct. 18, 1935.
The advantages of Florida in the control of poultry diseases. M. W.
Emmel. Florida Poultryman 2:8. 1936.
The control of purple scale and rust mite with lime-sulphur solution. W. L.
Thompson. Citrus Industry. Nov. 1935.
The correlation of classification and distribution in zephyranthes. H. H.
Hume. Natl. Hort. Magazine, July, 1935.
The Curtis Gavel. G. H. Blackmon. Proc. Southeastern Pecan Grs'. Assn.
1936.
The digestible nutrients of Napier grass and Crotalaria intermedia silages,
Natal grass hay, and the dried refuse of grapefruit and orange can-
neries. W. M. Neal, R. B. Becker and P. T. Dix Arnold. Jour. Agr.
Res. Vol. 51. 1935.
The effect of an organic mulch on soil temperature and moisture. Harold
Mowry and H. W. Jones. Citrus Industry. Jan. 1936.
The effect of season of the year and advancing lactation upon milk yield
of Jersey cows. P. T. Dix Arnold and R. B. Becker. Jour. Dairy Res.
Vol. 18, Sept. 1935.
The influence of varying amounts of water-soluble phosphorus on different
soil types on the response of cultivated crops. O. C. Bryan and W. M.
Neal. Jour. Agr. Res. Vol. 52, Mar. 1936.
The introduction and propagation of the Chinese ladybeetle in citrus groves.
J. R. Watson. Proc. Fla. State Hort. Soc. 1936.
The isolation and some properties of an alkaloid from Crotalaria spectabilis
Roth. W. M. Neal, L. L. Rusoff and C. F. Ahmann. Jour. Amer. Chem.
Soc. Vol. 51. 1935.
The new fertilizer plan. R. W. Ruprecht. Citrus Industry. Aug. 1935.
The relation of cover crops to insects on citrus. J. R. Watson. Citrus
Industry, June, 1936.
The toxicity of Glottidium vesicarum (Jacq.) Harper seeds for the fowl.
M. W. Emmel. Jour. Amer. Vet. Med. Assn. 40:13. 1935.
The use of fertilizer on Florida soils. R. W. Ruprecht. Citrus Industry.
March 1936.
The use of rabbits in determining the palatability or toxicity of forage.
Geo. E. Ritchey. Jour. Amer. Soc. Agron. 28:6. June 1936.
The yellowing of citrus leaves. A. F. Camp and Walter Reuther. Proc.
Fla. State Hort. Soc. 1936.
Trends in citrus plantings. C. V. Noble. Lakeland Ledger and Star Tele-
gram, May 17, 1936.
Value of truck crops close to citrus. C. V. Noble. Florida Grower, Nov.
1935.







Annual Report, 1936


LIBRARY

Insofar as statistics may show the activities of the library the following
table represents the year's work:
Volumes sent to bindery ................................................ 377
Volumes received by purchase and exchange ........ 133 /
Total number bound volumes in Library .................... 13,035
Pamphlets, continuations, etc., received .................... 9,170
Catalog cards prepared, typed and filed
in dictionary card catalog .................................. 6,737
Books and journals lent to local staff ........................ 5,000
Books lent to branch stations ....................................... 536
Books borrowed from other libraries ........................ 81
Books acquired and assembled material from the bindery during the
year have brought the total number of bound volumes on the shelves to
13,035. The Library received 9,170 pamphlets and continuations, which
were 395 more than for the year previous. A large portion of this material
requires nearly as much care in preparing it for the shelves as would
an equal number of books. This is especially true of many of the new
agricultural publications published by both the federal government and
state institutions at the present time. While 6,737 catalog cards were
prepared, typed and filed in the catalog, the cataloging, because of in-
sufficient help, has not kept up with the material that requires it. The
use of material both within the Library and borrowed has been unprece-
dented. The local staff and faculty borrowed 5,000 volumes, and 536
loans were made to the staff workers at branch stations.
For some time the demand for keeping the Library open during the
evening has been growing. Believing that by doing this during the week
from 7 until 10 o'clock would not only help those persons who needed
the extra hours for study but would also equalize the use of the Library
through a greater number of hours and somewhat reduce the congestion
during the day, beginning October 6, 1935, these evening hours were
inaugurated and continued through May 1936. During this period a
check made of reserve material only requested by students showed that
7,546 books were used.
Since some of the most valuable literature from the standpoint of
scientific research is that published by scientists in other countries, a
project was begun for the abstracting in English of certain of these
foreign publications. As a result 145 abstracts of articles were made.
In addition to the regular duties, the Library has assisted many persons
throughout the state in locating publications and securing data pertaining
to agricultural subjects.







Florida Agricultural Experiment Station


AGRICULTURAL ECONOMICS

For the first three months of the fiscal year regular projected work
was greatly curtailed to make way for emergency project 262 which was
being conducted in cooperation with the Agricultural Adjustment Adminis-
tration and the Bureau of Agricultural Economics. This emergency work
culminated in the issuance of a preliminary report late in September 1935.
Since that date some additional data have been obtained in connection
with this project, but the attempt has been made to concentrate upon
the regular projects of the Department.

AGRICULTURAL SURVEY OF SOME 500 FARMS IN THE GENERAL
FARMING REGION OF NORTHWEST FLORIDA
Purnell Project 73 C. V. Noble and Bruce McKinley
Work on this economic survey of representative farms in Jackson
County, Florida, was started 10 years ago and has been in progress,
intermittently, since that time. The purpose has been not to base
interpretations upon data for a single year, but to obtain similar data
for several years.
Data are now in hand for the years 1925, 1928 and 1934. At the present
time field work is in progress to obtain similar data for the year 1935
and it is the purpose to proceed with the interpretation of this four-
year sample as soon as the field work has been completed.

FARMERS' COOPERATIVE ASSOCIATIONS IN FLORIDA
Purnell Project 154 H. G. Hamilton and C. V. Noble
This project has been inactive during the fiscal year because of emer-
gency work and centering of effort on the other projects carried.

COST OF PRODUCTION AND GROVE ORGANIZATION STUDIES
OF FLORIDA CITRUS
Purnell Project 186 C. V. Noble, Zach Savage
and Bruce McKinley
Work on this project has been in progress for almost four years. After
the close of each fiscal year, summary sheets have been prepared and
returned to each cooperator. These summaries include costs, returns and
other pertinent data by kinds of fruit, ripening season of fruit, and age
of trees. A copy of the summary sheet for midseason oranges 12 to 14
years of age is here shown as Table 1. Sheets for 1934-35 show compari-
sons of various items for three years.
Cold weather of the fiscal year 1934-35 did considerable damage to
some of the fruit and affected very materially the results. Some grove
accounts had no fruit that was marketed. Trees in some groves were
damaged by the cold weather.
At the end of the 1934-35 accounting year, accounts for the year were
closed on 33 groves with a total of 1,173 acres of citrus. At the same time
accounts were opened for the 1935-36 accounting year on 34 groves with
a total of 1,183 acres of citrus.







Annual Report, 1936 31

TABLE 1.-COSTS AND RETURNS FOR MID-SEASON ORANGES,
12 TO 14 YEARS OF AGE.

Average Average Average
All All All Your
Groves Groves Groves Grove

Season ..................... .......................... 1932-33 1933-34 1934-35 1934-35
Number of accounts ............------ ........... 4 9 12
Age of grove (years) ............--....-.... 12to14 12to14 12to14
Acres per grove ...................................... 21.67 11.02 9.31
Trees per acre ...-.................................. 61 65 66
Grove value per acre .............................. $639.95 $651.01 $617.86
Yield in boxes per acre ........................ 138 106 128
Yield in boxes per tree ........................ 2.24 1.63 1.95


Costs per acre:
Labor .................................................... $ 12.36 $ 10.08 $ 10.51
Supervision ........................................ 10.13 10.32 6.39
Power and equipment ........................ 6.19 5.34 4.82
Labor, power and equipment
not separated ...................-............ .15 1.06 1.331
Fertilizer ............................................. 17.24 14.48 20.44
Soil amendments ..........-----.................. .70 .81 1.482
Spray and dust ... -.............................. 2.03 2.30 2.193
Irrigation and drainage .---............... 2.26 1.70 1.664
Taxes .............................-............ 4.79 4.07 6.00
Interest on grove at 7% .................... 44.80 45.57 43.25
All other costs .............................-- .. 2.02 2.41 2.565
Total costs per acre .............................. 102.67 98.14 100.63
Returns per acre ................................... 127.90 54.68 107.316
Profit per acre (- denotes loss) ........ 25.23 -43.46 6.68

Costs per box .......................................... .746 .926 .785
Returns per box ..................................... .929 .516 .837
Profit per box (- denotes loss) ........ .183 -.410 .052

Pounds of fertilizer per acre ................ 1255 1066 1392
Pounds of fertilizer per tree ................ 20.43 16.42 21.19
Pounds of soil amendments per acre 25 133 4087
Pounds of soil amendments per tree .40 2.04 6.21


All averages in the above columns are based upon totals for all groves.
For purposes of comparison of the averages of the specific groves involved
with your individual grove for the season 1934-35, the following notes are
given:
1 Only seven groves had this cost which averaged $6.76 per acre. Part
of spray and dust materials were included in this item on three groves.
2 Only six groves had this cost which averaged $1.72 per acre.
3 Only eleven groves had this cost which averaged $2.20 per acre.
4 Only five groves had this cost which averaged $3.35 per acre.
5 Only nine groves had this cost which averaged $2.87 per acre.
6 Only nine groves had fruit returns which averaged $115.07 per acre for
138 boxes of fruit.
7 Only six groves had soil amendments applied which averaged 474 lbs.
per acre or 7.64 lbs. per tree.







Florida Agricultural Experiment Station


A STUDY OF PRE-COOLING AND OF REFRIGERATION IN TRANSIT
AS AFFECTING COST OF MARKETING, QUALITY
AND PRICE OF CITRUS FRUITS
Purnell Project 235 A. H. Spurlock, Zach Savage
and Bruce McKinley
The first sorting and tabulating of data have been completed in co-
operation with the Farm Credit Administration of Columbia, South Caro-
lina. Also summarization and analysis have been completed for a part
of the study and a manuscript covering the first phase is in preparation.
In the eight markets* studied for the three seasons 1930-31, 1931-32
and 1932-33, sales of all packed fruit from the 31 packinghouses consisted
of 95 percent auction, and 5 percent f.o.b. and brokerage sales. Of
the auction sales 49.7 percent were oranges, 40.6 percent grapefruit, and
9.7 percent tangerines and other mandarin fruit.
Of the five auction markets included, the New York auction received
a larger quantity of citrus than the other four combined. Also a higher
percent of the high grade fruit and a lower percent of low grade fruit
went to New York than to the other auction markets.
In the 1930-31 and 1931-32 seasons, higher prices were usually obtained
in New York than in the other markets for the same grade and variety
of fruit, especially the high grade fruit. In 1932-33 the prices were
usually higher in other markets.
The total cost of marketing citrus at auction in New York decreased
from an average of $1.14 per box in 1930-31 to $1.00 in 1931-32, and to
$.89 in the 1932-33 season. The average total cost in the other auction
markets showed little change during the three seasons, being $1.16 in
1930-31, $1.14 in 1931-32, and $1.15 in 1932-33. Most of the reduction
to New York was due to the increased use of lower cost water trans-
portation.
Lower average prices were received for all kinds of citrus in 1932-33
than in the preceding two seasons. The fall in prices was not offset by
lower marketing costs, even to New York, and net returns to the shipper
were therefore much lower than in the preceding two seasons.

FARM TAXATION
Purnell Project 248 C. V. Noble
This project has been closed out with a mimeographed report issued
December 24, 1935, by the Division of Agricultural Finance, U. S. Bureau
of Agricultural Economics, entitled "Tax Delinquency of Rural Real Estate
in Six Florida Counties, 1928-33". This work was performed cooperatvely
with the Bureau of Agricultural Economics and the Civil Works Adminis-
tration.
To bring out the increasing seriousness of rural real estate tax delin-
quency for the five years beginning in 1928, the following table sum-
marizes the complete data obtained from Gadsden, Jackson, Jefferson,
Orange, Santa Rosa, and Suwannee counties.
The tax delinquent area in these counties in 1928 represented 17 per-
cent of the total area in farms. In 1932 the tax delinquent area had
increased to 62 percent of the total farm area. This situation has been
much improved during the past two or three years by the better economic
conditions in rural areas and by the passage of the Homestead Exemption
Law of 1935.

*New York, Chicago, Detroit, Pittsburgh, Cincinnati, Minneapolis, Kansas City, and
New Orleans.






Annual Report, 1936


TABLE 2.-TOTAL DELINQUENCY OF RURAL REAL-ESTATE TAXES, SIX-
COUNTY TOTAL, BY YEAR OF LEVY, 1928-32.

Year of Properties involved Amount
levy Assessed of taxes
Number Acres valuation delinquent
1,000 dollars Dollars
1928 1,522 172,963 681 42,059
1929 2,004 194,627 674 48,928
1930 3,422 316,562 1,358 82,642
1931 3,076 334,267 1,332 66,395
1932 7,274 635,030 2,763 109,144


A STUDY OF ADJUSTMENTS IN FARMING BY REGIONS AND TYPE-
OF FARMING AREAS, FROM THE STANDPOINT OF
AGRICULTURAL ADJUSTMENT AND PLANNING,
INCLUDING SOIL CONSERVATION
Purnell Project 262 C. V. Noble and Bruce McKinley
(in cooperation with Federal Project No. 1100, A.A.A. and B.A.E.)
Most of the work on other projects was set aside to make way for the
completion of as much information as possible on this emergency project
before October 1, 1935. A preliminary report, entitled "Types of Farming
in Florida" was prepared and submitted to the Bureau of Agricultural
Economics late in September 1935. The principal conclusions arrived at
and recommendations made from the standpoint of agricultural adjustment
and planning for the outstanding type-of-farming areas in Florida were:
Citrus Areas. 1. The best farms in the citrus area are as a rule larger
than the average farm.
2. The best farms have much higher fruit yields than the average.
3. The best farms receive higher prices than the average.
4. Livestock is not important in the area and the best farms have a
smaller percent of receipts from livestock than the average.
5. Many groves are sub-marginal not only from the standpoint of soil,
but also from the standpoint of freeze risks. The elimination of these
groves as well as some method for keeping such sub-marginal areas free
from future citrus plantings should be carefully considered in any plans
for the reduction of Florida citrus fruits.
6. Costs of production of citrus per acre have been greatly reduced in
recent years.
7. Too many varieties are being planted with insufficient volume to
establish themselves on the market, thus causing confusion in trade
channels.
Specialized Trucking Areas. Briefly summarizing for the specialized
truck farming areas in Florida the following appear to be the main factors
for successful operations:
1. In general, those farmers having a larger volume of business are
making higher labor incomes. In seasons of low prices, the advantage of
size was not so outstanding as in more profitable seasons, unless, in addi-
tion to the larger size, there were better yields obtained and higher prices
received.
2. Higher than average crop yields were the rule on the profitable
farms.






Florida Agricultural Experiment Station


3. The most profitable farms usually received a unit price for their
product above the average for all farms. This higher price reflected the
higher quality product usually attending higher yields, as well as better
marketing ability of the operators.
4. There was no indication that a greater diversification of crops in
these special trucking areas was advantageous. On the other hand, the
best quarter of the farms in each area seemed to diversify less than all
farms. Livestock, other than work stock, do not appear to have a place
on specialized truck farms.
General Farming Areas. Summarizing the general farming type area
as a whole it would seem that the specific recommendations that can be
made, based upon what the best farmers in this area are doing, would be:
1. Larger farming businesses of the same general character as those
already found in each specific locality.
2. More emphasis placed upon soil fertility, better seed and better
cultural practices to obtain higher crop yields of a better grade of product.
3. There are indications that livestock enterprises, especially hogs and
beef cattle, should assume a more prominent place in this type of farm-
ing, particularly as a safeguard against seasons of ruinous crop prices.
This would necessitate more emphasis being placed upon the improvement
of pastures and the use of more crops in the farming plan for grazing
purposes. It is also increasingly important that more emphasis be placed
upon improved breeds of livestock, since the danger of fever tick infesta-
tion has now been removed.
Specialized Dairy Farms. The three outstanding factors on the most
successful dairy farms were:
1. Larger businesses as measured by number of dairy cows.
2. Higher milk production per cow.
3. Higher price per gallon for milk.
Specialized Poultry Farms. The outstanding factors for success on
poultry farms were:
1. Larger businesses as measured by number of laying hens.
2. Higher yearly egg production per hen.
3. Higher winter egg production per hen.
4. Higher price per dozen for eggs.
5. Lower mortality or death rate in the laying flock.
There was no indication in the poultry study that flocks were becom-
ing too large, but many examples showed inefficiencies of small flocks.
All conclusions and recommendations were based upon summarized
data that were incorporated in the report, such summaries being derived
from farm management studies made in the respective type-of-farming
areas.
A farm management study was made in the Manatee County Trucking
Area after the preliminary report was issued. This study has not been
completely summarized at this date.

ABSENTEE OWNERSHIP OF CITRUS PROPERTIES IN FLORIDA
The Teaching Division of the Department of Agricultural Economics,
in cooperation with the Federal Bureau of Agricultural Economics, made
a study of absentee ownership of citrus properties in Florida. The man-
uscript covering this study was revised and published as Station Bulletin
287 in December 1935. The study is based upon data secured from 477
absentee owners of Florida citrus groves and most of the data related
to the six-season period 1924-25 to 1929-30, inclusive. A large majority
of the groves are located in Polk and Lake counties, but 20 other citrus






Annual Report, 1936 35

counties are represented by one or more groves. Some of the findings
in this study were:
1. Cost to these absentee owners for planting and caring for their
groves through the fifth year averaged $418 per acre. This included price
paid for land.
2. Data for 60 groves with trees in the fourth year revealed that not
a single grove had receipts that equaled its costs, and 44 of these groves
had no receipts. Only 2 of 77 groves in the fifth year had receipts equal
to their costs, and only 9 of 98 groves in the sixth year were paying
their way. It was not until groves had reached the eleventh year that
one-half or more of them were paying their way.
3. The importance of fruit yield per tree or per acre for a given age
of grove was clearly brought out in the comparative net receipts per acre.

FLORIDA TRUCK CROP COMPETITION
The weekly summary of car-lot shipments of the leading Florida truck
crops, together with the competitive shipments from other states and
from importing countries for the 1934-35 season, was compiled and mimeo-
graphed. This is done each year to supplement Florida Bulletin 224 and
keep it up to date.







Florida Agricultural Experiment Station


AGRONOMY

The year's experimental work in agronomy has covered a wide variety
of soils and field crop investigations and has included active coopera-
tion with the United States Department of Agriculture through the Forage
Crops Office on forage problems, the Office of Fiber Crops and Diseases
on Sea Island cotton production, and the Cereal Office on selection and
breeding of rust-resistant oats. Certain phases of pasture research were
carried cooperatively with Foremost Properties, Inc.
The new varieties of oats from South America and Australia continue
to show high resistance to crown rust which so seriously interferes with
the growing of oats in Florida. Work on selection of strains carrying
earliness, good yielding ability and rust resistance is under way, and cross-
ing and recurrent back-crossing with subsequent selection to produce a
desirable type is also being done.
Breeding work with peanuts and field and sweet corn continues to
show very promising results and some foundation stocks of seed corn
have been distributed to selected cooperative corn breeders for further
selection by the grower.
Pasture research work has involved various fertilizer treatments and
their effect on yield and composition, methods of sampling pastures to
obtain comparable yields of herbage, comparison of burned and unburned
native pastures, the effect of land preparation previous to seeding on
establishing and maintaining pastures, and the botanical composition of
native pastures burned and unburned and changes in pasture flora under
the two conditions.
Crop variety, rotation and fertilizer experiments were continued and
yielded results of importance in the matter of economical crop production.
The use of zinc sulfate for preventing chlorosis or "white bud" of corn
and poor growth of certain other crops continues to give good results.
The residual effect of zinc and sources of zinc on crop production are now
being investigated.
New sugarcanes bred at the Everglades Experiment Station are being
selected for their resistance to root-knot, mosaic and other diseases, and
their ability to produce forage in abundance and syrup of good quality
and quantity. All new sugarcanes are being compared to such well known
kinds as Cayana, C. P. 807, and others. The composition of sugarcane at
various growth stages and rate and time of planting are also being
studied.
Much imported new pasture and forage crop material has been under
observation in the forage crop garden, and many native plants, some of
which may develop into good forage crops, have been collected and placed
under culture.
PLANT BREEDING-PEANUTS
State Project 20 F. H. Hull and W. A. Carver
Pedigreed selection within hybrid strains was continued. High yield,
disease and insect resistance, and dormancy or rest period in both market
and hogging off types of peanut are being sought. A good filling Jumbo
as well as a hay type are other objectives.
The breeding block for 1936 contains: (1) 209 older hybrid selections,
(2) 494 third generation families from crosses of Dixie Giant by Spanish
and Rasteiro by older hybrids, (3) 11 second generation families involving
the same parentage as above and in addition older hybrids intercrossed,







Annual Report, 1936 37

and Jumbo crossed to older hybrids, and (4) 32 first generation plants
of Pearl (Spanish) by Dixie Giant, four of Dixie Giant by Jumbo, two of
Pearl by Rasteiro and seven of Pearl by older hybrids. Sixty-seven addi-
tional crosses were made of Dixie Giant, Rasteiro, Nambyquarae, and Pearl
by several older hybrids, Dixie Giant by Pearl, and Rasteiro by Pearl.
Nine older hybrid strains along with several popular strains of both
Spanish and Runner varieties were in a variety test in 1935 for the purpose
of checking the yield of the hybrids against established varieties. Some
of the hybrids showed up well; however, such tests to give reliable results
must be conducted for several years.
To secure better evaluation of relative yields an extensive spacing test
with Spanish, Florida Runner and an intermediate hybrid is being con-
ducted.
PASTURE EXPERIMENTS
Hatch Project 27 W. E. Stokes, G. E. Ritchey
W. A. Leukel
The project is a broad one involving several phases of pasture research.

I. Comparison in Grazing Tests of the Pasture Value of Different
Grasses Alone and in Mixture
This phase of the pasture work at Gainesville has been completed and
the results published in Station Bulletin 289.

II. The Influence of Various Fertilizers on the Yield of Pasture Grasses
This phase of the work with pastures has been in operation since 1930;
therefore, six years' results are available. Seventy-six plots involving
21 different fertilizer treatments are concerned. Fertilizer formulas vary
from those carrying single elements to reasonably high percentages of
the three elements commonly used in fertilizers.
No significant increase in yield was obtained from the use of phos-
phate or potash either alone or in combination. Nitrogen gave decided
yield increases. Lime gave no noticeable increase in yield in connection
with any fertilizers.
The experiment is being continued as the sod, which was composed
largely of Bahia grass at the start, has since changed over largely to
centipede grass.
III. Comparison of Native and Improved Pastures; Comparison of
Burned and Unburned Native Pastures for Both Nine and Twelve
Months' Grazing and a Comparison of Methods of Land Prepara-
tion Previous to Seeding Improved Pastures.
(Animal Husbandry Department, State Forest Service and Fore-
most Properties, cooperating)
Improved pastures continue to give more beef (live weight) per acre
than do native pastures regardless of whether or not the native pastures
are burned. Burned native pastures gave more beef per acre than un-
burned native pastures, in both nine and 12 months' grazing tests.
Good seedbed preparation continues to be superior to poor prepara-
tion of the seedbed previous to planting.
A forage plant survey of native pasture areas used in this experi-
ment has shown the predominating grasses to be of the wiregrass, Aristida
sp., broomsedge, Andropogon sp., and Indian or wild oat, Sorghastrum sp.,
groups.







Florida Agricultural Experiment Station


III-A. Effect of Burning on Growth and Relative Composition of Range
Grasses
Range grasses burned and unburned, both grazed and ungrazed, have
been analyzed in the laboratory. Grass samples were taken monthly.
Where the grass was burned over in January there was a tendency for
the resulting growth to be low in carbohydrates and fibrous material and
high in protein, and this relation persisted through April. Samples of
grass from the unburned areas were lower in percentage of protein and
higher in percentage of carbohydrates and fibrous material than grass
from the burned areas. It appears that burning at intervals may be de-
sirable to keep native range grasses vegetative and thus high in per-
centage of protein and minerals.
IV. Pasture Plant Adaptation Tests
Sixteen different prospective pasture plants have been planted in
what is termed a grass "cafeteria" for cows. Observations on the palata-
bility of these grasses, as indicated by preference of the cattle and be-
havior of the grasses under grazing, will be made.

THE VALUE OF CENTIPEDE GRASS PASTURES AS AFFECTED BY
SOIL CHARACTERISTICS AND OTHER FACTORS
Special Project 27-A
(This is a project carried jointly by the Florida Experiment Station,
the Georgia Coastal Plain Experiment Station at Tifton, Georgia, and the
Bureau of Plant Industry, United States Department of Agriculture.)
The object is to find out why cattle do not thrive on centipede grass
pasture at Tifton, Georgia, whereas on a like pasture at Gainesville, Florida,
cattle make very satisfactory gains.
Samples of the grass and the soil of the centipede pasture areas at
both Tifton and Gainesville have been collected for spectrographic and
other analyses. These samples have been taken at several times during
the growing season.

CROP ROTATION STUDIES WITH CORN, COTTON, CROTALARIA
AND AUSTRIAN PEAS
Hatch Project 55 W. E. Stokes, J. P. Camp
and G. E. Ritchey
This experiment, begun in 1930, involves cotton and corn in a two-
year rotation with and without summer and winter legumes compared to
continuous cotton and corn. As heretofore, both cotton and corn yielded
better in rotation than when grown year after year on the same land.
Cotton has responded markedly to the rotation, but the corn response
has been slight. Winter legume growth on the soil type concerned was
poor and succeeding crop yields were not materially increased, whereas
summer legume yields were good and succeeding crop yields were increased.
During the 1935 season one-half of each plot in this experiment was
treated with zinc sulfate (89%) at the rate of 24 pounds per acre in the
drill row previous to planting. Cotton and corn yields in the rotation
and continuous series were increased from the use of zinc. Zinc seemed
more effective on cotton and corn when grown year after year on the
same land than on these crops when grown in a two-year rotation.






Annual Report, 1936


II. Corn and Crotalaria
Triplicated plots of Crotalaria intermedia, C. spectabilis and C. striata
and natural vegetation are cropped every other year to corn, allowing
the crotalaria to reseed each year. One year's corn yields have been
obtained.
Beginning with the season of 1935 the experiment was extended to
include duplicated plots receiving the same treatment on another field,
thus allowing a greater replication.
III. Corn and Peanuts Rotating with Crotalaria and with
Native Cover Crops
This phase of crop rotation studies has been conducted since 1933.
Corn and peanuts grown on the same land each year show less satis-
factory yields than corn and peanuts rotating alternate years with cro-
talaria or with corn and peanuts rotating alternate and every third year
with native cover crops.
As reported previously no fertilizer nor special elements are used in
connection with this rotation and white bud of corn has been rather
prevalent. This season, white bud has been less in evidence than here-
tofore. However, as in previous years, the most white bud occurred on
corn of the continuous corn and peanut plots.

VARIETY TEST WORK WITH FIELD CROPS
Hatch Project 56 W. E. Stokes, G. E. Ritchey
and J. P. Camp
Sugarcane Variety Test
The 70 sugarcanes selected out of 1,100 kinds in 1934 were further
reduced by rigid selection in 1935 on the basis of yield, freedom from
root-knot, mosaic and other diseases, and apparently good syrup and
forage characters. These selections were planted in replicated plots of
four rows each 17.5 feet long and involve 256 plots representing some 30
kinds of sugarcane. Cayana, C. P. 807, CO 290, Tekcha and Uba, a group
of well-known sugarcanes, are used as checks. Some appear very promis-
ing as syrup and forage types. Further selection and propagation will
be continued.
Double-line planting compared to single-line planting of stalks in the
row resulted in slightly better than six tons of sugarcane per acre increase
with C. P. 807. This would indicate a double-line planting of stalks in
the row could be used to advantage.
Oat Variety Test
The following varieties of oats were in the variety test in 1935-36:
Fulghum, Appler, Goff's Black Hull, Nortex, Bond, Country Common and
Alba. Early maturing varieties such as Fulghum and Goff's Black Hull
yielded best. The others being later in maturing suffered from dry weather
with resultant low yields. The Bond variety from Australia and Country
Common and Alba from South America, as well as the previously tested
Victoria, also from South America, are of particular interest to Florida
because these oats are immune or highly resistant to crown rust. Selec-
tions from these oats for earliness and good yield and retention of rust-
resistance qualities or the use of these oats in breeding operations to give
an early maturing, high yielding rust-resistant oat are now under way.
Fulghum, Appler and Goff's Black Hull varieties for the present appear
best for the Gainesville territory. (Refer to the North Florida Station
report for oat varieties suited to that area.)







Florida Agricultural Experiment Station


Corn and Peanut Variety Tests
See Projects 105 and 20.
Lespedesa sericea Variety Test
One-third acre each of Lespedeza sericea F. C. No. 04730, 17291 and
19284 have been planted for study as to their possible forage value. The
influence of different fertilizer treatments, particularly rates of phos-
phate, on each strain is under test.
Rice Variety Test
Plots of Patna rice C. I. No. 7689 and a commercial strain of Pearl
rice have been planted to determine adaptability and value for grazing or
other purposes. The influence of fertilizers is also being studied.

COVER CROP AND GREEN MANURE STUDIES IN CITRUS GROVES
State Project 83 W. E. Stokes, J. H. Jefferies
and R. M. Barnette
Work on this project has been discontinued.

GREEN MANURE STUDIES
Hatch Project 98 W. A. Leukel and G. E. Ritchey
This project is in cooperation with the Department of Chemistry and
Soils' Project No. 96 and involves field and phytometer trials with the
three most promising Crotalarias, namely, C. striata, C. spectabilis and
C. intermedia, using corn as the indicator crop in the field trials and
oats and Sudan grass as the indicator crops in the phytometer trials. Field
tests are in duplicate and phytometer trials are sufficiently replicated for
accuracy. The purpose is to get information as to the comparative value
of green manure crops in crop production and to learn something of the
effect of green manure crops on the fertility and productivity of the soil.
The experiment has not progressed sufficiently to give definite information.

IMPROVEMENT OF CORN BY SELECTION AND BREEDING
Purnell Project 105 F. H. Hull and W. A. Carver
Field Corn
Corn variety tests have shown Whatley Prolific to be a 20% to 30%
better yielder than the Florida corns, but it is not as weevil-resistant and,
as a result, is not generally used. The problem then is to breed field
corns of both yellow and white varieties which are high yielding, weevil-
resistant and prolific and results seem more certain through hybridization
than through straight selection.
Breeding has continued by methods noted in previous reports: (1)
Selection of inbred lines for use in double crosses; (2) Combining pre-
potent inbred lines with established varieties to give foundation stocks
for mass selection by farmer breeders and at branch experiment stations.
Selected inbreds have been tested in top crosses on Whatley Prolific
and Erck Yellow Flint for northern and southern Florida, respectively.
A summary of the records on 500 Whatley top crosses for the past three
years shows an average gain of 13 percent in yield. Five top crosses
yielded 59 percent more than Whatley. Another five top crosses which
were generally good averaged 38 percent gain in yield, 40 percent reduction
in weevily ears, 75 percent gain in flintiness, 10 percent gain in soundness,
9 percent reduction in lodging and 6 percent gain in prolificacy. Double







Annual Report, 1936


crosses of some of the better lines should yield 30 to 50 percent more
than common varieties grown in Florida and be equal or better in weevil
resistance and other characters.
Thirty inbred lines were tested in top crosses on Erck Yellow Flint
at Gainesville, Belle Glade and Weirsdale. The average yield was 19
percent greater than Whatley Prolific at Gainesville and 22 percent
greater than Erck Yellow Flint at Weirsdale on muck land. A poor
crop at Belle Glade prevented taking yield records, though some top crosses
looked promising.
Five hundred inbred lines developed on mineral soil at Gainesville
were grown at Belle Glade on sawgrass muck. Some of the inbred lines
may be valuable in south Florida on both muck and mineral soils.
The 1936 breeding plot at Gainesville contains 200 inbred lines and
their crosses with Whatley Prolific, 100 crosses with Erck Yellow Flint
and about 200 each of single and double crosses. At Quincy there are
150 Whatley crosses, 50 Erck crosses and 50 double crosses. At Belle
Glade there are 200 inbred lines and 100 Erck crosses. At the Erck
muck land farm near Weirsdale there are 100 Erck Yellow Flint crosses.
A foundation stock of corn prepared for mass selection breeding in
northern Florida and composed of Whatley Prolific and prepotent inbred
lines was distributed to nine additional farmer breeders, making 29 who
have been thus supplied. In the variety tests at Gainesville and Quincy
this foundation stock has shown up well and without selection yields more
than any native variety. It is probably weevil resistant enough for gen-
eral use and because of its hybrid nature and selected ancestry, selection
on it for yield, weevil resistance and prolificacy should be more effective
than with common corn. The stock is being grown by the North Florida
Station in 1936 in two isolated five-acre plots, one of which is planted
to white seed and the other to yellow seed selected in 1935. Mass selection
in the field will be practiced in both plots.
A foundation stock is being prepared for southern Florida using 75
percent Erck Yellow Flint ancestry and 25 percent of nine inbred lines
whose top crosses on Erck averaged 34 percent gain over Whatley yield
at Gainesville and 37 percent gain over Erck yield on muck land near
Weirsdale where Erck originated. This stock will be distributed to farmer
breeders in 1937. It is now being grown in a three-acre isolated plot
by the Everglades Experiment Station, in five-acre plots by Mr. Geo.
Erck at Weirsdale and Mr. E. W. Dedman of McIntosh. Mass selection
of seed will be made in these plots.
Variety tests have been continued, a mimeographed circular summarizing
results at Gainesville, Quincy and Belle Glade, was issued in December,
1935, and distributed to county agents, seedsmen and others.

Sweet Corn
Sweet strains of the common roasting ear varieties have been obtained
by recurrent backcrossing, as previously reported, and grown in compara-
tive tests with the parent varieties. New sweet varieties from other
experiment stations also were tested. The sweet strains are slightly
smaller and less vigorous than the dent strains but their greatest fault
is poor table quality which is not much better than that of the dent strains.
The trouble is very largely toughness; they are not nearly as tender
as established sweet corns. None of them except Sweet Hickory King
can be released until after further selection for tenderness.
Extensive selection for tenderness was practiced on Sweet Snowflake in
1935 and the results checked in 1936. It is likely that a satisfactory
strain of Sweet Snowflake will be obtained very soon.







Florida Agricultural Experiment Station


A very small early type of sweet corn, obtained from Northern sources,
has been crossed with Tuxpan, the largest and latest field corn available.
The hybrid was crossed back to the high quality strain to intensify quality.
Some selections from the first cross and the backcross are quite satis-
factory in quality and it appears that a few of them may also be satis-
factory in size and vigor.
Records on tests of sweet and roasting ear varieties were made avail-
able in a mimeographed circular in December 1935, and a similar report
will be made in 1936.

CROP ADAPTATION STUDIES
Hatch Project 107 W. E. Stokes and G. E. Ritchey
The crop nursery for study of new crop material of all kinds and
particularly plants likely to be valuable for forage and pasture purposes
has been maintained and greatly enlarged by a collection of native plant
material. About 700 plantings, 300 of which are natives, have been under
observation during the year. Several imported and native plants show
promise and some are being multiplied for further trials.
Seed of the "African Squash", Cucurbita moschata, under test here
four years, was distributed this spring to about 1,000 growers. This
squash is described in Press Bulletin 490.
Adapted strains of Napier grass, Pennisetum purpureum, resistant to
"ring spot" caused by the organism Helminthosporium ocellum, have been
found and planting material is being increased.
From over 200 kinds of pigeon peas, Cajanus indicus, under observa-
tion, two strains, hybrid No. 2 and S. P. I. No. 70957, have been selected
on the basis of earliness, good seeding habits and other desirable char-
acters. Seed is being increased for release.

FERTILIZATION OF PASTURE AND FORAGE GRASSES
Hatch Project 120 W. A. Leukel and J. P. Camp
Most of the work on this project has been completed and reported
on in Bulletin 269.
Fertilization of Napier Grass
Substitution of commercial fertilizers for sewage effluent for the fer-
tilization of Napier grass over a period of years did not result in similar
residual effects as reported in Bulletin 215.
Effects of Various Rates of Nitrogen Fertilization from Different
Sources of Nitrogen on Pasture Grasses
Observations of heavy applications of nitrogen on Bahia grass using
sodium nitrate, ammonium sulfate and cyanamid showed interesting results.
Each fertilizer was applied at rates of 500 and 1,000 pounds of nitrogen
per acre in nine monthly aliquots during the growing season. When
applied during the drier part of the season the greatest burning effects
were noted from the use of sodium nitrate. Cyanamid showed some effects
of burning on the blade tips of the grass as a result of the material
adhering to leaves wet with dew. Little or no burning was noted from
ammonium sulfate. Very marked increase in top growth production
resulted from each treatment.
In this work the effort is to determine: (1) to what extent can grasses
be fertilized with nitrogen before detrimental effects are noted, (2) the
effect of too rapid growth or large production of top growth on stoloni-






Annual Report, 1936


ferous grasses, and (3) the effect on composition by too rapid growth of
grasses through nitrogen fertilization.

DATE OF SEEDING AND PHOSPHATE REQUIREMENTS OF WINTER
LEGUMES AND THEIR EFFECT UPON SUBSEQUENT CROPS
State Project 153 J. D. Warner
This project has been closed. A manuscript covering the results is
in course of preparation.

RATIO OF ORGANIC TO INORGANIC NITROGEN IN MIXED
FERTILIZER FOR COTTON
State Project 159 J. D. Warner
This project has been discontinued.

CORN FERTILIZER EXPERIMENTS
State Project 163 J. D. Warner, W. E. Stokes
and J. P. Camp
This project has been under way since 1930 and has been conducted
both at the experiment stations and cooperatively with farmers and county
agricultural agents over Central and Northwest Florida.
The main objectives are to determine the effect of nitrogen, phosphorus
and potassium singly and in various combinations and amounts on the
yield of corn, the relative efficiency of various sources of nitrogen in corn
production, and the effect of certain less abundant elements, such as zinc,
when used in connection with nitrogen, phosphorus and potassium on the
yield of corn.
Results this year, as in the past, indicate that nitrogen is usually
the most limiting element in corn production. This element has consistently
stimulated yield more than any other in a complete fertilizer. The results,
however, also indicate that on certain soils phosphorus and potassium in
addition to nitrogen are necessary for maximum yields.
Soils of Central Florida do not seem to need the amounts of phos-
phorus and potassium that soils of Northwest Florida do for corn pro-
duction. Inorganic sources of nitrogen seem to be as efficient as the organic
sources on soils of the northwestern area, while organic sources of nitrogen
sometimes give slightly better results on the lighter soils in the central
sections of the state. Prices of the two sources of nitrogen, however, should
largely determine the one to use, since the difference in their relative
efficiency on these lighter soils has been very slight.
There seems to be little or no difference between the various sources
of inorganic nitrogen for corn. In some cases sulfate of ammonia and
leunasalpeter have consistently led, but in other instances this has not
been true. Tests will be continued on the principal soil types.
The use of zinc sulfate in combination with nitrogen, phosphorus and
potassium on corn has not increased the yield of corn except in cases
where the soils normally produce chlorotic "white bud" corn.

A STUDY OF CROTALARIA AS A FORAGE CROP
State Project 174 W. E. Stokes and G. E. Ritchey
This experiment is in cooperation with the Division of Forage Crops
and Diseases, Bureau of Plant Industry, U. S. D. A.
About 18 acres of Crotalaria intermedia were planted in April of 1935.
From previous work it was found that Crotalaria intermedia cut at the






Florida Agricultural Experiment Station


bud stage produced a most palatable silage with a good yield of material.
The 1935 crop for silage was cut in the early bud stage and yielded a
high quality of green succulent, leafy and fine tender stemmed material.
Results of the feeding trials are reported by the Department of Animal
Husbandry.
Rate of Seeding Crotalaria intermedia
One method only of varying the rate of seeding was used in the season
of 1935. The seed was sown the same thickness in each row, but the width
between rows varied as follows: 2 feet apart or 4.2 pounds per acre;
3 feet apart, 3.5 pounds per acre; 3% feet apart, 3 pounds per acre; 4 feet
apart, 2.6 pounds per acre.
Yields did not vary materially, being highest in the 4-foot rows. This
is the reverse of results in 1934. Yields varied from 2.75 tons of green
material per acre on plots with row 2% feet apart to 3.34 tons per acre
from plots sown to 4-foot rows.
Plants sown in 2-foot rows produced finer stems but the lower leaves
dropped badly. Rows spaced 3 feet apart were wide enough for efficient
cultivation, and there was apparently less dropping of leaves. The stems
were a trifle but not significantly coarser. Plants in rows sown 4 feet
apart were coarser stemmed and there was a greater abundance of grasses
and weeds. It appears that the three-foot spacing of rows is most desir-
able when maximum growth is desired with minimum coarseness of stem.

A STUDY OF CHLOROSIS IN CORN PLANTS AND OTHER
FIELD CROP PLANTS
Adams Project 220 R. M. Barnette and J. P. Camp
Refer to report of Department of Chemistry and Soils.

A STUDY OF THE DEVELOPMENT AND DETERIORATION OF ROOTS
IN RELATION TO THE GROWTH OF PASTURE PLANTS
GROWN UNDER DIFFERENT FERTILIZER
AND CUTTING TREATMENTS
Adams Project 243 W. A. Leukel
Work on root growth behavior of pasture plants is still in progress.
The growth cycle of the plant in relation to growth and deterioration of
stolons and roots was given in a previous report; also the difference in
the utilization of nitrogen and other nutrient materials by the roots of
vegetative and more mature plants. Better utilization, especially of nitro-
gen, appears to be based on the greater capacity of vegetative plants
to reduce nitrates by their higher content of reducase, preliminary tests
for reducase indicating such a trend.
Although roots of vegetative grasses have a greater feeding capacity
than those of more mature plants, their root systems are less extensive
and cannot feed from as large a soil area. An effort was made to increase
the feeding area of vegetative plants. Plants were permitted to grow
to a more mature growth condition or up to the reproductive stage at
which period root growth becomes more extensive. When the top growth
of these plants was removed the plants reverted to a vegetative growth
condition. After being reverted to this growth condition the longer or
more extended roots sent out numerous feeders or rootlets. By keeping
the plants vegetative thereafter through frequent cutting, they were able
to feed from a greater soil area and produce more leafage. Such treat-
ment may be of value in the management of pastures, especially just before






Annual Report, 1936 45

the dry season when moisture and nutrients are needed from greater
soil depths.

COMPOSITION FACTORS AFFECTING THE VALUE OF SUGARCANE
FOR FORAGE AND OTHER PURPOSES
State Project 265 W. A. Leukel
Work on this project has just begun and results thus far are not of
sufficient scope to warrant definite statements. Organic analyses were
made on Cayana cane, sorghum, Napier grass and cat-tail millet when
in a growth condition suitable for silage purposes. Variations in per-
centages of sugars, starches, hemicelluloses, total nitrogen and fibrous
residues indicate different values of these plants for forage purposes.
A more intensive study of growth behavior, composition and metabolism
of Cayana sugarcane is under way.

PASTURE STUDIES
Bankhead-Jones Project 267 W. E. Stokes and A. L. Shealy
This project seeks to determine methods and procedure to be followed
in improving, maintaining and managing natural pastures, in establishing
and managing improved pastures and determining their values.
Some land has been acquired on which to begin work and some of the
necessary scientific equipment has been secured. A preliminary plant
survey of one typical natural pasture area has been started.

MISCELLANEOUS
Preliminary Stack Silo Experiments
Surplus sugarcane from the sugarcane variety and line test was again
used in stack silo tests. The cane is run through an ensilage cutter and
stacked on top of the ground and covered with a layer of dirt two feet
thick. Tests thus far indicate that this method of saving ensilage is not
as efficient as when the material is stored in good air-tight concrete, tile,
metal or wood silos and perhaps not as satisfactory as well constructed
trench or pit silos. However, 60 to 70 percent of the silage is saved and
the spoilage can be used for soil enrichment. The method is desirable
where the least cash outlay is desired and where changing location of
feeding operations yearly is necessary.
Comparative Production of Several Silage Crops Grown at Relatively
High Fertility Levels
Napier grass, Cayana sugarcane, sorghum (Texas Seeded Ribbon Cane)
and corn followed by cat-tail millet as the corn is cut are being compared
as silage crops. All are planted on the same soil type (Hernando sandy
loam) and with the exception of cat-tail millet are given the same kinds
and amounts of complete fertilizer, followed by side application of nitrogen
as each crop indicates by its growth that nitrogen is needed. Each crop
does not necessarily get the same total amount of fertilizer. The yields
of green material in tons per acre the past season were Napier grass
44.72, Cayana sugarcane 31.43, sorghum 10.63, corn 6.59, and cat-tail
millet following corn 2.11. The total pounds of nitrogen, phosphorus and
potassium per acre applied to each crop was as follows: Napier grass
112-48-48, Cayana sugarcane 112-48-48, sorghum 80-48-48, corn 78-48-48
and cat-tail millet 60-0-0.






46 Florida Agricultural Experiment Station

Chufa Fertilizer and Spacing Test
Fertilizer and spacing experiments with chufas to determine the effect
of each on yield continue to show but slight increase in yield from the
use of fertilizer.
Close spacing of rows with plants 6 inches apart in the row continues
to give better yields than 12 inch spacing in the row.
Sea Island Cotton
Cooperation has continued with the Office of Cotton and Other Fiber
Crops and Diseases of the U. S. Department of Agriculture in the matter
of growing and maintaining reserve supplies of Sea Island cotton and seed
of the Seabrook strain. Several other strains of Sea Island cotton are
being grown in isolated blocks at the West Central Florida Experiment
Station at Brooksville, and one strain at Gainesville. Seabrook Sea Island
cotton is being grown also at the Watermelon Laboratory at Leesburg.
Cooperative Work with the West Central Florida Experiment Station
Brooksville
Pasture and forage crop planting material has been supplied to the
West Central Florida Experiment Station at Brooksville and members of
the Department have aided in taking notes and records concerning the
pasture and forage crops studies, particularly those having to do with
methods of establishing different pasture grasses.







Annual Report, 1936 47

ANIMAL HUSBANDRY
Research with livestock requires the maintenance of herds of dairy
cattle, beef cattle, and swine and a flock of poultry so that uniform groups
of animals may be obtained for experimental studies. It is important to
know the breeding, feeding and management of all animals used in projects
in animal research. Aside from furnishing experimental animals for
separate projects, valuable herd records regarding breeding efficiency, in-
heritance, feed consumption and mineral requirements are obtained.

THE DAIRY HERD
The purebred Jersey herd at the Main Station supplies animals for use
in comparative feeding trials and nutrition studies. Daily records of this
herd furnish information concerning breeding and management of dairy
cattle in Florida. Complete records are kept of production and reproduc-
tion. Cows discarded from the herd are assigned to further study in
a project on the relation of conformation and anatomy of the dairy cow
to her milk and butterfat production. The past records contributed to
three technical papers during the year.
Nine cows qualified for the Register of Merit as a regular part of
the studies of transmitting ability of sires and dams in the herd. These
are as follows:
Age Milk Test Butterfat
yrs. mos. pounds percent pounds
Florida Wonder Heart 839769 ................ 5 10 8,662 6.06 524.67
Florida Fontaine Marie 839772 ................ 5 2 10,391 5.41 562.41
Florida Reception Heiress 860182 ........ 4 10 7,720 5.40 416.54
Florida Fontaine Beauty 988041 ............ 2 .1 6,206 5.03 312.46
Florida Victor Jewess 988402 ................ 2 0 6,576 5.34 351.45
Florida Victor Fairy 1006290 ................ 2 5 7,897 4.84 381.89
Sybil Eminent Fox Hilda 1038308 .......... 2 6 7,303 5.42 395.62
Sybil Black Lady 1037951 ........................ 2 1 5,079 5.05 256.34*
Jubilant Little Ruby 1038309 ................ 2 3 7,593 5.32 403.75
*Ten-months test.
A detailed study is being made of the transmitting ability of several
sires used in service.

BEEF CATTLE HERD
To determine the real value of grading up herds from native cattle
by using purebred bulls, a herd of native cattle is maintained at the Main
Station. These cows are bred to purebred Hereford bulls. Other breeds
are used in similar studies at the various branch stations. The grade off-
spring, of which several first and second cross calves have been obtained,
are used in various comparisons with native and purebred animals. Birth
weights and rates of growth of these grade calves are recorded. Similar
data have been obtained on native calves. Studies are being made on
winter feeding of the breeding herd, since it is desirable to obtain data
on the most economical way of wintering beef cattle, especially range cattle.

SWINE HERD
A purebred herd of swine is maintained to furnish suitable animals for
projects in feeding and nutrition. Experiments to determine the feeding
value of such crops as corn, peanuts and sweet potatoes alone, or in com-







48 Florida Agricultural Experiment Station

bination, were completed during the past year. The herd is kept on a
series of grazing crops during the entire year in an effort to control internal
parasites. It has been found practical and profitable to control parasites
by this method of feeding and management.

THE NUTRITION LABORATORY
Analytical phases of investigations involving nutrition studies with
animals, and feeds have been conducted in the laboratory. Feeds used in
determining the value of Crotalaria intermedia silage for dairy cows have
been analyzed. Sixty-six samples collected during the past year represdht
the third year's investigation in measuring the efficiency of trench silos
in preservation of the nutrients in silage made from sorghum, sugarcane
and Napier grass. The analyses are involved also in a study of their
comparative feeding value.
A method for the treatment of citrus cannery refuse was developed
whereby the cost of drying the material for livestock feed can be greatly
reduced.
Calcium, magnesium, potassium and sodium nitrates were prepared
with less than one-half part per million of copper. These salts of such
high purity were necessary for cooperative use with the Spectrographic
Laboratory in the development of a method for estimation of such minute
amounts of copper as occur in biological materials with an accuracy ex-
ceeding that of previous methods. This method will be used in conjunction
with mineral nutrition investigations.
A high carotene content was demonstrated in the recently introduced
African squash (Cucurbita moschata).
The investigations in mineral nutrition involve regular hemoglobin,
calcium and phosphorus determination on blood samples from experimental
animals, and preparation of samples for spectrographic examination by
ashing at low temperature.

VETERINARY LABORATORY
Research work on diseases of livestock and poultry during the past
year included studies on hemorrhagic septicemia of cattle and swine, plants
poisonous to livestock, fowl paralysis, leukemia and allied conditions in
the fowl and domestic animals. Many diagnoses of diseases of domestic
animals and poultry have been made for veterinarians and poultrymen.
As a result of rendering this type of service, such diseases as piroplas-
mosis in dogs, paratyphoid infection in turkeys and a deficiency disease
in chickens have been found.

POULTRY INVESTIGATIONS
The PoultryJ)ivision of the Animal Husbandry Department was created
July 1, 193k.
Additional breeds of poultry obtained for research work include Silver
Laced Wyandottes, Single Comb Buff Leghorns and Single Comb White
Minorcas. Other strains of Single Comb White Leghorns, Single Comb
Rhode Island Reds and Single Comb Barred Plymouth Rocks have been
added to the poultry flock.
Projects on methods of brooding chicks and rearing pullets, fattening
broilers, use of artificial lights on pullets and hens, development of an
egg cooler, management of laying birds, and rearing turkeys have been
continued.






Annual Report, 1936 49

An experimental flock of S. C. Rhode Island Reds and S. C. White
Leghorns is being developed to furnish birds for future studies. Experi-
ments with the breeding flocks include studies of egg production, egg
size, livability, broodiness and disease control.
The new 15-acre poultry plant is being developed at the present time
and the poultry laboratory building will be complete in the fall of 1936.
Projects on feeding and management of chicks, laying hens, turkeys,
and breeding have been continued during the past year at the federal West
Central Florida Experiment Station, Brooksville, in cooperation with the
Animal Husbandry Division, Bureau of Animal Industry, U. S. D. A.
The work of these projects is summarized under the report of that Station.
Three projects at the Florida National Egg-Laying Contest at Chipley
have been continued during the past year. One new project was started
on feeding and use of artificial lights.

DEFICIENCIES IN FEEDS USED IN CATTLE RATIONS
Purnell Project 133 R. B. Becker, W. M. Neal, A. L. Shealy
and P. T. Dix Arnold
Deficiencies studied in this project include (1) iron and copper; (2)
calcium; and (3) phosphorus. Investigations on the condition known as
"paces" are being conducted at this time.
1. Iron and Copper Deficiency (Nutritional Anemia). A more accurate
method for estimating the amount of copper in biological materials is
being developed in cooperation with the Spectrographic Laboratory.
Controlled feeding trials with calves on the efficacy of several forms
of supplements to correct nutritional anemia are being continued. Cod
liver oil was used in checking a possible relationship of nutritional anemia
to vitamin shortage, with negative results. Weekly hemoglobin determina-
tions have been made by the Newcomer method on all experimental animals.
A modified "salt sick" mineral formula for use on brackish-water, salt
marsh or tidal water ranges, was published. This formula, which has been
tried for several years, consists of 50 pounds of common salt, 50 pounds of
finely ground feeding bonemeal, 25 pounds of red oxide of iron and 1
pound of pulverized copper sulfate.
Mineral supplement intakes have been recorded over several years on
various groups of dairy heifers in relation to reproduction. Rate of repro-
duction has improved markedly since calves and heifers have had free
access to the regular "salt sick" mixture-100 pounds of common salt,
25 pounds of red oxide of iron and 1 pound of pulverized copper sulfate.
2. Calcium. Shortage of calcium in the customary rations formerly
fed to the Station dairy herd was overcome by adding 2 percent of finely
ground feeding bonemeal to the concentrates, beginning in 1929. Milk
records have been tabulated for 17 years and published. A total of 291
lactations were included, 73 made while the cows received calcium-adequate
rations. Average milk yield increased from 4,856 pounds to 7,092 pounds
per lactation.
3. Phosphorus. Laboratory studies were made in cooperation with Dr.
O. C. Bryan on relation of soil to phosphorus deficiency in cattle. Orange-
burg fine sandy loam, a soil on which range cattle are affected with phos-
phorus deficiency, contained less water-soluble phosphorus than did Leon
soils, and required greatest applications of this element to attain maxi-
mum growth of sorghum, vetch and mustard. A minimum of 0.5 parts
per million of water-soluble phosphorus was required in the soil to make
appreciable plant growth. Applications up to 4,000 pounds of super-






Florida Agricultural Experiment Station


phosphate per acre were needed for optimum growth and content of phos-
phorus in the forage. This work correlates with previous studies of
phosphorus content of bovine blood, and use of bonemeal to correct the
deficiency.
Further observations are being made as to the extent of ranges on
which cattle chew bones, which is an index of phosphorus deficiency in the
forages growing on such ranges.
4. "Paces." A soil reconnaissance was made and samples were obtained
on the (then) known ranges where cattle became affected with "paces".
Samples of grasses collected at regular intervals have been ashed and await
analysis. Two additional affected areas were located during the year.

COMPARISON OF VARIOUS GRAZING CROPS WITH DRY LOT
FEEDING FOR PORK PRODUCTION
Hatch Project 136 W. W. Henley
Since shotes finished for marketing during the latter part of August
and in September generally bring a higher price than later in the market-
ing season, it is important to provide early maturing grazing crops for
use in fattening the spring-farrowed shotes. For this purpose, Spanish
peanuts plus sweet potatoes; Spanish peanuts alone; Spanish peanuts plus
corn; and corn alone were used. Gains made during the 1935 grazing
season show that the grazing crops during this test period rank in the
following order: 1st, Spanish peanuts plus corn; 2nd, Spanish peanuts
plus sweet potatoes; 3rd, corn alone; and 4th, Spanish peanuts alone.
Work on this project was completed February 1, 1936.

RELATION OF CONFORMATION AND ANATOMY OF THE DAIRY
COW TO HER MILK AND BUTTERFAT PRODUCTION

State Project 140 R. B. Becker, W. M. Neal
and P. T. Dix Arnold

The Station has contributed three additional, total 32, records to this
cooperative project with the Bureau of Dairy Industry, U. S. D. A. A
second set of reproductive organs of a free-martin heifer was sent to
the same Bureau in cooperative studies.
The following animals were used during the past year in these studies:
Florida Matador Heiress F. 950797 with data on 2 lactations and one foetal
record; Florida Matador Lily 1006295, one lactation; Florida Fontaine
Wonder 988398, one lactation and one foetal record; and free-martin heifer
592 U. F.

FATTENING FALL PIGS FOR SPRING MARKET

State Project 160 W. W. Henley
In many instances two litters of pigs are obtained annually from brood
sows, the fall litter usually being farrowed during early September. Effort
has been made to determine the grazing crops best adapted for use in
finishing these pigs for marketing. During the 1935-36 grazing period
runner peanuts, and runner peanuts plus sweet potatoes were grazed,
and produced the same amount of pork per acre.
Work was completed on this project February 1, 1936.






Annual Report, 1936


A STUDY OF THE FEEDING VALUE OF CROTALARIAS
State Project 175 R. B. Becker, W. M. Neal
and P. T. Dix Arnold
The third and final double-reversal feeding trial with Crotalaria inter-
media versus Federal graded No. 1 alfalfa hay was conducted during the
past year. Final calculations will be made when the feed samples col-
lected during the trial are analyzed.
Naturally cured C. intermedia hay was fed to mules, and refusals
weighed. The heavier stems were rejected. Mules and cattle prefer the
early-cut hay.
The toxic principle of C. spectabilis, an alkaloid isolated and named
monocrotaline by workers in this department, was found to have a molecular
constitution of ClH20O. and a melting point at 196-197C. A brief account
of the toxicity of this plant appeared in the Journal of the American Society
of Agronomy.
This project is cooperative with the Agronomy Department and the
Bureau of Plant Industry, U. S. D. A., who have provided the forage and
seed.
SWINE FIELD EXPERIMENT
State Project 179 W. W. Henley
Work on this project has been discontinued.
A STUDY OF THE ENSILABILITY OF FLORIDA FORAGE CROPS
State Project 213 W. M. Neal, R. B. Becker
and P. T. Dix Arnold
Sugarcane from State Farm No. 2 at Belle Glade was ensiled at four
stages of maturity in the laboratory silos. Sugar content of the fresh
forage varied from 8 percent in July to over 14 percent in early December.
The later two stages made more palatable silage. Samples of freshly-
cut sugarcane were taken, and corresponding sample bags were placed
in each silo to study the changes in composition due to the ensiling process.
Thirty sample bags were placed at two levels in three trench silos
filled with either Napier grass, Red Amber Sorghum (Texas Seeded Ribbon
cane) or Cayana 10 sugarcane, to be used in conjunction with samples
of fresh forage in determining the efficiency of nutrient preservation in
this type of silo. Sample bags were placed at five levels in a 20-foot
upright silo filled with Crotalaria intermedia and corresponding fresh
samples were taken to measure losses due to ensiling. The silages were
used in Projects 241 and 175. Results of the three years' trials are being
tabulated.
BEEF CATTLE BREEDING INVESTIGATIONS
State Project 215 A. L. Shealy and W. W. Henley
Studies in the importance of using purebred sires with native cows
in grading up herds of cattle are being conducted at Penney Farms in co-
operation with Foremost Properties, Inc. The foundation cows were range
cattle with no improved blood in their breeding. A few first-cross heifers
were added to the breeding herds last year, and second-cross offspring
are now available for studies. Four foundation herds are being used
in these studies. These four herds are headed by bulls as follows: Lot 1,
Hereford; Lot 2, Devon; Lot 3, Brahman; and Lot 4, Red Polled.
The calves are graded as slaughter calves when three or four months
old.






Florida Agricultural Experiment Station


All heifer calves are retained for replacements in the breeding herd.
At three years of age all heifers are graded on the same scorecard as were
the native cows, and these grades are recorded. In this way it is possible
to show the improvement made by using purebred bulls.
Numerical valuations have been assigned all grades on the scorecard
and by this method of grading the following information has been obtained
on the three-year old heifers as compared with the native cows in each lot.
Lot 1-native cows 61.01-grade Hereford heifers ........ 73.24
Lot 2-native cows 60.38-grade Devon heifers .............. 74.01
Lot 3-native cows 62.44-grade Brahman heifers ........ 76.59
Lot 4-native cows 60.75-grade Red Polled heifers .... 70.89*
*The Red Polled heifers were two years old.
These studies are in cooperation with the Bureau of Animal Industry,
U. S. D. A.

COOPERATIVE FIELD STUDIES WITH BEEF AND DUAL-PURPOSE
CATTLE
State Project 216 A. L. Shealy and W. W. Henley
Because of great variation in Florida ranges, it was deemed advisable
to obtain data with beef cattle on various types of ranges. Studies are
being made on 23 ranges extending from Jackson County in the west to
Lee County in the south.
A large number of herds are included and there are great variations
in grades of native cattle comprising them. Likewise type of ranges and
herd management vary widely.
Bulls used are purebred Angus, Devons, Red Polled, and Shorthorns.
Native cows were used in the foundation herds; however, a number of
first-cross heifers have been added this year.
Observations include: Grades of cows composing breeding herds, percent
of calf crop, grades of calves as slaughter calves, grades of heifers when
three years old, types of ranges, mineral requirements on ranges, and
methods of wintering breeding herds.

DUAL-PURPOSE CATTLE INVESTIGATIONS UNDER
FARM CONDITIONS
State Project 217 A. L. Shealy
This project has been discontinued.

FACTORS AFFECTING THE PERCENTAGE OF CALF CROP
AND SIZE OF CALVES
State Project 218 A. L. Shealy
This project has been discontinued.

BEEF AND DUAL-PURPOSE CATTLE INVESTIGATIONS
State Project 219 A. L. Shealy and W. W. Henley
Studies are being made with beef and dual-purpose cattle as follows:
Herefords at the Main Station, Gainesville; Aberdeen-Angus at the North
Florida Station, Quincy; Devons at the Everglades Station, Belle Glade;
and Red Polled at the federal West Central Florida Experiment Station,
Brooksville. In addition to purebreds, native cows are kept at these
stations for making comparative studies with purebreds, grade offspring,






Annual Report, 1936 53

and native cattle. Data regarding the improvement made by using pure-
bred sires on native cattle are being obtained. All animals are weighed
every 28 days; birth weights and growth rate on all calves are recorded.
All native cows have been graded on a special scorecard for range cows.
As the grade heifers reach three years of age they are graded on identical
scorecards as were the natives, to measure the influence of the purebred
sires on the offspring. All bull calves are castrated and used in steer
feeding trials.
Milk production records are being obtained with the purebred Red
Polled cows at the Brooksville Station.
This project is in cooperation with the Bureau of Animal Industry,
U. S. D. A.

INVESTIGATIONS OF HEMORRHAGIC SEPTICEMIA IN CATTLE
AND SWINE
Purnell Project 236 D. A. Sanders
The causative organism of hemorrhagic septicemia, Pasteurella bovisep-
tica, has been isolated from blood of cattle showing clinical symptoms of
the disease. Heretofore such organisms have been isolated only from
carcass material or from the upper respiratory passage of animals carrying
the infection. These organisms were obtained from blood of cows that
developed the disease incident to shipping. Blood from sick animals,
during the early stages of the disease, did not show the presence of the
Pasteurella organisms. Animals from whose blood the organisms could
be cultured usually died, regardless of treatment. Recoveries were frequent
in animals less severely affected and in which no organisms were demon-
strated in the blood stream.
It was found that the Pasteurella organisms frequently appear as in-
vaders in the blood stream of cattle that died of anaplasmosis and Crotalaria
spectabilis poisoning. In these cases the organisms were more numerous
shorty after death, and were found most abundantly in those blood vessels
situated near the laryngopharyngeal region. The occurrence of Pasteurella
in bovine carcass material under these conditions and the virulency of such
organisms for small test animals cannot always be accepted as criteria in
judging the etiology and virulency for hemorrhagic septicemia in cattle.
Experiments showed that intestinal disorders and joint ill may result
in calves from infection of P. boviseptica. This organism has been isolated
from calves affected with bronchopneumonia.

THE DIGESTIBLE COEFFICIENTS AND FEEDING VALUE OF DRIED
GRAPEFRUIT REFUSE AND DRIED ORANGE REFUSE

Purnell Project 238 W. M. Neal, R. B. Becker
and P. T. Dix Arnold
Three calves have grown to a live weight of 700 pounds on rations
of dried grapefruit refuse and cut alfalfa hay, equal parts, and sufficient
cottonseed meal (41% protein) to meet protein requirements. Two Jersey
calves have attained weights of over 600 pounds in 14 months on a ration
of dried grapefruit refuse and cottonseed meal, 41/2 pounds of the former
to 1 of the latter, with 20 c.c. of cod liver oil daily. Two other calves re-
ceived dried grapefruit refuse, sorghum silage and cottonseed meal, with-
out cod liver oil supplement. Good growth and physical condition of these
animals were observed. The citrus refuse has a mildly laxative action,
and also causes the hair to have a glossy appearance, indicative of good
general condition of the animal.






54 Florida Agricultural Experiment Station

Steers were fattened on dried grapefruit refuse, and on fresh cannery-
run refuse, at the Citrus Station, Lake Alfred. These animals gained
weight in direct proportion to the intake of total digestible nutrients.
No objectionable qualities were imparted to the meat or fat, as verified
by palatability tests of these products conducted by workers in the depart-
ment in cooperation with Miss Beatrice Olson of the Home Economics
Department, P. K. Yonge Laboratory School.
Investigation will be made of other means of preserving this by-product
as feed during the coming year.

THE EFFICIENCY OF THE TRENCH SILO FOR PRESERVATION OF
FORAGE CROPS AS MEASURED BY CHEMICAL MEANS
AND BY THE UTILIZATION OF THE NUTRIENTS
OF THE SILAGE BY CATTLE
State Project 241 A. L. Shealy, W. M. Neal
and R. B. Becker
Napier grass, Texas Seeded Ribbon cane (Red Amber sorghum) and
Cayana 10 sugarcane were used in three semi-trench silos. The cut forage
was covered with two-ply roofing paper and approximately 2% feet of
soil. The roofing paper materially reduced top spoilage. Forage put
into each silo was weighed, and during the feeding trial all sound and
spoiled silages were weighed from the silos.
The steer feeding trial began on November 23, 1935, and continued for
130 days. Thirty-six grade Aberdeen-Angus, Hereford and Shorthorn
steers were divided as uniformly as possible into three lots of 12 each.
Steers in Lot 1 received Napier grass silage; Lot 2, sorghum silage; and
Lot 3, sugarcane silage. The concentrates consisted of 2 parts ground
snapped corn and 1 part cottonseed meal (41% total crude protein).
Sorghum silage gave best results, as in previous feeding trials. Feed-
ing value of Napier grass silage for this test proved to be somewhat greater
than for the previous one. This difference is believed due to cutting the
Napier grass at an earlier stage of growth. Sugarcane silage ranked third
in the 1935-1936 feeding trial.
All steers were graded as "feeder" steers at the beginning of the feed-
ing trial, and at the close were graded as fat steers. Slaughter data
obtained include dressing percent, carcass grade, and percent shrink in
cooler.

A COMPARATIVE STUDY OF CORN AND LIQUID MILK VERSUS A
GRAIN AND MASH RATION IN FEEDING FOR EGG PRODUCTION
State Project 244 N. R. Mehrhof and E. F. Stanton
This experiment was repeated in a 348-day test. Two pens of S. C.
White Leghorns of uniform age and breeding, reared under the same
conditions, were placed in two separate houses of similar design. There
were 40 pullets in each pen. All management practices were the same
for both lots. The feed for Lot 1 consisted of whole white corn and
liquid milk, for Lot 2 grain and mash.
Results of the second year's work follow.
Lot 1 Lot 2
Number of birds at beginning .................... 40 40
Mortality (number) ................................ 21 18
Eggs per bird per year ................................ 98.72 155.33
Feed consumption per bird in pounds ........ 53.01 71.73
Pounds feed to produce one dozen eggs .... 6.43 5.53






Annual Report, 1986 55

This work was conducted at the Florida National Egg-Laying Contest
at Chipley.

A COMPARATIVE STUDY OF THE VALUE OF MEATSCRAPS, FISH
MEAL, AND MILK SOLIDS AS SOURCES OF PROTEIN
FOR EGG PRODUCTION
State Project 245 N. R. Mehrhof and E. F. Stanton
The feeding experiment to compare the value of different sources of
protein for egg production was repeated.
Four lots of Single Comb White Leghorn pullets of uniform age and
breeding and reared under the same management practices were placed
in four separate houses of similar design. Forty pullets were placed in
each lot under uniform management practices.
The basal ration consisted of bran, shorts, yellow cornmeal, ground
oats, alfalfa leaf meal, oyster shell and salt.
Supplemental feed was added to the basal ration as follows: Lot 1,
meatscraps; Lot 2, meatscraps plus dried buttermilk; Lot 3, fishmeal; and
Lot 4, fishmeal plus dried buttermilk.
The following data were obtained:
Lot 1 Lot 2 Lot 3 Lot 4
Number birds at beginning ........................ 40 40 40 40
Mortality (number) .......................... 18 18 17 13
Feed consumed per bird in pounds ............ 71.73 72.60 72.11 73.11
Eggs per bird ........... ...................... .. 155.33 128.35 153.28 135.30
Pounds feed to produce one dozen eggs .... 5.53 6.78 5.64 6.48
This work was conducted at the Florida National Egg-Laying Contest
at Chipley.

LIGHTS VERSUS NO LIGHTS FOR EGG PRODUCTION ON SINGLE
COMB WHITE LEGHORN PULLETS AND HENS
State Project 246 N. R. Mehrhof and E. F. Stanton
This experiment was repeated (October 13, 1934-September 25, 1935)
to study the effect of morning lights on egg production.
Two lots of 40 S. C. White Leghorn pullets of uniform age and breed-
ing and reared under the same conditions were placed in two separate
houses of similar design.
All feeds and management practices were the same for both pens with
the exception of light. The birds in Lot 1 received artificial illumination
in the early morning while Lot 2 birds did not.
The following data were obtained:
Lot 1 Lot S
Number of birds at beginning .................. 40 40
Mortality (number) ...................................... 17 18
Feed consumption per bird in pounds ........ 76.57 71.73
Eggs per bird (year) .................................. 149.84 155.33
Eggs per bird (first 150 days) .................. 61.72 59.76
Pounds of feed to produce one dozen eggs 6.13 5.53
The experiment with hens began October 13, 1934, and was continued
for 348 days. Eighty-four hens were divided according to age and breed-
ing into two lots of 42 each. The feed used in both pens was the same.
All management practices were similar except that Lot 1 received artificial
illumination in the early morning while Lot 2 received no additional light.
The data for the first year's work are given.







Florida Agricultural Experiment Station


Lot 1 Lot 2
Number of birds at beginning .................. 42 42
Mortality (number) ........................................ 11 7
Feed consumption per bird in pounds ........ 76.72 74.54
Eggs per bird (year) .................................... 154.09 149.39
Eggs per bird (first 150 days) .................... 62.20 43.21
Pounds of feed to produce one dozen eggs 5.98 5.99
This work was conducted at the Florida National Egg-Laying Contest
at Chipley.

EFFECT OF FEEDING COLON ORGANISMS AND DRIED WHEY ON
THE BACTERIAL FLORA OF BABY CHICKS AFFECTED
WITH PULLORUM DISEASE
State Project 250 M. W. Emmel
A baby chick starting mash containing 15 percent dried whey fed
during an outbreak of pullorum disease in baby chicks has been found
effective in preventing the spread of infection from sick chicks to healthy
ones. It should be continued until the chicks are three weeks of age.
This ration should not be fed as a preventive to healthy flocks of baby
chicks as it contains too much lactose. Trials in which this feed was
used on widely scattered farms have given satisfactory control of pullorum
disease.
This project has been concluded with this report, and results will be
published during the coming year.

THE ETIOLOGY OF FOWL PARALYSIS, LEUKEMIA AND ALLIED
CONDITIONS IN ANIMALS
State Project 251 M. W. Emmel
Studies have been made to determine the influence of parasitism in
fowl paralysis, leukemia and allied conditions. These studies showed that
intestinal parasites create a favorable environment for the paratyphoid
and typhoid organisms. From the intestinal tract, these organisms gain
entrance into the blood stream through lesions produced by parasites.
In this study the micro-organism, Salmonella aertrycke, was found in
the intestinal contents of five birds affected with enteritis associated with
coccidiosis, S. enteritidis in three birds, S. typhimurium in two birds while
S. schottmulleri, S. suipestifer, S. pullorum and Eberthella typhi were
found in the intestinal contents of but one bird each. The percentage
occurrence of these micro-organisms ranged from 8.7 to 61.4 percent of
the total bacteria flora.
The intestinal contents of 18 birds affected with enteritis associated
with roundworms and tapeworms alone, or in combination, were examined
and S. aertrycke was isolated from the intestinal contents of four birds,
S. typhimurium from two birds while S. enteritidis, S. paratyphi, Shigella
paradysenteriae, Eberthella typhi and E. enterica were isolated from the
intestinal contents of but one bird each. The percentage occurrence of
these micro-organisms ranged from 25.8 to 58.6 percent of the total
bacterial flora.
'The foregoing micro-organisms were found in routine examinations
of the intestinal contents of 137 out of 230 birds affected with enteritis
associated with coccidia, roundworms and tapeworms.
The conclusion is reached that intestinal parasitism seriously inter-
feres with the normal flora, thereby allowing micro-organisms of the
paratyphoid and typhoid groups to become established in the intestinal
tract.






Annual Report, 1936


It was difficult to produce fowl paralysis, leukemia and allied condi-
tions in birds that were free from internal parasites when such birds were
given oral exposures to the causative organisms. However, when birds
affected with chronic intestinal parasitism were exposed to the organisms,
a high percentage developed symptoms of these diseases.
The incubation period for fowl paralysis varied from 17 to 63 days,
lymphomatosis 45 to 104 days, leukemia 70 to 172 days and "light" and
anemia, 14 days.
Leukemia has been induced in the monkey, dog, hog and sheep by the
proper exposure to S. aertrycke and S. enteritidis. In the monkey, as
in the chicken, members of the typhoid group are more capable of in-
ducing aleukemic types of this group of diseases.

A STUDY OF PLANTS POISONOUS TO LIVESTOCK IN FLORIDA

Purnell Project 258 D. A. Sanders, M. W. Emmel
and Erdman West
Studies have shown that the symptoms of chronic Crotalaria spectabilis
poisoning in cattle may appear several weeks after exposure to small
quantities of the mature plant and seeds. Gross lesions observed in
advanced cases of long standing consist of an indurated liver, enlarged
gall bladder, icterus and edema. Microscopic examination of the liver
showed a replacement of the functioning cells with fibrous tissue.
Young cockle-bur plants were found to be toxic for swine. Young
pigs are highly susceptible to the toxic principle. The cockle-bur seeds
sprout early in the spring when there is little green grazing and pigs
eat the young plants readily.
Losses have been observed in yearling calves that were restricted for
several days on areas on which the vegetation consisted mostly of oak
bushes. Preliminary feeding trials indicate that such losses may be due
to oak leaf poisoning.
The seeds of Crotalaria retusa have been found to be toxic for chickens,
the number of seeds required to induce death being slightly less than in
the case of C. spectabilis. The gross pathologic lesions are quite similar
to those induced by C. spectabilis which include innumerable hemorrhages
on the serious membrane and visceral fat, dark colored liver in the acute
type and necrotic enteritis, ascites and anemia in the chronic type of
poisoning.
Samples of several Florida plant seeds poisonous to animals were
collected and filed in the herbarium for further reference in identification,
and this collection will be increased as opportunities permit. This collec-
tion has already been used to identify Daubentonia seeds obtained in
postmortem of a chicken.

DEFICIENCIES OF PEANUTS WHEN USED AS A BASAL RATION
FOR SWINE
W. G. Kirk
Peanuts are one of the most important feed crops grown in Florida.
A large number of hogs are fattened each year on peanuts and many
breeding herds are grazed mainly on this feed crop during the winter
months. Growing hogs, pregnant and lactating sows fed entirely on
peanuts for several months often develop a serious bone condition which
results in posterior paralysis.
Studies are being made to determine the cause of this condition and
the means for correcting it.






Florida Agricultural Experiment Station


CHEMISTRY AND SOILS

The work of the department has not differed materially from that
of previous years. In addition to work on the various projects, some 500
soil acidity determinations were made for other departments, county agents
and various individuals.
R. M. Barnette devoted approximately three months at the start of
the fiscal year assisting in a soil survey of the state for the U. S. Depart-
ment of Agriculture as a part of the project, "A Study of Adjustment in
Farming by Regions and Type-of-Farming Areas from the Standpoint of
Agricultural Adjustment and Planning, Including Soil Conservation".
Facilities for conducting celery studies at Sanford have been greatly
improved through the cooperation of the County Commissioners of Seminole
County, the officials of the city of Sanford and the federal Works Progress
Administration. A new laboratory building with greenhouse attached was
constructed and approxiatmely five acres of tiled land made available for
field tests. The Chilean Nitrate of Soda Educational Bureau furnished
a pump and motor for irrigation purposes.

DETERMINATION OF THE EFFECT OF VARYING AMOUNTS OF
POTASH ON THE COMPOSITION, YIELD AND
QUALITY OF THE CROP
Hatch Project 22 R. W. Ruprecht
Results with citrus indicate that for seeded grapefruit a ratio of ap-
proximately 1 to 1 of nitrogen and potash in the fertilizer gives higher
fruit yields than a higher ratio of potash to nitrogen. The fertilizers with
a higher potash content apparently restrict the intake of nitrogen and
phosphoric acid by the trees, as the leaves and shoots from the high
potash plots had a smaller percentage of these elements than leaves and
shoots from the low potash plots.
The lower potash ratio had no apparent adverse effect on the quality
of the fruit.
This project is being discontinued.

DETERMINATION OF THE EFFECT OF VARIOUS POTASH CARRIERS
ON THE GROWTH, YIELD AND COMPOSITION OF CROPS
Hatch Project 37 R. W. Ruprecht
Tree measurements at the Citrus Station show that during the past
two years orange and grapefruit trees in plot 1, receiving all potash from
high grade sulfate, have made greater growth, judged by increase in trunk
circumference, than those on any other plot. Tangerines on plot 3, receiv-
ing low grade sulfate of potash magnesia, made the largest growth. High-
est yields of tangerines and oranges were on plot 3 with highest grapefruit
yields from plots 5 and 6, which received some sulfate of potash and
some muriate.

THE EFFECT OF VARIOUS FERTILIZER FORMULAS
State Project 94 R. W. Ruprecht
Citrus. An effort is being made to determine the cause of poorer growth
and condition of trees on plots receiving superphosphate than those re-
ceiving bone meal. Pineapple oranges yielded highest on the nitrate of
soda plot when superphosphate was used. However, a considerable per-
centage of the fruit was ammoniated. When bone meal was used the







Annual Report, 1936 59

dried blood plot gave highest yield and a high quality of fruit. The yield
from this plot was only slightly higher than that from the sulfate of
ammonia plot or the plot receiving half its nitrogen from sulfate of
ammonia and half from nitrate of soda, but quality of the fruit was
much better.
Analyses of fruit from these plots showed only slight differences.
Oranges from bone plots had higher acidity than those from superphos-
phate plots. Fruit from nitrate of soda plots, whether receiving super-
phosphate or bone meal, had a higher nitrogen content than any of the
others.
Potatoes. An exceptionally cold and wet spring, coupled with a severe
case of late blight, cut down the yield of potatoes on experimental plots
at Hastings.
A complete mixture analyzing 5-7-5 (NH3-PO2s-K.O) applied at the
rate of 2,000 pounds per acre was used as the basis for a series of fertilizer
tests on potatoes. In the source of nitrogen tests with this mixture, calnitro
again produced the highest yields with calurea closely following. Reduc-
ing the percentage of phosphoric acid from 7 percent to 2 percent did not
affect yield.
The standard 2,000 pounds per acre rate of application was compared
with 3,000 pounds, and with 2,000 pounds and an additional 500 pounds
top-dressing. The larger applications gave slightly increased yields. De-
creasing the usual 5 percent of ammonia to 4 percent gave somewhat lower
potato yields; however, increasing to 6 percent failed to give greater
yields. The addition of compounds of magnesium, copper, zinc and boron
had no effect on yields.

CONCENTRATED FERTILIZER STUDIES
State Project 95 R. W. Ruprecht
The fertilizer experiment with citrus at Lake Alfred in cooperation
with the U. S. Department of Agriculture was discontinued. The grove
was in excellent condition, having fully recovered from the over-fertilization,
freeze and drought. The highest yield was obtained with a fertilizer
made from ammonium phosphate, sodium nitrate and sulfate of potash.
All of the concentrated fertilizers gave higher yields than the normal
strength fertilizer.
In the experiments at Lake Harris, fire destroyed a large section of
the grove last fall and the experiment has had to be abandoned.
Results obtained from this experiment indicate that urea is a satis-
factory source of nitrogen for citrus. In addition, it has been observed
that one application per year of a concentrated fertilizer containing nitro-
gen, phosphoric acid and potash, with nitrogen sources alone for the
two other applications, produced as satisfactory tree growth as did three
applications of regular strength fertilizer (containing N-P-K) during
the year.

DETERMINATION OF THE EFFECT OF GREEN MANURES
ON THE COMPOSITION OF THE SOIL
Adams Project 96 R. M. Barnette
Experiments to determine the cause of the failure of crotalaria to
make satisfactory growth in the deep sandy soils of the Ridge have been
discontinued. None of the materials added to the soil gave any increase
in growth or stand of either Crotalaria spectabilis or G. striata.







Florida Agricultural Experiment Station


The phytometer studies on the comparative rate of decomposition of
Crotalaria striata, C. spectabilis and C. intermedia were repeated. Again
the mature C. spectabilis decomposed at a more rapid rate than did the
other two as measured by residues of these crops left in the soil after
a definite period of decomposition.

A STUDY OF CHLOROSISS" IN CORN PLANTS AND OTHER
FIELD CROP PLANTS
Adams Project 220 R. M. Barnette
Field work now in progress in cooperation with the Agronomy Depart-
ment includes a study of the residual effect of the application of zinc
sulfate to corn for the prevention of white bud. Corn growth following
the application of both 12 and 36 pounds of 89% zinc sulfate in 1935
appears healthy and vigorous this growing season. Plants on plots with-
out zinc sulfate are definitely chlorotic. The application of an additional
12 pounds of zinc sulfate in 1936 to plots treated with either 12 or 36
pounds of zinc sulfate in 1935 has to date shown no outstanding improve-
ment in plant vigor over the plots receiving the zinc sulfate only in 1935.
In addition, field experiments are being conducted to test different
sources of zinc for the prevention of white bud of corn. Two zinc ores
sulfidess), zinc oxide, zinc ammonium chloride, powdered zinc, zinc nitrate
and zinc sulfate are being compared. Treatment with zinc oxide and zinc
sulfate of seed corn prior to planting is being tried. Germination of treated
seed was slower than that of untreated checks but no decrease or injury
was observed. Corn plants from treated seed showed few symptoms of
white bud in the early growth stages but after approximately four weeks
some became partially chlorotic. One of the ores has not proved bene-
ficial in preventing white bud, while the other which contains some soluble
zinc has proved effective. Metallic zinc has not proved especially bene-
ficial in preventing white bud when applied in the drill at the rate of
5 pounds per acre, but was effective at the 40 pounds per acre rate. Soluble
zinc salts have all been effective.
Oats receiving a broadcast application of 15 pounds of 89% zinc sulfate
before planting matured earlier than those without zinc sulfate.
In tests with miscellaneous field crops, velvet beans and millet developed
definite physical symptoms of zinc deficiency when grown on land pro-
ducing white bud of corn.
Results of work with zinc sulfate on field crops through the 1935
crop season were published in Bulletin 292.

BRONZING OR COPPER LEAF OF CITRUS
State Project 223 C. E. Bell and R. W. Ruprecht
Calcium, limestone and dolomite have been applied to 11-year-old
Valencia orange trees since 1933. The soil is Norfolk sand (deep phase).
Applications of limestone and dolomite have changed the pH values of the
0-9 inch soil depths from 1933 to 1936 as follows:
Treatment Pounds per Tree pH
No limestone ......................... .-.... ...... .. ......- 5.07 to 5.17
Limestone ............................. .....- 16.5................ 4.73 to 5.23
Lim estone ........................................33.0................ 4.88 to 5.20
Lim estone ........................................49.5................ 4.69 to 5.37
Limestone ................................--........99.0................ 5.08 to 5.43
Dolomitic limestone ........................49.5................ 4.88 to 5.07
Limestone ........................................ 5 4 4.75 to 5.20
Magnesium sulfate ...................-...53.6 .






Annual Report, 1936


During this period, replaceable calcium and potassium have increased
in all plots. Replaceable magnesium has increased only in plots receiving
magnesium compounds. All symptoms of bronzing have disappeared from
the trees but recovery has not been correlated with the application of
any of the fertilizers or liming materials.

THE OCCURRENCE AND BEHAVIOR OF LESS ABUNDANT
ELEMENTS IN SOILS
Adams Project 240 R. M. Barnette
A bulletin covering studies of the reaction of zinc compounds in the soil
has been published. This bulletin covers laboratory studies on the fixation
and solubility of zinc in the soil as well as greenhouse studies on the limits
of toxicities of zinc in Norfolk sand.
Studies on the toxicity of zinc in Orangeburg and Greenville soils show
that 400 ppm. of Zn in replaceable form was toxic to corn. Calcium car-
bonate at the rate of 4,000 pounds per acre overcame the toxicity. The
toxicity in Norfolk sand was at a concentration of 300 ppm. which could
be corrected with 1,000 pounds per acre of calcium carbonate.
Work is still in progress on a better method for determining small
amounts, less than 5 milligrams, of zinc. In this study a comparison
between the chemical and spectrographic methods for zinc in plant ashes
is in progress.

SOIL AND FERTILIZER STUDIES WITH CELERY
State Project 252 E. R. Purvis and R. W. Ruprecht
Further experiments with borax confirmed the results obtained last
year, namely, that small applications of this material will prevent the
development of cracked stem. Apparently boron is not fixed in the soil
and annual applications will be necessary to prevent cracked stem, as
this trouble developed on plots that received borax last year but none
this year. The amount of borax that will produce toxic effects is influenced
by the amount of rainfall. Fifty pounds per acre this year when rainfall
was abundant did not give as great toxicity as 30 pounds last year.
Further trials with other rare elements were carried out on two farms.
In both locations no one single element produced significant increased yields.
However, on both farms a combination of manganese sulfate, zinc sulfate
and cobaltous chloride gave significantly increased yields, although when
used separately they gave no response. The possibility of plants requiring
the less common elements in amounts depending upon a definite ratio
between these elements is suggested.
In the fertilizer experiments no single source of nitrogen yielded
significantly higher than the check plot. Sulfate of ammonia produced no
marketable celery on one of the plots and only a small yield on the
duplicate plot. This quite likely was due to the acidity of the soil as
these plots had a pH reading of 4.94 and 4.86. Cyanamid produced a small
crop of small celery. This material very evidently cannot be used for
top-dressing. Increasing the phosphoric acid content in the fertilizer from
3% to 6% again gave significantly higher yields.
It was found that hydrated lime kept the soil reaction more constant
than any other liming materials. No increased yields were obtained.
This probably was due to the fact that the reaction of the soil was already
slightly above pH 6.0 which has been found to be the optimum for celery
on this type of soil.







Florida Agricultural Experiment Station


Preliminary experiments seem to indicate that black heart of celery is
caused by the presence of the nitrite form of nitrogen in the soil. Further
greenhouse, laboratory and field studies are under way to confirm these
findings and find methods of prevention.

NUTRIENT SALT CONCENTRATION IN THE SOIL WITH SPECIAL
REFERENCE TO THE TRACE ELEMENTS
R. B. French
The purpose of this study is to secure information upon the place of
the "trace elements" in the economy of the plant. For the first experi-
ments tomatoes were grown in quartz sand under greenhouse conditions
at different concentrations of a nutrient solution (Knop's four salt solution)
which contains all the elements necessary according to classical plant
nutrition. This set of plants was compared with others receiving the
same basic treatment with the addition that one set of plants received all
the known apparently essential trace elements, and another received the
further addition of other trace elements that have been suggested as pos-
sible beneficial factors influencing plant nutrition.
After growing vigorously and tripling in size the tomatoes stopped
growing. The leaves became a very much darker green and started to
curl tightly. Death of the growing point and auxiliary buds occurred
and the petioles died back. Boron was found to correct this condition.
Concentrations of 2.1, 3.5 and 7 ppm. of boron in the nutrient solution
were found equally effective. Judged by the new growth produced, the
higher levels of boric acid caused a more efficient utilization of the nutri-
ents in the more concentrated solution.
Corn grown in nutrient sand cultures lacking in boron produces a
symptom that is similar to that of the boron deficient tomato plant. The
cells of the older leaves become almost completely disorganized. The new
leaves fail to uncurl and death of the apical portion occurs, followed by
the dying back of all new growth.
The iron requirements of young corn plants as judged by the pro-
duction of a typical chlorosis could be satisfied by a concentration of 3 ppm.
of Fe as FeSO4 or 100 ppm. as ferric citrate. The degree of chlorosis
appeared the same in plants supplied with 0.5 ppm. Fe as FeSO., 100 ppm.
as Fe(NOs), or with 25 ppm. as ferric citrate.

INVESTIGATION OF VITAMIN C CONTENT OF
FLORIDA FRUITS AND VEGETABLES
R. B. French
A few determinations of vitamin C have been made. In the tomato,
vitamin C develops slowly in the green tomato, reaches a maximum shortly
before maturity, and then decreases.
Fresh celery leaves contained 20 mgm. of vitamin C (ascorbic acid) per
gram. This is the richest source of this vitamin yet found.
Preliminary studies on the vitamin C content of oranges indicates
that the loss of this vitamin is fairly rapid once the fruit is picked and
kept at ordinary room temperatures.

MINERAL CONTENT OF VEGETABLE CROPS
H. W. Winsor
This study is conducted in cooperation with the Home Economics De-
partment as an adjunct to its research in nutritional anemia.






Annual Report, 1936 63

Considerable time has been spent in perfecting a method for determin-
ing iron in plant materials, as existing methods have proven unsatis-
factory.
Turnip and mustard greens grown under average conditions were
exceptionally high in calcium and iron; but when grown on an iron-deficient
soil such as Leon fine sand showed a materially lower iron content. Pre-
liminary studies indicate that the Leon sand and similar soils produce
vegetables of low iron content even when treated with optimum quantities
of cow manure, complete fertilizer, or fertilizer plus 100 pounds of ferrous
sulfate per acre.






64 Florida Agricultural Experiment Station

ENTOMOLOGY

Work in this Department was conducted under 14 projects. Twelve
of these had to do with insects, one with vertebrate pests, and one with
nematodes.
One outstanding result of the year's work was the demonstration that
a thorough clean-up of pepper fields during the summer was a very
effective method of checking the pepper weevil, almost amounting to
eradication, and that eggplants and nightshade are not important hosts
during this period; also, that a thorough and constant campaign of dusting
with calcium arsenate and picking up of dropped peppers will result
in holding the pest in check.
In nematode work the discovery of a very resistant strain of conch
cowpeas was a valuable find.
Surveys of the ecological habitats and host plant surveys of both
aphids and thysanoptera were conducted as during previous years.
In addition to work on projects, much time was spent in giving advice
of an entomological nature to farmers and householders through the agri-
cultural press, radio addresses, press bulletins, personal visits and talks
to meetings of farmers.

THE FLORIDA FLOWER THRIPS
(Frankliniella cephalica bispinosa Morgan)
State Project 8 J. R. Watson
Weather during the past winter was very unfavorable for the develop-
ment of this insect, the early part of the winter being unusually dry and
cold, which prevented many plants from blooming. February was very
wet and cold, further checking the development of blossoms, with the
result that the thrips were scarcer in citrus blooms than they have been
for many years, averaging only two or three per bloom. The bloom was
heavier than usual this spring, resulting in further lightening of the
infestation. Under these circumstances no control measures were at-
tempted on citrus.
Some work done during the fall on chrysanthemum plants, using the
poison bait recommended for gladiolus thrips, gave indications of being
of some value.
A survey of the thysanoptera of Florida was continued. Between 20
and 30 additions to the thysanopterous fauna of the state were made.
Nearly half of these species are undescribed. Knowledge of the ecological
and seasonal distribution of these insects was much extended. In the
state as a whole the black Haplothrips gowdeyi Hood was found to be
the second most common flower thrips. Mr. Goff has found the West Indian
flower thrips, Frankliniella insularis Franklin, to be very common in
the Bradenton section, common enough to be of some economic importance.

ROOT-KNOT INVESTIGATIONS
Adams Project 12 J. R. Watson and H. E. Bratley
Perhaps the most worthwhile development of this project was the
discovery of a strain of conch cowpeas which appears to be extremely
resistant to root-knot. This cowpea seems to be even more resistant
to root-knot than either Iron or Brabham. Its resistance was discovered
too late in the season to make it possible to save any seed. Fortunately,
some of the seed purchased last year was saved. It has been planted in
a section removed from other cowpeas so there will be no crossing, and






Annual Report, 1936


all the seed will be very carefully saved. No information is available as
to its origin.
Work with root-knot has been largely an attempt to develop resistant
strains of some of the truck crops, especially lettuce, tomatoes, and pep-
pers. Samples of all varieties of these plants available last year were
planted in heavily infested soil and seeds from those showing most re-
sistance were saved and used for planting experiments this year. Flowers
from these plants have been bagged and pollinated by hand to eliminate
the possibility of crossing with less resistant plants. It seems some
progress has been made towards obtaining a resistant strain of lettuce,
also of the ornamental pinks. Work along the same line has been done
with a strain of Kentucky Wonder beans, obtained from the Alabama
Station, which seems to be quite resistant to root-knot. Selection work
is under way to obtain a strain even more resistant.
Work on the determination of the susceptibility or resistance to root-
knot of the more commonly planted annual ornamentals has been continued.
Preliminary findings have been published in Bulletin 291.

INTRODUCTION AND PROPAGATION OF BENEFICIAL INSECTS
State Project 13 J. R. Watson and W. L. Thompson
As during the previous year, work on this project had to do entirely
with study of the behavior of the Chinese ladybeetle, Leis dimidiata var.
15-spilota Hope. The colony in the northern part of Orange County has
continued to spread in a very satisfactory manner, as was to be expected,
with an increased acceleration as the area occupied became larger. They
were most abundant this year, not in the area where they were first
introduced, but in the outlying, newly occupied sections of their range.
They are now found in a region about 30 miles in diameter.
Comparative scarcity in the central part of the range where they
have been longest established was apparently due to their having reduced
the food supply to such an extent as to keep down their numbers. Control
of the green citrus aphid was very effective in this section this season,
practically no commercial damage being inflicted. As during previous
years, it was demonstrated that the weak point in their life history is
during the summer time when aphids are very scarce. During the winter,
also when aphids are often scarce, considerable numbers of the beetles
hibernate. Life history studies in the insectary showed that many hiber-
nated during the winter and observations in the field indicate that this
is a considerable factor in carrying them over.
As during previous years, they appeared first and most abundantly
in groves on the outside rows of trees. It is becoming even more evident
that this is a very efficient predator of the green citrus aphid, but one
difficult to establish in a region. Once it is established it seems able to
persist under rather adverse climatic conditions and scarcity of food.
Efforts were made to disseminate it further.

THE LARGER PLANT BUGS
State Project 14 H. E. Bratley
Studies and observations of plant bugs were continued. Due to heavy
parasitization of Nezara viridula by Trichopoda pennipes in 1934 and 1935,
the population was much decreased. In the summer and fall of 1935
there was a larger percentage of parasitization than usual. Late obser-
vations in some areas revealed but very few parasites.
Parasitization by Trichopoda pennipes also increased on Leptoglossus
phyllopus. Counts showed that from 20 to 50 percent of these leaf-footed







66 Florida Agricultural Experiment Station

plant bugs bore the parasite eggs. Acanthocephala, the big thighed plant
bug, was also parasitized by Trichopoda pennipes to about 10 percent.
All of these plant bugs were found feeding on thistle early this spring,
but not so abundantly as in former springs. The decreased population
of each may have been due to the severity of the 1935-36 winter and also
to the activities of parasites. They were not the serious pests they had
been to crotalaria and citrus.
In some areas where, during former years, a heavy parasitization was
observed there were but very few Nezara viridula found and no parasitic
eggs noted, but these areas were very few. The parasitization of Nezara
was somewhat lower this spring, indicating that perhaps Trichopoda has
reached its climax and that the next few years may show an increase
in numbers of plant bugs.
BEAN JASSID INVESTIGATIONS
Adams Project 28 A. N. Tissot
Observations have been continued on the distribution and abundance
of jassids during the past year. These insects were very troublesome and
destructive in northern Florida in the fall of 1935 and in the southern
part the following spring. Control experiments were conducted to test
relative effectiveness against jassids of pyrethrum and rotenone-bearing
dusts, sulfur being the diluent used with both. Dusts containing pyrethrum
gave an immediate kill of jassids far superior to that obtained with dusts
containing rotenone. However, a week after the applications were made
there was not so much difference between the pyrethrum and rotenone
dusted plots, though the advantage was in favor of the pyrethrum.
This project has been discontinued.
THE GREEN CITRUS APHID
Adams Project 60 W. L. Thompson and A. N. Tissot
The first of the winter was very dry, with the result that there was
practically no new growth on young trees and no food for aphids. This
resulted in about the lightest infestation on citrus since the aphid first
appeared in 1924. No work in the control of this aphid was attempted at
the Lake Alfred Station. Some of the newer insecticides were compared
with standard nicotine products, and although some of them seemed to
be excellent aphicides they gave no promise of being a marked improve-
ment over the insecticides now in use.
This project has been discontinued.

CONTROL OF FRUIT AND NUT CROP INSECTS-INSECTS
AFFECTING PECAN TREES
State Project 82 G. B. Fairchild and H. E. Bratley
In last year's report a description was given of the hexagonal plat-
forms of galvanized iron screening placed under six trees in the Monti-
cello section for the purpose of collecting all drops from pecans so that
the cause of dropping of the young nuts might be determined. These
drops were collected weekly and the cause of their fall determined as
accurately as possible. Shuckworm accounted for from .9 to 12.5 percent
of the drops, an average of 7.1 percent. The nut case-bearer accounted
for from 4.4 to 7.1 percent, with an average of 5.9 percent. From 54.2 to
100 percent of the crop dropped from causes not apparently connected
with insect damage. Of these drops drouth probably caused the vast
majority, though some early droppings were apparently of unfertilized nuts.







Annual Report, 1936


Some preliminary experiments were made with winter sprays for leaf
and nut case-bearer. Of these a solution of lye seems to give some promise.

CONTROL OF SCALE-INSECTS OF WOODY ORNAMENTALS
State Project 157 J. W. Wilson
The only work done on this project during the last year was some spray-
ing of arbor vitae infested with the arbor vitae aphid, Cinara tujafilina
(Del Guerico). It was found that these aphids could be controlled by
an application of nicotine sulfate spray.
This project has been discontinued.

INSECT AND OTHER ANIMAL PESTS OF WATERMELONS
State Project 162 C. C. Goff
Due to the transfer of Mr. Goff to Bradenton on the pepper weevil
project, no work was done on this project during the past year.
The project has been discontinued.

BIOLOGY AND CONTROL OF FIELD MICE IN WATERMELON
PLANTINGS
State Project 214 C. C. Goff
The only work on this project done this year was a general scouting
in the Bradenton section. No white-footed mice were found in that area.
This project has been discontinued.

THE ONION THRIPS (Thrips tabaci Lindin)
State Project 231 J. R. Watson
Onion thrips again appeared on celery in the Sarasota section, but
not until very late in the season when the harvest was practically com-
plete. However, the infestation was sufficiently severe to cause many
growers to harvest their celery a week or 10 days before they otherwise
would have done so.
A search for the wild hosts of this thrips was continued, and many
plants were added to the list of hitherto known hosts.

THE GLADIOLUS THRIPS (Taeniothrips gladioli M. & S.)
State Project 232 J. R. Watson and J. W. Wilson
Life history studies of this thrips being conducted at the Leesburg
laboratory were continued during part of the year, but after the storm
of September 1935 no thrips were found for several months, which caused
the life history work to be discontinued during this time. It was found
that during June, July and August the life span of the insects was very
much shortened, and the number of eggs laid remarkably reduced. Average
number of eggs laid during June, July and August was only 14.3 per
female, whereas during February it was 96. Evidently climatic conditions
during summer were very unfavorable for the development of this insect
and this accounts for the low infestations during the fall of the year.
As during previous years, breeding was most rapid during late March
and April.
About 4,000 gladiolus bulbs were planted but the infestation was not
sufficiently heavy to conduct any further experiments on control. During
the spring months colonies of this thrips were placed on the following







Florida Agricultural Experiment Station


plants, which are more or less closely related to the gladiolus: Ixia,
Eucharis grandiflora, Crinum powelli, Marica gracilis, Sparaxis, Freesia,
Tritonia crocata, Narcissus, and Amaryllis. Again, as last year, thrips
failed to survive on any of these plants.

BIOLOGY AND CONTROL OF THE FLORIDA APHIDS
State Project 234 A. N. Tissot
On the basis of severity of infestation and injury to cultivated plants,
aphids have been of less importance during the past year than in any of
the preceding three or four years. This was probably due to the con-
tinued cool weather of winter, which tended to reduce aphid population
to a minimum. It was impossible to continue studies of predators and
parasites of Aphis spiraecola Patch, as this aphid was found in the citrus
groves near Gainesville only during July and in very small numbers dur-
ing the latter part of November 1935.
Considered from the standpoint of species found, aphids have been
more common than in any year since 1928. One hundred five collections
of Florida aphids were recorded, representing 56 species, of which 8 species
have not hitherto been reported from the state. Four of these 8 species
appear to be new to science, the others being Hyalopterus atriplicis (Linn.)
from Chenopodium album, Myzus monardae (Williams) from Koellia sp.,
Eriosoma rileyi Thos. from Ulmus americana, and Prociphilus imbricator
(Fitch) from Fagus americana. To the list of known hosts of Florida
aphids were added 21 species of plants.

THE PEPPER WEEVIL (Anthonomus eugenii Cano)
State Project 263 C. C. Goff and J. W. Wilson
Discovery of the pepper weevil in Florida last year, as recorded in
the annual report, led to the establishment of this project. Through the
cooperation of the County Agent, the Manatee Growers Association and
growers, a very thorough clean-up of the pepper fields was obtained dur-
ing June and July. Unfortunately, one plot of hot peppers was overlooked,
with the result that the weevil was carried over in this field and later
transported to another plantation on young pepper plants. These were
the only heavy infestations which occurred this spring. In addition, two
very light infestations were found in early May. Peppers in one of these
fields were promptly destroyed, but in the other they are still standing
(June 30) and have gradually built up a rather heavy infestation.
This experience has demonstrated that a thorough clean-up of pepper
fields at the close of the picking season in June, or even as late as July,
is an extremely effective method of controlling this weevil. Last year,
at this time, all fields in Manatee County visited were infested, most of
them so heavily that scarcely a pepper and very few blossom buds were
escaping the weevil.
Experiments, beginning in early May, were conducted on control by
picking up all dropped fruit and dusting the plants at intervals with a
calcium arsenate dust. Excellent control was secured when the work was
carefully and thoroughly done.
Life history studies have been carried on since discovery of the pepper
weevil early in the spring. As was to be expected, the life cycle was found
to be somewhat shorter than recorded for California, the only region in
which careful life history work on this insect seems to have been done.
The incubation period is about 2.5 3 days, larval period 7-8 days,
and pupal period 4-5 days. These figures may not include extremes for






Annual Report, 1936 69

the period of development now but they are approximately the times taken.
The period from the time the egg is laid until the adult emerges is around
14 17 days. About four days elapse before the female begins to lay eggs.
The period from egg to egg in one case was 18 days. A study made of
the weevil in California showed that the shortest period from egg to adult
was 16 days. At present the period in Bradenton is about two days less
and a more rapid building up of an infestation can be expected than occurs
in Calfornia.
The weevil will survive and feed for a considerable time on eggplant
and nightshade (Solanum sp.), as indicated by two groups confined on
these plants. On the former the average survival was 13.1 days and on
the latter 13.0 days. Survival on the ground cherry (Physalis sp.) was
4 days.







Florida Agricultural Experiment Station


HOME ECONOMICS
Research activities of the department were conducted under five projects.
Two have been completed and one discontinued. New projects dealing with
nutritional value, chemical composition and vitamin content of grapes,
honey and tomatoes have been submitted for initiation during the coming
year.
THE RELATION OF GROWTH TO PHOSPHORUS, CALCIUM AND
LIPIN METABOLISM AS INFLUENCED BY THE THYMUS
Purnell Project 142 C. F. Ahmann
In this study approximately 200 rabbits, 100 rats, and 24 chickens have
been used. It has been found that any condition producing a state of
malnutrition causes a decrease in size of the thymus. If the malnourished
condition persists and emaciation occurs, the glandular portions of the
thymus disappear and only the connective tissues remain. This condition
corresponds in a way to thymectomy. It has been demonstrated repeatedly
in this laboratory that the weight of a rabbit at maturity after thymectomy
at 4 weeks of age is 25 percent less than the weight of control litter
mates. (See Ann. Rept. 1931, p. 80.) However, animals operated on at
8 weeks of age weighed the same when fully grown as the controls.
Cholesterol studies indicate an increase in blood cholesterol in animals
thymectomized at 3 to 4 weeks.
This project has been discontinued.

A STUDY OF LECITHIN SYNTHESIS IN HENS ON A VITAMIN A
AND LIPOID FREE DIET
Purnell Project 198 0. D. Abbott
In the preparation of experimental diets many investigators have as-
sumed that animals can synthesize lipoids on diets free of fat and lipoid
compounds. The effect of such a diet on nutrition of chickens was de-
termined by feeding pullets a diet composed of 30 percent Merril-Soule's
dried skimmed milk powder and 70 percent polished rice, extracted with
alcohol (McCollum diet).
From this investigation the following conclusions have been reached:
(1) A diet composed of dried skimmed milk powder and extracted rice
is deficient in several constituents and is therefore unsuitable in determin-
ing the synthesis of lecithin by pullets. (2) On a modified diet consisting
of 60 percent extracted polished rice, 30 percent Merril-Soule dried skimmed
milk powder, 10 percent dried brewer's yeast, plus 1 cc. carotene daily, or
the above diet in which 5 percent of the yeast is replaced by 1 gram of
lecithin daily, hens remained healthy and played consistently for more than
a year. With less yeast and no lecithin the birds soon showed symptoms
of malnutrition and died.
The data accumulated over a period of three years cannot be inter-
preted as showing that hens on a lipoid and fat free diet are able to
synthesize lecithin. These findings are at variance with reports made
by several investigators.
This project has been completed.
A STUDY OF THE HEMATOPOIETIC TISSUES OF RATS ON A DIET
LOW IN VITAMIN A
Purnell Project 199 IN VITAMIN A D. Abbott
This investigation shows that chronic avitaminosis A in adults is in-
dicated by changes occurring in the white blood cells. The blood picture







Annual Report, 1936


on successive studies shows first an increase in polymorphic nuclear cells
with a definite shift to the left-this corresponds to the response to acute
infection. Concomitant with this there is an increase in large lymphocytes.
As the avitaminosis progresses the polymorphic nuclear cells count drops
and the young granulocytes, juvenile forms and myelocytes, increase. A
marked rise in large lymphocytes now occurs with a drop in small lympho-
cytes. This shift in the ratio of large to small lymphocytes is the most
outstanding change in the blood picture.
Similar changes have been observed in humans, especially in individuals
who have been malnourished for a long time. In the six hospital cases
on which data are available it was observed that a diet high in vitamin A
brought about great improvement in the blood picture and the nutritional
status. In young animals and in children the symptoms of acute avitamino-
sis A, xerophthalmia and pus in the glands about the head, are easily
recognized but heretofore there have been no recognized definite symptoms
indicating chronic avitaminosis in adults.
This project has been completed.

A STUDY OF THE PATHOLOGIC CHANGES IN TISSUES AFFECTED
BY DEFICIENCY DISEASES OR BY TOXIC SUBSTANCES
Purnell Project 222 C. F. Ahmann
One phase of the microscopic study of the tissues of animals on rations
deficient in copper and iron has been completed. Tissues from the fol-
lowing were studied: Range animals which had developed "salt sick",
animals deprived of copper and iron under laboratory conditions, and
animals which had recovered from "salt sick" (artificially produced) fol-
lowing iron and copper therapy.
The pathological findings in both range and laboratory were similar.
The heart showed fibrosis and myocardial degeneration; the liver fibrosis,
anemia, and necrosis of cells about the central vein; the spleen gave evi-
dence of malphigian body degeneration; the kidneys showed tubular de-
generation with much swelling of the interstitial tissue; and the areolar
and connective tissues colloidal swelling.
The h:stological picture of the animals which had recovered from
anemia following iron and copper therapy gave evidence of previous
damage as indicated by the presence of scar or fibrous tissue in both the
liver and heart.

AN INVESTIGATION OF HUMAN DIETARY DEFICIENCIES IN
ALACHUA COUNTY, FLORIDA, WITH SPECIAL REFER-
ENCE TO NUTRITIONAL ANEMIA IN RELATION
TO HOME GROWN FOODS
Purnell Project 255 0. D. Abbott
Hemoglobin determinations of 2,051 children of Alachua County have
been obtained. A special study was then made of the hemoglobin of 535
rural children in grades 1 to 3, inclusive. While a number of these
children had hookworm and malaria, no correlation appeared to exist
between these infections and the incidence of anemia. The incidence of
anemia, however, was found to be higher in the districts where the pre-
dominant soils were classed as marginal or deficient in relation to "salt
sick" of cattle than in districts where the soils were classed as protective.
A study was then made of the nutritive value of certain foods produced
on the farm. It was found that when all other factors were equal, milk
from a salt sick cow induced in young rats a greater degree of mal-







72 Florida Agricultural Experiment Station

nutrition than milk from a normal cow. Iron salts of different degrees of
purity when fed on the same level of intake served equally well in regen-
eration of hemoglobin of anemic rats. But vegetables grown on soils
deficient in iron were found to be low in iron and were not consumed in
amounts necessary for hemoglobin regeneration to normal levels.
Wide variations were found in the iron, calcium and magnesium content
of vegetables grown on different types of soil.
When anemic children were given suitable amounts of ferric ammonium
citrate, regeneration of hemoglobin to normal levels was rapid. This
demonstrated that iron was the limiting factor in the diets of these children.






Annual Report, 1936


HORTICULTURE

The Horticulture offices were moved in September from the Experiment
Station Building to the two-story residence building on the Radio Road,
and in December Dr. A. F. Camp was transferred to the Citrus Experi-
ment Station. During the year investigations in the department have
advanced along several major lines.
Refrigeration research with citrus has developed methods and equip-
ment for: (1) Short periods of refrigeration to stabilize the market at
times of overshipment; and (2) holding fruit in cold storage for two to
five months where such long holds may be profitable. Manuscripts on dif-
ferent phases of citrus fruit storage have been prepared for publication.
Zinc continued to give outstanding results in the control of frenching
in citrus, bronzing in tung-oil and rosette in pecans and black walnuts.
Field work with truck crops has been greatly increased at the Main
Station. A suitable tract of land was set aside and developed for this
purpose. The land has been laid out in plots, and irrigation provided for
approximately four and one-half acres, which is about one-half of the
area. Part of the work heretofore conducted in various parts of the state
will be carried here, and it will be possible for more complete records
to be secured.
Pecan investigations have developed an economical cover crop and fer-
tilizing program which maintains nut production under Florida conditions.
A bulletin was published on this phase of the work, the data showing that
winter and summer legumes have a markedly beneficial effect on the growth
and production of pecan trees.

VARIETY RESPONSE OF PECANS TO DIFFERENT SOIL TYPES,
LOCALITIES, ETC.
State Project 46 G. H. Blackmon
Most pecans in 1935 were produced in North and West Florida. The
lightness of the crop in the eastern part of the state was due mainly to
the defoliation in many orchards in 1934 by the walnut defoliator, and also
to cold damage in March 1935. Leaf and nut case-bearers, also, did con-
siderable damage and were the cause of heavy losses in several sections.
The 1935 yields in the Monticello and adjacent areas were reduced 30 to
60 percent by the storm of September 2. There, also, were losses in Alachua
and Bradford counties, but they were much lighter.
Crotalaria spectabilis continues as a favorite summer cover crop with
many growers because of its reseeding ability and its value in soil building.
Crotalaria striata and C. intermedia are being used but not nearly as
extensively as C. spectabilis. Other commonly grown summer cover crops
continued to be planted in many orchards. A few growers have increased
the area in kudzu, both by planting new stock and from a natural spreading
of the vine growth from old plantings.
There is somewhat greater interest at present in winter legumes than
there has been for several years. No doubt this is due to the increased
nut yields obtained with these crops in experiments conducted by the
Experiment Station. Several growers are now making an effort to secure
seed of Augusta vetch (Vicia angustifolia) because of its ability to pro-
duce seed under Florida conditions and the fact that it will produce a
heavy tonnage of organic material to be returned to the soil.
In the eastern part of the state the trees generally held their foliage
better in 1935 than previously, and the spring of 1936 was more favorable







74 Florida Agricultural Experiment Station

than the year before. Therefore, there was a fairly good crop set this
year and the prospects now are better than for several years.
In the western section the crop is more or less spotted and apparently
is not quite as good as last year. The set on Stuart, however, is generally
heavier than for sometime and this should tend to even up the production.
Bloom and nut set in all parts of the state were in direct correlation
with condition of trees. In orchards where trees are thrifty and well fed
the trees have responded satisfactorily. Trees defoliated by the storm,
September 2, 1935, in the Monticello area, generally had a light bloom
this spring.
Zinc Treatments
In almost all instances badly rosetted trees responded in growth to
a greater degree during 1935 where 89% zinc sulfate, at the rate of two
pounds per tree, has been applied to the soil annually since 1933. Stuart
trees, 32 years old, are beginning to show marked improvement after two
annual applications of two pounds each and set a good crop of nuts this
spring.

COOPERATIVE FERTILIZER TESTS IN PECAN ORCHARDS
State Project 47 G. H. Blackmon
Work with fertilizers for pecans has been conducted along lines previ-
ously reported. Response of pecans to plant foods generally has been
more outstanding where large amounts of green material, produced by
leguminous cover crops, have been returned to the soil annually.
Growth: The growth of trees during 1935 was fair to good in all ex-
periments and in most instances was better in the fertilized than in the
unfertilized plots. Trees receiving additional nitrogen in the form of
sulfate of ammonia applied to the soil during July generally made more
growth than where the regular spring fertilizers only were applied.
Yield: Moore generally produced more nuts than any other variety
in the experiments, with Moneymaker second, and Curtis a close third.
Stuart failed in the experiment at Bonifay, but yielded fairly well at De-
Funiak Springs.
Where the first fertilizer applications were made in early spring there
was generally a response to sulfate of ammonia applied during July.
However, this has been more pronounced with the Moore trees set in 1919
than in any other experiment. With the Moneymaker and the older Moore
trees at Monticello there was not such a response. There were some dif-
ferences in favor of the sulfate of ammonia with Stuart and Success at
DeFuniak, but where the first fertilizers were applied in March the yields
were heavier than where all fertilizers were applied after the trees bloomed
and the crop set.
Where nitrogen alone was applied, tree yields generally have been
maintained. It should be pointed out, however, that all soi:s in the
nitrogen plots received complete fertilizer applications prior to 1932,
and possibly there continues to be a residual effect of phosphorus and
potash. All Moneymaker trees at Monticello shed a large part of their
crop during a six weeks drouth in June and early July of 1935, which
partially accounts for their low yield.
The prospects for a crop in 1936 are fair to good in all experiments
except in one Moore and Moneymaker orchard at Monticello, and the Money-
maker orchard at Tallahassee.






Annual Report, 1936


VARIETY AND STOCK TESTS OF PECAN, AND WALNUT TREES
State Project 48 G. H. Blackmon
There was a light crop produced in the pecan test orchard at Gaines-
ville in 1935. This was due partly to damage by cold in March 1935 and
to the September storm which blew off many nuts. Japanese and English
walnuts suffered much more from the cold than did the pecans.
The pecan trees made satisfactory growth during 1935 and in 1936
the more prolific varieties forced a heavy bloom and set a good crop of
nuts. The trees seem to be in good condition and are making an excellent
growth.
The application to the soil of two pounds per tree of 89% zinc sulfate
has continued to hold rosette in check and the pecan trees are making
almost normal growth. Black walnut seedlings, three years old, which
showed severe rosette responded almost 100 percent to soil applications of
one-fourth pound per tree of 89% zinc sulfate.
Pecan Oil: Following the preliminary tests in 1935 for extracting pecan
oil with pressure, additional work was done with nuts of the 1935 crop for
several varieties. Pecan oil has a clear, golden color and offers great
possibilities as a cooking and salad oil and for other uses.
A considerable quantity of pecan oil was expressed from the kernels
of several varieties of nuts of the 1935 crop. Frotscher, Kennedy, Curtis,
Moneymaker, Moore, and Stuart were the varieties used. By subjecting
the kernels to 12 tons pressure (cold) the oil expressed ranged from 25
to 36 percent of the kernel weight, except Frotscher which yielded only
13 percent.

PROPAGATING, PLANTING AND FERTILIZING TESTS WITH
TUNG-OIL TREES
Hatch Project 50 A. F. Camp and R. D. Dickey
The absence of freezing temperatures during and after the blooming
period, together with other favorable weather conditions, have been con-
tributing factors in tung oil growth and prospective heavy production for
1938. Consequently the tung oil plantings on the Station grounds set an
excellent crop of fruit this year.
The need for pure-line strains of high yielding varieties, and a satis-
factory commercial method of asexual propagation, is as great as ever.
With this in mind, a large number of cross- and close-pollinations of strains
having desired characteristics were made this spring.
Further trials were made on the propagation of tung oil by root grafts,
using the whip-graft method. Part of the root grafts were planted in
the nursery row immediately after being made, while the remainder were
placed under suitable conditions for callousing and planted later. Root
grafts made in early March 1934 were planted in the field under grove
conditions. Their growth has been poor and unthrifty when compared
with that of budded and seedling stock.
Since conditions sometimes exist which cause a shortage of selected
seed for planting, it is desirable to know how long seed will remain viable
in cold storage. Preliminary tests have been made on this problem and
further experiments are being initiated.
An experiment was started at Lamont to determine the effects of cover
crops and various amounts of nitrogen applied at different times on growth
and yield of tung-oil trees. The experiments at Lake City and LaCrosse
are being continued.







Florida Agricultural Experiment Station


TESTING OF NATIVE AND INTRODUCED SHRUBS AND
ORNAMENTALS AND METHODS FOR
THEIR PROPAGATION
Hatch Project 52 A. F. Camp and G. H. Blackmon
During the past season, cold injury to ornamental trees and shrubs
was much less severe than that of the previous winter. However, there
were instances in which some species and varieties showed more than nor-
mal injury. In most of these cases this injury could be directly attributed
to the fact that these plants had been injured the previous winter and
had not regained their normal vigor.
The following plant introductions have been under observation at Gaines-
ville for a sufficient time to warrant definite conclusions:
Cordia alba (FPI No. 89420) has made good growth on the Experiment
Station grounds. While well adapted to soil conditions of this area, it
has been killed to the ground by temperatures experienced in Gainesville
the past two winters, 16 F. and 23 F., respectively, and is therefore too
tender for use as an ornamental in this part of the state.
Sterospermum sp. (FPI No. 87495) has failed to withstand cold at
Gainesville; temperatures of 28* F. have killed it to the ground, but
in every case the plant has sprouted from the roots. It would not be
satisfactory where the temperature drops to 28* F. and lower.
Elaeagnus philippensis (SPI No. 64762) has shown by its thrifty growth
that it is well adapted to the soils of this area, but because of susceptibil-
ity to cold damage it is not satisfactory as an ornamental in the northern
part of the state.
Some 50 additional species of trees and shrubs have been planted in
the test grounds. Experiments are being conducted with these to determine
best methods of propagation.
Paper white narcissus experiments are under way to determine the
best types of slabs to plant for the production of saleable bulbs. Effect
of size of mother bulb upon size of slab and subsequent round bulbs pro-
duced will be noted.
Gladiolus varieties which are promising in other sections are being
tested for their value for growing under Florida conditions.
Apparently age of seed is a most important factor in germination of
seed of Ilex paraguariensis. A quantity of comparatively fresh seed was
divided into several lots, half of which were planted immediately and the
remainder held at room temperature for several months. At planting
time each lot of seed except one was treated with sulfuric acid of various
concentrations and for different lengths of time. The germination was
reasonably good with the fresh seed, regardless of the treatment, but
the old seed gave rather poor results when handled in the same manner.
Cuttings of Boehmeria sp. (FPI No. 105676) were made in October.
Semi-mature wood proved to be the best as a satisfactory percentage rooted,
but with the succulent stems only a small percentage forced roots and
grew.
COVER CROP TESTS IN PECAN ORCHARDS
State Project 80 G. H. Blackmon
A program which includes both winter and summer legumes, such as
hairy vetch and Crotalaria spectabilis, respectively, continued to give
good results with Frotscher during 1935 at Monticello. The heaviest nut
production was obtained in that part of the all-legume plots where sulfate
of ammonia is being applied during July of each year. In 1935 there






Annual Report, 1936


was not the difference in yield between plots in which winter legumes
were planted and where they were not, as in previous years. This probably
was due to the low yield for the previous several years in the summer
legume plot, which resulted in a resting period for the trees and a fol-
lowing heavy yield. Oats failed to prove satisfactory as a cover crop
and, therefore, are no longer included in the experiment. Data covering
the first seven years of the experiment were compiled and published in
Bulletin 297.
Augusta vetch (Vicia angustifolia) has shown great promise as a
winter cover crop since it makes satisfactory growth and continues to
produce an abundance of seed annually in many locations in north Florida.
A quantity of seed was harvested in the spring of 1936 for testing and
seed production under cultural conditions, since it has been impossible
to locate a commercial supply.
Green Material: The green weight of winter cover crops in the dif-
ferent plots was rather good for 1935-36. During the summer of 1935
there was not a good stand of Crotalaria spectabilis in some of the plots,
although in these there was considerable growth of native vegetation.
Growth: In Jefferson County the tree growth for Frotscher was best
where legumes were grown in winter and summer and sulfate of ammonia
was applied during July, while with Stuart and Moore there were only
slight differences in growth under different treatments.
Yield: Nut yield was materially reduced by the storm of September 2,
1935. The loss was calculated at 60% for Frotscher and Stuart, and
40% for Moore. Frotscher produced the heaviest yield in all treatments
except in one plot.
In the all-legume plots the 1936 bloom and subsequent set of nuts was
good for the Frotscher but light to fair for the Moore and Stuart, respec-
tively. Where summer legumes only are being grown there seems to be
a better set of nuts on the Stuart trees than with the other two varieties.

PHENOLOGICAL STUDIES ON TRUCK CROPS IN FLORIDA
State Project 110 F. S. Jamison
During the year over 150 varieties of vegetables have been grown in
an effort to find varieties or strains more suitable for production in Flor-
ida than the ones now being grown. Among varieties proving worthy of
special attention were Katahdin and Houma potatoes, California Wonder
pepper, Stringless Black Valentine beans, Glovel tomato, Klondike water-
melon and Straight-Eight cucumber. Four strains of peppers, developed
by the Connecticut Agricultural Experiment Station, appear well adapted
to Florida's growing conditions, although additional selection work is
necessary to fix the type of fruit before they are released for general
distribution. Selection work on African squash to isolate strains desir-
able for vegetable production was begun. Selection work was also con-
tinued with the Rocky Dew cantaloupe, a variety partially resistant to
mildew, in an attempt to develop a uniform strain producing high quality
melons. It was shown that lettuce seed could be satisfactorily grown at
Gainesville. This information will be of definite advantage in the lettuce
breeding program. Efforts to isolate a crisp, hard-headed lettuce for
Florida have been continued.
Perilla, planted March 23, began flowering during the last week of
June. Of the four strains planted, Perilla ocymoides has.made the great-
est growth, the plants attaining a height of over six feet before flowering.
Perilla nankinensis, purple red variety from Yokohama, reached a height







Florida Agricultural Experiment Station


of five and one-half feet before flowering. Seed of Perilla nankinensis,
green variety, failed to germinate.
A series of field treatments was initiated in which varying amounts
of lime and sulfur were added to the soil in an attempt to secure a-range
of soil reactions from very acid to alkaline. Lime was applied in amounts
varying from 200 to 4,000 pounds per acre. Sulfur was applied in amounts
of 50 to 600 pounds per acre. Soil acidity determinations were made at
intervals throughout the year to determine the effects of the various treat-
ments on the soil acidity. Tomatoes, eggplants, peppers and cucumbers
have been grown on the plots during 1936. When lime was applied
at the rate of 1,500 or more pounds an acre, it appeared to have a detri-
mental effect upon yield of tomatoes and cucumbers. Small quantities of
lime, 300 to 600 pounds per acre, stimulated production of cucumbers,:
but had little or no effect upon tomato yields. Yield of cucumbers was
decreased by the use of 300 pounds or more of sulfur per acre. Yield
of tomatoes was not significantly affected by applications of sulfur to
the soil. Harvesting of eggplants and peppers on these plots is not com-
pleted.
A number of crops used for green manure or cover crops by vegetable
growers of the state were planted in series during July 1935. Crotalaria
spectabilis, C. intermedia, cowpeas, Soja beans, velvet beans, and Sudan
grass were used. C. spectabilis plowed under when completely mature
gave the highest yield of dry matter per acre, while cowpeas gave the
lowest yield. The green manure crops were plowed into the soil in Novem-
ber and the land kept fallow until March. Green beans, tomatoes and
peppers were planted so that they grew on each of the green manure plots.
Yield of beans and set of early tomato fruits were greatly reduced by
dry weather that prevailed during the growing period. During the first
year beans gave greatest yields following Sudan grass and lowest follow-
ing a crop of volunteer weeds. Tomatoes produced greatest yield following
mature Crotalaria spectabilis and lowest following cowpeas. There was
considerable variation in yields between plots of the same treatment, a
large part of which can be accounted for by soil variations.
Soil moisture, acidity and organic matter are being measured on each
plot at regular intervals.

FUNDAMENTAL PHYSIOLOGY OF FRUIT PRODUCTION
State Project 111 A. F. Camp
Owing to time consumed in shifting work to the Citrus station, very
little was done on this project during the year. In the cultural plots
at Lake Wa'es, trees in mulched plots continued to show a better growth
and color with the practical disappearance of bronzing. Plots cultivated
were next best in appearance and non-cultivated plots were poorest. The
trees have largely recovered from cold damage of 1934, but the crop was
so irregular that no yield data were taken. The crop set for this year
is good and will yield definite results as to quantity and quality of fruit.

RELATION OF NITROGEN ABSORPTION TO FOOD STORAGE AND
GROWTH IN PECANS
C-
Adams Project 165 G. H. Blackmon and A. F. Camp
In a comparison of sand and Norfolk soil cultures, the percent of fixed
nitrogen in the whole seedlings, on a dry weight basis, was greater where
no boron was added for both sand and soil cultures. This was also true
for the different parts of the seedlings, except in the lateral roots from






Annual Report, 1936 79

the sand cultures. However, the amount of fixed nitrogen in the total
plant was more where boron was added because the seedlings made a
heavier growth.
Nitrogen determinations have been made of twigs from a number
of bearing pecan trees. Soils in which these trees are growing are being
fertilized with nitrogen from different sources and in one and two appli-
cat:ons. The work has not progressed far enough to justify a definite
report at this time.

VARIETY TESTS OF MINOR FRUITS AND ORNAMENTALS
State Project 187 A. F. Camp and H. S. Wolfe
Blackberries: "Boysenberry", a recently developed variety of black-
berry, has been added to the test plantings. The Advance blackberry
(both Strains 1 and 2), the Marvel blackberry and Youngberry produced
a satisfactory crop of fruit this season. The amount of marketable fruit
of the last two was reduced to some extent by the double-bloom disease.
The variety Mercereau bloomed but produced no marketable fruit.
Avocados: Mexican and hybrid Mexican varieties under test at Gaines-
ville were again subjected to freezing temperatures this past winter. The
lowest recorded temperature was 23 F. the night of December 21. Injury
was much less severe than that recorded for the previous winter. No
trees in this planting recovered to the extent that a heavy bloom was
produced. Propagation of the three trees having the most desirabe char-
acters as to size, flavor and time of ripening of fruit is being continued.
Grapes: As a result of the loss of almost all of the original planting,
the grape block was replanted in 1934, using only the Florida Beacon. The
pruning experiment has been continued as outlined.
Pears: Three varieties of the Chinese or Sand pear-Johnson, Harper
and Baldwin-have been added to the planting, which consists of varieties
of the Chinese or Sand pear, the common pear, and hybrids of the two. These
are under observation to determine their adaptability, blight-resistance and
desirability from the standpoint of yield and quality of fruit.
Work has been started to determine if it is possible to establish a
nematode-resistant peach stock in Florida. Propagation wood of eight
promising varieties was secured from the California Experiment Station
and budded on peach seedlings. These will be planted in locations where
the soils are only lightly infested with nematodes for the production of
seed with which the tests can be continued.

STUDY ON THE PRESERVATION OF CITRUS JUICES AND PULPS
State Project 189 A. F. Camp and A. L. Stahl
The study of cool storing orange juice, without actually freezing it,
for periods up to two weeks, was continued. The best juice obtained,
which could not be distinguished from fresh juice after 10 days' storage,
was prepared by sterilization of all equipment, extracting pre-cooled, peeled
fruits on a cup press, immediately vacuumizing, relieving vacuum with
carbon dioxide gas, bubbling carbon dioxide gas through the juice for
10 minutes before bottling in half-pint milk bottles, and storing at 32 F.
The slight carbonation tends to cover up any storage tastes which may
develop, yet leaves no carbonation effect. Storage at 32 F. was found
to be most favorable. Nitrogen gas used in place of the carbon dioxide
also gave good results. It gave the juice a fruity flavor which covered
up the stored flavor. The method giving the best results as described
above is now being used commercially.







Florida Agricultural Experiment Station


The combination of half orange juice and half tangerine juice not only
gave the juice a more desirable orange color, but also a delicious blend
in flavor. Small amounts of peel-oil were found objectionable.
Quick-frozen juice made from mature oranges and tangerines, which
had no pre-treatments or additions, was found to have the flavor of fresh
juice after three years' storage in glass under vacuum at 0 F. After
three years' storage at 0 F., juice made from immature oranges retained
its bitter flavor in the same degree as at the beginning.
Quick-frozen strawberries and Youngberries in 40, 50 and 60 percent
sugar solutions were in perfect condition and had the flavor of fresh fruit
after four years' storage in glass under vacuum at 0 F. When waxed
cardboard containers were used in place of glass, the drying out was
excessive and the juice took on a musty taste from the paper, but when
they were wrapped in cellophane frozen berries kept splendidly for three
years with very little drying and loss of flavor.

COLD STORAGE STUDIES OF CITRUS FRUITS
Purnell Project 190 A. L. Stahl and A. F. Camp
Research under this project was continued along lines previously
reported. It was expanded also to include more citrus types, varieties
and problems. Previous results with still-air storage, moisture-proof wrap-
pers and a number of surface coverings were verified during the past year.
Investigations under way to control stem-end rot and Penicillium mold,
the two most important citrus storage decays, produced important develop-
ments. A large amount of fruit was cold-stored, wrapped in wraps im-
pregnated with iodine, copper sulfate, etc. Copper sulfate wrappers had
no beneficial effect, while iodine wrappers were found to reduce both
decays materially. Iodine-impregnated paper wraps, when used with
aluminum foil or other moisture-proof coverings, were found to be most
efficient in controlling stem-end rot. Iodine, 95% alcohol (both ethyl and
methyl), salicylic acid, turpentine and benzoic acid, when applied to the
button directly after picking and then sealed with shellac, caused material
reduction in amount of stem-end rot during and after removal from storage
in both oranges and grapefruit. Borax dips of different concentrations
and temperatures proved of no value in controlling stem-end rot, but did
reduce Penicillium mold in stored citrus. Fungicides were added to the
several commercial surface coverings before applying to the fruit and
the most outstanding of these was iodine.
In refrigeration research, a great deal of work has been done during
the last few years covering the effects of temperatures, humidities, wrap-
pers, treatments, chemical composition, gases and, to some extent, cultural
treatments. Those phases which have been completed have been submitted
for publication in bulletin form.

MATURITY STUDIES OF CITRUS FRUITS
Purnell Project 237 A. L. Stahl
A. systematic study of citrus fruits from bloom to maturity has been
made, from which methods for determining ripeness or maturity may be
developed. During the past season thousands of fruits were sampled and
analyzed at regular intervals. Commercial varieties of oranges and grape-
fruit were sampled from five different sections of the state. These data
will be compared with those for the previous season to determine effects
of weather conditions on various characteristics of the fruit. Effects of






Annual Report, 1936


various cultural and chemical treatments on the development of the fruit
from bloom to maturity are being studied also.
Histological studies of the development of the orange and grapefruit from
fruit-bud formation to maturity have been made. Thousands of micro-
slides have been made of the different tissues of several types of citrus,
such as albedo, flavedo, locular walls, core, juice sacs, vascular bundles,
oil glands, etc. These are being considered individually as to their origin
and development.
Quantitative measurements of the chlorophyll, carotin and xanthophyll
content of the rind have been made of the orange. The chlorophyll con-
tent decreased, while the other two increased only slightly with maturity.
Correlating color of the orange with its physical and chemical char-
acteristics, it was found from the analyses of several thousand oranges
that the specific gravity of the fruit and juice and percent sugars increases
with increase in color (deeper shade of orange). The percent acid remains
practically the same, but does show a slight increase.

STUDIES ON THE EFFECT OF ZINC AND OTHER UNUSUAL
MINERAL SUPPLEMENTS ON THE GROWTH OF
HORTICULTURAL CROPS
Purnell Project 238 A. F. Camp
Citrus Trees: The research of the past three years conducted under
this project has resulted in the widespread use of zinc sulfate as a correc-
tive for frenching of citrus in all the major producing areas of the state.
The fact that practically all agricultural supply houses serving the citrus
industry now stock a supply of this material, whereas three years ago
they did not stock a single sack, indicates the prominent position the
physiological trouble known as frenching occupies in citrus problems.
During the past two years a number of zinc materials have been com-
pared to the standard zinc-lime mixture for frenching control. Among
these, zinc oxide gives promise, from a commercial standpoint, of being
a good substitute for zinc sulfate. Test plots show that zinc oxide at the
rate of 2 pounds to 100 gallons of water will control frenching as effectively
as the standard 2/2-114-100 zinc sulfate-lime formula now tentatively
recommended. However, zinc oxide has a disadvantage in that it will burn
newly set fruit under certain conditions. The standard zinc sulfate-lime
mixture has a disadvantage in that it tends to induce a scale infestation
subsequent to its application to the foliage. There is some indication that
the zinc oxide spray has less tendency to produce this effect. This matter
is being given considerable study at the present time.
There has been some controversy regarding the effect of zinc treatment
on ammoniation of fruit. A block of citrus was selected having both severe
frenching and severe ammoniation of fruit. Plots were laid out to compare
a variety of copper and zinc soil and spray treatments, and also combina-
tion treatments of zinc and copper. The results obtained were quite
clear-cut.
In every plot where zinc spray treatments alone were applied, good
control of frenching resulted, but an abundance of ammoniated fruit was
to be found. Every plot receiving copper alone in the form of either
spray or soil treatment showed an abundance of frenched foliage, but good
control of ammoniation. Combination spray treatments of zinc and copper
resulted in good control of both disorders. These results confirm work
previously reported.
Tung-Oil Trees: Many extensive experimental plots are being main-
tained on a long time-basis for the value of the accumulated data. This






82 Florida Agricultural Experiment Station

phase of the work is being carried over a period of years to secure re-
liable information on which to base recommendations for a far-reaching
zinc amendment program. In addition, two large-scale plot systems have
been laid out in commercial tung-oil plantings to test zinc oxide as a
substitute for zinc sulfate.
Comparative chemical analyses of healthy and diseased tissues are being
made in an attempt to gain some knowledge of the physiological basis of
bronzing of tung-oil trees.

SPECTROGRAPHIC STUDIES OF THE COMPOSITION OF TISSUES
AND CORRESPONDING SOILS OF NORMAL AND PHYSIO-
LOGICALLY DISEASED HORTICULTURAL CROPS
Purnell Project 266 L. W. Gaddum, A. F. Camp
and Walter Reuther
During the six months since the inauguration of this project a fairly
comprehensive set of samples of citrus and tung were collected and pre-
pared for analysis. Quantitative zinc analyses have been completed on
most of the foliage samples.
Tables 3 and 4, presented herewith, give some indication of the type
of results so far obtained.
Results to date show a high degree of correlation between foliage
condition and zinc content not only in the physiological trouble of tung
known as bronzing, but also in a parallel disease of citrus known as
frenching. Further, these data show that zinc treatment of diseased trees
by means of soil applications of zinc sulfate increases the zinc content
of the foliage thereon.
In the case of citrus, normal foliage and frenched foliage samples
were selected from the same tree. In general, the zinc content of apparently
normal foliage from trees having considerable frenched foliage is lower
than in normal foliage samples from trees having little or no frenched
foliage.
These results tend to give support to the theory that zinc is a neces-
sary element for normal growth of citrus and tung.

FUMIGATION RESEARCH
R. J. Wilmot

The HCN gas analysis instrument described in the 1935 Annual Report
was brought to its finished state in portable form. It was made portable
by installing a 6-volt motor-driven blower which would maintain a flow
of % liter per minute through the gas analysis cell, using a 24-foot
sampling tube.
The whole unit, exclusive of the storage battery, is built into a box
9%x12x8% inches and weighs approximately 18 pounds.
Continuing the work on Lasioderma serricorne (Fab.) it was found
that two-day old beetles were most resistant to hydrocyanic acid gas and
that a four-hour exposure at 30* C. with a concentration of .4% HCN
killed only 92% of the two-day beetles.







TABLE 3.-COMPARATIVE ZINC CONTENT OF NORMAL, DISEASED AND ZINC TREATED TUNG FOLIAGE (Aleurites Fordii), AS
DETERMINED BY SPECTROGRAPHIC ANALYSES.


Notes: Samples 40 R and 41 R consist of selected bronzed leaves from areas where severe bronzing was prevalent.
Samples 42 R and 43 R consist of selected normal leaves from areas where bronzing was almost non-existent.
Samples 44 R and 45 R consist of random collection of leaves from areas previously bronzed, but subsequently
treated with soil applications of zinc su'fate.
All samples are composite of approximately 36 trees, and sufficient leaves were collected to make a sample
having a green weight from 11 to 2 pounds.


Description _Analyses of Leaves I Analyses of Petioles
Sample Zinc in ppm| % Zinc in ppm Zinc in ppm % Zinc in ppm
No. Source Condition Treatment Dry Basis Ash Ash Basis I Dry Basis Ash Ash Basis

40 R Brooker, Fla. Bronzed No zinc 6.2 10.4 58 3.7 9.6 39

I 'I I
41 R Brooker, Fla. Bronzed No zinc 3.6 9.8 37 4.0 11.5 35

42 R Brooker, Fla. Normal No zinc 35.8 12.8 280 28.4 10.5 270

43 R Brooker, Fla. Normal No zinc 16.4 11.7 140 9.1 10.7 85

44 R Brooker, Fla. Normal Zinc treated 15.7 11.2 140 10.7 11.4 94

45 R Brooker, Fla. Normal Zinc treated 22.9 10.4 220 14.4 10.3 140








TABLE 4.-COMPARATIVE ZINC CONTENT OF NORMAL AND FRENCHED CITRUS FOLIAGE, AS DETERMINED BY SPECTROGRAPHIC
ANALYSES.
I Analyses of Twigs
SDescription Analyses of Leaves I + Petioles Remarks
Sample i Treat- Zinc-ppm % Ash Zinc-ppm Zinc-ppm % Ash Zinc-ppm mark
No. Variety Source I Condition I ment IDry Basis Dry BasislAsh Basis Dry Basis Dry BasislAsh Basisl_
I I Z
46 R Pineapple Umatilla Normal No Zinc 16.0 14.2 113 21.4 12.4 173 Samples selected 3.
48 R Pineapple Umatilla Frenched No Zinc 5.2 13.1 40 5.8 9.0 65 from same tree.

49 R Marsh Grf. Umatilla Frenched No Zinc 3.8 12.8 30 5.4 9.8 55 Samples selected
50 R Marsh Grf. Umatilla Normal No Zinc 9.9 14.1 70 27.1 12.9 210 from same tree.

52 R Marsh Grf. Umatilla Normal No Zinc 25.3 17.1 148 15.8 15.5 102 Tree has little
I l wrenching.
53 R Valencia Vero Beach Frenhed No Zinc 11.7 22.6 52 9.3 15.8 59 Samples selected
54 R Valencia Vero Beach Normal No Zinc 12.6 21.0 60 14.0 15.6 90 from same tree.

55 R Valencia Vero Beach Normal Zinc to 29.1 18.8 1 55 22.4 14.0 160 Tree previously
I ______ Soil drenched.

56 R Valencia Vero Beach Normal No Zinc 47.3 16.9 280 21.0 13.1 160 Normal tree in
S normal area.

67 R Lue Gim Gong Near Davie Normal No Zinc 13.3 19.0 70 7.4 12.4 60 Normal tree in
Normal area.

68 R Lue Gim Gong Near Davie Frenched No Zinc 5.8 14.5 40 5.1 10.2 50 Samples selected
69 R Lue Gim Gong Near Davie Normal No Zinc 7.8 15.6 50 5.4 10.7 50 from same tree.
Notes: Samples from Umatilla from a grove on "high pine" soil (Norfolk series).
Samples from Vero Beach from a grove on low hammock soil with marl subsoil (Parkwood series).
Samples from the grove near Davie are from trees growing in the Everglades peat or muck soil.






Annual Report, 1986


PLANT PATHOLOGY

Work on a few plant disease projects was handicapped by unfavorable
weather conditions but on the whole the work progressed satisfactorily.
The sulfur-lime treatment of soil for the control of brown rot of
potatoes was used successfully this year on a small commercial scale.
Investigations of melanose and scab of citrus have reached the stage that
rather definite measures of control for many sections can now be recom-
mended. Because new fungicides are appearing every year, spraying
experiments will probably be continued on a sufficient scale to test their
comparative efficiency.
Two plant diseases, pink rot of celery at Sarasota and rust of beans
on the lower East Coast, were unusually destructive during the winter
and early spring months. Since both of these diseases occur to some extent
every year in the respective localities, it appears probable that the epiphy-
totics were due to prevailing weather conditions that were unfavorable
for the crop plants and favorable for the parasites. A wide number of
other diseases besides the ones under investigation have been very prevalent
and destructive this year and numerous calls have been made upon mem-
bers of the staff at Gainesville and the field laboratories for advice in
combatting them.
During the past five years there has been a rapid and steadily increas-
ing interest in the identification of wild plants. Specimens sent in for
identification included miscellaneous plants of the sender's locality, medi-
cinal or drug plants, weeds, forage plants, poisonous plants, aquatics and
plants influencing the propagation of mosquitoes.

DOWNY MILDEW OF CUCURBITS
Adams Project 19 G. F. Weber
Active field work on this project was concluded at the end of the previ-
ous season. In September 1935 the first wild host, Melothria crassifolia
Small, native to Florida, was found affected with downy mildew, Perono-
plasmopara cubensis (B. & C.) Clint. In controlled inoculation experiments
with spores from the wild host the typical disease was produced on cu-
cumbers.

INVESTIGATIONS RELATIVE TO CERTAIN DISEASES OF
STRAWBERRIES OF IMPORTANCE IN FLORIDA
State Project 126 A. N. Brooks, Plant City
For three consecutive seasons strawberry plants have been set at regular
intervals during the fall, from September to November, in an attempt to
determine what effect time of setting might have upon development of
diseases. There were no differences in disease development on early and
late set plants, but in general plants set during September were more
vigorous and produced more fruit than did those set later.

STUDIES RELATIVE TO DISEASE CONTROL OF WHITE
(IRISH) POTATOES
State Project 130 A. H. Eddins, Hastings
RHIZOCTONIA
Spaulding Rose seed treated with 1:129 ethylene chlorhydrin and seed
exposed to temperatures of 82* to 90* F. in an incubator and 48" to 64 F.
in the laboratory for 12 days prior to planting germinated rapidly and






Florida Agricultural Experiment Station


at the end of five weeks had produced large. plants with stands of 96
to 98 percent. Seed exposed to temperatures of 34 to 39 F. and 29
to 69" F. for 12 days germinated more slowly and produced much smaller
plants; percentages of seedlings emerged from the soil at the end of five
weeks were 63.8 and 92.0 percent, respectively. Smallest percentages of
plants with symptoms of rhizoctonia were produced by seed given the
ethylene chlorhydrin treatment and that exposed to temperatures of 82"
to 90. F. However, seed exposed to temperatures of 34 to 39* F. and
29 to 69" F. produced best yields, as the seedlings were smaller and less
severely damaged by a frost which occurred 40 days after planting.
SCLEROTINIA ROT
Low temperatures during January, February and early March and
clear dry weather during April were unfavorable for sclerotinia rot in
1936 and less than 5 percent of the plants were affected with this disease
in fields where over 50 percent had been killed in 1935, when conditions
were more favorable for the disease. No information was obtained on
effectiveness of applications of various fungicides in controlling sclerotinia
rot, as only a trace of the disease appeared in the experimental field.
However, late blight was present and red copper oxide gave better control
of this disease than 4-4-50 bordeaux mixture, 1:30 lime-sulfur, 20-80
copper-lime dust or kolodust.

INVESTIGATION AND CONTROL OF BROWN ROT OF POTATOES
AND CLOSELY RELATED PLANTS CAUSED BY
Bacterium solanacearum E. F. S.
State Project 143 A. H. Eddins, Hastings
Application of 800 pounds of inoculated sulfur per acre in June 1934,
followed by 3,000 pounds of dolomitic limestone per acre in November of
the same year, materially reduced bacterial wilt in tomatoes and eggplants
grown in this soil in the summer of 1935. Tomatoes in treated soil yielded
1.1 pounds of marketable fruit per plant with 17.9 percent of the plants
killed, while the yield on non-treated soil was 0.1 pounds of fruit per plant
with 98.8 percent of the plants killed. Eggplants in treated soil yielded
5.2 pounds of marketable fruit per plant with 5.9 percent of the plants
killed, while the yield on non-treated soil was only 0.4 pounds per plant
with 70.6 percent killed.
March and April temperatures in 1936 at Hastings were only slightly
above normal and brown rot caused an estimated loss of 2 percent of the
potato crop as compared with a loss of 8 percent in 1935 when the March
and April temperatures were much higher.
Sulfur-limestone soil treatment gave excellent control of brown rot of
potatoes in 1936. Increase in yield of healthy marketable tubers at West
Tocoi in Scranton fine sand treated with 800 pounds of sulfur per acre
in June 1934, followed by 3,000 pounds of limestone per acre in November
1934, was 15.5 barrels per acre. Brown rot tuber infection was 0.7 percent
in treated soil and 11.3 percent in non-treated. At Hastings the increase
in yield produced in Bladen fine sandy loam soil, which was given the
sulfur-limestone treatment in 1935, was 16.3 barrels of healthy marketable
tubers per acre; tuber infection in treated soil was 0.6 percent and in
non-treated 21.9 percent.
The sulfur-limestone treatment also caused significant increases of 9.4
barrels of healthy tubers at West Tocoi and 6.3 barrels per acre at
Hastings in 1936, when the disease appeared late and had little effect in
reducing yields. Furthermore, corn planted in April in treated plots at






Annual Report, 1936 87

both places has grown much better than corn in adjacent non-treated plots.
These observations indicate that profitable increases in yields of potatoes,
corn and other crops might be obtained in soils which are not infested
with B. solanacearum as well as in those which are infested by giving
them the sulfur-limestone treatment.
Tests conducted in June 1936 showed that commercial uninoculated
flour sulfur, when applied to Scranton fine sand at the same rate per acre
as inoculated sulfur, produced soil reactions lethal to B. solanacearum.

INVESTIGATIONS OF SEEDLING, STALK AND EAR ROT DISEASES
OF CORN CAUSED BY Diplodia SPP.
Purnell Project 146 R. K. Voorhees
This project was inactive for the year because of pressing activities
of- other projects.
INVESTIGATIONS OF DISEASES OF FERNS AND ORNAMENTALS
State Project 148 W. B. Shippy, Leesburg
Thirty-six rose varieties were compared for vigor, susceptibility to
black spot and other foliage injuries, and amount of die-back of canes.
Outstanding in growth and disease resistance were Louis Philippe, Mme.
Lombard, Radiance, Marie Van Houtte, Frances Kruger, Duchesse de
Brabant, Etoile de Hollande, Etoile de France, Jonkheer J. L. Mock and
Maman Cochet.

INVESTIGATION OF AND CONTROL OF FUSARIUM WILT, A
FUNGOUS DISEASE OF WATERMELONS CAUSED
BY Fusarium niveum
State Project 150 M. N. Walker, Leesburg
Results of 1935 experimental plantings were very satisfactory, and
629 melons were harvested for seed. Of this number a large proportion
was of Strain 61, which has shown up well in wilt trials since 1932 and
has been described under the name "Leesburg". The remainder was from
a number of strains showing some promise from one or more standpoints.
A rigorous selection was made in harvesting and further selections were
made the following winter on a basis of quality of melon, reaction to wilt
in the field and seedling trials in the greenhouse. By this process, 395
individual melon selections were discarded. Of the 194 strains retained,
128 were of Strain 61. Forty of these strains were bulked with portions
of 56 others of the same stock for distribution to growers for trial. Four-
teen pounds of selfed seed were thus obtained and were distributed in
small samples, ranging from four ounces to two pounds, under the variety
name of Leesburg. Also, small samples of seed of a number of individual
melon strains were sent to eight experiment stations for trial.
Direct reports have been received from but few growers to whom seed
was sent. One very favorable report has been received from a Florida
seed house in which it was stated that on land where melons failed last
year because of wilt, no vines had been observed to die this year. A few
other favorable reports have been received, although the trials were not
under as severe conditions as the one mentioned above.
One hundred fifty-four lots of seed from individual melons were
planted in the experimental field in 1936. Of this number 97 were of
Strain 61, These seed were planted early in March, but unfavorable
weather conditions with unprecedented infestations of mice and cutworms







88 Florida Agricultural Experiment Station

reduced the stand considerably, and since sufficient reserve seed of all
strains were not available for replanting, a comparatively small number of
plants of certain strains was grown. However, seed from 77 melons
grown to maturity in the greenhouse were available for filling in some
of the blank areas early in April. The 1936 growing season has been
a difficult one, but temperatures favorable to wilt have obtained through-
out, which, of course, is an advantage in evaluating resistance of various
seed lots. This year the first hill in each section of the field was planted
with seed of the commercial Watson variety. There were thus planted
302 hills, approximately 1,500 plants. None of these plants were thinned
out, and at present, June 10, scarcely a plant of this variety remains in
the field. On the other hand, a considerable number of selected strains
have shown almost entire freedom from wilt. The Leesburg has shown a
higher percentage of resistance this year than that given for it in Bulle-
tin 288.
During the season of 1936, 5,100 artificial pollinations have been made
and, unless unforeseen difficulties arise, 750 to 800 melons will be obtained.
INVESTIGATION OF AND CONTROL OF FUNGOUS DISEASES
OF WATERMELONS
State Project 151 M. N. Walker, Leesburg
Work on this project, as in the past, has been restricted to observations
of general disease conditions in commercial fields as well as in the experi-
mental field and dusting for their control in the experimental field.
The season of 1936 has been generally unfavorable to the watermelon
crop. The weather early in the season was very cool and wet. During
this period the most severe infection of Mycosphaerella blight that has
been observed appeared in large plantings in the vicinity of Groveland.
Entire plantings were killed, necessitating replanting four or five times.
Several growers of long experience reported that they had never seen
comparable injuries. Dusting with 20-80 copper-lime dust appeared bene-
ficial, but an improvement in weather conditions seemed even more effective
in checking the disease and later observations showed that the disease
had almost entirely disappeared. At this time, however, downy mildew
was very abundant in all fields visited, but did not appear to be causing
great injury.
A new disease was observed in a commercial field of the variety Cuban
Queen. The trouble strongly resembled an early anthracnose infection, but
it was restricted entirely to the melons, the leaves being unaffected. Of
three varieties in the field only the Cuban Queen showed the injury. Cul-
tures showed no fungous growth and it appears probable that the injuries
were caused by some insect or were due to an inherent weakness of the
variety.
A STUDY OF THE SO-CALLED "RUST" OF Asparagus plumosus
State Project 167 W. B. Shippy, Leesburg
To determine whether or not soil moisture and light intensity have
any effect upon the development of rust, plants were grown in pots of
soil with moisture content ranging from 2 to 27 percent and under light
intensities varying from that provided by one layer of cheesecloth to the
deep shade of a muslin cover. Moisture determinations of mature fern
sprays grown under different conditions showed that the water content
was about the same, averaging about 58 percent. This indicates that
the asparagus fern is well equipped to maintain a moisture balance during
periods of drought; further tests will be necessary under improved experi-
mental conditions before conclusions may be drawn.






Annual Report, 1936


Determinations were made of soil reactions in 13 ferneries to determine
the relation between growth of plants and hydrogen-ion concentration of
the soil. The survey showed that the average reaction for these ferneries
ranged from pH 4.14 to 6.17 and that soil of the best producing ferneries
was generally most acid. However, these ferneries had received larger
applications of high grade fertilizers and it is probable that the better
growth was due to this difference rather than to more favorable soil re-
action. Tests have been initiated to determine the optimum pH for plu-
mosus as well as the range of tolerance.

CONTROL OF WILT OF TOMATO, Fusarium lycopersici Sacc.
IN FLORIDA
Hatch Project 180 G. F. Weber and D. G. A. Kelbert, Bradenton
During the previous season seed were collected from individual resist-
ant tomato plants of the F, generation growing on wilt-infested soil in
Manatee County and from the fruits resulting from crosses made at the
Main Station. Plants from these seed were grown at Gainesville during
the fall (July-November) on disease-free soil for seed increase. These
lots of seed supplemented by 15 commercial varieties were planted on
two acres of infested soil in Manatee County during the season of 1936.
This planting contained plants of the F,, F, and F2 generations as well
as a number of back-crosses of some most promising hybrids. In these
trials all susceptible check plants were killed by wilt. A number of hybrids
also were eliminated because of their susceptibility to wilt, while certain
other hybrids showed exceptional qualities and withstood the disease in
a very promising manner. Individual plants were selected from the most
promising strains and seed were collected from them during May and June
preparatory to planting at Gainesville this fall to increase the population
for trials in Manatee County next year. In addition, 600 blossoms were
worked during the spring at Gainesville, involving 50 new crosses. The
seed have been collected and they will be planted this fall for seed increase.

CLITOCYBE MUSHROOM ROOT ROT OF CITRUS AND OTHER
WOODY PLANTS IN FLORIDA
State Project 181 A. S. Rhoads, Cocoa
During the year Clitocybe tabescens (Scop.) Bres. has been isolated
from roots of the following plants attacked by mushroom root rot: acalypha
(Acalypha marginata), Australian pine (Casuarina cunninghamiana and
C. lepidophloia), blue leadwort (Plumbago capensis), calamondin on rough
lemon (Citrus limonia) stock, camphor (Cinnamomum camphora), Con-
federate jasmine (Jasminum pubescens), pink ball (Assonia wallichi),
Dr. Van Fleet and Paul Neyron roses on Rosa multiflora stock, rubber
vine (Cryptostegia madagascariensis), Surinam cherry (Eugenia uniflora),
and thunbergia (Thunbergia grandiflora var. alba).
The disease was also found attacking the following plants during the
year: Australian pine (Casuarina equisetifolia, C. glauca, C. montana
and C. stricta), azalea (Azalea indica), biota (Thuja orientalis), Brazilian
pepper (Schinus terebinthifolius), cape jasmine (Gardenia florida), cassia
(Cass'a sieberiana), cypress pine (Callistris robusta); grapefruit and
Valencia orange on rough lemon (Citrus limonia) stock, Italian cypress
(Cupressus sempervirens), laurel oak (Quercus laurifolia), Duchesse de
Brabant, Etoile de France, Francis Scott Key, Lady Hillingdon and Radi-
ance roses on Rosa multiflora stock, turkey oak (Quercus catesbaci), weep-







90 Florida Agricultural Experiment Station

ing laurel (Ficus benjamini, wild cherry (Padus serotina), and Xylophilla
elongata. This is the first time that Clitocybe mushroom root rot has been
found attacking several of these plants, which brings the known host
list up to 110 different species of plants in Florida.
A survey of a 25 year-old grove at Kathleen, Polk County, where
Clitocybe root rot has occurred frequently since 1915, showed this disease
to be prevalent in a 10-acre block of orange and grapefruit trees on a
mixture of rough and everbearing lemon rootstocks, and also in a smaller
block of grapefruit trees on rough lemon rootstock, while an adjoining
small block of grapefruit trees on grapefruit stock has remained free
from the disease. Striking differences indicate a marked resistance of
the grapefruit rootstock under conditions where the rough and everbearing
lemon rootstocks have, as is the general rule, proved very susceptible.
Clitocybe root rot has been observed to attack sweet seedling orange trees
and one seedling grapefruit tree, but no definite case has been observed
as yet of trees on sour orange stock being attacked, even in groves where
the disease caused an extremely heavy mortality of Australian pine
(Casuarina equisetifolia) trees in windbreaks planted around and through
the groves.
It has been demonstrated that prized ornamental specimens of Austra-
lian pine (Casuarina lepidophloia) and some other trees that have been
almost completely girdled by the mycelium of the Clitocybe root rot fungus
can be saved by careful surgical treatment followed by banking with soil
to induce the development of a new root system.

CONTROL OF BLACK SPOT (Phoma destructive Plowr.) OF TOMATOES
IN FLORIDA AND IN TRANSIT
Hatch Project 182 W. B. Tisdale and Stacy Hawkins
Experiments for the control of phoma spot of tomato were initiated
in the 1935-36 season with the early or pineland crop in the Homestead
area. These experiments were conducted in two fields, one at the Sub-
tropical Station and the other in cooperation with a grower. Hurricanes,
drouth and frost damaged plants in the plots to such an extent that re-
liable data could not be obtained.
Experimental work on this project has been completed.

A STUDY OF STRAWBERRY WILT OR CROWN ROT
State Project 184 A. N. Brooks, Plant City
Experiments were conducted again in a strawberry nursery heavily
infected with runner spot or anthracnose to make a comparative test of
effectiveness of three spray materials in its control. Twelve plots of one-
fifth acre each were sprayed at weekly intervals, beginning the first week
in July and continuing through the second week of September. Four plots
were sprayed with 4-6-50 bordeaux plus a compound of sodium oleyl sulfate
1:2,000; four with a proprietary mixture composed of 15 percent copper
resinate plus emulsified pine oil 1:100; and four with sodium polysulphide
1:200 plus 1 pounds soap to 50 gallons spray. No unsprayed plots were
left for checks, the object being merely to test the relative values of the
three spray materials as fungicides. Results were obtained by actual
counts of plants.' Total number of plants from the plots sprayed with
bordeaux and those sprayed with the copper resinate mixture was about
the same, whereas the number from the sodium polysulphide plots was con-
siderably less.
Active work on this project has been completed.







Annual Report, 1936


CERTAIN STUDIES OF DECAYS OF CITRUS FRUITS IN STORAGE
Adams Project 193 W. B. Tisdale and Erdman West
Several chemicals not tested previously were used in aqueous solutions
or suspensions for washing 3,700 oranges of three varieties to determine
their effectiveness in preventing stem-end decay and molds. In each test,
one lot of fruit was treated with 8 percent borax and another with sodium
thiuram sulfate for comparison with other materials used. Sodium thiuram
sulfate proved a little more effective in every test than borax, while no other
material used was as effective as either of these. Some of these materials
were followed by or used in combination with a coating agent for reducing
moisture loss. It was again apparent that any coating agent that prevents
loss of moisture from the fruit increases the percentage of rot, regardless
of whether or not a disinfectant had been applied before the coating agent
or included in it. This indicates that the amount of moisture in the button
and rind influence the development of stem-end rot during the storage
period.

A STUDY OF THE SPRAYING REQUIREMENTS NECESSARY TO
CONTROL GRAPE DISEASES IN FLORIDA
State Project 196 K. W. Loucks, Leesburg
This project closed with the publication of Bulletin 294.

INVESTIGATIONS OF A BARK DISEASE OF TAHITI LIME TREES
Adams Project 242 W. B. Tisdale
A considerable acreage of groves was planted to Tahiti limes and
Perrine lemons this year, many plantings being made during March and
April. Prevailing dry weather and strong winds were unfavorable to
late plantings and a high percentage of the trees dried out at the cut
end and became infected, resulting in death of several inches of the stems
or completely to the bud union. Isolations were made from many such
trees and Phomopsis and what appears to be a species of Colletotrichum
were obtained in a majority of cases. Isolations were also made from
older trees injured by cold and wind and Diplodia was obtained from most
larger limbs and trunks and Phomopsis from the smaller branches. Inocu-
lations are being made with the various organisms and their morphological
characters are being studied to determine the identity of the parasitic ones.
This year work was started in cooperation with the Citrus Experiment
Station to study effects of various treatments of lime trees before setting
them in grove formation upon infection of the cut ends of trunks. For
this purpose 160 trees of the usual size for transplanting were divided
into eight lots of 20 each and set on the Citrus Station plots on February
10. Lot 1 was transplanted without cutting back or removing any of the
foliage and the trunks of those in Lot 2 were cut back to approximately
.18 inches and the thorns removed, according to usual nursery practice,
but no other treatment was applied. Lot 3 was cut back and the cut
ends were coated with a commercial wound dressing. The other five lots
were cut back in the usual manner and the stems were immersed momen-
tarily up to the bud union in the following suspensions: Lot 4, 4-4-50
bordeaux plus 2 percent oil; Lot 5, an organic mercury in oil emulsion
1:30; Lot 6, liquid lime-sulfur 1:20 plus 10 pounds wettable sulfur per
100 gallons; Lot 7, red copper oxide one pound to 50 gallons water plus
0.5 percent cottonseed oil emulsion; and Lot 8, 4-4-50 bordeaux plus 10
pounds wettable sulfur per 100 gallons.






Florida Agricultural Experiment Station


All lots of trees were set in the grove the same day they were removed
from the nursery, and were watered thoroughly. Trees in Lot 1 had
young growth when transplanted and the tips of most young shoots died
back and the plants were slow in starting new growth subsequently. After
four months only four of them showed any trunk infection. This originated
in injuries resulting from transplanting operations. None of the other
treatments appeared to have retarded development of new growth, as
all lots of trees started vigorous shoots promptly. However, there were
variations in the reaction of the cut ends to the different treatments. All
trees of Lot 3 treated with the wound dressing, except three, showed signs
of dying back from the cut ends within a few weeks and at the end of
two months several of them died back a distance of five inches. All plants
were cut back at this time below the dead parts and the cut ends were
painted with shellac followed by white lead paint. Within two weeks all
trees showed injury from this treatment. At this time Lots 8 and 4,
respectively, showed the next greatest amounts of this kind of injury,
while the others were about the same as Lot 2 which received no treatment.
About one-fourth of the trees in these lots showed dying back but this
was not extensive. Two months later, four months after transplanting,
the number of trees dying back from the cut ends and the extent of in-
vasion had increased in all lots and none of them appeared any better
than those of Lot 2.
After observing the behavior of these treatments and of non-treated
trees in commercial plantings, 10 trees each of Tahiti limes and Perrine
lemons were dipped in a wax emulsion containing 0.2 percent sodium
thiuram sulfate on May 1 at the nursery and brought to Gainesville and
set in an irrigated plot. After two months none of these trees or the
non-treated checks showed any signs of dying back at the cut ends. How-
ever, lime trees treated with shellac on the cut ends have shown more or
less injury. Perrine lemons have not shown any injury from this treat-
ment. None of the treatments retarded development of new growth.

A STUDY OF Sclerotium rolfsii Sacc. IN FLORIDA; ITS HOST
RELATIONS AND FACTORS INFLUENCING
ITS PATHOGENICITY
State Project 247 Erdman West
During the year eight of the original isolations of Sclerotium rolfsii
made from 43 sources died in culture. Two unreported hosts were found.
These were coffeeweed (Cassia Tora) and tung oil (Aleurites fordii). The
coffeeweed was attacked at the surface of the soil, which is the common
point of attack. Lesions on the tung oil were peculiarly limited to leaves
of the lower branches five to eight feet from the ground and showed no
connection with it. It has not yet been ascertained how they reached
this point.
Experiments during the past year have been concerned with a study
of the toxicity of various substances on the growth of the organism in
culture and in flats of soil. Materials tested included ammonium sulfate,
red copper oxide and aqueous merthiolate solution (sodium ethyl mercuri-
thiosalicylate). In the early experiments these were all made up in
1:1,000 strength in distilled water and a sufficient quantity of these stock
solutions was added to potato dextrose agar to give five dilutions ranging
between 1:3,800 and 1:15,000. At these concentrations ammonium sulfate
and red copper oxide showed no inhibiting effect on growth of the fungus,
while merthiolate inhibited all growth at all concentrations.






Annual Report, 1936


Further tests with merthiolate showed that a dilution of 1:150,000 also
inhibited all growth and killed the sclerotia, while dilutions of 1:500,000
and 1:15,000,000 permitted slight growth and a few sclerotia developed in
the latter concentration.
An experiment is in progress to determine the effect of merthiolate
solution on plants and S. rolfsii in the soil. So far it appears that dilutions
of 1:500,000 do not harm young annual larkspur plants, but the effect on
the fungus in the soil has not yet been ascertained.

A STUDY OF ROSE DISEASES IN FLORIDA AND THEIR CONTROL
State Project 253 W. B. Shippy, Leesburg
Foliage injury, jointly due to black spot and burning, was particularly
severe during 1935. Burning especially affected mature foliage, and was
not confined to rows treated with fungicides. Foliage damage due to these
causes first assumed importance in June and continued to be a severe drain
on the vitality of the plants until late autumn.
In the spray experiments the following fungicides were applied regu-
larly during the season at approximately weekly intervals over the period
May 7 to November 25, totalling 30 applications; ammoniacal copper car-
bonate, copper-lime dust, copper silicate spray, red copper oxide spray,
pine oil-copper resinate spray, basic copper sulfate spray and bordeaux
mixture 1-1-50. Based on records taken throughout the season on foliage
injury as well as amount of die-back, the treatments were rated in order
of their effectiveness as follows: (1) copper silicate, (2) basic copper
sulfate and bordeaux mixture 1-1-50, (3) red copper oxide, ammoniacal
copper carbonate, and copper-lime dust, (4) pine oil-copper resinate, and
untreated.
INVESTIGATIONS OF FRUIT ROTS OF GRAPES
State Project 254 K. W. Loucks, Leesburg
Further inoculation experiments with the black rot organism have shown
that infection of fruit develops only from inoculations made during the
blooming period and shortly after the fruit has set. The incubation period
for inoculations made last year varied from 25 to 37 days, indicating that
weather conditions influence it.
Inoculations made with the bitter rot organism produced infection when
made at any time after the fruits were three-fourths normal size. The
incubation period for the inoculations made last year varied from 40 to
56 days, depending upon the time that they were made in relation to age
of the fruit. On a basis of these findings spraying experiments were
initiated to find a more effective means of control of ripe and bitter rot.
Since bordeaux proved objectionable to use late in the season because
of the residue and copper acetate was not an effective substitute, several
stainless materials are being used to compare their effectiveness in pre-
venting ripe and bitter rots. Results of these tests will be obtained as
the crop is harvested.
A young planting has been started in which 23 varieties of grapes
are being propagated on eight varieties of rootstocks to determine the
comparative susceptibility of varieties on different rootstocks.
In another test for resistance, the wild species of grape, Vitis simpsonii,
has been crossed with three cultivated varieties. The first seedlings
are now two years old and part of them will be used next year to test
their adaptability as understocks.







Florida Agricultural Experiment Station


COLLECTION AND PRESERVATION OF SPECIMENS OF
FLORIDA PLANTS
State Project 259 Erdman West and Lillian Arnold'
Numerous additions of Florida plants were made to the herbarium
during the past year, collecting trips together with donations netting sev-
eral hundred specimens. Emphasis was laid on obtaining good specimens
of Florida trees.
Over 500 packets of Florida fungi were made up but none of these
has been incorporated in the herbarium as yet.
The collection of seeds begun this year now includes 285 species. These
seeds have been dried, stored in vials and will be used to supplement the
herbariumm material, as well as for reference in identifying seeds suspected
of poisoning livestock.
Through a cooperative arrangement with the New York State School
of Forestry, 75 specimens of American woods were received. These will
be supplemented with herbarium material from the same tree from which
the wood samples were obtained.
Considerable progress was made in mounting specimens collected in
past years. One student spent his entire available time in mounting and
labelling these specimens. About 4,000 specimens were mounted under this
arrangement, but much material remains unmounted and unavailable for
use. About 6,000 sheets of phanerogams, including nearly 4,000 of the
Cuthbert Collection, were made available for references. Nearly all of
the stored fungus collections were sorted and properly labelled, but they
have not been filed. A collection of 77 liverworts contributed by Mr. T. M.
Little has been mounted, labelled and placed in properly labelled genus
covers. The herbarium now contains about 33,600 specimens properly filed
with over 5,000 more undistributed, including fungi and higher plants.
The lettering of the genus covers with uniform type was finished this
year. A stamp of distinctive design was obtained which will identify
specimens from this herbarium wherever they may be exchanged. The
number of sheets so far numbered is 10,900, most of which have been
indexed on 4 x 6 cards.
Interesting and valuable information on methods of drying various
plant materials has been developed, especially the use of facial tissue on
certain delicate flowers. The use of highly absorbent blotters and artificial
heat at 150 F. have proved very effective under our humid conditions.
VIROUS DISEASES OF TOMATO AND PEPPER
State Project 264 A. N. Brooks, Plant City
Observations upon virous diseases of tomato and pepper were initiated
in October 1934. During the last three months of 1934 very little mosaic
was found on tomato and pepper growing in the West Coast area from
Bradenton to Fort Myers. However, on the following spring crop in
the same area much more mosaic was present, some fields showing 100
percent infection. A survey of the fields in the East Coast area during
the first week in April showed considerably less mosaic than was found on
the West Coast, but percentage of infection increased later in the season.
Mosaic also appeared later in the season in central Florida.
Very little mosaic appeared in any area during the 1935-36 season.
This probably was due to climatic conditions and their effect upon growth
of plants and upon development of insect vectors of virous diseases. Ex-
cessive rainfall in September ruined the seedbeds on both East and West
Coasts, resulting in a late and short crop of pepper and tomato. Continued:
I






Annual Report, 1936


*cold during the latter part of November and all of December prevented
maturing a crop.
During these two seasons an attempt has been made to determine the
viruses present in cultivated and wild plants and their relationships one
to another. This has been done mainly by inoculations into tomato and
pepper and by cross-inoculations into the various plants concerned, where
this was possible. The two methods of inoculation most commonly used
were by leaf rubbing and needleprick. By using these methods positive
results have been obtained with ordinary tomato mosaic virus, same as
Johnson's tobacco No. 1, on tomato (10 varieties tested), pepper (World
Beater, California Wonder, Florida Giant, Ruby King, Hungarian Yellow
Wax, Red Chili, Anaheim Chili, and Long Red Cayenne), Datura stramon-
ium, Turkish tobacco, and Nicotiana glutinosa. Negative results were
.obtained when this virus was inoculated into bean (Giant Stringless),
Bidens leucantha, Cassia Tora, Chenopodium album, C. ambrosioid-s, Com-
mclina sp., Crotalaria spectabilis, cucumber, potato (Red Bliss), sweet
potato, Phytolacca rigida, Solanum gracile, squash (Hubbard and small
,crook-neck) and tabasco pepper.
Positive results were obtained on tomato when healthy plants were
inoculated with extracts of mosaiced plants of Datura stramonium, pepper,
potato, tomato and Turkish tobacco. Negative results were obtained by
inoculating tomato plants with extracts of mosaiced plants of bean (Giant
Stringless), celery, Crotalaria spectabilis, cucumber, Datura metel, Cheno-
podium album, C. ambrosioides, Callicarpa americand, hybrid amaryllis,
lettuce (Big Boston), Phytolacca rigida, squash (Hubbard and small crook-
neck), sweet potato, Solanum gracile, Sida sp., and Bidens leucantha.
It was found that there probably are three viruses involved in pepper
mosaic, tobacco mosaic virus No. 1, celery or cucumber mosaic virus and
one not yet identified. However, these were not separated when most
of these inoculations were made and the results are grouped together in
this report. Positive results were obtained with these viruses on pepper
(same varieties as positive for tomato), tomato (10 varieties), Cassia Tora,
Commelina sp., Datura stramonium, Nicotiana glutinosa, Phyto'acca rigida
and Turkish tobacco. Negative results were obtained when these viruses
were inoculated into bean (Giant Stringless), B'dens leucantha, Cheno-
podium album, C. ambrosioides, Crotalaria spectabilis, cucumber, Solanum
gracile, squash (Hubbard and small crook-neck), sweet potato and tabasco
pepper.
Positive results were obtained by inoculating any of the bell peppers
with extracts from mosaiced plants of pepper, tomato, Cassia Tora, Com-
melina sp., Datura stramonium, Nicotiana glutinosa, Phytolacca rigida,
Turkish tobacco, and some labiate which was found in the Homestead area
in April 1935. Negative results were obtained under similar conditions
with extracts of mosaiced plants of bean (Giant Stringless), Bidens leu-
cantha, Chenopodium album, C. ambrosioides, Crotalaria spectabilis, cucum-
ber, Datura metel, Solanum gracile, squash (Hubbard and summer crook-
neck) and sweet potato.
Tomato mosaic virus was found to be active in vitro after 319 days
when stored in the refrigerator, after 54 days in vitro at room tempera-
ture, after 137 days in dried plant material at room temperature, after
70 days in plant material rotted to a slimy mass. All of these materials
are being retained to determine how much longer the virus will remain
active. Limit of longevity of the virus in plant refuse in field soil was
44-56 days during the winter months and 22-32 days during the spring
months; in steamed soil the corresponding times were 55-76 days and
:32-42 days.






Florida Agricultural Experiment Station


One of 50 tomato plants developed mosaic when the seed were planted
in steamed soil thoroughly moistened with extract of mosaiced tomato
plants and two of 50 plants developed mosaic when the seed were planted
in soil containing an abundance of mosaiced plant material. Every
precaution was taken to prevent chance infection and the seed were from
a lot that had never shown mosaic in any uninoculated plants.
Investigations on insect transmission of viruses has been greatly
hampered by the development of fungous diseases attacking the colonies
of aphids. However, Myzus persicae and Aphis gossypii have been found
to be vectors.
All commercial varieties of tomato tested have been found susceptible
to tomato mosaic. Of the pepper varieties tested only tabasco showed any
signs of resistance.
MISCELLANEOUS STUDIES
In addition to outlined projects, some work has been done on several
problems as opportunity permitted. During the last five years several
new materials have been introduced on the market for treating seeds
to control seed-borne diseases and to prevent damping-off of seedlings by
soil-borne organisms. At the request of growers tests have been conducted
with several of these materials to determine their comparative efficiency.
Two years ago it was observed that a recently introduced variety of
cantaloupe was generally resistant to downy mildew. The variety was
also variable for type and quality of fruit. Selections have been made
during the past two seasons at Bradenton and at Gainesville in an effort
to isolate a type that is uniform for resistance to downy mildew and qual-
ities of melon. Such a variety should also be valuable material for breed-
ing purposes.
Further studies have been made of the friendly scale fungi in an effort
to find a practical method for introducing them into citrus groves.
During the past two years gummosis of citrus apparently has been
increasing in importance. Studies made in the East Coast section have
shown that there is more than one form of gummosis, as determined by
the nature of the early stages. The two fungi, Diplodia natalensis and
Phomopsis citri, have been found particularly associated with the form
that originates in pruning wounds and other kinds of injuries. These
organisms invade large trunks and branches of trees and come to the
surface through the bark at considerable distances from the point of
infection.
Incidental to strawberry disease investigations, it was found through
four years' tests that plants obtained from Arkansas produced a higher
yield of marketable fruit than plants from Maryland. The plants ob-
tained from each source were multiplied under similar conditions in the
nursery and the progeny were then planted under similar conditions in
the field. The differences obtained were significant in every test.







Annual Report, 1936


SPECTROGRAPHIC LABORATORY
Work of the Spectrographic Laboratory consisted of three types: (1)
Spectrographic analysis of plant tissues, soils and other materials of
agricultural interest; (2) development and improvement of methods for
the quantitative determination of inorganic constituents; and (3) study
of organic constituents of plants.

A STUDY OF THE CHEMICAL COMPOSITION OF THE ASH OF
FLORIDA FRUITS AND VEGETABLES WITH REFERENCE
TO THE MORE UNUSUAL CONSTITUENTS
Purnell Project 201 L. W. Gaddum and L. H. Rogers
Spectrographic studies were made of the trace element content of
citrus fruit tissues, of corresponding cultivated soils, and of some typical
virgin soils in citrus areas. Considerable variation was found in the
trace element content of these materials. The data, however, are too
voluminous to present briefly and will be presented for publication at
some time in the early fall.
In cooperation with the State Chemist, spectrographic analyses were
made of the juices of certain varieties of citrus fruits. The results of
this work will be submitted soon for publication.
In cooperation with the Department of Animal Husbandry, spectro-
graphic analyses were made of certain mineral supplements used in cor-
recting deficiency diseases of livestock. Results of this work are reviewed
in the report of that Department.
In cooperation with the Department of Agronomy, spectrographic
analyses were made of centipede and other grasses. This was undertaken
in the endeavor to determine any significant differences in the trace element
content of grasses grown at Tifton, Georgia, and at Gainesville, Florida.
Results of this work are reported by the Agronomy Department.

A STUDY OF THE CHEMICAL PROPERTIES OF THE GLUCOSIDES
OF CITRUS FRUITS
Purnell Project 221 L. W. Gaddum
Work on this project was hampered considerably by lack of laboratory
facilities needed in the preparation of materials. In view of this difficulty,
work on this project was limited to the development of apparatus and
technique used in the study of spectra of organic compounds. In co-
operation with the Department of Physics, the tungsten under-water spark
gap and the hydrogen discharge tube were developed to a practical stage.
The equipment and operating technique were checked by reproducing ab-
sorption curves recorded in the literature, on anthracene, carotin and
other compounds.

THE DEVELOPMENT OF QUANTITATIVE SPECTROGRAPHIC
METHODS FOR AGRICULTURAL RESEARCH
Purnell Project 256 L. W. Gaddum, R. C. Williamson
and L. H. Rogers
Work was begun, in cooperation with the Department of Animal Hus-
bandry, on the development of a spectrographic method for the quanti-
tative determination of copper in animal tissues. Preliminary calibration
curves were made which indicate the proposed method to be satisfactory
for the determination of extremely small quantities of copper.








Florida Agricultural Experiment Station


In cooperation with the Department of Chemistry and Soils, a compari-
son was made of the chemical and spectrographic methods for the quanti-
tative determination of zinc. Approximately 40 samples of native grasses
and weeds from the Station farm have been analyzed by the two methods.
Duplicate analyses have been made on each sample, and in some cases as
many as 10 replicate determinations have been made. For about one-half
of the samples, the analyses by the two methods agree fairly well. In
other cases, where the analyses by the two methods did not agree, the
spectrographic determinations, in general, gave a larger value for the
zinc content than did the chemical determinations. Some of the residues
from the hydrochloric acid extraction (the first procedure in the chemical
method) were examined with the spectograph, and it was found, in some
cases, that as much as half the zinc present in the original sample was
retained in the residue, thus indicating that a modification of the extrac-
tion procedure is desirable.

SPECTROGRAPHIC STUDIES OF THE COMPOSITION OF TISSUES
AND CORRESPONDING SOILS OF NORMAL AND PHYSIO-
LOGICALLY DISEASED HORTICULTURAL CROPS
Purnell Project 266 L. W. Gaddum, A. F. Camp
and Walter Reuther

Cooperatively with the Department of Horticulture, spectrographic
determinations were made of the zinc content of leaves and petioles from
normal and bronzed tung trees and from normal, bronzed and frenched
citrus trees. The results of this work are reviewed in the report of the
Department of Horticulture.




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