Front Cover
 Table of Contents
 Letter of transmittal
 Board of control and station...

Group Title: Florida Agricultural Experiment station, report for the fiscal year ending June 30th.
Title: Report for the fiscal year ending June 30th
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00005173/00014
 Material Information
Title: Report for the fiscal year ending June 30th
Physical Description: 40 v. : ill. ; 23 cm.
Language: English
Creator: University of Florida -- Agricultural Experiment Station
Publisher: University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1915
Copyright Date: 1905
Frequency: annual
Subject: Agriculture -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
Statement of Responsibility: Florida Agricultural Experiment Station.
Dates or Sequential Designation: 1905-1930.
 Record Information
Bibliographic ID: UF00005173
Volume ID: VID00014
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 - AMF8112
oclc - 12029638
alephbibnum - 002452807
 Related Items
Preceded by: Report for financial year ending June 30th
Succeeded by: Annual report for the fiscal year ending June 30th ...

Table of Contents
    Front Cover
        Page 1
        Page 2
    Table of Contents
        Page 3
        Page 4
        Page 5
        Page 6
    Letter of transmittal
        Page 7
    Board of control and station staff
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
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        Page 15
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        Page 114
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        Page 118
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        Page 125
        Page 126
        Page 127
        Page 128
        Page 129
        Page 130
        Page 131
        Index 1
        Index 2
        Index 3
        Index 4
        Index 5
        Index 6
        Index 7
        Index 8
        Index 9
        Index 10
        Index 11
Full Text





ENDING JUNE 30th, 1915

v / '
--.' - '-'/

MAY, 1916

/ 006

jc r -


BOARD OF CONTROL ..------- -.....-------.--. _-- viii
EXPEIUMENT STATION STAFF ------------------------------- viii
Introduction ------------------------------------ -- xi
Lines of Work --...--------- ---------_-..---.--- _
Publications ------------------------------------------- xv
REPORT or ADrITOR ----------------------- ------- xvi
REPORT OF ANIMAL INDUTRIAL ------------------------------ xvii
Dairy Herd -------------------------------------------- xvii
Dairy Experiments --------------------------------- -- xviii
Hogs -------------------------------------------------- xxii
Pig-Feeding Experiments --------------------------------- xxii
Japanese Cane ------------------------------------- ---- xxi
Maiden Cane ------------------- ---------- xxxi
REPORT OF PLANT PHYSIOLOGIST ------------------------------- ii
Sand Cultures with Citrus Seedlings ------------------ xxiii
Pot Cultures with Citrus Seedlings -------------------- xlvi
REPORT OF ENTOMOLOGIST --------------.-------- ------.... xlix
The Velvet Bean Caterpillar --------------------.-- xlix
The Florida Flowc- Thrips ------------------------- lxiv
Camphor Thrips ------------------------ lx
Entomogenous Fungi ------------------------------------ lxxii
The Cottony Cushion Scale ------------------------------ xxiii
Miscellaneous Insects -------------------------------- lxv
REPORT OF PLANT PAHOLOGIST ------------------------------lxxvii
Gummosis ----------------------------------------I-- xxvii
Melanose ----------------------- -------------- --- hxxxn
Citrus Canker -------- --- - ------------ --- Ixxv
Pecan Diseases ----------------------------------
Miscellaneous Citrus Diseases .-- .- xciii
Celery and Tomato Seed-bed Diseases -i---v-- xdv
Prevailing Fungus Diseases of Vegetables --------xcvii
REPORT OF CHEMIST --- ---------- ---------------- xcix
Citrus Experimental Grove ---------------- ----------- xcx
Soil Tank Investigations ------------------------- ----- cii
Composition of Japanese Cane -------------------------- cv
REPORT OF ASSISTANT BOTANIST --------- ----------------- evii
Breeding work of the year ------------- ----------- cvii
Methods of Selection -------------------------- ----- eviii
Inheritance of Mottling of Seed Coat ---------- ------ exi
Inheritance of Length of Pod ------------ -------- exxvi
Corn Breeding -------------------- -- ------- --- cx


iv Contents

Introduction ------------------------------------------------- 8
Injuries caused by Whiteflies ----------------------------------
Life History of Whitefly -------------------------------------- 6
Natural Enemies of Whitefly -------------- ---------- 7
Control of Whitefly ----------------------------------------- 10
Food Plants of Whitefly .-------------------------------------- 18
Cloudy Winged Whitefly ------- --------------------- 20
Woolly Whitefly ------------------------------------------ 21

BULLEIN 124-Crraus CANKEm --I. PAGES 25-54.
History of Citrus Canker ----------------------------------- -27
Studies of Citrus Canker -----------------------------------. 31
Eradication of Citrus Canker---------------------------------- 44

PAGES 55-78
Boll-Worm, or Tomato Fruit Worm ----------------------------- 57
Root Knot ----------------------------------------------- 62
Thrips --------------- ----------------------------- 64
Cutworms --- ---------- _-- -------------- 66
Horn Worms ------------------- -------------- ---- 68
White Mold ---- --------- -------------------------------- 71
Aphis or Plant Louse ----------------------------------------72
Flea Beetles -------------------------------------------- 74
Miscellaneous Insects ----------------------- -- ----- 74

History and Bistribution ----------------------------------- 81
Appearance of Woolly Whitefly --------------------------------- 84
Control of Woolly Whitefly ---------- ---------- ---- 85
Severity of Infestation --------------------------------------86
Life History of Woolly Whitefly---------------------- ---------- 88
Damage Caused by Woolly Whitefly .--. --- --.-- ------- 92
Habits --------------------------------------- 94
Food Plants ---------- ---- ------------- -------- 94
Fungus Enemies ---------------- ------------------ ------- 95
Insect Enemies -- -- --97
Spread of Woolly Whitefly in Florida -------- 100

Introduction -----------------.--.------------- --------------. 105
Early Planting in Florida - ..--- ---- --- 106
Time of Ripening and Blooming -------------- --.---.--- 107
Propagation ---------------- ---------- -- 108
Culture -- -- 118
Fertilization ------- -------- -.-------- -----.-- 120


Marketing -------------------------------------------- 121
Mango Groups --------------------------------------------- 122
Culinary Recipes -------------------------------------------- 137
Literature -------------------- ------------------- 138


225.-Citrus Canker and Picking
226.-The Potash Shortage.
227.-Materials for Correcting Soil
228.-Using Ground Limestone.
229.-Controlling Cabbage Worms.
230.-Bulletins and Reports on
231.-Melon Worm and Pickle
232.-Silage Crops.
233.-The Melon Aphis.

234.-Yield of Japanese Cane with
Different Fertilizers.
235.-Fertilizer not Affecting Quality
of Cane Juice.
236.-Bulletins and Reports on Hand.
237.-Continuous Planting of Velvet
Preparation and Planting.
238.-Does Fertilizer Affect the Feed-
ing Value of Japanese Cane?


Hon. Park Trammell,
Governor of Florida,
Tallahassee, Fla.
SIR: I have the honor to transmit herewith the annual re-
port of the Director of the Florida Experiment Station, for the
fiscal year ending June 30, 1915.
Chairman of the Board of Control.

P. K. YONGE, Chairman, Pensacola, Fla.
T. B. KING, Arcadia, Fla.
E. L. WARTMANN, Citra, Fla.
W. D. FINLAYSON, Old Town, Fla.
F. E. JENNINGS, Jacksonville, Fla.

P. H. ROLFS, M.S., Director.
J. M. SCOTT, B.S., Animal Industrialist, and Assistant Director.
B. F. FLOYD, A.M., Plant Physiologist.
J. R. WATSON, A.M., Entomologist.
H. E. STEVENS, M.S., Plant Pathologist.
C. D. SHERBAKOFF, Ph.D., Assistant Plant Pathologist.
S. E. COLLISON, M.S., Chemist.
JOHN BELLING, B.Sc., Assistant Botanist, and Editor.
S. S. WALKER, M.S., Assistant Chemist.
JOHN SCHNABEL, Assistant Horticulturist.
A. C. MASON, B.S., Laboratory Assistant in Entomology.
JULIUS MATZ, B.S., Laboratory Assistant in Plant Pathology.
H. G. CLAYTON, B.S.A., Laboratory Assistant in Animal Industry.
C. D. McDOWALL, B.S.A., Laboratory Assistant in Plant Phy-
T. VAN HYNING, Librarian.
K. H. GRAHAM, Auditor and Bookkeeper.
E. G. SHAW, Secretary.
L. T. NIELAND, G.F., Farm Foreman.


Fig. I. Testing Varieties of Velvet Beans,




Fig. 2. Dairy Barn

t 4)'~

Report for Fiscal Year Ending

June 30, 1915

Hon. P. K. Yonge,
Chairman, Board of Control.
SIR: I have the honor to submit herewith my report on the
work and condition of the Agricultural Experiment Station for
the fiscal year ending June 30, 1915, and I respectfully request
that you transmit the same. in accordance with the law, to the
Governor of the State of Florida.

The work of the Experiment Station has been carried for-
ward during the year without interruption; the principal lines of
work that were inaugurated in previous years were continued.
The investigation of problems that have been under considera-
tion for a number of years are now beginning to give fruitful
results. The development of the State in material wealth and
the rapid development of the agricultural areas make insistent
and imperative demand upon the Experiment Station staff for
accurate data regarding the production of farm crops. The
rapid development of the extension work, due to the passage of
the Smith-Lever Bill, has given the Experiment Station men a
correspondingly greater freedom from interruption. The tech-
nical work of the Station has received more careful and more
continued attention than heretofore.

The lines of work heretofore laid down in the project plans
have been continued. Part of the projects have been considered
completed and publications issued on them. With this issuing of
the publications it is considered that the Experiment Station

Florida Agricultural Experiment Station

worker has completed his duties with reference to these par-
ticular problems. At times unusual and urgent demand is made
upon some of the technical workers, but such occasions are not of
frequent occurrence. Generally speaking the lines of work laid
down have been followed out carefully and consistently.
PLANT INTRODUCTION PROJECT. This work has been continued
during the year in cooperation with the Office of Seed and Plant
Introduction in the Bureau of Plant Industry. The seeds and
plants furnished us by the Bureau have all been tested in the
field. Some have proved to be quite worthless; others have
shown weakness in one or another direction; a few have suc-
ceeded. This condition was to be expected in beginning the
The re-planting of various numbers of velvet beans has been
continued. The notes on these plantings show no reason for us
to change our mind as to the importance and value of the varie-
ties tested. Among the novelties in the velvet beans is a segre-
gate from the Florida speckled bean (Stizolobium deeringia-
num) which has occurred in Georgia. This segregate has the
quality of ripening much earlier than the Florida velvet bean.
In appearance of the plant and appearance of the pod as well as
the seed, it cannot be distinguished from the Florida velvet.
The only marked difference is its earliness in ripening. Coinci-
dent with the earliness in ripening is also a decrease in the
amount of foliage and vine produced. (Fig. I.)
DAIRYING PROJECT. The principal work done in the Animal
Husbandry Department has been confined to the testing of the
dairy herd and a determination of the feed cost of milk pro-
Data have been kept as to the effect on milk flow produced
by dipping the animals for tick eradication. The results of
this work seem to indicate that for five days following the dip-
ping the milk flow of the herd thus treated was decreased
8.68 per cent.
NEW BUILDINGS. During the year a new dairy barn has
been built from an appropriation by the Legislature. This barn
will be used in dairying experiments. A portion of the barn
will be used exclusively by the Experiment Station; another
portion by the Department of Animal Husbandry of the College
of Agriculture. The total cost was approximately $10,000. The
central portion of the barn contains a large pavilion where cat-
tle judging may be done. Three concrete silos have been con-

Annual Report, 1915

structed. Two are for the preservation of the ordinary forms of
silage, such as corn, sorghum and Japanese cane, while the third
and smallest (capacity about 25 tons) is for conducting experi-
ments in making sweet potato silage, and also for experiment-
ing with sweet potato silage in milk production. (Fig. 2.)
HOG FEEDING PROJECT. The work of testing different Flor-
ida grown feeds for pork production has been continued. The
dasheen was one of the crops tested in this way. Raw dasheens
were fed in various proportions with shelled corn and velvet bean
meal. The results of the work up to the present have not been
favorable to the use of dasheens as a pork producing food.
PLANT PHYSIOLOGY PROJECT. The principal work conducted in
Plant Physiology this year has been that of testing different
elements or chemicals used as fertilizers in citrus groves and
also the testing of other elements not directly employed in such
manner. The definite object in the work was to ascertain the
effects of these different materials upon the citrus tree. The
technical work in these experiments was conducted in the green-
house where moisture conditions were under perfect control. In
the field weather conditions are changeable and for that reason
do not give reliable and consistent results.
ENTOMOLOGY PROJECT. The principal work carried on by
the entomology department has been the study of the velvet
bean caterpillar and the study of thrips affecting the bloom of
various economic plants. The material in connection with the
velvet bean caterpillar will be ready for distribution during
the next fiscal year. A considerable number of experiments
have been made to determine the usefulness of certain insecti-
cides in controlling or preventing the ravages by thrips on
various crops such as tomatoes, citrus, and others.
PLANT PATHOLOGY PROJECT. During the year a considerable
amount of time has been given to the technical study of citrus
canker. This bacterial disease has been but recently discovered
in the State. The virulence of the bacterium and the serious
results following its attack have made it imperative to secure as
large a fund of technical information as could be obtained in
the least possible time. Fortunately the whole question of cit-
rus canker eradication was taken over by the State Plant Board,
thus relieving the Experiment Station of serious consideration
Sof this matter.
PECAN DISEASES. A considerable amount of time has been
Devoted to the study of a pecan disease, with the desire to find

Florida Agricultural Experiment Station

a remedy for it. Some progress has been made in the direction
of securing a suitable remedy for the disease.
TRUCK CROP DISEASES. A considerable amount of attention
has been given to the diseases affecting certain truck crops,
especially those diseases which are likely to be distributed from
the seedbeds to the fields. The work was somewhat interrupted
by the injection of the citrus canker consideration, but con-
siderable progress has been made in the direction of understand-
ing somewhat clearly the different causes underlying truck crop
diseases, especially where the agents are transferred from the
seedbed to the field.
continued exactly in the lines laid down some years ago. The
work of fertilizing the citrus grove near Tavares has been con-
tinued. Notes have been taken on the different trees, and con-
ditions of the soil noted.
The investigations of the drainage water caught from the
soil tanks on the Experiment Station grounds have given in-
teresting and important results.
PLANT BREEDING PROJECT. The work of this project during
the year has been confined to the breeding of velvet beans and
the breeding of a few lines of corn. The velvet beans have been
bred primarily for establishing different races from the hybrids
made several years ago. Further crosses have been made and
these crosses have thrown much light on the various hybrids
of the velvet bean family. Three valuable varieties, Wakulla,
Osceola and Alachua, have been grown in considerable quantity
and the seed distributed to various farmers in the State. (Fig 1.)
CHANGES IN STATION STAFF. From July 1, 1914, to July 1,
1915, the following changes took place:
On July 1, 1914, H. G. Clayton, B.S.A. (Fla. Agric. Col.),
began work as Laboratory Assistant in Dairying. On August
1, 1914, C. D. Sherbakoff, Ph.D. (Cornell University), accepted
the position of Assistant Plant Pathologist. On August 1, 1914,
L. T. Nieland was appointed Farm Foreman. In October, 1914,
Edgar Nelson resigned the position of Assistant to the Plant
Physiologist. On June 1, 1915, C. D. McDowall, B. S. A. (Fla.
Agric. Col.), took up the duties of Laboratory Assistant in Plant

Annual Report, 1915

No. Title Date and Author
225 Citrus Canker and Picking Implements- Oct. 14, 1914-H. E. Stevens
226 The Potash Shortage .------------- Oct. 31, 1914-S. E. Collison
227 Materials for Correcting Soil Acidity-..- Nov. 14, 1914-P. H. Rolfs
228 Using Ground Limestone---------------Nov. 21, 1914-P. H. Rolfs
229 Controlling Cabbage Worms-.....- ----Dec. 19, 1914-J. R. Watson
230 Bulletins and Reports on Hand---- ---------- Jan. 16, 1915
231 Melon-Worm and Pickle-Worm--------- Feb. 18, 1915-J. R. Watson
232 Silage Crops-- ----.-----.March 6, 1915-J. M. Scott
233 The Melon Aphis--------------.-----. April 3, 1915-J. R. Watson
234 Yield of Japanese Cane with Different Fertilizers-.
----------------- ---... -----...April 10, 1915-J. M. Scott
235 Fertilizer Not Affecting Quality of Cane
Juice ----------------------- April 24, 1915-3. M. Scott
236 Bulletins and Reports on Hand-----------------_. May 1, 1915
237 Continuous Planting of Velvet Beans--. May 15, 1915-J. M. Scott
238 Does Fertilizer Affect the Feeding Value of
Japanese Cane?--------------------June 5, 1915-J. M. Scott

123 Whitefly Control, 1914, 24 pages---------.Sept. 1914-J. R. Watson
124 Citrus Canker, I, 30 pages------- Oct. 1914-E. W. Berger, H. E.
Stevens, Frank Stirling
125 Tomato Insects, Root-Knot and "White Mold,"
24 pages--- -----------------Dec. 1914-J. R. Watson
126 The Woolly Whitefly, 24 pages ...------ March 1915-J. R. Watson
127 Mangoes in Florida, 36 pages-...-----....June 1915-P. H. Rolft
ANNUAL REPORT for 1914; 106 pages, with index
to all publications of the year.

Florida Agricultural Experiment Station


P. H. Rolfs, Director, Florida Experiment Station.
SIR: I respectfully submit the following report of the credits
received and expenditures vouchered out of funds as specified:

Sales and appro-
Hatch Adams Donations priation
By balance on hand, July 1, 1914 ------------------ 694.48 ---....
By Appropriation from U. S.
Treasury ---------------- $15,000.00 $15,000.00 ------- -----
By appropriation from State
Treasury ------------------------------ --------- $3,000.00
By receipts, Sales Fund and do-
nations ----------------------- --- ----- $ 1,301.92 ----...
Total --------------------$15,000.00 $15,000.00 $ 1,996.40 $3,000.00


To salaries ------------------- $ 5,687.66
Labor ------------------------ 3,668.36
Publications ----------------- 1,290.37
Postage and stationery-------- 652.44
Freight and express-----------. 254.84
Heat, light, water, power------- 143.05
Chemicals and lab. supplies--- 46.00
Seeds, plants and sundry supplies 196.49
Fertilizers ------------ ------ 228.78
Feeding stuffs --------------- 1,709.34
Library --------------------- 482.82
Tools, mach. and appliances--.. 240.44
Furniture and fixtures--------- 34.67
Scientific apparatus and speci-
mens ------------------ -- 18.37
Live Stock ------------------ 7.00
*Traveling expenses ------------ 105.32
Contingent expenses -------- 20.20
Buildings and land ------ 213.85
Repairs, farm drainage ......-------
Repairs, fence, incl. posts, etc.- ------
-Repairs, painting farm buildings,
gardener's cottage, etc. .--. -------.
Making road and fill-in to farm----------
Equipment, buildings -- --- ---------
Balance ----.. -----....- ---------
Total ---------------$15,000.00




$ 326.25



147.62 ------ ------
--------- --------- --------
491.22 88.27 .......-
------ 7.20 ----...
243.38 300.80 -------
----- -- 244.41
------- ---- 578.44

-------.. ---------
- 807.46
$15,000.00 $ 1,996.40


Respectfully submitted,

Annual Report, 1915 .

P. H. Rolfs, Director.
SIR: I submit the following report of the Department of Ani-
mal Industry for the year ending June 30, 1915.

During the year three Jersey bulls were donated:
Magnolia's Noble Pogis No. 131234 by the Owl's Noble Duke
No. 104321 out of Figgis of Florida No. 285501. This is a well
bred young bull. On his sire's side he is a grandson of Noble
of Oakland No. 95700. On his dam's side he is a great-grandson
of Sophia 19th of Hood Farm No. 189748. This young bull was
donated by Mr. P. K. Yonge, Pensacola, Florida.
Prince Landseer Tormentor No. 130913 byBisson'sFancyPrince
No. 93103, he by Bisson's Landseer's King No. 57793, and out
of Landseer's King's Torment No. 246134 out of Marigold's Tor-
ment No. 204057. This young bull was donated by the Ewell
Farm, Spring Hill, Tennessee.
Elberta's Eminent Fox No. 135708 by Elberta's Eminent No.
93871 by Oxford Fern Jap No. 80616, he by The Jap P No. 3713
out of Fox's Romping Lass No. 242809. This animal was donated
by Miss M. 0. Chase of Valrico, Florida.
The old herd bull, Royal's Golden No. 84018, was used at the
head of the Experiment Station herd as long as it was advisable
to use him. He was therefore exchanged for Agatha's Gipsy
Prince of K. V. F. No. 87041 by Agatha's Gray Prince No. 67824
by Agatha's Flying Fox No. 3256 out of Gipsy Girl of Belmont
No. 203237.
No other additions have been made to the herd except the
increase which has been as follows: fourteen calves of which
six were purebred Jersey, four heifers and two bulls. One
Jersey bull was sold to Mr. S. M. Wagner of Inverness, Florida,
and the other is still in the herd. All of the heifer calves will
be retained in the herd to replace the older and unprofitable cows.




Florida Agricultural Eperiment Station

RECORD JULY 1, 1914, TO JUNu 80, 1915
Table showing cow numbers, age, breed, number of days in milk, pounds of
milk and percentage of butter fat.

z I .d .
S a- aI

1 7 Grade Jersey 848 5173.5 6.1
4 7 Grade Jersey 213 1695.3 4.7
5 15 Grade Jersey 198 1958.4 4.4
6 14 Grade Jersey 343 2821.4 4.2
7 7 Grade Jersey 211 2508.1 5.1
9 7 Grade Jersey 272 4400.7 5.3
10 14 Grade Jersey 277 3725.1 5.3
14 7 Half Shorthorn 225 2226.1 5.4
and Native
15 6 Grade Jersey 149 1164.2 5.2
17 4 Jersey 210 1661.9 5.5
18 4 Jersey 303 3479.7 5.0
20 4 Jersey 305 2955.4 4.9
21 3 Grade Jersey 264 2995.3 i 5.2
22 3 Grade Jersey 132 872.4 5.9
23 3 Grade Jersey 60 206 3.0
24 3- Grade Jersey 160 1119.4 4.9
25 3 Grade Jersey 221 1922.7 5.1
26 3 Grade Jersey 243 2051.6 5.8
27 3 Grade Jersey 203 1631.0 4.7
37 I 3 Jersey I 306 1917.3 5.7
38 3 Jersey 87 504.8 5.2
40 3 Grade Jersey 121 498.1 4.6
41 3 Grade Jersey 365 2958.2 5.1
42 7 Grade Jersey 328 2994.4 4.3

Annual Report, 1915

RfoMRD JULY 1, 1914, TO Juil 80, 1915.
Table showing cow numbers, pounds of butter, value of butter, gallons of
milk, value of milk, cost of feed, feed cost of milk per gallon, profit on milk
over cost of feed, profit on butter over cost of feed.

d 03

04 I 1 IId ___> v __4 A_ I___
1 368.18 147.27 601.5 192.50 I 59.84 .099 132.66 87.48
4 92.95 37.18 197.12 63.08 25.27 .128 87.81 11.91
5 100.52 40.21 227.7 72.87 27.59 .121 45.28 12.62
6 138.25 55.30 328.0 104.98 43.99 .134 60.99 11.31
7 149.23 59.69 291.63 93.32 31.92 .106 61.40 27.77
9 272.11 108.84 511.70 163.74 38.30 .074 125.44 70.54
10 230.34 92.14 433.15 138.61 49.54 .114 89.07 42.59
14 140.24 56.10 258.84 82.83 42.16 .162 40.67 13.94
15 70.63 28.25 135.37 43.32 16.39 .121 26.93 11.86
17 106.64 42.66 193.24 61.84 32.22 .166 29.62 10.43
18 202.98 81.19 404.61 129.47 50.56 .124 7891 30.63
20 168.94 67.58 343.64 109.96 43.81 .127 66.15 23.76
21 181.71 72.68 348.29 111.45 44.32 .127 67.13 28.36
22 60.05 24.02 101.44 32.46 19.60 .192 12.86 4.42
23 7.21 2.88 23.95 7.66 3.72 .155 3.94 -.84
24 63.99 25.60 130.16 41.65 21.84 .167 19.81 3.76
25 114.40 45.76 223.56 71.54 25.49 .114 46.05 20.27
26 138.82 55.53 239.72 76.71 30.77 .120 45.94 24.76
27 89.44 35.77 189.65 60.69 34.18 .180 26.51 1.59
37 127.49 51.00 222.94 71.34 40.18 .189 31.16 10.82
38 30.63 12.25 58.69 18.78 11.86 .202 6.92 .39
40 26.76 10.70 58.00 18.56 6.70 .115 11.86 4.00
41 176.02 70.41 343.97 110.07 41.55 .127 68.52 28.85
42 200.38 80.15 464.46 148.63 52.44 1 .112 96.19 27.71

Table 2 gives some interesting figures on the rettn., f om
the individual cows in the dairy herd. It shows theimposttnec\
of keeping a daily record of the performance of' each cow in the'/
herd. With the information that can be obtained from the daily.,
milk and feed record it is easy to determine the cost pf produc-
ing a gallon of milk from each cow in the herd. Tle ue~s oh
of whether dairying is profitable or not is easily settled. Or, in.'
other words, the profitable dairy cows can be selected and the
unprofitable ones discarded. This table shows 6thW there is~~ '
great variation in the feed cost of milk per gallon. A tV (Uttance,
cow No. 9 produced milk at a cost of 7.4 cents per gallon for
feed, while with cow No. 38 the feed cost per gallon of milk was

Florida Agrioultural Experiment Station

20.2 cents, an advance in cost of production of 275 per cent. The
reader can decide which of the two cows would be the most
profitable dairy animal.
The average feed cost per gallon of inilk for the entire herd
of twenty-four cows was 13.6 cents. If we select the ten best
cows in the herd, the average feed cost per gallon of milk is 11
Scents. The table also shows the value of the milk when sold at
32 cents per gallon, and when converted into butter and sold at
40 cents per pound. This shows that a much larger profit is
obtained from selling milk than from converting it into butter.

To determine the effect that dipping has on the milk flow,
complete records were kept on nine cows in the dairy herd.
A record of the milk produced was made during five days
preceding the date of each dipping, and a similar record was
kept of the milk produced for five days after each dipping. These
records were kept from June 1 to August 23, 1914, a period of
84 days, during which the cows were dipped six times. The
cows were dipped every two weeks.
The cows were driven half a mile to and from the dipping vat
each time they were dipped. In addition to the drive from the
barn to the dipping vat, the cows were from an hour to an hour
and a half late in getting to pasture each morning when they
were dipped. These two-circumstances would have a tendency
to reduce the milk flow, as well as the dipping.
In the five days before the first dipping the nine cows pro-
duced 376.9 pounds of milk. The same cows in the five days
after the dipping produced 341.1 pounds of milk, or a decrease
of 5.;8 founds.
..In the five days before the second dipping the nine cows pro-
/ .duced 281.5 pounds of milk, and in the five days afterward they
'gave 251.2 pounds, .a decrease in the flow of 30.3 pounds of milk.
n the Ave days before the third dipping, the nine cows pro-
duced 296 pounds of milk, and in the five days afterward they
gave 264 poundsi.a decrease of 32 pounds.
SIn .the fime'aqs before the fourth dipping, the cows gave 248.5
pounds, f Milk, and in the five days afterward they produced
211.9 pounds, a decrease of 36.6 pounds.
In the five days before the fifth dipping they produced 187.7

Annual Report, 1915

pounds of milk, and in the five days after they gave 204.3 pounds,
an increase of. 16.6 pounds.
In the five days before the sixth dipping the cows produced
187.1 pounds of milk, and in the five days thereafter they gave
168.1 pounds, a decrease of 19 pounds.
In the six five-day periods before dipping the nine cows gave
1577.7 pounds of milk. In the six five-day periods after dipping
the same cows produced 1440.6 pounds of milk, or a total de-
crease in flow of milk of 137.1 pounds, or a loss of 8.68 per cent
in six dippings.

Milk produced five days before Milk produced five days after
dipping. dipping.
Cows No. 1-2-7-9-11-15-37-40 and 41 Cows No. 1-2-7-9-11-15-37-40 and 41
Date Pounds Date Pounds
June 1 to 6-----------------...376.9 June 7 to 12..-----.. ------.341.1
June 15 to 20---..----.-----281.5 June 21 to 26--------------- 251.1
July 1 to 6 ---------------_.296.0 July 7 to 12----------------..264.0
July 15 to 20--------------- 248.5 July 21 to 26--------------- 211.9
July 29 to August 3---------. 187.7 August 4 to 9-- ....---------204.8
August 12 to 17------------_187.1 August 18 to 23--------------168.1
Total --------------------1577.7 Total -------------------- 1440.6
Decrease due to dipping 187.1
pounds or 8.68 per cent.

During the year an experiment in feeding calves was con-
ducted. Twelve grade Jersey heifer calves were selected and
divided into three lots of four calves each. In making up the
different lots of calves, age and size were considered so that the
calves in the various lots were as uniform in this respect as it
was possible to get them.
Lot I was fed 4 quarts of whole milk per calf per day.
Lot II was fed 4 quarts whole milk and 12 ounces of oat meal per calf
per day.
Lot III was fed 8 quarts of whole milk per calf per day.
Each lot of calves had one-tenth acre of Dwarf Essex rape pasture.
The experiment continued for 35 days. During the 35 days
the calves in lot I gained 64 pounds. The calves in lot II in the
same time gained 146 pounds, and the calves in lot II gained
231 pounds.

Florida Agricultura Ezperiment Station

This shows a difference in favor of whole milk over either of
the other rations.
The calves in lot I did not get a sufficient amount of milk to
make satisfactory gains. For that reason the calves in lot I
made a poor showing in the gain produced.
The following tables show the result in detail:


Four calves in each lot Lot I Lot II Lot III
Pounds Pounds Pounds
Weight at beginning ------------------------ 399 401 396
Weight at close of experiment-----.------- 463 547 627
Total gain per lot--------------------------- 64 146 281
Average daily gain per head ----------- .457 1.04 1.65
Average gain per day per 1000 Ibs. live weight-. 4.5 10.3 16.60

Lot I Lot II Lot II
Whole milk ------------------------------4 qts. 4qts. 8qts.
Oat meal ---------------------------------- 12 oz

All calves had Dwarf Essex rape pasture..
Boiling water was poured over the oat meal before it was fed.

There have been no additions to the breeding herd since the
last report other than the increase.

One pig feeding experiment was conducted during the year
in which nineteen pigs were used. These nineteen pigs were
divided into four lots of five pigs each except lot HI which con-
tained four. The pigs in each lot were as nearly equal in size
and quality as it was possible to divide them.
Lot I was fed shelled corn only.
Lot II was fed shelled corn one part and raw dasheens four
parts by weight.
Lot III was fed shelled corn and raw dasheens equal parts by
Lot IV was fed shelled corn one part, raw dasheens four parts
by weight and a small amount of velvet bean meal was added.


Annual Report, 1915

The feed in this experiment was figured at the following
prices: corn $1.85 per hundred; dasheens at $0.667 per hun-
dred, and velvet bean meal at $.40 per hundred.
This experiment began March 4 and continued for fifty-nine
days. The following tables give in detail the results of this test.
It will be seen by looking at the table of weights and gains
that lot I fed on shelled corn only, made the best daily gain. Lot
III fed corn and dasheens equal parts by weight comes next in
order of daily gain produced. Lot II fed corn one part and
dasheens four parts by weight made the least average daily
gain. The dasheens used were the variety Trinidad. In order
of cost per pound of gain they ranked, lot III, lot I, lot IV, and
last lot II. None of these results is satisfactory in daily gain or
cost per pound of gain.
From the results of this test one is inclined to believe that
dasheens are not of much value as a hog feed.
Tables numbered 6, 7 and 8 give the results of the test in
Lot Lot Lot Lot
I n m iv
lbs. lbs. lbs. lbs.
Weight at beginning of experiment, Mar. 4,
1915 -------------- --------- 344 338.4 268 340.8
Weight at end of 59 days-...-------------- 478.6 370 359 395.6
Total gain for 59 days----- 134.6 31.6 91 55.8
Average daily gain per head --------------- .456 .1074 .3854 .1874
Average daily gain per 1000 lbs. live weight- 6.628 1.587 5.753 2.758
Feed to make 100 pounds gain-------------- 635.2 3263.9 820.4 2004.8
Cost per pound of gain--------------- --$.1175 $.2955 $.1033 $.1746
Cost per 100 lbs. of gain------------------ $11.75 $29.55 $10.33 $17.45


Florida Agricultural Experiment Station

Lot I 856 pounds corn at $1.85 a hundred------------------$1.82
Total --------------------- $15.82
Lot 11 207.4 pounds corn at $1.85 per hundred-------------- 3.84
824 dasheens at $.667 per hundred-------- 5.50
Total ---- ----- ---- $ 9.34
Lot III 873.3 pounds corn at $1.85 per hundred-- ------------- 6.91
373.8 dasheens at $.667 per hundred ----- 2.49
Total ---------------... 9.40
Lot IV 207.4 pounds corn at $1.85 per hundred------------------ 3.84
824 dasheens at $.667 per hundred--------- 5.50
77 velvet bean meal at $.40 per hundred------ .31
Total ---------------$ 9.65

Corn Dasheens bean meal
Pounds Pounds Pounds
Lot I ---------------------- 2.8 -
Lot II ----------------------- .7 2.8 --
Lot I ----------- ---------- 1.4 1.4 ---
Lot IV -------------------.7 2.8 .5

The fertilizer experiment with Japanese cane was begun in
the spring of 1909 and continued until the crop of 1914 was
harvested. Hence we have the results of six crops. The annual
reports for 1910-11-12-13 and 1914 give the results obtained
from year to year.
The following tables give the results obtained.



1 2 3 4 5 6 7 8

Dried Blood --------------- 112 112 112 112 112
Sulphate of ammonia---------- --- -- --_ 72 -- 72 ..- --
Muriate of potash ----------- 84 84 -_ 84 84 -. --- ----
Sulphate of potash ----------- --- --- --- --- -- 84 84 84
Acid phosphate ----------- --- 224 224 224 224 224 224 224
Ground limestone ------- ___------ ...- . -_ 2000
Total ----------------- 196 308 336 880 420 880 420 420
Ground limestone was applied in 1909, 1911, 1913.


Annual Report, 1915


for six
Plot -------- 1909 1910 1911 1912 1913 1914 years
1 -------- 24.20 14.60 7.08 6.38 8.16 5.31 10.95
2 --------- 17.70 12.40 9.00 6.84 6.93 5.05 9.65
3 --------- 16.10 10.00 9.63 3.68 8.83 2.07 7.55
4 ------ 19.10 14.40 14.36 7.92 8.51 6.87 11.87
5 --------- 19.54 11.80 13.56 7.26 8.09 5.25 10.91
6 ----- 18.90 16.70 15.48 9.62 7.86 6.73 12.54
7 -------- 16.60 14.10 14.02 10.68 9.33 7.26 11.99
8 --------- 27.03 16.00 14.10 10.28 8.92 5.89 13.70

Percentage of Sucrose Plot Plot Plot Plot Plot Plot Plot Plot
1909 ----------- 11.85 13.50 13.75 13.65 13.60 13.50. 13.58 13.75
1910 ---------- 11.00 10.85 10.50 11.00 11.20 11.10 10.95 10.90
1911 ----------- 9.301 9.24 6.12 9.00 7.92 6.90 8.12 9.18
1912 ----------- 11.25 11.12 11.17 12.14 11.48 11.65 11.37 11.87
1913 ---------- 11.00 10.10 9.80 10.72 10.87 11.08 10.61 11.06
1914 ----------- 8.97 8.89 7.63 8.93 9.97 9.13 9.23 8.57
Average for six years--- 10.56 10.61 9.83 10.91 10.84 10.56 10.64 10.89

Density of juice (Brix)
1909 --------- 16.70 17.20 17.70 17.40 17.40 17.50 17.60 17.80
1910 ---------- 15.35 15.40 15.30 15.40 15.60 15.60 15.50 15.50
1911 ----------- 14.00 13.90 13.60 13.50 14.00 14.20 14.80 14.20
1912 ---------- 15.40 15.48 16.05 16.28 15.63 15.70 15.60 16.00
1913 --------- 15.27 14.82 14.47 15.22 15.18 15.25 15.00 15.16
1914 ----------- 15.43 15.90 16.33 16.00 16.68 17.28 17.58 11.28
Average for six years-. 15.36 15.45 15.58 15.63 15.75. 15.92 15.98 15.98
1909 --------- 11.85 13.50 13.75 13.65 13.60 13.50 18.58 18.75

Plot i1 2 3 4 15 6 1 7 8

Moisture --- 5.06 2.70 4.21
ProteinNx6.25 1.70 2.42 2.44
Ether Extract 1.80 1.57 1.74
Crude fibre -- 34.52 33.48 33.27
free extract 54.62 56.04 55.54
Ash -------- 4.31 3.78 3.24
Nitrogen -.- .2716 .388 .386
Phosphoricacid .319 .385 .362
Potash ---- .891 .733 .791
Lime ------ .504 .543 .529
Magnesia --- .231 .249 .288
Determinations on air-dry samples.










xxvi Florida Agricultural Experiment Station

Plot Plot Plot Plot Plot Plot Plot Plot Aver-
1 2 3 4 5 6 7 8 age
1909 -------------- 122 89 81 96 98 95 83 136 100
1910 ------------- 106 90 73 105 86 121 108 116 100
1911 -------------- 8 74 79 117 112 127 115 116 100
1912 ------------- 81 87 47 101 93 123 136 131 100
1913 -------------- 106 90 50 111 105 102 121 116 100
1914 - ----- 96 91 37 124 95 121 131 106 100
Six-year average 95 87 61 109 98 115 115 120 100

The table showing the yield of green material produced each
year shows that there was a gradual decrease in yield of each plot
after the first year. This annual decrease may be due, perhaps,
to an insufficient amount of fertilizer to maintain the yield, or
it may be that the rattoon cane does not produce as heavy a yield
as canes.
We have kept records of yields from other plots of Japanese
cane here on the farm, and find that there is a decrease in yield
after the first year.
We find on comparing plots I and I that plot I, which was
fertilized with dried blood and muriate of potash, gave an aver-
age yield during six years of 10.95 tons of green material per
acre. Plot III, which received dried blood and acid phosphate,
produced an average yield during six years of only 7.55 tons
green material per acre, or 8.4 tons per acre of green material
less than dried blood and muriate of potash.
When we compare the yields obtained fr6m plots I, I and III,
we see that plot II, fertilized with. muriate of potash and acid
phosphate, produced a better average yield per acre during six
years than did dried blood and acid phosphate; but plot I, which
received dried blood and muriate of potash, produced a little
better yield per acre than did plot II, which was fertilized with
muriate of potash and acid phosphate.
The results obtained from these three plots by using an incom-
plete fertilizer would indicate that the best results from an in-
complete fertilizer might perhaps be obtained from dried blood
and muriate of potash. The results on these three plots show
one very important fact, and that is, that Japanese cane to pro-
duce the best yield requires potash. Plot I produced 30 per cent
larger yield than did plot III, and plot II produced 25 per cent
larger yield than did plot III.

Annual Report, 1915

To get the effect of dried blood we should compare plots 1
and V. These two plots were fertilized alike except that plot II
received no dried blood. Taking an average of six years plot
V produced 1.26 tons more green material per acre than did
plot II.
Comparison of the yields obtained from plots II and IV will
give us the effect of sulphate of ammonia. The average yield
per acre of green material from plot II, fertilized with muriate
of potash and acid phosphate, was 9.65 tons green material, and
from plot IV, fertilized with sulphate of ammonia, muriate of
potash and acid phosphate, was 11.87 tons green material, or
a difference of 2.22 tons in favor of the use of sulphate of
By comparing the yields from plots IV and VI we get the
effect of the different sources of potash. Plot VI, which received
sulphate of potash, produced a slightly better average yield dur-
ing six years than did plot IV, which received muriate of potash.
The difference, however, was only 0.67 of a ton green material
in favor of sulphate of potash.
A comparison of the yields from plots IV and V and also
from plots VI and VII will give the results of dried blood com-
pared with sulphate of ammonia. It is evident that the two plots
which received sulphate of ammonia produced slightly better
yields than the two plots that reAiv&edied blood.
The yields obtained from plots VII and VIII show the effect
of the use of ground limestone. The average for six years shows
a difference in yield of 1.7 tons green material in favor of ground
limestone. There is one important point to be noted. Altho
ground limestone was applied in 1909, 1911 and 1913, it did not
increase the yield except in 1909. In fact, the yield from plot
VIII, which received ground limestone, was just a little lower
in 1912 and in 1913 than from plot VII, which received no ground
limestone. In 1914 the yield from plot VIII was considerably
lower than from plot VII.
Each year a sample of twenty stalks was cut from each plot.
These twenty stalks were selected from various portions of the
plots so as to obtain a sample as nearly uniform as. possible.


xxviii Florida Agricultural Experiment Station

These twenty stalks were stripped, then weighed. They were
then run through a small hand power mill and the juice collected
and weighed from each sample. Each sample of juice was then
tested for the percentage of sucrose. The juice was also tested
for density. Table 11 gives the results of these tests. The per-
centage of sucrose in the juice varies somewhat from year to
When the results for six years are compared, there is but
little difference found in the percentage of sucrose from the vari-
ous plots. The percentage of sucrose in the juice from plot III
is just a little lower than that from any other plot. This might
indicate that potash was necessary in the fertilizer for cane.
However, the difference is only about one per cent for the aver-
age of six years between plot III, the lowest, and plot VIII, the
highest. This indicates strongly that fertilizer does not change
the percentage of sucrose in the juice.

Table 12 shows the analysis made from the crop grown on
plots fertilized as shown in Table No. 9 for five years. Any
effect that previous fertilizing might have had would be almost
Plot I, which had received no ammonia for five years, pro-
duced a crop with almost the maximum percentage of protein.
If the fertilizer had any effect on the composition of the crop,
the effect would have clearly shown in this case by the produc-
tion of a crop with a low percentage of protein.
There is not enough difference in the composition of the Jap-
anese cane from the different plots to indicate that the fertilizer
has any influence on the composition of the crop.

1. On the soil on which the cane was grown potash is the
most beneficial.
2. Nitrogen seems to be the next in importance to potash as
a fertilizer on the soil on which this experiment was conducted.
3. Phosphate seems to be not so important as nitrogen and
4. Ground limestone acted as a temporary stimulant. No

Annual Report, 1915

beneficial results were obtained from any except the first appli-
5. The yield per acre decreased on all plots each year.
6. Better yields of Japanese cane will be obtained if the cane
is replanted every third or fourth year.

Fertilizer Experiment No. I was begun in the spring of 1914.
The variety of Japanese cane used in this experiment was S. P. L
No. 80464. The seed canes were planted January 7, 8 and 9,
1914, on acre 51 and 52 plot field. The cane was planted in rows
six feet apart and it required 2,182 whole canes to plant one
acre. The canes averaged about six feet long. In this experi-
ment there are twenty-three plots. One year's work with fer-
tilizer experiments is not sufficient to draw definite conclusions.
The following table gives the amount of fertilizer applied per
acre, the yield in tons of green material and the percentage of
sucrose in the juice. The canes grown on plots 14 to 23, inclu-
sive, were frosted before they could be harvested and weighed.
On this account the yield per acre is reduced somewhat.


Fertilizer applied per acre-pounds









------- ------

------ 30 load


------ check

110.------- ------
------- ------

------- ------
------- ------
------- ------

------- ------
------- ------
------- ------
------- ------
------- ------
------- ------

------- ------

2 --....
8 --....
4 -...
5 ----
6 --....
7 --..
8 ----
9 --....
10 --..
11 .--
12 ...
18 ...
14 ----
16 --
16 --
17 ----
18 --
19. ----
20 --
21 ----
22 ----
28 ----

- 150

- 150

- check
. chek











. .
..... .




















Annual Report, 1915

Date Harvested
Percentage May 8 July 6 July 20
Moisture ------------------ 11.62 10.21 11.57
Ash ------------- 5 .94 8.22 2.65
Protein --------------- 16.76 10.02 9.88
Crude Fibre ----------- -- 22.27 29.95 29.30
Starch and Sugar-.--------- 39.54 42.68 44.28
Fat ----------------------- 3.87 2.92 2.87

Maiden Cane Panicum hemitimomum is a grass that grows
in nearly all parts of Florida. It is usually considered more or
less of a pest. This is especially true when it appears in culti-
vated fields.
Table 15 shows the analysis at different stages of maturity.
This shows that during the early stages of growth maiden cane
is rich in feeding value. As it matures the percentage of crude
fiber increases and the percentage of protein and fat decreases.
These analyses indicate that maiden cane is one of the best
pasture grasses. It will also make a good hay. The chief diffi-
culty in using it for hay is that when it cures it turns nearly
black. For this reason it is not attractive and not readily mar-
keted, but the feeding value is not reduced.
Animal Industrialist.

Florida Agricultural Experiment Station

P. H. Rolfs, Director.
Srm: I herewith submit the report of the Plant Physiologist
for the fiscal year ending June 30, 1915.
During this year the study of the influence of fertilizers upon
the growth and health of citrus seedlings has been continued.
Experiments to determine the influence of certain sources of
ammonia and phosphoric acid upon the growth of seedlings
grown in a sandy soil have been completed. The data of these
experiments with brief discussions were published in the Annual
Reports of this Station for 1913 and 1914.* A review and fur-
ther discussion of these experiments is included in this Report.
Experiments to determine the influence of these sources upon
seedlings grown in a field soil have been completed in duplicate.
The data of the original experiment were presented in the An-
nual Report of this Station for 1914. (L c. p. xxxv.) The
duplicate of this experiment was completed during this fiscal
year, and is reported herein. But the results of these experi-
ments do not parallel. Since (1) the original experiment was
conducted during a different season of the year (July to Decem-
ber) ;** (2) the majority of the fertilizer combinations produced
less growth than that produced without fertilizer; (3) the
duplicate experiment was conducted during the spring season;
(4) practically all series of the duplicate experiment produced
more growth than that produced without fertilizer; and (5)
the results compare favorably with those obtained by growing
the seedlings in pure sand; it is to be concluded that the results
of the duplicate experiment are probably more indicative of the
influence of the fertilizer treatment upon the growth of the
seedlings; and that the effect of the fertilizer treatment in the
original experiment was modified by other factors.
In addition to these, sand culture experiments to determine
the influence upon growth of varying the quantity of the ferti-
lizers and their constituents as used in the above experiments
were carried out. The results of these experiments are not yet
*Fla. Agr. Exp. Station Annual Report 1913, p. xliv.
Fla. Agr. Exp. Station Annual Report 1914, p. xxxviii.
**The experiment was really concluded in June 1914, but it is only the
measurements made in December that are comparable to those of the dupli-
cate experiment. The greenhouse in which the experiment was conducted
was not heated, therefore the temperature variation was practically the
same as that outside the house.


Annual Report, 1915

available. These experiments will be duplicated during the com-
ing fiscal year.
Other sand culture experiments were carried out to determine
the influence upon seedling growth of ground limestone used in
varying amounts and in the absence of fertilizers; and to com-
pare the influence of equivalent amounts of nitrogen and phos-
phorous derived from steamed bone meal and from dried blood
and acid phosphate. The results of these experiments are not
yet available and will be reported in the Annual Report for the
coming fiscal year.
The study of the citrus disease Dieback has been continued,
and a number of co-operative field experiments for its control
have been arranged and begun. The data at hand have not
revealed the cause of this disease.

During the last three years fertilizer experiments have been
carried out in the greenhouse to compare the amount and char-
acter of growth produced by citrus seedlings when fed with vari-
ous sources of ammonia and phosphoric acid fertilizers. It is
assumed that this growth is, within certain limits, an indication
of the growth which these fertilizers will produce in citrus trees
growing in the field. This assumption is to be tested later by
field experiments.
The need for such experiments has been evident for a long
time. The fertilizers used in the citrus groves of this state cost
the growers hundreds of thousands of dollars. While there is
no doubt as to the necessity for the addition of the different fer-
tilizing elements-nitrogen, phosphorus and potassium-to prac-
tically all of the citrus soils in the state, there is a decided lack
of reliable technical information on the kinds, combinations,
amounts and time of application necessary to meet the maximum
needs of the citrus tree for growth and fruit production.
Fertilizer manufacturers make citrus fertilizers which consist
of mixtures of various sources of the fertilizing elements in such
amounts that these elements are present in certain definite ratios.
The composition of these brands has, for the most part, been
determined by grove experience. There is no doubt that these
brands when used consistently give satisfactory results. On
the other hand, the information is not at all definite as to (1)
what part each of these fertilizing elements contributes to the
growth of the tree; (2) what extent the effects of these elements


Florida Agrticultwra Exzpriment Station

are influenced (a) by each other and by other elements, (b) by
the sources from which they are derived, and (c) by the varia-
tion of the other conditions upon which growth depends; (3)
what ratios of the elements, what amounts of the sources and
at what time they should be added to the soil in order to meet
the maximum needs of the tree under various conditions, without
loss from the addition of insufficient or excessive amounts.
CONDITION AFFECTING GowTH.-Growth in the citrus tree
is the resultant of the influence of many conditions. The food
elements supplied to the tree comprise only one of these condi-
tions. Among others are temperature, light, air, moisture and
freedom from insects and diseases. In the production of growth,
each of these plays a part. The entire absence, or a sufficient
variation from the optimum, of any one or more of these condi-
tions will prevent or reduce growth, thus masking the good
effects of the other conditions. For example, no matter how
well fed the tree may be, no growth will occur if the temperature
is too low, or the soil in which the roots are growing is too dry,
or if the trunk is girdled by gummosis.
Of the several conditions which are necessary for growth of
citrus trees in the grove during the growing season, a number
of them, such as temperature and light, are fairly uniform.
Therefore, these would not be expected to mask the good effects
of feeding the tree well. On the other hand, a number of other
conditions such as soil moisture, may vary more or less
during this period. This variation may be sufficient to prevent
normal growth. It is a well-known fact that soil moisture con-
ditions vary considerably in the average citrus grove in Florida,
where proper cultivation or irrigation and drainage are not
practiced during the spring and summer months. This variation
necessarily reflects upon the growth of the tree. Other condi-
tions that may vary are other soil conditions and the presence
of diseases and pests.
CONDITIONs VARY.-It is, therefore, readily seen that if during
a particular season other growth conditions are favorable, a
given fertilizer may give good results; but if during the follow-
ing year, some one or more of the growth conditions vary
considerably, the same fertilizer may fail to give such good
results. In some cases the conditions that vary may be evident
and in others, obscure.
Experiments conducted in the grove to test the value of fer-
tilizer combinations must necessarily consider these growth con-


Annual Report, 1915

editions. Since it is not at all possible to control all of these
conditions in the grove, such experiments conducted during a
one- or two-year period are of questionable value. They must
extend over several years to obtain an average result which will
represent the true value of the particular fertilizer combination.
To determine more or less exactly the effects of the food ele-
ments upon the growth of the tree, the other growth conditions
must be controlled. The usual procedure for this purpose is to
grow plants in the greenhouse. But even in the average green-
house these conditions are only partly under control.
It is impractical to grow bearing citrus trees in the green-
house. Therefore, the plan of using seedlings for such fertilizer
experiments has been adopted. It is assumed that the growth
obtained from such experiments is an indication of the growth
that will be obtained under similar conditions in the field. This
assumption must necessarily be checked by field experiments.

During 1913 to 1915, series of experiments were carried
ried out in the greenhouse to compare the influence of various
sources of ammonia and phosphoric acid upon the growth of
grapefruit seedlings. These experiments mark the beginning
of an attempt to solve some of the problems concerned in the
nutrition of the citrus tree, which were discussed in the intro-
duction of this paper.
The first experiment was carried out in the spring of 1913,
and was reported in the Annual Report of this Station for that
year (I. c. p. xliv). The sources and amounts of the fertilizer
constituents used in this experiment are shown in Table 16.
These amounts were selected as a standard. Experiments to
determine the influence of variations of these amounts have
been partly completed and will be reported in the future.
The soil used in this experiment was a coarse white sand from
the shores of Lake Weir in Marion County. It contained little
or no organic matter. The results of this experiment are pre-
sumed to represent the growth influence of these fertilizer
sources and of their combinations when added to a soil lacking
During the spring of 1914, this experiment was duplicated
to see if the results would check during successive years. It was
found that they did check, but the total amount of growth made

Florida Agricultural Experiment Station

during the spring of 1913 was much greater than that made
during the spring of 1914.

I Sulph. Ammonia- Acid Phosph. H. G. Sulph. Potash ---------
5 grams 7.5 grams 2.5 grams
II Sulph. Ammonia- D. Bone B.--. H. G. Sulph. Potash --
5 grams 7.0 grams 2.5 grams
III Sulph. Ammonia- Basic Slag-- H. G. Sulph. Potash -- ----
5 grams 6.6 grams 2.5 grams
IV Nitrate Soda..-- Acid Phosph._ H. G. Sulph. Potash -
6 grams 7.5 grams 2.5 grams
V Nitrate Soda .-- D. Bone B.--. H. G. Sulph. Potash --
6 grams 7.0 grams 2.5 grams
VI *Nitrate Soda--- Basic Slag-__ H. G. Sulph. Potash---------
6 grams 6.6 grams 2.5 grams
VII Dried Blood-- Acid Phosph. H. G. Sulph. Potash ---------
5.5 grams 7.5 grams 2.5 grams
VIII Dried Blood--- DC Bone B.... H. G. Sulph. Potash ---------
5.5 grams 7.0 grams 2.5 grams
IX Dried Blood--- Basic Slag-__ H. G. Sulph. Potash----------
5.5 grams 6.6 grams 2.5 grams
X Nitrate Potash-- Acid Phosph.- None ------------- --------
7.5 grams 7.5 grams
XI Nitrate Potash.- D. Bone B.-.. None.------ ------ -----
7.5 grams 7.0 grams
XII Nitrate Potash-- Basic Slag.-- None-----------------------
7.5 grams 6.6 grams
XIII Sulph Ammonia- Acid Phosph.- H. G. Sulph. Potash- A. S. Lime
5.0 grams 7.5 grams 2.5 grams 9.0 grams
XIV Dried Blood-- .. Acid Phosph.. H. G.Sulph. Potash- A. S. Lime
5.5 grams 7.5 grams 2.5 grams 9.0 grams

XV None ----------- None-------- None ------------- A. S. Lime
9.0 grams
XVI Sulph. Ammonia- None-------- None ----------- ------
5 grams
XVII Nitrate Soda...-- None-------- None ------ ---------
6 grams
XVIII None ---------- None------- H. G. Sulph. Potash---------
2.5 grams
XIX No Fertilizer.--. (CheckSeries) --- ---- -- ----

*Not included in Sand Culture with Citrus Seedlings, 1913.
Sulph. Ammonia----------------------- Sulphate of Ammonia
Acid Phosph. -------------------- .-- Acid Phosphate
D. Bone B.---------- ------- -----Dissolved Bone Black
H. G. Sulph. Potash-------------High Grade Sulphate Potash


Annual Report, 1915


Average size of plant parts and average weights of plants produced by
the fertilizer sources and lime, used alone and in combination, and expressed
in millimeters and grams.*

i Cem
Series Length
No.t 1913 1914














~tem I
1913 1914

Leaf Leaf
Length Breadth
1913 1914 1913 1914

29.2 14.0
28.7 14.6
35.4 21.0

24.0 17.7
37.5 19.8
37.1 --

45.0 23.4
47.01 21.7
48.5 21.2

38.3 17.2
31.0 20.?
36.0 20.4

32.6 19.4
35.6 21.9

32.4 17.0
30.9 15.0
27.4 13.7
24.5 13.7

21.3 11.0

*This table is compiled from Table XV, Fla. Agric. Exp. Station An-
nual Report, 1913, p. xlv, and Table 22, Annual Report, 1914, p. xliv, and
includes the correction of certain errors which occur in these tables.
tSee Table 1 for the sources and amounts of the fertilizer constituents
applied to the different series indicated in this column.
**Owing to an accident to the material, the dry weights of the plants
of the 1914 experiment were not obtained.
***This series was lost from the 1913 experiment through accident.

1913 1914

1913 1914

; ~----


111 11



-I- I

xxxviii Florida Agricultural Experiment Station

Measurements of plant part relative to those of plants grown in soil
without fertilizer.*

Series Length
No. 1913 1914
163 113
II 168 103
m 288 140
IV 229 89
V 297 162.
VI -- 157
VII 359 217
VIII 303 196
IX 268 209
X 208 145
XI 278 141
XII 269 179
XIm 282 170
XIV 301 177
XV 190 156
XVI 172 138
XVII 154 122
XVIII 139 105
XIX 100 100

Stem Leaf
Diameter Length
1913 1914 1913 19141

Leaf Fresh
Breadth Weight
1913 1914 1918 1914

120 124
116 146
144 482
102 275
150 307
147 -
184 558
188 514
194 518
151 304
140 483
165 517
155 449
177 544
151 267
146 260
128 181
114 157
100 100

1913 1914

110 139 116
124 149 116
189 268 150
77 206 95
245 242 171
258 _-. 172
819 324 210
329 298 213
887 288 231
226. 207 163
202 279 149
306 280 190
i 1
244 267 171
326 299 196
258 193 169
240 177 156
132 146 118
142 135 115
100 100 100

General average 1913, 229; 1914, 161.
*The percentages shown in this table are based upon the measurements
shown in Table 17.
Tables 18 to 23 inclusive show the relative amount of growth
made by the plants of each series in comparison with those
which received no fertilizer. This amount is an average of the
relative measurements of the stem lengths, stem diameters, leaf
lengths, leaf breadths, and fresh weights for the 1913 and 1914
Experiments (1. c.).

-The general average of the relative growth of all of the
series (see Table 18) except the no fertilizer series, in the 1913
Experiment is 229. This average for the 1914 Experiment is
161. It is thus seen that the plants of the 1913 Experiment, as
a whole, made a much larger gain than did those of the 1914

Annual Report, 1915

A comparison of the absolute measurements for the two years
(see Table 17) shows that the plants of the no fertilizer series
of the 1913 Experiment made less growth than those of the 1914
Experiment. On the other hand, the maximum growth of the
1913 Experiment is much greater than that of the 1914 Experi-
ment. There is thus a much greater variation between the
growth of the no fertilizer series and that giving the maximum
growth in the 1913 Experiment than between the same in the
1914 Experiment. These variations indicate that the growth
conditions to which the plants were subject in the greenhouse
were not the same during the two years, and that those of 1913
were the better.
22 inclusive are arranged to compare the growth produced by
the different sources of ammonia when combined with the dif-
ferent sources of phosphoric acid and used in the amounts indi-
cated in Table 16. Table 19 compares the relative growth in-
duced by the different sources of ammonia combined with Acid
Phosphate and H. G. Sulphate of Potash. Excepting the nitrate
of soda series, and taking into consideration the difference in
amount of growth between the two years, it is seen that the
results are parallel. Since the nitrate of soda series in 1914 gave
less growth than no fertilizer at all, it appears likely that the
lack of duplication is an accidental variation. Dried Blood gave
by far the greatest gain. The Nitrates of Soda and Potash gave
the next best and averaged close together. Sulphate of Ammo-
nia gave the least gain.
Table 20 compares the relative growths induced by the differ-
ent sources of ammonia in combination with Dissolved Bone
Black and High Grade Sulphate of Potash. Dried Blood pro-
duced the best growth. The amounts of growth produced by the
Nitrates of Soda and Potash reverse but average intermediate
between Dried Blood and Sulphate of Ammonia. Sulphate of
Ammonia gave the least growth.

xl Florida Agricultural Experiment Station

Comparison of amount of growth produced by Acid Phosphate in com-
bination with various sources of ammonia relative to that produced by no
Acid Phosphate, H. G. Sulphate of
Potash plus 1918 1914 Average
Sulphate of Ammonia------ 139% 116% 128%
Nitrate of Soda -------------------- 206 95 150
Dried Blood -------------------- 324 210 267
Nitrate of Potash** --------------- 207 163 185
No Fertilizer -- ----------- 100 100 100
*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh
**No H. G. Sulphate of Potash was used in connection with this combi-
Comparison of amount of growth produced by Dissolved Bone Black
in combination with various sources of ammonia relative to that produced
by no fertilizer.*
Dissolved Bone Black, H. G. Sulphate of
Potash plus 1913 1914 Average
Sulphate of Ammonia.--------...... 149% 116% 133%
Nitrate of Soda ------------ 242 171 207
Dried Blood --------- --- 293 213 253
Nitrate of Potash** --------------- 279 149 214
No Fertilizer ------- --------- 100 100 100
*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh
**No H. G. Sulphate of Potash was used in connection with this combi-

Comparison of amount of growth produced by Basic Slag in combination
with various sources of ammonia relative to that produced by no fertilizer.*
Basic Slag, H. G. Sulphate of
Potash plus 1913 1914 Average
Sulphate of Ammonia ------- ------ 268% 150% 209%
Nitrate of Soda---------------------- -- 172 172
Nitrate of Potash**--------.--.---- 280 190 235
Dried Blood --------------------- 283 231 257
No Fertilizer --------- ------- 100 100 100
*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh
**No H. G. Sulphate of Potash was used in connection with this combi-

Annual Report, 1915

Comparison of amount of growth produced by Acid Phosphate and
Air Slaked Lime in combination with various sources of ammonia relative
to that produced by no fertilizer.*

Acid Phosphate, H. G. Sulphate of
Potash, Air Slaked Lime plus 1913 1914 Average
Sulphate of Ammonia ..----------. 267% 171% 219,
Dried Blood ------------ --- 299 196 24
No Fertilizer ------------------------ 100 100 100

*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh

Comparison of amount of growth produced by single fertilizer sources
relative to that produced by no fertilizer.*

Single Fertilizer Sources 1913 1914 Average
Air Slaked Lime--------------------. 193% 169% 181%
Sulphate of Ammonia --- ---------- 177 156 167
Nitrate of Soda--------------------- 146 118 132
H. G. Sulphate of Potash-------------- 135 115 125
No Fertilizer ----------------------- 100 100 100

*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh
Table 21 compares the relative growths produced by the dif-
ferent sources of ammonia combined with Basic Slag and High
Grade Sulphate of Potash. Owing to accident the Nitrate of
Soda series was lost from the 1913 Experiment. Dried Blood
gave the best growth. Nitrates of Potash and Soda gave the
next best growth, and Sulphate of Ammonia, the least.
Table 22 compares the relative amounts of growth produced
by Sulphate of Ammonia and Dried Blood when combined with
Acid Phosphate, High Grade Sulphate of Potash and Air Slaked
Lime. The Dried Blood series shows the best growth, but the
variation between the two during each year was not large-
only 32 points during 1913 and 25 points for 1914.
Table 23 compares the relative growths produced by Lime,
Sulphate of Ammonia, Nitrate of Soda and High Grade Sulphate
of Potash used singly and in amounts the same as used in the

Florida Agricultural Experiment Station

combinations. Lime produced the most growth; Sulphate of
Ammonia, next, and in amount not greatly different from Lime;
Nitrate of Soda was next, but the amount of growth was con-
siderably less than that produced by sulphate of ammonia. The
High Grade Sulphate of Potash produced the least. In all cases,
the amount of growth produced was greater than that which
was obtained where no fertilizer was used at alL
to 27 inclusive show part of the data in the preceding tables.
They are arranged to compare the growth produced by the dif-
ferent sources of phosphoric acid when combined with High
Grade Sulphate of Potash and the different sources of ammonia,
and when used in amounts as indicated in Table 16.
Table 24 shows the relative growths produced by the different
sources of phosphoric acid when combined with Sulphate of
Ammonia and High Grade Sulphate of Potash. Of these sources,
Basic Slag produced the greatest gain during both years. Dis-
solved Bone Black stood next, and Acid Phosphate produced the
least during 1913, whereas both produced the same during 1914.
The difference between the greatest and least gain was 129 points
during 1913, but only 34 points during 1914.
Table 25 shows the relative growths produced by the different
sources of phosphoric acid when combined with Nitrate of Soda
and High Grade Sulphate of Potash. The Basic Slag series of
1913 was lost through accident. In 1914, this series gave the
best growth by one point only. The Dissolved Bone Black series
was next in growth production in both 1913 and 1914. The Acid
Phosphate series gave the least gain for both years. However,
this series in 1914 produced less growth than the no fertilizer
series, which fact is probably due to some cause other than the
fertilizer. The difference between the greatest and the least gain
was 36 points in 1913, and 77 in 1914. It is probable that the
latter was much too large on account of the abnormal variation
of the Acid Phosphate series in 1914.
Table 26 shows the relative growths produced by the combina-
tion of the different sources of phosphoric acid with Dried Blood
and High Grade Sulphate of Potash. The Acid Phosphate com-
bination gave the best growth in 1913 and the Basic Slag in
1914. Dissolved Bone Black gave the intermediate growth dur-
ing both years. Basic Slag gave the least growth during 1913,
and Acid Phosphate the least in 1914.

Annual Report, 1915

Comparison of amount of growth produced by Sulphate of Ammonia
in combination with various sources of phosphoric acid relative to that pro-
duced by the use of no fertilizer.*

Sulphate of Ammonia, H. G. Sulphate of
Potash plus 1913 1914 Average
Acid Phosphate ------------------ 139% 116% 128%
Dissolved Bone Black--------. ----- 149 116 188
Basic Slag ---------------- 268 150 209
No Fertilizer ------------------.. 100 100 100

*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh

Comparison of amount of growth produced by Nitrate of Soda in com-
bination with various sources of phosphoric acid relative to that produced
by no fertilizer.*
Nitrate of Soda, H. G. Sulphate of
Potash plus 1918 1914 Average
Acid Phosphate --------- ....-----. 206% 95% 150%
Dissolved Bone Black--------- ----. 242 171 207
Basic Slag --------,------ -- ----------. 172 172
No Fertilizer --------------_------. 100 100 100

*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh

Comparison of amount of growth produced by Dried Blood in com-
bination with various sources of phosphoric acid relative to that produced
by no fertilizers.*
Dried Blood, H. G. Sulphate of
Potash plus 1913 1914 Average
Acid Phosphate -------------- 324% 210% 267%
Dissolved Bone Black-..-----__ 293 213 258
Basic Slag ------------------------- 283 231 257
No Fertilizer ---------------- 100 100 100
*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh


Florida Agricultural Experiment Station

Comparison of the amount of growth produced by Nitrate of Potash
in combination with various sources of phosphoric acid relative to that pro-
duced by no fertilizer.*

Nitrate of Potash plus 1913 1914 Average
Acid Phosphate --------------- 207% 163% 185%
Dissolved Bone Black ----------- 279 149 214
Basic Slag --------------------- 280 190 235
No Fertilizer -----------. 100 100 100
*The relative measurements indicated here are an average of those of
the stem lengths, stem diameters, leaf lengths, leaf breadths and fresh
The difference between the greatest and the least growth in
1913 was 41 points, and in 1914 it was 21 points.
Table 27 shows the relative growths produced by the different
sources of phosphoric acid combined with Nitrate of Potash.
The Basic Slag combination shows the greatest growth during
each year; the Dissolved Bone Black, the next; and Acid Phos-
phate the least The difference between the greatest and the least
growth was 71 points in 1913 and 41 points in 1914.
EXPLANATION OF VARIATIONS.-The difference between the
greatest and the least growth produced by the various sources
of phosphoric acid in combination with a given ammoniate, as
calculated from the averages shown in the last column in Tables
19 and 21, is as follows:
Sulphate of Ammonia --------------------81 points
Nitrate of Soda----------------------57 points
Nitrate of Potash ..-----------------------50 points
Dried Blood -----------------------------14 points
It is thus seen that the organic source of ammonia gives the
least variation in growth with the different sources of phosphoric
acid used; whereas, the mineral sources give much wider varia-
By referring to Tables 24 to 27, it is seen that Basic Slag, the
source of phosphoric acid which contains lime and has an alka-
line reaction, gives the greatest growth. Acid Phosphate, which
has an acid reaction, gives the least growth.
Referring to Table 22, where Sulphate of Ammonia and Dried
Blood are used with Acid Phosphate, High Grade Sulphate of
Potash and Lime, and comparing this with Table 19 where Sul-
phate of Ammonia and Dried Blood are used with Acid Phos-


Annual Report, 1915

phate and High Grade Sulphate of Potash without the lime,
and the following differences are shown:
1913-14 Difference
Sulphate of Ammonia-Acid Phosphate-------------128 points
Sulphate of Ammonia-Acid Phosphate plus Lime-_219 points 91 points
Dried Blood-Acid Phosphate-----------------.... 267 points
Dried Blood-Acid Phosphate-Lime--------------248 points 19 points
It is readily seen that the acid combination-Sulphate of
Ammonia-Acid Phosphate-High Grade Sulphate of Potash-
gives a growth which is not much greater than that of
the plants which received no fertilizer. The addition of
lime increased the growth to near the maximum. The addition
of lime to the combination of an organic ammoniate (Dried
Blood) with Acid Phosphate and High Grade Sulphate of Potash
resulted in no increase in growth.
By referring to Table 23 the average of the relative growths
produced by air slaked lime used alone in 1913 and 1914 is seen
to be 181. This average is much greater than the average rela-
tive growth of the Sulphate of Ammonia-Acid Phosphate-
High Grade Sulphate of Potash combination, which is 128, and
approaches that of the same combination plus lime, which is 219.

In conclusion, the following facts are true for this experiment:
(1) Dried Blood is superior to the other sources of ammonia
used in this experiment, for producing vegetative growth.
(2) The difference in amount of growth between the series
receiving Dried Blood in combination with the different sources
of phosphoric acid is small. The difference in amount of growth
between the series receiving the mineral sources of ammonia in
combination with the different sources of phosphoric acid, is
(3) Basic Slag produced a greater amount of growth than
the other sources of phosphoric acid which were used in combi-
nation with the mineral sources of ammonia.
(4) The acid combination, Sulphate of Ammonia-Acid Phos-
phate-High Grade Sulphate of Potash, produced the smallest
amount of growth of any of the combinations.
(5) The amount of growth produced by the acid combina-
tion, Sulphate of Ammonia-Acid Phosphate-High Grade Sulphate
of Potash, was largely increased by the addition of Lime. The
amount of growth produced by the combination, Dried Blood-

Florida Agricultural sEperiment Station

Acid Phosphate-High Grade Sulphate of Potash, was not in-
creased by the addition of Lime.
(6) The addition of Lime alone to the soil produced a growth
that was greater than that produced by the acid combination,
Sulphate of Ammonia-Acid Phosphate-High Grade Sulphate of
Potash, but not as large as that produced by this combination
plus Lime.
During 1914, a pot experiment was carried out to determine
the influence of the fertilizer sources and combinations shown in
Table 16 upon the growth of citrus seedlings grown in a field soil.
It was a duplication of the Sand Cultures with Citrus Seedlings
of 1913 and 1914, except that the soil used was a field soil instead
of pure sand. The results of this experiment were reported in
the Annual Report of this Station for 1914. (L c. p. xxxv). Dur-
ing the spring of 1915 this experiment was duplicated, and the
results are shown in Tables 28 and 29.
The 1914 experiment was started in July, 1913, and closed in
June, 1914; the duplicate experiment was started in January and
closed in June, 1915, when the first flush of growth was complete
and mature. The first flush of growth of the 1914 experiment
was matured in December, 1913. At this time, measurements
were made of the stem lengths, leaf lengths and leaf breadths of
the plants. These measurements are shown in Table 28. It is
only these measurements of the 1914 experiment that are com-
parable to those of the 1915 experiment.
A survey of the table shows that the results of the two experi-
ments are not parallel, therefore, the growth factors have not
been the same. In one or both experiments, the food factor has
not been the controlling one. Therefore, it is necessary that the
experiment be repeated. The tables showing the results of these
experiments are included in this report without any discussion.


Annual Report, 1915


Average size of plant parts and average weights of plants produced by
certain fertilizer sources and air slaked lime used alone and in combination,
and expressed in millimeters and grams.*

Stem Stem
Series Length Diameter
No.** 1914 1915 1914 1915
I 51.2 103.6 -- 2.6
II 51.7 106.2 2.6
II 58.5 97.7 -- 2.6
IV 61.4 88.6 __ 2.4
V 56.1 105.5 .. 2.6
VI 61.4 65.4 -_ 2.4

VII 49.7 130.5 --- 2.9
VIII 56.0 128.01 -- 3.0
IX 53.7 129.9 --- 3.1

X 63.9 93.0 -__ 2.6
XI 55.8 91.3 --- 2.8
XII 55.3 56.4 -- 2.3
XII 68.5 85.7 --- 2.4
XIV*** -- 117.0 2.8

XV 53.0 59.0 --- 2.3
XVI 56.6 91.3 -- 2.8
XVII 47.4 49.7 --- 1.9
XVIII 52.5 53.9 --- 2.3
XIX 65.5 54.7 -- 2.3

Leaf Leaf Fresh Dry
Length Breadth Weight Weight
1914 1915 1914 1915 1914 1915 1914 1915
84.5 49.0 16.5 23.81 2.3 -- .71
32.9 53.1 16.9 22.5 -. 3.0 .86
38.2 50.4 18.5 23.3 -- 2.7 .. .79
35.6 49.1115.6 22.5 __ 2.4 .60
31.4 50.9 15.0 23.4 -- 3.0 .79
31.3 35.2 13.0 18.0 --- 1.7 -- .50

33.8 56.9 16.4 25.4 --- 4.5 --- 1.70
36.5 58.2 18.6 26.0 --- 4.2 -. 1.40
34.2 57.9 16.7 25.9 .- 4.2 -- 1.50
35.7 47.3 17.2 21.8 2.5 .. .70
37.0 49.3 16.2 22.6 .- 3.0 .87
24.6 33.0 10.7 16.8 .- 1.4 .46
37.1 46.0 18.4 21.3 -- 2.3 .70

31.2 45.1 16.6 21.5 -- 2.8 .98
25.2 25.8 13.7 13.7 .. .7 .23
35.9 29.7 18.4 17.3 .-- 1.3 -- .41
34.4 30.9 17.6 16.5 .. 1.8 .45

*This table is compiled from Table 18 Fla. Agr. Exp. Station Annual Re-
port, 1914, p. xli, and unpublished data of the duplicate experiment con-
ducted during 1915.
**See Table 16 for the sources and amounts of the fertilizer constitu-
ents applied to the different series indicated in this column.
***This series was lost from the 1914 experiment through accident.
tThe 1914 experiment was started in July 1913 and closed in June 1914.
The measurements belonging to this experiment, which are shown in this
table, were made in December 1913. This was the end of the first flush of


Florida Agricultural Experiment Station

Measurements of plant parts relative to those of plants which were given
no fertilizer.*

Series Length
No. 1914 1915
I 78 189
II 79 194
III 89 179

IV 94 162
V 86 193
VI 94 120

VII 76 239
VIII 85 234
IX 82 237

X 98 170
XI 85 167
XII 84 103

XIII 105 157
XIV -- 214

XV 81 108
XVI 86 167
XVII 72 91
XVIII 80 99

XIX 100 100

Stem Leaf
Diameter Length
1914 1915 1914 1915








Leaf Fresh
Breadth Weight
1914 1915 1914 1915

1441 ---
136 -
141, --

142 ---
109 --
154 ---
158 -
157 ---

102 -


105 -

100 -

231 -

185 ---
230 ---

346 ---
323 ---
323 --

192 ---
231 ---
108 ---

177 ---
300 --

123 _-_
215 ---
64 ---
100 .

100 -

*The percentages shown in this table are based upon the measurements
shown in Table 28.
Plant Physiologist.

1914 1915


Annual Report, 1915

P. H. Rolfs, Director.
SIR: I hereby submit my annual report for the fiscal year
ending June 30, 1915.

(Anticarsia gemmatilis.)
This caterpillar is almost the only insect enemy of velvet beans
in Florida. Its ravages are often so severe as to discourage the
planting of velvet beans. The situation is rendered more serious
by the circumstance that velvet beans are very sensitive to
arsenic compounds. These considerations led the Department of
Entomology to take up the study of this insect.

Fig. 3. Moth of velvet bean caterpillar. (Anticarsia gemmatilis.)

The adult (Fig. 3) is a noctuid moth that makes its appearance
at Gainesville about the middle of August. The larvae usually be-
come abundant by the first of September. They have been found
feeding on only the various species and varieties of the velvet
bean (Stizolobium), the Kudzu vine, and the horse-bean (Can-
The egg is white until a day or so before hatching, when it
turns a delicate pink. It is nearly two millimeters in diameter,
and somewhat less in height. It is shaped much like the test of a
sea-urchin, and is prominently ribbed (Fig. 4).
The eggs are placed separately, usually on the under side of


Florida Agricultural Ezperiment Station

the leaves or on the tender shoots. They hatch in about three
days in September.
The young caterpillar makes its first meal from the shell of the
egg from which it has just emerged, usually leaving that portion
which is fastened to the leaf. It
then crawls to the lower surface of
the leaf from which it at once be-
gins to strip the lower epidermis
and mesophyll. This process is
continued until near the end of the
second instar when the caterpillar
begins to skeletonize the leaf by
eating all the soft material but
leaving the veins intact. After the
second instar it consumes the whole
Fig. 4. Eggs of Anticarsia. (Mag- leaf except perhaps the larger
unified 25 times.) veins and midrib.
It requires from three to four weeks to complete its larval life.
During this time it molts six times and passes through as many
instars. Late in the fall, a few individuals molted seven times.
The caterpillars are unusually variable in color and markings,
especially after the second instar. The majority show prominent
dark longitudinal lines and narrower ones of white, yellow or
pink on a ground of dark green. (Fig. 5.) On many, these
longitudinal lines are dim or even entirely lacking. These in-
dividuals are usually a light yellowish green but some are mahog-
any brown. In the following de-
scriptions both the dark and the -
extreme light forms are describ-
ed. It is not to be understood,
however, that there are two dis-
tinct types. All gradations of col-
or and markings occur. Further- Fig. 5. Larva of Anticarsia.
more a caterpillar that is pale
and without conspicuous longitudinal lines, may, in a later instar
show the markings of the dark type. For instance, in the follow-
ing pages the pale form of the third instar is described from the
same individual as the dark form of the fifth instar.

Annual Report, 1915

The newly hatched caterpillar (Fig. 5) is about 2.5 millimeters
(1-10in.) longandgrows to a length of 5 or 6 millimeters (1-5in).
before molting. As in all following molts there is a shrinking the
day before molting which amounts sometimes to as much as a
fifth of the length.
The head is light brown, rounded, bilobed; mouth shining and
light brown; eyes black. The body is a uniform light green, with-
out any trace of longitudinal stripes. The tubercles are black and
conspicuous. Of these, joint 2 (the one immediately behind the
head, the first joint of the thorax) has four on each side of the
median line and six on the cervical shield. Joint 3 has a row of
eight extending transversely across its middle, and one on each
lateral surface, more anteriorly situated. The two most dorsal
ones are small and almost touch at their bases, while the next
pair is very large. Joint 4 has a row of six tubercles on the
anterior portion of the dorsum and a pair on the posterior por-
tion, and, anterior to the latter on each side, there is a single
tubercle. On joints 5 to 13 there are two rows of tubercles, the
anterior row is curved, and the posterior straight. The setae are
The prolegs on joints 7 and 8 are about the same size, but are
much smaller than those on joints 9 and 10 and are not used for
walking. A glance at the prolegs is the most ready means of
determining whether a caterpillar is in the first or second instar.
The legs are light brownish yellow.
The caterpillar spends about two days in this instar. The aver-
age of twenty-seven individuals was 1.7 days.

The markings are now very similar to those of the next instar
but are somewhat less pronounced. The most conspicuous longi-
tudinal mark is the black border to the lateral line. The papillae
are black as in the first instar but there is around the base of
each a light-colored ring.
The first pair of abdominal prolegs, as in the first instar, is
less than a fourth as long as the third. They are weak and not
used in walking or clinging to the support. But the second pair
is about half as long as the third. These, too, are ordinarily not
used in walking but occasionally are.

lii Florida Agricultural Experiment Station

The larva spends three or four days in this instar (average
3.6 days) and increases in length from 5 to 9 millimeters (.2 to
.3 in.)
Darker Form.-Head rather square in outline, strongly bi-
lobed; yellowish; ocelli black; mouth dark brown. Body cylindri-
cal. All feet used for walking but the front pair may be some-
what shorter than the others, light yellow. Dorsal line pale white,
somewhat broken, margined on each side by a darker narrow
border. Sub-dorsal line very pale and indistinct, bordered below
by a continuous darker line and above by a similar but very faint
broken line. Lateral line indistinct and broken, narrow, pale
white. Substigmatal line wider and continuous but paler than
the dorsal and sub-dorsal. Ventral surface yellowish green.
Stigmata brown. Tubercles, black; dorsal and lateral surfaces
of joint 2 bear two rows of six each, and two others above the
legs; joints 3 and 4 bear ten tubercles in a straight row, the
second from the dorsal line being larger, another papilla above
the foot and one on the anterior border on a line with the spir-
acles; joints 5 to 12 bear two rows of papillae, six in each row,
also a pair on the sublateral region; joints 13 and 14 with four
papillae on each side. Feet light-brown. Setae long, black, stiff.
Pale Form.-Whole body of the caterpillar light yellowish-
green. Head light brown, mandibles dark brown. Dorsal line
represented by a very indistinct narrow line of a slightly paler
color than the surrounding skin, scarcely visible to the unaided
eye. Sub-dorsal line even more indistinct. There is no margin to
the dorsal line, but the subdorsal shows the dark fringe below.
The same is true of the lateral line. Sub-stigmatal line scarcely
distinguishable. Thoracic feet light brown. Both papillae and
setae are black.
This instar also lasts from three to four days during which the
caterpillar grows from an average of 9 millimeters to 15 or 16 in
length (.4 to .6 in.).
Head yellow, deeply notched, ocelli black, clypeus lighter.
Body green, yellowish behind. All feet used in walking, but the
second pair of prolegs and especially the first noticeably smaller
than the others.
Dorsal line white, broken, margined on each side by a dark
green border. Sub-dorsal and sub-stigmatal lines usually more

Annual Report, 1915

distinct than in the third instar. Otherwise this instar is colored
very much as is the third and like that has also light forms.
This instar averaged in our breeding records 3.7 days and in-
creased from between 13 and 16 millimeters to 18 millimeters
(.7 in.).
Darker Form.-Head wider than high; deeply notched above;
yellow, with brown reticulations on the sides and dorsal surface,
but not in front. There is an area in the middle of each lobe on
the dorsal surface that is clear brown.
Body slender; abdominal prolegs about equal in length, pink
at the tips; thoracic feet light brown. Dorsal line almost continu-
ous from joints 3 to 13, yellowish white; between the joints
changing to clear yellow and becoming much wider, its edge very
irregular in outline; bordered on each side by a heavy brown line
which is wider than the dorsal line; both dorsal line and border
very dim on joint 2. Area between dorsal and sub-dorsal lines
tan-colored, with a few white dots bordered with brown; one of
the largest of these dots is situated near the anterior border and
sub-dorsal line of each joint from 4 to 12, largest on joints 7 and
8, double on joint 4; they are placed more posteriorly on joints
9 to 11. There are three other paler dots on joints 5 to 7 and two
on joints 8 to 10. One or two of these white areas are situated
within the dark border of the lateral line. Papillae arewhite with
brown apexes. Sub-dorsal line similar to the dorsal line; the
brown border on the dorsal side narrower than the sub-dorsal
line, and that on the ventral side much narrower and broken;
but the area between this border and the lateral line is nearly as
dark as the border and together they make a wide conspicuous
brown line the length of the insect. All these lines become paler
posteriorly. Lateral line narrow and much broken. Stigmatal
line brownish yellow, broken, bordered with white on the ventral
margin. This border is wide and forms a sub-stigmatal line.
This white band expands and surrounds all the spiracles which
are light brown. The area between the border of the stigmatal
line and the lateral line is tan colored as is also the ventral sur-
face. Anal plate a yellowish tan color.
Green Form.--Head pale yellowish green. Body almost uni-
formly green, the only conspicuous stripe being the sub-stig-
matal line. Dorsal line from pearly white to yellowish green,
much broken and very narrow, scarcely visible to the unaided

liv Florida Agricultural Experiment Station

eye, little or no sign of a border. Sub-dorsal line similar. Stig-
matal line often a rich yellow, bordered by lines of deep pink,
both bands disappearing on joint 2; the pink border broken,
especially posteriorly and the dorsal one at all the spiracles. The
dorsal pink band is bordered in turn by a pearly white border
which is unbroken, extending above all the spiracles and around
those on joints 8 to 11; on joints 9 to 11 it breaks through the
stigmatal line and meets the similar pearly-white sub-stigmatal
line. In some specimens the skin of the caterpillar is quite trans-
parent, the tracheae being plainly visible. Their free ends can
be seen waving back and forth in the body fluid in unison with
the beating of the blood vessels.
This instar lasts three or four days. Before molting the cater-
pillar commonly reaches a length of 25 millimeters (1 in.).

Darker Form.-Dorsal line pure white to yellowish white with
pink blotches; almost or quite continuous, and rather wide in
places, but very irregular in its width. Area on either side dark
brown to almost black but dotted with the white spots as in the
fifth instar.
Sub-dorsal line white, narrow, broken. Lateral line similar,
but even more broken; represented in the middle of the segments
by from one to three large white marks, which are several times
higher than long and meet the white line above the spiracles.
Stigmatal line and borders as in the light form of the fifth instar
but the pink line is apt to be replaced by brown. The ventral
region dark brown. Prolegs brown.
Green Form.-Head green, concolorous with the body except
clypeus which is paler. Dorsal line narrow but expanded on
joints 5 to 12 into one or two narrow projections placed nearly at
right angles to the long axis of the body. On joints 6 and 7 there
are always two of these projections. Scarcely a trace of the sub-
dorsal or lateral lines but the dark area between them rather
conspicuous. Stigmatal and sub-stigmatal lines together make a
conspicuous line along the side; the sub-stigmatal pearly white,
the stigmatal duller white with a mere suggestion of yellow, bor-
dered on each side by a much broken pink line. Directly above
the stigmata is another white line bordered above by dark green.
Papillae all white; hairs golden brown, darker toward the tips.
The caterpillar spends from five to twenty days in this instar.

Annual Report, 1915

The longer periods are recorded in the late fall and early winter.
It attains a maximum size of from 38 to 48 millimeters (1J to 2
in.). Two days before spinning it ceases to eat and descends to
the ground and rapidly shrinks to an average size of 25 milli-
meters (1 in.). As its size diminishes its color changes greatly,
finally assuming a mahogany brown. Other color changes are as
Dorsal line light brown; scarcely lighter than the dorsal area;
dim and indistinct; bordered with darker brown; the transverse
projections are much lighter than the other part of the line.
Dorsal area mahogany brown with a few yellowish brown dots
and papillae of the same color, anterior marginsof the latter dark
brown to almost black and much wider than the posterior mar-
gins. Sublateral line similar to the dorsal in color. Lateral line
grayish. Stigmatal area grayish; streaked with short, broken,
mahogany colored lines, no yellow, pink, nor pure white. Sub-
stigmatal line nearly white. Ventral region olive green. Cervical
shield dark brown but cut by the dorsal line; anal plate some-
what lighter.

The pupa are brown, smooth and shining. The joints of the
abdomen are punctuated with fine dots which are particularly
numerous on the anterior halves of the joints. Head somewhat
pointed. At the end of the abdomen are three pairs of hooked
spines, one pair of which is much larger than the others. Length
18 to 20 millimeters (.7 to .8 in.), width 4 to 6 millimeters (.16 to
.25 in.) ; length from apex of the head to end of wing cases 11 to
12 millimeters (about 4 in.). The head is somewhat pointed. The
S ___pupa is light green until about 24
hours old.
The pupa is usually placed barely
underneath the surface of the soil,
but as there are usually many dried
leaves under the vines during the
*' season when the caterpillars are pu-
pating, the pupae are well hidden.
S____ The caterpillar makes a loose and
i 6. Pupa of Ant a frail earthen cell in which to pupate.
SFig. 6. Pupa o Anticarsia in itsb g
earthen celL (Fig. 6). In the breeding cages,

Florida Agricultural Experiment Station

and sometimes in the field this pupal cell is made of dried leaves
or omitted altogether. The time spent in the pupal stage aver-
aged between ten and eleven days in September. As the weather
became cooler with the advance of the season, this time was
gradually lengthened until those that pupated in November aver-
aged twenty-one days and two that pupated on November 20 and
21 respectively issued on January 7, 48 and 47 days respec-
Like the caterpillar, the moth also is unusually variable. The
ground color varies from a light, yellowish brown to ashen gray
or a dark reddish brown. The moths that emerged late in the
season showed a larger proportion of dark colored individuals.
The most conspicuous and characteristic mark of the color pat-
tern is a line that crosses both wings diagonally near the middle.
On the hind wings this line is somewhat nearer the base than the
tip of the wing, but on the fore wing it is placed on the average
about two-thirds the distance between the base and the tip. This
line runs nearly straight across both wings until it approaches
the anterior border of the fore wings when it bends to extend to
the extreme tip. Usually the middle of this line is a cinnamon
brown, edged on either side with dark brown or black. Some-
times these borders overrun the central brown streak so that the
line becomes a homogenous sooty black mark. Between this line
and the distal margin of the. hind wing is an S-shaped row of
spots. One or two of these spots about the middle are usually
larger. These spots are colored and bordered like the diagonal
line. Near the base of the fore wings there are dark wavy lines
and often a slate-colored, oval area along the anterior margin,
near the apex. Old, badly rubbed individuals are brownish yel-
low with the pattern almost obliterated. Usually, however, there
is at least a trace of the diagonal line.
Beneath, the wings are cinnamon brown with a sub-marginal
row of light spots and a median dark line. This color pattern is
less variable than that of the upper surface of the wings. There
seems to be no constant difference in color pattern between the
sexes. The moth measures from one and three-eighths to one and
three-fourths inches across the oustretched wings.
Neither the caterpillars nor the moths make their appearance
about Gainesville until August, and usually do not become suffi-

Annual Report, 1915

ciently abundant to cause material damage until the first of
September, although the velvet beans are apparently large
enough to be attractive as early as May. Therefore one of the
questions which has engaged our attention is: Where are the
insects from early December until August? There appeared to
be three possible answers. Stated in the order of their seeming
probability they were:
(1) The caterpillars and moths are present during at least
the spring and early summer but in such small numbers as to
escape notice; the former perhaps feeding on some wild legume.
(2) They remain in the pupa stage until late July or August.
(3) They die out each winter and come up from the south
each summer.
1. A careful search has been made during the past two sea-
sons for either the moths or the caterpillars during the first
seven months of the year. The fields and hammocks have been
carefully searched every few days and moth traps maintained at
night. Although the moths do not go to traps readily, a light trap
set during favorable nights in the fall usually catches a few.
This search has yielded uniformly negative results. Not a single
moth or caterpillar has been seen before the first of August, and
usually not until the middle of the month.
2. Hundreds of caterpillars were reared in the laboratory
during October and November with special care to protect them
from "cholera." These pupae and others collected from the field
were placed in an out-door insectary under as nearly natural
conditions as possible. The last moth to emerge from these pupae
came out early in January. All that remained after that date
failed to emerge at all, and investigation a little later showed
that they were all dead. Careful search through the velvet bean
fields in January failed to disclose any live pupae. The last moths
to be seen on the wing out of doors were flying late in December.
3. There seemed to be left only the third possibility. This
led to an investigation of the insect's distribution and dates of
appearance in other localities. There was little found on this
subject in literature. Holland in "The Moth Book" gives the dis-
tribution as the "Mississippi Valley." Dyar in his list gives it as
the "Atlantic States." More than fifty circular letters were sent
out to students of lepidoptera in the Eastern United States. Most
of them replied. To sum up the answers we get the following
results. No one north of the Gulf States had seen the larvae.
The moths have been taken as far north as Ontario; but with

Iviii Florida Agricultural Experiment Station

one exception all of these moths captured in the North were
taken during the last days of September to November. The moths
have not been taken in the New England States and appear to be
more common in the Ohio Valley directly north of Florida than
at corresponding latitudes on the Atlantic Coast or in the Prairie
States. All of the letters indicate that Anticarsta is but a stray
wanderer in the northern states, like the cotton caterpillar's
moth (Alabama argillacea). Professors Newell of Texas, Hinds
of Alabama, and Worsham of Georgia answered that they had
never observed the caterpillars on velvet beans in those states.
Professor Newell wrote: "Velvet beans are quite extensively
raised in Texas but I have never noticed caterpillars nor had any
complaints." Prof. Ellison A. Smyth of Blacksburg, Va., who has
paid especial attention to this family of moths (Noctuidae),
wrote, "I have also been collecting in the neighborhood of
Charleston, S. C., off and on for many years and have never seen
it there."
As compared with these records from the North, those from
South Florida are very instructive. The insect begins to do seri-
ous damage in the Miami section in July, at least six weeks
earlier than at Gainesville.
On June 30, 1915, the writer found the moths in a velvet bean
patch at Winter Haven. The moths were badly rubbed, indicating
that they were old. They were not at all abundant. No larvae
were found nor were there any indications of their work on the
velvet beans. The moths had evidently just arrived. In an
equally careful search at Tavares the next day no traces of the
insect were found, and a very careful and extended search at
Gainesville on July 2, likewise yielded negative results.
DISTRIBUTION.-The following data from the manuscript of
the List of Florida Lepidoptera by the late Mr. Grossbeck were
supplied to me by Mr. Frank E. Watson of the American Museum
of Natural History: "The moth was taken at South Bay, Lake
Okeechobee, April 29 and 30. Extends northward to Staten
Island, westward to Wisconsin and Texas and southward through
Mexico and the Antilles to South America." It does not seem,
however, to be at all abundant in the West Indies. Several corre-
spondents in Porto Rico report that it is not troublesome there
or that they have never noticed it. It is not listed in the List of
the Noctuidae of Panama. There is a wild species of Cannavalia
in South Florida that could well be its original host plant as well
as that of another species of the same genus, A. ferruginea, Sm.

Annual Report, 1915

It seems therefore almost certain that the moth is a migrant
in the northern states and that it does not ordinarily winter over
even in the central parts of Florida, but works northward each
summer from South Florida where one or more of its host plants
are available for food at all seasons. It seems to be a sub-tropical
insect which is ill adapted to regions of frost.
With us, however, it is not the direct action of the cold that
exterminates the insect. On November 21, 1914, the thermom-
eter on the Station grounds sank to 22, which is considerably
lower than that recorded at any time during an average winter.
Yet pupae lying exposed on the surface of the ground were not in-
jured and a number of moths were seen inthefields a few days later
when the weather had moderated. The factor that prevents their
enduring even the moderate winter at Gainesville is their imper-
fect hibernation. A few warm days in winter causes the moths
to emerge from the pupae; while the absence of food plants, and
perhaps the scarcity of mates in the case of those that remain
longest in the pupae, result in their death without progeny. If
the moths could remain in the pupae until April or even as late
as March, they would before death find suitable host plants in
many cases.
After the freeze of November 20, 1914, which killed their
observed host plants, attempts were made to raise the caterpil-
lars on some of the wild and cultivated legumes from the fields
and hammocks. Although the caterpillars ate sparingly of some
of these plants (alfalfa was one of the least disliked) they did
not grow and undoubtedly would have died had not some velvet
beans been raised in the greenhouse for them.
LIFE OF MOTH.-Their ability to reach such far northern sta-
tions as Canada is explained by their longevity. Some moths,
kept in a cage 4 by 4 by 5 feet and fed on moistened sugar, lived
five weeks. Although apparently capable of prolonged journeys,
the moths as observed in the field, do not ordinarily take long
flights. They hang about the velvet bean plants closely, coming
out for short flights about sunset. If disturbed, they dart away
rapidly but usually fly only a few yards and do not rise high
above the vines. If unable to find the food plants of the larvae
on which to deposit eggs, it is possible that they may fly long dis-
tances, as is the case with the cotton caterpillar, Alabama argil-

Florida Agricultural Experiment Station

Although they lived so long in outdoor cages, we were, with
one exception, unable to get moths hatched in the laboratory to
breed in confinement, even when given a cage 6 by 7 by 5 feet.
One female only in this cage laid a few eggs. Because of this
failure to get the moths to breed in confinement we were unable
to determine the number of eggs that a female will lay. Females
caught and carried into the laboratory laid readily even in small
breeding cages. Some laid as many as twenty eggs in a single
night. We observed none of the insects mating, either in the
laboratory or in the fields. Mating undoubtedly takes place at
night. There is no suggestion of definite broods at Gainesville.
The moths seem to arrive in small numbers from the south dur-
ing August, and at any time after late August one may find all
stages in the field on the same day.
As to the number of generations in a year, nothing definite can
be said because of their absence during seven months of the year
and the uncertainty of the age at which egg-laying begins. The
first moths to reach us have time to rear four generations in
Gainesville provided they begin to lay eggs within a few days
after emerging. At that rate, were they to remain here for a full
year, they would probably produce nine generations. Perhaps
that many are produced in the southern part of the State.

Some determinations were made as to the amount of food the
caterpillars normally consume. In all cases they were well fed
at the beginning of the experiment, so that the amount should not
be far from that normally consumed in the field. The leaves were
weighed before feeding and again at the end of the experiment.
In the meantime they were kept under a bell jar with their stems
in a bottle of water, so that there was practically no loss of
weight from evaporation. From October 19 to 21, twenty-two
caterpillars weighing 4.8 grams ate 17 grams of leaves of velvet
beans in 52 hours, i. e. they ate an amount equal to their own
weight at the beginning of the experiment in less than fifteen
hours. The 17 grams represented about 980 square centimeters
(over 1 square foot) or about four large leaflets.
Another lot of fifty-three caterpillars weighing 8 grams ate
24.5 grams of leaves in 48 hours. They ate the equivalent of
their own weight in less than 16 hours. These caterpillars were
in the fourth to sixth instar. Younger ones, although they would

Annual Report, 1915

eat much less in proportion to their numbers, would eat much
more in proportion to their weight.
No canibalistic tendencies were observed even when the food
was exhausted in cages where many caterpillars of different
sizes were confined together. In this respect they differ markedly
from some other noctuids such as Heliothis. From the stand-
point of the grower this is unfortunate.
These caterpillars, as usual, cease eating for about twenty-
four hours before molting. After the molt is completed, the first
meal of the fresh caterpillar is invariably the cast off skin, which
is usually completely consumed except that of the anterior por-
tion of the head including the eyes. This habit rendered great
care necessary in working out the correct number of molts as the
small fragment of cast off skin is easily overlooked.

The caterpillars have many natural enemies. One of the most
important is the "Rice bird" (Agelaeus phoeniceus), also called
"Blackbird", or "Red-and-buff-shouldered marsh blackbird."
These birds congregate in the infested fields in great flocks com-
posed largely of immature individuals. Other birds, especially
mocking birds, eat many of the caterpillars. Lizards, especially
the "Chameleon" (Anolis), feed eagerly upon them. Wasps carry
off a great many with which to store their nests to provide food
for their young. Among the important insect enemies are pre-
daceous bugs of several species which are common in velvet bean
On the other hand, neither the caterpillars nor the pupae suffer
much parasitization by hymenoptera. Of the hundreds of pupae
reared in the laboratory from material collected in the field, none
showed such parasites, while from a hundred pupae collected in
the field, only a single parasite was raised, a chalcid. Dragonflies
capture a good many of the moths.

By far the most efficient check on the increase of this pest is
a disease called "Cholera" by the farmers. This is caused by the
fungus Botrytis rileyi. In October, 1914, this fungus nearly ex-
terminated the caterpillars in the fields about Gainesville. Very
much less than one-tenth of one per cent escaped. On the Station
grounds, where they were so exceedingly numerous as to destroy

Florida Agricultural Experiment Station

much of the fields, the caterpillars became very scarce in a week.
This is not unusual. On the contrary it is of almost yearly occur-
rence. Sooner or later the fungus gets started, and practically
exterminates the pest, but too often it comes too late to save the
velvet beans. After once becoming established in the field, the
fungus seems always to hold the insect down for the remainder
of the season. The fields apparently become so thoroughly in-
oculated with the spores of the fungus that a caterpillar can
hardly escape infestation sometime before it has time to com-
plete its growth. Indeed, in our life-history work, it was neces-
sary, after the appearance of the disease, to feed the caterpillars
in the laboratory on leaves collected from vines that had never
been infested with caterpillars. The first symptoms of the dis-
ease is the emaciated appearance of the caterpillar which clings
motionless to the leaf and refuses to eat. It finally elevates the
anterior end of the body and
dies in that position. (Fig. 7).
It does not show a tendency
to climb to the highest part
of the vines, as do many oth-
er species of caterpillars when
parasitized. A few hours later
the surface of the body be-
comes covered with the dirty
gray hyphae of the fungus. If
Fig. 7. Caterpillar killed by "Cholera" the dead caterpillar is removed
Natural size. at or before this stage, oth-
ers in the cage usually do not
contract the disease. Twenty-four hours later the dead cater-
pillar turns white, owing to the maturing of the spores of the
fungus. If allowed to reach this stage in a cage with live cater-
pillars, all of the latter will usually die of cholera within three
days. Three days then would appear to be the length of time
necessary for the fungus to kill the caterpillar it infests. We see,
therefore, how cholera can spread so rapidly through a field. A
large number of these mummified caterpillars was kept over win-
ter and an attempt will be made the coming season to start an
epidemic during the caterpillar season.
We have introduced from Massachusetts eight pairs of the
carabid beetle, Calosoma sycophanta. This bettle, originally in-
troduced from Europe, is reported to be doing good work in
Massachusetts against the caterpillars of the gypsy moth. It is

Annual Report, 1915

hoped that they will become established in Florida where they
should be of much benefit in helping to control not only the velvet
bean caterpillar, but others as well. As they climb readily they
should be able to live on the tent caterpillars, Heliothis, and

Fig. 8. Velvet beans damaged by larvae of Anticarsia.

others early in the season before Anticarsia appears. We are
attempting to breed them in the laboratory so as to get a larger
number for liberation and also to work out their life-history
under Florida conditions.
A number of substances were tried in an attempt to find a
more satisfactory insecticide for this pest. The lime-sulphur-lead
arsenate spray previously developed (See An. Rp. 1913) again
controlled the outbreak when it was applied in time. It does not,
however, kill all of the caterpillars, owing, doubtless, to the small
amount of lead-arsenate which can be used without seriously
burning the plants. Be-
l cause of the long tangled
vines, the crop is a diffi-
S- cult one to spray. A dust
Fig. 9. Fifth Instar Caterpillar. which can be applied with a


lxiv Florida Agriutural Experiment Station

"blower" without killing the vines is to be desired and further
attempts will be made to find such a substance.

A study of the life-history of the Florida flower thrips and the
character and extent of the damage it does to three types of vege-
table products was undertaken:
(1) Deciduous fruit trees and their blossoms, chiefly peaches,
pears and plums, in the late winter and early spring.
(2) Blossoms and young fruit of citrus trees, in the spring.
(3) Blossoms of tomatoes in the summer.
The insect has been going under the name of the Grain Thrips
(Frankliniela tritici, old Euthrips tritici), but a careful com-
parison with the original description of the northern grain thrips
and with specimens collected in North Carolina resulted in the
discovery that ours is not the same insect. We have not seen the
typical F. tritici in Florida, although we have obtained it from
Atlanta, Ga. Consequently our insect was described under the
name F. tritici projects. It was thought best to describe it as
a variety of the other until it could be determined whether or not
intermediate forms occur. The most conspicuous and constant
anatomical difference is in the second joint of the antenna which
is asymmetrical and much prolonged in ours. Our insect seems
to average a little larger and to bear more orange pigment.
The discovery that our insect is not identical with the north-
ern type, gives us an opportunity to discard the old common
name, "the grain thrips," which has always been misleading, as
the insect is not at all characteristic of grain. The northern type
received its name tritici, because it was first found on wheat.
This was a mere accident. Indeed, unless in bloom, grains and
grasses are, of all vegetation, the place where one is most apt not
to find this insect. The grain thrips with us are Anthothrips
floridensis, Frankliniella fuscus, and Aeolothrips bicolor.
Although it is occasionally taken almost anywhere out of doors
and even flies into our dwellings,-this insect is distinctly a flower
inhabiting species. From flowers the adults get their food; in-
flowers they find shelter from their enemies and the weather;
on flowers they mate and lay their eggs; and on flowers the young
develop. Indeed, it would seem that the entire life-history is
passed in flowers. It was thought that they might retire into the
ground during the coldest part of the winter but we could find

Annual Report, 1915

no evidence in favor of this assumption. They are decidedly less
in evidence during the coldest days but that seems to be due to
their greater sluggishness. They retire into the depths of the
flowers and lie quiet. A careful search of the flowers during some
of the coldest days in winter always revealed their presence.
Although occasionally taken in almost any flower, they have
their decided preferences as to both color and structure of the
blossom. Roses are favorites and we find more individuals m
white than in red ones when the two are growing together.
Roses supply them with plenty of soft tissue for food and among
the dry petals and stamens they find excellent hiding places in
which they can avoid the sun. They are decidedly negatively
phototactic to the direct rays of the sun, although positively
phototactic to diffuse daylight, such as that coming from a win-
dow. Citrus blooms are also great favorites, and tomatoes are
well liked. In each case the stamen mass affords ideal shelter as
well as food. They prefer dry flowers, and those with a long tube
filled with nectar such as honeysuckles and phlox are distinctly
avoided. On the other hand those with a wide dry tube such as
petunias, wistarias and Scutellaria are the first choice. On these
flowers they are much more abundant in proportion to the size of
the blossoms, than on roses or citrus. In the autumn the dry
tubes of the Compositae are much frequented. Naturally a blos-
som that hangs on the plant for some days becomes more heavily
infested than one that is evanescent. The insects are given more
time in which to find the former. They seem to have some pre-
ference for white, yellow or light blue blossoms over darker ones.

Prof. A. L. Quaintance worked out the life-history of this in-
sect which he found severely damaging strawberries at Lake
City in April, 1898. His results were published in Bulletin 46
of this Station. Although the insect is there named Thrips tritici,
the cuts which are evidently reproductions of photographs enable
us to identify the insect as this variety. Quaintance gives the
time spent in the different stages as follows: Egg, 3 days; larva,
5 days; pupa, 4 days; total life-history, 12 days. This account
leaves several points to be cleared up, some of which we succeeded
in working out. The data in Bulletin 46 seems to have been
gathered from limited material. The average time taken for some
thousands of eggs to hatch in April was three days. A dozen or
so hatched when only two days old and some hundreds required

lxvi Florida Agricultural Experiment Station

four days. Quaintance's period of twelve days for the entire life-
history we found to be somewhat below the average of our in-
sects which were raised in the laboratory in test tubes during
April and May. Although a number in our tubes completed their
entire development in ten days, the average was fifteen days.
A number required eighteen days, and one required twenty-four
days. Since the age at which adults begin to lay eggs must be
considered in any estimates of the time taken to produce a gener-
ation, some experiments were conducted to determine this age.
We found that while many began to lay eggs when three days
old and a few even earlier, most of them did not lay many eggs
until the fifth day. This would indicate that about twenty days
is the average time required to produce a generation. At that
rate there would be time for eighteen generations during a year,
but the rate of reproduction is undoubtedly much slower in win-
ter and may cease altogether. We found no young out of doors
until March 1 this year. There are, however, probably a dozen
generations in a year.
The adult lives longer than one would expect of such a small
delicate insect that passes through its early stages so rapidly.
In our breeding cages, where conditions, especially those of
moisture, were abnormal, some lived twenty-two days. One
female lived twenty days during March under a lantern globe on
an out-door pear tree. Here conditions were more nearly normal
although the moisture was excessive. Under natural conditions
it is probable that they may live much longer, especially in the
winter. If they do not breed during the coldest weather, the
adults must live for a considerable time out of doors, as it is as
adults that they live over. Owing to the delicate and evanescent
character of the tissues in which most of the eggs are laid, it is
not probable that the insect lives over in that stage.

On pears, peaches and plums there are two types of injury.
The insects may attack the unfolding buds and deform the leaves,
or they may attack the blossoms or young fruit.
In investigating this subject we collected thrips and liberated
them on inclosed buds or blossoms. Other buds were inclosed
for checks. For this purpose we used at firstthinparaffined paper,
but this tore too easily, particularly after a rain. We then tried
glass cylinders made from large test tubes out of whichthebottom
had been melted. Cotton was stuffed into the open ends of these

Annual Report, 1915

cylinders. These glass cages were carefully shaded from the sun
by pieces of paper or cloth. These worked better but there was
considerable condensation of moisture on the inside of many of
them. Sometimes the thrips were drowned in this moisture.
We finally found lantern globes most satisfactory. We pre-
vented the escape of the insects from the larger end by first ty-
ing a piece of cheesecloth over the opening and then stuffing it
with cotton, working from the inside; or we used two pieces of
cheesecloth with cotton between. The cotton was necessary to
prevent the thrips from escaping. It also allowed considerable
moisture to escape, and prevented largely the undesirable con-
densation on the inside.
We liberated under each of these cages from ten to fifty thrips
caught on different flowers. The high mortality among these
insects was due partly to faulty ventilation and other unnatural
conditions, and partly to the old age of the thrips. Many of the
cages, however, after two or three weeks contained old and young
thrips, showing that the insects could breed in the cages. This
was also true in the cages that contained leaf buds only. Hence
blossoms, although preferred, are not absolutely necessary for
development. After the foliage was killed the insects died. They
are not able to live on the green bark of deciduous trees as the
camphor thrips lives on its host plant.

The buds and blossoms on which we liberated'but ten thrips
gave uniformly negative results. On many of the leaf-buds in
the cage in which thirty or forty were liberated there were dis-.
tinct signs of injury. This injury was characterized by dwarfed
and deformed leaves, caused by the feeding and egg punctures
made on the tender foliage of the developing bud. This sort of
injury did not occur in any of the check cages.
This type of injury is similar to that described by the writer
as inflicted upon camphor by the camphor thrips, and to that
described by several authors as caused by Euthrips pyri in Cali-
fornia. There was little of this injury seen on the trees in the
orchard. This indicates that thrips must be abundant to cause
much injury of this type.
Doubtless the unfolding buds are a second choice as feeding or
breeding grounds and will be used extensively only in the ab-
sence of blossoms or in case of an unusual abundance of thrips.
Blossoms of the trees were inclosed in the same sort of cages


Florici A_ cuWtuhd' E~peipment Station

'and treated in the same manner. The insects preferred the bases
of the petals as feeding grounds, but the few eggs found were
on the bases of the calyces inside. Later in Wistaria, from which
we gathered many thrips for our experiment, a similar condition
was observed. On the petals which we pulled off, few or no
larvae developed. From the ovaries and the receptacles of these
same blossoms we obtained thousands of larvae. The instincts
of the female evidently impel her to oviposit in the more endur-
'ing parts of the flowers and to avoid, for that purpose, the more
evanescent petals, even when the latter are being used largely
-for food. Thus we see that the insect through its instincts is
well adapted to life on blossoms.
The results with the blossoms paralleled those with the buds.
If only ten or even twenty thrips were introduced, little or no
harm resulted. If more were used the blossom usually fell off.
In the orchard there were not enough thrips to do perceptible
As a summary of the year's experiments and observations on
these deciduous fruit trees we find that, if sufficiently abundant,
the Florida flower thrips will cause the deformation or even the
destruction of leaves and fruit. The general character of the
injury is similar to that described for the pear thrips. However,
the damage actually caused in the groves near Gainesville was
In a paper read before the Florida Horticultural Society in
April, 1914, Mr. Ira Soar of Dade City describes severe injury
to these fruits that year. Similar observations are recorded in
Bulletin 46 as observed by Quaintance at Lake City in 1898. The
numbers of thrips vary greatly from year to year and from
month to month. This variation is probably due in part to
weather conditions, dry weather seeming to favor their increase.
Furthermore, many observations of the writer on citrus and
tomatoes during the last three years would indicate that during
late winter and spring at least, these insects are more numerous
in the southern part of the State than at Gainesville. This may
be due to a check on growth and reproduction induced by the
cooler weather at the latter place.
In the orange and grapefruit bloom the favorite feeding place
is on the inside of the cylindrical column of stamens. Next the
succulent petals are chosen. 'A limited amount of feeding on


Annual Report, 1915 lxix

these evanescent organs probably does little harm. But if the
insects are abundant the tissue of the receptacle about the base.
of the ovary is attacked and then the ovary itself. It is in the
receptacle also that most of the eggs are laid and here the larvae
can often be found feeding after both stamens and petals have.
fallen and most of the adult insects have flown to more inviting,
fields. If sufficiently injured, this receptacle turns yellow and
finally causes the bloom to drop. As the orange tree generally:
produces an abundant bloom, much of which will necessarily
drop, there has been doubt in some quarters as to the actual
amount of damage the insects do in a grove. Some investigators
have even expressed the opinion that thrips are on the whole
beneficial in a grove in that they carry pollen from one blossom
to another.
An opportunity was afforded at Winter Haven to carry out.
some co-operative experiments. On April 1 an unusually, heavy
infestation of thrips was discovered in that community. In the,
groves of Mr. J. B. Scott and Dr. McLean there was an average,
of about 75 insects in each old bloom. Many contained 150 by
actual count, one 286, and one more than 400. In blossoms that
had been open but a short time the insects were not so abundant.
The owners of the groves had been spraying with lime-sulphur-
to control citrus scab and were about to give the trees another
application. Consequently the tobacco extract (2.7% nicotine):
was added to the lime-sulphur in the proportion of one part to
100 of the lime-sulphur. The latter tested 30 degrees Baume
and one part was used in sixty-five of water, which was the:
strength that had been used to control scab. The trees were in:
full bloom and the spray was driven directly into the bloom. They
spraying was thoroughly done by an experienced crew. It was-
estimated that at least 90% of the thrips were killed. A heavy
dropping of bloom was reported a few days later, but these were
apparently blooms that had been injured by the insects, although
it is possible that the spray did some injury. In Mr. Scott's grove
three rows were left as a check and an unsprayed adjoining
grove served the same purpose. The trees in these two groves
were of the same age and had been given the same treatment.
In fact they had formed a single grove until a year previous.
The trees were five years old and in prime condition, compara-
tively free from whitefly and scale. Most of them had an abund-
ant bloom. In the McLean grove we were able to obtain only
two trees as checks.

Florida Agrieultural Experiment Station

EFFECTS OF SPRAYING.-On April 22 the groves were again
visited and in the Scott grove careful counts made of the amount
of fruit on both the check and adjacent sprayed rows. On the
whole number of trees on which the fruit was counted there was
about 50% increase in the sprayed over the unsprayed trees. Fur-
thermore, a larger percentage of the sprayed fruit had a healthy
look. It was larger and of a deeper green than the unsprayed.
Much of the latter was yellow, which indicated that the dropping
due to thrips injury was not yet completed.
It was thought that the amount of bloom on a tree might be
a factor in determining whether or not spraying for thrips would
be profitable. It was conceivable that thrips might be beneficial
by thinning the fruit on trees overloaded with bloom; or perhaps
the dropping they caused would be inconsequential, because of
the overblooming. On the other hand, the same percentage of
injury on a tree with scanty bloom might seriously lessen the
crop. Accordingly the trees on the three check rows, and those
on the three adjoining rows, were divided into three classes;
those with light bloom, those with heavy bloom and those with
fair bloom; and the fruit of each class counted separately. Seven
sprayed trees with light bloom had an average of 252 oranges,
while three trees in the check row averaged 58. This gives an
increase of 334% in favor of spraying. Of those with fair bloom,
seven sprayed trees average 380 fruits per tree, while five un-
sprayed trees averaged 250, which gives an increase of 52% for
spraying. Nineteen sprayed trees with heavy bloom averaged
660 oranges per tree, while eighteen unsprayed trees averaged
390, an increase of 69% for spraying. These trees had been set
only four years. Although the numbers counted are too small
for definite conclusions, they would indicate that thrips are rela-
tively more important when the bloom is light than when it is
moderately heavy. The figures for medium and heavy bloom
would indicate some difference in favor of the latter, but they
should probably be interpreted as indicating little difference.
The apparent advantage is within the limits of probable error.
The grove was again visited June 29. Early in May there-had
been heavy dropping of fruit. Carefuil counts were made of the
amount- of'fruit on the check rows and on three adjoining sprayed
rows.' Fifty-one trees in the check.rows averaged 66.5 fruits
per areei and lo'rty-ight- trees in the adjoining sprayed rows
averaged 'IA-:, ah incea~-iif only 7.4%.
When the trees with light bloom were segregated as before,' the

Annual Report, 1915

following results were obtained: Eight trees in check rows that
were formerly credited with light or medium bloom averaged
126 fruits, while twelve trees in the sprayed rows with a similar
bloom averaged 215 fruits, an increase of 70%. It should be
noticed that these trees that had a light bloom averaged more
fruit than those that had carried a heavy bloom. This is prob-
ably due to the fact that the former were near the east ends of
the rows where the trees were larger and healthier than the
average for the six rows.
The trees with a heavy bloom gave an average increase of
7.3% for the sprayed trees.
On the grapefruit trees in the upper part of the grove where
the trees were a year older, there was noticeably more fruit than
in the adjoining grove. But as the latter had not received ex-
actly the same treatment, it could not be used as a check in a
rigid scientific experiment and no counts were made.
Although this increase is small it undoubtedly paid for spray-
ing even on the trees with a heavy bloom.
It was a little early to make final observations on the amount
of marked fruit. However, the counts on the check rows gave
50% of thrip-marked fruit as compared with 10% on the sprayed
Further search for Cryptothrips floridensis in different parts
of the State was carried on as opportunity offered. The results
tend to confirm the previous conclusion that the insect is absent
from Gainesville and from most of the northern part of the
State except at Satsuma. In the Annual Report for 1913, its
known distribution is given. Since then we have found it in no
new location in Florida but have received it from the late Profes-
sor Rutherford of Ceylon. Both its limited distribution in Flor-
ida and its presence in Ceylon would indicate that the insect is
not a native of Florida. Although we have searched diligently,
we have not found this species on any other host.
The life-history was worked as far as the gross outlines gre
concerned, on insects kept throughout the year in the laboratory
and insectary.
The eggs are laid mostly in the buds of the leaf axils. They
hatch in about a week. The young, first stage, larvae are pale
straw color with a few dark lines about the head, but after molt-
ing they become orange colored,.with heads, antennae, prothorax


Florida Agricltural Ezperiment Station

and legs of dark brown or black. The young require about two
weeks to complete their growth. After two or three days in the
pupal stage, the adults appear. The entire life-history requires
about twenty-four days. Some adults lived three weeks under
a bell jar in the laboratory. Out of doors they would probably
live longer under favorable conditions,
The extent to which they use their wings is a point of con-
siderable importance in relation to their rate of dispersal.
Their dispersal in the field would indicate that they are
spread mostly by horses and men during cultivation. They
spread much more readily along the rows than from, one row
to another. They have never been observed to fly or even to
spring in the field. Poking with a bristle and other means that
will usually cause other species of thrips to take to wing were
tried in vain.
Nine of these thrips were placed under a bell jar without food.
A small bottle of water into which were placed the stems of some
twigs of camphor was placed under the bell jar. The bottle and
the inside of the bell jar were banded with vaseline to prevent
the thrips from crawling up to the camphor or to the top of the
bell jar, from whence they might drop to the camphor. After
forty-eight hours only one thrips had reached the camphor. Sev-
eral had crossed the band on the bell jar and it was possible that
the one on the camphor had crossed one of the bands.
It is evident that the camphor thrips seldom if ever uses its
A black thrips, identified as an undescribed species of Antho-
thrips, to which the writer has given the name A. floridensis,
was common during March on the blooms of some Mexican ava-
cados, most of which they ruined. They attacked the stamens
and pistils in a manner similar to that of the Florida flower
thrips. A few of this species were also taken from strawberries
and citrus.
The summer of 1914 was abnormally dry throughout most of
Florida. As a result entomogenous fungi did not thrive. Con-
sequently there was a large fall brood of whiteflies followed by a
heavy growth of sooty mold. There was a good growth of the
brown fungus in September in many parts of the State and con-
siderable of the red, but in general, where insecticides were not
applied, they did not prevent a large spring brood of whitefly.:


Annual Report, 1915

The rapid increase of whiteflies following a season unfavorable-
for the entomogenous fungi demonstrates the immense import-'
ance of these fungi in controlling the pest during normal years.
In the home grove on the Station grounds the trees were heav-
ily infested and very black with sooty mold in the fall, but a
severe freeze in November defoliated practically all the citrus
trees except some of the sour oranges. As a result the new
growth of the present season is quite free of whitefly.
The same condition prevailed in Graves' Satsuma grove. In
Hampton's (now Watts') grove the cold did not do nearly so
much damage. The majority of the leaves did not fall. The
whitefly was abundant and blackened the trees markedly. There
was considerable brown fungus in September and October 1914,
but the amount was not sufficient to control the whitefly.

Some further experiments were tried in the summer of 1914,
with the red Aschersonia which had been kept dry over winter.
It was the intention to make comparisons between the "catches"
obtained from dried, cold storage, and fresh material, but the
cold storage material met with an accident in the cold storage
plant and was lost. As a result we were able to compare only
the dried and fresh material.
In July 1914, equal numbers of pustules of the dried and fresh
material were placed in separate pans of water and whitefly in-
fested twigs were dipped in the water. The dried material had
been kept in the laboratory from the previous October. From
the fresh material we obtained in all cases a good "catch," but
from the dried a much poorer one. We obtained about 100 times
as many pustules from the fresh material as from the dried
This dry material was not so satisfactory as that used last
year because it had been kept longer.

In October 1913, the Station began to receive complaints of
Icerya purchase at Key West, whence they had probably been
carried by boat from Tampa or St. Petersburg. They were first
noticed in Key West about July 1913. The case was represented
as so serious that in July 1914, the entomologist visited the
island after stopping at Leesburg and Winter Haven to collect.

Florida Agricultural Experiment Station

some Vedalia. About sixty were obtained and liberated in the
cemetery at Key West which seemed to have about the heaviest
infestation of Icerya.
The infestation was severe throughout the city but there was
little to be found in the native growth at the east end of the
island. One of the favorite host plants was the "Gumbo Limbo,"
Burseria simaruba, a tree that grows thirty or forty feet high,
with a trunk more than a foot in diameter. From some of these
trees it would have been possible to pick a bushel of Icerya. The
insects hung in hand-full masses on all the limbs and even the
trunks. Many of these trees were dead and others were dying.
The entomologist spent two days on the island determining the
host plants and distribution of the scale. The following hosts
are arranged in the approximate order of severity of infestation.
Those marked with an asterisk are not recorded in Riley's list
(Rep. U. S. D. A. 1880, p. 491) or in Mrs. Fernal's (Hatch Exp.
Station Bulletin 88).
*Gumbo Limbo (Burseria simaruba) ; Citrus, all species. Many
dead; Roses (Rosa sp.); *Coleus; Spanish Lime; *Rosa-de-Mon-
tana (Antigonon leptopus); *Sheperds' Needle; Grape (Vitis
sp.); *Solanum Blodgetti, Chapman; *Tecoma; *Cenchrus gra-
cillimus, Sand spur; *"Logger-head Breast"; *Banyan; Fig;
*Sapodillo; Bougainvillia; *Fox-tail grass; *Paradise tree (Sim-
arouba glauca); Sunflower (Helianthus sp.); Pomegranate;
*Royal ponciana (Ponciana regia); *Spanish Mulberry (Calli-
carpa americana L); *Ilex Kingrana; *A palm; Poinsettia;
*Australian Pine (Casuarina equisitifolia) Beefwood; *Cocoa-
nut palm (Cocos nucifera), nuts only; *Sedum sp.
The importation of Vedalia was a marked success. About
three months after its introduction a correspondent reported that
Icerya was becoming noticeably scarcer, especially in the vicin-
ity of the cemetery and that the Australian Lady Beetles were
spreading all over the city. Meanwhile the city authorities had
imported other colonies which helped to reduce the infestation.
In January 1915, it was reported that the scale was not much
in evidence.
While collecting the Vedalia at Winter Haven an interesting
phenomenon was observed. On the majority of the trees all the
Vedalia were in the same stage of development. On some trees
only adults were-found; on others only pupae; on some only
young larvae; and on others only larvae nearly full grown. The
explanation seems to be that on eachttree the Vedalia were-the


Annual Report, 1915

young of a single female and had hatched from a single litter
of eggs.
An observation at Leesburg suggests that Vedalia will fly a
considerable distance. Mr. Widner has a grove on the north
shore of Lake Griffin. Early in 1914 Icerya was sent in from
there. The grove was visited in July 1914. Abundant remains
of the scale were found on two or three trees adjacent to the boat
landing and a few scattering remains on surrounding trees. But
the scales were mostly dead. No living Vedalia could be found
although the trees were littered with empty pupa cases. Mr.
Widner stated that the tree with the heaviest infestation was
one under which some sacks of fertilizer from Leesburg had
been piled and several empty sacks were still there. The history
of this infestation seems to be: The Icerya was undoubtedly car-
ried to the grove by boat from Leesburg and developed a flour-
ishing colony before the Vedalia arrived. Had the Vedalia ar-
rived with the scale, the latter could not have developed such a
large colony. The Vedalia probably found the colony by a flight
of between two and three miles from Leesburg. There was no
colony closer. The adjoining groves have neverbeen infestedwith
the scale. Doubtless when their only food, the cottony cushion
scale becomes scarce, these beetles will fly several miles in search
of it. In this case they apparently flew across Lake Griffin in a
single flight. The only other possibility is that they were car-
ried by boat, or carriage around the Lake. It is not likely, how-
ever, that an insect so restless as the adults of this species would
cling to a small boat or a carriage long enough to be transported
that far.
Up to June 1, 1915, when this topic was turned over to the
newly created office of Entomologist to the Plant Board, we had
recorded, during the year, the following new localities for this
insect: Miami, March 1915; Auburndale, March 1915; Tavares,
April 1915; Parrish, Manatee County, April 1915; Kissimmee,
May 1915.
The Woolly Whitefly ('Aleurothrixus howardi) received con-
.siderable attention in the way of new localities and percentages
of infestation with its parasite. The results were incorporated
in Bulletin 126.

Florida Agricultural Experiment Station

The Green Shield Scale (Pulvinaria psidii) also called the.
Mango Scale and the Guava Scale, received some attention at
Miami in July. It was found severely infesting the Wild Rub-
ber Tree (Ficus sp.) and to a less extent the mango and to a still
less extent the guava bushes. These, with an occasional light
infestation of citrus, seem to be its host plants in Florida. This
scale is heavily preyed upon by a predaceous caterpillar and by
trash bugs (Haemorobus sp.) as well as lady beetles.
The California Red Scale (Chrysomphales auranti) was again
sent in from Cocoa in December 1914. It was collected by Mr.
F. M. O'Bryne in a grove several miles from the other infesta-
tion. This scale seems to have established itself at Cocoa, con-
trary to our previous experience with it in Florida.
The tomato fruit worm (Choridea obsoleta, or Heliothis obso-
leta) was made the subject of some control measures. It was
found that sweet corn if in full silk, acted as a trap crop and
lessened injury to adjacent tomatoes. We found also that when
the tomatoes were small we could poison about 50% of the worms
with one application of lead arsenate. These results were in-
corporated in Bulletin 125 on tomato insects published during
the year.


Annual Report, 1915

R. H. Rolfs, Director.
SIR: I submit the following report of the Plant Pathologist
for the year ending June 30, 1915.
During the last year, work on Citrus Diseases has been con-
fined chiefly to Citrus Canker, Gummosis and Melanose. Al-
though Gummosis was the major problem as outlined at the be-
ginning of the year, investigation of this disease has been lim.
ited in a measure owing to the increased demand for informa-
tion on Citrus Canker. The major part of the work during the
season has been confined to this disease.
Active work on the vegetable diseases has been resumed. This
phase of the work has been taken up by Dr. C. D. Sherbakoff,
who came to us last August.
A preliminary study of a new or little known pecan disease
has been made during the year and has been carried on chiefly
by Mr. J. Matz.
Work on Gummosis the last season, though limited, has been
carried on along the same lines as followed the previous year,
namely, field observations, infection, and control, experiments.
FIELD OBSERVATIONS.-In general the disease has not seemed
so severe the last season as in the two preceding years.
While many new cases of the disease have been observed, badly
infected trees show a better general condition and a tendency to
recover from attacks. This may be only a temporary condition,
marking a quiescent period of the disease, that is due to seasonal
Observation on the development of diseased areas was con-
tinued with about the same results as reported previously. (Rept.
Fla. Expt. Sta. 1914, p. lxi.)
INOCULATION EXPERIMENTS. Five series of inoculations
were reported in my report for last year. The fifth series was
made in bearing trees in a grove at Crescent City. Final notes
on these were taken in February of the present year, fourteen
months after the inoculations were made. Since Gummosis is
slow in development it seemed advisable to keep these inocula-
tions under a long period of observation before drawing any
final conclusion. All the inoculations made in this series gave
negative results, in so far as producing typical Gummosis infec-


lxxviii Florida Agricultral Ezperiment Station

tions were concerned. In a few cases there was a slight gum-
ming and a small amount of tissue killed at the point of inocula-
tion, which was at first considered suggestive of infection. These
healed completely later without further development; and in no
case were diseased areas, resembling Gummosis areas, that de-
veloped under natural conditions, produced.
A sixth series of inoculations was made in January 1914 in
bearing orange and grapefruit trees at Weirsdale, Fla. The
details are given below.
Series VI. Large bearing trees. This grove has been badly
infected with Gummosis for several years. It was planted
chiefly to orange, trees; however, a number of rows of grape-
fruit trees are scattered through the grove. In this particular
grove the disease is probably more severe on grapefruit trees.
The trees in this grove were killed back during the freeze of
1894-5 and a majority of them at present have multiple trunks.
In this series the inoculations were made in trees that were
infected with Gummosis. However, trunks and limbs were se-
lected that showed no indications of disease at the time. The
area of inoculation was first washed clean with water, then with
an alcoholic solution of corrosive sublimate and allowed to dry.
A small cell of putty was built up on this, exposing at the center
a surface of clean bark about 1 inch by I inch. The surface of the
area, thus enclosed, was slightly scraped with a flamed scalpel,
and a small slit was made through the bark down to the wood.
The material used for inoculation was introduced into this slit
with sterile instruments and the wound pressed together. The
inoculations were made under as nearly aseptic conditions as it
was possible to obtain under field conditions. Immediately after
inoculation each cell was sealed with a microscopical slide. The
cells and slides were removed about one month later.
Forty-five inoculations including fifteen checks were made in
six trees. Seven inoculations were made with diseased tissue
taken from an active gumming area of the Psorosis type of gum-
ming; seven with tissue taken from an active area of the Gum-
mosis type; eight with spores and mycelium from pure cultures
of Diplodia natalensis, and eight with spores and mycelium from
pure cultures of Phomopsis citri. Fifteen checks were made
that received the same treatment except that no fungi or tissues
were introduced. The inoculations and results are summarized
in Table 30.

Annual Report, 1915


Inoculated R M S d t 0 Results
with A. *

Psorosis tissue -----. 0 4 0 3 0 7 Negative
Gummosis tissue---.1 1 3 0 2 7 Negative
Diplodia natalensis -- 1 2 1 2 2 8 Negative
Phomopsis citri ------ 1 2 2 2 1 8 Negative
Checks ------- 1 5 1 3 4 2 15 Healed
All the above inoculations finally gave negative results. In
no case were typical symptoms of the disease produced. Some
of the inoculations as well as a few of the checks gummed slightly
for a time and in a few cases there was a slight killing of tissue
around the point of inoculation, but all finally healed without
further development.
Thus far all inoculations in connection with Gummosis have
given negative results. In no case have the characteristic symp-
toms of the disease been produced artificially. But these results
can hardly be considered as final proof that the disease is not
transferable to healthy trees. A majority of these inoculations
have been of a preliminary nature, and more work in the grove
with bearing trees is necessary before any definite conclusion
can be reached. It is evident that the disease spreads among
the trees in the grove under natural conditions. This has been
confirmed by observations made the last three years on a block
of one hundred and eighty trees. The trunks and larger branches
of each tree in this block were carefully examined for Gummosis
and all diseased trees recorded. The first inspection was made
in the spring of 1913, and eighty trees were found infected. In
the spring of 1914 the trees were again inspected and ninety-six
infected trees were noted, an increase of fifteen over the pre-4
vious year. In the spring of 1915 a third inspection was made
and one hundred and twenty infected trees were found. This
gives a total increase of 21% in two years.
CONTROL EXPERIMENTS-Experiments for control of Gum-
mosis have been carried out along with the other work on
this disease at Weirsdale. In the report of last year the results
of some preliminary experiments were given which indicated
that Bordeaux Paste and Carbolineum may prove effective in
keeping the disease in check, if all the infected tissue is first
removed and the wound painted with one of these antiseptics.


Florida AgiculturWl ERperiment Station

Last season a more extensive experiment along this same line
was begun. A block of 120 bearing orange and grapefruit trees,
72 of which were infected with Gummosis; was selected for the
The experiment was carried out in two series. In one, the
surfaces of the diseased areas were merely scraped to remove
fragments and scales of bark. In-the other the diseased areas
were carefully cut out and all dead and diseased tissue down to
the healthy wood was removed. The entire trunks of all trees
in this block, healthy and diseased, were then painted with the
antiseptics, from the ground to two and one-half to three feet
high. The following preparations were used as antiseptics.
Bordeaux Paste. (California Formula). Prepared as follows:
1 pound of Copper Sulphate.
Two pounds of fresh slaked stone lime.
It gallons water.
The copper sulphate is dissolved in 1 gallon of water. The lime is slaked
in a half gallon of water and allowed to cooL The copper sulphate solution
is then added to the slaked lime and the mixture sirred to a thin paste.
Apply with a brush.
Lime and Sulphur Paste. Prepared as follows:
1 part of flour of sulpur.
2 parts of air slaked lime.
Water to make a thin paste. Apply with a good brush.
Commercial Lime-Sulphur Solution:
1 gallon of the concentrated solution.
9 gallons of water.
This can be applied with a brush or with a small bucket spray pump.
In Table 31 is given a summary of the experiment and the
results of the last season.

I No. Dis-
Antiseptic Trees eased Areas Active New Per ct.
treated trees treated areas areas healed
Bordeaux Paste ------ 20 15 49 38 27 25
Lime & Sulphur Paste- 20 12 21 17 I1 19
Con. Lime-Sulph. 1 to 9 20 10 31 26 10 19
No. Dis-
Antiseptic Trees eased Areas Active New Per et.
treated trees treated areas areas healed
Bordeaux Paste ---- 20 15 49 23 10 58
Lime & Sulphur Paste. 20 i 11 29 16 13 45
Con. Lime-Sulph. 1 to 9 20 9 30 11 18 68


Annual Repott, 1915

The above results can only be considered as tentative. The
peculiar nature of the diseased areas in apparently healing or
remaining quiescent for a time and then becoming active again
makes it difficult to tell whether a wound has permanently healed
or not. When the above notes were taken and especially in the
series where all the diseased tissue was removed before treating,
all areas were considered active that had spread since treatment
and showed gum flow at the time of the final observations. New
areas were easily detected. All areas which showed a circle of
new cambium around the wound and which had not spread or
gummed since treatment were considered healed. Where the
surfaces of the diseased areas were merely scraped away it was
a more difficult problem to distinguish between the active and
healed areas. However, the greater part of the areas thus
treated showed a considerable scaling and spread after treat-
The same treatment was repeated on the above trees this
spring and the experiment will be carried through another
The pruning experiment for the control of Melanose, begun
at East Lake in 1913, was continued during last season. The
results obtained from last season's work are very favorable to
careful pruning for controlling Melanose. Infection was much
heavier in this grove during 1914 than in the preceding year.
Thus the inspection of the 1914 crop of fruit from the experi-
mental plot did not show as high a percentage of bright fruits
from the different blocks as in the previous year. However, the
ratio of percentage of bright fruits between the check and
pruned blocks was greater than in 1913.
A few slight changes were made in the method of grading the
fruit this season in order to facilitate the work in the field. The
grade, culls, has been omitted. All unmarketable fruits were
formerly assigned to this grade, which was composed chiefly of
small sizes, imperfections and injuries other than Melanose, ex-
cept in cases where the entire surface of the fruit was involved.
Since the culls formed a very small percentage of the total out-
put and had little or no direct bearing on the experiment, they
could be dropped without affecting the results as far as Melanose
spottingwas concerned. Otherwise the fruitwas classedabout the
same as given in the last report. Under "Brights" were classed

lxxxii Florida Agricultural Experiment Station



1- n ~~-
- 12""

Annual Report, 1915 lxxxiii

8 -


lxxxiv Florida Agricultural Experiment Station

all fruits entirely free from Melanose or those that showed less
than one per cent of the surface spotted. The "Seconds" included
all fruits showing from 1 to 25 per cent of surface spotted. Under
"Russets" were classed all fruits showing from 25 per cent to
entire surfaces spotted. Anything classed as a cull was dis-
carded. These grades apply to Melanose spotting only.
As a basis for the future grading of fruits during the experi-
ment, photographs were made of fruits representing the ex-
tremes in each of the different grades. These are shown in the
following cuts:
A. and B. represent the limits of fruit clased as "Brights."
(Fig. 10).
B and C represent the limits of fruit classed as "Seconds."
(Figs. 10-11).
C and D the limits for "Russets." (Fig. 11).
The grading of fruits from each block was done by the same
person so that the results from the different blocks are compar-
able. The percentages of the different grades from each block
of the 1913 and 1914 crop are given for comparison in Table 32.
In the table representing the 1913 crop the figures have been
modified to exclude the culls and the prcentages are based on the
total fruits of the three grades from each block.

1913 CaoP or Faurr
No. of i Percentage of
Block Trees When pruned Brights Seconds Russets
No. 1 12 Check 23 74 3
No. 2 16 Jan. and June 47 52 1
No. 3 10 January 40 57 3
No. 3* 6 January 56 43 1
No. 4 12 June 34 62 4
1914 CaoP or FRIrr

No. of Percentage of
Block Trees When pruned Brights Seconds Russets
No. 1 12 Check 12 73 15
No. 2 16 Jan. and June 35 60 5
No. 3 8 January 34 63 3
No. 3* 8 January 56 41 3
No. 4 12 June 45 53 2

*Carefully pruned by the writer. Care was taken to remove the smallest
dead twigs.

Annual Report, 1915

The demand for information concerning Citrus Canker has
called for a large amount of work during the last season, and
the major part of the investigation on citrus diseases was cono
fined to this disease. This work has been chiefly in the nature
of a laboratory study of the disease and such field studies and
observations as time and opportunity permitted.
Citrus Canker is one of the worst plant diseases that has ever
appeared in the State. Its virulent nature and the rapidity with
which it spreads called for vigorous and immediate action in an
effort to control it. Early attempts to control the disease by the
ordinary methods employed against plant diseases proved futile,
and it was soon decided to completely destroy the tops of all
infected trees by burning them in the grove where they stood.
This method has been followed vigorously since last August and
at present is being continued in an effort to completely eradicate
the disease.
The peculiar nature of Citrus Canker and the character of the
infections have been the cause of misleading conclusions even
among plant pathologists. (1)
Within the last three months the writer has had to change his
views entirely regarding the cause of this disease. Citrus Can-
ker was generally accepted as a fungus disease and had ap-
parently been proved to be such. Recently Miss Clara H. Hasse
of the United States Department of Agriculture published an
account of her work on this disease in which she demonstrated
that Citrus Canker is a bacterial disease, caused by Pseudomonas
citri Hasse, which is described as a new species. Through some'
experiments of my own and independently, I had come to the
conclusion that Citrus Canker was a bacterial disease, two days
before I heard of Miss Hasse's report. The results from more
recent experiments with this organism confirm Miss Hasse's
work and prove to my own satisfaction that Pseudomonas citri
is the primary cause of this disease.
(1) Stevens, H. E. Citrus Canker. Fla. Agrl. Expt. Sta. Bul. 122, 1914.
Stevens, H. E. Citrus Canker. Ann. Rpt. Fla. Expt. Sta., 1914.
Stevens, H. E. Citrus Canker II. Fla. Agrl. Expt. Sta. Bul. 124, 1914.
Edgerton, C. W. Citrus Canker. La. Agrl. Expt. Sta. Bul. 150, 1914.
Wolf, F. A. and Massey, A. B. Citrus Canker. Ala. Agrl. Expt. Sta.,
Cir. 27, 1914.
Hasse, Clara H. Pseudomonas citri, the Cause of Citrus Canker, Dept.
of Agr.; Jour. of Agr. Research, April 1915.


lxxxvi Florida Agricultural Experiment Station

I have not been alone in the belief that Citrus Canker was a
fungus disease and my former statements published regarding
the cause were not based merely on guess work. The data at
hand at the time (though it has since been proved faulty) seemed
to warrant the conclusion drawn. Other pathologists working
on this same disease, independently and during the same period,
also came to the conclusion that the disease was of fungus
origin. Wolf and Massey (2) in May 1914, stated that Citrus
Canker was caused by a species of Phoma. The following is
quoted from their work under the heading, Cause of the Disease:
"Several different fungi have been found associated with the spots and
cankers, but it has been determined that the disease is caused by a species
of Phoma. Since several different species of Phoma have previously been
reported on Citrus, the specific name remains to be determined only after
further study. This Phoma has been isolated in pure culture from grape-
fruit leaves and twigs, from Citrus trifoliata twigs, and from Satsuma
leaves. Inoculations have been made with pure cultures into grapefruit
twigs and leaves and into the twigs of Citrus trifoliata. The inoculations
made on grapefruit twigs and leaves on April 23d had developed the char-
acteristic symptoms of the disease by May 12th. The fungus fruited on the
artificially inoculated trifoliate twigs about two weeks after the date of in-
oculation and the Phoma has been reisolated. It exhibited the same appear-
ance and characteristic growth in culture as the organism originally isolat-
ed, which was used in making these inocualtions. This leaves no doubt that
the Phoma, which is being studied, is the cause of the disease."
Edgerton (3) in October 1914, refers to Citrus Canker as a
fungus disease and points out the possible connection between
this disease and one reported from Brazil on Citrus, which was
described by Noack (4) as caused by DidymeUa citri. Edgerton
apparently made no study of Citrus Canker.
On several occasions I have stated that this disease was caused
by a fungus and some explanation of these earlier conclusions
.seems necessary. In a preliminary bulletin issued in March
1914, I suggested that a species of Phyllosticta might be the cause
of the disease. Later in the Annual Report of June 1914 I stated
that Citrus Canker was caused by a species of Phyllosticta and
that this had been demonstrated by infection experiments. In a
paper read before the Citrus Seminar the following September,
this statement was repeated and infection experiments were
cited to support this theory. This paper was later published
as a part of Bulletin 124. On other occasions since I have ad-
vanced the fungus theory and even as late as April 1915 I read
2 l.c.
3 I.c.
4 Noack, F.; Pilzkrankheiten der Orangenbaume in Brasilien, Zeit. f.
Pflanzenkrankheiten, Vol. X, pp. 824-827. 1900.

Annual Report, 1915

a paper before the Florida State Horticultural Society in which
the cause of the disease was ascribed to a species of Phyllosticta.
Immediately following this meeting I discovered my error and
the paper was corrected with a statement to that effect.

Citrus Canker was recognized as a new disease to Florida
when it was first called to our attention and it has since proved
to be entirely new to science. No reference to this disease or
one with similar characters could be found in a search of all the
available literature on Citrus Diseases. Its economic importance
and virulent nature were not at first suspected, and it was only
given minor attention at the time. The general appearance of
the disease and the character of the infections are more suggest-
ive of fungus origin than bacterial. This opinion prevailed
largely with the writer when the disease was first brought to
his attention and no doubt this has had some influence on the
results obtained. No bacterial disease had ever been reported
on Citrus in Florida, and since no bacterial disease of importance
occurred on the Citrus group, the citrus tree was looked upon
generally as immune to bacteria.
In the preliminary work on this disease a number of different
fungi and bacteria were found associated with the spots and
cankers. This was not considered unusual, for the ruptured sur-
faces and spongy interior of canker infections form an easy
means of entrance for invading fungi and bacteria.
Infection was first transferred to healthy grapefruit foliage
by contact with dried leaf specimens of the disease that had been
kept in the laboratory for nearly one month. This indicated the
infectious nature of the disease and was more suggestive of a
fungus origin than bacterial.
A fungus, having the character of a Phyllosticta was finally
isolated from very young canker spots and further investigation
showed this fungus somewhat constantly associated with spots
and cankers of the disease. On potted trees in the greenhouse
and citrus foliage in the open this fungus was found abundantly
in canker spots that had been produced by contact with diseased
specimens. Specimens examined from different localities in
Florida and from other states showed the presence of the fungus
in a majority of cases. Thus the reasonably constant associa-
tion of this fungus with canker infections from widely separated


lxxxviii Florida Agricultural Experiment Station

areas and the fact that it had been isolated from the tissue of
young canker spots, suggested it as the probable cause of the
Cultures of the fungus were obtained from single spore col-
onies for infection work. Care was taken to select spores from
a single pycnidum and after sowing in cornmeal agar the posi-
tion of a number of spores was located and marked. The fungus
grows rapidly on cornmeal agar, producing visible colonies in
36 to 48 hours, and pycnidia are formed at the surface of the
agar in from 5 to 7 days after planting. Sub-cultures were made
from several of the marked colonies on sterilized orange sticks.
These were kept along with the cultures isolated from young
spots. All these cultures exhibited the same growth characters
and appeared to be identical morphologically. One of the cul-
tures from a single spore colony was used for infecting Citrus
foliage as a preliminary test of the fungus. A small tree in the
greenhouse was sprayed with a suspension of spores from this
culture in sterilized water. Foliage of a grapefruit tree in the
open was also sprayed with a part of this suspension.
Two weeks later canker infections began to appear on the
small tree in the greenhouse and later infection developed on the
foliage treated in the open. These infections developed into
typical Canker spots and pycnidia of the fungus was readily
found in these. Figures 7 and 8 in Bulletin 124 show the inten-
sity of the infection produced on the small tree. The fungus was
reisolated from these artificially produced cankers and in culture
exhibited the same growth characters as the culture from which
the inoculations were made. These results would not have been
given much weight at the time, for this was only a preliminary
test and I realized the chances for error, but a few days later I
received the work of Wolf and Massey of Alabama. Their re-
sults corroborated my own and since we were working with ap-
parently the same fungus I could reasonably interpret my results
as reliable. This accounts for the statement in the Annual Re-
port for 1914 concerning the cause of Canker.
Some of the other cultures referred to above, those from sin-
gle spore colonies and from young canker spots, were soon used
for infection purposes. These gave negative results. The ex-
periment was repeated with the same results. New isolations

Annual Report, 1915

were made and these cultures tried out. These results were nega-
tive. The fungus reisolated from the artificially infected leaves
failed to produce infection. Later in one case, a typical canker
spot resulted on Trifoliata stem from an inoculation with my-
celium from a single spore colony of the fungus in agar. This
plate culture was made with spores from a single pycnidum
taken from an active Canker spot.
The negative results obtained at first caused no unusual con-
cern, for most of these experiments were made in the greenhouse
and the failures were attributed to lack of proper conditions
necessary for infection to take place rather than any fault of
the cultures. In the paper read before the Citrus Seminar in
September, I called attention to the negative results obtained
and cited the positive experiments on which I had partly based
my conclusions. This paper was later published as a part of
Bulletin 124. After publishing the statement that the disease
was caused by the fungus in question, I exerted every effort to
demonstrate the fact by infection experiments, and through the
fall, winter and spring of last season, a great number of infec-
tion experiments were tried with pure cultures of the fungus
under every conceivable condition favorable to development of
the disease. In every case the results were negative and I began
to suspect that something was wrong.

A more detailed study was made of very young canker infec-
tions, and cultures made from the tissue of these usually gave
only bacteria. At first these were discarded, but finally it was
thought that these bacteria might play some part in the develop-
ment of the disease. To test this supposition, Citrus foliage was
treated as follows: Several trees were sprayed with a suspen-
sion of spores from pure cultures of the fungus. An equal num-
ber of trees were sprayed with a mixture of spores of this fungus
and bacteria isolated from Canker spots. A third lot was sprayed
with a suspension of bacteria. Check trees were sprayed with
sterile water. The bacteria were from pure cultures and were
isolated from the same source. The same was true of the fungus
cultures. These experiments were made in April, a few days
before the meeting of the State Horticultural Society. After the
meeting the trees thus treated were examined and the results
were quite conclusive. On the foliage that had been sprayed with
a suspension of bacteria, canker infections were beginning to


Florida Agriculturl Baperiment Station

develop. The foliage treated with the mixture of fungus spores
and bacteria also showed beginning canker infections. Nothing
had developed on the checks or the trees treated with fungus
spores only. Later observations on these same trees showed the
same results more pronounced. Recent infection experiments
with pure cultures of this bacterial organism have given positive
results in almost every case, and there seems to be no question
that Pseudomonas citri Hasse, is the cause of Citrus Canker.
The typical canker infections that I obtained from an appar-
ently pure culture of the fungus can best be explained on the sup-
position that the culture was not pure. Pa. citri was evidently
present with the fungus in the culture. I can easily see how this,
might have happened. Cornmeal agar was used almost exclu-
sively for isolating this fungus, for it grew rapidly and fruited
readily on this medium. On the other hand Ps. citri makes a slow
growth on this medium and usually several days elapse before
the colonies are visible to the naked eye. The culture referred
to was made from a single spore that was located and marked
just after it had germinated (about 24 hours after sowing) with
the low power compound microscope. The field around the spore
was carefully searched for foreign objects and none was found.
However, in this period a colony of Ps. citri would not have been
visible with the magnification used if it were present. In forty-
eight hours the colony had developed to about two millimeters in
diameter and would have completely obscured any bacterial
colony within the growth. In making sub-cultures from such a
colony it would be easy to carry over bacteria also, and that is
evidently what happened in this case. Unfortunately no sub-
cultures were made from this particular culture before it was
used in the infection experiment. It was discarded after use and
no verification of its contents could be made later.
The constancy with which this Phyllosticta has been asso-
ciated with Canker infections is not easily explained. It may be
a very common saprophytic form on Citrus, or some peculiar
property of Canker infections may be favorable to its develop-
ment. My infection experiments indicate that the fungus is not
parasitic to normal Citrus tissue. When spores and mycelium
(from cultures tested for purity) were inoculated into wounds
made in the bark of young Citrus twigs, only slight swellings
resulted and a very small patch of suberized tissue formed at the

Annual Report, 1915

point of inoculation. The fungus usually fruited in this tissue,
but no further development or spread of the spot took place. At
best these spots could only be considered suggestive of Canker
infections. Inoculations into Citrus leaves through punctures
failed to produce any material disturbance in the surrounding
tissue. When the fungus establishes itself in a Canker infection
it apparently continues to grow and may be a secondary agent
in the enlargement of such spots. No doubt a large majority of
the older Canker spots, found under natural conditions, are much
modified in appearance by invading fungi.
Citrus Canker has brought many critical situations in the
State and has excited more than ordinary interest in citrus grow-
ers. Last fall when the disease was recognized in its most seri-
ous light there was an immediate demand for full and definite
information concerning its nature and cause. This information
was indispensable to the eradication campaign that was finally
decided upon. It had to be supplied from the information at
hand at the time, and much of this information was prelimi-
Pseudomonas citri is now being studied to determine its cul-
tural reactions, relation to host plants and its ultimate effect on
the citrus tree. These investigations have not progressed far
enough to permit a report at this date.

During last season a preliminary study was made of a pecan
disease that is causing serious injury to pecan trees in certain
localities in the State. Specimens of this disease have been
received from time to time in past years, but more recently
many requests have come for information concerning the cause
and methods for controlling it.
The disease has apparently not been studied before and only
one reference to it or a similar disease was found in the liter-
ature available on pecan diseases. H. S. Fawcett in 1909 (Fla.
Ann. Rept. 1909, p. lxi.) under Pecan Diseases, refers to "Die-
back" and describes its symptoms. He suggests that it is proba-
bly caused by a species of Colletotrichum, since this fungus
was associated more or less constantly with diseased specimens.
The disease reported by Fawcett is undoubtedly the one we have
under study and in the future it will be referred to as Pecan Die-

Florida Agricultural Experiment Station

Pecan Dieback is a twig and limb disease that causes the
ultimate death of the parts attacked. It seems to attack trees
of any size and in time will cause the death of the entire tree.
In more advanced stages where large bearing trees are attacked,
a prominent feature of the disease is the large number of dead
limbs and branches that stand out in striking contrast to the
green foliage. Infections on young twigs and stems that are
more or less succulent are marked by dark brown areas. These
areas may be noted at the base of the petiole, and extend up-
ward and downward even along the stem of the twig. Toward
the base of a diseased twig, the bark is often watersoaked and
waxey in appearance. A definite margin marks the juncture of
the diseased and healthy tissue. The diseased portion of -
branches and limbs is usually sunken, dry and dark. There is a
distinct line of demarcation between the dead and living tissue.
The epidermis of such areas is commonly ruptured longitudin-
ally by stromatic masses of a fungus in which are embedded
from a few to many perithecia. Below the dead portion of larger
branches that have been killed by the disease, numerous new
twigs and shoots may appear, forming a cluster of growth sug-
gestive of "Witches Broom" or the rosette effect commonly
'observed in "Rosette." The characteristic leaf symptoms of
"Rosette" are lacking, however.
The disease has been studied in the field and laboratory in an
effort to determine the cause. The field work has been conducted
chiefly at Komoko, in a pecan orchard of 500 trees. All stages
of the disease were noted in this planting and many severe
cases were found where large bearing trees had been practically
killed by it.
An examination of diseased specimens usually shows a num-
ber of fungi present. A fungus has been repeatedly isolated
from diseased wood at the juncture of the dead and living tissue,
that is apparently the cause of the disease. This fungus has
been identified as Botryosphaeria berengeriana De Not., and
the perfect form is usually found abundantly on dead twigs and
branches that have been killed by the disease.
A number of inoculations have been made into healthy pecan
twigs with pure cultures of this fungus, and the characteristic
symptoms of the disease were produced in a majority of cases.

Annual Report, 1915

While sufficient work along this line has not yet been accom-
plished to draw definite conclusions, the results thus far obtained
suggest strongly that the fungus under study is the cause of
the disease.
The time and conditions under which infection takes place
normally have not been determined. Probably external agencies
play an important part in the spread and development of the
As a means of control it has been suggested to prune out
thoroughly all dead and diseased parts of the infected tree. In
addition, a thorough application of standard bordeaux mixture
or lime-sulphur solution is recommended as a dormant spray,
just before new growth appears in spring.
Experiments for control along these lines were made at
Komoko last season, but the work has not progressed far enough
to permit reporting at present.
Stem-End Rot. Phonopsis citri Fawcett. This disease was
not so severe during last season and it caused only appreciable
injury in a few localities early in the season. The comparatively
cool weather that prevailed during the greater part of the ship-
ping season was no doubt a factor in keeping this disease in
Citrus Scab. Cladosporium citri Penz. This disease is appar-
ently becoming more severe each year on the grapefruit. Many
reports have been received the last few months of severe attacks
of this disease on newly planted grapefruit trees. Formerly the
injury was more pronounced on bearing trees and the fruits
were usually more severely attacked -than the foliage. The last
two seasons fruit and foliage have suffered severely. One case
of scab was recently called to our attention on the new Lue Gim
Gong variety of orange. Fruit and leaves were infected. This
is of interest as the sweet orange is considered immune to scab.
Withertip. Colletotrichum gloeosporioides Penz. Consider-
able injury has been reported from attacks of this disease since
early spring. Young trees especially, that were injured by the
early frost of last November, have suffered severely.
Plant Pathologist.


Florida Agricultural Experiment Station

P. H. Rolfs, Director.
Sm: I submit the following report for the year ending June
30, 1915:
The work at this Station on diseases of vegetables commenced
August 4, 1914, and was interrupted during January 14 to May
1, 1915, which time was occupied with a special problem in con-
nection with Citrus Canker control.
The studies of vegetable diseases have been carried on accord-
ing to the general outline as far as practicable. An opportunity
for investigating certain, apparently new bacterial diseases
was looked for, but the bacterial diseases which came to
my observation during the year were all the well known
and studied ones, namely, the wilt of tomatoes, egg-
plants, and potatoes (Bacterium solanacearum Erw.Sm.),wilt of
cucumbers (Bacillus tracheiptcilus Erw. Sm.), black rot of cab-
bage (Bacterium campastris (Pammel) Erw. Sm.) and black
heart of lettuce (See Fla. Agrl. Exp. Sta. Ann. Rept., 1908, Ixxx-
lxxxvii, figs. 1 and 2, pl. V, and Fla. Agrl. Exp. Sta. Rept., 1912,
xcviii-c). Therefore, though some attention and time were
devoted to these diseases, no investigation work has been con-
ducted with them.
According to the development and importance of the diseases
during this year, my chief attention has been given to seed-bed
diseases of celery and tomatoes. Some other vegetable diseases
have been studied as much as opportunity offered.

It has been found, first, that these plants in seed-beds are
quite commonly affected by diseases caused both by plant patho-
gens, Rhizoctonia, for instance; and by animal parasites such as
Nematodes. Some of the plant pathogens attacking seedlings
are not restricted to, nor are more typical for, this stage of the
plant's life, but occur on mature plants also. Such is the case
with the rust of tomatoes (Phoma destructive Plowr.) and early
blight of celery (Cercospora Apii Fr.). These two diseases can
cause considerable injury to the plants in seed-beds but their
effect and control are principally the same as those in the field.
It is considered here that diseases of such nature should not be
classed, and have not been studied, as seed-bed diseases proper;
nor has any work been done by the writer on the Nematodes,


Annual Report, 1915

partly at least, for the same reason. The study has been re-
stricted to seed-bed diseases in a narrow sense of the word,
namely, to the diseases caused by plant pathogens and occurring
typically and primarily in seed-beds.
The above distinction of seed-bed diseases from field diseases
is not absolute, because there are some exceptions. Such excep-
tions are represented by celery and lettuce diseases, caused both
in the field and in the seed-bed by Sclerotinia libertiana Fckl.
In the seed-bed it produces a typical (in appearance) damping
off of both of these plants, while in the field it causes foot rot of
celery and drop of lettuce.

As far as the writer is aware, there is only one typical seed-
bed disease. This is the so-called damping off. The disease
varies in its manifestations considerably, according to the en-
vironment and the stage and nature of the plants themselves.
There are two forms of damping off. In one form the disease
kills the stem tissues at or above and below the level of the
ground. The injured part appears first as water-soaked, then
brownish, spots of various sizes. It can finally girdle the stem
and thus kill the plant, but as damping off affects only young
and succulent tissues the plants with considerable woody tissue
are often only partly injured, and may recover. Such is often the
case with tomato seedlings when they are not attacked very early
in their life.
In the other form of damping off, the plants are killed out-
right, and the general effect of the disease in such cases resem-
bles that of scalding with boiling water. This takes place espe" -
ally when the attacked plants are succulent, and in a dense
stand. It is often observed in celery and lettuce seed beds.
The importance of damping off can be well illustrated by the
experience of some, otherwise most successful truckers of Terra
Ceia Island. To have enough plants for two acres of celery,
they had to maintain a whole acre or more of seed beds, because
the beds were affected by damping off. This handicap alone was
sufficient to force them to abandon celery culture which other-
wise has been one of the most profitable lines of trucking in that
place. Of course, not everywhere in the State are conditions
nearly so bad, but they may be if control measures are not taken.
Field observations on the occurrence and mode of spread of
damping off indicated that the disease must have been due to

Florida Agricultural Experiment Station

a pathogen or pathogens. Hence, an extensive series of isola-
tions of the organisms associated with the disease was made.
The method of isolation used was that which has been in com-
mon practice for this kind of work. The affected parts of the
plant were first thoroughly rinsed in running water and then
disinfected for from ten to fifteen seconds in a one to one thou-
sand solution of corrosive sublimate in water. The desinfected
tissues were rinsed in several catches of sterile water, and
finally minute bits of the diseased tissues planted in petri dishes
containing a suitable medium such as hard potato agar. These
isolations from celery and tomato seedlings, in the majority of
cases, yielded pure cultures of the steril fungus, Rhizoctonia.
Whether this is the same one which is common on potato plants,
viz. vegetative stage of the Corticium vagum B. and C. var.
solani Burt, is not yet determined, although the .two organisms
are surely closely related.
Besides the Rhizoctonia the following other organisms isolated
should be mentioned here. From tomato seedlings, a Fusarium,
and from celery a Fusarium, Gleosporium falcatum (?), and
Sclerotinia libertiana Fckl. These fungi were associated with
damping off and, at least in the case of the Sclerotinia, are not
infrequently the actual cause of the disease. Whether the others
have anything to do with the disease, the writer cannot say.
A number of other fungi were sometimes isolated but their
association is so irregular that it seems reasonable to assume
that they are mere saprophites. Owing to the more or less con-
stant association of Rhizoctonia with damping off, it was con-
sidered essential to undertake the necessary inoculation work
first with this fungus. At the same time to ascertain the dis-
tribution of this organism and its relationship to seed-bed dis-
eases of other vegetables of economic importance in the State, a
number of isolations were made from damping off of cabbage,let-
tuce, cauliflower and eggplants. Itwas found that theRhizoctonia
here is also almost invariably associated with the disease and in
a great majority of cases the isolations from the diseased parts
of the plants yielded pure cultures of the organism directly. The
inoculation work conducted in our greenhouse proved beyond
reasonable doubt that this fungus is the cause or at least the
most common cause of the damping off of the plants mentioned.
Cotton, onions, China and garden beans, seedlings under green-
house conditions were also attacked by the Rhizoctonia and the
effect was identical with that of damping off.


Annual Report, 1915

The other organisms associated with the damping off have
not been tested with regard to their pathogenicity.
In other investigations of damping off in various parts of the
United States it has been commonly reported that another
fungus, Pythium de baryanum Hesse, was the principal patho-
gen. The writer has not isolated this fungus from damped off
plants in this State, but instead has almost invariably found
the Rhizoctonia.

Among various fungus diseases of vegetables which came
under my observation during this year, some diseases of various
plants appeared to be of especial prominence, and occupied a
considerable part of my time and attention. These are: lettuce
drop, early blight of celery, Phomopsis of eggplants, Cercospora
spots of peppers, cucumber "rust" and tomato "rust."
Lettuce drop was especially destructive and often, as in some
cases observed near Sanford and McIntosh, nearly destroyed the
entire crop. Field observations show that a continuous cropping
with lettuce and too close planting are in a considerable measure
responsible for severity of attack. Of course, weather condi-
tions are an important factor for the spread of the disease.
Sanitation, proper crop rotation and not too close planting are
recommended as preventive.
Among the diseases of celery, the .early blight, Cercospora
apii Fr., deserves mention. The disease occurred generally in
celery growing sections of the State, and had been observed
also on young plants in seed-beds. The spots on the leaves are
of a characteristic ash-gray color and spreading. The leaves
are eventually killed and the plants stunted.
The most serious fungus disease of eggplants was the
leaf spot and fruit rot caused by Phomopsis vexans (Sacc. and
Syd.) Hart. Some of the fields observed near Sanford were en-
tirely ruined by the disease.
Peppers were in many cases badly attacked by Cercospora
capsici Heald and Wolf. The characteristic black or brownish,
with grayish-white centered spots produced by this fungus occur
on all parts of the plant. Defoliation, girdling of the stems, and
rendering the fruits unmarketable are the prominent effects of
the disease.


Florida Agricultural Experiment Station

Cucumbers were most commonly attacked by the "rust"
(Peronoplasmopora Cubensis, (B. and C.,) Clint). The "rust"
leaf spots can easily be distinguished from other leaf spots of
cucumbers by a purplish powder of the spores on the lower
side of the leaves.
Tomato leaf and fruit spot and fruit rot commonly known
here as tomato "rust" and caused by Phoma destructive Plowr,
was found to be of a very general occurrence in Florida wherever
tomatoes are cultivated, and during any season of the year,
often causing considerable loss. Seedlings in the seed-beds are
sometimes badly affected by the disease. The "rust" was for
the first time observed by the writer during last August on
plants grown on the Experiment Station grounds. Later it was
found in many tomato fields in the central part of Florida and
on the West and East Coasts. The disease in its effect on the
fruit was fully described in a recent publication from the Bureau
of Plant Industry, U. S. Dept. Agr. (See Jamieson, Clara O.
Phoma destructive, the cause of a fruit rot of the tomato, Jour.
Agrl. Res. 4:1-20, pls. A. and B. and 1-6. 1915.)
The ordinary methods of control for the foregoing diseases
were recommended. Ammoniacal solution of copper carbonate
was suggested instead of bordeaux mixture for the later spray-
ings previous to marketing the vegetables, because the use of
the bordeaux at this time is objectionable on account of its pro-
nounced staining of fruits.
Assistant Plant Pathologist.


Annual Report, 1915

P. H. Rolfs, Director.
SIR: I submit herewith the report of the work in chemistry
for the fiscal year ending June 30, 1915.

Condition and Treatment.-The citrus grove has been fer-
tilized as usual this year. Two pounds per tree of the standard
formula were applied in the fall of 1914, and during the spring
and summer of 1915. The beggarweed, which has hitherto been
grown in the grove during the rainy season, failed to make a
good stand this summer, and cowpeas were sown instead.
An examination of the grove this spring indicated that the
trees were in better condition than at any previous time for
several years. A good thrifty growth was made on almost every
plot. The bloom was quite heavy. Practically every plot showed
some, and only four plots, numbers 4, 5, 34, 39 showed little or
none. A visit to the grove in June, however, disclosed the fact
that practically all this bloom had dropped without setting any
fruit. The indications are that the fruit will be very scattering,
with probably only a dozen or so on the best plots. The amount
of fruit matured in 1914 was so small that no samples were
taken for analysis.
An examination of the plots shows that the trees are not as
uniform in size as could be wished. However, in all but a few
plots at least five to eight trees can be picked out which are fairly
On a visit to the grove in June this year, gum pockets, in-
dicating the presence of dieback, were discovered on some trees.
This led to a careful examination of each tree for symptoms of
the disease. Dieback was found in twenty-nine plots on fifty-two
trees. On most of the trees the disease was in the gum pocket
stage, and was on the newest growth in nearly every case. The
gum pockets were not numerous on any of the trees. A careful
examination of the entire tree was usually necessary to find
them. It is interesting to note that, of the twenty-nine plots
showing dieback symptoms, sixteen had the disease on only one
tree. In every instance this tree was number five in the plot.
This fifth tree made up a total of twenty-eight trees out of the
fifty-two showing the disease. As we stated in the 1912 report,
'the grove, with the exception of the fifth tree of every plot,


Florida Agricultural Experiment Station

which was left as a check, was sprayed twice with bordeaux
mixture to control the dieback present in the grove at that time.
It would appear that the spraying was of considerable benefit
in controlling the disease and that the effects are lasting.
A considerable amount of frenching is present in nearly all
parts of the grove. The attack is severe on only five plots; plot
twenty-one is the most severely affected of any in the grove.
All but two trees in this plot show the typical frenched appear-
ance. Plots 11, 30, 28 and 39 are also badly frenched. The
severity is probably in the order named.
MEASUREMENT OF TBEE .-The trees have been measured as
usual this year. The diameter of each was taken six inches
above the bud. The average of the 480 trees in the grove for
1915 is 72.4 thirty-seconds of an inch. This is an increase of
16.5 per cent over 1914. The increase in 1914 over 1913 was
9.5 per cent.
In Table 83 is shown the increase in diameter of the different
plots from June 1909, to June 1915. The table also shows the
fertilizer treatment of each plot. Plot 4 has received no fer-
tilizer since the spring of 1914, because the excessive amounts
hitherto applied proved extremely injurious, killed several trees
outright and almost inhibited growth in the others. The table
shows that plot 2 has continued to make the largest growth.
Plot 1, second last year, has been replaced by plot 47, and now
occupies third place. The two floats plots, 36 and 35, have about
held their own. No marked changes in rank have occurred din-
ing the year.
The standing of plots 5, 6, 7 in the table shows which of tihe
three elements, nitrogen, phosphorus or potassium, when used
in excessive amounts, injures the tree most. Plots 5 and 7
receive a fertilizer in which the nitrogen is increased by one-
half over the standard, while plot 6 receives the standard
amount. Plots 5 and 7 rank 46th and 42d respectively, while
plot 6 ranks 21st. In general appearance there is a decided dif-
ference. The trees in plot 6 are much larger and have a more
thrifty appearance than those in the other two plots. It appears
that relatively large amounts of nitrogen, even when used with
other materials, will injure the trees more than like amounts
of the other two essential elements.

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