• TABLE OF CONTENTS
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 Title Page
 Frontispiece
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 Letter of transmittal
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Group Title: Annual report, University of Florida. Agricultural Experiment Station.
Title: Annual report for the fiscal year ending June 30th ...
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Permanent Link: http://ufdc.ufl.edu/UF00027385/00039
 Material Information
Title: Annual report for the fiscal year ending June 30th ...
Alternate Title: Florida Agricultural Experiment Stations annual report
Physical Description: 23 v. : ill. ; 23 cm.
Language: English
Creator: University of Florida -- Agricultural Experiment Station
Publisher: The Station
Place of Publication: Gainesville Fla
Publication Date: 1913
Frequency: annual
regular
 Subjects
Subject: Agriculture -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
 Notes
Statement of Responsibility: University of Florida, Gainesville, Florida, Agricultural Experiment Stations.
Dates or Sequential Designation: 1931-1967.
 Record Information
Bibliographic ID: UF00027385
Volume ID: VID00039
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AMF8114
oclc - 12029671
alephbibnum - 002452809
lccn - sf 91090332
 Related Items
Preceded by: Report for the fiscal year ending June 30th ...
Succeeded by: Annual research report of the Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida

Table of Contents
    Title Page
        Page i
    Frontispiece
        Page ii
    Table of Contents
        Page iii
        Page iv
        Page v
        Page vi
    Letter of transmittal
        Page vii
        Page viii
    Main
        Page ix
        Page x
        Page xi
        Page xii
        Page xiii
        Page xiv
        Page xv
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        Page cxxxii
    Index
        Index 1
        Index 2
        Index 3
        Index 4
        Index 5
        Index 6
        Index 7
        Index 8
        Index 9
        Index 10
        Index 11
        Index 12
Full Text



UNIVERSITY OF FLORIDA


AGRICULTURAL EXPERIMENT

STATION





2t6 REPORT FOR THE FISCAL YEAR
ENDING JUNE 30th,
1913






















THE E. 0. PAINTER PRINTING CO., DE LAND, FLA.
JUNE, 1914.













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CONTENTS

PAGE
LETTER OF TRANSMITTAL TO GOVERNOR OF FLORIDA -------------------- Vii
BOARD OF CONTROL----- ..------------------------------------ viii
EXPERIMENT STATION STAFF----------------------------------------- viii
LETTER OF TRANSMITTAL TO CHAIRMAN OF BOARD OF CONTROL ---------- iX
Investigation ----------------------------------------- ----- ix
Lines of Work ___--------------------------------------- x
Publications ------------------------------------------ xiv
REPORT OF AUDITOR-------------- --------------------------------- XV
REPORT OF ANIMAL INDUSTRIALIST .------------------------ ----
Dairy Herd -------------------------------------- ---- xvi
Milk Record ---.------------------------------------- ----- xvi
Beef Herd ------------------------- ---------------------- xvi
Hogs __--------------------------------------------------------- xvii
Japanese Cane, Fertilizer Test----------------------------------- xix
Japanese Cane, Cultivation Test-------------------------------- xxiii
Velvet Beans, Continuous Planting------------------------------ xxiv
Yields of Sweet Potatoes----------------------------- ----- xxv
Sweet Potato Silage-------------------------- ------------------ xxvi
Cassava Silage ----- -- --------------------------- xxvi
REPORT OF PLANT PHYSIOLOGIST ---------- ------------- xxvii
$Bordeaux Mixture for the Control of Dieback---------------- xxvii
Gumming of Citrus Trees produced by Chemicals-__-------- --xxx
Sand Cultures of Citrus Seedlings--------------------------- xliv
REiiro or ENTOMOLOGIST ------- ------- ----- ------- ----- liv
Further Spraying Experiments with Microcera-------------------- liv
Whitefly Conditions in Various Groves------------------------- lix
The Woolly Whitefly ----------------------------xi
Observations on Certain Citrus Insects-------------- --- Ixiv
Destructive Insects of the Year --------- ---------------- xv
REPORT OF PLANT PATHOLOGIST----------------- -----_ ---------- xxii
Melanose --------------------------- ------- -------------- xxii
Stem-End Rot ---------------------------------- --- lxxxv
Gummosis ------------------------------------ xxxv
Fruit Rots ------------------------------------------ xxxv
Scab --------------------------------------- xxxvi
REPORT OF ASSISTANT PLANT PATHOLOGIST ---__----- ---------- Ixxxvii
Lettuce Diseases --------------------------------------------- lxxxvii
Bacterial Rot of Cucumbers-----------------------------------xc
Tomato Diseases -------------------------------------- xciv
Beet Disease ---------------------------------------- ---- xcv
Celery Diseases ------------------------------------------------_ xcv
Onion Diseases ------------------------------------- ----xcv
Cantaloupe Diseases --------------------------- --------xcv
REPORT OF CHEMIST--------------- ----------------- xcvi
SCitrus Experimental Grove --------- -- ---------- -- xcvi
Soil Tank Experiment------- -------- ------------- xcviii
Composition of Citrus Fruit------------- -------------ciii.
REPORT OF ASSISTANT BOTANIST------- ----------------------- Civ
Selections of Useful Beans from the Cross of Florida Velvet by
Lycn ----------------------------------- --- -- civ
Precautions in .Breeding Work --------------- ----------------- cvi
Genera. Sources of Error __----------------------__ evii
Inheritance of Purple Color and Time of Flowering in Velvet Bean
Crosses ---------------------------------- cviii
Corn Crosses ------------------------------- cxxx









iv Contents
PAGE
BULLETIN III.-MELANOSE AND STEM-END ROT. PAGES I-16
Introduction ----------------------------- ------ 3
Melanose ------ ----------------------------------------------------- 4
Distribution of Melanose------------------------------------------- 4
Nature of Melanose------------------------------------------- 4
Appearance of Melanose------------------------------------------ 5
Effects of Melanose ---------------------------- 6
Relation to Growth Conditions ..-------- .------------------- 7
Comparison with other Diseases ----------------------------- 8
Cause of Melanose---------- ---- --------------------- 8
Culture Experiments _-------- --------------------- 9
Infection Experiments-------. -------------------------- 9
The Fungus and its Habits------- -------------------------- 12
Surface Injury from the Fungus--------- ------------------- 13
Stem-End Rot---------- ---------------------- 14
Description of Stem-End Rot------- ----------------------------- 14
Conditions favoring Stem-End Rot------------------------------- 15
Injury from the Fungus------------ ----------------------- 15
Control Measures ---------------------------------- --- 15
BULLETIN II2.-TOMATO INSECTS, ROOT-KNOT, AND "WIITE MOLD." PAGES I7-39
Boll-Worm, or Tomato Fruit-Worm- .--.--.--.----------------- ---. 21
Root-Knot -------------------------------------------------- 24
Thrips ..------ ---------_ --------------_ 26
Cutworms -------------- ------------------------ ------- 28
Horn Worms ---------.- -------------------.----- --------. 30
White Mold ------ -------------------------------------- 33
Aphis, or Plant-Louse------------ ------------------------------ 33
Flea-Beetles --------------------------------------------------- 35
Miscellaneous Insects ......-- ..-- ..-.-...---------- 36
Blister-Beetles ----- -------------------------- 36
White-lined Morning Sphinx------- -------------------------- 36
Army Worms ------ --------- .. ..------------------------- 36
Grasshoppers ------------------------------------- -- 37
Suckfly -------------------------------------------------- 37
Tomato Whitefly ---------- -------- ----------------38
Bugs ------------------------- --------------------------------- 38
BULLETIN II3.-PIG-FEEDING. PAGES 41-59
Summary --------------- ----------------------------------- 45
Composition of the Animal Body and Animal Products----- ------- 46
Composition of Feeds-------------------------------- ---- 46
How to Calculate Rations------------ --------------------------- 48
Some Good Rations---------- -------------- ------------------ 49
Pork Production --------------------------------------- 50
Pen-Feeding Unprofitable -------------------------------------- 51
Choosing a Breed ----------------------------- 51
Grading-up -------- ------------------------------------------------ 52
Location and Green Crops ----------------------------------------- 52
Care of the Herd-------------------------- ------------ 53
Experiment I ---------------------------------------- 54
Experiment II .--------------.-------------------- .----- 55
Experiment III -------------------------------------- 56
Experiment IV ---------------------------------------- 57
Experiment V --------------------------------------- ----- -----' 58
Experiment VI --------------------------------------- 59
BULLETIN II4.-MIhK PRODUCTION II. PAGES 61-76
Introduction -------------------------------------- 63
Market Demand ----------------------------------------------- 63
Most Profitable Directions of Dairy Work--- ------------------ ----- 64









Contents


Factors Influencing Cost of Production ---------------
Experiment I _--------------- ____________________--
Experiment II ---------------....._--_--__ ------ _
Milking Records -------------....__ ____----------
Comparative Returns from Milk, Cream and Butter------ -----------
Returns from Individual Cows------------------------------


PRESS BULLETINS


193.-The Southern Grass Worm.
Fall or Army Worm.
Methods of Control.
Description and Life-History.
194.-The Cotton Caterpillar.
Remedy.
Life-History.
195.-Stem-End Rot and Scale Insects.
Spraying for Scale Insects.
Pruning Out Dead Wood.
196.-Hybrid Corn.
Tests.
The Cross.
Hybrid Seed-Corn.
197.-Crossing Corn.
Object of Crossing.
Method of Crossing.
First Year.
Second Year.
198.-Protecting Corn from Weevils.
Better Cribs Needed.
How to Fumigate.
199.-Melanose and Stem-End Rot.
Preventive Measures.
Cause.
Habits of the Fungus.
2oo.-Lettuce Rot.
Control.
Seed-Beds.
Cause.
201.-Feed Cost of Milk per gallon.
Cost of Feed.
Cost of Milk.
Comparison of Cows.
202.-Saving Japanese Cane for Win-
ter Feed.
Standing Cane.
Storing Under Cover.
Windrowing.
Shocking.
203.-Bulletins and Reports on Hand.
204.-Crossing Legumes.
The Cross.
The First Generation.
The Second Generation.
Selecting for Constancy.
205.-Red Spiders.
Remedy.


Sulphur and Lime.
Sulphur Spray.
Sulphur Compounds.
The Red Spiders.
206.-Melon Aphis.
Spraying.
Fumigation.
Dusting.
Clean Culture.
Natural Enemies.
207.-Tomato Rust.
Symptoms.
Preventive measures.
Cause.
208.-Natal Grass.
Soil.
Seed-Bed.
Seeding.
Hay.
209.-Melon Worm and Pickle Worm.
Remedies.
Description and Life-History.
2Io.-Bulletins and Reports on Hand.
21I.-Instruments for Cultivation.
Weeder.
Surface Cultivation.
Riding Cultivators.
Spring-Tooth Cultivator.
Mulch Harrow.
Cultivator.
Disk Cultivator for Sweet Po-
tatoes.
212.-The Woolly Whitefly.
Appearance.
Eradication and Control.
Parasitic Fungi.
213.-Winter Layers.
Winter-Hatched Pullets.
Spring-hatched Pullets.
Feeding.
The Second Summer.
Old Hens Not Productive.
Determining Ages.
214.-Mealy Bug.
Control.
Life-History.
Enemies.


INDEX TO REPORT, BULLETINS, AND PRESS BULLETINS


PAGE
64
65
68
71
73
74



















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Hon. Park Trammell,
Governor of Florida,
Tallahassee, Fla.
SIR: I have the honor to transmit herewith the annual report
of the Director of the Florida Experiment Station, for the fiscal
year ending June 30, 1913.
Respectfully,
P. K. YONGE.
Chairman of the Board of Control.
















BOARD OF CONTROL
P. K. YONGE, Chairman, Pensacola, Fla.
T. B. KING, Arcadia, Fla.
E. L. WARTMANN, Citra, Fla.
F. P. FLEMING, JR., Jacksonville, Fla.
W. D. FINLAYSON, Old Town, Fla.

STATION STAFF
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.
S. E. COLLISON, M.S., Chemist.
JOHN BELLING, B.Sc., Assistant Botanist, and Editor.
O. F. BURGER, M.S., Assistant Plant Pathologist.
S. S. WALKER, M.S., Assistant Chemist.
J. H. CARPENTER, B.S., Assistant Chemist*.
JOHN SCHNABEL, Assistant Horticulturist.
U. C. LOFTIN, B.S., Laboratory Assistant in Entomology.
F. M. O'BYRNE, A.B., Laboratory Assistant in Plant Physi-
ology.
M. S. PYLE, Librarian.
E. G. SHAW, Secretary.
K. H. GRAHAM, Auditor and Bookkeeper.
M. CREWS, Farm Foreman.
*Temporarily employed for citrus analytical work.












Report For Fiscal Year Ending

June 30th, 1913


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, 1913, and I respectfully request
that you transmit the same, in accordance with the law, to the
Governor of the State of Florida.
Respectfully,
P. H. ROLFS,
Director.
INVESTIGATION
The investigational work carried on by the Experiment Sta-
tion has continued along the lines laid down in previous years.
Several problems that have been under study for several years
have been completed, new ones being taken up to supplement those
not completed.
The problems that were originally taken up were such as ap-
peared, in the judgment of those in the best position to judge, to
be of greatest importance for the development of the agriculture
and horticulture of the State. With the rapid advance in both of
these lines in the State, new problems are constantly arising, so
that the demand for investigation has far exceeded our ability to
carry on the work. The new lines of agriculture which are con-
stantly being developed and the new adjustments which are being
made, require from time to time a readjustment of the problems
we have taken up.
Special problems are constantly arising in connection with the
recently drained land. For the most part the work carried on in
this region is not only new to the State, but also new to the people
who are carrying on tie work. It appears that up to the present
no detailed or careful investigations have been made on drained
muck lands in sub-tropical regions. The differences in rainfall
and temperature make it impracticable to adopt and transplant








Florida Agricultural Experiment Station


information gained in similar drained regions in more northern
latitudes.
LINES OF WORK
PLANT INTRODUCTION-The plants and seeds that have been
introduced from tropical countries and elsewhere number now
over twelve hundred, attention having been particularly centered
on forage crops. Thirty-two varieties of alfalfa have been tried
out, and records relating to them kept for a number of years.
Fifty-one different numbers of velvet beans (Stizolobium) have
been tried out in. the last eight years. A large percentage of
these have proven themselves of no value under Florida condi-
tions. Some of the varieties require so long a time for coming to
maturity that they are useless.
The Chinese velvet bean (Stizolobium niveum) was introduced
four years ago. It was distributed to about forty different sta-
tions in the State to be tried out under varying conditions. The
habits of this velvet bean are similar to those of the Lyon and
Florida, but it differs from either of these in that the pods ripen
about a month earlier. The pods have the bad habit of springing
open and scattering the seeds in the field. To avoid this, the pods
have to be gathered early in the season.
A general view of the plant introduction grounds is given in
Fig. I. In the foreground are shown Canavalias, and beyond are
Japanese canes introduced from Asiatic countries.
Among recent introductions that appear to be worthy of a
place in the flora of Florida is the Elephant Grass (Saccharum
ciliare). This was received from Professor C.. V. Piper, of the
Bureau of Plant Industry on June 29, 1910. It makes a very
vigorous and robust growing plant, apparently well worthy of
cultivating for ornamental purposes (See Fig. 2). The question
as to its usefulness as a forage plant has still to be determined.
Apparently the leaves are too coarse and woody to be of much
value in this direction. However, as it belongs to the same genus
as sugar-cane and Japanese cane, it might prove to be of con-
siderable value. It is quite resistant to cold, and produces a large
amount of green matter in the course of a year. Should it prove
useful as a forage plant, it would add greatly to the possibilities
of producing forage that can be used by stock in winter time
without having been harvested.
DAIRY PROJECT.-The work by the animal industrialist has
been mainly directed toward building up a dairy herd and testing







Annual Report, 1913


the various Florida feeds and methods of feeding for the produc-
tion of milk in the most economical way. Carefully compiled
data have been secured from our dairy herd as to the amount of
milk produced under varying feed conditions. Many of the data
secured have been printed in Bulletin 114.
PIG-FEEDING PROJECT-The rapid development of pork pro-
duction in Florida has made this one of the most important lines
of investigation that can be taken up. Extensive work on this has
been recorded in Bulletin 113. A large quantity of additional
data has been collected. The attention of the animal industrialist
has been directed especially to the feeding of Florida-grown
forage and Florida-grown feeds to hogs, using the well-known
standard feeds for these animals as checks.
AGRONOMY PROJECT-Extensive work has been conducted in
the testing of the action of fertilizers on the yield of feed and the
sugar content of Japanese cane. Japanese cane is intended primarily
for forage purposes. Various tests have been made as to its value
for feeding dairy animals, and also for feeding pigs of different
stages of growth. Some interesting results have been brought out
by the continuous fertilizing of Japanese cane by different kinds of
fertilizer.
Continuous plantings of velvet beans have been carried on
during the last six years, and careful record has been kept of the
yield of seed every year. The general opinion that velvet beans
do not produce as large a crop when planted continuously on the
same soil seems to be borne out by these tests.
PROJECT I.-The Soils and Fertilizers Project includes the
determination of the effect of quantity and kind of fertilizer ap-
plied to citrus trees on the composition of leaf. wood and fruit;
the study of abnormal changes of leaf, wood, and fruit induced
by varying the fertilizer; the changes produced by these chemicals
in the soil to which they have been applied; and the loss of plant
food by leaching or otherwise.
Attention this year has been chiefly directed to: (I) A study of
the trees of the experimental citrus grove which was established
five years ago, as to the effects of the different treatments on
them.
(2) The study of the losses of fertilizers due to leaching
from the soil has been continued. This has given important new
information.
(3) An extensive study was made of the composition 'of







Florida Agricultural Experiment Station


citrus fruit at different periods during this year. Determinations
were made of the percentages of acid and sugar contained in the
fruit during the period of ripening. The analyses were begun on
October I, 1912, and continued until May I, 1913. During this
time nearly six hundred analyses of fruit were made.
This work was made possible by the donation of $600 from
the Florida Citrus Exchange for. this particular line of investiga-
tion, and I wish to thank this organization for its generous help.
PROJECT II.-This project includes the study of various phases
of citrus disease, pineapple diseases, and vegetable diseases. In
the citrus field most of the work of the year was directed to the
study of melanose and stem-end rot. The plant pathologist was
able to prove the connection between the Phomopsis citri (which
had been previously established by the Experiment Station as the
cause of stem-end rot) and the fungus that causes melanose. A
definite plan for combating this trouble in the citrus grove is being
undertaken. The minor line of study taken up by the pathologist
includes gumming, buck-skinning and silver-scurfing.
The associate plant pathologist gave all of his time to the
study of vegetable diseases, directing his chief attention to the
bacterial disease which causes leaf spotting and rotting of cu-
cumber fruit.
PROJECT III.-The Citrus Whitefly Problem. The entomol-
ogist of the Experiment Station has given his major time to the
study of the life history and distribution of Aleurodes howardi,
the woolly whitefly. A careful study is being made of the effect
of different spraying materials upon this pest. Its parasites are
also being given careful attention. The minors under this project
which receive attention are the whiteflies which belong to the
species Aleurodes citri and Aleurodes nubifera, scale insects, and
the velvet-bean caterpillar, Anticarsia gemmatilis.
PROJECT IV.-This project includes nutrition and malnutri-
tion studies, especially with regard to citrus trees. Particular
attention is directed to ascertaining the effects of certain chemicals
largely used as fertilizers in Florida, especially as to their bearing
on the mal-nutritional disease known as die-back. A large amount
of progress has been made in the technical study of this disorder.
Extensive field investigations have been made during the year.
There have been also added greenhouse studies with plants under
exact control. These exact studies in the end will lead to a prac-
tical solution of the difficulty. Die-back has been known for over







Annual Report, 1913 xiii

twenty-five years as a disease of citrus trees, and a great deal of
difficulty has been experienced in controlling it.
PROJECT V.-Plant-Breeding Project. The chief work in this
project has been directed toward the selection of the segregates
resulting from crossing the Florida velvet bean with other velvet
beans (Stizolobium). The object of the work being to-study the
manner of inheritance and to select and breed to constancy use-
ful segregates from the different crosses. Several segregates se-
lected from these crosses are showing possibilities of becoming
more useful than the straight line velvet beans that are now being
grown. The minor problem in this project is that of corn hybrid-
izing. This minor problem is given attention whenever it becomes
practicable to do so without interference with the major.
CO-OPERATIVE WORK.-The Director of the Experiment Sta-
tion has co-operated to the fullest extent with the Bureau of Plant
Industry in the introduction and dissemination of useful agricul-
tural and horticultural plants. The principal lines of work have
been conducted in co-operation with Prof. C. V. Piper of the
Bureau of Plant Industry. Large numbers of the seeds obtained
for planting in the Introduction Garden have been received di-
rectly from this source. The generous co-operation of Prof.
Piper has made it possible to get some valuable results.
The plant pathologist has also co-operated with the Bureau
of Plant Industry in studying citrus-disease problems in connec-
tion with the shipping of citrus fruits. This work can be carried
on mutually to great advantage, since the officers of the Experi-
ment Station are fully acquainted with local conditions in the
State, but would be unable to conduct special experiments that
would require a great deal of attention to the materials when they
arrived in distant markets.
CHANGES IN THE STAFF.-Changes in the staff during the
present fiscal year have been unimportant. In September, 1912,
Miss Eleanor G. Shaw accepted the position of Secretary to the
Experiment Station. On September 23, 1912, J H. Carpenter,
(B.S., Cornell) accepted the position of temporary Chemist to
carry on the work of analyzing citrus fruits for acid and
sugar content. He continued his work until April I, 1913. On Jan-
uary 23, 1913, Mrs. M. S. Pyle accepted the position of Libra-
rian, and resigned May 5, 1913. On June I, 1913, U. C. Loftin,
Laboratory Assistant in Entomology, resigned to accept a posi-
tion with the Bureau of Entomology, U. S. Department of Agri-








Florida Agricultural Experiment Station


culture. On July I, 1913, F. M. O'Byrne, Laboratory Assistant
in Plant Physiology resigned his position to take up work with
the E. O. Painter Fertilizer Company.

PUBLICATIONS

The following press bulletins and bulletins, with the annual re-
port, were published during the year:

PRESS BULLETINS
No. Title. Date and Author.
192 Bulletins and Reports on hand. ... July 6, 1912.
193 The Southern Grass Worm, or
Fall Army Worm.............. uly 6, 1912-J. R. Watson.
194 The Cotton Caterpillar .......... July 27, I912-J. R. Watson.
195 Stem-End Rot and Scale Insects.. August 3, 1912-H. E. Stevens.
196 Hybrid Corn .................... August 24, 1912-John Belling.
197 Crossing Corn .................. September 14, 1912-John Belling.
198 Protecting Corn from Weevils... September 21, 1912-C. K. McQuarrie.
199 Melanose and Stem-End Rot..... October 5, 1912-H. E. Stevens.
2oo Lettuce Rot .................... October 19, 1912-0. F. Burger.
201 Feed Cost of Milk per Gallon.... October 26, 1912-J. M. Scott.
202 Saving Japanese Cane for Winter
Feed ....................... November 9, 1912-C. K. McQuarrie.
203 Bulletins and Reports on Hand... January II, 1.912.
204 Crossing Legumes ............... January 18, 1912-John Belling.
205 Red Spiders .................... February I, 1913-J. R. Watson.
206 Melon Aphis .................... March 29, 1913-J. R. Watson.
207 Tomato Rust .................... April 5, 1913-0. F. Burger.
208 Natal Grass .................... April 19, 1913-J. M. Scott.
209 Melon Worm and Pickle Worm.. May 3, I913-J. R. Watson.
210 Bulletins and Reports on Hand.. May 3, 1913.
21.1 Instruments for Cultivation...... May o1, 1913-A. P. Spencer.
212 The Cuban or Woolly Whitefly... May 31, 1013-J. R. Watson.
213 Winter Layers .................. June 14, 1913-A. P. Spencer.
214 Mealy Bug ...................... June 21, I913-J. R. Watson.
BULLETINS

III Melanose and Stem-End Rot; 16
pages ....................... December, 1912-B. F. Floyd and H. E.
Stevens.
I12 Tomato Insects, Root-Knot and
"White Mold"; 23 pages...... December, 1912-J. R. Watson.
113 Pig-Feeding; 19 pages........... February, 1913-J. M. Scott.
114 Milk Production II; 16 pages.... June, I913-J. M. Scott.
ANNUAL REPORT FOR 1912: 129 pages, with index to all publications of
Sthe year.








Annual Report, Ipr3


REPORT OF AUDITOR

P. H. Rolfs, Director, Florida Agricultural Experiment Station,

SIR: I respectfully submit the following report of the credits
received'and expenditures vouchered out of funds as specified.

RECEIPTS
Sales and
Hatch. Adams. Donations.
By balance on hand, July I, 1912........ $913.86
By appropriation from U. S. Treasury.. $15,ooo.oo $15,000.00
By donation, Citrus Excharge ...... ..... ........ ........ 600.oo
By receipts, Sales Fund ................ ........ ........ 916.69

Total ..............................$15,ooo.oo $15,ooo.oo $2,430.55

EXPENDITURES
To salaries ............................. $6,463.34 $11,707.20 $1,251.67
Labor .................................. 2,967.46 945.98 311.69
Publications .................... ........ 1,540.46 .... 464.Io
Postage and Stationery ................. 636.35 69.96 74.29
Freight and Express ................... 160.98 139.01 26.23
Heat, Light and Power ................. 261.93 16.60 3.30
Chemical and Laboratory Supplies....... 2.00 521.18 31.52
Seeds, Plants and Sundry Supplies...... 282.62 382.75 26.07
Fertilizer ... ... ..... .... 194.45 7.63
Feeding Stuffs. ........ ............. 1,099. ........ 20.85
Library ............. ............... 309.33 54.87 62.43
Tools, Machinery and Appliances ........ 296.33 111.49 9.25
Furniture and Fixtures ................. 8541 ............
Scientific Apparatus and Specimens ..... 11.55 293.71
Traveling Expenses .................... 143-46 59%5 13.05
Contingent ............................. 21.oo .
Buildings and Land .................... 524.34 149-97 11.90
Balance unexpended ............... ....... ..... 24.20

Totals ............................ $15,000.00 $15,000.00 $2,430.55

Respectfully submitted,
K. H. GRAHAM,
Auditor.








xvi Florida Agricultural Experiment Station

REPORT OF ANIMAL INDUSTRIALIST

P. H. Rolfs, Director,

SIR:
I submit the following report of the Department of Animal In-
dustry for the year ending June 30, 1913.

DAIRY HERD

The dairy herd remains the same as given in the last Report,
with the exception of the increase in calves. All of the calves
dropped during the year have not been retained-; all bull calves have
been sold as veal, and only heifer calves retained.

MILK RECORD

Table I shows the milk record of the cows for the year from
July I, 1912, to June 30, 1913.

BEEF HERD.

The four Shorthorn cows that were purchased in the-spring
of 1907 make up the breeding herd. These cows, however, are
now getting well along in years, and it would be well to dispose
of them and invest the money in younger animals.

TABLE I
AMOUNTS OF MILK PRODUCED FROM JULY I, 1912, TO JUNE 30, 1913
Cow Milk Produced, Days in
No. Pounds. Milk.
S ... ................................................ 3651.3 293
2 ................................................... 3595.0 365
4 ............. .................................. 2725.1 365
5 ............ ........... ..... ..... ..... 2583.8 293
6 ............................................ 2775.2 299
7 ............. ... ..... .................... ...... 3334.2 272
8 ..................... ........................ 2916.5 301
9 .................................................. 3433-1 365
1O ..................................................... 3411.6 365
S.......................... ......... ................ 3187.9 337
13 ................................................. 1353.2 226
14 .- ......... ........... ............................ 1943-1 315
15 ........ ......................................... 895.7 153
16 .................................................. 2543.9 268

One Shorthorn bull was sold during the year to Mr. Joseph
Cameron of Sanford, Florida.








Annual Report, 1913 xvii

HOGS
During the year two feeding experiments have been conducted.
The first test was conducted with eight pigs divided into two equal
lots. Lot I was fed corn and green cowpeas. Lot II received
corn and green sorghum. In all cases equal amounts by weight
were fed, so that for each pound of corn a pound of green feed
was given.

TABLE II
PIG-FEEDING EXPERIMENT I
LOT I-FOUR PIGS
Feed Consumed- Pounds.
Shelled corn ................................................... 466
Green cowpeas ........................... .. ...... ...... . 466

Weights and Gains
Weight at beginning'of experiment, September 3, 1912................ 293.3
Weight at close of experiment, October 17, 1912....................... 373.0
Gain in forty-six days ............................................ 79.7
Average gain per head ................... ....... ............... 19.9
Average daily gain per head ...................................... 0.43
Average daily gain per I,oo0 pounds live weight ...................... 5.9
Cost per pound of gain ..................................... ..$ 0.122

LOT II-FouR PIoG
Feed Consumed- Pounds.
Shelled corn ........................................................ 466
Green sorghum .......................... ... ..................... .. 466

Weights and Gains.
Weight at the beginning of experiment, September 3, 1912 ........... 296.6
Weight at close of experiment, October 17, 1912 ....................... 363.0
Gain in forty-six days .............................. ......... ..... 66.4
Average gain per head .............................................. 16.6
Average daily gain per head ....................................... 0.36
Average daily gain per I,ooo pounds live weight ...................... 4.9
Cost per pound of gain .......................................$ 0.147

In this feeding test, corn was figured as $1.90 per hundred,
the market price at the time the test was conducted; and green
cowpeas and sorghum, at 20 cents per hundred.
It only requires a glance at table II to show that corn and
green cowpeas were more effective as a pork producer than was
corn and green sorghum. The corn and green cowpeas not only
produced a larger daily gain per head, but they produced pork at
2.5 cents per pound less cost. A difference of 2.5 cents per pound
in the cost of production means a considerable difference in the
profits to be obtained in the marketing of the hogs from the farm
during the year.










xviii Florida Agricultural Experiment Station

The second test was conducted with three lots of pigs. The
pigs in Lot I were fed shelled corn and green rape only. The
pigs in Lot II were fed three parts of shelled corn, and one part
by weight of peanuts, with green rape. The pigs of Lot III were
fed equal parts by weight of shelled corn and peanuts, with green
rape.
This feeding test was begun on January 31, 1913, and closed
March 14, 1913, lasting forty-three days.

TABLE III

PIG-FEEDING EXPERIMENTS II
LOT I
Feed Consumed- Pounds.
Shelled corn .................. ... ........ ................... 55. 551
Rape ................................ ............................ 03
Weights and Gains

Weight at beginning of experiment, January 31, 1913.............. ..... 335
Weight at close of experiment, March 14, 1913 ...................... 453
Gain in forty-three days ............................ ............. 118
Average gain per head ............................................. 29-5
Average daily gain per head .................. ..................... 0.686
Average daily gain per i,ooo pounds live weight ..................8.. 8.2
Cost per pound of gain ................ ............. ..... $ 0.139
Pounds of feed to make one pound of gain........................... 4.67

LOT II.
Feed Consumed- Pounds.
Shelled corn ............................. ...................... 516
P eanuts ............................................ ............... 172
Rape .................. ........................... ................ 29
Weights and Gains.

Weight at the beginning of experiment ............................. 469
W eight at close of experiment ....................................... 624
Gain in forty-three days ...................... ............... ..... 155
Average gain per head ...................... ... . .............. 31
Average daily gain per head ........................................ 0.72
Average daily gain per I,ooo pounds live weight ...................... 7.7
Cost per pound of gain ......................... ...... ..... $ 0.146
Pounds of feed to make one pound of gain............................ 4.44

LOT III.
Feed Consumed- Pounds.
Shelled corn .................................................... .. 344
Peanuts ................................. . .... ... ..............* 344
Rape ......... ............. .............. .......................... 29
Weights and Gains.

Weight at the beginning of experiment .............................. 469
Weight at close of experiment ........... ....................... 635
Gain in forty-three days .......................... ................ 166







Annual Report, 1913


Average gain per head ............................................. 33.3
Average daily gain per head.................................... .... 0.774
Average daily gain per I,ooo pounds live weight ...................... 8.25
Cost per pound of gain ................................... ...... $ 0.156
Pounds of feed to make one pound of gain .......................... 4.14
The results of this test (Table III) bring out two points very
clearly.
(1) As the amount of peanuts in the rations was increased
there was a noticeable increase in the average daily gains. When
one part peanuts and three parts corn by weight were fed, the
average daily gain was 0.72 pounds. When peanuts and corn
were fed in equal amounts by weight, the average daily gain was
0.77 pounds.
(2) As the amount of peanuts in the ration was increased,
there was a noticeable increase in the cost of producing a pound
of gain. When corn and rape only were fed, the cost of pro-
ducing a pound of gain was 13.9 cents. When one part peanuts
and three parts corn were fed, the cost per pound of gain was 14.6
cents. When peanuts and corn were fed in equal parts by weight,
the cost per pound of gain was 15.6 cents.
The feeds in this test were given the following valuation:
corn, $1.50 per hundred; peanuts, $1.50 per hundred; and rape,
20 cents per hundred.
Peanuts are a good fat producer, but their high cost makes
their use as a hog feed prohibitive. The results of this test would
indicate that for pork production peanuts are only worth about
thirty or forty cents per bushel.
The hogs fed peanuts presented a better appearance than did
those fed on corn and rape only. They were more thrifty looking.

JAPANESE CANE FERTILIZER TEST
The Japanese cane fertilizer experiment, begun in the spring
of 1909, has now been under observation for four years. Even
with the results of four crops, it is rather difficult to draw defi-
nite conclusions as to which is the best fertilizer or combination
of fertilizers to use. (See Table IV).
The average yield of green forage per acre for the eight plots,
for the year 1909 (the first year of the experiment), was 19.88
tons. The average yield per acre for the second year was 13.75
tons, or a decrease of 6.13 tons per acre, nearly 31 per cent. The
average yield per acre for the third year was 12.11 tons, a decrease
over that of the second year of 1.64 tons. The percentage decrease








xx Florida Agricultural Experiment Station

between the second and third year is much less than that between
the first and second year. The average yield per acre for the fourth
year was only 7.76 tons. The decrease in yield between the third
and fourth years was 4.35 tons per acre, a decrease of 35.9 per cent.

TABLE IV
JAPANESE CANE FERTILIZER TEST. 1909-1912

Plot Plot Plot Plot Plot Plot Plot Plot
I II III IV V VI VII VIII
Dried blood, Ibs. -_------ 112 ----. 112 ---- 112 -- 112 112
Sulphate ammonia ---.--- --------_____ 72 -- 72 ..
Muriate potash ---------- 84 84 84 84 -
Sulphate potash ----------- ----- --_-- ---_--- -----84 84 84
Acid phosphate ----_---------- 224 224 224 224 224 224 224
Ground limestone --------- ----- ---------------------- __- 2000
Total ---------------196 308 336 380 420 380 42 420

Yield, tons, 1909 ----------- 24.2 17.7 16.1 19.1 19.54 18.9 16.6 27.03
Yield, tons, 1910 ----------- 14.6 12.4 10.0 14.4 11.8 16.7 14.1 16.00
Yield, tons, 1911 ----------- 7.08 9.0 9.63 14.36 13.56 15.48 14.02 14.10
Yield, tons, 1912 ----------- 6.38 6.84 3.68 7.92 7.26 9.62 10.68 10.28
Average ----------- 13.06 11.50 9.87 13.95 13.04 15.18 13.86 16.85

Sucrose p. c., 1909 ---------- 11.85 13.50 13.75 13.65 13.60 13.50 13.58 13.78
Sucrose p. c., 1910 - 11.00 10.85 10.50 11.00 1120 11.10 10.95 10.90
Sucrose p. c., 1911 --------- 9.30 9.24 6.12 9.00 7.92 6.90 8.12 9.18
Sucrose p. c., 1912 --- 11.25 11.12 11.17 12.14 11.48 11.65 11.37 11.87
Average --------------10.85 11.17 10.38 11.44 11.02 10.78 11.00 11.59

Brix 1909 ---------------- 16.70 17.20 17.70 17.40 17.40 17.5 17.60 17.80
Brix 1910 ---------------- 15.35 15.40 15.30 15.40 15.60 15.60 15. 15 15.50
Brix 1911 ------------------ 14.00 13.90 13.60 13.50 1400 14.20 14.30 14.20
Brix 1912 ------------------ 15.40 15.48 16.05 16.28 15.63 15.70 15.60 16.00
Average -------------- 15.36 15.49 15.91 15. 15.65 15.75 15.75 15.87


Apparently this annual decrease in yield is due to not enough
fertilizer having been applied each year to supply the demands
of the crop.

EFFECT OF DIFFERENT SOURCES OF AMMONIA

In comparing the average yield for four years from plots IV
and V, we see that plot IV, fertilized with sulphate of ammonia,
muriate of potash and acid phosphate, gave an average yield of
13.95 tons of green matter. Plot V, which was fertilized the
same as plot IV except that the source of ammonia was dried
blood, gave an average yield per acre of 13.04 tons of green mat-








Annual Report, 1913


ter, a difference of 0.9 tons. When the same sources of ammonia
are compared in combination with sulphate of potash instead of
muriate of potash, there was an increased yield in favor of sul-
phate of ammonia of 1.23 tons. Whether this increase is due
to the use of sulphate of ammonia, or to the sulphate of potash,
it is difficult to say.
Fertilizing had no effect on the percentage of sucrose in the
Japanese cane.
EFFECT OF GROUND LIMESTONE
Ground limestone was not applied every year, but every other
year. It was applied at the rate of one ton per acre.
The first year it produced an increased yield of 10.97 tons per
acre of green material. The second year there was an increased
yield of only 1.9 tons per acre of green material. Ground lime-
stone was again applied at the beginning of the growing season of
the third year. The second application of ground limestone seemed
to have no effect on the yield. The yield of cane the year follow-
ing the second application of ground limestone was about the same
as that of the check plot. Therefore, about the only conclusion
that can be drawn from this work is that ground limestone had
no effect on yield of green material after the first application.
Limestone had no effect on the sucrose content of the Japanese
cane.
EFFECT OF DIFFERENT SOURCES OF POTASH
We may compare the yields of plots IV and VI. Plot IV was
fertilized with sulphate of ammonia 72 pounds, muriate of potash 84
pounds, and acid phosphate 224 pounds per acre. Plot VI was
fertilized the same, except that 84 pounds of sulphate of potash
was used instead of muriate of potash. The yields the first year
(19o9) were: plot IV, 19.1 tons; plot VI, 18.9 tons; with a dif-
ference of 0.2 ton in favor of muriate of potash. The yields the
second year (1910), were: plot IV, 14.4 tons; plot VI 16.7 tons:
with a difference of 2.3 tons in favor of sulphate of potash. The
yields the third year (1911), were: plot IV, 14.36 tons; plot
VI, 15.48 tons; with a difference of 1.12 tons in favor of sulphate
of potash. The yields the fourth year were; plot IV, 7.92 tons;
plot VI, 9.62 tons; with a difference of I.7 tons in favor of sul-
phate of potash. The average yield for four years with muriate
of potash was 13.95 tons; and the average of four years when
sulphate of potash was used was 15.18 tons, giving a difference
of I.23,tons in favor of sulphate of potash..








xxii Florida Agricultural Experiment Station

Plots V and VII also give a comparison of sulphate and muri-
ate of potash. Plot V was fertilized with dried blood 112 pounds,
muriate of potash 84 pounds, and acid phosphate 224 pounds per
acre. In plot VII, 84 pounds of sulphate of potash were used
instead of muriate of potash. One difference 'that should be
noticed is that in plots V and VII the source of ammonia was
dried blood. (However the same amount of actual ammonia was
applied to all plots.) For the average of four years there was
an increase in yield of 0.82 tons per acre in favor of sulphate of
potash.
It will be seen by examining Table IV-that in all cases muri-
ate of potash when applied in a complete fertilizer produced a
heavier yield the first year, but after the first year the sulphate of
potash in all cases gave the best yield.

SUMMARY OF JAPANESE CANE FERTILIZER TEST, RESULTS OF FOUR
YEARS' WORK

I. The use, of sulphate of potash gave an increased yield of
0.9 tons per acre on the average of four years, over that of mu-
riate of potash.
2. On an average of four years, sulphate of ammonia gave
an increased yield of I.I tons per acre over dried blood.
3. The use of dried blood and muriate of potash gave an
increased yield of 1.56 tons per acre over muriate of potash and
acid phosphate.
4. For an average of four years, the use of ground limestone
gave an increase of 2.99 tons per acre.
5. Dried blood and muriate of potash gave an increase in
yield of 3.19 tons per acre over dried blood and acid phosphate.
6. There was a marked decrease in yield in all plots from
the first to the fourth year.
In the spring of 1911 three more plots of Japanese cane were
added to the fertilizer test. These additional plots were for the
purpose of getting more information on the results of ground
limestone applied to Japanese cane.
Table V shows the fertilizers in pounds per acre, the yields of
green forage per acre, the percentage of sucrose, and the Brix
readings for the years 1911 and 1912. As in the former experi-
ment, the use of ground limestone produced a heavier yield the
first year, but the second year there seems to have been no effect
from the use of ground limestone.







Annual Report, 1913


Plot I was given a complete fertilizer with the addition of
ground limestone. Plot II was given the same fertilizer without
limestone. The yield per acre of plot I was 50 per cent more than
that of plot II for the first year.
Plot III was not given a complete fertilizer, no acid phosphate
being applied, but it was given ground limestone. The yield from
this plot was not equal to that of plot I, but it was slightly heavier
than that of plot II.
As in the other experiment, all plots gave a much smaller yield
the second year than they did the first year.
From the behavior of the plots under observation, one is in-
clined to believe that it would be advisable to replant Japanese
cane as often as every three years if the maximum yields are to
be produced.
TABLE V
JAPANESE CANE FERTILIZER TEST. 1911-1912
SOUTH FIELD

Plot Plot Plot
I II III

Dried blood (lbs. per acre) ---- ------------ 112 112 112
Sulphate of potash ------ --------------- 84 84 84
Acid phosphate ----------- ------------- 224 224
Ground limestone ------- -------------- 2000 _------ 2000
Total fertilizer per acre --------------- 420 420 196
Yield tons green forage, 1911 ----- ------- 15.56 10.8 11.81
Yield tons green forage, 1912 ------------- 7.00 2.81 3.87
Average for two years ----- ---------- 11.28 6.84 7.84


Sucrose per cent, 1911 ---4.70 -4.24
Sucrose per cent, 1912 -------------------- 10.09 9.61


4.07
10.34


Brix, 1911 -------------- 13.80 13.70 13.4
Brix, 1912 -------------------- 15.30 15.10 15.30


JAPANESE CANE CULTIVATION TEST

We now have the results of three years' work in regard to how
shallow or deep cultivation might affect the yield per acre of Jap-
anese cane forage. However, few if any definite conclusions can
be drawn, except that all plots after the first year decreased in yield
considerably.
The plot cultivated two inches deep for an average of three
years yielded 14.97 tons -of green material per acre, this being 1.36


xxiii







Florida Agricultural Experiment Station


tons more than the other plots, the differences in yield of the other
plots being only about half a ton per acre.
From the results of this test it is safe to conclude that the depth
of cultivation has little effect on the yield of Japanese cane.
Table VI shows the depth the different plots were cultivated,
and the yield per acre.

TABLE VI
JAPANESE CANE CULTIVATION TEST-YIELD, TONS PER ACRE, GREEN MATERIAL

Plot Depth of cultivation 1910 1911 1912 Average of
three years.
I 2 inches deep ------------- 16.6' 13.30 13.02 14.97
II 4 inches deep --------- 16.5 13.14 10.45 13.36
III 6 inches deep ----------- 18.0 13.15 9.70 13 61

wards ------------------ 17.0 11.49 9.84 12.77


VELVET BEANS, CONTINUOUS PLANTING

In the spring of 1907, a test was begun to determine the re-
sults of continuous planting of velvet beans on the same plot of
ground.
We have now grown six continuous crops on this acre of land.
The results obtained are similar to what might be expected from
the continuous cropping of almost any other crop.
From these results it is probably safe to say that the best re-
sults would be obtained by planting velvet beans on the same piece
of land not oftener than every two or three years.
In getting the yield, the beans were picked by hand, and the
dry pods weighed. One hundred pounds of beans in the pod will
shell out sixty pounds, or one bushel of shelled beans.
The following yields were secured.
Bushels
1907 ................................................ 25.13
1908 ................................................ 14.77
1909 ................................................ 11.37
g19o ............... .. . ........... ........ ....... .... 13.90
1911 crop destroyed by caterpillars.
1912 ............................................... 9.63
A average ....................................... 14.96

The growth of vines from year to year seemed to be about
the same. When the growth of vines on the acre which was
planted to velvet beans continuously was compared with the growth


xxiv








Annual Report, 1913


of vines on land that had not grown velvet beans for several years,
there was no noticeable difference. The vines were not, however,
harvested and weighed.

YIELDS OF SWEET POTATOES

Table VII gives the yields per acre of several varieties. The
potatoes were divided into three classes: commercial, stock, and
strings. In the commercial size were included all potatoes large
enough for table use, that is over one half inch and under three
inches in diameter. The stock size included all potatoes over three
inches in diameter. The strings included everything under one-
half inch in diameter.
None of the varieties produced extra heavy yields during the
year 1912, the average yield for the eleven varieties being 148.o8
bushels. The weight per bushel was figured at 60 pounds.
The following amounts of fertilizer were applied per acre:

Pounds
Nitrate of soda ... ............................50
Sulphate of ammonia ................................... 70
Sulphate of potash. .......... ..................... 150
Acid phosphate ...................................... 400
Total ........................ ................... 670

The fertilizer was applied in the drill, and bedded on just be-
fore planting.
TABLE VII
YIELD OF SWEET POTATOES, I912

Bushels per acre
Name of Variety
Commercial Stock Strings Total
Porto Rico Yam ----- --- 138.12 113.25 13.5 264.87
Unknown ---------- 148.75 30.00 20.0 197.75
Red Yam ---------------- 93.33 36.94 15.0 145.27
Triumph --------- 135 83 40.41 12.08 188.32
Nancy Hall ---------- 84.16 35.83 8.33 128.32
Improved Golden ------ 30.00 11.60 26.66 68.32
Enormous ------------- 65.00 24.79 19.58 109.37
Nancy Hall ----------- 24.79 12.29 9.16 46.24
Big Stem Jersey _-- 111.18 111.18
Vineless ----------------- 49.87 27.38 31.52 108.77
Triumph ----- ---- 123.75 126.66 12.08 262.49
Average -------- 91.34 45.91 16.99 148.08


xxV







Florida Agricultural Experiment Station


SWEET POTATO SILAGE
A considerable quantity of sweet potatoes was put into the silo
last November when it was being filled with Japanese cane. This,
so far as the writer is aware, is the first time sweet potatoes have
been used as a silage crop. Hence it was difficult to predict what the
results might be. However, to our surprise, this silage kept in per-
fect condition. The sweet potatoes were treated the same as if they
had been Japanese cane or corn; that is they were run through the
ensilage cutter the same as any other material.
Dairy cows and hogs eat this silage with relish. There was no
waste in feeding it, for it kept perfectly, and there is but a small
percentage of coarse fiber in the sweet potato.
The results obtained with sweet potato silage proved so inter-
esting that it is planned to carry out some feeding experiments
during the coming year.
Where sweet potatoes are grown for feed it is often found
difficult to keep them through the winter season. If they can be
preserved in the silo there will be a saving, not only in the keep-
ing quality of the potatoes, but also in the storage room required.
Five hundred bushels of sweet potatoes, stored in the form of
silage, would not require one half the space occupied in a potato
bank.
CASSAVA SILAGE
Cassava was also put in the silo. This was treated in the same
way as the sweet potatoes; that is, it was run through the ensilage
cutter the same as any crop put into the silo.
The cassava silage kept in good condition; and, like the sweet
potato silage, it was relished by both cattle and hogs.
As a crop for Florida, cassava is not grown as generally as
sweet potatoes. It is also a more expensive crop to produce.
Under average farm conditions and on most soils, sweet potatoes
will yield from fifty to seventy-five per cent more than cassava.
In feeding value there is but little difference. Hence sweet pota-
toes are of more importance as a forage crop than cassava.
Respectfully,
J. M. SCOTT,
Animal Industrialist.


xxvi








Annual Report, 1913


REPORT OF PLANT PHYSIOLOGIST

P. H. Rolfs, Director.
SIR: I herewith submit the report of the Plant Physiologist
-for the fiscal year ending June 30, 1913.

BORDEAUX MIXTURE FOR THE CONTROL OF DIEBACK

In January, 1909, the Experiment Station planted a citrus
grove at Woodlea, near Tavares in Lake County, in co-operation
with Mr. G. M. Wakelin, for the purpose of determining the ef-
fects of certain fertilizers upon the soil and the trees. The grove
consisted of 480 trees of Valencia Late oranges budded on sour
orange stock. (Fla. Agri. Exp. Sta. Report for 1909, p. xxvi).
In July, 191o, Mr. Wakelin reported that the trees were gen-
erally affected with the citrus disease, Dieback. A close exami-
nation showed about 78 per cent. of them to be affected. The
disease was found to be in an early stage of development. In
March, 1911, the trees in the grove were again examined. It was
found that the disease had advanced greatly in development during
the latter half of the growing season of 1910. It showed renewed
development in the spring of 1911. (Fla. Agric. Exp. Sta. Re-
port for 1911, p. lxxii).
In November, 1911, another close examination of the trees
was made. The disease had again increased in severity with this
season's growth. A small percentage of the trees were so badly
injured by the disease which was followed by withertip (Colleto-
trichum gloeosporioides), that it was necessary to replace them
with new. trees. The number of trees showing the presence of
the purple scale (Lepidosaphes beckii) was large, but in only 28
trees were they present in sufficient number to do injury. In all
cases these scales were being attacked by the black and white
fungi (Myriangium duriaei and Ophionectria, coccicola), which
were holding them in check. Table VIII shows the numbers and
percentages of trees affected with the different symptoms of the
disease, or infested with the purple scale.
Owing to possible complications' that might interfere with the
experiment, no method of treatment had been attempted. But
since it appeared at this time that the disease would cause further
injury, it was decided to spray with Bordeaux mixture to control
it. Although the disease is not known to be caused by an organ-
inm. and is thought to be due to physiological causes, there is


xxvii








xxviii Florida Agricultural Experiment Station

evidence from practice and experiment that this spray is an ef-
fective remedy. Its action is explained by its stimulating effect
upon the tissues.
METHOD OF TREATMENT.-The trees were sprayed thoroughly
with Bordeaux of 5:5:50 strength, twice during the spring of
1912. The first application was made about February 8; the
next about April 15. Within ten days after spraying with Bor-
deaux, the trees were sprayed thoroughly with an insecticide in
order to control the scale insects which experiment and practice
has taught will greatly increase in number after the use of copper
sprays, on account of the killing of the entomogenous fungi which
hold the scale insects in control. As a check, the fifth tree in
each plot was left unsprayed. The work of this experiment was
done by Mr. G. M. Wakelin.
RESULTS.-In January, 1913, another examination was made
of the grove to determine whether any benefit had accrued from
the spraying. Table IX summarizes the notes made at this time,
showing the numbers and percentages of trees sprayed and un-
sprayed that were more or less affected by the different symptoms
of the disease. The table also enumerates the trees which showed
the presence of the citrus scale (Lepidosaphes beckii). The table
shows a larger percentage of the unsprayed than of the sprayed
trees to be affected with the different symptoms. The predomi-
nating symptom is the gum pocket, the other symptoms being
comparatively scarce. In no case was the disease found to be of
such severity that it was badly injuring the tree. In many cases
the different symptoms were found only after search.
Table X enumerates the percentages of affected trees for 1911
and 1912. A comparison of the percentage of affected trees in
1911 with that of those not sprayed during 1912, showed a very
material decrease of the Dieback that is not due to the treatment
with Bordeaux.. On the other hand, a comparison of the per-
centage of affected trees amongst those not sprayed, with that
amongst those sprayed, showed a great decrease due to. the effect
of the spray. The greater decrease of the superficial symptoms
(bark excrescences, stained terminal branches, and multiple buds)
is explained by the close association of the spray with the tissues
affected.
A comparison of the percentage of trees showing the presence
of the purple scale at the end of 1911, with those of the sprayed
and unsprayed trees at the end of 1912, shows a slight decreasi









Annual Report, 1913


xxix


among the sprayed trees and a large decrease among the check trees.
While there was a slight decrease of the number of trees showing
scale amongst the sprayed trees, these trees showed a heavier in-
festation than did those at the end of 1911.
In conclusion, it appears that the Bordeaux was effective as a
spray for the control of Dieback; but that its benefits were some-
what hidden by a decrease of the disease due to natural causes.
The effect of the insecticide used after the Bordeaux is marked by


the lack of any great increase of scale over
the experiment was started.


TABLE VIII.
NOVEMBER, 1911.


0

o
g
3


c
C)

^1 I

m99m
1CS $^
Sm (S


that existing before


C)
S
o


<;h


Trees affected -------- 392 354 312 283 No fruit 345
on trees *
Percentage affected --... 81.7 73.7 65.0 59 do. 77.8


TABLE IX.
JANUARY, 1913.





90
'5
I 'G




U0 C) Pq W r

Affected trees among
sprayed ------------ 111 20 10 0 4 302
Affected trees among un-
sprayed -------------- 27 15 13 1 1 8
Percentage affected trees
among sprayed -----. 25.7 4.6 2.3 0 0.93 69.6
Percentage affected trees
among unsprayed .- 56.2 31.3 27.1 2.1 2.1 16.7
Total number trees af-
fected --- -------- 138 35 23 1 5 310









xxx Florida Agricultural Experiment Station

TABLE X.
1911 AND 1912.


"Q 3
CCd
0'0





Percentage trees affected
Nov., 1911 -- 81.7 73.7 65 59 0 71.8
Percentage checks affect
ed Jan., 1913 ----- -- 56.2 31.3 27.1 2.1 2.1 16.7
Percentage sprayed affect
Percentage trees affected
Nov., 1911 -------.-- 81.7 73.7 65 59 0 71.8
Percentage checks affect-

ed Jan., 1913 ------ -25.7 4.6 2.3 0 9.3 69.9


GUMMING OF CITRUS TREES PRODUCED BY CHEMICALS

Certain groups of plants are characterized by a predisposition
to the production of gum. Such gum is a pathological product of
the living tissue, and its formation is induced by many factors,
such as injuries from insects, fungi, bacteria, and chemicals. The
citrus tree belongs to one of these groups, and many of its diseases
are characterized by the formation of gum. Dieback or exan-
thema is one of these diseases, and is thought to be a form of
chemical injury induced by certain poisonous products in the soil.
In the course of the investigation of this disease, an experiment
was carried out to determine the ability of certain chemicals to
induce gum formation. The results of this experiment are here
reported. H. S. Fawcett carried out a somewhat similar experi-
ment which he briefly mentions in Fla. Agr. Exp. Sta. Report
for 1912, p. lxxx. He found that a number of acids would induce
gum flow.
EXPERIMENT.-This, experiment was carried out in a nursery
row of five-months-old Pineapple orange buds on two-year grape-
fruit stock, during July to September. The trees were in a con-
dition of rapid growth. The spring growth was well hardened,
and the summer flush of growth was on. The weather conditions
prevailing during this period were warm with a normal rainfall.
Table XI shows the daily temperature, and precipitation.
Different organic and inorganic chemicals were placed beneath
the bark, or in holes in the trunk, or were painted on the surface of








Annual Report, 1913


the bark. No method of sterilization was used, except in one'group
of the series where the surface of the stem or trunk was washed
with sterile water before using the chemical.
For a definition of the terms lacuna, gum-cycle and gum-pocket,
as used in this paper, the reader is referred to the article on "Gum-
Pockets Produced by Dieback in Citrus Wood" (Fla. Agr. Exp.
Sta. Report for 1912, p. cv.).
RESULTs.-The first group of experiments was started on July
18. Five different trees were treated with each chemical. One series
of five trees was left without treatment, as a check. Except where
the chemical was painted on the bark, the point of insertion on each
tree was wrapped with tape soaked in grafting wax.
Enzyme (Diastase of Malt)-An extract was made of ten grams
of Diastase of Malt, and filtered. Enough of the filtrate was
poured into 95 per cent. alcohol, to dilute the alcohol to about 80
per cent. in strength. The precipitate obtained was used for the
following inoculations.
A hole was bored with.a small bit into the trunk of each tree just
below the bud union. (All trees used in these experiments were
budded about six inches above the ground.) A few drops of water
were added to the precipitated diastase making a thick viscous fluid.
The holes in four trees were filled with this fluid by means of a
pipette, and then closed tightly by waxed filter paper and grafting
wax. Pure water was placed in the hole of the fifth tree, which
was then closed as were the others.
On July 20, tree II showed beads of gum exuding from be-
neath the waxed paper. The gum was of a clear amber color,
and was completely soluble in water. None of the other plants
showed any evidence of gum formation.
On July .24, the waxed paper was removed from all trees, and
observations made as to evidence of gum formation. No gum
was evident to the eye on trees I, III, and IV; but on cutting a
segment from the wood and bark, there was a slight exudation of
gum from the exposed cambium region. The hole in tree II was
partially filled with gum, and the cambium region (exposed by
removing a segment from a point immediately above the hole)
showed a slight exudation of gum. Tree V showed no gum. for-
mation, either at the hole, nor from the cambium region exposed
by removing a segment.
Cross-sections were made of the segments removed from the
wood and bark above the holes in the different trees. The sec-
tions of the segments from the inoculated trees contained well-


xxxi








xxxii Florida Agricultural Experiment Station

developed gum-cycles in the embryonic xylem tissue adjacent to
the/ cambium. The cycle was composed of lacunae which were
in most cases individual. In the formation of the lacunae, cells
had disappeared, and the space had become filled with gum. The
bordering cells were rounded and somewhat enlarged, and were
in different stages of separation, with their protoplasmic contents
greatly increased in density and granulation. The gum-cycle and
lacunae here noted showed no difference, except in extent of de-
velopment, from those associated with the Gum Pockets of Die-
back (Fla. Agr. Exp. Sta. Report for 1912, p. cv). (See also
Fig. 3).


FIG. 3.-Gum-cycle produced by Dieback.


The sections from the segment from the check tree contained
normal xylem tissue, which showed no indication of the develop-
ment of a gum-cycle.
In some trees segments were removed at intervals along the
stock, from the hole to and beyond the bud union. The gum cycle
was found not to extend to the bud union.
On August 8, gum formation had ceased. No new gum cycles
had developed. The gum cycle noted above had become buried
beneath normal tissue. All wounds were healing.







Annual Report, 19r3


Acetic Anhydride.-Holes were bored into the stocks of five
trees, and the chemical inserted as in the previous series. Owing
to its rapid penetration, the anhydride did not remain long in the
holes. The tissue was killed wherever the chemical touched it,
turning a brownish color.
Previous to July 24 no gum formation was evident to the eye
on any of the trees. But, on this date, when the waxed covering
was removed from the holes, the hole in tree I was found to be
filled with gum. None of the holes in any of the other trees con-
tained gum. Tree II showed beads of gum along the margin of
the killed area on the stock. Tree IV showed no evidence of gum
formation, until on cutting a segment from the wood and bark,
gum exuded from the exposed cambium region. Trees III and
V showed no evidence of gum formation.
Cross-sections of the segments cut from the wood and bark
above the holes, and at intervals to beyond the bud union, showed
the presence of a gum-cycle in the cambium near the holes in
trees I, II, and III. This did not extend to the bud growth. (Fig.
4). No point of difference could be noticed between the gum-
cycle developed here and that developed by treatment with the


4 .c .pu y4 ct


;, ", .', Ki,, r.




.7 !, ..
1 .







-- .. -- 'i -





FIG. 4.-Gum-cycle produced by acetic anhydride.


xxxiii








Florida Agricultural Experiment Station


enzyme or that associated with the gum pockets of Dieback. Tree
IV showed a more extended injury than the others. Killed areas
were traced along the bud growth to the leaf tips on the upper
branches. A gum cycle was found in the embryonic xylem adja-
cent to the killed areas. Tree V showed no gum-cycle develop-
ment.
On August 8, gum formation had ceased. The embryonic
cells were normal. The gum-cycles above noted were covered
by normal xylem tissue.
Copper Sulphate.-A small crystal of copper sulphate about
the size of an 8-penny nail-head was placed beneath the bark on
the stock of each of five trees, a few inches above the ground.
The slit was then wrapped with grafting wax cloth.
On July 20, no gum flow was evident to the eye, except in tree
III, where the bud growth was recently torn from the stock by
the cultivator. Drops of gum were exuding from the exposed
cambium region.
On July'21, all trees in the series showed gum flow. Trees
I and II showed it exuding at intervals along the stock and bud
growth to the terminal branches. On the branches it exuded from
the leaf scars left by recently fallen leaves. (It is probable that the
leaf fall was the result of the gum formation at these points.)
A close examination showed the gum to be exuding from the ex-
posed cambium at the leaf scars. Trees IV and V showed some-
what similar but not so plentiful evidences of gum formation. On
tree III, gum exuded only at places where the cambium region
had been exposed by injury.
On July 23, gumming of the plants in the series continued.
Cross-sections of segments removed from the stock and bud growth,
along the line of gum manifestation, showed the development of
a gum-cycle and miniature gum-pockets in the embryonic xylem
tissue. No point of difference in appearance and development was
seen between this gum-cycle and those developed by Dieback, or
by the enzyme, or by acetic anhydride. The cells showed the
same increase in granulation and density. There was the same
rounding out,- increase in size, separation, and disappearance of
cells in the development of the lacunae. In the miniature gum-
pockets, adjacent lacunae had become united by the breaking and
disappearance of the separating medullary-ray cells. The cells
bordering on the pockets, including both the parenchyma and
medullary-ray cells were swollen, projected into the gum mass, and
....ron o..honrlpi hvr lls nrrianed in a ladder-like manner. The


xxxiv







Annual Report, 1913


pockets, however, had not developed to such a size that they raised
the bark and became evident from the exterior.
No gum cycle was developed where the cambium had been
killed by the chemical.
On July 24, all plants still showed active gum flow. Many
leaves had been killed and were falling. In one case the tips of
the branches were dying back. But not all branches were af-
fected, as several were apparently normal.
On July 25, there was copious gum flow and much chemical
injury on all of the plants. There was a young terminal branch
on tree I that showed no evidence of chemical injury, whereas the
old growth subtending it was defoliated, and showed injury and
much gum flow. (This had been noticed numerous times in cases
of chemical injury.)
On August 8, gum flow had ceased and the trees were rapidly
recovering from the chemical injury.
Sulphuric Acid.-In this experiment a 65 per cent. solution
of sulphuric acid was used. It was applied to five trees in spots on
the trunk and branches, with a camel's hair brush. Branches in
each tree were left untreated.
On July 19, no gum flow or gum-cycles were found.
On July 21, trees I, II, and III showed beads of gum around
the margins of the killed areas.
On July 22, trees I, II and III still showed active gumming,
the gum flowing down the stems in some places. Trees IV and
V showed a small amount of gum near the margins of the injured
areas.
On July 24, on removing the cortex of a burned spot with a
needle, it was found to be underlaid by a gum mass. Cross-sec-
tions were made through burned and adjacent areas. A well-
developed gum-cycle was found in the embryonic wood beneath
the burned areas, extending outward beneath the adjacent live
cortex to a distance of about one centimeter. Beneath the burned
area, a large gum-pocket was formed, from which gum exuded
through slits in the burned bark.
On July 25 to 27, gum flow continued from points near the
injuries.
On August 8, gum flow had ceased and the wounds were heal-
ing.
Potassium Hydrate.-A concentrated solution oP potassium
hydrate was applied, in the same manner as the sulphuric acid,


xxxV







Florida Agricultural Experiment Station


to five different trees. It produced dark greasy-looking areas on
the bark.
On July 19, cross-sections through a spot painted on an angu-
lar stem showed that the chemical had penetrated to the cambium.
Where the effect was the strongest, the cortical, bast, and cam-
bial cell-walls showed much swelling. The protoplasm of the af-
fected cells showed plasmolysis into a flat mass with the flat sides
towards the surface of the stem. No gum-cycle had formed.
On July 24, segments cut from the stems near the points of
injury showed the presence of a gum-cycle in the cambium region
and a slight exudation of gum therefrom. It is probable that the
gum-cycle was of early origin, but its development was not suf-
ficiently great to break the covering tissue and allow exudation.
Cross-sections of the segments showed the gum-cycle to be
the same in structure and appearance as those already described.
But, in this case, the cycle extended farther from the region of
dead tissue than did that produced by sulphuric acid.
On August 8, there was no gum flow. The wounds were
healing.
Gum from Gum-Pocket of Dieback.-
On August 3, sections through gum-pockets obtained from
young wood diseased with Dieback, and collected in Orange Ham-
mock on July 31, were used as inoculating material for this series.
The bark was raised on the stock and on the bud growth just
above the union, ard the sections with a small amount of gum
were placed beneath. The wounds were then wrapped with waxed
tape.
On August 12, no exudation of gum was observed, and cross
sections of segments removed at intervals from the stock and bud
growth did not show the presence of gum-cycles. No chemical
injury was produced by the inserted gum mass.
Check Series.-Five trees were included in this series. They
received no chemical treatment, but were mutilated by bruises and
cuts and by raising the bark.
On July 24, no gum formation was evident to the eye. Cross-
sections of segments showed the embryonic xylem to be normal.
No gum cycle was present. The bud growth of tree I had been
cut away. The surface was healing with no indication of gum
formation.
On August 8, no gum cycles had developed. The wounds
were drying up and healing.


xxxvi








Annual Report, 1913 xxxvii

The second group of experiments was started on August 6.
Only organic chemicals were used. Five trees were included in
each series. Each chemical was inserted beneath the bark on the
stock, or on the bud just above the union, and the wound was
wrapped with tape that had been soaked in grafting wax. After
the chemical was in place a drop of water was added to aid it in
going into solution.

Uric Acid.-
On August 12, no gum cycle had been formed. The wounds
were dry and were healing.

Glucose.-
Creatinine.-
Asparagine.-
Urea.-
On August 12, none of the trees in any of these series showed
any indication of gum formation. The chemicals had produced
no injury, and the wounds made by raising the bark were dry and
healing rapidly. Cross sections of segments removed from the
wood and bark contained no gum-cycles.

Hippuric Acid.-
On August 12, gum in slight amount was found exuding at
the points of insertion on all the trees. Segments were cut from
the wood and bark just above the insertion, and cross-sections
made. The sections showed the presence of a gum-cycle, which
was no different from those already described, except in extent
of development.

Check Series.-
On August 12, no gum exudation was evident. Cross-sections
of segments cut from the wood and bark showed normal xylem
without any gum-cycle.
The third group of experiments was started on August 17.
The salts used for this group were those of the heavy metals. The
bark was raised on the stock, or on the bud just above the union,
the chemical was placed beneath, and the wound wrapped with
tape soaked in grafting wax.

Potassium Iodide.-
On August 20, trees I and IV showed gum flow from beneath
the wraps.








xxxviii Florida Agricultural Experiment Station


On August 21, all trees showed gum flow from beneath the
wraps, and all but tree III showed exudations at intervals on the
branches of the-bud growth. Chemical injury had extended into
the upper branches.
On August 24, cross-sections of segments showed gum cycles
developed in all. They were the same as these that have already
been described.
Lead Phosphate.--
On August 24, none of the trees showed any exudation of
gum. Cross-sections of the stems showed no gum-cycles to have
developed. On removing the wraps the chemical was found un-
changed, and no chemical injury apparent. It is probable that
none of the chemical was absorbed.

Ferrous Sulphate.-
On August 19, tree III showed a small amount of gum exud-
ing from near the point of insertion.
On August 20, all trees showed a somewhat copious gum flow
from the points of insertion. Trees I, III and IV had gum exud-
ing from cuts made about four inches above the insertions. Cross-
sections showed gum cycles in the embryonic xylem, which were
the same as those already described.
On August 24, gum flow continued. Chemical injury had
extended to the upper branches on two of the trees. Gum was
exuding at intervals on the branches, near the chemical injuries.

Copper Sulphate.-This series is a repetition of the one started
on July 18.
On August 17 to 24, the extent of chemical injury, the exudation
of gum, and the gum-cycles developed were about the same as
those that have been described for that series.

Mercury bichloride.-On August 19, tree V showed chemical
injury on stem about ten inches above the insertion. No gum
exudation was evident on any of the trees.
On August 20, all trees showed a small amount of gum exud-
ing from beneath the wraps.
On August 21, there was chemical injury along the bud growth
of all the trees, which extended to near the tips of the terminal
branches. All but tree III showed exudation along the lines of
chemical injury, and from leaf scars of recently fallen leaves.
On August 24, an immature branch on tree I showed a large







Annual Report, 1913


well developed gum-pocket beneath a leaf node. In gross ap-
pearance and microscopical structure, it is exactly the same as
those produced by Dieback. (Fla. Agr. Exp. Sta. Report for
1912, p. cv.). Gum exudation continued. The terminal branches
were being killed by the chemical.

Silver Sulphate.-
On August 19, tree II showed chemical injury extending about
one inch above the point of insertion. Tree III showed gum exud-
ation at the point of insertion.
On August 20, trees III, IV and V showed chemical injury
that was extending upward into the tops. Gum was exuding from
beneath the wraps. The other trees also showed chemical injury,
but no gum flow.
On August 21, there was copious gum flow from the points
of insertion, and other wounds on the stock, but there was none
on the bud growth except on that of tree I. Chemical injury
had extended into the branches of all.
On August 24, there was copious gum flow from the stocks,
and at intervals along the branches of the bud growth. Cross
sections of the stems showed gum-cycles that were identical in
character with those that have already been described.

Check Series.-
On August 17, the trees in this series were treated the same
as those of the other series in this group, except that no chemical
was inserted beneath the bark.
On August 24, no gum exudation had occurred on any of the
trees. Cross-sections showed no gum-cycles. The wounds were
dry and were healing.
A fourth group of experiments was started on August 30.
Only organic chemicals were used, except copper sulphate, which
on account of its constancy in gum production was used as one
of the checks. The bark was raised on the stock or on the bud
growth just above the union, and the chemical inserted. The wound
was then wrapped with waxed tape.

Hippuric Acid.-
On September 2, there was a slight exudation of gum from
the points of insertion on all of the trees except tree II.
On September 3, there was a rather copious gum flow at the
points of insertion and at points where the cambium had been


xxxix







Florida Agricultural Experiment Station


exposed near the insertions by the removal of segments, except
on tree II. On tree II there was a slight exudation of gum near
the insertion.
On September 6, gum flow continued, but not copious. Cross-
sections showed the gum-cycle to be the same as those already
described.

Asparagine.-
On September 2, there was no gum flow evident on any of
the trees.
On September 3, there was a slight amount of gum present at
the point of insertion on tree I.
On September 6, there was no further indication of gum for-
mation. There was a fungus growth present in the wounds of
trees III and V.

Succinic Acid.-
On September 2, tree I showed a small amount of chemical
injury at the point of insertion. There was a trace of gum at
that point on tree IV.
On September 3, trees II, III, IV and V showed rather copious
gum flow at the point of insertion. Tree I showed a small amount
at the insertion and at a point immediately above where the cam-
bium had been exposed by a cut.
On September 6, cross-sections made of segments removed
from near the insertions showed the gum-cycle to be identical
with those produced by other chemicals.

Check Series.-No chemical inserted.
On September 6, there was no evidence of any gum forma-
tion. The wounds had dried and were healing.

Copper Sulphate Series.-
On September 3, all trees showed chemical injury and copious
gum flow at intervals along stock and bud growth to tips of the
branches.
On September 6, gum flow .continued. Cross-sections showed
the same gum cycle as has been described before.

Xanthine.-
On September 6, no gum flow was evident. Cross sections did
not show the presence of any gum cycles.








Annual Report, ipr3


Glycocoll.-
On September 3, there was a small amount of gum at the points
of insertion on trees I, II and III.
On September 6, there was no further flow of gum from trees
I, II and III. Cross-sections of segments removed from near
the insertions showed gum-cycles in trees I to III, but none in
trees IV and V.

Indol.-
On September 2, all trees showed a small amount of gum at
the points of insertion.
On September 3, tree II showed a rather copious gum flow at
the insertion. The others showed no change.
On September 6, cross-sections of segments removed from
near the insertions showed gum-cycles that were no different from
those described.

Tyrosine.-
Leucine.-
On September 6, none of the trees in any of these series showed
any gum formation. Cross-sections showed no gum-cycles to
have developed.
A fifth group of experiments was started on September 3.
Five trees were included in each series. The chemicals were in-
serted beneath the bark' on the stock, or on the bud growth just
above the union and the wounds then wrapped with waxed tape.
Only inorganic chemicals were used in this group. The chemicals
used are as follows:

Ammonium sulphate, Copper sulphate,
Ammonium nitrate, Sodium nitrate,
Mono-ammonium phosphate, Potassium sulphate,
Ammonium chloride, Potassium nitrate,
Potassium chloride.

A check series was also included which received no chemical
treatment.
On September 6, none of the trees in any of the series except
those in the Copper Sulphate series showed any indication of gum
formation. The trees in this series showed a small amount of
gum exuded at the points of insertion. Trees III and V showed
gum exuding also at points on the branches of the bud growth.
On September 9, the following trees showed gum exudation
at the points of insertion:









Florida Agricultural Experiment Station


Sulphate of ammonia. Trees II and III.
Mono-ammonium phosphate. Trees I, II, III, IV and. V.
Copper sulphate. Trees I, II, III, IV and V.
Sodium nitrate. Trees I, II and III.
Potassium sulphate. Tree III.
Potassium nitrate. Tree IV.

In all cases, except the Copper Sulphate series, the gum exuded
was small in amount and confined to the point of insertion. The
trees of the Copper Sulphate series showed copious gum flow at
the insertion and at intervals to the tips of the branches.
Cross-sections showed the presence of gum-cycles in all trees
showing gum exudation. These cycles showed no difference from
those produced by other chemicals. The embryonic xylem in all
trees not showing gum exudation was normal and free from gum
cycle development.
On September 12, the young growth on trees II, III and IV
of the copper sulphate series showed several large well-developed
gum-pockets. They were the same in appearance, structure and
location as those produced by mercury bichloride and by Dieback.


TABLE XI.

Precipitation. Experiments.
0.18 First series started.










0.10o



0.07
0.25
0.30
0.50
0.30
0.50 Second series started
0.62

o.89
.




0.10
1.00
o:o6


Date of Gumming
from


Malt diastase
Sulphuric acid,
copper sulphate

Potassium hydrate
acetic anhydride


d.





Hippuric acid


Temperature.
Max. Min.
87 70
91 71
92 71
93 72
91 70
92 70
95 75
94 76
93 78
96 70
96 76
93 72
93 72
91 76


Date.
July-
18 ......
19 ......
20 .....
21 .....
22 .....
23 .....
24 .....
25 .....
26 ......
27 ......
28 ......
29 ......
30 ......
31 ......
August-
I . . .
2 ......
3 ......
4 ......
5 ......
6 ......
7 ......
8 ......
9 ......
I.








II ......

12 ......
13 ......
14 ......
15 ......
16 ......
12.
13.
14 ...









Annual Report, 1913


Precipitation. Experiments.
0.02 Third series started.



0.08

i.41
0.53
0.07
o.31

0.67
0.02
o.oI Fourth series started


Date.
July-
17 ......
18 ......
19 ......
20 ......
21 . . .
22 ......
23 ......
24 ......
25 ....
26 ......
27 ......
28 ......
29 ......
30 ......
31 ......
September-
I ......
I.
2 ......
3 ......
4 ......
5 ......

6 ......
2 ......
8 ......
9 ......
10 ......
II ..... :
12 ......
13 . . .
14 ......
15 ......
'5.


Fifth series started


0.03
o.o3
1.07
o.31
0.51
0.30
0.24
1.03
0.90



DISCUSSION OF RESULTS


Date of Gumming
from


Silver sulphhte,
ferrons sulphate.
Mercury bichloride
potassium iodide.

Gum-pocket from
mercury bichloride.


Temberature.
Max. Min
92 73
91 70
91 70
92 72
93 72
93 71
91 70
83 69
90 70
90 70
88 72
85 70
87 68
91 69
91 71


Succinic acid, hip-
puric acid, indol.
Copper sulphate,
asparagine, gly-
cocoll.
Copper sulphate


Ammonium sul-
phate
Mono-ammonium
phosphate
Copper Sulphate
Sodium nitrate
Potassium sulphate
SPotassium nitrate


An enzyme and twenty-eight different organic and inorganic
chemicals have been used in this experiment in an effort to .in-
duce gum formation. Of this number thirteen induced a forma-
tion of gum. A review of these shows that most of them are classed
as acids, alkalies or salts of heavy metals.
The production of gum was.coincident with the injury caused
by the chemical. The most copious production of gum was caused
by copper sulphate and the other salts of the heavy metals, and
the injury extended from the point of insertion in the bud or
stock to the upper branches.
The injury caused by the other compounds was confined to the
region of insertion. The amount of gum formed in this case was
small, and gum production was associated with the place of chemi-
cal injury.
In all cases the gum was the same in character and appear-
ance. It was of a clear amber color, and was completely soluble
in water.


d.


0.05

0.07







xliv Florida Agricultural Experiment Station

A microscopical examination showed that in all cases the gum
originated in the live embryonic xylem tissue outside the dead
area produced by the chemical. It was produced in a gum cycle
whose development was identical with that found in citrus stems
diseased with Dieback. (Fla. Agr. Exp. Sta. Report for 1912,
p. cii).
The enlarged gum-pockets produced in the immature branches
of the trees inoculated with copper sulphate and mercury bichlo-
ride, which are an advanced and local development of the gum-
cycle, are no different in development, structure and external ap-
pearance from those produced by Dieback. A study of the weather
chart shows these structures to have been developed during a
rainy period when the temperature was high and when there was
much moisture in the soil and air. It is probable that. a decrease
in transpiration at a period when the water absorption is large is
favorable to the production of these structures.
Through the swelling of the gum collected in the gum-cycle
from absorption of water, pressure is developed. If the covering
tissue is inelastic, a break will occur and the gum exudes. This
point of weakness may be when the cambium is exposed, as at a
leaf scar, or where it has been exposed by a cut or injury. On
the other hand, if the tissue is elastic, as in the immature branches,
the covering tissue is raised and the enlarged gum pocket is seen
as a large, blister-like structure on the stem.
That pressure is developed by the swelling of the gum is shown
by the gum exuding in the form of a spiral from a minute break
in the bark. If the break had not occurred an enlarged gum
pocket would have formed at this place. The stem was from one
of the trees in the mercury bichloride series, and the exudation
was found on the morning of August 24, at the same time that
the gum-pocket was found.
The gum-cycle developed in the inoculated trees between two
and three days after the chemical was inserted. In no case was
it found within twenty-four hours after inoculation. The gum-
cycle is always found in the first embryonic xylem tissue laid
down by the cambium after the injury.
SAND CULTURES OF CITRUS SEEDLINGS
Although numerous experiments have been carried out in the
field to study the effect of different fertilizer combinations on the
growth of the citrus tree, there is little information as to the ef-
fect of these where carried out in pot culture under controlled







Annual Report, 1913


conditions in the greenhouse. Owing to the varying environ-
mental conditions, it is not always possible to arrive at the funda-
mental information sought by such experiments when they are
carried-on in the field; whereas, in the greenhouse, where these vary-
ing factors can be controlled, the various treatments are exactly com-
parable. In other words, in the field, the effect of the fertilizer
treatment is modified by the varying environmental factors; where-
as, in the greenhouse, the effect of the treatment is not disturbed
by these factors because they are maintained uniform. Therefore
a fertilizer experiment carried out either in the field or green-
house alone is not sufficient, but it should be carried out in both
places in order to be complete.
This report embodies the result of a preliminary experiment
carried out in the greenhouse to determine the effect of varying
sources of ammonia and phosphoric acid upon the growth of
grapefruit seedlings. Some of the series are a counterpart of
certain plots in the Experimental Grove (Fla. Agr. Exp. Sta.
Report for 1909, p. lxxviii).
A system of measurements of the different plant parts has been
carried out in order to determine quantitatively the variation in
growth due to the different treatments.
EXPERIMENT.-This experiment was conducted on the east
bench of the greenhouse, where light conditions were uniform.
It consisted of 18 series of five pots each. (The experiment origi-
nally consisted of 19 series, but one series-Nitrate of Soda and
Basic Slag-was lost through accident). Six-inch pots that had
been heated and soaked in melted paraffin were used. The sand
used was a coarse white sand secured from the shores of Lake
Weir in Marion County. The seeds planted were from grape-
fruit obtained from one tree.
On January 27, 1913, the pots were filled with sand to a uni-
form height, placed in position on the bench, and the fertilizer
applied.
The amount of fertilizer applied to the soil in each pot was
intended to approximate that applied to the tree in the Experi-
mental Grove at Tavares, which was two pounds to each tree.
Allowing six square feet as the space covered by the fertilizer
around each tree in the grove, 20 grams was calculated to be the
amount of complete fertilizer that should be used in each pot of
this experiment. The formula used for making up the fertilizer
was also the same as that used for the Experimental Grove, name-
ly, 5 per cent. of ammonia, 6 per cent. of phosphoric acid and 6









Florida Agricultural Experiment Station


per cent. of potash, with the exception that where nitrate of potash
was used as a source of both ammonia and potash the formula
used was 5:6:14.5. Where only one fertilizer constituent was
used, the amount of that constituent applied to each pot was that
contained in the complete fertilizer. Table XII shows the sources
and amounts of the fertilizer constituents, etc., used in the pots of
each series.
The lime used was air-slaked. It was applied along with the
fertilizer, except in the case of Series XII, where it was applied
on February 1o.
The fertilizer was scattered evenly over the soil surface, and
then mixed with the soil with a hand weeder.

TABLE XII

SOURCES AND AMOUNTS OF FERTILIZER CONSTITUENTS APPLIED


Series. Ammonia. Phosphoric Acid Potash. ILime.


I1 Sulphate of ammonia
5 g.
II Sulphate of ammonia
5 g.
III Sulphate of ammonia
5 g.
IV Nitrate of soda ---
6 g.
V Nitrate of soda ._--
6 g.
VI Dried blood -------
5.5 g.
VII Dried blood ..-----
5.5 g.
VIII Dried blood .------
5.5 g.
IX Nitrate of potash__
S7-5 g.
X Nitrate of potash_--
7-5 g.
XI Nitrate of potash__-
7.5 g.
XII Sulphate of ammonia
5 g.
XIII Dried blood ---- ..
5.5 g.
XIV ------------...

XV Sulphate of ammonia
S5 g.
XVI Nitrate of soda --
6 g.
XVIII ---.- --__________

XVIII No fertilizer .--.-


Acid phosphate- H. G. sulphate of
7.5 g. potash 2.5 g._-
Dissolved bone H. G. sulphate of
black 7.0 g. potash 2.5 g.__
Basic slag ----- H. G. sulphate of


6.6 g.
Acid phosphate-
7.5 g.
Dissolved bone
black 7.0 g.
Acid phosphate-.
7.5 g.
Dissolved bone
black 7.0 g.
Basic slag -----
6.6 g.
Acid phosphate.
7.5 g.
Dissolved bone
black 7.0 g.
Basic slag -----
6.6 g.
Acid phosphate-
7.5 g.
Acid phosphate-
7.5 g.
-- - -- -- -


potash 2.5 g.__
H. G. sulphate of
potash 2.5 g.__
H. G. sulphate of
potash 2.5 g.__
H. G. sulphate of
potash 2.5 g._
H. G. sulphate of
potash 2.5 g.__
H. G. sulphate of
potash 2.5 g.__
See first column.

See first column.

See first column.

H. G. sulphate of
potash 2.5 g._-
H. G. sulphate of
potash 2.5 g.__


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

------ H. G. sulphate of
potash 2.5 g.__









Annual Report, 1913


xlvii


TABLE XIII.
MEASUREMENTS MADE APRIL 25, 1913

0

8 Stem Length Leaf Length Leaf Breadth
,


A B

I 37.5 158
II 39.5 166
III 44.0 185
IV 46.0 i193
V 43.5 183
VI 48.0 200
VII 43.5 183
VIII 46.0 193
IX 40.0 168
X 42.0 176
XI 51.0 214
XII 42.0 176
XIII 48.0 200
XIV 48.0 200
XV 39.0 164
XVI 33.0 139
XVII 35.0 147
XVIII 24.0 100


15 23.7 142
13 24.4 146
7 27.0 162
5 26.2 157
8 27.0 162
2 30.8 185
9 27.4 166
6 29.8 179
12 26.5 159
10 27.0 162
1 30.0 180
11 27.0 162
3 29.0 174
4 27.8 167
14 23.3 139
17 18.0 108
16 18.3 110
18 16.6 100


C

14
13
7
12
8
1
6
3
11
9
2
10
4
5
15
17
16
18


A

12.3
13.6
16.0
14.8
15.0
19.0
17.0
17.7
14.5
15.7
17.8
15.5
17.8
16.8
14.1
11.0
11.7
10.8


B

114
126
149
138
140
177
158
165
135
146
166
143
166
156
131
102
109
100


C

15
14
7
11
10
1
5
4
12
8
2
9
3
6
13
17
16
18


D

15
13
7
10
8
1
6
4.
12
9
2
11
3
5
14
17
16
18


A.-Average measurements in millimeters.
B.-Relative measurements (check series, 100).
C.-Relative positions.
D.-Avefage positions.

TABLE XIV.

AVERAGE POSITION OF ALL MEASUREMENTS MADE IN APRIL


Sulphate of ammonia ----------- 15 13 7 11 -- 14*
Nitrate of soda ------------------ 10 8 ---- ------ ------ 17*
Dried blood -------------------------- 1 6 4 3 ---- -----
Nitrate of potash ------------ 12 9 2 ---- ---- ---
None ------------------------------ --------- ------ ------ 5* 18*
H. G. sulphate of potash ------------ --- -------- -- ------ 16*

*All combinations included 'H. G. sulphate of potash except those
marked with an asterisk.








Florida Agricultural Experiment Station


The seed was planted at a uniform depth of one and a half
inches on February 14. The pots were then mulched with sphag-
num moss, which was allowed to remain until March 18, when all
the seeds had germinated and the plants were above ground. Three
seeds were planted in each pot. After the plants were up it was
found that many of the seeds had developed two plants. The
apparently weaker plants were pulled up, leaving three plants in
each pot.
Results.-The first measurements were made on April 25, at
which time the lengths of the stems, and the lengths and breadths
of the leaves were determined. (See Figs. 5 and 6). Table XIII
shows the average measurements of each series, the relative meas-
urements in reference to the Check Series No. XVIII, and the
relative positions in reference to the series giving the greatest
measurement. The last column in the table shows the average
position of each series, and is obtained by determining the aver-
age of the positions the particular Series occupies in the different
groups of- measurements.
Table XIV shows the average positions of the different series
arranged for easy inspection; From this, it is seen that the com-
bination of dried blood and acid phosphate gave the best growth
(Fig. 6). The addition of lime was a hindrance, the growth
being only slightly better than that where lime was used without
any fertilizer. The combination of sulphate of ammonia and acid
phosphate (Fig. 5) gave the poorest growth of any of the different
combinations. The addition of lime improved the growth some-
what, but lime used alone gave a much better growth. Nitrate of
soda and nitrate of potash averaged close together as to the growth
produced. Basic slag appeared to be the better source of phosphoric
acid for use with sulphate of ammonia and nitrate of potash (Fig.
5), but only second best with dried blood.


xlviii






fON U e SU'-P' r PR r1H.'.Tt.


F


H. C S'.IF *TjY "


V.


_ Ft. -. -^'" 74 3.* 7 -


FIG. 5.-Grapefruit seedlings in sand cultures. Nos. I and XI.








I.. Ir. PHOPFHI4.TE H (1, SULPH.AT1E OF PrOTAH. H


, .... r *- .I. 0
i V .1 '


r -,C( V
I. -.

V I.


FIG. 6.-Grapefruit seedlings in sand cultures. Nos. VI and XVIII.


V


t i
.l.... i 'r.L 'Clt.,J'.i"


.. ;, ,,,.







Annual Report, 1913 li

By June o1, 1913, the plants had completed their first flush
of growth, and the experiment was closed. Measurements were
again taken as in April, except that they were extended so as to
include the diameter of the stems just above the ground, and the
fresh and dry weights. Table XV shows the measurements and
positions of each Series.
Table XVI shows the average positions arranged in a form
for easy inspection. Again, dried blood shows.itself as the best
source of ammonia for combination with the different sources of
phosphoric acid. The plants fed with dried blood and acid phos-
phate gave the best growth. The next best growth was where
lime was added, whereas the series fed with lime alone fell to
twelfth place. Sulphate of ammonia with acid phosphate and dis-
solved bone black gave poor growth, whereas with basic slag and
with lime a better growth was evident. Nitrate of soda and ni-
trate of potash averaged about the same.










TABLE XV.
MEASUREMENTS MADE JUNE IO, I913


Series Stem Length Stem Diameter Leaf Length Leaf Breadth Fresh Weight Dry Weight
No.


I
"I
III
IV
V
VI
VII
VIII
IX
x
XI
XII
XIII
XIV
XV
XVI
XVII
XVIII


A

49.9
51.5
88.2
70.1
91.0
110.0
92.8
82.1
63.6
85.0
82.4
86.4
92.0
.58.2
52.6
47.0
42.6
30.6


B C

165 15
170 14
291 5
231 9
300 4
363 1
306 2
271 8
210 11
231 10
272 7
285 6
304 3
192 12
174 13
155 16
141 17
100 18


A B

1.56 119
1.66 127
2.22 170
2.02 155
2.29 175
2.51 192
2.35 180
2.48 190
2.13 163
2.43 186
2.50 192
2.36 181
2.38 182
2.27 174
2.00 153
1.61 123
1.55 119
1.32 100


C

16
14
10
12
8
1
7
3
11
4
2
6
5
9
13
15
17
18


A B

29.6 163
31.0 170
47.7 262
38.4 211
45.6 251
54.5 300
49.5 272
46.3 255
37.7 207
47.6 262
44.0 242
44.7 246
49.0 270
32.7 180'
29.8 164
26.6 146
25.0 138
18.2 100


C A

15 14.0
13 14.6
5 21.0
10 17.7
7 19.8
1 23.4
2 21.7
6 21.2
11 17.2
4 20.8
9 20.4
8 19.4
3 21.9
12 17.0
14 15.0
16 13.7
17 13.7
18 11.0


B C

127 15
133 14
191 5
161. 10
180 8
213 1
197 3
193 4
157 11
189 6
186 7
177 9
199 2
155 12
137 13
125 16
125 17
100 18


A B

.72 124
.85 146
2.51 432
1.60 275
2.31 307
3.24 557
2.99 514
2.98 513
1.77 304
2.81 483
3.00 516
2.61 449
3.61 544
1.55 267
1.51 260
1.05 181
.91 157
.58 100


C

17
16
8
11
9
1
4
5
10
6
3
7
2
12
13
14
15
18


A

.19
.21
.61
.37
.54
.77
.71
.74
.41
.65
.70
.59
.77
.41
.38
.23
.20
.13


B

146
162
470
285
416
593
547
570
316
500
539
454
593
316
293
177
154
100


C D

17 16
15 14
7 7
13 11
9 9
1 1
4 3
3 4
10 10
6 6
5 5
8 8
2 2
11 12
12 13
14 15
16 17
18 18


A.-Average measurements in millimeters.
B.-Relative measurements (check series, 100).
C.-Relative positions.
D.-Average positions.


r


------









Annual Report, 1913 liii

TABLE XVI.
AVERAGE POSITION OF ALL JUNE MEASUREMENTS


Sa

0




Sulphate of ammonia ------ 16 14 7 8 13
Nitrate of soda --------------- 11 9 -------- 15*
Dried blood -----------------1 3 4 2 -- ---
Nitrate of potash ------------------ 10 6 5 --- -
None --------- --------------- ---------------- 12* 18*
H. G. sulphate of potash --------- -- ----------------- 17*

*All combinations included H. G. sulphate of potash except those
marked with an asterisk.

Respectfully,
B. F. FLOYD,
Plant Physiologist.








liv Florida Agricultural Experiment Station

REPORT OF ENTOMOLOGIST
P. H. Rolfs, Director.
SIR: I herewith submit the report of the work in the Depart-
ment of Entomology for the year ending June 30, 1913.

FURTHER SPRAYING EXPERIMENTS WITH MICROCERA
The spraying experiments with this fungus, which is the main
cause of natural mortality of whitefly, commenced in January,
1912. A detailed description of these experiments appeared in
the annual report for 1912. The work was continued up to Jan-
uary, 1913. It was thought desirable to continue these experi-
ments over a year in order to determine what weather conditions
were most favorable for the growth of the fungus.
The spores were gotten from cultures on sweet potatoes, and
sprayed into the young trees as before. In addition, whole twigs
were dipped in the water containing the spores in suspension.
The general results were about the same as those tabulated
in last year's report. For these experiments it was never possible
to obtain leaves that remained free from natural mortality. Hence
it was necessary to take the difference between the percentage of
dead larvae on the sprayed and on the unsprayed portions as a
measure of the efficiency of the fungus. Spraying with spores of
Microcera generally caused marked increase in the amount of
natural mortality on the sprayed leaves as compared with that on
the checks. During the markedly dry weather, such spraying or
dipping-had an effect so slight as to come within the margin of
possible error. The most marked results were obtained with ma-
terial sprayed on September 21, 1912. On September 24 the
sprayed section showed that 8 per cent. of the total number of
larvae had died (counting only those that had recently died as
indicated by the color), as compared with 3.6 per cent. and 2.75
per cent. on the checks on either side. On September 26, the
percentage of dead on the sprayed leaves had risen to 21.6; while
on the checks it was 3.2 and 2.8 respectively. In these experi-
ments some of the checks were left unsprayed, and others were
sprayed with water free from spores. The object was to see if
mere wetting had any effect on the increase of Microcera. No
difference could be seen between the unsprayed leaves and those
sprayed with water.
The response to spraying with spores of Microcera was very







Annual Report, 1913


prompt, as compared with either Aschersonia or Aegerita, Mic-
rocera often appearing, as in the above instance, in three days.
The difference in the percentage of dead larvae on the sprayed and
on the unsprayed portions usually reached its maximum in from
five to ten days after spraying. This short period of time agrees
with the time the fungus requires to develop on artificial media.
On sweet potatoes 24 to 60 hours is sufficient to start a good growth.
The spores are abundant a day or two later. Aschersonia, on the
same media, seldom shows any signs of spore formation before
a month after inoculation. This is about the average length of
time required for its appearance in the grove after spraying. The
percentage of dead larvae as compared with live ones is low in
all these experiments. This was doubtless due to the unfavorable
nature of the material experimented on, which consisted of young
nursery stock planted in rows where moisture conditions were
much less favorable for fungus growth than in trees in a grove.
Furthermore, the experimenter purposely picked out plants that
showed a low percentage of infestation. In any grove it is easy
to find leaves with a much higher percentage of natural mortality.
That the low percentage was due largely to unfavorable situation
was farther indicated by the fact that it was possible to get As-
chersonia started in these trees only after repeated attempts, and
that attempts to introduce Aegerita were uniformly unsuccessful.
Over-crowding is an important predisposing condition for a
high percentage of infection, in any parasitic disease, since the
parasite can spread more rapidly from one-individual to another
when they are' close together. I have, however, found no evi-
dence to support the idea advanced by some that death was due in
any case to over-crowding or lack of food. (U. S. Dept. of Agr.,
Bur. of Ento., Bul. 102.) It is easy to find larvae with their bodies
actually over-lapping, and yet perfectly healthy. As compared with
A. inconspicua on papaya leaves, the infestation of A. citri on citrus
leaves is never heavy.









Ivi Florida Agricultural Experiment Station

TABLE XVII.

PERCENTAGES OF DEAD WHITEFLY ON INFESTED LEAVES DIPPED, (A) IN A SUSPEN-
SION OF SPORES FROM A CULTURE OF MICROCERA, AND (B) IN A SUSPENSION
OF FRAGMENTS OF LARVAE WHICH DIED FROM "NATURAL MORTALITY."

Dipped Jan. 31


Material used.


(A) Culture of microcera


(A) Culture of microcera


Check (not dipped) _-- ___


(A) Culture of microcera ----


Check (not dipped


(B) From "natural


mortality" _-_


Total dead
Recent.--..


Total ---
Recent --.

Total ---
Recent --.

Total ---
Recent --.


i I -


Total ---
ocent_

Total ---
Recent-...


10.5 13.9
0.8 4.8

19.0 '20.3
1.3 5.4

7.5 10.0
0.3 2.0

12.1 16.0
0.5 5.2


39.7
12.5

15.6
1.2


16.8 17.2
7.6 8.0

20.6 17.4
7.0 4.0

10.1 9.2
4.0 3.3

16 17
5.2 5.2

38 36.7
113 1 .4

15 11.8
3 3


1522


1071


178


438


265


341


Dipped Feb. 18


>
Material used I !Cd

ci a ci ci gi g


(A) Culture of microcera --- Recent 1.6 6.2 "8.5 3.2 4 609
(A) Culture of microcera ---- Recent 2.2 4.5 4.7 2.2 1.2 859
(A) Culture of microcera ---- Recent 2.8 4.2 5.1 5.1 4 140
Check (not dipped) -------- Recent 1.4 0.7 6.4 5.1 0.7 140
Check (not dipped) -------- Recent 2.6 2.7 6.7 5.8 2.2 1749
(B) From "natural mortality"- Recent 1.2 .... 4.1 2.3 2 942
(B) From "natural mortality"- Recent 1.8 4.6 5.4 3.8 4 1745
(B) From "natural mortality"_ Recent 1.0 2.1 3.6 3.6 2.7 1768


---I----









Annual Report, 1913

TABLE XVII--(Continued).
Dipped March 3


Material used


Check (not dipped) -------------Total dead 12.8 12.8 8.6
Recent---. 1.8 5.8 3.3
(A) Culture of microcera -------- Total ..-- 8.2 13.1 13.2
Recent --. 3.1 8.5 5.4


(A) Culture of microcera ----.-


Total _--_
Recent----


12.6 20.6
1.7 9.9


15.8
5.4


0 0
[-U

842

803


Dipped March 7



Material used

cl E- U
s | | a


(B) From "natural mortality" -


Total dead
Recent-...


Check (not dipped) ------------Total 16.0 16.1
Recent .. 1.6 0.5
(B) From "natural mortality" --Total 14.2 18.7
Recent--.. 1.7 5.1


From old "natural mortality" ___


Total ----
Recent-...


7
3.4

14.9
0.4
13.4
4.7
12.5
5,7


1064

1432

3618

1426


It was thought that the virulence of Microcera might have been
lowered as the result of growth on artificial media. To determine
this point a long series of spraying and dipping experiments was
run. In these experiments some twigs were sprayed or dipped
in a suspension of spores from the culture. Others were similarly
treated with water in which the victims of natural mortality had
been broken up, and still others were treated with clear water or
left untreated as a check. The results of one typical experiment
are given in Table XVII. By "old natural mortality" it is meant
that there were rubbed up in the water larvae that showed by







Florida Agricultural Experiment Station


their color that they had been dead for some time, while in the
fresh material the larvae were still of the deep brown color char-
acteristic of these that have but recently died. The last column
gives the totals of larvae counted. Under the date of dipping is
also given the percentage of dead on the leaves on the day the
dipping was done. It is noticeable that the rise in the percentage
of dead was greater when cultures were used than when dead lar-
vae were used. This was true in all but one of the experiments,
and it is doubtless due to the fact, determined by microscopical
examination, that the spores were more abundant in the former
suspension. The table also shows the temporary results of the
dipping. As the larvae die and drop off, the percentage of dead
individuals on the leaves rapidly falls until it is about that of the
check.
SUMMARY

I. Natural mortality of whitefly is caused mostly by Micro-
cera (Fusarium) as shown by:
a. The bodies of 98 per cent. of such natural mortality vic-
tims, or pieces thereof, yielded Microcera when grown in suitable
culture media: 28 per cent. being pure colonies of Microcera.
b. No other fungus was obtained even half as frequently.
c. Except in very unfavorable weather, spraying with a sus-
pension of the spores of Microcera caused a marked rise in the
natural mortality. Microcera could always be recovered from
these dead larvae.
d. Spraying or dipping with a suspension of spores from a
pure culture on sweet potato caused fully as marked an effect as
similar sprayings or dippings in a suspension of victims of natural
mortality.
e. The period between spraying or dipping and the appear-
ance of the marked increase in dead larvae corresponds closely
with the time required for Microcera to develop in artificial media.
2. It is possible, by spraying with Microcera, to increase
natural mortality among whitefly, but such increase is only tempo-
rary.
3. Microcera grows best during periods of high humidity
but not too high temperature.
4. It is not as thorough in its work as the brown fungus, or
even the red Aschersonia; that is, it is less virulent.
5. It acts much more quickly than either of the others.
6. It is so universally present in groves that spraying it alone







Annual Report, 1913


into trees is not as important for the grower as it is to spray the
red and especially the brown fungi. Nevertheless, in spraying
either the red or the brown fungus it is an excellent idea to add
Microcera.
7. For spraying purposes artificial cultures of Microcera on
sweet potatoes are to be preferred to the victims of natural mor-
tality, because a much larger number of spores get in suspension
from artificial culture.

WHITEFLY CONDITIONS IN VARIOUS GROVES
STATION GROUNDS.-During August, 1912, the brown fungus
got a good start, and by late October it had pretty well cleaned
up parts of the grove, especially the larger trees. The red Ascher-
sonia was also present and did good execution, but was not as
effective as the brown fungus. In the tent belonging to the De-
partment of Plant Physiology the cinnamon fungus, which was
present the preceding year, obtained such headway by Decem-
ber as to about control the whitefly. From this center of infec-
tion that fungus spread to other portions of the grounds.
So thorough was the work of these fungi, especially the brown
fungus, that the first appearance of adults in the spring of 1913
was light as compared with previous years, in spite of the fact that
the mild winter allowed all the young nursery stock (on which
the fungus does not do as well) to retain its leaves. By the close
of June, the trees were about free from sooty mold.
HAMPTON'S GROVE.-The prophecy made in last year's report
as to the growth of fungus here was more than fulfilled. By
August the brown fungus had the whitefly well in hand. On Sep-
tember 16, the grove was visited. Although the adult whiteflies
were abundant in town about the chinaberry trees, not fifty were
seen in the grove. A collection of ten leaves taken at random
yielded one whitefly pupa, 1693 dead larvae, and 164 empty pupa
cases. Of the dead larvae, 1419 were killed by the brown fungus;
Aschersonia had killed 49; and Microcera, 125. Most of the
empty pupa cases belonged to the preceding (June) brood of
adults, as did probably some of the brown pustules. The fungi
had killed at least 91 per cent. of the adults and probably about
97 per cent. Of 33 new leaves collected, there were eggs or first-
stage larvae on eight. By November the sooty mold had about
disappeared from the leaves and completely so from the fruit,
which was bright and was sold without washing. The leaves are








,Florida Agricultural Experiment Station


still free from sooty mold. On April 19, there were some adults
to be seen in the Satsuma grove; and they were numerous about
some chinaberry trees along the edge of a sink on the south side
of the grove. In the main grove, itself, however, not a dozen were
seen. There was a good bloom, and plenty of fruit was set. How-
ever, the dry weather of April and May prevented the fungus
from making any growth, and by June there was a good distribu-
tion of whitefly over the grove, the younger leaves averaging
about three or four larvae each. The grove had not been fer-
tilized nor well cultivated. The purple scale was very abundant,
and, together with the drought, caused a heavy fall of leaves and
fruit. The brown fungus had gotten a good start.
GRAVES' GROVE.-This grove remained almost free of sooty
mold and whitefly until the September brood. In July there was
a goodly sprinkling of red Aschersonia, but not of the brown fun-
gus. By September the whitefly had emerged to a considerable ex-
tent, and there was some sooty mold. The brown fungus had gotten
a start, and by the latter part of October, when growth largely
ceased, had cleaned up the grove to such an extent that it remained
clean throughout the spring and early summer. The grove was
visited when the June brood was swarming, but little whitefly was
found. The new growth showed a light infestation of adults, but
there was hardly any sooty mold on the old growth. There was a
good setting of fruit on that part of the grove that had not been cut
back.
MONROE AND STEVENS' GROVE (Daytona).-This was visited
on April 5, 1913. There was little whitefly about, and the trees
were nearly clear of sooty mold. The trees were sprayed with
Target Brand in April and July, 1912. Mr. Stevens, however,
stated that the brown and red fungi had done most of the work
of reducing the numbers of the whitefly. The trees that had been
sprayed with Bordeaux mixture during the season of 1911, and
then this not followed up with an insecticide spray, still showed
the effects. The dead wood had been pruned out over the entire
grove, and the trees in question had lost so much wood that they
looked spindling as compared with the others. The whitefly lar-
vae found on Ptelea trifoliata failed to complete their development
on this host.
THE RONNOC GROVES (New Smyrna) were visited on April
4. The whitefly was under better control here than in any
large grove I have visited. There was a good-sized colony di-
rectlv vest of the packing-house in the home erove. Otherwise.







Annual Report, 1913


less than a dozen adults were seen in an hour's inspection of the
groves. About all the trees had been sprayed during May, 1912,
and again in the latter part of July, with Target Brand Insecti-
cide; but nothing had been done since. There were abundant re-
mains of the brown fungus, and it was evidently this that had
nearly completely destroyed the fall brood of whitefly.
THE GROVE OF GEORGE S. SMITH (Lakeland) was visited
on December 11, 1912. There was much fungus, especially both
Aschersonias. Although the grove had not been sprayed with an
insecticide the fruit was free from sooty mold and the trees were
thrifty and bright.
SUMMARY
During the past two years, in the groves under close observa-
tion, the fungi, especially the brown fungus, have done excellent
execution, amounting in most cases to practical control as far as
the summer brood was concerned, and often the fall (September)
brood as well. The brown fungus is'particularly valuable, for two
reasons. In the first place, it spreads over the leaf readily, and,
if not checked by unfavorable weather, will kill every larva there.
In the second place, it works on later in the fall than do the As-
chersonias, thus getting a chance at the fall brood of whitefly.
This excellent work may be due to unusually favorable weather
during the past two autumns, in which case it will be temporary
only, or it may be due to the fact that the fungus is getting so
generally wide-spread and well established over the State. In the
latter event we may hope that this excellent work will be the rule
from now on. Nevertheless, better control is secured if the work
of the fungus is supplemented by one or two thorough sprayings
with some miscible oil. Owing to the fact that April and May
are often dry, the grower should spray some time during these
months. The proper time is two weeks after the bulk of the spring
brood of adults have disappeared. If there is considerable white-
fly in October, after the fungus has about ceased to spread, a
second spraying with insecticide should be given, and also two
weeks after the adults have mostly disappeared. This spraying
will also help to keep down the purple and red scales.

THE WOOLLY WHITEFLY-Aleuriodes howardi
This insect has been spreading rapidly during the past year,
and is now found in groves as far east as Orlando. It was dis-
covered by the Station Entomologist in Arcadia in December, 1912,








lxii Florida Agricultural Experiment Station

and has been sent in also from Winter Haven, Alva, Florence
Villa, Palmetto, Terra Ceia, and from many points in Hillsbor-
ough and Polk Counties. Moreover, in the region which has been
infested for several years, it is increasing in amount. The in-
crease is very variable, however. In and about Tampa, which
was visited on May 15 and 16, the increase has been small. In
the grove of E. W. Aman in Ybor City, there was little or no
increase over the amount present last year. In the grounds of the
Tampa Bay Hotel there was probably an increase of Ioo per cent.
In the R. S. Wilder grove none were found. The writer found
a few infested leaves here last year, which he picked off, apparent-
ly exterminating the colony. In St. Petersburg there was a marked
increase in the amount present. But the heaviest infestation was
found in Lakeland, where the Entomologist was called early in
May to visit the grove of Mr. J. C. Swindell. In the eastern part
of this grove the infestation was very heavy. As one observer
stated, some of the trees looked as if they had been turned upside-
down in a snow-storm. Mr. Swindell was not sure how long A.
howardi had been present in his grove; but in view of the fact
that it had not yet spread to the western side, it cannot have been
long. In the grove of Mr. J. E. Griffin in Lakeland, the infesta-
tion was rather light on May 14; but it had become nearly as
heavy as that in the grove of Mr. Swindell by June II, since
no measures had been taken to combat it.

HONEYDEW AND MOLDS
This species apparently secretes more honeydew than A. citri.
Much of this is caught in the wool, where it collects in shiny drops,
giving the appearance of being covered with snow or hoar frost
to leaves on which there are numerous third-stage larvae or pupae.
If one touches such leaves, he brings down on his head a veritable
shower of honeydew, which is very sticky and disagreeable to
man or beast working in the grove.
The ordinary sooty mold does not seem to develop as abundant-
ly in honeydew secreted by this species as in that secreted by A.
qitri. Other fungi develop abundantly in the honeydew. One is
of a dark yellowish green color. This was pronounced by H.
E. Stevens to be a species of Cladosporium. The other is a Meliola
closely related to the ordinary sooty mold, but with sporangia
nearly globose instead of cylindrical. This species seems to pro-







Annual Report, r913


duce a blacker and thicker layer over the leaf than does the ordi-
nary Meliola.
MEANS OF SPREADING
The adults are distinctly more sluggish than are those of A.
citri. They take wing only when the branch is violently jarred,
nor do they fly as far when disturbed. This sluggish behavior
undoubtedly renders their progress through a grove less rapid,
and makes them even more liable to be carried long distances on
the clothes of people and on vehicles. Adults were noticed cling-
ing to the clothes of a person who had come from an infested
grove, after he had driven two miles. In most cases noticed by
the writer, the first colonies appeared about buildings in a grove,
especially near a barn. In Arcadia the first infestation was in
the yard of the Arcadia House. In the Swindell grove at Lake-
land, it started on the side next to the railroad. These cases show
how readily the insects are transferred on the clothes, of travelers
and on vehicles.
LIFE-HISTORY
Our observations, because of the remoteness of the groves,
have been rather fragmentary. The adults were numerous in both
Lakeland and Tampa on May 14. They had been abundant for
a week, and by May 20 had largely disappeared, although there
were a few on the wing on June I1. Whether this was the first
or second brood of adults this year we do not know. The adults
were common in Tampa last November and December, showing
that there was a late fall brood. Doubtless, there are one or two
broods during the summer.

FOOD
The food preferences of this species for different varieties of
citrus are apparently the reverse of those of A. citri; in that grape-
fruit seems to be its first choice, oranges second, and tangerines
come last. We have found A. howardi on no food plant other
than citrus, although A. E. Back in bulletin 64, part 8, of the
Bureau of Entomology, reports it on mango at Tampa; and W.
S. Tower on guava in Porto Rico. Neither of the last two, how-
ever, seems to be a favorite. At St. Petersburg, guavas in a well-
infested citrus grove were free from it.


Ixiii







Florida Agricultural Experiment Station


PARASITES
The parasite of the woolly whitefly mentioned in the last An-
nual Report was captured at Lakeland and Tampa. They were
abundant in May, crawling about the adult whitefly. As surmised,
this is 'a chalcid, but it has not been identified. A single
specimen of another undetermined chalcid species was caught in
Lakeland. Although, as we mentioned in the last Report, the red
Aschersonia has been found on this species, it does not infect it
readily, and cannot be depended upon for control even during the
rainy season.
SPRAYING
In May a series of experiments was commenced in Mr. J. C.
Swindell's grove in Lakeland. Although rather early to draw any
conclusions, it seems that the early larval stages of this insect will
yield readily to the miscible oil sprays. The third stage larvae
and the pupae are so protected by the collection of honeydew that
sprays seem to have but little effect upon them. Because of their
sluggish habits, a larger percentage of adults are killed by spray-
ing than is the case with A. citri. About fifty per cent. of the
adults were killed by the May spraying.
SUMMARY

I. The woolly, whitefly has spread rapidly, extending as far
east as Orlando.
2. In some groves it is becoming so abundant as to be fully
as serious a pest as A. citri.
3. It is much more resistant to parasitic fungi than is A. citri
or A. nubifera.
4. Two species of chalcids parasitize it, and one of these
is very common.

OBSERVATIONS ON CERTAIN CITRUS INSECTS
Icerya purchase, the cottony cushion scale, which until found
by the entomologist in Tampa in 1911 (see last annual report,
page Iv) had been reported in Florida from the Pinellas Penin-
sula only, has spread rapidly east. The Station has received speci-
mens from Knights, Kathleen, Thonotosassa, Plant City, and River-
view in Hillsboro County; Bartow, Haines City, Lakeland, Chubb,
and Winter Haven, in Polk; Palmetto in Manatee County; and
Crystal River in Citrus County. Some small trees have been re-







Annual Report, 1913


ported as killed in some of the above places. In the groves visited
by the Entomologist the infestation is as yet rather light.
Syrphus fly larvae were observed feeding on russet mites on
the Station grounds at Gainesville. The larvae were not raised
to maturity, hence they are not identified.
Leptothrips floridensis, a new species of thrips, was found in
a greenhouse on the Station grounds. It was found underneath
the loose bark on a small tree whose top had been pruned out.
Heliothrips haemorrhoides, the greenhouse thrips, was observed
infesting orange trees in the greenhouse. The orange does not
seem to have been previously reported as a host of this species.
Pachnaeus opalus. This, an occasional citrus pest, was found
to be quite frequent on magnolia about Gainesville, often feeding
on the opening bud. There has been no observation of its at-
tacking citrus in this vicinity. Perhaps the magnolia is its native
food plant.
Trirhabda brevicollis, was sent in from Emeralda. It was'
damaging grapefruit there, and had wandered on to citrus after
defoliating some prickly-ash trees. It has been a common insect
on prickly ash this year. We have here an additional reason for
cutting out prickly ash from the vicinity of a grove. Its being
a food plant of Aleurodes citri is the other reason. My corre-
spondent stated that the insects were "perfectly controlled by Bor-
deaux mixture."

DESTRUCTIVE INSECTS OF THE YEAR
VELVET BEAN CATERPILLAR
In July of 1912 it became necessary to protect the velvet beans
on the Station grounds against the attacks of the grass-worm,
Laphrygma frugiperda, and later against those of the velvet bean
caterpillar Anticarsia gemmatilis. It is seldom that the former
insect troubles the velvet beans, but the latter is a pest that we
have to contend with every summer. Anticarsia gemmatilis is
heavily parasitized by an entomogenous fungus. In many cases
this fungus about controls it; but at other times, especially dur-
ing dry weather, the Anticarsia nearly destroys the crop. In such
emergencies, one turns naturally to the arsenicals, but velvet beans
are very sensitive to arsenicals. In an attempt to solve the problem
arising from this, considerable attention was given to determining
the maximum dosage that could be used on velvet beans, and its
efficiency in controlling Anticarsia. With lead arsenate there was







Florida Agricultural Experiment Station


burning with a dosage of four ounces of paste and from four to
eight ounces of hydrated lime to fifty gallons of water. However,
in August, the plants could stand a dosage of a half pound of the
paste and one pound of the lime to forty gallons of water, using
eighty gallons per acre, without serious burning, providing there
was a good agitator, and pains were taken to keep the arsenate
from settling. This strength killed the majority of the caterpil-
lars, but by no means all of them. With zinc arsenite powder, we
found that we could use six ounces to forty gallons with six to
twelve ounces of lime, without serious burning, although some
leaves were scorched at half that strength. This strength of dos-
age does not kill all caterpillars. In December we found we could
use over a pound to fifty gallons without material damage. Frost
in December put a stop to the experiments which were resumed
on young seedlings in April. To our surprise we found that at
this time of the year the young plants would stand a dosage as
high as five pounds of lead arsenate paste or two pounds of zinc
arsenite powder to fifty gallons of water without serious burning.
In April some experiments were conducted with a mixture of zinc
arsenite or lead arsenate with lime sulphur, but without very
definite results. These experiments will be continued.


FIG. 7.-Camphor buds infested by Cryptothrips.








Annual Report, p913 xIs i















r
WV .











FIG. 8.-Camphor buds killed by Cryptothrips.
CRYPTOTHRIPS FLORIDENSIS, A NEWLY DISCOVERED PEST OF
CAMPHOR
In November, 1912, there were sent in, by W. O. Richtman of
Satsuma, some camphor leaves infested by an unknown thrips.
These were kept alive in the laboratory. A trip was made to Sat-
suma to observe conditions in the field. This has revealed a type
of injury quite uncommon for a thrips.
In the beginning of the infestation of the camphor tree, the
eggs are laid between the scales of the terminal bud. If the bud
has commenced to develop when the eggs hatch, the larvae attack
the new growth first. If there are but a few of the larvae on
each bud, there will result a blackening and deforming of one

r I


FIG. 9.-Early stage of injury to bark of camphor stem
by Cryptothrips.








lxviii Florida Agricultural Experiment Station





















FIG. Io.-Later stages of injury to camphor
bark by Cryptothrips.

side of the young leaves (Fig. 7). If there are more of the lar-
vae, the developing bud will be killed outright (Fig 8). The
insects then attack the younger twigs, where they feed in groups,
the yellow larvae being conspicuous on the light green shoots of
the camphor. The bark where these groups of larvae feed is
killed (Fig. 9), and, as it dries out, it cracks (Fig. o1). The
adults use these cracks as hiding-places, and as a means of en-
trance to the cambium on which they lay their eggs. As the in-
festation proceeds the bark on all of the twigs is killed, and the
leaves are shed. This leaves the cambium as the only suitable
breeding place, and here the larvae as well as the adults are to be
found. A favorite feeding place is at the base of a branch. This
is quickly killed, and then easily broken off, leaving a scar much
like the base of a petiole, only larger and deeper (Fig. Io). The
insects also gain access to the cambium at the cut ends of the twigs
after the trees have been pruned to supply material for distillation.
The Cryptothrips continue to work on the cambium until the whole
plant is killed. The insect seems to be incapable of flight, although
it has well-developed wings. It probably spreads from one plant
to another by means of workmen and horses which brush against
the plants during cultivation, and by crawling over the ground.







Annual Report, 1913


It spreads in all direction from the center of infestation, but most
readily along the rows where the distance between the plants is
less than that across the rows. It kills every plant in its onward
march, although it may temporarily skip one to attack those be-
yond.
It was also found on large trees at Satsuma, near Palatka,
and at Tampa, but seems to do very little harm to them. It is the
young seedlings in the nursery row and the young trees in the
field that are killed. The writer has been unable to find this in-
sect about Jacksonville or Gainesville or other towns in northern
Florida. This raises the question of its origin. The camphor
is not a native of Florida. Is this insect a native species which
has spread to the camphor, or has it been imported with camphor?
The writer will be very grateful if entomologists located where
the camphor trees grow will send him specimens of a black thrips
(larva yellow) found on this tree.
Tobacco decoctions kill the thrips, but it has been found nec-
essary to make the decoctions stronger than for most species. For
the adults a solution composed of a half gallon of whale-oil soap,
one half gallon of commercial lime sulphur, and a half pound of
Black Leaf No. 40 to fifty gallons of water was necessary. This
has proven quite efficient. It does not, however, kill the eggs,
and of course all the adults and larvae hidden under the bark
escape. By spraying not later than the stage when the larvae are
mostly in the buds or on the outside of the twigs, and by cutting
out all trees in the later stages of infestation, it was found pos-
sible to control this pest.
Laphrygma frugiperda. An account of the first destructive
brood of the fall army-worm or southern grass-worm was given
in the last Annual Report. The next brood of caterpillars appeared
early in July, and was very destructive over the whole of north-
ern Florida, as well as in many other southern States. No com-
plaints were received from south of Marion County. A large
colony on the Station grounds began entering the ground to pu-
pate by July 12, and by July 18 most of the caterpillars had dis-
appeared. At Bonifay, which was visited on July 20, there were
still many caterpillars to be seen, indicating that the brood was
at least a week later there than at Gainesville. The August brood
was not nearly as abundant.
Alabama 'argillacea. A report from Suwannee County that
the cotton-leaf caterpillar had appeared there, caused the ento-







Florida Agricultural Experiment Station


mologist to visit Live Oak on July 25. A two hours' search in the
cotton fields revealed, two pupae. Partly eaten leaves, however,
indicated that there had been many more caterpillars. This early
appearance of the pest led to the fear that the outbreak of 1911
was to be repeated in 1912. However, although the later broods
were somewhat larger about Live Oak and some were taken at
Gainesville and other places, no general destructive infestation
occurred.
Uranotes mellinus on loquat. The cotton square borer was
especially common in'1912 in cotton fields, and the butterfly, the
"gray hair-streak," was very noticeable. Some loquats on which
the bud-worm was working were sent in from Miami. These
caterpillars were raised to maturity, and proved to belong to this
species. I believe that this is the first record of its attacking lo-
quats.
Remigia repanda. In January some caterpillars, taken for the
fall army worm, were sent in from Winter Park, where they had
destroyed a lot of Italian rye-grass. They were raised in the
laboratory, the moths issuing on March 13. This insect, the grass-
looper, is said to be a pest in Porto Rico.
Red spiders were abundant from January to June. In Janu-
ary, the entomologist was called to Starke, where Tetranychus
bimaculatus was severely infesting strawberries. T. mytilaspidis
was abundant on citrus and camphor.
Trichostibas parvula. On December 5, 1912, there were re-
ceived from Seabreeze some caterpillars said to be defoliating
the bay (Persea sp.) The adults were obtained, and the species de-
termined by the Bureau of Entomology. As neither the larva nor
the food-plant of this species had hitherto been known to science,
some pains were taken to determine points in its life-history. The
caterpillars commenced to spin cocoons on December 9. The co-
coon is an open mesh-work affair composed of a few heavy strands
of silk, on the end of a stalk an inch or less long. In about ten
days the adult moths issued from the cocoons, and at once laid
eggs, which had largely hatched by February i. Newly hatched
larvae were again observed on April 13. It is thus seen that dur-
ing the winter months out of doors this insect requires about ten
weeks for a generation. In the laboratory the time was shorter.
In May, when temperature conditions in the laboratory were about
the same as those out of doors, the period was about six weeks.
It would seem that there might be about eight generations in the







Annual Report, 1913


course of a year. The moths, dull black insects about a half inch
long, are very sluggish, and though capable of a short quick flight,
commonly crawl up the trunks of bay trees to lay their eggs. The
larvae, on the other hand, are very active, throwing themselves
about vigorously when handled. They have the army-worm habit
of moving from place to place. When they have stripped a tree,
they let themselves down by means of a silken thread, and crawl
actively over the ground until they reach another tree, which they
ascend. The larvae become restless when full-grown, and descend
to the ground to spin on houses, fences, and trees. Banding the
trees is, therefore, a protective measure, as it protects from both
larvae and adults. Lead arsenate can be used, if one has an out-
fit sufficiently powerful. to throw the spray to the tops of the
trees. When used at a strength of seven or eight pounds per fifty
gallons of water, the leaves were not burnt. The caterpillars be-
came very numerous in February, and again in April. They de-
foliated most of the bay trees, and swarmed over walks and fences
and into the houses. They came down from the trees so abundant-
ly that pedestrians were obliged to carry umbrellas to keep them
off.
Some pupae were found in a grove on an orange tree near
Gainesville. Although no bays were seen near the tree, it is pos-
sible that the caterpillars had merely strayed on to the orange.
They were not seen to attack citrus at Seabreeze.
Hemichionaspis minor was discovered on Asparagus plumo-
sus. This seems to be a new host plant.
Brachytarsus variegatus, noted in the last annual report as
attacking velvet bean seed, is becoming more abundant. It would
seem that we may possibly have here an interesting case of a pest
in the process of development, a native insect slowly acquiring a
taste for an introduced plant.
Respectfully,
J. R. WATSON,
Entomologist.







Florida Agricultural Experiment Station


REPORT OF PLANT PATHOLOGIST
P. H. Rolfs, Director.
SIR: I submit the following report of the work in Plant Pa-
thology for the fiscal year ending June 30, 1913.
The work of the year has been confined to investigations of
citrus and vegetable diseases. Under citrus diseases chief atten-
tion has been given to Melanose, Stem-end Rot, Gummosis, and
Foot Rot. Other diseases have been given such attention as time
and opportunity permitted.
The Assistant Pathologist's time has been occupied mainly
with the investigations of vegetable diseases, principally those
caused by bacteria. His report will be made separately.

MELANOSE
Investigation of this disease has occupied most of the time
during the past year. The cause has been discovered and reported
(Fla. Agr. Exp. Sta. Press Bul. 199), and such measures recom-
mended for control as seemed most practical. The results of the
preliminary work on this disease were reported in the last An-
nual Report (Ann. Rpt. Fla. Sta. for 1912, p. xciii). A press
bulletin (No. 199) was issued on the subject on October 5, 1912.
In December a more detailed report on the disease was published
in Bulletin III, giving the combined results of the independent
investigations of the Plant Physiologist and Pathologist.
Some pruning experiments are under way at present with the
view of controlling the disease by this method, and limiting as
far as possible the use of fungicides and the attendant increase in
scale insects following their use.
From a practical standpoint, the laboratory investigations on
this disease may be considered nearly complete. In the future the
work will be more in the nature of field investigation, and perfect-
ing methods of control and eradication.

CAUSE
Melanose is caused by the fungus Phomopsis citri Fawcett.
The same fungus has been identified as the cause of Stem-end Rot
in citrus fruits by H. S. Fawcett as reported in a previous bul-
letin (Bul. 107, Fla. Agr. Exp. Sta.).
The injury caused by Melanose is confined to young and suc-
culent tissue, chiefly leaves and fruit. The characteristic mark-


lxxii







Annual Report, 1913 lxxiii

ings of the disease are superficial, and seem to be the result of
some toxic action of the fungus rather than the consequence of
vegetative growth within the infected areas. The disease is fully
described and illustrated in Bulletin III.

INFECTION EXPERIMENTS
This phase of the work includes a number of experiments in
which the typical markings characteristic of the disease have been
produced on young orange shoots and fruits. Most of these ex-
periments were carried out in the greenhouse, where moisture
conditions were under control. Young sweet orange trees in pots
were used in these experiments. The trees were two to three
years old, and the tops were cut back occasionally in order to
cause new growth to put out. Growths from four to six weeks
old, or shoots 5 to 7 inches in length, were found to be most sus-
ceptible to infection. Infection rarely occurred on very young
growth, and never on mature or well-hardened tissue.
Dead twigs and branches, collected from citrus trees which
showed heavy Melanose spotting on foliage arnd fruits, were used
as a source of infection. Infection resulted from spraying small
bundles of these dead twigs with sterile water and allowing the
water to trickle over young shoots. Infection was also produced
on young shoots by spraying the same with washings made from
dead twigs in sterile water. A small hand "atomizer" was used
for this purpose. By tying dead twigs to young shoots infection
was readily produced if sufficient moisture was present.
In nearly all cases, potted trees so treated were kept under
bell-jars for twenty-four hours after treatment.
No transfer of infection has yet been effected by using Mel-
anose-infected leaves, watersprouts, or fruits, as a source of infec-
ting material.
Typical Melanose spotting was repeatedly produced on young
foliage by spraying the same with a suspension, in sterile water,
of spores from pure cultures of the fungus.
Tables XVIII and XIX give the results of several series of
experiments in which infection was produced.










TABLE XVIII.
INFECTION RESULTING FROM DRIPPINGS FROM DEAD CITRUS TWIGs, ETC.


Number Source of material
treated

1 shoot Bundle dead twigs -------
1 shoot Infected leaves -----------
1 shoot Infected water-sprouts ---
1 shoot Check ------- ----------
1 shoot Dead twigs ---------


Date
treated

May 10
May 10
May 10
May 10
May 10

May 10
May 10
May 10
May 18
May 18
May 18

May 18
May 18
May 18
May 18
May 18
May 22
May 22
May 22
May 24
May 24
May 29


Infected leaves --------
Infected water-sprout ---
Check ------
Infected grapefruit peel --
Check -----------------
Dead twigs ---------

Check --------------------
Infected leaves --- --
Dead twigs ----------
Dead twigs ------ ---
Check ------
Dead twigs -------- ---
Dead twigs --------
Check-------
Dead twigs ---------
Check -------- -----
Dead twigs -- --- ---


Remarks


Not covered with bell-jar -------
Not covered with bell-jar -------
Not covered with bell-jar .----
Not covered with bell-jar -_----
Covered with bell-jar, 24 hours -


Covered
Covered
Covered
Covered
Covered
Covered


with bell-jar, 24 hours
with bell-jar, 24 hours
with bell-jar, 24 hours
with bell-jar, 24 hours
with bell-jar, 24 hours
with bell-jar, 24 hours


Covered with bell-jar, 24 hours --
Covered with bell-jar, 24 hours -
Covered with bell-jar, 24 hours -
Covered with bell-jar, 24 hours --
Covered with bell-jar, 24 hours --
Covered with bell-jar, 24 hours ..
Covered with bell-jar, 24 hours --
Covered with bell-jar, 24 hours --
Covered with bell-jar, 24 hours --
Covered with bell-jar, 24 hours --
Covered with bell-jar, 24 hours --


Results


No infection.
No infection.
No infection.
No infection.
Slight infection on leaves.
Typical Melanose.
No infection.
No infection.
No infection.
No infection.
No infection.
Slight infection on stem and
leaves.
No infection.
No infection.
Heavy infection.
Good infection.
No infection.
Slight infection.
Very slight, scattered.
No infection.
No infection.
No infection.
Heavy infection.


1 shoot
1 shoot
1 shoot
2 shoots
1 shoot
3 shoots

2 shoots
1 tree --
1 tree --
1 tree --
1 tree --
1 tree --
1 tree --
1. tree --
1 tree --
1 tree --
1 tree --


1















TABLE XIX
INFECTION FROM SPRAYING WASHINGS OF DEAD CITRUS TWIGS


Date
material Remarks infection
appeared

------ Covered with bell-jar ------- ----- June 6
-------- Covered with bell-jar--- ----
------ Covered with bell-jar ------- June 8
------- Covered with bell-jar---- ----- June 15

------- Covered with bell-jar ------- June 24
-------. Covered with bell-jar -------- July 1
----- Covered with bell-jar --- ------ July 9

----- Covered with bell-jar ---------- July 20

-- -- Covered with bell-jar --- ------ August 8


Results


Slight infection, scattered.
No infection.
Scattered infection.
Heavy infection on leaves
and stems.
Good infection.
Heavy infection.
Heavy infection on leaves
and stems.
Good infection, leaves and
stems.
Slight infection, scattered


Date
treated

May 29
May 29
June 4
June 12

June 20
June 27
July 5

July 16

Aug. 3


Number
treated

1 tree --
1 tree --
1 tree -_
1 tree --

1 tree --
1 tree --
1 tree -_

1 tree _

1 tree --


Source of


Washings --
Check --- -
Washings -
Washings -

Washings --
Washings --
Washing --

Washings

Washings


__ ~








Florida Agricultural Experiment Station


INFECTION UNDER FIELD CONDITIONS

Dead twigs from a badly melanosed orange tree were tied to
young succulent shoots of small trees growing in the Novelty
Orchard on May 20. No attempt was made to control the mois-
ture. A dry period of several days followed after the twigs were
tied in. At the end of seven days a heavy rain occurred. Infec-
tion was noted just appearing on the treated shoots four days
after this. Fifty per cent of the treated shoots were infected, as
shown by table XX.
TABLE XX.
INFECTION FROM DEAD ORANGE TWIGS TIED ON SHOOTS


C May 31
D
E May 31
F May 31
G
H May 31
I
J May 31
K May 31
L
M May 31
N May 31


No infection.
No infection.
Slight infection on few leaves.
No infection.
Considerable infection on leaves and stems.
Heavy infection on leaves and stem.
No infection.
Slight infection on stem; heavy infection on leaves.
No infection.
Slight infection on leaves.
No infection.
No infection.
Slight infection, two leaves.
Heavy infection on stem.


This experiment was repeated later in the season, using dead
twigs and small sections of growing water-spouts badly infected
with Melanose, as sources of infecting material. The twigs were
tied to young shoots, under field conditions, just as in the above
experiment, but during a rainy period of several days. A heavy
infection resulted from the dead twigs, but no infection was ob-
tained from the water sprouts. This is shown in table XXI. In
this case infection was noted as just beginning five days after
the twigs were tied in.


Ixxvi








Annual Report, 1913


TABLE XXI.
COMPARISON OF DEAD GRAPEFRUIT TWIGS AND INFECTED WATER SPROUTS.




0o Q
o Remarks

o CO


ADead twig -------- une 5 June 10 Heavy infection on leaves and stem.
B Dead twig ---------June 5 June 10 Heavy infection on all leaves.
C Dead twig -June 5 June 10 Liberal spotting, confined to stem.
D Dead twig ---------- une 5 June 10 Slight infection, scattered.
E Dead twig ----- une 5 June 10 Heavy infection on leaves and stem.
F Dead twig ------ June 5 June 10 Heavy infection on leaves.


G Water sprout --------June 5 1------- No infection.
H Water sprout --------June 5 -------- No infection.
I Water sprout-------- June 5 -------No infection.
J Water sprout------ --June 5 ------ No infection.
K Water sprout------ June 5---- No infection.
L Water sprout ------- June 5 ------No infection.


FILTERED AND UNFILTERED WASHINGS

The object of this experiment was to determnie if the infection
resulting from the use of dead citrus twigs as a source of infect-
ing material was due to some soluble toxin in the dead wood, or
whether it was due to the presence of some organism. Washings,
in sterile water, were made from a quantity of dead twigs selected
from citrus trees the foliage and fruits of which were badly af-
fected with Melanose.
A part of the washing was filtered through a Berkefeld filter.
A second part was filtered through two or three layers of coarse
filter paper. A third part was not filtered. Agar plate cultures
were made from each of the three. Each was also sprayed on
young sweet orange shoots, and the treated trees were covered
with bell-jars for 24 hours.
The results of this experiment (as indicated in table XXII)
may be summarized as follows:
(i) Unfiltered washings (containing spores of several species
of fungi and bacteria) produced decided lesions on young foliage
in each case.
(2) Part of the same washings when filtered and free from


lxxvii








Ixxviii Florida Agricultural Experiment Station

fungus spores and bacteria (as shown, by culture plates) pro-
duced no lesions on young foliage.
(3) Part of the same washings, when filtered so that only a
part of the fungus spores were removed, produced only a few
scattered lesions on the foliage.
(4) The lesions did not then result from any soluble toxin
in the dead twigs; but were due to some organism, and probably
to a fungus species.








TABLE XXII.
COMPARISON OF FILTERED AND UNFILTERED WASHINGS


Washings


Unfiltered _-----------_-

Filtered through Berkefeld filter

Unfiltered ----- -----
Filtered through filter paper --

Filtered through Berkefeld filter
Unfiltered --------------
Filtered through filter paper --


Filtered through Berkefeld filter
Unfiltered ---- __-----

Filtered through filter paper _


Results on orange shoots


Scattered infection on leaves ------

No infection---------------------

Heavy infection on leaves -------
No infection-----------------

No infection-- ------------
Liberal infection on leaves and stems
Few scattered spots on two leaves.
Very slight infection -

No infection---
Heavy infection on leaves and stems

Very slight infection, few scattered
spots ----.. -------------------


June 4

June 4

June 12
June 12

June 12
June 20
June 20


June 20
June 27

June 27



June 27


U,
c"
~dMr
b"U)
C5


4-6 1S !-
6(3dt
_--P4-


Results of plate cultures
of washings or filtrates.


Numerous fungi and bact ri-
al colonies.
No fungus or bacterial
growth.
Fungi and bacteria numerous
Numerous bacterial colonies
of several species.
.qo growth.
Fungi and bacteria.

Numerous bacterial colonies,
and some fungi.
No growth.
Numerous fungi and bacteri-
al colonies.

Numerous bacterial colonies,
several species. Few colo-
nies of fungi.
\o growth..


Filtered through Berkefeld filter No infection ---------------------











TABLE XXIII.
INFECTION FROM PURE CULTURES
Suspension of spores in sterile water. Sprayed on foliage with atomizer, and trees covered with bell-jars for twenty-four hours.


Date Number
treated treated

1912
July 23 1 tree
July 31 1 tree
Aug. 5 1 tree
Aug. 5 1 tree
Aug. 12 2 trees
Sept.13 1 tree
Sept.13 1 tree
Sept.18 1 tree
Sept.18 1 tree
Sept.21 1 tree
Sept.21 1 tree
Oct. 2 1 tree
Oct. 2 1 tree
Oct. 3 1 tree
Oct. 14 1 tree
Oct. 28 1 tree
1913
Jan. 8 1 tree
Jan. 9 1 tree
Jan. 15 1 tree


Age of
culture


1 year ---.
3% months
4 months_-
1 year-----
2 months--
1 month_--
1 month -_
1 month--_
1 month--_
1 month --
1 month---
2 months-_
6 weeks ---
5 weeks ---
7 weeks --
5 weeks --_

7 months--
1 month-__
2 months--


SDate
Culture medium infection
appeared


Sterile orange wood -_
Sterile orange sticks _
Sterile orange sticks __
Sterile orange sticks
Sterile orange sticks
Sterile orange sticks _
Sterile bean stems --
Sterile cowpea stems -_
Sterile orange sticks --
Sterile orange sticks -_
Sterile orange sticks --
Sterile orange sticks -
Sterile orange sticks _
Sterile orange sticks -
Sterile orange sticks _
Sterile orange sticks _

Sterile orange sticks -
Sterile bean pods ---.
Sterile bean pods ----


Aug. 5
Aug. 12

Aug. 16
Sept. 17
Sept. 17
Sept. 21

Sept. 24
Sept. 24
Oct. 11
Oct. 7
Oct. 7
Oct. 19
Nov. 1

Jan. 13
Jan. 13
Jan. 18


Remarks


No infection.
Slight infection, scattered.
Very slight infection.
No infection.
Good infection on leaves and stem.
Good infection.
Liberal infection on.all leaves.
Heavy infection.
No infection.
One shoot treated. Good infection on all leaves.
Slight infection, scattered..
Scant infection.
Heavy infection on leaves and twigs.
Heavy infection on few leaves.
Heavy infection on leaves and stems.
Scant infection, scattered.

Very heavy infection on leaves.
Good infection.
Good infection on all leaves.







Annual Report, 1913


EFFECT OF FUNGICIDES IN PREVENTING MELANOSE INFECTION
Some preliminary experiments were carried out in the green-
house, on orange trees in pots, to determine the effectiveness of
lime-sulphur, Bordeaux mixture, and ammoniacal solution of cop-
per carbonate in preventing Melanose infection.
Foliage was. selected when in the most susceptible -stage for
infection, care being taken to choose shoots as nearly as possible
of the same age and degree of succulence. The foliage was sprayed
with the fungicide solution 24 hours before applying the spores.
The upper and lower surfaces of the leaves were thoroughly
covered with the fungicide, and allowed to dry. Spores from
pure cultures of the fungus in sterile water were used as infecting
material.
After the foliage was thoroughly sprayed with the suspension
of spores, the trees were covered with bell-jars for twenty-four
hours.
Checks were only treated with a suspension of the spores; and
served as a basis for comparing the amount of infection in each
experiment.
The lime-sulphur used was one of the commercial brands, and
was diluted with water to I part in 30. It seemed to completely
prevent infection, but caused more or less injury to the foliage
by burning or scalding the edges of the leaves, or by producing
yellowish blotches or spots on the surface. On many of the leaves
small spots were noted. These were not typical of Melanose
injury but resembled more nearly the injury produced by Cladospo-
rium citri.
The Bordeaux mixture was prepared in the laboratory, and was
used in the strength of 5-5-50. While this solution did not entirely
prevent infection, the amount of spotting per leaf in most cases was
so small and scattered that it can well be considered negligible. No
injury to the foliage resulted from the use of Bordeaux mixture.
The ammoniacal solution of copper carbonate was prepared in
the laboratory according to the following formula:
Copper carbonate -------------------------- 5 ounces
Ammonia (26 Baume) --------------------------- 3 pints
Water --------------------------------------- 50 gallons
This solution did not entirely prevent infection, but the amount
produced was so small that it may be considered negligible. In most
.cases, Bordeaux and ammoniacal solution of copper exhibited about
the same degree of control. In one of the experiments a slight


lxxxi








lxxxii Florida Agricultural Experiment Station

burning of the foliage resulted from the use of the ammoniacal
solution of copper.
The results of the experiments are given in table XXIV.

LESIONS PRODUCED ON GROWING FRUITS
Lesions were produced on growing Kumquat (Citrus japonica)
fruits under field conditions by tying small twigs to clusters of
the fruit, on July 18. No attempt was made to control the moist-
ure conditions, and infection did not result for nearly a month
after the fruits were treated. The results are given in table XXV.







TABLE XXIV.
COMPARISON OF FUNGICIDES


No. of
leaves
treated


113 Bordeaux --------


Date


Mar. 20

Mar. 20
Mar. 20

Apr. 9
Apr. 9

Apr. 9


Remarks


Fungicide

Checks ---

Lime-sulphur ----
Bordeaux ---

Checks --------
Ammon. sol. ----

Lime-sulphur --__


Checks --- ----

Bordeaux .....-_-

Lime-sulphur --.

Checks __ ---
Ammon. sol. --__

Lime-sulphur ----
Checks .--- ----
Ammon. sol. _--_


No.of
leaves
infected

62

0
38

28
26

0


67

55

0

21
0

0
86
41


Heavy infection on leaves and stems, varying from few spots
to two or three hundred per leaf.
No infection.
Scattered infection. Few spots per leaf. Few leaves rather
heavily spotted, but not so much as checks.
Heavy infection on few leaves. On others scattered.
Slight infection. Few scattering spots on leaves. Negligible as
compared with checks.
No typical infection. Slight spotting on few leaves. Apparently
spray injury. Edges of several leaves burned. Considerable
injury to foliage.
Good infection, very heavy on some of the leaves. Others
slightly spotted.
Very slight infection. Scattered spots. Almost negligible
in comparison with checks.
No infection. Few leaves spotted by spray injury. Some spray
burning on edges of several leaves.
Very slight infection in general. Scattered.
No infection. Decided spotting and injury to foliage by fungi-
cide.
No infection. Foliage burned and badly injured by fungicide.
Heavy infection on leaves and stems. The greater number of
leaves liberally spotted.
Very scant infection, scattered. Negligible in comparison with
checks.
Scant infection, scattered. Slightly more than on leaves treated
with ammon. sol.


Apr.

Apr.

Apr.

May
May

May
June
June


June 2












TABLE XXV.
INFECTION OF KUMQUATS


Source of infection


Dead twigs __---
Dead twigs __---
Dead twigs -----
Check ---------
Dead twigs -----
Dead twigs -----
Dead twigs -----
Check ----------
Dead twigs -----
Dead twigs -----
Check ----------
Dead twigs -----
Dead twigs -----
Dead twigs ---
Check ----------
Dead twigs -----

Dead twigs -----
Dead twigs -- --
Check ----------


No. dropped INo. infected


6
12
2
6
3'
----------
9
3
2
1
6
0
0
0
2
1

0
1
0


5
1
1
0
1
2
1
0
3
6
0
4
5
4

2

0
1
0


Appearance Remarks
of infection

Aug. 12 Heavy infection on all fruits.
Aug. 12 Very heavy infection.
Aug. 12 Slight infection.
No infection.
Aug. 12 Slight infection.
Aug. 12 Slight infection.
Aug. 12 Slight infection on 1 fruit. Three not infected.
No infection.
Aug. 12 Slight infection. Also injured by rust mites.
Aug. 12 Heavy infection.
No infection.
Aug. 18 Liberal infection.
Aug. 18 Heavy infection.
Aug. 18 Slight infection.


Aug. 12


JTwo fruits slightly infected.
Two not infected..
No infection.
Slight infection.
No infection.


No. of fruit
in cluster
treated


I 1-----f-----


----








Annual Report, 1913


PRUNING EXPERIMENTS
An experiment in pruning to control Melanose was begun dur-
ing the month of January. Fifty-six trees were selected, in a
grove which had been badly affected with Melanose the past sea-
son. The dead wood had not been removed from the trees in
this grove for two seasons, and the conditions were ideal from
the standpoint of the experiment. The fifty-six trees were divided
into blocks of twelve and of sixteen. One block of twelve trees
was not pruned, but left as a check. A second block of sixteen
trees was pruned in January and June, care being taken to re-
move all visible dead wood at the time of pruning. A third block
of sixteen trees was given a thorough pruning in January. In
June a fourth block of twelve trees was pruned.
The pruning in each case required considerable time and care,
and the smallest dead twigs were cut out as far as possible. All
prunings were removed from the grove and burned, immediately
after the work was finished.
The results of this work will be reported at a later date, as
sufficient time has not elapsed to give definite data from which
to draw conclusions.
STEM-END ROT

Very few cases of Stem-end Rot were reported during the
past season, and the disease was apparently' inactive. This, in a
measure, prevented the carrying out of certain field experiments
for control, and a study of the conditions under which the disease
occurs in the groves. Investigations were confined chiefly to estab-
lishing the relationship between this disease and Melanose.

GUMMOSIS
This disease has been more or less active the past two or three
years and is apparently increasing in extent. The work on this
disease the past year has been of a preliminary nature, and con-
fined to field observations, infection experiments, and experiments
for control. Thus far the investigations have not progressed far
enough to justify a report.

FRUIT ROTS
An unusual amount of rot in fruits was reported the past sea-
son from a number of localities in the State. Reports from sev-


1xxxv








Florida Agricultural Experiment Station


eral such localities estimated the loss in fruit from 5 to 50 per
cent. While the trouble was mainly due to the presence of the
Blue Mold fungi (Penicillium italicum and P. olivaceum), other
factors contributed largely to swell the percentage of loss. A
severe splitting of fruits occurred in many groves during the early
part of the season. This was followed by warm, humid weather
which afforded ideal conditions for the rapid development and
spread of the fungus. Fruit from such groves, unless very care-
fully handled in picking and packing, developed a large percentage
of decay in shipment. Groves in which no splitting occurred and
where very little Penicillium had developed, showed little or no
decay in fruit.
SCAB
(Cladosporium citri Massee)
This disease is becoming more troublesome, and is causing
considerable injury to grapefruit. Many groves in the southern
part of the State suffered severely the past season from the attacks
of this fungus.
VEGETABLE DISEASES.-The work on vegetable diseases is given
in the following Report of the Assistant Plant Pathologist.
Respectfully,
H. E. STEVENS,
Plant Pathologist.


Ixxxvi







Annual Report, 1913


REPORT OF ASSISTANT PLANT PATHOLOGIST
LETTUCE DISEASES
BACTERIAL ROT

Bacterial rot of lettuce (Fla. Agr. Exp. Sta. Report for 1911),
did little damage last year. This may be due. to the dry weather
which prevailed in the fall. Many seed-beds were examined, but
no signs of the disease were found. Nevertheless later in the
growing season it did make its appearance at a few places. One
lettuce field near Gainesville became affected with bacterial rot.
The infected field lay in a depression, and was surrounded on
three sides by timber land. The field was rather damp, and the
protection which the timber offered kept the cold winds from injur-
ing it.
The field was visited on December 12, 1912. Specimens were
taken to the laboratory and the causative organism, was isolated.
Another visit was made the following day, and search was made
for some insect that might be a factor in spreading the disease.
An examination of many plants showed the presence of reddish-
brown aphids in large numbers. The aphids were collected in
small vials and brought home and placed on healthy lettuce
plants. After the aphids were placed on the plants each plant was
wrapped with paraffined paper to keep the aphids from traveling
to the other plants.
In five days after the aphids were placed on the healthy let-
tuce plants, the disease was noticed on these plants; while the
check plants were free from the disease.
On December 19, aphids were again collected from the infected
field and placed on two healthy lettuce plants. The plants were
wrapped with paraffined paper as in the previous experiment. Two
plants were wrapped in the same manner, but no aphids were
placed on them. In six days the infested, plants showed that they
had become inoculated; while the check plants showed no signs
of infection. On January 2, the infected plants were reduced to
a black, putrid mass. Upon examining the check plants it was
found that slight signs of the disease had made their appearance.
But a thorough examination also revealed the presence of some
aphids which had presumably escaped from the infested plants.
Certain diseases have been proved to be carried by aphids.
H. A. Allard, in Science, N. S. Vol. 36, pp. 875-77, states that
the mosaic disease of tobacco is carried by aphids. An aphid is


lxxxvii







Ixxxviii Florida Agricultural Experiment Station


a factor in the spread of pear blight (Jones, D. H., Ont. Agr.
Coll. Bull. 176, pp. 1-63. Stewart, V. B.: Bul. 329. Cornell Agr.
Exp. Sta., p. 341.)
LETTUCE DROP
Lettuce Drop, due to Sclerotinia libertiana, did much damage to
the crop in the past season. The trouble was worse on old land.
Two fields were kept under observation which belonged to one
grower. One of the fields had been planted in lettuce for four
years, the adjoining field had been planted for three years. The
field that had been planted for four years had very much more
Drop than the field which had been planted only three years. The
grower said the Drop was getting worse every year.
The fungus was isolated from diseased material, and trans-
ferred cultures made on sterilized green beans, regular agar, and
cracked corn. There was a good growth of mycelium on these
media. In fourteen days after inoculation all the tubes had de-
veloped sclerotia. The hyphae also put out branches, which when
they came in contact with the walls of the tube began to branch
and formed appressoria. These finally were round and black,
ranging from 2 to 5 mm. in diameter.
A culture on regular agar plates was made from a apothecum
on February 6. On February 7 the spores began to germinate.
On February 14 sclerotia were formed on the agar in each plate.
On the top of each sclerotium there appeared a drop of a light
amber-colored liquid.
In December I made transfers from pure cultures on cracked
corn, and sclerotia were found in a few days. In January the
sclerotia began to put out horn-like processes, as if they were
going to form apothecia. But by February these horns were dried
and new ones were being put out. In no case did apothecia form,
only the horn-like processes which varied from 3 to 10 mm. in
length. Sclerotia were gathered at different times during the
year, with the view of finding out what factors controlled the
production of apothecia. Some of the sclerotia were placed in
boxes filled with potting soil, and put in the open. Some of the
other sclerotia were put in test-tubes which contained sterilized
potting soil. Some of the tubes were kept in the ice-chest, while
others were kept at room temperature.
On March 25, 1912, sclerotia were gathered and put in a
box as stated above. On November 22, 1912, the first apothecium
was found, and I kept on finding apothecia until March 20, 1913-








Annual Report, 1913


I found most apothecia on January I, namely 30; they ranged
from I 1-4 to 7 mm. in diameter. In a second box on December
18, 1912, I planted sclerotia which had been gathered from dis-
eased plants on the same day. On January 25, 1913, these sclero-
tia began to produce apothecia.
In a third box on February 20, 1913, were planted sclerotia
which had been gathered the same day from diseased plants. On
March 27, apothecia began to appear in this box, and they con-
tinued to be formed until April 19, 1913. Since that date apo-
thecia have not been found in any of the boxes. It seems that
temperature and moisture have some effect on the production of
apothecia. Below is given a table of the average maximum and
minimum temperatures for seven months.
Maximum. Minimum.
F. F.
October ---------------------------- 80.8 64.2
November---------------------------- 71.7 46.4
December ---------------------------- 70.4 53.7
January ------------------- 75.0 55.5
February ------------------------------ 66.3 45.6
March ------------------------------- 75.4 57.9
April ---------------------------- 79.8 55.5

Complaints were received from the lettuce-growing district that
the drop commenced in the fields about the latter part of Novem-
ber. Stevens, in Bul. 217, N. C. Agr. Exp. Sta., says: "The
sclerotium germinates under suitable conditions usually after a
lapse of several months to nearly a year under field conditions."
But we have found that under field conditions in Florida sclerotia
may form apothecia in about a month's time.
In the other experiment the sclerotia were gathered and put
in test-tubes, which were partly filled with sterilized soil; some of
the tubes were kept at room temperature and the others in the
ice-chest. Table XXVI shows when the sclerotia were put in
the tubes and when they began to germinate. As stated above,
no true apothecia were formed, sterile horn-like processes only.
At the room temperature only a mycelial growth was produced.


lxxxix








Florida Agricultural Experiment Station


TABLE XXVI
Date of placing Date of produc-
sclerotia in ing apothecia at
tubes, temperature in
ice chest.
March 1913 ----------------------------------------------March 28,
horns produced.
March 0o, 1913 ------------------------------------------------April 9,
horns produced.
March 28, 1913 ---------------------- -------------- Cultures neglect-
ed until June 5,
horns produced.
April 12, 1913 ---------------------------------------------- June 5,
horns produced
April 29, 1913 -----------------------------------------------June 5,
horns produced.
May 22, 1913 ----------------------------------------------- June 24,
horns produced.

The sclerotia which were used in the above experiment had
been standing in an open dish at room temperature since they
were taken from the lettuce plants on February 25, 1913. The
temperature of the ice-chest varied between II and 18 degrees C.
The above table shows that for the germination of the scle-
rotia of Sclerotinia libertiana temperature plays an important part.
Infection experiments were tried by placing bits of mycelium
on plants, and by placing spores in healthy and injured plants.
On February 12, 1913, small pieces of apothecia were dropped
on healthy lettuce plants; no infection occurred. On February
20, 1913, pieces of apothecia were placed at the bases of leaves
of 5 plants, where a cut had been made with a sterile scalpel. In
30 days one plant was entirely decayed, and three were badly af-
fected, while one plant remained healthy.
On February 20, 1913, pieces of apothecia were placed at the
ground line of 5 healthy plants. In a month's time all the plants
were affected.
On February 12, sixteen healthy plants were inoculated, by
placing some mycelium of a pure culture in each plant. On Feb-
ruary 24, fifteen of the plants were affected with the disease.
Stevens, Bul. 217, N. C. Agr. Exp. Sta., and Stevens and Hall,
"Diseases of Economic Plants," p. 243, say that this fungus must
first pass a saprophytic life before it becomes a parasite. De Bary
in Bot. Zeit, 1886, Nos. 22-27, expresses the same view.

BACTERIAL ROT OF CUCUMBERS
Work on the cucumber rot was carried on this year. The
damage done was not as great as that of last year. This may be







Annual Report, 1913


FIG. II,-Cucumber leaf affected with bacterial rot.


accounted for by the absence of heavy rain. However, the early
cucumbers were damaged considerably Vy the cold and wind.
Toward the end of the cucumber season the Blight (Pseudoper-
onospora cubensis)- did considerable damage. Thus the crop was
cut short; but on account of high prices the grower did not ex-
perience any financial loss.
The bacterial disease of cucumbers, described in Rept. of Fla.
Agr. Exp. Sta. for 1912, and in Phytopathology. Vol. 3, makes
its first appearance on the leaves. The leaves become yellow-
spotted, these spots becoming confluent, and finally the tissue be-
comes hard and dry and then falls away. (Fig. I1)
SThe cucumber fruit becomes infected in all stages. The growers
made complaints that the fruit was not setting. On examining
the vines, many small cucumbers were found which were dried
and shrunken. (Fig. 12.) In the larger cucumbers the infection
makes its appearance as small watery spots, which turn white, and
are from I to 3 mm. in diameter. Underneath these spots will
be found soft brown areas where the tissue has been disorganized
by the action of the bacteria.







Florida Agricultural Experiment Station


FIG. I2.--Young cucumbers affected with bacterial rot.

The bacteria make their way through the tissue of the cucum-
ber by working in the intercellular spaces and dissolving the mid-
dle lamellae. This is done first by the cell walls beginning to
swell, then the middle lamella is dissolved, separating the cells
from their neighbors. This same action has been noticed by Jones
(Vt. Agr. Exp. Sta., Bul. 147) in regard to soft rot.
The organism was isolated from the diseased areas, and fur-
ther work proved it to be a bacillus. The bacillus was grown
in different media, following closely the chart adopted by the
Society of American Pathologists.
The bacterium grown on standard agar at 30 degrees C. and
stained with gentian violet, showed as short rods I12 to 2 microns
long and I micron wide, the majority being 2 microns long.
Stained by Hugh Williams' method they showed peritrichiate fla-
gella. Ribbets' method showed the presence of a capsule. The
bacteria are not stained by Gram's method. Spores have not
been found.
Stroke cultures on regular beef agar are scanty, filiform, flat,
glistening, verrucose, opalescent, and slimy. In agar stab cultures
and in gelatin stab cultures, growth is best at top, and villous in
line of puncture. Gelatin is not liquified. A membrane is formed
on nutrient broth, with strong cloudiness, and compact sediment.
Milk coagulates slowly, extrusion of the whey beginning in seven
days. Agar colonies are round to ameboid, smooth, convex and
amorphous. There was no gas formed in fermentation tubes, but
growth occurred in the closed arm. To test-tubes containing Io
cc. of milk, I cc. of methylene blue was added: these were bleached
in four days by the organism. In beef bouillon with 2 per cent.
of glycerine or 2 per cent. of saccharose, there is fluorescence. No







Annual Report, Ip13 xciii

indol is produced. Nitrates were not induced. Starch was di-
gested.
Inoculations were made to find out whether the disease was
communicable.
Diseased leaves were taken and pinned to healthy leaves, then
wrapped in paraffined paper. In every case the healthy leaves
became affected.
An affected cucumber was taken, and with a sterile scalpel a
piece of the diseased tissue was removed. A healthy cucumber
still hanging on the vines was washed with 95 per cent. alcohol.
An incision was made in the fruit with a sterilized scalpel, and
the piece of diseased tissue inserted in the wound. The cucumber
was then wrapped with paraffined paper. Typical rot was induced
in this cucumber.
Pure cultures were isolated by the agar-plate method. The
organism was transferred to a tube of beef bouillon. After 24
hours the culture was brushed on healthy leaves, and the character-
istic disease appeared. A similar culture was brushed on a cu-
cumber, and the cucumber was wrapped with paraffined paper.
The typical spots were produced. Flowers were inoculated in the
same manner by putting the culture on the stigma. The young
ovaries turned yellow and withered.



"* Y : '



I ;,Wk
r'~"* I"'l'r CI:i M


FIG. I3.-Inoculation of old cucumber after wounding with needle.
(Check on right.)







Florida Agricultural Experiment Station


Agar-streak cultures were placed on uninjured cucumbers: and
in seven to ten days the characteristic spotting made its appear-
ance. If the cucumbers were pricked with a sterile needle, and
the culture placed on the wound, the cucumber began to form gum
in two to three days.( Fig 13).
During this past season fifty inoculations were made, and
forty-two infections occurred. There were twenty checks, and
none of these checks were affected.
Control experiments were next begun in the field, in co-opera-
tion with a grower at Williston, Fla. Four sprayings were made
with Bordeaux mixture of 4-6-50 strength. At the close of the
picking season, the sprayed vines were the healthiest, and did not
bear as much infected fruit as the unsprayed vines. As this was
only a preliminary experiment, more work must be done to estab-
lish this point. But this experiment seemed to lead to the con-
clusion that Bordeaux mixture would control this bacterial disease.
N. J. Giddings, in Bul. 148, of Vt. Agr. Exp. Sta., states that
Bordeaux mixture would control the soft rot of muskmelon caused
by Bacillus-melonis Giddings.

TOMATO DISEASES
The bacterial and fungus wilt of tomatoes have done consid-
erable damage this year.
Along the East Coast complaint was received in regard to
Alternaria spotting of fruit, which caused considerable damage.
Complaints were also received concerning the End-Rot of
tomatoes. Specimens were received from different places in the
State, and the following organisms were isolated. A bacterium
which gave a yellow growth on agar, an Alternaria, a Fusarium
and Sclerotium rolfsii. Inoculations were made on healthy green
tomatoes. A rotting, resembling the End Rot as it appears in
the field, was induced by the Fusarium and by Sclerotium rolfsii.
Many of the specimens of End Rot gathered by the writer came
from plants affected with the Fusarium wilt or the wilt due to
Sclerotium rolfsii.
The potato crop in the State was again attacked by a severe
epidemic of Phytophthora infestans. In some places the crop was
cut down to one third of what was usual in other years. In the
Hastings section many of the growers have sprayed with Bor-
deaux mixture, and report remarkable success.


xciv







Annual Report, 1913


BEET DISEASE
The beet crop was attacked by the leaf spot, caused by the
fungus Cercospora beticola. Root-knot was a common complaint
this season.

CELERY DISEASES
The celery districts were visited again with "heart rot" and
"foot rot" of celery. Heart-rot is caused by a bacterium, and
foot rot is caused by Sclerotinia liberliana.

ONION DISEASES
The onions were affected with a dying down of the tops. The
leaves would first become white-spotted, then these spots would
turn brown, and finally the whole leaf would be involved.
It was found that thrips were injuring the leaves and then a
Macrosporium appeared in the wound.
From one community specimens were sent in which were af-
fected with Peronospora schleideni.

CANTALOUPE DISEASES
Cantaloupes were affected this year with the blight caused by
Pseudoperonospora cubensis. The damage done by this disease
has been considerable.
A peculiar disease was noted in cantaloupe fields which blighted
the terminals of the vines. On examining the young buds abun-
dant Alternaria spores were found, The disease stunts the vines,
which become nearly useless, bearing none, or perhaps only one
or two melons during the season. The trouble seems to be rather
new about here, the old growers stating that last year was the
first time it had been noticed.
Respectfully,
O. F. BURGER,
Assistant Plant Pathologist.


xcv








xcvi Florida Agricultural Experiment Station

REPORT OF CHEMIST
P. H. Rolfs, Director,
SIR: I submit herewith the report of the work in chemistry
for the year ending June 30, 1913.

CITRUS EXPERIMENTAL GROVE
CONDITION AND TREATMENT.-References to the dieback ex-
isting in the grove have been made in previous reports, and also
the treatment followed to effect a cure. Observations made in
June of this year indicate that the trees are nearly out of the
dieback condition, and have made a fairly good growth this year.
Lack of nitrogen was indicated quite generally over the grove.
Cultivation has been continued, following the plan originally
adopted. A good stand of beggarweed was noted over nearly
all the grove. This is cut once or twice for hay during the season.
Following the plan adopted last year, no fertilizer was applied
until June of this year, when the usual application of two pounds
was given to each tree.
MEASUREMENT OF TREES.-In Table XXVII is shown the in-
crease in growth of the trunks of the trees from June, 1909, to
June, 1913, together with the fertilizer treatment which each
plot receives.
The clean-culture plots, 47 and 46, continue to show the largest
gains. Plot 43, which receives no fertilizer, has continued to drop
in the list, and is now in the twentieth place.
The smallness of the gains noted in the last twelve plots in
the table is due either to the excessive amounts of fertilizer added
above the standard, or to the fact that dieback was more severe
in these plots. So far, the factors which stand out as evidently
influencing growth are, clean culture and excessive fertilization;
the former in increasing and the latter in retarding growth. With
the other plots, the data are not conclusive. No fertilizer or com-
bination of fertilizers shows a predominating influence on growth.
Below is given the average diameter of the 480 trees of the
grove for each year since being set out.
1909-22.52 thirty-seconds of an inch.
1910-26.90 thirty-seconds of an inch.
1911-36.57 thirty-seconds of an inch.
1912-46.72 thirty-seconds of an inch.
1913-56.66 thirty-seconds of an inch.








Annual Report, 1913 xcvii

TABLE XXVII.
AVERAGE GAIN IN DIAMETER OF TREES, FROM JUNE, 1909, TO JUNE, 1913




o 0 5 Fertilizer Treatment.
.z "-



47 45.3 Nitrogen from dried blood. Clean culture.
46 44.9 Standard. Clean culture.
36 44.7 Phosphoric acid from floats. (4 times amt.) Cot. seed meal.
37 43.5 Potash from low-grade sulphate.
13 42.8 Standard. Mulched.
41 42.7 Standard.
48 42.1 Nitrogen from nitrate of soda. Clean culture.
12 41.6 Standard and air-slaked lime.
22 41.6 Half nitrogen, cotton-seed meal; half, sulphate ammonia
2 40.3 Standard.
35 39.6 Phosphoric acid from floats. (4 times amt.)
30 38.7 Acid phosphate, nitrate of soda, hardwood ashes.
31 38.3 Standard.
45 37.6 Standard. Mulched.
38 37.5 Potash from muriate.
44 37.5 Standard.
34 37.4 Phosphoric acid from floats. (Twice amt.)
8 36.7 Phosphoric acid and potash decreased by one-half.
26 36.7 Phosphoric acid from steamed bone. (Twice amt.)
43 36.6 No fertilizer.
21 36.5 Nitrogen from cotton-seed meal. Ground limestone.
29 36.4 7%/2 potash in June, 71/ in Oct., 3 in February.
25 35.6 Phosphoric acid from steamed bone.
23 35.2 Nitrogen, % cotton-seed meal, 1/ nitrate soda.
42 34.6 Potash from nitrate of potash. Balance nitrogen, nitrate
soda.
20 34.5 Nitrogen from cotton-seed meal.
32 34.4 Phosphoric acid from dissolved bone-black.
6 32.6 Phosphoric acid and potash increased by one-half.
28 32.4 Phosphoric acid from slag (twice amt.) Nitrate of soda.
1 32.3 One-half standard.
33 32.3 Phosphoric acid from floats.
9 32.2 Phosphoric acid and nitrogen decreased by one-half.
11 31.7 Standard and ground limestone.
39 31.0 Standard and ground limestone.
24 30.7 Phosphoric acid from dissolved bone-black.
19 30.2 Nitrogen, % nitrate of soda, 1/2 dried blood.
7 30.0 Nitrogen and potash increased by one-half.
3 29.8 Twice standard.
10 29.3 Nitrogen and potash decreased by one-half.
15 29.3 Nitrogen from nitrate of soda.
18 28.0 Nitrogen, %/ sulphate ammonia, 1/ dried blood.
Si 25.5 Standard.
27 '25.4 Phosphoric acid from slag. Nitrate of soda.
40 24.1 Potash from kainit.
16 24.0 Nitrogen, % nitrate of soda, 1/ sulphate of ammonia.
5 21.0 Phosphoric acid and nitrogen increased by one-half.
17 20.7 Nitrogen from dried blood.
4 15.1 Four times standard.







Florida Agricultural Experiment Station


SOIL TANK EXPERIMENT

This work has continued along the lines discussed in previous
reports. There are now two batteries of four tanks each in opera-
tion. The trees in the first battery were severely attacked by
scale and whitefly during the past year, and were sprayed in March
with an insecticide for these insects. The trees in tanks i and 2
were injured to some extent, and did not make as large a growth
as the others.
Owing to the absence of any periods of low temperature during
the winter, but little protection from cold was needed. The can-
vas tents provided for this purpose were used but three or four
times. The trees in battery I have been fertilized as usual during
the year. No increase over the usual application, 2 pounds, has
been deemed necessary. The trees have made a fair growth this
spring and are evidently making use of a large part of the fertilizer
applied. Owing to the very dry weather this spring, the trees in
the tanks have received additional water at two different times.
The rainfall for the period, April 13, 1912, to April I, 1913,
was 60.66 inches. The amount collected as drainage from the
different tanks is as follows: battery I, tank I, 13.37 inches; tank
2, 12.32 inches; tank 3, 9.67 inches; and tank 4, 8.58 inches. The
average of the four tanks of battery 2 is 16.60 inches. As already
stated, the trees in tanks I and 2 of battery I did not make as much
growth as the others, which probably accounts for the larger
amount of drainage water collected from these tanks.
In battery 2, trees were set out in February. Tank No. 5
will be used as a check, receiving no fertilizer and being without
a tree. Tank No. 6 will receive sulphate of ammonia, floats, and
high-grade sulphate of potash, and beggarweed will be grown
during the rainy seasons. Tank No. 7 will receive nitrate of soda,
Thomas slag, and high-grade sulphate of potash. Tank No. 8
will receive the standard used in tank I of battery I with the ad-
.dition of limestone.

COMPOSITION OF DRAINAGE WATER

BATTERY I.-Table XXVIII shows the composition of the
drainage water as collected in parts per million; table XXIX as
grams per tank.
The data here presented show that the loss of nitrogen is still
large, though considerably less than was found last year. Phos-


xcviii







Annual Report, 9Ir3 xcix

phoric acid is lost in even smaller amounts than was noted last
year. The loss of lime is greater in tanks i and 2 and less in the
others than for the previous year. Potash is lost in considerably
larger quantities this year, the loss averaging about three times
as much as last year.
BATTERY 2.-Table XXX shows the composition of the drain-
age water collected from this battery in the past year. No fertil-
izer has been applied during this period, so that the composition
of the drainage water from the untreated soil is here represented.
The data in this table are comparable with the work on battery
No. I given in the Annual Report for 19II. Comparing the
tables given there with Table XXX, it will be noted that the losses
of fertilizing constituents from the first battery amounted to con-
siderably more than the losses from the second battery.









Florida Agricultural Experiment Station


TABLE XXVIII.

COMPOSITION OF DRAINAGE WATER. BATTERY I. PARTS PER MILLION. APRIL 14,
1912, TO APRIL 2, 1913


Is I

X 0
z z C-Zn


0
0 0
s s Q
!/. n ff


TANK I

June 10 --- 193.9 1.20 .04 231.0 10.3309.8 .05 20. 49.6 137.2 60.9 20.6
July 16 ------- 135.8 .13 .12313.9 13.3 465.2 .10 32.4 87.2243.0 88.7 23.0
Aug. 23 ------110.1 .13 .061258.1 11.8580.8 .39 31.7 98.01288.9 78.9 69.0
Oct. 21 ---130.0 .09 .0408.4 7.8502.8 .26' 25.5 85.8212.3 55.1 59.0
Apr. 1 -- -------116.9 .071- 25.0 9.7338.0 .16 17.3 60.3 135.2 25.0 15.6


TANK 2


June 10 ----------176.71
July 16 ------i-132.11
Aug. 23 ------- 86.01
Oct. 21 ------------130.0|
Apr. 1 ----------- 108.3


.58 .03223.5
.31! .04 340.5
.14 .09199.2
.15 .101 49.3
.06 3.6


14.5 346.0


6.7 502.0|
7.0 301.0


.17 28.4 69.0177.3 63.3 24.0
.06 31.2111.1258.3 59.6 23.6
.20 38.4 73.2 308.5 37.9 52.2
.11 41.4 79.41204.7 24.2 47.2
.15 20.2 56.2123.8 11.6 12.6


TANK 3


June 10 --------- 171.5 .10 .05 299.7i
July 16 ------- 106.4 .10 .04 329.7
Aug. 23 ---- -none collect ed
Oct. 21 ------- 111.2 13 .11137.7
Apr. 1 ---------- 107. .096 174.2


13.7235.8' .12 26.0 49.2 82.0 37.0115.2
14.1 464.6 .08 29.7 40.2 123.3 37.1 140.6

8.6 43.8i .20. 35.1 110.0 100.5 310 183.0
16.3 263.2 .18 20.0 63.01 71.2! 19.3 143.2


TANK 4

June 10 -----------173.7 .141- i 52.31 19.4281.2 .21 32.11 31.2 98.11 47.0 24.2
July 16 ------ 70.5 .141 .02124.9 23.9 444.8 .23' 46.2 55.6 181.91 75.8 33.9
Aug. 23 ---------- none collect ed ----- --- |-- --
Oct. 21 ---- 79.3 .13 .05 77.6 16.91594.6 .44 46.8 64.81225.8 b2.9 100.0
Apr. I ------- 117.1 .25 07 36.6 17.7226.8 .15 31.4 56.21155.6l 81.4 36.8


Date.


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