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

Group Title: Florida Agricultural Experiment station, report for the fiscal year ending June 30th.
Title: Report for the fiscal year ending June 30th
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00005173/00018
 Material Information
Title: Report for the fiscal year ending June 30th
Physical Description: 40 v. : ill. ; 23 cm.
Language: English
Creator: University of Florida -- Agricultural Experiment Station
Publisher: University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1919
Copyright Date: 1905
Frequency: annual
Subject: Agriculture -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
Statement of Responsibility: Florida Agricultural Experiment Station.
Dates or Sequential Designation: 1905-1930.
 Record Information
Bibliographic ID: UF00005173
Volume ID: VID00018
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: ltuf - AMF8112
oclc - 12029638
alephbibnum - 002452807
 Related Items
Preceded by: Report for financial year ending June 30th
Succeeded by: Annual report for the fiscal year ending June 30th ...

Table of Contents
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Page 1
    Table of Contents
        Page 2
    Letter of transmittal
        Page 3
    Board of control and station staff
        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
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Full Text




I -\

ENDING JUNE 30, 1919

With Bulletins 149-153 and
Press Bulletins 292-311

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ENDING JUNE 30, 1919


BOARD OF CONTROL AND STATION STAFF................- ............................. 4R
REPORT OF DIRECTOR ................................................... ........................... 5R
Introduction, 5R; Animal Industry, 5R; Plant Nutrition, 6R;
Entomology, 6R; Plant Pathology, 71; Chemistry, 8R; Forage
Crops, 8R; Changes in Staff, 8R; Publications, 9R; Summary
of Bulletins, 9R; Press Bulletins, 10R.
REPORT OF AUDrrOR .................. ................................................................ 11R
REPORT OF ANIMAL INDUST IALIST............................. ..... .................... 12R
Dairy Herd, 12R; Beef Cattle, 12R; Swine, 14R; Japanese Cane
Fertilizer Experiments, 16R.
REPORT OF THE FORAGE CROP SPECIALIST................................................... 17R
Yields of Japanese Cane, 17R; Variety Test of Sorghums,
17R; Cowpeas, 18R; Miscellaneous Bean Tests, 19R; Napier
and Merker Grass, 20R; Chrysopogon Monticola, 20R; Toda
Grass, 20R; Pasture Grass Plantings, 20R.
REPORT OF PLANT PHY OLO T ................................................. ...... 22R
Phosphoric Acid Experiments With Citrus, 22R.
REPORT OF THE PLANT PATHOLOGIST................ .............................. 31R
Citrus Diseases, 81R; Avocado Diseases, 31R; Castor Bean Dis-
eases, 31R; Gray Mold of the Castor Bean, 32R; Some Impor-
tant Diseases of the Season, 35R.
REPORT OF THE ASSOCITE PLANT PATHOLOGIST .................................... 37R
Bacterial Blight of Potatoes, 37R; Cucumber Bacterial Fruit-
Rot, 39R; Stem-Rot of Corn, 40R; Spraying of Irish Potatoes
to Control Late Blight, 40R; Pineapple Wilt, 42R.
R Pwoa oF CHF rm T ................ ............................................ ................. 43R
Citrus Experiment Grove, 43R; Soil Tank Investigations, 48R;
Miscellaneous, 44R.
REPORT OF ASSISTANT AGRONOMIST .......................................... ....... 46R
Cotton Variety Test, 46R; Peanut Experiment, 46R; Sweet Po-
tato Experiment, 49R.
REPORT OF THE ENTOMOLOGIST ........................................... ................ 50R
Control of Root-Knot Nematodes, 50R; Velvet Bean Caterpillar,
51R; Other Insect Pests of Velvet Beans, 53R; Thrips on Cit-
rus, 54R; Thrips on Peanuts, 55R; The Camphor Thrips, 55R;
Plant Bugs, 55R; Some Insects of the Year, 57R; Castor Bean
Insects, 58R.
REPORT OF THE ASSISTANT ENTOMOLOGIST ............................................. 60R
The Leaf-Footed Plant Bug, 60R; the Big-Legged Plant Bug,

Hon. Sidney J. Catts,
Governor of Florida,
Tallahassee, Fla.
SIR: I have the honor to transmit herewith the annual report
of the Director of the Florida Agricultural Experiment Station
for the fiscal year ending June 30, 1919.
Chairman of the.Board of ControL

J. L. EAEMAN, Chairman, Jacksonville
J. T. DIAMOND, Milton
J. B. HODGEs, Lake City
T. B. KING, Arcadia*
BRYAN MACK, Secretary, Tallahassee
J. G. KELLUM, Auditor, Tallahassee

P. H. ROLFS, Director
J. M. SCOTT, Vice-Director and Animal Industrialist
B. F. FLOYD, Plant Physiologist
J. R. WATSON, Entomologist
H. E. STEVENS. Plant Pathologist
C. D. SHERBAKOFF, Associate Plant Pathologist
S. E. COLLISION, Chemist
J. E. TUBLINGTON, Assistant Agronomist
J. B. THOMPSON, Forage Crop Specialist
S. L. VINSON, Editor
T. VAN HYNING, Librarian
K. H. GRAHAM, Auditor
E. G SHAw, Secretary
RUBY NEWHALL, Bulletin and Mailing Clerk
G. UMLAUF, Gardener
A. W. LELAND, Farm Foreman

*The Board of Control personnel was as indicated at the beginning of
the fiscal year.

Report for the Fiscal Year Ending June 30, 1919

Hlon. J. B. Hodges,
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, 1919; and I request that you trans-
mit the same, in accordance with the law, to the governor of the
State of Florida.

The work of the Experiment Station during the fiscal year
ending June 30, 1919, was in many respects difficult and discon-
eerting, due to problems arising from war conditions. It was
almost impossible to carry on the work of the institution with the
high degree of efficiency it had attained, tho none of the depart-
ment heads was lost due to the war. However, many of the
assistants were lost and temporary assistants had to be employed,
making the work particularly difficult.
The amount of work done cannot be readily enumerated, nor
can the value of it be easily over-estimated. In whatever direc-
tion the emergencies arose, those in charge of the projects
adjusted themselves to meet the changed conditions. Greater'
crop production was necessary and this production had to be
maintained and augmented in spite of anything else that might
happen. The present fiscal year has been the most difficult in
the history of the Experiment Station to obtain efficient and
effective labor. It has also been practically impossible to secure
well-trained assistants at any price, and unfortunately the funds
of the Experiment Station were not elastic and could not be made
to successfully meet the increased prices of material and labor.

The work of the animal industrialist has been continued much
along the line of previous years. Feeding tests with Florida-

Florida Agricultural Experiment Station

grown feeds were continued and the effects on milk production
In beef feeding experiments carried on during the year, to test
the value of peanut meal as a protein feed when checked against
velvet bean meal used as a protein feed, there was a rather dis-
tinct advantage in favor of the lot fed on rations containing
peanut meal.
Extended tests were conducted to determine the effect of feed-
ing velvet beans to brood sows. Much complaint has been made
in the state and in the South generally that the use of velvet beans
as a feed for these animals was distinctly detrimental. So far
as the results of the experiments are concerned, there seemed to
be no good reason for supposing that velvet beans in themselves
had any poisonous effect, either upon the sow or upon the young
at birth.
The experiments in feeding peanut meal to fattening hogs were
continued and conducted with the view of determining how large
a quantity of peanut meal might be used without producing soft
pork. It was also desirable to know what ratio of corn and
peanut meal could be employed to best advantage. The hogs
which were fed equal parts by weight of corn and peanut meal
gave the largest average daily gain.


The work of the plant physiologist was continued along the
lines mentioned in previous annual reports. Extended work was
done to discover the physiological effect of different dosages of
potash and phosphoric acid from different sources.
The work of studying the effects of different plant foods on
citrus trees was carried on more extensively than heretofore. In
some of these experiments results are beginning to come in, so
the valuable effects of several years of experimentation in this
line are being shown.

A large amount of attention was given to the control of root-
knot-producing nematodes. This serious pest of the truck crops
of Florida is probably the worst pest with which farmers and
orchardists have to contend. Careful and detailed attention was
given to the use of cyanide and sulphate of ammonia as a treat-
ment for the destruction of these worms. For truck fields 600

Annual Report, 1919

pounds of sodium cyanide and 900 pounds of ammonium sulphate
would seem to be about the most practical dose to apply. This
does not result in total destruction of the nematodes but so
reduces their number that they will not become troublesome
before the first truck season is over. On seedbeds, where it is
desirable to produce as nearly a total destruction as possible, 800
pounds of sodium cyanide and 1,200 pounds of ammonium sul-
phate produce the best results. Ammonium sulphate alone
required a dosage of 1,800 pounds to the acre to make a great
reduction in the number of nematodes. Summer fallowing, a
method of destroying nematode worms, discovered by the Florida
Experiment Station, continued to give good success. Attention
was called to the fact that the frequent cultivation of the soil
infected is an essential part of the fallowing. This discovery
would seem to add materially to the possibilities of the control
of this pest.
The work on thrips was continued. Many valuable observa-
tions were recorded and much progress was made toward the
control of a number of species belonging to this general group.
Careful and extended study was made on the life history of the
larger plant bugs. Several parasites of these bugs were studied
in detail.

The work of the plant pathologist has been slightly broadened
to include the study of avocado diseases, which were reported
from the southern portion of the state, and a brief study seemed
to indicate the appearance of a new disease.
The work previously begun on citrus diseases was carried for-
ward and a reasonable amount of progress was made in the direc-
tion of discovering the causative agent for some of the diseases
that heretofore had not been well understood.
The investigation of truck crop diseases was continued and the
field experiments were considerably extended and enlarged. Par-
ticular attention was given to diseases affecting Irish potatoes
and cucumbers. An interesting piece of work was conducted for
the control of the bacterial blight of the Irish potato caused by
Bacillus solanacearum. The results of experiments with different
fertilizing materials show no marked increase or decrease in the
amount of disease present.
Carefully planned work was begun on pineapples in order to
prevent and control a disastrous disease of this crop known

SR Florida Agricultural Experiment Station

among the growers as pineapple wilt. The exact factors pro-
ducing or augmenting this disease are not well understood.

The projects on soils and fertilizers were continued as outlined
10 years ago. This part of the work is nearing completion so far
as the first phase of these studies is concerned. As a result of the
10 years' work, several of the sources of nitrogen have proved to
be about equally satisfactory so far as growth production is con-
cerned. Among the different elements used as a source of phos-
phorus, phosphoric acid seemed to give better growth than the
other forms which were tested. A formula composed of sulphate
of ammonia, sulphate of potash and acid phosphate gave the
most satisfactory results. Part of the experiment was to deter-
mine the effects of maximum fertilizing. This showed quite clearly
that citrus trees are able to adjust themselves to adverse condi-
tions produced by over-fertilization, and that over-fertilizing has
a more marked retarding effect on growth than quantities below
the optimum. The entire work on the citrus grove was published
in Experiment Station Bulletin 154.

The work in forage crop experiments was extended and plots
were located in 12 different counties. It is not intended that these
shall be carried forward as permanent stations, but rather to
test the value of from 12 to 14 different forage crops that might
prove successful in the immediate localities, care being taken not
to include any of the forage crops that have already become
The work carried on under the Hatch fund may be divided
into two parts: that conducted by the animal industrialist and
that carried out by the director for the benefit of the whole
station. The project conducted by the animal industrialist in-
cludes a considerable amount of what might be termed as agron-
omy research, especially such work as is closely related to the
Animal industry line.
The changes in the Station staff were few and of minor
G. C. Oberholtzer resigned as farm foreman, effective August

Annual Report, 1919

31, 1918. On September 1, 1918, A. W. Leland took charge of the
Experiment Station farm as foreman.
SOn April 21, 1919, Philip A. Macy accepted the position as
assistant chemist, which work he continued thruout the year.
On March 1, 1919, Evelyn Osborn took up the work as assistant
entomologist and continued until June 30, 1919.
Carl T. Link took up work as laboratory assistant in plant
pathology on February 2, 1919, and continued thruout the year..
A. M. Smith resigned August 15, 1918.


Following is a list of publications issued by the Experiment
Station for the fiscal year ending June 30, 1919:
Bulletin Total
Number Title Edition Pages Pages
149 Some Diseases of the Fig.................. 15,000 12 450,000
150 Florida Citrus Diseases .............. 20,000 98 1,960,000
151 Florida Truck and Garden Insects ... 8,000 102 816,000
152 Velvet Bean Varieties ................ 20,000 22 440,000
153 Napier and Merker Grasses.............. 20,000 16 320,000
Totals.... ........ ......- ...... ............83,000 250 3,716,000
Annual Report, 1917-18, with index to all
publications for the year......................... 4,000 100 400,000

149. Some Diseases of the Fig (J. Matz), pp. 12, figs. 5. A
discussion of the important diseases of the fig, and control
150. Florida Citrus Diseases (H. E. Stevens), pp. 98, figs. 49.
This bulletin takes up the diseases that are apt to be found in the
Florida citrus grove, describing their appearances, causes, and
methods of control. It is meant as a practical handbook for the
citrus grower.
151. Florida Truck and Garden Insects (J. R. Watson), pp.
102, figs. 56. This bulletin describes the most important insects
and other animals in Florida truck fields and gardens, gives an
account of their life history and states the best methods for their
control. Formulas for the more common insecticides are included.
152. Velvet Bean Varieties (John M. Scott), pp. 22, figs. 10. A
full description and history of the principal varieties of velvet
beans are given in this bulletin. Each variety is illustrated.
153. Napier and Merker Grasses (J. B. Thompson), pp. 16,
figs. 7. This bulletin reports the results of experiments with

Florida Agricultural Experiment Station

these grasses at this Station, and gives observations on coopera-
tive plantings made at various points thruout the state. The
habits of the two grasses, methods of propagating and planting
them, soil requirements, yields, and feeding values are discussed.

1So. Title Author
292 Summer Fallow for Root-Knot-Infested Land..J. R. Watson
293 The Fall Army Worm or Grass Worm.............J. R. Watson
294 Castor Beans Attacked by Corn Ear-Worm....J. R. Watson
295 Gas the Ants ................................................... J. R. Watson
296 Gray Mold of Castor Beans.......-......................H. E. Stevens
297 The Purple Scale ................................ ..........J. R. Watson
298 Cottony Cushion Scale ......................... ...--. J. R. Watson
299 Preserving Fungous Parasites of Whitefly ...... R. Watson
300 Citrus Fruit Rots-...........................-...-..... H. E. Stevens
301 Napier Grass.................................................J. B. Thompson
302 Fertilizers for Sweet Potatoes..........................J. M. Scott
303 Bulletin List ........................ .......... ...................
304 Sweet Potato Caterpillars ............-..................J. R. Watson
305 Silage and Silage Crops................J. B. Thompson
306 Velvet Beans for Brood Sows.......................John M. Scott
307 Steer Feeding Expcriment..........-......-... John M. Scott
308 Para Grass.....................................................J. B. Thompson
309 Bulletin List........................... ... .. ......................... .....
310 Dalis Grass........... ............................J. B. Thompson
311 Hog Management....................................A. P. Spencei


Annual Report, 1919


P. H. ROLFS, Director. -
SIm: I respectfully submit the following report of the credits
-received and expenditures vouchered out of funds as specified
during the fiscal year ending June 30, 1919.


Adams Fund ................. ...............
Hatch Fund..........................
State Experiment Fund .-.........
State Repair and Building Fund...
State Printing Fund. .............
Sales, Farm-.................................
Forage Crop Fund ..........-........ .....
Miscellaneous .....................................









Hatch Adams
Salaries ................................................ $6201.65 $10,012.31
Labor .................................... .. 3,409.22 1,115.28
Publications ..................... 2250.39 ..............
Postage and stationery.......... 554.59 108.53
Freight and express .... ........... 93.35 241.31
Heat, light, water and power .. 211.68 67.57
Chemical and laboratory supplies- 3,75 779.18
Seeds, plants and sundry supplies 183.34 367.75
Fertilizer .......... ..... .. ..... 44.64 109.99
Feeding stuffs................................. 1,265.97 .............
Library ................ ..... ..... 316.20 53.74
Tools, machinery and appliances.._ 279.33 285.94
Furniture and fixtures. ............. 5.89 196.54
Scientific apparatus and specimens 4.03 287.06
Livestock .. .............. .........................
Traveling expenses ........................ 118.97 1,309.94
Contingent expenses...................... 20.00....
Buildings and land............................ 37.00 64.86
Balance .. .......... .............. ........ .............. ..............

$15,000.00 $15,000.00







Florida Agricultural Experiment Station

P. H. ROLFs, Director.
Sm: I submit the following report of the Department of Ani-
mal Industry for the fiscal year ending June 30, 1919.
Animal Industrialist.

A few of the poorer producers in the herd have been sold, but
the herd has been increased by retaining the heifer calves from
the best producing cows. The total number of cattle now in the
herd is 73, of which 40 are purebred Jerseys; 37 of these are

Table 1 gives a record of the herd in detail.

In a cattle-feeding experiment conducted in cooperation with
L. K. Edwards of Irvine, Florida, 10 grade Angus steers were
used. These steers were out of native cows by a purebred Angus
bull, and were about 18 months old when the experiment began.
The steers were divided equally into two lots, and were fed for
120 days.

The steers in lot 1 were fed shelled corn, velvet bean feed
meal and silage. The steers in lot 2 were fed shelled corn, pea-
nut feed meal and silage. For each 21/. pounds of shelled corn,
1 pound of velvet bean feed meal or peanut feed meal was fed.
These proportions proved quite satisfactory. (See Table 2,
next page.)
When the steers were on full feed each animal consumed 12%
pounds of shelled corn, 5 pounds of velvet bean feed meal or
peanut feed meal, and about 16 pounds of silage each day.
By velvet bean feed meal and peanut feed meal is meant that
the velvet bean hulls and peanut hulls are ground up with the
beans and peanuts.

Annual Report, 1919


I lg I

0 0
o IL W P! -5 -

I .... Grade Jersey 3,586.3 365 4.9 175.7 417.0 i $88.40
7 ... Grade Jersey 617.2 96 38 23.4 71.7 14.55
9 ... Grade Jersey 4,275.9 365 4.8 205.2 497.2 108.57
18 8 Jersey 4,993.5 328 4.5 224.7 580.6 184.83
20 7% Jersey 2,741.4 255 4.1 112.3 318.7 72.90
31 6 Jersey 2,503.8 255 4.8 120.1 2911 60.68
33 6 Jersey 2,480.9 291 4.4 109.1 288.4 65.03
35 6 Grade Jersey 2,885.4 234 4.8 138.4 335.5 74.54
36 1 6 Grade Jersey 4,366.5 302 4.5 196.4 507.7 82.12
41 1 7 Grade Jersey 1,646.0 177 4.3 70.7 191.3 38.31
42 10 i Grade Jersey i 2,917.8 254 4.2 122.5 339.2 71.76
47 5 Jersey 3,199.7 279 5.0 159.9 372.0 83.06
49 5 Grade Jersey 1,865.2 273 5.2 96.9 216.8 64402
50 5 Grade Jersey 3,693.7 277 4.8 177.2 429.5 81.99
52 5 Grade Jersey 2,160.0 i 241 3.4 73.4 251.11 56.55
53 5 Jersey 2,258.0 199 3.8 85.8 262.5 45.22
54 5 Grade Jersey 2,401.2 272 I 4.6 110.4 279.2 77.66
55 5 Grade Jersey I 1,459.6 171 4.8 70.0 169.7 40.34
56 4% Jersey 1,710.4 228 4.5 76.9 198.8 44.88
57 4% Grade Jersey' 2,884.7 273 i -48 138.4 I 355.4 77.56
59 7 Jersey 4,177.2 273 1 4.2 1 175.4 485.7 7&69
61 7 1 Grade Jersey 4,090.7 311 1 3.9 159.5 I 475.6 84.24
66 4 Jersey 1,797.4 197 4.8 86.2 209.0 45.70
68 ... I 2,293.2 240 4.6 105.4 266.6 58.25
69 6 Grade Jersey 4,283.4 241 I 4A 188.4 498.0 80.51
71 .... I I 188.7 1 31 5.6 10.5 21.9 14.21
72 .... 606.8 106 .. ...... 70.5 18.71
73 3 Grade Jersey 3,672.6 279 4.2 154.2 | 427.0 96.31
74 3 Grade Jersey 1,349.1 91 3.6i 48.5 156.8 27.49
75 3 Jersey j .......... .... .. ... ........
77 3 Jersey 1 938.5 180 4I9 45.9 109.1 29.70
79 3 Grade Jersey 1 433.9 25 4.5 19.5 50.4 6.42
81 4 Jersey I 2,978.8 1 256 4.1 122.1 346.3 73.07
84 3 Grade Jersey ...... ...... .....
85 2 Jersey 5135 6 0 .5 60 6.0 19.00
104 4% Jersey I 3,069.2 258 3.7 83.5 356.8 70.65
106 4 Jersey I 946.4 156 4.2 39.7 110.0 35.51
109 4% Jersey 5,833.0 336 4.1 239.1 678.2 110.85
115 9 Jersey 3,057.6 260 4.1 125.3 355.5 61.45
117 8 Jersey 435.7 67 4.8 20.9 50.6 11.07

_I Lot_ 1 Lot2
5 steers at beginning, Dec. 20, 1918, averaged in pounds ....... 599 593
5 steers at close, April 19, 1919............................. .. ........ 857 854
Average gain per head in 120 days...................................... 258 261
Average daily gain per head. ............................................... 2.15 2.17
Average daily gain per 1,000 pounds live weight.................... 3.58 3.65
Pounds of grain for 100 pounds of gain .................. 1 713.56 705.36

Florida Agricultural Experiment Station

The steers made satisfactory gains, which showed that a com-
bination of corn and velvet bean feed meal or corn and peanut
feed meal were satisfactory for beef production.
Observations made during the above test indicate that when
fed with corn and silage, about 5 pounds per day per head of
either peanut feed meal or velvet bean feed meal was about the
limit. Peanut feed meal seemed to be very laxative. Perhaps
when given with other feed more of it could be fed.

During the last two years a number of hog raisers have
reported the loss of a large percentage of pigs at farrowing time
or shortly thereafter and the feeding of velvet beans had been
thought to be the cause of the loss.
On November 1, 1918, six brood sows-five Berkshires and one
Chester White-and one Berkshire boar were put on experiment
to test out the effect of a ration composed largely of velvet beans.
The feeding pens were arranged so that each sow would be fed
separately, and the feed for each animal was prepared and fed
separately. From May, 1918, up to the beginning of the experi-
ment, part of the sows selected to be used in this experiment had
been fed a ration composed of corn and velvet bean feed meal.
The feeds used were ground corn and velvet bean feed meal,
mixed in the proportion of 1 part ground corn and 2 parts vel-
vet bean feed meal. This mixture was placed in a bucket and
enough water added to make a thin slop, and soaked for 24
hours. The hogs were given no water except that in which the
corn and velvet bean feed was soaked. One pound ground corn
and 2 pounds velvet bean feed meal, mixed with a gallon of
water, was given each animal twice daily.
During this entire test these sows were given no other feed
except as stated above. No green feed was given at any time.

On November 11 it was noted that the Chester White sow was
sick. Her feed was changed and green feed added to the ration.
She continued sick, and died during the night of November 26.
On the morning of November 27, Dr. John Spencer made a post


Annual Report, 1919

mortem examination and pronounced the trouble yellow atrophy
of the liver.
January 30, 1919, sow No. 1 farrowed six pigs, three of which
were dead when found. From all indications these pigs were
born dead. During the night of February 2 the three remaining
pigs disappeared. It is supposed that the sow ate them.
On March 2, sow No. 2 farrowed 12 pigs. These were all
strong, well developed pigs.
March 8, sow No. 3 farrowed (a few days earlier than was
expected) and was left in the yard with sows No. 4 and No. 5 and
the boar. The pigs disappeared, and it is believed that the other
sows ate them.
On March 28, sows No. 4 and No. 5 farrowed eight pigs each.
These were all strong, well-developed pigs.
On December 19, 1918, a feeding experiment was started,
which continued to April 17, 1919, 16 hogs being used. The hogs
were divided into four lots of four pigs each. The hogs averaged
a little over 100 pounds each.
The object of the experiment was to determine how much
peanut meal feed could be added to a corn ration for hogs and still
produce hard pork.

1 4 488.0 555.0 67.0 16.75 .48
2 4 513.0 615.0 102.0 25.50 .73
3 4 495.0 580.0 85.0 21.25 .61
4 4 441.0 525.0 84.0 1 21.00 .60
J January March
I23,1919 1,1919
1 4 555.0 630.0 75.0 18.75 .53
2 4 615.0 675.0 60.0 15.00 .43
3 3 9500.0 580.0 80.0 26.60 .76
4 4 4525.0 593.0 68.0 17.00 .48
SJMarchy April
1,1919 17,1919 1
1 3 551.0 -623.0 73.0 37.66 .78
2 2 394.0 435.0 41.0 20.50 .42
3 3 580.0 645.0 65.0 21.66 .45
4 4 593.0 661593.0 68.0 17.00 .648
5 2 281.0 306.0 I 25.0 12.50 .26


Florida Agricultural Experiment Station


The feeds used were different proportions of corn and peanut
meal. The hogs in lot 1 were fed corn only. Those in lot 2 corn
and peanut meal feed, equal parts by weight. Those in lot 3 corn,
peanut meal feed and velvet bean feed, equal parts by weight.
Those in lot 4, corn 2 parts and peanut meal 1 part, by weight.
On March 1 the pigs in lot 2 were divided, making lot 5, which
was fed a ration composed of corn and cottonseed meal.

Fertilizer experiments with Japanese cane have been conducted
at the Station since the spring of 1909. This gives the results of
10 years' work from which to draw conclusions. This work has
not only been carried on for 10 years, but the experiments have
been conducted on the same piece of land and the same fertilizers
have been used during all of this time.
The Japanese cane was replanted after harvesting the 1914
crop and again after harvesting the 1917 crop.
The yields obtained from year to year show clearly that it is
not only advisable, but necessary, to replant Japanese cane every
few years if we wish to maintain a satisfactory yield. Replant-
ing of the cane has had more effect on producing large yields than
has the fertilizer.

Plot 1 I 2 3 4 5 1 617 8
Dried blood ............................. 112 ...... 112 I ...... 112 ...... 112 112
Sulphate of ammonia........... I .... ..... ...... .....
Muriate of potash.......... ..1 84 84 ...... 84 84 1 ..... ...
Sulphate of potash.................. ...... .. ...... ..... 84 1 84 84
Acid phosphate....................... --.. 224 224 224 24 ,224 224 224
Ground limestone.................... ............ ...... ...... ...... 2,000
I~- I- ---
Total................................ 196 308 336 380 420 880 420 2,420
P 9 I | 1 1 (Replanted) 1 I I (Replanted)
Plot 19091 19101 1911 19121 1913 1914 1915 1 1910171 1918_
1 124.20114.60 7.081 6.381 8.16 5431 29.5 21.4 0.96 28.8
2 !17.70112.40 9)00 6.84 6.93 5.05 31.9 15. 2.16 24.0
3 116.1010.00 9.63 3.68 3.83 2.07 18.0 3.81 0.0 23.04
4 119.10114.40114.61 7.921 8.51 6.87 24.2 12.5 2.4 26.68
5 i19.54111.8013.561 7.261 8.09 5.25 29.7 10.6 3.7 23.52
6 118.9016.70115.481 9.621 7j8 6.73 24.9 I 9. 3.7 18.72
7 116.604.10114.02110.681 9.33 7.26 27.3 7.7 2.4 19.68
8 127.08 16.00114,0110.281 8.921 5891 22.5 | 12.2 5.2 1 12.48


Annual Report, 1919

P. H. ROLFS, Director.
SIR: I submit the following report of the forage crop specialist
for the fiscal year ending June 30, 1919.
Forage Crop Specialist.

On March 9, 1918, a plot of land slightly in excess of a quarter
of an acre was planted to seed canes of one of the improved varie-
ties of Japanese cane, No. 29,106. The object of the work was to
measure the relative productivity of the soil as a check upon the
yields of various less-known crops grown on the same class of
land, and partially to obtain additional data on successive crop
yields. The land was newly cleared and might be described as
rather good pine land. As was the case with all other forage crop
tests conducted on this ground and recorded on the following
pages, no fertilizer was applied in the production of this crop.
The crop from this planting was cut for the silo on November
14, 1918. The product of a representative interior row was
weighed, giving a total yield of 1,855 pounds, or an equivalent of
32.27 tons to the acre. There was a distinctly noticeably increased
marginal growth, and the outer row, when cut and weighed,
returned a yield of 2,395 pounds, or 29 percent greater than that
Produced on an interior row. This cane was planted in rows 6
feet apart.
Two other varieties of sugar cane, "Cayana 9" and "Cayana
10," were grown for the first time during the year. So far as the
test has progressed they do not show a vigor of growth equal to
that of Japanese cane.
A variety test of sorghums of the non-saccharine group was
conducted during the year. Each variety was planted on March
25, 1918, and was harvested on July 17 of the same year. Table 6
shows the yields of green feed from the different varieties after
being cut and exposed for a period of three hours to the hot sun.
A test of grain sorghums was also undertaken during the year.
Shallu or Egyptian wheat, milo and kafir corn were planted on
April 2, 1918. The sorghum midge was observed to be more or


Florida Agricultural Experiment Station

less plentiful during the seeding or flowering period, but did not
particularly interfere with seed development.

Sugar drip.................... ............... ....
Red Top or Sumac.......... ....................
Japanese Honey .... ...... ...........
Texas Seeded Ribbon -. ........
Early Amber ... .. ... .. .........
Early Orange ...... ... ....... : ........ .._

I Pounds Per Row I Pounds Per Acre
S 725 48,210
S 470 28,012
445 26,522
380 22,648
815 18,774
275 16,390

For the purpose of comparing the yields of feed, a planting was
made of six of the common cowpea varieties. The planting was
made on new pine land and no fertilizer was used. The land hav-
ing been idle for a period of several years, it was apparently free
from nematodes and consequently none of the varieties were
affected by root-knot. A mould-like fungus was observed on the
pods of all varieties. It was most noticeable on pods after they
had begun to ripen, and was also observed to develop on the fallen
corollos of the cowpea flowers. The crop from these varieties
was cut on July 17 and the various yields when cut and weighed,
after being exposed for three hours to the heat of the sun, are
recorded in Table 7.

Large Blackeye..................... ........
Lady Peas.................................... ........
Clay ................................... ................
Whippoorwill .......................... ..........
Brabham ..... ........ .................
Wonderful or Unknown .....-..............

Pounds Per Row Pounds Per Acre
40 2,384
200 11,920
260 16,496
285 17,486
340 20,264
380 22,648

A small, twining wild cowpea, Vigna repens, the seed of which
was collected near Jupiter on November 24, 1917, was grown
during the summer of 1918. This plant as grown in the open
field, without support, has trailing stems that reach out to a dis-
tance of from 10 to 15 feet and become attached to the ground by
means of roots sent out at intervals on these surface rVnners.
The flowers are smaller than those of the cowpea and are yellow
in color. The vines when given opportunity tend to climb. The
seed were drilled in 314-foot rows on April 3, 1918, and by July 15
the vines had completely covered the ground and measured from
5 to 6 feet in length. The vines continued in vigorous growth


Annual Report, 1919

thruout the summer, and, unlike cowpea, did not mature and cast
their leaves at the close of a short growing period. This rank and
thrifty growth continued until injured by a light frost on Novem-
ber 14, the leaves remaining green and in perfect tact until that
time. In the latitude of Gainesville it showed sparse seeding
habits, but it flowered and seeded freely in Palm Beach County.
It possesses leafy characteristics, fineness of growth, vigor, and
the habit of retaining its leaves for a long period without appar-
ently developing a harsh woody texture. These are all desirable
characteristics that might commend this species to the plant
breeder who is engaged in the work of improving the cowpea thru
crossing and hybridization.


A few varieties of beans, tho not primarily important as forage
possibilities, were tested in a limited way. The Tepary and the
New Mexico Pinto, two important field beans of the arid South-
west. were planted on April 2, 1918. The Tepary bean showed a
tendency to continue growth and production over a rather
extended period. Four pickings of this variety were made, the
first and last dating June 21 and July 25, respectively. The
product maturing in a dry period was of good quality, but that
coming on during a period of even moderate rainfall was badly
damaged. The total yield per season was at the rate of 211
pounds, 59 pounds of which were of poor grade. This variety is
probably more desirable under conditions where there is less
rainfall. '
The New Mexico Pinto bean matured uniformly, the endie
yield being harvested in two pickings, on June 2 'nd June 28.
The quality of the beans was good, tho it is sigpiiicant that the
crop was harvested before the advent of the rainy Ae isoti; /I 'T '
total yield for the season was at the rate of 228 pounds to the
acre, all being of good marketable quality.
The Monstrous Bush bean, a prolific Southwestern .variety, wq. s'
tested, but made a complete failure, not one be6a rc ,
maturity, as the flowers and young fruit shed prematurely.
Two strains of the Adzuki bean, Phaseolus angularis, were
tested for seed production. They were planted on April 24, 1918.
The plants made a vigorous growth, showing remarkably prolific
seeding habits; but they were assailed from time to time by pests
that resulted in an almost complete loss of the crop. Among these


Florida Agricultural Experiment Station

pests were the lesser corn borer, Elasmopalpus lignosellus, the
cowpea weevil and the root-knot nematode. The final yield
amounted to the equivalent of 751/ pounds of dry beans to the
acre; all were badly damaged by the cowpea weevil.

Napier and Merker grasses were tried out and both appear to
be promising additions as forage crops for livestock. Seed were
generously distributed by the Experiment Station and these
grasses are being tried in all areas of the state.

This grass, as observed at the Experiment Station, is an
upright-growing, leafy perennial, measuring from 3 to 5 feet in
height. It makes rapid growth in early spring and has shown
considerable promise for planting on light sandy soils. It seeded
profusely on the trial plots, but there is question as to the viability
of the seed. A germination test of seed produced during the
season of 1918 was begun on February 27, 1919, and 19 percent
of the seed were found to grow.

Toda grass, Andropogon foveolatus, a species that had pre-
viously shown exceptional promise from the viewpoint of produc-
tion, was again under observation during the fiscal year. It
develops a fragrant oil that imparts a bitter and undesirable taste
to the feed. Andropogon odoratum, another species containing a
similar oil, has been grown at the Station since 1916, while Lemon
grass, Andropbgon nardus, a tropical species from which Citro-
nella, oil of commerce is distilled, is a familiar example of a grass
'of this 'type. It seems improbable that Toda grass will assume
importance as a forage crop.

A large number of pasture grasses have been grown experi-
mentally at the Station during the last few years. In many cases
these tests have shown conclusively a lack of adaptation, and
have been discarded. A few grasses, however, seem promising,
and have been retained for further observation. Grazing tests
are contemplated to include the planting of approximately a tenth


Annual Report, 1919 21R

of an acre to each of the following grasses: Ordinary Bermuda,
Giant Bermuda, Blue Couch, Kikuyu, Paspalum notatum, Pas-
palum larranagai, Napier, Merker, St. Augustine grasses,
maiden cane, Panicum hemitomon and Chrysopogon montanus.
The last named species will be planted from the seed, while all
others will be set with plants or cuttings.
This planting should provide information on the feeding pref-
erences of stock for the different grasses, as well as to their
persistence and ability to withstand trampling.

Florida Agricultural Experiment Station

P. H. ROLFS, Director.
SIR: I submit the following report of the plant physiologist
for the current fiscal year ending June 30, 1919.
Plant Physiologist.

The principal work of this department during the year has
been in fertilizing experiments of Irish potatoes and with experi-
ments in the fertilization of citrus trees. Much data has been
obtained on both of these subjects and, as the data in connection
with the fertilization of Irish potatoes is to appear in a short
while in bulletin form, this report will be concerned entirely with
the citrus experiments which are being carried on and to be
continued over a long period of years.

These experiments are a continuation of those which are being
conducted at Lake Alfred in cooperation with the Florida Fruit-
lands Company and at Lowell in cooperation with the Wetumpka
Fruit Company. Their purpose is to determine the relative value
of acid phosphate, steamed bone, finely ground pebble phosphate
and soft phosphate when used as sources of phosphoric acid in
complete fertilizers for citrus trees.
The basic formula used was one analyzing 4 percent of ammonia
for the spring application and 3 percent of ammonia for the sum-
mer and fall applications, excepting where the appearance of the
trees indicated the need of more ammonia. No potash had been
used in the formula until the summer application of 1919, at
which time 3 percent was used in the experiments at Lake Alfred
and 4 percent in the experiments at Lowell. Where acid phos-
phate was the carrier, 8 percent of available phosphoric acid was
used in the formula; 16 percent total phosphoric acid where
steamed bone was used; and 32 percent total phosphoric acid
where the soft and pebble phosphates were used.
The sources of ammonia and potash used in making the formula


Annual Report. 1919

were sulphate of ammonia, nitrate of soda, dried blood and sul-
phate of potash (Nebraska potash).
With one exception, fertilizer treatments this year were con-
tinued practically the same as during the previous year. Begin-
ning with the spring application of fertilizer in 1919, hoof meal
has been substituted for the dried blood. The reason for this
change was that the type of tree growth indicated a controlling
influence of the organic ammonia upon growth. This was not
considered desirable. The hoof meal was substituted because it
was less available and more comparable to the organic ammonia
contained in the steamed bone.
The experiments are being conducted (1) with young trees at
Lake Alfred planted on virgin land. (2) with young trees at Lake
Alfred that had received fertilizer treatment previous to the
time the experiment was started, and (3) with old trees that were
in bearing at the time the experiment was started.
The outline of these experiments is given in detail in the
Annual Report of this Station for 1918 on pages 39R to 50R, and
will therefore not be repeated here. This report contains only a
discussion of changes that may have been made in the plan of the
experiment and of the results that have been obtained during the
fiscal year.

The trees in this experiment were given ammonia alone in the
springs of 1918 and 1919. In 1918 the amount given was equiva-
lent to 1 pound to the tree, irrespective of kind, of a basic formula
analyzing 4 percent of ammonia, of which half was carried as
nitrate of soda and the remainder as sulphate of ammonia. In
1919 the amount was equivalent to 21,/ pounds of the basic for-
mula per grapefruit tree and 2 pounds per orange tree.
At the summer and fall applications of 1918 ammonia and
phosphoric acid were applied irrespective of the kind of tree. The
amount applied was equivalent to 1!/ pounds of the basic for-
mula, analyzing 3 percent of ammonia and 8 percent of available
phosphoric acid, or 16 percent, or 32 percent total phosphoric
acid according to the source used. No potash was used in these
In the summer of 1919 ammonia, phosphoric acid and potash
were applied. The amount given each grapefruit tree was equiva-
lent to 21/ pounds of a basic formula analyzing the same as that


Florida Agricultural Experiment Station

used in the summer of 1918, with the addition of 3 per cent of
potash. Each orange tree received 2 pounds of the same formula,
with the addition of 3 percent of potash.
The trees have made a rapid and satisfactory growth from the
time they were planted in Juanary, 1917. Excepting where
insects or diseases have attacked the trees and caused damage,
they are very uniform in size and development. To the eye the
trees have made as satisfactory growth with the insoluble phos-
phates as with the soluble.
In November, 1917, a measurement was made of the diameters
of the trunks of the trees at a point 6 inches above the bud union,
as a basis for keeping a record of the increased growth due to the
different fertilizer treatments. In August, 1918, a second meas-
urement was made and in June, 1919, a third. Table 8 shows the
average increase (in terms of 32nds of an inch) of the diameters
of the trunks of the trees 6 inches above the bud union, from
November, 1917, to June, 1919. These records do not include the
increase in diameter of the trees in the buffer rows.
FaoM NovEMBER, 1917, To JUNE, 1919, IN 32NDS OF AN INCH.
p Acid Steamed Soft i Pebble
_ phosphate bone phosphate I phosphate
Grapefruit 40 35 33 36
trees 31 32 32 26
Total 71 67 65 62
Average increase 36 34 33 31
Orange 28 24 26 22
trees 26 28 25 ....
Total 54 52 51 22
Average increase 27 I 26 26 22

It is thus seen that while the increase in diameter of the trunks
of all of the trees in the experiment in the 19 months has been
large, the variations with the different fertilizers has really been
(In the experiment with young trees planted on virgin land,
practically no fertilizer had been added to the soil previous to the
time the experiment was started.)
This experiment is one in which older trees were used. They


Annual Report, 1919

had been given regular applications of a complete commercial fer-
tilizer from the time of planting in March, 1914, to and including
the summer application in 1917. Thus it is quite probable that
considerable quantities of phosphoric acid had accumulated in the
soil from previous applications that would influence the growth of
the trees during a year or more after the last application of fer-
tilizer had been made (summer of 1917). That this is probable
is easily shown by the results of the leaching experiments con-
ducted by the chemistry department of this Station. This experi-
ment is therefore conducted to study the influence of previous
fertilizer treatments of the soil upon the availability of the dif-
ferent sources of phosphoric acid as measured by tree growth and
The experiment was begun in November, 1917. The plots are
arranged in the same order and the same fertilizers were used
in the two experiments. The only difference is in the amount of
fertilizer applied.
During the springs of 1918 and 1919, ammonia alone was
applied to the trees. The amount given each tree in 1918 was
equivalent to that contained in 4 pounds of the basic formula
described above. During the spring of 1919 the amount applied
to each grapefruit tree was equivalent to that contained in 6
pounds of the basic formula. That applied to each orange tree
was equivalent to that contained in 5 pounds of the formula.
In the summer and fall applications of 1918 ammonia and phos-
phoric acid in amounts equivalent to those in 5 pounds of the
basic formula were applied to each tree. In the summer of 1919
ammonia, phosphoric acid and potash in amounts equivalent to
those in 6 pounds of the basic formula were applied to each grape-
fruit tree and 5 pounds to each orange tree.
Acid I Steamed Soft I Pebble
Sphosphate i bone phosphate I phospl-ate
Grapefruit 34 35 i 33 33
trees 33 35 35 32
Total 67 70 68 65
Average increase 34 35 34 33
Orange 25 28 24 26
trees 27 26 24 25
Total 52 54 48 51
Average increase 26 27 24 26

Florida Agricultural Experiment Station

Measurements were made of the diameters of the trunks of
trees at a point 6 inches above the bud union in November, 1917,
August, 1918, and June, 1919. Table 9 shows the average
increase in diameter of the trees in the different plots between
November, 1917, and June, 1919. They are expressed in terms of
32nds of an inch in order to make them easily comparable to the
data obtained from the fertilizer experiment conducted from 1909
to 1919 at Tavares by the chemistry department of this Station.
From Tables 8 and 9 it is seen that, as in the previous experi-
ment, the general increase in size of the trees has been large, but
the variations in increase due to the different sources of phos-
phoric acid used are negligible.
The purpose of this experiment is to determine the influence of
different sources of phosphoric acid when used as a part of a
complete fertilizer, upon the growth and yield of bearing trees.
The experiment was started in 1917 w!th bearing trees that had
been severely cut back by the cold in the spring of 1917. The
trees were more than 25 years of age and had been fertilized
rather heavily with complete commercial fertilizers up to 1917.
The first application of fertilizer as a part of the experiment
was made in December, 1917. Practically the same basic formula
was used as at Lake Alfred. The sources used in making up the
formulas differed in that nitrate of soda was used as one of the
sources of ammonia. Beginning with the summer application of
1919 hoof meal was substituted for dried blood.
The amount of fertilizer applied to each tree at this application
(December. 1917) varied according to the size of the tree. This
is described in detail in the Annual Report of this Station for
1918 on pages 46R and 47R. The trees were graded according
to size, into 1-unit, 2 unit, 3-unit and 4-unit trees.
A 1-unit tree was given 1/4 pound of ammonia and an amount of
phosphoric acid that varied according to the following conditions:
One-half pound of available phosphoric acid where acid phos-,
phate was the only source of phosphoric acid used; or 1/2 pound of
available phosphoric acid where acid phosphate and steamed bone
were used together as the sources, assuming that half of the total
phosphoric acid in steamed bone was available; or 1 pound of total
phosphoric acid where steamed bone was the only source of phos-
phoric acid used; or 2 pounds of total phosphoric acid where soft
phosphate or pebble phosphate was the only source used.


Annual Report, 1919

A 2-unit tree was given twice the amount of ammonia and phos-
phoric acid given a 1-unit tree; a 3-unit tree, three times; and a
4-unit tree, four times that amount. In the spring of 1918
ammonia alone in the form of nitrate of soda was given the grove.
The summer application of fertilizer in 1918 was applied late
(in July) and was a duplication in kind and amount of that
applied in the fall of 1917.
No fertilizer was given the grove in the fall of 1918. The trees
appeared to be well fed and did not show any need of it.
At the spring application of 1919 both ammonia and phos-
phoric acid were given the trees. This application was a duplica-
tion of that applied in the fall of 1917 and the summer of 1918,
excepting in amount. The amount of fertilizer given 1-unit trees
was increased by 100 percent; that given 2-unit trees, 50 percent;
that given 3-unit trees, 33 1-3 percent. No change was made in
the amount given 4-unit trees.
In the summer of 1919 this application was duplicated, and in
addition some sulphate of potash (Nebraska potash) was applied.
Until this application no potash had been used in the fertilizers.
The amount given was based upon 1/4-pound of actual potash for
each tree unit, with this amount increased in the same manner as
the other elements were increased at this and the spring
Until 1919 little cultivation had been given the grove in recent
years. In the spring of 1919 the grove was plowed and harrowed
at intervals until the rainy season began, at which time a volun-
teer cover crop growth was allowed to develop.

No quantitative measure of the trees or of the amount of fruit
borne has thus far been obtained in this grove. As a whole the
trees have made a satisfactory growth, and are making full tops
with much fruit wood. In the spring of 1918 the trees set a crop
of fruit that harvested between 3,000 and 4,000 boxes of fruit
from more than 5,000 bearing and non-bearing trees. In the
spring of 1919 a heavy bloom was set that promises a crop that
will greatly exceed 5,000 boxes.
During the fall of 1919 10 trees of uniform size will be selected
from each plot for making a close study for differences in growth
and yield that may be developed by the various sources of phos-
phoric acid used. At the present time no differences are evident


Florida Agricultural Experiment Station

between the trees in the plots receiving the different fertilizer

These experiments with bearing trees are a continuation of
those described briefly in the Annual Reports for 1917 and 1918.
They are being conducted to study the influence of fertilizers,
containing the same sources but different amounts of phosphoric
acid and potash, upon the growth and fruit production of seedling
orange trees, three different varieties of budded orange trees and
grapefruit trees of unknown variety. The experiments were
begun in 1915. The different amounts of these elements contained
in the complete fertilizer formulas were:
6% phosphoric acid................ ...................................... 6% potash
2% ................... .... ..................... 6%
12% ........................................... .. 6%
6% ........................................................ 2%
6% ..... .......................................... 12%
The materials used in making the fertilizers were nitrate of
soda, sulphate of ammonia, dissolved bone black, steamed bone
and sulphate of potash. Three applications of fertilizer have
been given the trees regularly every year. The amount applied
is varied according to the size of the tree.
Records have been kept of the amount of fruit borne by each
tree in the groves at Tampa and at Sutherland. The records at
Sutherland are incomplete, however, owing to the fact that much
fruit was lost on account of the freeze of 1917 and of a severe
storm in the fall of 1918.
No gross differences have developed in the trees or in the fruit
of either grove to indicate that any amount supplied is superior
to any other. The obtaining of differences, however, is probably
complicated by the fact that considerable quantities of phosphoric
acid and potash were doubtless stored in the soil from applications
of complete fertilizers made previous to the time the experiment
was started.

These experiments are a continuation of those started in 1917
and reported in brief in the Annual Report of the Station for 1918


Annual Report, 1919

on page 52R. They are the same as those with bearing trees,
excepting that more varied amounts of phosphoric acid and
potash are used.
Plot IAmmonia I Available Phosphoric Acid I Potash
1 4% 0 0% 51 5
2 4% 0% 4%
3 4: 4 7 3%
4 4'Y 0c 2%
5 4'. 0% 1%
6 45 0% 0%
7 4% 2 i 4%
8 4% 2' i 3%
9 4 29 2%
10 4% 2% 1%
11 4% 2% 0%
12 4 4'' 3%
13 4 7< 4% 2%
14 4- 4% 1%
15 4% i 4% 0%
16 4% 6% 2%
17 4% 6% 1%
18 4% 6% 0%
19 4% 8% 1%
20 4% 8% 7 0%

The experiment is conducted in duplicate. In one experiment
the sources of ammonia are sulphate of ammonia and steamed
bone, whereas in the other they are nitrate of soda and steamed
bone. The experiments were begun in 1917 with trees that were
planted just previous to the freeze of February 1, 1917. This
freeze killed some of the trees entirely and a considerable number
of others were killed back to the top of the banks of soil that had
been thrown up about them to protect them from cold. Thus a
new top was made by these from a sprout putting out from the
trunk below the top of the bank.
Measurements were made of the diameters of the trunks six
inches above the bud union in September, 1917, August, 1918, and
June, 1919. In the cases where sprouts were put out from the
scion, not far from the bud union, the measurement was made at
a point on the sprout 6 inches above its union with the scion.
In August, 1918, when a second measurement was made, a num-
ber of trees had died, and these, with some backward ones, had
been replaced by new trees from the nursery. These were then
only first measurements.
These conditions, coupled with the fact that the number of


Florida Agricultural Experiment Station

trees included in a plot was rather small, complicates the results
as interpreted by the measurements and makes conclusions
Table 11 shows the average increase in diameter per tree made
b.v the trees in the different plots in the two experiments. This
increase is that made between September, 1917, and June, 1919.
The measurements include those of the sprouts as well as those
of the original trunks.

Plots ......6..............ij _11 2 4 81 9110 11712113114115 16il 718119120
With nilrate uf mda-I12 161111110J1016 .15114118113 1216116114118 18|15116114
With sulphate of I -\-
ammonia...... ..1818 22 22 23 1 1 81819 19116113 1214111 9111 9
The trees have made a good thrifty growth, but show little
relationship to the amounts of the different food elements applied.
The trees in the sulphate of ammonia experiment have made a
better growth than those in the other experiment. This may be
due to the fact that, thru a misunderstanding, a crop of cabbage
to which a complete cabbage fertilizer was applied was planted
between the trees in this experiment in the spring of 1918.


Annual Report, 1919


P. H. Rolfs, Director:
SIR: I submit the following report of the plant pathologist for
the fiscal year ending June 30, 1919.
Plant Pathologist.

But little progress was made last season in the line of research
work relating to citrus diseases, and a greater part of the field
experiments connected with this work were temporarily sus-
pended. The absence of qualified laboratory assistance was a
handicap to the work and the demands on the pathologist's time
for information concerning the diseases of the more staple crops
prevented more than limited field observations on the citrus
diseases under study.

One of the most important lines of work for the year has been
projects on avocado diseases. This material will soon be published
in bulletin form, hence it is not necessary to incorporate it here.

A large acreage of castor beans was planted in the state dur-
ing the year as a war emergency crop. Little was known con-
cerning the diseases and enemies of this crop, especially under
Florida conditions. The castor bean plant was claimed to be free
from all diseases and insect pests, but the experiences of last
season would lead to different conclusions.
The following diseases were observed on the castor bean during
the season:
WILT (Baccillus solanacearum) is a bacterial disease similar to
that of tomatoes and potatoes. It appeared early in the season,
affecting the young seedling plants. Individual fields had
from 1 to 10 percent of the plants killed by wilt. The disease
appeared to be more or less general in distribution, except along
the lower east coast regions.
LEAF SPOT (BacciUus sp.) is a bacterial disease similar in gen-


Florida Agricultural Experiment Station

eral appearance to angular leaf spot of cotton. It was more or
less prevalent during the early part of the season.
LEAF SPOTS (Cercospora sp.) and (Macrosporium sp.) are two
distinct types of spotting found more or less generally distrib-
uted, but apparently of little economic importance.

Gray mold (Botrytis sp.) is a new disease and one of the most
serious to the castor bean in Florida. The chief injury results
from attacks on the fruit and flower spikes, causing a rapid decay
of the same. The disease was widespread and destroyed from 50
to 90 percent of the crop in many fields. It probably appeared in
every castor bean field in the state.
In the early part of August a fungous disease was discovered
attacking the fruit spikes of the castor bean plant. Specimens of
this disease were first brought to the writer's attention thru the
State Plant Board.
A fungus was found associated with the diseased spikes that
appeared to be a species of Botrytis. Specimens of the disease
were sent to Mrs. F. W. Patterson, Bureau of Plant Industry,
United States Department of Agriculture, who reported the
fungus as an undescribed species of Botrytis.
The disease was soon reported from many localities as causing
serious injury, and from the rapidity with which it spread and
developed the greater part of the castor bean crop in the state
was seriously threatened.
In Press Bulletin 296 this disease was first described and
referred to as gray mold. Control measures were also suggested
which appeared practical.
The fungus causing this disease was easily isolated from
infected material and grew well under laboratory conditions,
producing spores and sclerotia abundantly.
The pathogenicity of the fungus was proved by inoculations.
Pure strains of the Botrytis were used in the inoculations, and
spores or mycelium of the fungus produced the characteristic
diseased condition when brought into contact with healthy fruit
or flower spikes, and proper moisture conditions were main-
Moisture is an important factor in the spread and development
of the disease as was noted by its rapid progress during rainy
periods. Practically every fruit and flower spike on a castor bean


Annual Report, 1919

plant infected with the disease would be completely ruined during
a rainy period of two or three days. It was observed that all
flower spikes that appeared during the rainy season were more
or less affected, the majority producing no fruits.
Fruit spikes that were nearly mature were rarely attacked by
the fungus, but all stages of development below this were highly
susceptible to the diseases.
The fungus may attack any part of the plant above ground, but
develops more rapidly and is more destructive on the immature
fruit and flower parts.
Sclerotia frequently developed in abundance on infected
material that had been collected and kept for a few days under
moist conditions. Later in the season sclerotia developed in the
infected areas on the stems of plants.
The gray mold proved to be one of the most serious troubles of
the castor bean in Florida. In many cases from 50 to 90 percent
of the crop was lost thru the attack of this Botrytis.
The disease was also noted on the ornamental castor bean,
Palma christi, which is common in many parts of the state. This
variety, however, shows much greater resistance to the disease
than a majority of the commercial varieties that were planted
during the season.

The most striking feature of this disease is the grayish-webby
growth formed on the affected fruit spikes. Infected spikes are
enveloped by a thick cottony mass of aerial mycelia and sporo-
phores, more or less powdery in appearance as the result of the
abundant spore production. In well-developed cases, affecting
the more mature fruit spikes, from half to the entire head may be
covered with the fungus. The disease may start at a single point
in the spike, but spreads rapidly under moist conditions, envel-
oping the entire spike. Any part of the spike may be subject to
attack. The affected part soon dies, turns brown, and later
becomes covered with the grayish aerial growth.
The first appearance of the disease is marked by a dark colored
spot or stain. This spotting may appear on the stem of the fruit
spike, on the pods or pod stems. The affected tissue is found to
be rotted and watery. The aerial fungous growth is visible at
this stage and the remainder of the spike appears green and
normal. Three or four days later a fourth or a half of the affected


Florida Agricultural Experiment Station

portion may be enveloped with a grayish powdery growth, and all
parts covered by the fungus are killed.
The fungus attacks the stem of the plant and occasionally spots
are observed on the leaves. In these cases there is usually an
absence of the mass of aerial growth, and the affected tissue
becomes brown and dry.
Time has not permitted a detailed study of this Botrytis, such
as would warrant a technical description at this time. This part
of the work the writer has left to the Bureau of Plant Industry,
United States Department of Agriculture.

Gray mold was evidently introduced into the state on seed sup-
plied for planting. This is indicated by the wide distribution and
general prevalence of the diseases in the state. There were prob-
ably few fields of castor beans planted in Florida that did not
show more or less gray mold.

Suspecting the seed as a carrier of the disease, attention was
directed to a study of the seed that had been used in planting.
Samples of seed were obtained from several farmers who had
planted castor beans, and, thru the aid of the State Plant Board,
15 bushels in one lot were made available for testing.
Liberal samples were taken from each lot of bean seed and
separated into four groups. The first group contained only the
sound healthy seed, the second discolored and imperfect seed, the
third group contained seed enclosed in part of the hull, and the
fourth trash sifted out of the seed. This trash was made up of
small pieces of hulls, broken beans, soil grains, small stones, etc.
Tests were made from each of the different groups to determine
the presence of the fungus Botrytis that had been previously
isolated from diseased spikes affected with gray mold.
It was found that if diseased material containing the fungus
was placed in sterilized moist soil and lightly covered the Botrytis
soon developed a profuse aerial growth, by which it was easily
recognized. This method was used for detecting the fungus in
the samples of suspected seed.
The samples of trash were tested by mixing small amounts of
this with sterilized moist soil in petri dishes and germinating this
mixture at room temperature for from five to seven days. Trash

Annual Report, 1919

from 10 different samples was tested in this manner and the
Botrytis fungus was obtained from four.
The group containing seed enclosed in part of the hull was
tested in a similar manner, except that sterilized soil in test tubes
was used. A single seed was inserted in each tube and slightly
covered with the soil. From 10 to 20 seed were tested at one time
and several tests were made from each of the different samples.
Fourteen different samples were tested and the Botrytis fungus
was identified in six of these. The group containing discolored
and imperfect seed was tested in the same manner and two out of
12 samples showed the presence of this Botrytis. The fungus
was not found associated with the healthy seed in the few tests
made with this group.
There are three possible ways that this Botrytis may be dis-
tributed with the seed: First, by means of the spores adhering to
the surfaces of the seed coat, hulls and trash particles mixed with
the seed; second, by internal mycelium within the seed that has
been killed by the fungus; and, third, by means of the sclerotial
bodies formed on the parts of hulls and frequently on the seed
coats of the bean. The sclerotial bodies would appear to be a
more common means of dissemination.
If castor beans are grown commercially in Florida in the
future, the danger of planting seed infected with this Botrtyis
should be fully considered. A single castor bean plant infected
with Botrytis would be sufficient to endanger the loss of the
bigger part of the crop from that field. The rapidity with which
the disease develops and spreads makes it one to be avoided under
all circumstances.
Early maturing varieties may be grown without much danger
of loss, but those that produce the larger part of their fruit spikes
during the rainy season will be found wholly unprofitable where
the gray mold is present.
Remedial measures after the disease appears in the field are
rather hopeless.

BLOSSOM-END ROT (Alternaria citri) of citrus was unusually
prevalent this season in several localities, and losses were
reported in individual cases ranging from 2 to 10 percent. This
is the first time in the writer's experience that the disease has
been prevalent enough in the state to attract more than passing
attention. The unusual occurrence of this trouble is not attributed


36R Florida Agricultural Experiment Station

alone to favorable climatic conditions prevailing at the time, but
more likely to the condition of the fruits and their susceptibility
to attack.
In a large percentage of the specimens examined for this dis-
ease, the fruits showed imperfections at the blossom end thru
which the fungus entered.
BLUE MOLD DECAY (Penicillium italicium) and (P. digatatum)
caused a large percentage of loss of fruit during the season.
Weather conditions were ideal for the development and spread
of the fungus, and careless handling of the fruit, as a result of
inexperienced labor that had to be employed, greatly increased
the amount of decay that would normally have occurred.

Annual Report, 1919


P. H. Rolfs, Director:
SIR: I submit the following report of the associate plant path-
ologist for the fiscal year ending June 30, 1919.
Associate Plant Pathologist.

The work with this disease consisted mainly in some field obser-
vations and experiments, tho some attention was also given to a
continuation of the laboratory and field work outlined in the
preceding report.

Potato tubers affected with bacterial blight exhibit the same
external symptoms, "sore eye" or "sleepy eye," as those reported
from Australia (see Smith, E. F., Bacteria in relation to plant
diseases, 3:208, fig. 114, 1914), namely, an abnormal develop-
ment of lenticels and sticking of soil particles to the "eyes" of
diseased potato tubers. The tubers were produced by plants
which showed distinct and typical symptoms of bacterial blight
(a sudden wilting of the tops, discoloration of fibro-vascular
bundles and exudation of dirty-white masses of bacteria from the
stems on cutting them across.) These tubers also showed typical
internal symptoms of the bacterial blight as caused by B. solana-
cearum, E. F. Smith. The writer made several series of cultures
from these and other similarly affected tubers, and in every case
obtained pure cultures of bacteria which in gross cultural char-
acters are identical with B. solanacearutm. Finally it may be
added that when potato tubers showing abnormal lenticels and
"leaky eyes" were used as soil inoculation material in flats in
which young tomato plants were growing the latter, in due time,
also showed symptoms of blight typical of that caused by B.
solanacearum. From these blighted tomato plants the bacteria
were easily, and in every case, reisolated. Thus there seems to be
no room left for doubt in regard to the identity of the disease
reported from Australia with the one so well known in this coun-
try and caused by B. solanacearum.


Florida Agricultural Experiment Station

These external symptoms of the blight give a definite basis for
culling out potato tubers before packing or storing them and in
that way are of considerable value to the growers and dealers.
In concluding this discussion of the external symptoms of
potato tubers affected with the blight it should be stated (1) that
not all tubers affected with this disease show prominent develop-
ment of lenticels, (2) that some tubers may show prominent
development of lenticels without being affected with the disease,
and, (3) that the slimy rot, with offensive odor, probably is not
caused directly by B. solanacearum, altho the latter is most com-
monly accompanied by such rot.
It is a common knowledge among potato growers here that very
often an old potato field is practically or even entirely free from
bacterial blight, while the fields more or less recently cleared
may at the same time be severely affected with the disease. It is
stated, for instance, that in the Hastings district the blight was
at first very common and severe, while now, after some 15 or 20
years of a continuous cultivation of the fields to Irish potatoes, it
has practically disappeared. Observations of the writer fully
support the above statement, tho it may be added here that there
are some old fields, outside of the Hastings district, which still
show a considerable amount of blight. It is evident that during
prolonged cultivation and under certain conditions some change
or changes are taking place that check development of the blight.
Among the factors that might have brought about these changes
are possibly the following: Commercial fertilizers, decrease in
humus and continuous cultivation. The latter undoubtedly affects
physical and biological conditions of the soil. It seemed to the
writer that the first-named possible factor should be tried out in
its effect on the blight.
The other observation of importance in connection with natural
occurrence of the blight is that the disease so far has not been
observed on Florida lime soils. These soils are common on the
lower east coast, especially in Dade County. On such soils no
bacterial blight has been observed by the writer. It may be added
here also that, according to Dr. I. Jagger, who last year made in
this state a fairly thoro survey of castor-bean blight, caused also
by B. solanacearum, in no case has any blight been found on the
lower east coast and at the same time it has been found more or
less common in the other parts of the state where the blight of
tomatoes and potatoes is also common.


Annual Report, 1919

In field experiments an attempt was made to test the effect of
the common ingredients of the standard commercial fertilizers
and of lime on bacterial blight of Irish potatoes. A field, which,
during the preceding year showed a great deal of the blight, was
selected for these experiments. According to Dr. R. Hesler, 75
percent of the plants were infected. The field is on B. G. Benson's
farm, West Tocoi, Florida. The layout of the experiments in this
field and the treatment of different plots, with the number of
blighted plants in each plot, are given in Table 12. The blighted
plants were counted when the plants were fully developed and
good size tubers produced, which was about three weeks before
they were dug.
Crushed Lime- Acid Phosphate- Sulphate of Potash-
Blighted plants..... 53 Blighted plants........ 68 Blighted plants........ 74
Acid Phosphate- Nitrate of Soda- 'Acid Phosphate-
Blighted plants........ 60 Blighted plants........ 75 Blighted plants ...... 35
Sulphate of Potash- Crushed Lime- Nitrate of Soda-
Blighted plants........ 48 Blighted plants........ 44 Blighted plants........ 19
Nitrate of Soda- Sulphate of Potash- Crushed Lime
Blighted plant&.-_ 6 Blighted plants........ 46 Blighted plants-...... 10

The amounts per acre of each of the substances used in these
experiments were as follows: Crushed lime, 12 tons; acid phos-
phate, 1 ton; sulphate of potash, 1/2 ton, and nitrate of soda, 14
ton. All these substances were applied broadcast shortly before
planting the potatoes. Neither of the treatments was injurious
to the crop, tho this was not ascertained by measurement. The
field was treated and cultivated according to the general practice
on the farm. Each plot contained five rows (one row serving as
a buffer) 105 feet long; at the ends of the plots 12-foot buffer
space was left.
The counts of blighted plants in these plots show plainly that
none of the treatments checked the blight to any noticeable extent.

The disease has been reported from this Station by 0. F.
Burger (see Fla. Exp. Sta. Bul. 121), who considered that the
same bacteria which causes cucumber fruit rot is also responsible
for a white, angular leaf spot of the same plant. Later there
appeared another work on the leaf spot of cucumber (see Smith,
E. F., and Bryan, May K., Angular leaf spot of cucumbers, Jour.


Florida Agricultural Experiment Station

Agr. Res. 5, No. 11, 1915) in which a statement is made that "no
direct connection has been found between the leaf-spot and the
soft-rots of the fruit" (1. c., p. 475). Last spring the writer had
an opportunity to observe both of these diseases in their typical
form, and to isolate and do some inoculation work with the bac-
teria causing these diseases. The result of inoculation with the
bacteria isolated from rotted cucumber fruit was a rot which was
neither rapidly developing nor a characteristic "soft" rot.

The stem-rot of corn is manifested by decaying of corn stems.
The rot always starts near the level of the soil, sometimes just
above or just below, and finally results in breaking the stem at
the point of infection. Fully grown plants, just before their
tasseling, were observed to be seriously attacked by the disease,
in some instances as much as 30 percent being affected. Early
this summer the disease was observed and reported from central
and western Florida. From a close examination of its symptoms,
and from microscopic and cultural studies of the diseased
material, it appears that this stem-rot of corn quite corresponds
to the so-called damping-off of young plants in seedbeds and is
probably caused by a species of Pythium and by some Fusaria
(?). Pure cultures of Pythium sp. were isolated from several
specimens of corn stem-rot, while in other cases several different
species of Fusaria were isolated from the affected plants.

The practice of spraying Irish potatoes to control late blight is
pretty well established in the greater part of the country and
hardly needs any further experimentation, except to determine
certain details. In this state, tho, the situation was by no means
clear; first, because of comparatively dry weather during the
main potato-growing season in the spring; and, second, because
only early varieties of potatoes are grown here. However, there
was no doubt that during a season especially favorable to the dis-
ease, spraying with Bordeaux mixture was an effective and profit-
able operation. The size of the plants during the first spraying,
March 14 and 15, the yield for each grade of potatoes of each plot,
and the averages and totals for each plot and field, are given in
Tables 13 and 14. The tables were made by Mr. Leonard, on
whose farm these experiments were conducted.


Annual Report, 1919


I No. 1 I Primes INo. 3 No. 4 Total
Plot No. 1- I
Sprayed ........... 161 lbs. 43 lbs. 12 Ibs. 4 lbs. 220 lbs.
Unsprayed ........ 97 lbs. 51 lbs. 10 lbs. 6 lbs. 164 lbs.
Plot No. 2-
Sprayed ........... 162 lbs. 43 Ibs. 10 lbs. 6 lbs. 221 lbs.
Unsprayed ........ 107 lbs. 53 lbs. 14 lbs. 2 Ibs. 176 Ibs.
Plot No. 3
Sprayed .......... 158 lbs. 59 lbs. 14 lbs. 5 lbs. 236 Ibs.
Unsprayed ...... I 142 lbs. 54 Ibs. 11 Ibs. 7 lbs. 214 Ibs.

(Test taken from two rows in each plot, each approximately 200 feet long.)
Sprayed plots show gain No. 1 (+) 135 lbs.
Unsprayed plots slow gain Primes ( -) 13 Ibs.
Sprayed plots show gain No. 3 (+) 1 lb.
No difference in weight on No. 4.
Sprayed plots show total gain (+) 123 lbs.
Increase in yield, sprayed over unsprayed, 24.4 percent.

SNo. 1 I Primes :No. 3 No. 4 Total
Plot No. 4-
Sprayed ........... 212 lbs. I 58 lbs. I 15 Ibs. 7 lbs. 292 lbs.
Unsprayed ...... 170 Ibs. 40 lbs. 13 lbs. 6 lbs. ..229 lbs.
Plot No. 5- I
Sprayed ........... 326 Ibs. 40 lbs. I 14 lbs. 8 lbs. 388 lbs.
Unsprayed ........ 156 lbs. 52 lbs. 16 lbs. 9 lbs. 233 lbs.
Plot No. 6-
Sprayed ........I 237 lbs. I 44 lbs. I 12 Ibs. 10 lbs. 303 lbs.
Unsprayed ........l 185 lbs. I 54 Ibs. 19 lbs. I 10 lbs. 268 lbs...

(Test taken from two rows in each plot, each approximately 200 feet long.)
Sprayed plots show gain in No. 1 (+) 264 lbs.
Unsprayed plots show gain in Primes (-) 4 lbs.
Unsprayed plots show gain in No. 3 (-) 7 Ibs.
No difference in weight on No. 4.
Sprayed plots show total gain (+) 253 lbs.
Increase in yield of sprayed over unsprayed, 34.6 percent.

As can be easily found from Table 13, the total gain in No. 1
potatoes in favor of sprayed plots, as compared with the
unsprayed, is 135 pounds, or 39 per cent; and for the second field
264 pounds, or 51.6 percent. This makes an average gain in the
two fields in No. 1 potatoes in favor of the spraying equal to over
45 percent of the total No. 1 potatoes in both fields. According to
the data at hand, kindly supplied by Mr. Leonard, the first field
yielded this season an average of 31 barrels per acre, while the
second yielded 43 barrels, making an average for both fields of


Florida Agricultural Experiment Station

37 barrels per acre. If these same fields had not been sprayed,
then it would naturally be expected that the yield would have been
at least as much reduced as it was in the case of the unsprayed
check plots-that is, about 20 percent for the first field and about
26 percent for the second field, or about 23 percent of the crop
would have been lost if the potatoes had not been sprayed. This
would amount to over 8.5 barrels per acre, or over 340 barrels for
the 40 acres in the two fields. It may be assumed that the price
of the potatoes f. o. b., without the container, was at least $6.50
per barrel. In that case the spraying of the two fields saved at
least $2,210. The cost of the spraying of the 40 acres (five times
one field and seven times the other) was about $286.

The disease has been referred to in preceding reports (see Fla.
Agr. Exp. Sta. Ann. Repts., 1916, pp. 93R-98R, and 1917, pp. 85R-
86R) as being caused primarily by the root-knot nematodes, prob-
ably followed by certain rot-producing fungi. During 1916-17
the weather conditions were extremely unfavorable to pineapple
culture in the main district, St. Lucie County. However, the con-
ditions of the following two years were such as to indicate that
the culture may revive again. Therefore, some further work on
the wilt was considered desirable. In view of this, the writer
suggested to the local pineapple growers, thru the county agricul-
tural demonstration agent, A. Warren, the necessity of conduct-
ing some cooperative experiments looking toward practical
methods to control the nematodes and, in that way, of the wilt.
To begin with only one method, that of thoro and continuous soil
cultivation, was suggested for the experiments.


Annual Report, 1919


P. H. Rolfs, Director:
SIR: I submit the following report of the chemist for the fiscal
year ending June 30, 1919.

The cooperative fertilizer experiments which have been carried
on for the last 10 years in Lake County were closed out January 1,
1919. A full report of the work will be published shortly as a
bulletin of the Station.
The trees have never borne a full crop of fruit as trees of their
age should have done, owing to the prevalence of dieback at
various times and to other causes beyond the control of grove
management. It has, therefore, been impossible to carry on any
investigations on that part of the project having to do with a
study of the yields and quality of the fruit as affected by the
various fertilizers used. However, while this has been a great
disappointment, much valuable information has been obtained
concerning the effects of the fertilizers and various cultural treat-
ments upon the growth of the citrus tree, and upon the composi-
tion of the soil. Much light has been thrown upon the questions
of the fixation of phosphoric acid and potash by the type of soil
used, and the form in which these elements are retained by the
soil. It is believed that the data obtained give information which
may be applied with confidence to similar soils over the state.
Much of the work which has been done during the preceding
year is being reserved for a future publication under the heading
of "Citrus Fertilizing Experiments."

The drainage water from the eight soil tanks has been collected
and analyzed as usual, and is reported in tables 15'and 16.
The rainfall during the period represented was under normal,
several dry periods of considerable length occurring. The injury
of the trees by the freeze of February, 1917, is still apparent in
the increased amount of plant food appearing in the drainage.
This injury, by cutting down the amount of leaf sur-



Florida Agricultural Experiment Station

Tank 1
ITotal I | ~
Date_ NH_ ON I Cl SO. IHCO. K,0 CaO MgO
Aug. 8, 1917....... 92 101 1 382 13.2 159 140 10.4
Aug. 23, ........ .31 125 35 397 511 107 148 12.1
Oct. 5, ... .224 74 27 530 10.1 75 121 17.3
Mar. 27, 1918.......... 9 125 29 475 12.3 45 104 21.6
Sept. 6, .......... 17 67 12 391 4.6 89 138 14.7
Tank 2
Aug. 3, 1917. ....... .78 139 | 36 386 19.2 179 80 7.1
Aug. 23, ....41 147 31 315 7.5 148 165 11.9
Oct. 5, .19 69 18 290 11.0 98 101 19.8
Mar. 27, 1918.......... 21 119 80 475 4.7 105 157 14.6
Sept. 6, .......... .14 78 21 201 2.1 98 131 22.1
Tank 3
Aug. 3, 1917.......... 19 159 39 154 27.3 142 254 6.9
Aug. 23, .. 17 131 27 276 29.1 119 44.4 7.1
Oct. 5, ....... .12 107 29 375 32.0 87 75.1 15.2
Mar. 27, 1918...... .10 161 32 221 224 59 54.2 12A
Sept. 6, .......... .09 65 19 189 37.1 63 37.5 11.7
Tank 4
Aug. 3, 1917. ....... .27 79 21 359 38.2 132 169 12.2
Aug. 23, .......... .16 91 16 376 25.7 105 172 12.1
Oct. 5, ".......... .21 60 27 291 31A 87 198 23.6
Mar. 27, 1918.......... .12 41 19 301 19.7 76 131 19.8
Sept. 6, ......... .16 22 14 245 25.1 45 122 14.3

face, has reduced the amount of water lost by evaporation and
more of it has appeared in the drainage, thus leaching out more
of the fertilizers. It will be noted that with both sets of tanks
the loss is larger than for several years past. Both nitrogen and
potash have been lost in notably large amounts. The lime in the
drainage from Tank 8 is still increasing. This tank receives
ground limestone in addition to the fertilizer.

In the spring of 1918 samples of soil were received from the
plots in the potato experiments conducted near Hastings by the
Department of Plant Physiology. These samples, 22 in number,
have now been analyzed for nitrogen, phosphoric acid and total
potash by the fusion method.

Annual Report, 1919

Tank 5

Aug. 3, 1917 .........
Aug. 23, ........
Oct. 5, .........
Mar. 27, 1918 .......
Sept. 6, .....
Dec. 6, ..

I I Total I I I |
.11 9.4 2.1 4.7 22.2 2.3 14.2 7.0
.07 11.2 3.4 4.6 14.2 1.4 12.8 5.7
.09 7.1 1 4.2 3.7 12.4 3.0 15.2 6.1
I .04 4.3 2.9 5.1.. 14.6 2.1 1L4 8.4
..07 7.2 3.4 4.2 1 17.3 1.9 17.3 4.3
.05 6.9 4.8 3.9 I 11.4 2.4 12.9 7.9

Tank 6
Aug. 3, 1917....... .17 145 14.1 112 27.0 1 75 45.4 10.6
Aug. 23, ....... .13 109 12.7 96 21.6 61 35.5 8.3
Oct. 5, .......... .05 97 9.7 147 25.4 52 74U1 15.4
Mar. 27, 1918.......... .07 107 11.2 121 31.2 ,68 67.0 18.6
Sept. 6, "...... .09 61 112.9 189 22.4 49 312 23.4
Dec. 6, .12 9 1 9.1 198 253 72 75.0 25.9
Tank 7
Aug. 3, 1917.......... .34 139 I 12.1 57 19.4 65 39JO 13.1
Aug. 23, "........ .15 151 15.9 37 26.7 41 48.2 13.0
Oct. 5, "......... 13 107 11.2 28 20.9 32 271 17.3
Mar. 27, 1918.......... .09 99 19.2 39 8.7 51 39.3 15.9
Sept. 6, .......... .11 115 14.1 67 17.3 43 4140 11.6
Dec. 6, .......... .07 127 8.1 89 12.8 35 50.0 19.8
Tank 8
Aug. 3, 1917-...... .31 156 14.1 217 23.4 57 I 92.9 15.4
Aug. 23," .......... .11 117 9.2 169 18.2 32 76.7 14.5
Oct. 5, ......... .05 97 13.5 187 12.6 41 1512 25.7
Mar. 27, 1918.......... .09 89 12.1 251 17.5 39 174.3 34.9
Sept. 6, ......... .11 111 7.9 204 22.4 45 121.0 27.3
Dec. 6,07 121 13.2 299 14.3 50 1441 30.4


Florida Agricultural Experiment Station


P. H. Rolfs, Director.
Srm: I submit the following report of the assistant agronomist
for the fiscal year ending June 30, 1919.
Assistant Agronomist.


The 10 varieties of cotton used in the variety test of last year
were used again this year. The plots were 3/50 of an acre in size
and were repeated three times in 1917 and four times in 1918.
The following table gives the average yield of seed cotton per acre
and the percentage of the total cotton picked from the first pick-
ings during 1917-18.

1 1917 || 1918
I Pounds Percentage II Pounds Percentage
Variety I per acre ,1stpicking II per acre Istpicking
Cleveland Big Boll........... 463 30 95 46
Mexican Big Boll............. 400 56 110 I 51
Hartaville No. 9................ 478 42 88 42
Hartsville No. 11.............. 500 25 62 34
Cook's Improved ............. 726 48 153 54
Webber's No. 49............. 532 43 116 45
Trice ................................... 615 72 126 51
Lone Star .................. 691 51 83 36
Durango ............................. 675 56 52 59
Sosnowaki ........................ 336 35 25 11

It should be stated that the soil used during the two years was
practically of the same productivity, and that the 1918 crop had
the advantage of two stalks per hill. The plantings each year
were in rows 4 feet 4 inches apart by 2 feet in the drill. The
decreased yield in 1918 would seem to be due to the boll weevil.
The boll weevil did little damage during 1917.

Experiments were started during the spring of 1918 with
peanuts to determine the values of phosphates, limes and dried
blood as fertilizer for peanuts.


Annual Report, 1919



Av. perI
acre ........

TNo Limeston
Bushels W<
Per acre* of
42.8 1,
38.0 1,
42.5 1
35.7 1,
44.7 1,
51.3 1
45.7 1
51.8 1
56.4 1
57.3 1,
50.2 1,
49.8 1
49.8 1
55.3 1,
42.6 1,
45.1 1
60.3 1,
60.3 1,
61.8 1,
49.5 1,
51.6 1,
60.3 1,
52.5 1,
47.1 1,
46.1 1
49.8 1,

48.2 1,

*22 pounds nuts per bushel.
C, Check, no fertilizers.
SP, Soft phosphate (Calci.) 1,000 pounds to the acre.
HP, Hard phosphate (Natursown) 1,000 pounds to the acre.
AP, Acid phosphate (16%) 500 pounds to the acre.
N, Dried blood (14%) 100 pounds to the acre.
HL, Hydrated lime 500 pounds to the acre.
Limestone was applied at the rate of 2,000 pounds to the acre to half of
each plot.
SPN, Soft phosphate 1,000 pounds to the acre, and dried blood 100 pounds
to the acre.
HPN, Hard phosphate 1,000 pounds to the acre and dried blood 100 pounds
to the acre.
APN, Acid phosphate 500 pounds to the acre and dried blood 100 pounds
to the acre.

e I I Limestone
eight Fertilizer [ Bushels [ Weight
hay treatment per acre of hay
,292 C 60.0 I 1,156
,292 SP 50.1 1,360
,428 HP 54.1 1,360
782 AP 51.0 1,166
,190 C 40.2 1,020
,326 N 41.5 1,020
,258 HL 44.8 1,190
,564 SPN 49.9 1,190
,564 C 49.8 1,258
,802 HPN 56.3 1,326
,666 APN 45.6 1,258
,360 SP 53.5 1,224
,156 C 49.0 1,156
,156 HP 52.5 1,156
,428 AP 59.0 1,156
,292 N 59.3 1,258
,564 C 43.3 1,156
,258 C '56.4 1,224
,598 HL 60. 1,530
,292 SPN 69:1 1,360
,156 HPN 53.3 1,054
,224 C 52.7 1,054
292 APN 54.7 1,190
,088 SP 50.0 986
088 HP 53.3 1,156
918 C 51.5 1,020
,088 AP 51.5 1,224
,224 N 59.1 1,190
884 HL 43.7 1,020
850 C 43.7 680
918 SPN 43.7 850
850 HPN 60.7 850
850 APN 60.7 816
748 C 44.8 748

.219 52.0 1.122

I t

Florida Agricultural Experiment Station

The plan calls for a two-year rotation in which the peanuts are
to receive the fertilizers and be followed with corn and velvet
beans planted together without additional fertilizer treatment.
The residual effect of the fertilizers on the corn will be kept.
The plots are approximately 3/50 of an acre in size, being 209
feet long and 121/2 feet wide. Ground limestone was applied to
the north half of the plots at the rate of 2,000 pounds to the acre.
The limestone was sown broadcast and harrowed in about three
weeks before planting. The unlimed half was also harrowed at
the same time.
The fertilizers were applied in the drill just before planting
and each treatment was run in triplicate, as shown in Table 18,
which gives the treatment, also the yield of nuts and hay.
Table 19 shows the averages of the various treatments, there
being 10 checks and three for each of the treatments.
No Limestone I I Limestone I
Bu. per Lbs. hay I Bu. per Lbs. hay \Avg. of fert. tr'tment
acre per acre I Treatment I acre per acre I Nuts I Hay
47.0 1,176 I C (10)* 49.1 1,037 4881 1,117
46.9 1,247 SP ( 3) 51.3 1,190 49.1 1,219
46,1 1,224 HP ( 3) 53.3 1,224 49.7 1,224
44.8 1,099 AP ( 3) 53.8 1,179 49.1 1,139
46.7 1,281 N ( 3) 54.3 1,156 50.0 1,219
52.4 1,247 HL ( 3) 49.6 1,179 51.0 1,213
49.3 1,258 SPN ( 3) 54.2 1,133 51.8 1,196
50M5 1,269 HPN ( 3) 56.8 1,077 53.7 1,173
54.0 1,269 APN ( 3) 53.7 1,088 58.9 1,179
Avg. 48.2 1 1,219 I | 52.0 1,122 50.1 | 1,170

It will be noted that the fertilizer has increased the yield on
the average, but the increase has been generally slight, in no case
sufficient to pay the cost of the treatment. In the summary table
the results are slightly unfavorable to the treatments containing
but a single element, and, therefore, favorable to the double treat-
ments, due to the greater productivity of the check plots on the
second half of the area beginning with plot 18.
The use of lime has uniformly increased the yield. There is an
average increase of 4.7 bushels, due to limestone, and of 5.4
bushels, due to the hydrated lime on the unlimed half. When the
hydrated lime was used in addition to ground limestone the effect

*The figures in the parenthesis represent the number of plots averaged
for each treatment.

Annual Report, 1919 49R

of the lime was decreased, thus indicating that a too heavy appli-
cation of lime might be detrimental.
Corn has been planted on these plots and the residual effect will
be noted during 1919. The experiment is being continued and the
prospects for a good crop are favorable.

An experiment has been started to test the effect of the hard,
soft and super-phosphate, also of potash and dried blood, on sweet

Florida Agricultural Experiment Station


P. H. Rolfs, Director:
Smn: I submit the following report of the entomologist for
the fiscal year ending June 30, 1919.

In the last annual report reference was made to injury to crops
by the use of cyanamid. This cyanamid was admittedly old
material which had been in storage for at least a year. Experi-
ments were carried on to determine if there is a difference
between this old material and fresh material. It was found that
celery would stand much more fresh material than old material.
The plots on which the fresh material was used grew off readily
and continued to thrive and do well, while those on which the
older cyanamid was applied grew off well for about two weeks
and then showed unmistakable signs of burning, except on the
edges of the plot, where there was more or less shade. This ten-
dency of plants in the shade to endure larger doses of cyanamid
is probably due to the greater concentration of poisonous com-
pounds in plants subjected to factors which give greater evapora-
tion from their tissues.

The trials with these compounds were continued in an effort to
determine the minimum amount which would effect a satisfactory
control of the root-knot nematode. Doses ranging from 300 to
1,200 pounds of cyanide to the acre were used. On greenhouse
benches, where there was about 5 inches of soil, apparently com-
plete eradication was obtained by the application of 600 pounds
to the acre, and a material reduction in the number of worms by
300 pounds. In deeper soils 600 pounds did not completely eradi-
cate the worms, but it reduced the number to the point where it
was possible to grow for a year highly susceptible plants on the
It would seem that for the average trucker 600 pounds of
sodium cyanide and 900 pounds of ammonium sulphate to the acre
is the most practical dose. On seedbeds, where expensive crops


Annual Report, 1919

are to be grown, 800 pounds of sodium cyanide and 1,200 pounds
of ammonium sulphate to the acre seems more practical.
On plots where ammonium sulphate alone was used at the rate
of 1,800 pounds or more to the acre, there was a great reduction
in the number of nematodes.

Summer-fallow experiments were continued in the effort to
determine particularly the length of time it should be kept up.
The most effective treatment was to start in June and continue
until the fall crop was planted, generally in October.

VELVET BEAN CATERPILLAR (Anticarsia gemmatilis)
The study of the parasites, predators and preferences of this
insect for different varieties of velvet beans was continued.
The percentage of parasitization among nearly 1,000 pupae,
collected in the fields during the latter part of September and
October, was again only about 1 percent, showing that the per-
centage obtained in other years was not exceptional. Evidently
internal insect parasites are not an appreciable factor in the
control of this insect.

As previously reported (Ann. Rept., 1915), this insect is exter-
minated during the winter in at least northern and central
Florida thru the killing by frost of all the host plants of the larvae
and the inability of the pupae to remain dormant long enough to
tide over the winter. It is evident that the latitude above which
they are exterminated will vary from year to year with the lati-
tude reached by killing frosts. It would also seem that the length
of time between the first killing frost and the last would be impor-
tant, as in the case of the boll weevil near the northern limit of
its distribution. As reported (loc. cit., p. Ivi), caterpillars ma-
turing late may remain in the pupal stage as long as 48 days. If
the time between the first killing frost and the last is no longer
than this, it might be possible for the insect to tide over the win-
ter. The moths issuing from the last fall pupae might find host
plants on which to lay their eggs. It would seem, therefore,
that the latitude to which they are killed back and hence the
date of their reappearance and, other factors being equal, their


52R Florida Agricultural Experiment Station

numbers, during the succeeding summer, should vary according
to the length of the winter, i. e., the time between the first kill-
ing frost and the last-the time when there is no food for the
caterpillars-the starvation period. If the first severe frost
comes early and extends far down the peninsula the insects
should be pushed down so far that they will be slow in reappear-
ing the following year.
The last two years have afforded an excellent opportunity to
test the correctness of this reasoning and to demonstrate the
importance of the winter on the numbers of the caterpillars
during the succeeding summer.
The following minimum temperatures taken from the records
of the United States Weather Bureau at Gainesville are typical of
at least the central parts of the state. All temperatures above 30
have been neglected, for altho all the known host plants of the
caterpillars are sensitive to even a light frost, they often grow
under trees and in other protected places, so that a hard frost is
necessary to kill them all.
AND 1918-19.
1917-18 | 1918-19
N ov. 25........................................... 23
D ec. 10.............................................. 28
Dec. 11.................................. .......... 29
Dec. 14............................ ................. 27
Dec. 30S...................................... ....... 24 Dec. 29................................. ..... .. 26
Dec. 31 ............................ ............ 18
Jan. 1 ............................. ........... 18
Jan. 2............................................ 21
Jan. 4............................................. 24
Jan. 5..... ................... ...... 29 Jan. 5............................................. .... 24
Jan. 8............................ ....... ....... 24
Jan. 9........................................... 29
Jan. 13.................................... ............ 21
Jan. 24............................................ 26
Feb. 5.......-.................................. 29 Feb. 10.............................................. 29

It can readily be seen from the table that during the winter of
1917-18 the period from the first severe frost (23 deg.) to the
last (29 deg.) was 72 days; during 1918-19 only 43 days. If one
counts only temperatures below 29, or even 26, the starvation
period was 60 days during 1917-18 and only 7 during 1918-19. To
these numbers, however, should be added 15 or 20 days to give
such plants as velvet beans and kudzu time to spring up. Unless
the weather is quite warm they will require a longer time. This

Annual Report, 1919

will make the starvation period for 1917-18 at least 87 days; for
1918-19, 58 days. The latter is only 10 days longer than the
longest observed pupation period and the adult moths could easily
live that long. It would seem quite possible then for the species
to have survived last winter (in small numbers, of course) as
far north as Gainesville. It apparently did not do so, but prob-
ably did in a few counties further south.
In comparing the dates of the first arrivals of the moths and the
abundance of the caterpillars during the two seasons one finds a
close correlation.
The moths did not appear at Gainesville until August in 1918.
Altho some fields were considerably damaged, none were entirely
destroyed. On the Station farm for the first time in at least eight
years no poisoning was necessary. On the other hand, in 1919
moths were observed at Gainesville on June 27, nearly a month
earlier than ever before. It would seem that the caterpillars may
be expected this year to at least regain the ground lost during the
winter of 1917-18.
Of course, other factors may more than counteract this effect
of the winter weather. An unusually late or early appearance of
"cholera" could easily obscure the effects of the winter. So could
an increase or decrease in the numbers of the insect's numer-
ous predators. As far as these observations extend, however,
there has not been much variation in these agents of control.
"Cholera" makes its appearance at about the same time each
year and the number of predators-birds, lizards, toads, and
insects-does not vary greatly.
The advantage of being able to predict "bad" or "good" cater-
pillar years is obvious. If an increase is indicated, the farmer
will want to make liberal allowance for a trap crop; to plant early,
using mostly early-maturing varieties; perhaps to reduce his acre-
age, planting other forage crops to replace the velvet beans; or
else to prepare to dust his vines thoroly. If the indications are
for a year of less severe damage, he can plant the varieties that
best suit his needs irrespective of their earliness.


Incidental to the work on Anticarsia, some data have been col-
lected on the minor pests of the vines. These include many species
of jassids, a thrips, red spiders and leaf-tyers, larvae of skipper
butterflies. Altho the damage caused by these minor pests is


Florida Agricultural Experiment Station

barely noticeable on any one vine, it is in the aggregate large and
apparently on the increase. This is particularly true of some of
the larger species of skippers. Legumes are the favorite host
plants of the larvae of most skippers, and one wonders why they
do not infest the velvet bean more than they do. As the years
pass it is quite probable that they will adapt themselves more and
more to this source of food.
A study of material collected about Miami by A. C. Mason, of
the United States Bureau of Entomology, and by members of the
State Plant Board, revealed the fact that two other species of
Frankliniella, in addition to the Florida flower thrips (F. bis-
pinosus, Morgan) are concerned in the injury to citrus in that
region. They are Mason's thrips and the Cuban citrus thrips.

MASON'S THuIPS (F. cephalica nmaoni Watson)
This species is similar in appearance to the Florida flower
thrips, but may be distinguished by the unaided eye or a simple
lens, by its lighter color and the absence of any orange on the
thorax. It averages a little smaller. Under a good microscope it
may be distinguished from the other by a sunken area in the front
part of the head in front of the anterior ocellus which is directed
forward. (For a technical description of the insect, see "Florida
Buggist," Vol. II, No. 3.)
The character of the injury seems to be identical to that of the
Florida flower thrips. The species (F. cephalica crawford), of
which this is a variety, is a subtropical insect found in Mexico and
Texas. A single specimen of Mason's thrips has been found at
Gainesville. Besides citrus, it has been found on beans, blue
beech (Carpinus caroliniana), mango, papaya, avocado, morning
glory and other wild plants.

THE CUBAN CITus THeIPS (F. insularis, Franklin)
This species, hitherto known only from the West Indies, was
found to be quite widespread about Miami. Whether it is native
to the region or recently introduced cannot be definitely stated at
this time. If it is an introduced species, it has been here for some
years, as it was found as far south as Royal Palm Park. How-
ever, careful search by Mr. Mason and members of the State


Annual Report, 1919

Plant Board failed to disclose it on the Keys or in Palm Beach
County. The fact that it is not especially abundant anywhere in
the region would indicate that it is not likely to prove a serious
pest. Nevertheless, the subject needs careful investigation.
This insect is easily told from the Florida flower thrips by its
color, which is dark brown. At Miami, besides citrus, it was col-
lected from Carissa grandiflora and beans. It has also been
reported on many plants in the West Indies.

Since first coming to the state the entomologist has noticed a
certain blight of peanuts characterized by a blackening of the
growing tips, leaves and stems, but not until this year did he
connect the damage with thrips. In April specimens which were
swarming with thrips were sent in from Oldsmar, and later a
severe infestation was located by a member of the Station staff
at Moore Haven. The species responsible for the injury is the
common Florida flower thrips.
The injury is characteristic thrips injury, similar to that
inflicted by the camphor thrips on tender growth or to that on
the peach and pear foliage by this same species when abundant.
The infestation may be controlled by spraying with tobacco
extract and soap. It has been the writer's observation that the
vines usually recover from the injury as soon as the summer
rains bring the thrips under control. The plants usually remain
stunted, however, and the yield is reduced. In case of a severe
infestation spraying will pay well.

This insect seems to be increasing in numbers, especially in
the commercial plantation at Satsuma, where first discovered.
The superintendent of the plantation considers it the determin-
ing factor of the industry. Because of their situation in the
crevice of the bark, the eggs and many of the adults are out of
reach of any insecticide. It is now pretty widely spread over the
state and in Alabama.

THE PUMPKIN BUG (Nezara viridula)
Thoro studies of the life history, parasites and predators of
this insect were completed by Prof. Carl J. Drake, associate pro-


Florida Agricultural Experiment Station

fessor of entomology in the New York School of Forestry at
Syracuse University, who was employed by the Florida Experi-
ment Station for this purpose during four months of the summer
of 1918.
THE COTTON STAINER (Dysdercus saturellus) ON CITRUS
As a result of the spread of the boll weevil into the sea island
cotton region, considerable plantings of cotton were made in the
citrus areas of the state. There was an unusual abundance of
the insects and severe damage was done to citrus in many
In most cases there was no room for doubt about the cotton's
being the source of the bugs that attacked the citrus. In many
cases they were seen crawling and flying from adjacent cotton
fields to citrus. In one case they were migrating in numbers
directly against the wind. It looked as if they had located the
citrus thru the sense of smell. In other cases they were observed
flying into a grove with the wind. In one case the nearest cotton
fields were two miles away.
Contrary to the statement in Hubbard's "Orange Insects,"
these bugs do breed occasionally on oranges. Several colonies of
very young bugs were seen on rotting oranges. Not only were
these too young to have crawled there, but the fact that they
were still collected in a colony showed that they were hatched
there. The eggs of these bugs are laid in masses and the young
are gregarious for some days after hatching, feeding near where
they are hatched. The colony does not move far en masse, and
after the bugs become old enough to scatter they do not again
form colonies of bugs of the same age. There is a marked ten-
dency, especially at night, for all stages, particularly the adults,
to congregate in groups, but these are composed of individuals
of all ages. In the laboratory the bugs were raised to maturity
on oranges.
The character of the injury to citrus is much like that of the
pumpkin bug. The cotton stainer is much more restless, how-
ever, and does not remain for hours with its beak inserted in one
spot as does the pumpkin bug. Its punctures are even more
minute, practically invisible to the unaided eye. The insect
shows the same preference for thin-skinned varieties of citrus,
tangerines being the first choice. For this reason an injured
orange is even more difficult to detect, but' it will, like those
injured by Nezarra, quickly decay. Some of the unusual amount


Annual Report, 1919

of decay suffered by oranges in transit the past winter is
undoubtedly to be charged to this insect.
The insect is more delicate than the pumpkin bug, and a
strong solution of whale-oil soap, 6 or 8 pounds to 50 gallons of
soft water, will kill both adults and young. They are agile, how-
ever, and the man with the nozzle must move quickly or many of
them will escape. The spray gun seems to be about the best
implement to use for this purpose. One grower stated that.a
row of roselle alongside the trees gave complete protection to a
row of tangerine trees. It acted as a trap crop.
This lady-beetle continued to multiply, especially in one grove
near Bradentown. By the fall of 1918 it had commenced to
reduce, appreciably, the numbers of whitefly in the grove. Dur-
ing the winter its numbers diminished somewhat. In northern
Polk County, where also a flourishing colony had become estab-
lished, the decrease during the winter was more marked.
Whether this reduction in numbers is due to the direct action
of the cold or to the scarcity of its preferred food, the eggs of
whiteflies, has not been determined. With the coming of spring
the colony at Bradentown again multiplied and did such efficient
work that spraying was omitted in that part of the grove where
they were most abundant.


The cowpea pod weevil (Chalcodernnus aeneus) severely
attacked adzuki beans on the Station grounds.
During July there occurred thruout a large part of the state
the most severe attack of the fall army worm (Laphygma frugi-
perda) since 1912. As was the case during the more severe
infestations of 1912, the damage was greater in the central and
northern parts of the state. Kissimmee was the most southern
locality reporting an infestation.
The unusually late date (December 29) of the first killing
frost of the season allowed the pigeon pea to fruit abundantly at
Gainesville and afforded an opportunity for studying the insect
pests of the plant. The foliage is, except for a few jassids,
unusually free from insect attacks; but the pods with their con-
tained peas were severely attacked by the corn ear-worm
(Chloiidea obsoleta) and the leaf-footed plant-bug (Lepto-


Florida Agricultural Experiment Station

glossus phyllopus). Both of these insects work on beans and
garden peas in an identical manner. The northern green stink-
bug (Nezara hilaris) attacked the stalks to some extent in the
fall. It is more apt to attack shrubs, while the pumpkin bug is
preeminently an herb-sucking insect. Bumblebees seem to be
the chief agents in pollinating the blossoms.
In April, 1919, the oak-defoliator (Anisota stigma) became
excessively abundant in the vicinity of Seffner. After defoliat-
ing the oaks it attacked corn and melons. This is a common
insect on oaks every spring, but it seldom becomes sufficiently
abundant to do appreciable damage to the trees.
The common blue predaceous bug, Euthyrhynchus floridanus,
was sent in from Polk County, where it was attacking honey
bees. This is usually a very beneficial insect, which does espe-
cially good work against the velvet bean caterpillar.

Cutworms seemed to be particularly attracted to castor beans,
and did much damage. No attempt was made to identify the
species involved.
Beginning at Gainesville as early as May, but not becoming
serious in the fields until July, army worms attacked the leaves.
Three species were chiefly concerned. On the lower east coast,
especially, and in the southern part of the state, generally, the
damage was due to the semi-tropical army worm (Xylomeges
eridania). In the central and northern parts of the state the
closely related and very similar sweet-potato caterpillar (Pro-
denia ornithogalli) was more in evidence. The fall army worm
or grass worm also attacked castor beans to some extent, altho it
infested mostly plants of the grass family. The remedy applied
was the same for all three species, viz., dusting the plants with
lead arsenate. The leaves were also attacked by a number of
small bugs, including the bean leaf-hopper (Empoasci mali) and
other jassids, and the cotton lace-bug (Corythuca gossypii).
The pink corn worm (Batratchetra rileyi) was much in evi-
dence on the spikes. As is usually the case with this caterpillar,
which is commonly found on decaying corn and cotton, it acted
chiefly as a scavenger. It fed largely on the withered staminate
blossoms and on pods infested with the gray mold, and but little
on healthy tissue.
The corn ear-worm (Chloridea obsoleta) attacked the pods to


Annual Report, 1919 59R

a limited extent, eating a hole into them and mining them much
as it does green tomatoes, beans or peas. The army worms also
attacked the pods, but ate off the epidermis instead of mining
Later in the season, October and November, the pods were
commonly attacked by the pumpkin bug (Nezara viridula).
These bugs would have been serious, had there been a late crop
of pods.

Florida Agricultural Experiment Station


P. H. Rolfs, Director:
SI: I submit the following report of the assistant entomolo-
gist for the fiscal year ending June 30, 1919.
Assistant Entomologist.

The main work of the four months has been the study of the
leaf-footed plant-bug. A part of the time was devoted to the
study of the big-legged plant-bug.

The leaf-footed plant bug, Leptoglossus phyllopus Linn., is a
common and important insect pest of the southern states. It is
a member of the family Coreidae, and is distinguished from Lep-
toglossus oppositus by the markings. It is a dark brown bug
with a conspicuous cream-colored band across the apical part of
the wings. Leptoglossus opposites does not bear this band. Lep-
toglossus phyllopus is 2/3-inch in length, .18-inch in width at
the apex of the thorax, 1/25-inch in width at the base of the
thorax, and the length of the thorax is 1/12-inch. The head is
very small and cone-shaped, 1/16-inch in width and 1/12-inch in
length. The apical clear part of the wings is somewhat darker
than the basal. The legs and antennae are brown at the base
and light red-brown at the extremities. There are four antenna
segments. The tibia of the posterior leg is expanded into a flat
leaf-like structure with notched edge and bears a white spot. It
is from this structure that the bug gets its name. The dorsal
abdomen is bright orange-yellow under the wing covers. This
shows when the insect is in flight.
The damage done by Leptoglossus is not limited to garden
crops, but includes fruits and flowers. It occurs in large num-
bers on orange, sunflower, radish, thistle, tomato, rose bushes,
Irish potatoes, cowpeas, beans and elderberries, and has been
reported on cabbage, cucumber, cantaloupe, velvet beans, beg-
garweed, blackberries, eggplant, asparagus, strawberry, rattle
box and chinquapin. References to it on other plants include
wheat, rice, corn, apricots, peaches, plums, sorghum, pecans,
currants and cotton bolls. The damage is done by piercing the


Annual Report, 1919

host plant and sucking the juices from it. The mouth is in the
form of a long sucking tube with which it makes a puncture in
the leaf, stem or fruit. These punctures cause the leaf to become
spotted, each puncture making a brown withered spot.
In the early spring, about the first of March, the bugs are
found around thistle, clustering in groups on the stems. These
are the adults which have wintered over under the leaves of the
thistle plant. These adults feed for a short time and then begin
mating. They are in copula for several hours at a time and con-
tinue feeding. Three to four days after copulation begins eggs
are laid. About the middle of March eggs may be found along
the stems and ribs of the leaves of the host plant. The eggs are
iridescent green and are shaped like a barrel, flattened on the
side attached to the leaf. They are always in a row end to end
and there may be as many as 18 or 20 in the row, but usually
there are only 10 or 12. Each egg is 1/20-inch in length and .038-
inch in width. Toward one end is a circular marking, which is
the opening or cap. This has a series of minute spines around
it. The eggs are not known to be parasitized and almost all of
them are fertile and hatch.
The young bugs hatch nine days after the eggs are laid. They
are gregarious at first and cluster around the shells. They are,
of course. wingless and so are restricted to the plant on which
they are hatched and its immediate vicinity. This limits them
to a host plant longer lived than most truck crops. The first
instar nymph measures 1/10-inch, is entirely orange-red and
lasts about an hour, when the bug moults. The second instar
nymph is bright orange-red with dark brown legs and antennae
and dark brown tubercles on the abdomen. In this stage the bugs
resemble ants or tiny red spiders. They are 1/8-inch in length
and moult after two or three days. The third instar nymph
attains a size of 1/3-inch. It looks very much the same as in the
second instar, with still larger and darker appendages and tuber-
cles. This stage lasts from 7 to 14 days. The fourth instar
nymph begins to show more resemblance to the adult bug. The
tibial expansion begins to show and the body is darker. The
thorax shows the triangular shape and is dark brown with red
on its edge. After 24 to 28 days in this stage the bug again
moults and the nymph has reached the fifth nymphal stage. The
bug in this stage is dark brown above and grayish brown
beneath. The wing pads show very distinctly and the legs and
antennae are brown at the base and lighter reddish-brown at the


Florida Agricultural Experiment Station

extremities. The bug is 1/2-inch in length. The fifth nymphal
stage lasts from about 30 to 32 days. It takes altogether from
84 to 88 days to complete the life cycle.
Leptoglossus is parasitized by a Tachinid fly, Trichopoda pen-
nipes Fabr. This fly lays its eggs on the head and thorax of
Leptoglossus, sometimes on or under the wings and frequently
on the ventral surface of the body. The eggs are laid one at a
time, but one Leptoglossus may have as many as four or five
eggs. Leptoglossus tries to prevent the fly from getting on it
and is much disturbed by its presence. The fly alights suddenly
and flies again before the bug can get away or brush it off. After
the egg is laid the bug may try to rub it off, but it is glued on
firmly. Eggs are seldom found on immature bugs. The larval
Trichopoda hatches from 18 to 25 days after it is laid. It punc-
tures its way thru the integument of Leptoglossus, works down
into the body cavity, and there it develops, living on the juices of
Leptoglossus and eventually eating the vital organs. When
mature it forces its way out thru the end of the abdomen of the
host and drops to the ground where it soon pupates. The host
dies shortly before the emerging of the larva. Only one larva
develops in each parasitized Leptoglossus.
The pupal stage of Trichopoda is from 9 to 15 days. Soon
after emerging the adults mate and egg-laying begins. The
mature Trichopoda is about a half-inch in length. It is a black
fly with yellowish abdomen. The thorax is striped black and
yellow. In the male the tip of the abdomen is black and the
wings are wholly black. The female has a yellow abdomen and
yellow at the base and along the margin of the wings. Tricho-
poda is commonly seen in the regions where Leptoglossus occurs,
on the flowers of the plants on which Leptoglossus lives. Of
those caught in the very early spring, about two out of every
three Leptoglossus were parasitized. The eggs of Trichopoda
are very conspicuous, cream-colored, 1/45 of an inch in length
and 1/70 of an inch in width. Other dipterous insects are
thought to be parasitic on Leptoglossus, but were not raised in
this study. Red mites were frequently found on Leptoglossus.
Very few Leptoglossus are seen between the middle of April
and the middle of June. Those of the first group have died and
the young ones have not yet matured. During the second week
in June many adults were found on the ripening heads of the


Annual Report, 1919

It is not thought advisable to use sprays in the control of
these insects. Picking or shaking them off into nets is more
practicable. This should be done in the early morning when the
insects are sluggish. Cutting out thistle will destroy tneir
hibernating place.
Trap crops might also be suggested as a means of control. The
adult Leptoglossus is fond of sunflower and will be found on the
seeded heads in the early morning. Crotalaria might be used
as a trap crop, but has not been experimented with as yet. Rows
of eggs were found along the edge of fence posts adjoining the
garden. Such places should be watched and the eggs and young
destroyed before they can get to the host plant.


The big-legged plant bug, Acanthocephala femorata Fab., is a
member of the family Coreidae and is closely related to Lepto-
glossus phyllopus, to which it bears a great resemblance in struc-
ture, appearance, habits and life history. It is widely distributed
and has been found on a wide range of both wild and cultivated
Acanthocephala is a large brown bug 1 inch long and 2/5 inch
wide at the thorax. The antennae are lighter brown in color,
2/3 inch in length and consist of four segments. The integument
is very rough, especially the thorax, which is covered with coarse
warts or bumps. The femora are very large and rough in the
female and the tibiae of the male are large and flattened. There
is an oily exudate which has a very unpleasant odor suggesting
that of crushed cherries.
It appears first in appreciable numbers late in March, feeding
on the thistle. It is thought to hibernate in the woods nearby
and has been known to live thru several months of freezing
weather in North Carolina. Only adults are found as early as
March, and they soon mate and lay eggs. The eggs are laid on
the under side of the leaves of the thistle, radish or composite on
which they are feeding. The eggs are 1/10 inch long by 7/100
inch wide, very pretty, pearl-shaped and opalescent; in fact,
they look much like seed pearls. They are light greenish when
first laid, but get darker as they approach maturity and become
streaked with red. They are usually laid singly, but sometimes
groups of two or three or even more may be found on the same


Florida Agricultural Experiment Station

leaf. Sometimes they are found on fence posts and in the woods
on Spanish moss. The eggs hatch 12 days after they are laid.
The newly hatched nymph is pale yellow with bright red
spines, legs and antennae. The tibiae are yellow with black tarsi
and claws. The eyes are red. These little bugs look like red
spiders when first seen, because of the round form of the abdo-
men. They are 15/100 inch in length with four-jointed antennae
almost as long as the body and which they carry projected out in
front of them. The abdomen is usually carried at right angles
to the thorax and gives the bug a unique bob-tailed effect.
The first instar lasts from two to four days, when the bug
moults and becomes much darker in color. The body of the sec-
ond instar nymph is gray-brown, the femora are red, the tibiae
brown and the tarsi yellow. The antennae are red, darker than
the first instar. The length of the bug is about 1/5 inch. This
stage lasts from 10 to 12 days. The third instar is much like the
second, except that the femora have turned brown and the edges
of the abdomen somewhat more gray and more distinctly scal-
loped. Vestiges of wing-pads show. The length of this period
is not known, as it was not possible to carry the life history fur-
ther in the time taken for this investigation. There are prob-
ably five instars and not much change except in size and develop-
ment of the wing-pads. The entire life cycle must take as much
as 85 or 90 days for completion.
All during the nymphal period the bug is dependent on crawl-
ing from place to place, as there are no wings until it reaches
maturity. It is an active bug, but nevertheless cannot wander
far from the host plant on which it is hatched. This means that
it could not survive on a plant that did not continue succulent at
least as long as the nymphal period of the bug.
The adult bugs do the most injury, especially in places where
they cluster together and feed for any length of time. They are
often found in such clusters on the stem of a plant just below the
flower head. They injure the plant by piercing it with their long
sucking mouth parts and .pumping out the juices. Every place
thus punctured makes a brown withered spot. The stem, leaf,
seeding flower or the fruit may be attacked.
Acanthocephala is parasitized by two Tachinid flies and a Sar-
cophagid. The Tachinids are Trichopoda pennipes and Tricho-
poda lanipes. Trichopoda pennipes is a medium-sized black fly,
a third to half an inch in length. It has yellow on the abdomen;
in the male the abdomen is yellow-tipped with black. The wings


Annual Report, 1919

are black and the wings of the female have yellow at the base.
Trichopoda lanipes is similar to pennipes but is somewhat larger
and the abdomen is gray or black. The life cycle of the two flies
is much the same. The adults are seen flying around the plants
on which the Acanthocephala are feeding. The eggs are cream-
colored, 1/4 of an inch in length and 1/70 of an inch in width.
They are laid on the head or thorax of the host or on the under
surface of the body and sometimes even on the wings. As soon
as the larva hatches it eats its way into the body of the host and
there lives, eating the internal organs and eventually causing the
death of the host. The length of the egg and larval stage is from
18 to 24 days. Pupation takes place soon after leaving the host.
The larva is a typical dipterous larva, thick and creamy-white
in color. The pupa case is .26 inch long, 1/8 inch wide, dark
reddish brown and hard. It consists of seven segments. The
pupal stage lasts from 11 to 15 days, when the adult fly is
hatched. The adults mate within two or three days and egg-lay-
ing begins.
Sarcophaga .ternodontis Towns. is similar in appearance to
the common housefly, Musca domestic. It is gray with striped
gray and black thorax and mottled gray and black abdomen. Its
life history is similar to that of Trichopoda except that the pupal
stage is longer, about 25 days.
The number of Acanthocephala parasitized has not been defi-
nitely determined. Only one out of every six or seven of the
first adults seen showed signs of being parasitized; later the pro-
portion was somewhat larger. From the last of April to the last
of May almost no adults are seen. About the third week in May
young Acanthocephala are found in the woods and garden. The
adults which wintered over have probably all died and the first
season's brood have not matured. Extent of parasitism on later
broods was not observed.
To control Acanthocephala it is advisable to knock or pick the
bugs off into a pan containing kerosene. They are less active in
the early morning and can be found feeding at that time. Trap
crops such as sunflower or radish might be used to attract them
away from the more valuable garden plants.


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