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Group Title: Bulletin - University of Florida Agricultural Experiment Station ; no. 165
Title: A preliminary report upon an improved method of controlling the boll weevil
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Permanent Link: http://ufdc.ufl.edu/UF00027080/00001
 Material Information
Title: A preliminary report upon an improved method of controlling the boll weevil
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 72 p. : ill., charts ; 23 cm.
Language: English
Creator: Smith, George D ( George Durward ), b. 1886
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1922
 Subjects
Subject: Boll weevil -- Control -- Florida   ( lcsh )
Cotton -- Diseases and pests -- Control -- Florida   ( lcsh )
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: by Geo. D. Smith.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
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Bibliographic ID: UF00027080
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000922811
oclc - 18171340
notis - AEN3320

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    Introduction
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    Table of Contents
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Full Text


Bulletin 165


October, 1922


UNIVERSITY OF FLORIDA

Agricultural Experiment Station











A Preliminary Report Upon an Improved


Method of Controlling the


Boll Weevil




By

GEO. D. SMITH



IMPORTANT NOTE
The method of boll weevil control described in this publication has been
thoroughly tested in the field in Florida, and is recommended for use of cotton
growers of that state alone.
Farmers in other states should not attempt to make use of the control
method unless the date of completion of spring emergence of the weevil is
definitely known. This information should be secured from your own State
Entomologist or Experiment Station, whose advice should be sought before
attem ting the use of this method of boll weevil control.
WILMON NEWELL,
Director.

Bulletins will be sent free upon application to the Experiment Station,
GAINESVILLE, FLORIDA











BOARD OF CONTROL
P. K. YONGE, Chairman, Pensacola
E. L. WARTMANN, Citra
J. B. SUTTON, Tampa
W. L. WEAVER, Perry
J. C. COOPER, JR., Jacksonville
J. T. DIAMOND, Secretary, Tallahassee
J. G. KELLUM, Auditor, Tallahassee

STATION STAFF
WILMON NEWELL, D. Sc., Director
JOHN M. SCOTT, B. S., Vice Director and Animal Industrialist
J. R. WATSON, A. M., Entomologist
R. W. RUPRECHT, Ph. D., Chemist
0. F. BURGER, D. Sc., Plant Pathologist
MISS RUBY NEWHALL, Secretary
A. H. BEYER, M. S., Assistant Entomologist
J. M. COLEMAN, B. S., Assistant Chemist
C. E. BELL, B. S., Assistant Chemist
G. F. WEBER, Ph. D., Assistant Plant Pathologist
W. E. STOKES, Assistant Grass and Forage Crop Investigator
HAROLD MOWRY, Assistant Horticulturist
T. VAN HYNING, Librarian
RALPH STOUTAMIRE, B. S. A., Editor
MISS MARY E. Roux, Mailing Clerk
A. W. LELAND, Farm Foreman
K. H. GRAHAM, Auditor
MISS RETTA MCQUARRIE, Assistant to Auditor
J. H. JEFFRIES, Superintentendent Citrus Experiment Station
(Lake Alfred)
W. B. TISDALE, Ph. D., Assistant Plant Pathologist, Tobacco Ex-
periment Station (Quincy)
JESSE REEVES, Foreman, Tobacco Experiment Station (Quincy)










INTRODUCTION
By WILMON NEWELL
Prior to the advent of the boll weevil cotton was the most val-
uable and dependable crop available to the southern farmer. As
a crop it was seldom a total failure. As a source of credit it was
unsurpassed. A cash market existed for it at all times. With
the coming of the weevil cotton growing became, in many sec-
tions, a hazardous occupation, a game of chance with most of
the chances against the grower. Profits from cotton culture be-
came so uncertain that the farmer who engaged in it exclusively
found himself, as a rule, with neither cash nor credit.
Numerous efforts were made to find other dependable sources
of revenue for the cotton grower. In some instances these efforts
were successful and there are southern communities that are
today even more prosperous than they were in the days when
"Cotton was King." The boll weevil has undoubtedly taught the
southern farmer the valuable lesson of diversification, but the
price paid for it has been, to say the least, exorbitant (the an-
nual reduction in cotton yield ascribed to the boll weevil is now
variously estimated at from four to six million bales).
Nevertheless, no crop has been found for the South which
possesses the many advantages characteristic of cotton. The
fact that in former days the culture of cotton was abused, thru
its being grown to the practical exclusion of other crops, does
not in the least affect its value as a staple crop.
In North Florida the consequences following the boll weevil
invasion were particularly unfortunate. For a time after it
was realized that the boll weevil would make cotton growing
generally unprofitable, the farmers turned their attention to
raising cattle and hogs. During the war and post-war periods,
with prices high, the returns were very satisfactory but soon
the prices for cattle and hogs fell to the level of, or below, the
cost of production. Growing peanuts was a similar experience:
at first prices were high, then fell to the point where the farmer
could not secure as much for his crop as it had cost him to
produce it.
It is frankly admitted that during the last two years the
farmer of North Florida has needed a dependable cash crop as
never before. This situation has been keenly realized by the
officials of the State Plant Board and the University of Florida






Florida Agricultural Experiment Station


Agricultural Experiment Station. They, too, have tried to find
some crop, adapted to this region, which would take the place
of cotton.
Confronted by this situation, the State Plant Board inaugu-
rated an intensive investigation of the boll weevil, believing that
the "last word" in control measures had not been reached.
For carrying out its investigations the Board employed, as
associate entomologist, George D. Smith, formerly with the
Bureau of Entomology, United States Department of Agricul-
ture. His experiments, conducted in three Florida counties dur-
ing 1922, have given most gratifying results; so gratifying and
encouraging, in fact, that it is felt that a new era is at hand
for the Florida cotton grower.
For the last 25 years both planters and entomologists have
striven to find some sure and certain way of outwitting or con-
trolling the boll weevil. These efforts have not been entirely un-
productive; much has been learned regarding the weevil, its
habits, hibernation, migrations and seasonal activities.
This information has pointed the way to a number of measures
which are more or less contributory to a partial control of the
pest but all of them together are not sufficient to insure a
profitable crop in a year of normal weevil abundance. The
measures referred to include such steps as destroying the cotton
plants early in the fall, using early maturing varieties, planting
early, cultivating the crop frequently, gathering infested squares
and, in recent years, using the calcium arsenate method of poison-
ing recommended by the Bureau of Entomology, United States
Department of Agriculture.
With the accumulated data of many years at his command
and with 13 years' experience in studying the weevil problem,
Mr. Smith began his investigations with the State Plant Board.
To him must be given the credit of discovering what had been
overlooked by all previous investigators, namely, the weak point
in the weevil's existence and of perceiving how it could be taken
advantage of in making a successful attack upon the insect.
The method of control which he has evolved, while in a way a
logical outgrowth of past investigations, nevertheless, is the big-
gest step toward complete repression of the pest that has ever
been made. This happy development is a most striking justi-
fication for long continued and persistent scientific investigation
of difficult problems.
Altho much has been accomplished, much remains to be done






Bulletin 165, Improved Method Boll Weevil Control 5

in the way of research and experimentation and it is the pur-
pose of the State Plant Board and the Experiment Station to
continue their joint efforts to still further improve the methods of
boll weevil control.
Those who have followed closely and critically the experi-
mental work during 1922 and have visited and examined the
treated cotton fields from time to time, have come inevitably to
the conviction that the relatively simple control method which
has been evolved thru Mr. Smith's work now makes it possible
for the Florida grower of upland cotton to insure for himself
at least 90 percent of a normal crop, so far as weevil damage
is concerned.
It has been evident, on poor soils and good, in fields with fer-
tilizer and those without, that the treated fields produced prac-
tically as much cotton as if there had been no boll weevils; while
untreated fields and check areas-usually only a few hundred
feet from the treated fields-produced insufficient cotton to pay
for seed and cultivation. How this result has been obtained is
explained by Mr. Smith in the pages following.
So striking and uniform are the results secured in the 1922
experiments that we would feel remiss in our obligations to the
farmers of Florida if we deferred placing this information before
them until after the experiments have been repeated another
year.
Here, undoubtedly, is information by which any intelligent
farmer can materially increase his cotton crop, and the cost of
applying it is so low that the method can be profitably used
upon the poorest of cotton lands in the state.
The experimental results, therefore, are given to the public
in order that they may be made use of during the coming year.
No claim is made that a perfect weevil remedy has been de-
veloped, but only that a very great advance has been made in
the methods of controlling the pest and reducing its damage.
The reader will note in the pages following, that Mr. Smith's
experiments have been made on typical cotton lands of North
Florida, lands consisting largely of Norfolk and Orangeburg
sandy loam, rolling and well-drained. On such lands the cot-
ton plant normally shows a very determinate habit of growth
and matures its crop relatively early, whether weevils are pres-
ent or not, a condition somewhat at variance with that which
prevails on the alluvial lands of Texas, Louisiana and Mississippi.
At the same time, conditions in North Florida are perhaps as






6 Florida Agricultural Experiment Station

favorable to a large winter survival of weevils as anywhere in
the South.
While, for the present, the improved method is actually recom-
mended for Florida only, there appears to be no reason, on theo-
retical grounds at least, why the method cannot be successfully
adapted to conditions existing elsewhere in the cotton belt.
While there have been under way investigations to ascertain
the value of the improved method of control when applied in
connection with sea island cotton, they have not reached the
point yet where it is felt that recommendations can be safely
made.







Bulletin 165, Improved Method Boll Weevil Control


CONTENTS
PAGE
PAST EFFORTS TO CONTROL THE BOLL WEEVIL.......................... ....... 9
Efforts at Control ~vith Poisons ...............................- ....- 10
EXPERIMENTS ALONG A NEW LINE...... -............ ... -....... ---- ...- 14
THE IMPROVED METHOD OF CONTROL.. .... .............. ...... ....... 15
Relation of Hibernation to Weevil Control..... ........... ........ 16
Relation of the Date of Planting to Control................ ........ 17
Relation of the Late Planting to Control ............ .... ........ 18
Relation of Square Stripping to Yield......................................... 18
A accelerated Fruiting ............................................... ... 18
Setting a Bottom, Middle and Top Crop in 30 Days.......... .... 24
Relation of Square Removal to Maturity of Crop ....... .... 24
Relation of Weevil's Life History to Control................. 24
H ibernation ...... ... ..... ....... ..... 27
THE EXPERIMENTS OF 1922.............. ........... 28
Manner of Making Field Tests ................... .... 28
Manner of Applying Poison.................. 30
Infestation Records ....................... ........ ....... 30
How "Profit" or "Loss" is Determined ..... .. 31
Plot Experim ents ............ ... ..... .. .... 32
Experiments on Sanders Plantation.... .. ..... 32
Field N o. 1............................. .. ........ ..... ... 32
Field No. 2............................. ......... .. .. 33
Field No. 3....................................... ... 34
Field No. 4 ............. ............................... .. 34
Field No. 5-... .......... ...-.... .... ..... 35
Infestation Records ..................... .......... .... 36
Summary of Results ................................. .. 37
Experiment by A. Hodge................... ........ 37
A Test in Suwannee County......... ............. 39
A Test in Alachua County ............. 40
A Plantation Test............... ................... ......... 43
Check Fields .......................... ........ .... .. ... 45
Treated Fields ................................... 47
F ield N o. 1............................ ........... 47
F ield N o. 2....... ......... .. .......... 47
F ield N o. 3.............. ..... .............. ..... 48
Field N o. 4............. ............. ..... ... 49
Field N o. 5... ........................ .. .... 49
Field N o. 6..................................... ... -.... .... .. .. 50
F field N o. 7- --........ .. ................................ 51
Field No. 8...... ...... ..............- .. ........ 53
Field No. 9-................................ ........ 54
Infestation Records --.......--- ..............- .......... 55
Cost of Boll Weevil Control................. ............... 56
Production and Profits.. ..-....----- ...... ........... ......... 57







8 Florida Agricultural Experiment Station

Results of Applying Control Measures Too Early................. .......... 57
Check Field ................................. 58
Treated Fields ..-..---- -----.....-.....--- -- .. -- .. 58
Field No. 1 ................................ .-- 58
Field No. 2 ......... -------...- --------.... 59
Field N o. 3.................................... ...- 60
Summary, All Field Experiments, Upland Cotton ....... ............ 61
Poisoning Experiments in Cages ........ .............. ....... 62
How TO USE THE IMPROVED METHOD OF CONTROL................. ............. 65
Principles Involved ............. ............... .... .. ........... 65
Removal of Squares.. .. ----......... .... ....--......-. .. .....-- .. 65
Poisons to U se....... .... .-- ---..-.. ...- .-- .. ..-- - 67
Dusting Machinery ...... ..... ...-...- .. .....-- 68
Caring for the Poison -....-....... .. ....-- -- .... 70
Applying the Poison- ...-..- ....-...--- -.. .. 70
Effect of Rains on Poison ............ .. ...-..... ....- .-- 71
Amount of Poison to Purchase.. ................... .. ........ 72
Profits Proportionate to Care of Crop ... ........... .. ............. 72














PRELIMINARY REPORT UPON AN IMPROVED METHOD
OF CONTROLLING THE BOLL WEEVIL'
By GEO. D. SMITH
Associate Entomologist,
State Plant Board of Florida
As there is available, thru state and federal publications, a
large amount of information concerning the boll weevil, its in-
vasion of the cotton-growing states, .ts habits, life history, etc.,
no attempt is made in the present paper to discuss these matters
except in so far as they have more or less bearing upon the
experimental work and results herein described.

PAST EFFORTS TO CONTROL THE BOLL WEEVIL

Efforts to control the boll weevil very naturally commenced
with its appearance in alarming numbers in the southern part of
Texas in 1894 and have continued ever since. In fact, the his-
tory of the boll weevil in the South has been one of unending
effort on the part of both cotton growers and scientists to find
some way of either satisfactorily outwitting the insect or re-
ducing its numbers to the point where profitable crops of cotton
would be assured.
These investigations have developed certain farm practices
which are of value in that they assist in bringing about a partial
control of the pest but, by themselves, are not effective enough
to insure good crops of cotton under normal weevil conditions.
The most important recommendations which have been made in
this regard are substantially as follows: Early fall destruction
of the cotton plants by burning, plowing under or grazing; de-
struction of volunteer cotton; destruction of hibernating weevils
by burning off stubble fields, ditch banks, margins of wooded
areas, etc.; selecting fields for cotton with a view to getting as
far as possible from the weevil's hibernating quarters; thoro
preparation of the seedbed; early planting, use of early-maturing
'Published also in the Quarterly Bulletin of the State Plant Board of
Florida, Vol VII, No. 1, October, 1922.






Florida Agricultural Experiment Station


varieties, use of fertilizers and thoro cultivation of the growing
crop.
EFFORTS AT CONTROL WITH POISONS

The idea of using a poison against the weevils has naturally
proven a very attractive one, to both planters and investigators.
As poison has been utilized in our experiments during 1922 and
as its intelligent use forms a necessary part of the improved
method of control which is described on subsequent pages, a
brief review of the efforts made to utilize poisons against the
boll weevil during the last 25 years may not ,e out of place at
this point.
Among the first things tried as remedies for the boll weevil,
upon the appearance of this pest in southern Texas, were arseni-
cal poisons. The first careful investigation of the weevil and its
habits was made in 1894, in southern Texas, by C. H. Tyler
Townsend, an entomologist of the Division of Entomology, United
States Department of Agriculture. After a study of the weevil
for two months, Professor Townsend recognized the possibility
of killing some of the weevils with arsenical poisons and in a
report upon his investigations, he says:
"Paris green or London purple, applied in solution of one pound
of poison to 150 gallons of water when the bolls begin to form,
may kill a certain per cent of the weevils, if good judgment is
used in its application."
That the use of poison against this insect was considered
possible, even promising, at the beginning of the investiga-
tions is shown by the following statement by L. O. Howard in
Circular 6, second series, Division of Entomology, issued April
2, 1895:
"Living as the larva does, in the interior of the bud or boll, it
cannot be reached by ordinary insecticides, although an applica-
tion of Paris green or London purple, as for the c )tton worm,
made when the bolls begin to form, may kill a certai- percentage
of the adult weevils, since these feed, to some extent, upon the
outside of the bolls."
The Division of Entomology made a thoro test of the arsenical
insecticides then in common use, such as paris green and london
purple, and established the fact that some of the over-wintered
weevils could be killed by paris green while the plants were still
small. Dr. Howard, writing in February, 1897', said, in reference
to the volunteer cotton which grows in southern Texas:
Insect Life, Vol. VII, p. 305, March, 1895.
'Circ. 18, sec. ser., Div. of Entomology, p. 6.







Bulletin 165, Improved Method Boll Weevil Control 11

"It should be understood at the outset that experience has shown
that none of the general applications of insecticides are of the
slightest value against this species as a means of protecting in-
fested fields. The weevil in its work in growing cotton is thor-
oughly protected against poisons, breeding as it does within the
blossoms and squares. As demonstrated by the experience of the
spring of 1896, poisons may be used as a means of destroying
over-wintered beetles on volunteer cotton. The beetles which have
survived the winter collect in the early spring on the first sprouts
which appear on old cotton and eat the partially expanded leaves
and the tender leaf stems, and at this stage can be poisoned by
the application of an arsenical to this new growth."
Dr. Howard did not recommend the use of the arsenical spray
upon the main field crop, but only on the volunteer and sprout
cotton for the destruction of the weevils which had lived thru
the winter.
After continued experiments in trying to poison the boll
weevil, the Division of Entomology recommended to the planters
in July, 1898', that use be made of a liquid spray of white
arsenic, molasses and water on the young plants of the main field
crop as well as on the volunteer cotton. This recommendation
was apparently not tested in actual field experiments in which
the yields from poisoned and non-poisoned cotton were deter-
mined, but was based upon the results of experiments made by
confining weevils in cages containing plants which had been
treated with the poisonous mixture. At the same time Dr. How-
ard laid special stress upon the importance of the cultural meth-
ods to reduce weevil ravages, the use of poison being suggested
as an auxiliary.
In 1899 F. W. Mally, state entomologist of Texas, undertook
extensive investigations of the boll weevil, which continued until
1902. Mally decided that the cultural methods were of first im-
portance in producing cotton in the weevil districts and at the
same time he concluded from his experiments that much good
could be accomplished by spraying the cotton early in the sea-
son with a mixture of white arsenic, arsenate of lead, molasses
and water. At the same time, actual experiments with the mix-
ture, made after cotton plants were fruiting, resulted in a re-
duction of from 5 to 25 percent in the number of weevils5. The
spraying of cotton with the mixtures recommended by Mally
became quite general in Texas during 1902 and 1903. Many ex-
pensive, complicated sprayers were purchased for the purpose
"Howard, L. 0., Circ. 33, sec. ser., Div. of Entomology.
"Report on the Boll Weevil," by F. W. Mally, Austin, Texas, August,
1902, p. 60.







Florida Agricultural Experiment Station


and much money was expended for the necessary poisons and
molasses. Many planters reported profitable results from such
spraying but gradually it was discontinued.
In 1904 B. W. Marston of Louisiana, who in that year visited
various parts of Texas, made experiments with paris green and
advocated its use as a boll weevil remedy. However, the use
of paris green was soon abandoned. The Bureau of Entomology,
having conducted further tests during 1904, came to the con-
clusion that profitable use of arsenical poisons against the weevil
could not be hoped for. Statements to that effect appear in sev-
eral of the Bureau's publications".
Wilmon Newell, of the Louisiana State Crop Pest Commis-
sion, began studying the use of poisons in controlling the boll
weevil in 1903 and, as the experiments both in cages and field
tests indicated that paris green could not be used successfully,
he turned his attention to the development of a new poison.
The paris green experiments were largely responsible for his
idea of testing other chemicals, as the experimental data had
shown that weevils could be killed with poison. The fact that
the soluble arsenic in paris green injured the cotton plants and
reduced the yield, even when used in very small quantities, led
Mr. Newell to make an effort to eliminate the soluble arsenic by
soaking the paris green in water before using.
The results in excluding the water-soluble arsenic were en-
couraging and it was then thought that a powdered form of
arsenate of lead, something unknown at that time, might solve
the difficulty. The finely powdered form of lead arsenate was
successfully made for the first time in Mr. Newell's laboratory
during 1904. The results of preliminary tests with this new
form of arsenate were published in July, 1908, in Circular 23
of the Louisiana State Crop Pest Commission.
In 1909 the writer conducted extensive field tests for control-
ling the weevil with powdered arsenate of lead under the direc-
tion of Mr. Newell. The results of these field tests were en-
couraging and were published as Bulletin 33 of the State Crop
Pest Commission of Louisiana in December, 1909. They indi-
cated very positively that a certain degree of control could be
secured by poisoning the weevil in early summer with lead
arsenate but that applications made in midsummer, during the
season of heavy rains, would not hold the weevil in check. The
OBulletin 45, Bureau of Entomology, pp. 42, 43, 112 and 113; Farmers'
Bulletin 211, pp. 21-22; Farmers' Bulletin 216, p. 24, etc.







Bulletin 165, Improved Method Boll Weevil Control 13

experiments showed a very definite profit and indicated the pos-
sibility of making still further progress in the use of poisons
against the weevil.
Certain very well-defined principles were established as being
necessary in the use of poisons for this insect. In the first place,
it was shown that, prior to the appearance of the first squares
the weevils could be poisoned in large numbers and that one or
two applications made just after the first squares appeared were
more profitable than later applications.
It was also demonstrated that when squares are on the cot-
ton plants it is difficult to force the poison down inside the in-
volucres, or shucks, surrounding the squares, where the weevil
commonly feeds, and many weevils are not poisoned. Various
types of dust guns were devised for forcing the poison into the
squares and buds, but it was soon found that the air blast
machine was the only one that was even partially successful.
In 1910 the writer was placed in charge of the boll weevil
poisoning tests for the Bureau of Entomology, United States
Department of Agriculture, at Tallulah, Louisiana. Tests were
made with powdered arsenate of lead on a very large scale from
1910 to 1914. The results corresponded quite closely to those
secured under Mr. Newell's direction in 1908-09 and the conclu-
sion was reached that, altho powdered arsenate of lead, used
during midsummer, would kill a great many weevils and give a
certain amount of control, it was impractical for the average
cotton grower to attempt its use.
B. R. Coad, who succeeded the writer in 1915, was placed in
charge of the experimental work at the Tallulah laboratory. He
turned his attention to the development of an improved form of
powdered calcium arsenate, and the results are now well known.
The so-called calcium arsenate method of weevil control has
not been found adapted to Florida conditions, for the principal
reason that several applications and relatively large amounts of
poison to the acre are required and the expense absorbs prac-
tically the difference between the cost of growing the crop and
its market value.
In fact, the United States Department of Agriculture does not
recommend this method for controlling the weevil on land which
is incapable of producing at least half a bale of cotton to the
acre in the absence of the boll weevil7. The Census of 1910
'Bulletin 875, U. S. D. A., p. 28.







Florida Agricultural Experiment Station


showed the normal production of cotton in Florida to be a quar-
ter of a bale to the acre.
It is, therefore, self-evident that the Florida farmer must have
a method of boll weevil control which can be utilized without
the necessity of purchasing expensive machinery and applying
large quantities of poison, involving the expenditure of several
dollars to the acre. We believe the method which has been
tested during the season of 1922, and which is described herein,
overcomes these difficulties, so far as short staple cotton is
concerned.
EXPERIMENTS ALONG A NEW LINE
It has long been known that the boll weevil can be quite ef-
fectively poisoned during the period preceding the appearance
of the first squares. However, the last of the over-wintering
weevils do not emerge from their hibernating quarters until sev-
eral days after the cotton plants normally begin square forma-
tion. A suitable application of lead or calcium arsenate, made
just before the squares appear, kills practically all weevils in
the field. But the weevils emerging later on deposit their eggs
in the early squares, thus starting the season's infestation. After
squares develop, the adult weevil is difficult to poison and the
poison, of course, has no effect on the eggs and larvae, which
are within the squares.
After several years of investigation it occurred to us that the
first weevil generation of the season might be largely disposed
of by removing or "stripping" from the cotton plants the first
squares of the season, and with them the eggs deposited by the
over-wintered weevils.
During 1919-21, while stationed at Madison, Florida, and en-
gaged in investigations for the Bureau of Entomology, United
States Department of Agriculture, the writer made experiments
in stripping squares from the cotton plants early in the season
and, while this disposed of the first infested squares, it was ob-
served that there always remained a considerable number of
weevils.
These experiments were encouraging in that the extra amount
of cotton produced on the stripped plots indicated that one
stripping, altho it did not clear the field of weevils, was slightly
beneficial and that two stripping, about ten days apart, would
insure a marked increase in the quantity of cotton produced. On
the other hand, two strippings might delay the fruiting of the







Bulletin 165, Improved Method Boll Weevil Control 15

plants to a dangerous degree. However, the condition in which
the cotton plant is left after removal of the squares is the very
condition under which poison can be applied with most telling
effect. Deprived of squares in which to hide and on which to
feed, the weevil must necessarily turn to the terminal or grow-
ing bud of the plant for food. It is very easy to literally fill this
terminal bud with a suitable poison by means of a good dust
gun.
At this time, also, the over-wintered weevils have only a few
more days to live and their instinct to survive urges them to
feed liberally. The application of poison to the terminal buds
at this stage has been followed, in all our experiments, by the
destruction of practically every weevil that escaped capture in
the stripping operation.
If the stripping is done about June 5 to 8, the number of
weevils still remaining in winter quarters and which can still
come to the cotton fields is of practically no consequence. These
few stragglers cannot increase sufficiently to seriously affect
the number of bolls set on the plants in the two months fol-
lowing.
Because such treatment of a cotton field may appear to the
reader somewhat radical and because an understanding of the
principles involved is quite necessary to a clear interpretation
of the experiments described on subsequent pages, we are giv-
ing, first, a description of the methods used and the factors in-
volved and, second, a detailed account of the experiments in
which these principles have been applied.
THE IMPROVED METHOD OF CONTROL
The method of control which the writer has evolved is simple.
In substance, it consists in clearing the cotton field, early in
June, of all the adult weevils and, at the same time, of destroying
their eggs and larvae; thus leaving the cotton plants free to
develop squares and bolls without weevil interference for the
succeeding seven or eight weeks.
Having disposed of the over-wintered weevils and their pro-
geny, no additional weevils of any consequence will come to the
field before the annual migration, which usually takes place
about August 1. Upland (short staple) cotton bolls, which are
more than half grown when the summer migration occurs, suc-
ceed in maturing and opening, because the first migratory weevils
arriving in the fields late in July turn to the squares and do not
attack the green bolls to any great extent.








Florida Agricultural Experiment Station


In this respect the treated field, on arrival of the first migra-
tory weevils, is in a condition comparable to that of any ordinary
cotton field earlier in the season. That is; while the weevils are
destroying the squares the bolls largely escape their attack.
In considering these facts it should be remembered that be-
fore the boll weevil appeared in Florida the cotton crop was nor-
mally "made" by the middle of August. On the Florida sandy
soils the cotton plant shows a very determinate habit of growth;
that is, it reaches practical maturity in the latter part of
summer and does not normally make an appreciable amount of
cotton after that time. Cleaning the cotton fields of weevils
early in June, therefore, affords the cotton plant almost as long
a period in which to set fruit as it enjoyed in a normal season
prior to the advent of the weevil.
This fact undoubtedly explains why, in the majority of our
experiments, yields have been secured practically as great as
those upon the same farms before the boll weevil came.
RELATION OF HIBERNATION TO WEEVIL CONTROL
Data obtained in the hibernation experiments, which have
been conducted for a number of years by both federal and state
investigators in various parts of the South, give us a very ac-
curate knowledge of the rate at which the weevils emerge from
hibernation. These experiments, involving observations on many
hundreds of thousands of weevils, show that fully 99 percent
of them are out of their winter quarters and in the cotton fields
by June 5. This is shown by reference to Table 1, taken from
Bulletin 926, United States Department of Agriculture.
TABLE 1.-PERCENTAGE OF TOTAL EMERGENCE OF BOLL WEEVILS AT DIF-
FERENT DATES AND AT DIFFERENT PLACES

Keathie Tallulah, Mansura, Dallas, Calvert, I Victoria, Madison,
Date La., 9 La. La Tex Tex., Tex. Fla.,
La., 1906 1907 1907 1919
1910 1 1911 1910 1 1909 1907 | 1908 I
Feb. 21 ................. 0.00 0.81 36.95 1.64 7.2 0.00 0.00 0.00 0.00 3.6
Feb. 28..-............... .00 .31 36.95 3.28 10.61 .00 .00 .00 12.01 5.03
Mar. 7................ .00 6.62 89.92 10.56 19.22 24.48 7.27 22.80 27.92 21.9
Mar. 14.................. .00 10.09 63.83 15.69 19.73 36.36 23.63 31.90 48.23 30.2
Mar. 21 ................. .00 13.56 70.35 21.19 23.24 57.14 45.45 44.30 66.24 34.2
Mar. 28.................. 3.93 23.34 72.52 38.05 30.96 71.72 55.45 57.20 79.35 36.4
Apr. 4.................. 6.87 35.951 74.69 46.53 38.16 75.70 63.63 64.20 84.16 41.4
Apr. 11................. 24.54 41.95 81.21 49.42 43.87 81.28 68.18 70.40 89.58 52.3
Apr. 18............... 32.11 46.05 87.73 52.41 47.78 84.46 74.54 77.40 93.80 57.7
Apr. 25 ............. 40.67 48.89 96.42 53.86 56.39 85.74 87.27 79.51 95.02 58.4
May 2................ .7 61.83 96.42 60.41 61.30 88.62 90.91 82.62 95.88 61.2
May 9............... 60.44 70.66 98.59 72.35 67.51 92.30 91.82 88.73 97.50 85.4
May 16............ 72.22 75.39 98.59 75.64 75.12 95.75 94.55 91.94 98.36 90.4
May 23.............. 86.41 88.64 98.59 84.77 82.43 98.76 98.18 94.95 98.92 92.5
May 30............. 91.60 93.69 98.59 92.77 89.73 99.34 98.18 97.56 99.18 94.7
June 6.............. 97.36 99.05 100.00 98.43 96.83 99.78 99.09 99.17 99.90 98.5
June 13............. 99.19 99.68 100.00 99.89 97.8 99.88 99.09 99.68 99.97 99.1
June 20................. 99.61 99.68 100.001100.00 98.74 100.00 100.00 99.99 100.00 99.6
June 27.............. 99.89 100.00 100.00.100|00 99.94 100.0 100.0 100.00 100.00 99.9
July 4.................. 00 1000 00.0010000 100.00 00.00 100.00 100.00 100.00 99.9
July 7 ................ ...._ -- -.. --....... I ... .... -- ... ........ .. .................. .. ...... 100.00






Bulletin 165, Improved Method Boll Weevil Control 17

The data presented in Table 1 indicate quite clearly that
June 5 is about the earliest date at which the control measures
can be successfully applied. That is, on June 5 it is possible, by
taking off all squares, to destroy all weevil eggs and larvae. At
the same time, as nearly all weevils are feeding inside of the
involucres (shucks) of the squares, it is possible to destroy a
large percent of the adult weevils with the same operation.
When all squares have been removed, the weevils that were
not captured by the stripping operation are forced to feed in the
tender buds of the cotton plants, in the same manner as before
the squares developed, and then a single dust application of any
suitable arsenical will destroy practically all of them.

RELATION OF DATE OF PLANTING TO CONTROL
The date of planting is very important where the improved
method of control is to be used. In Florida the weather is usually
warm enough to permit planting about March 10, and some
farmers plant their cotton at this extremely early date. It has
been found during the course of these investigations that non-
fertilized cotton planted about the last week in March will,
under normal conditions, be in the right fruiting stage for treat-
ment about June 5. If much fertilizer is used it is better to
plant a week later. Should the season be late, the treatment
can be delayed a few days or until enough squares have ap-
peared on the plants to act as traps for the adult weevils.
On the other hand, planting too early, especially if the season
is an early one and the cotton grows rapidly, involves a great
deal more labor in picking off the squares at the time of treat-
ment. It must be remembered that the rate at which the weevils
emerge from hibernation is not accelerated by an early season
to the same degree that the growth of the cotton plant is and,
regardless of whether the season is early or late, the treatment
for the weevil should not be given earlier than about June 5.
Extremely early planting also means early hatching of the first
generation of weevils. That is, extremely early cotton often
produces enough squares to supply a generation of adults during
the last week in May, before all over-wintered weevils are out
of hibernation.
Therefore, it is advisable to plant the cotton only moderately
early, say the last week of March, and thus have the plants
ready to treat at the proper time.






Florida Agricultural Experiment Station


RELATION OF LATE PLANTING TO CONTROL
Some of our readers might suggest that it would be better
to wait until late in April before planting, so that there would
be no necessity for removing the squares, with the idea that
applications of poison alone would dispose of all the adult weevils.
According to the writer's observations, the late planting of
cotton is dangerous, as the plants are so small and their root
systems so poorly developed in June that it is almost impossible
for them to produce a good crop of matured bolls before the
annual migration of the weevil from untreated fields. It is better
to plant the crop too early than too late. The larger the cotton
plant at the time of taking off the squares the greater the amount
of fruit it can put on within a few days afterward.

RELATION OF SQUARE STRIPPING TO YIELD
At first thought it may appear that a considerable amount of
cotton would be destroyed or lost by removal of the first few
squares, say, an average of about two large squares to the
plant thruout the field. It has been demonstrated that the cotton
plant normally sheds about 60 percent of its fruit during the
growing season. Therefore, a loss of two squares to the plant,
on the average, should not affect the yield.
It is true that heretofore the planter has attached great im-
portance to these first squares, considering them the substance
of his early bottom crop, and has pinned his crop prospects to
the production of as many early bolls as possible, knowing that
the weevil would not permit the maturing of later ones.
However, removal of the early squares in our experiments
was followed by a remarkable reaction on the part of the plant
itself. In all cases, removal of the squares was followed by a
rapid increase in the height of the plants and this was closely
followed by a profuse development of new squares. So pro-
nounced has been this acceleration, or stimulation, of fruiting
that it seems highly probable that, even with no weevils pres-
ent, removal of all squares early in June would actually result
in increasing the yield of cotton!
ACCELERATED FRUITING
The effect of square stripping, just described, may be likened
in a sense to the stimulation of growth which follows the pruning
of a perennial plant or shrub, such as the peach or apple, and
it is to be remembered in this connection that in tropical coun-






Bulletin 165, Improved Method Boll Weevil Control 19

tries the cotton .plant is a perennial and attains the size of a
very large shrub. Cotton is an annual in the United States only
because it is killed by frost.
We do not know of any other instance of plant behavior with
which this phenomenon of accelerated fruiting can be compared.
A somewhat comparable reaction to pruning is evident, how-
ever, in the case of okra, which belongs to the same family. The
growing and fruiting habits of cotton and okra are similar in
many respects. It is well known to gardeners generally that if
the first-appearing pods of okra are allowed to mature their
seed, the fruiting is greatly retarded In other words, to secure
a bountiful supply of green pods, it is essential that all pods be
frequently pruned from the plants.
A somewhat analogous condition exists in the case of the
cotton plant. If the first few squares that come on the plant
are allowed to set bolls and mature them, it is well into July
before there is much indication of a middle crop being set and
August before the top crop appears. It seems that while the
plant is devoting its energies to forming the lint and seed in the
lower bolls there is little tendency to produce additional squares
and blossoms. Fertilizer may be so used as to greatly stimulate
the rate of setting of the three so-called crops and, within cer-
tain limits, can be used to hasten it.
In order to determine with a fair degree of accuracy the ex-
tent of stimulation of fruiting which follows removal of the
squares, an experiment was made in which six varieties of up-
land cotton were utilized. The cotton was planted March 20 in
well-prepared seedbeds. Kainit and nitrate of soda were applied
at the rate of 100 pounds of each to the acre. The land was
well-drained and typical of the Norfolk sandy soils of Madison
County. All six varieties were given the same cultivation and
treated alike in eveiy respect thruout the season.
On June 7 the first blossoms were just making their appear-
ance and it was decided to remove all squares from one row of
each variety and leave the adjacent row as a check. Beginning
on June 8 and continuing until July 16, the number of blossoms
produced by the stripped and non-stripped rows each day was
recorded. By the latter date the boll weevils had increased in
the field to such an extent as to interfere with the development
of blossoms and the observations were discontinued. The rate
of blossoming of both the stripped and non-stripped plants, in
the case of the six varieties, is shown in Table 2.







TABLE 2.-RECORD OF DAILY BLOSSOMING BY Six VARIETIES OF COTTON, MADISON, FLORIDA, 1922

NUMBER OF BLOSSOMS m

Date of King Lewis 63 Meade Council Toole DeSoto Lightning Express
Examina-
tion 66 Plats 62 Plants 828 ts Pant Plant 89 Plants 90Plants 86 Plan 4 Plat83Plants 31 Plants 44 Plants
Plants Non- 82 Plants Non- 91 Plants Non- 90 Plants Non- trplant Non- Non-
Stried stStripped* stied Strippedst Stripped Stripped d Stripped st ed Stripped* stripped
strippe stripped stripped stripped 'tripped
June 8......... 10 6 0 4 0 11 0 | 8 0 4
June 9............. 4 0 14 0 7 0 11 0 9 0 12
June 10....... 0 6 0 12 0 6 0 10 0 10 0 9
June 11 ............ 0 7 0 10 0 11 0 12 0 11 0 10 '
June 12 ............. 0 9 0 7 0 15 0 15 0 8 0 11 1
June 13 0 11 0 12 0 15 0 1 13 3 0 11
lune 14 ...... 0 12 0 11 0 11 0 21 0 10 0 19 8
June 15.. .... 0 13 0 14 0 16 0 14 0 10 0 21
June 16 ........ 15 0 17 0 21 0 12 0 11 0 26
June 17........ 0 13 0 16 0 20 0 15 0 12 0 20
June 18....... 0 12 0 19 0 21 0 17 0 15 0 18
June 19 ...... 0 14 0 21 0 16 0 14 0 14 0 16
June20 .... 0 15 0 27 2 15 2 9 2 12 1 14
June 21 ..... 1 4 0 9 0 13 0 6 0 11 1 11
June 22.... 1 10 1 13 6 16 2 9 1 9 6 14
June 23.......... 9 16 5 13 6 22 2 11 6 8 2 20
June 24 ... 19 38 19 42 33 58 37 10 11 29 2 49
June25 21 25 20 32 33 35 39 26 22 25 3 22
June 26 ......... 23 23 19 29 35 30 42 31 26 29 4 14
June 27.. 16 16 20 18 25 27 24 21 22 21 10 21
June 28 33 22 34 31 41 33 44 39 40 30 24 17
June 29.. 50 50 75 75 75 60 58 38 49 38 40 20
June 30 ..... 94 98 80 80 76 56 56 44 98 85 56 49
July 1 ..... 96 93 74 72 72 61 92 76 112 111 29 27
July 2 ....... 67 42 79 71 88 79 73 73 90 67 30 23
July 3..... 8 61 121 81 95 70 122 116 116 75 27 42 ct
July 4 ...... 60 35 80 86 85 78 96 73 84 68 34 19
July 5 ..... 60 39 70 76 72 68 86 71 80 66 26 17
July 6...... 62 42 59 53 72 63 86 70 84 68 30 21
July 7 61 38 67 64 74 64 96 73 78 56 45 24
July 8 .. 88 59 92 44 83 53 97 69 130 82 42 29 R
July 9 ....... 82 3 85 46 78 52 86 62 96 61 36 21
July 10 70 28 75 51 79 49 95 59 90 44 30 16 0
July 11 .......... 68 30 70 53 85 65 103 95 80 61 32 11
July 12... 41 27 72 46 55 38 103 90 89 51 18 8
July 13 ......... 34 11 51 39 54 38 93 57 97 57 27 5
July 14 ...... 34 14 27 8 30 12 35 20 53 23 7 13
July 15 .. 27 20 38 29 52 24 65 33 33 17 4
July 16 28 15 27 13 27 7 53 24 41 13 14 4
Totals ..... 1203 1032 1360 1360 1433 1344 1687 1470 1664 1364 593 ] 722
Average No.
Blossoms
per Plant .... 18.2 16.6 16.5 16 15.7 13.8 18.7 17.09 17.7 16.4 18.9 16.6
*All squares removed on June 7.






Bulletin 165, Improved Method Boll Weevil Control 21

Table 2 shows that the non-stripped plants, producing blos-
soms from June 8 to July 16, did not produce as many to the
plant as did the stripped plants, the latter having only from
June 20 to July 16 in which to fruit. When the stripped plants
began to square they soon caught up with and passed the non-
stripped plants in the rate of blossoming. The non-stripped
plants during this period were forming seed and lint in the
bottom bolls and were not producing squares to any marked ex-
tent.
Reference to Table 3 shows that the stripped plants produced
a daily average of .626 blossoms to the plant, while the non-
stripped ones produced an average of .41 blossoms.
TABLE 3.-AVERAGE NUMBER OF BLOSSOMS TO THE DAY ON STRIPPED AND
NON-STRIPPED PLANTS

p




454 449 28 39 i 7,940 7,292
Average, daily ............. ........... 283 187
Daily average to the plant.......--..............-- ........... .62 | .41

Table 4 shows the number of blossoms produced each day on
the total of 454 plants which were stripped of their squares on
June 8 and on the total of 449 plants which did not have the
squares removed. For purposes of ready comparison, the ave-
rage blossoms to the plant for each day, in case of both stripped
and unstripped plants, is also shown. It will be noted that from
the time (June 20) the stripped plants began putting on squares,
only eight days elapsed until these plants were producing squares
faster than the plants from which no squares had been removed.
It is also interesting to note that the blossoming rate of the
stripped plants did not fall off as quickly as did that of the check
plants. The daily blossoming rate of these two groups of plants
is shown graphically in figure 1.
On July 16 the bolls on both these lots of plants were counted.
It was found that on the 454 plants which had been stripped of
their squares on June 8 there were 4,846 bolls, or an average of
10.7 bolls to the plant; while on the 449 plants which had not
been stripped there were 4,549 bolls, or an average of 10.1. This
presaged a slight difference in production. The stripped plants







Florida Agricultural Experiment Station


yielded at the rate of 841.4 pounds of seed cotton to the acre
and the non-stripped yielded at the rate of 769.5 pounds, a dif-
ference of 71.9 pounds in favor of the former.

TABLE 4.-DAILY AVERAGE OF BLOSSOMS TO THE PLANT ON STRIPPED AND
NON-STRIPPED PLANTS


Number of Plants


C)
4-,

June 8 ........
June 9 .----.
June 10 ..........
June 11 .........
June 12 ..-......
June 13 ........
June 14 .........
June 15 .........
June 16 ..........
June 17 ..........
June 18 ........-
June 19 ........
June 20 ..........
June 21 -.........
June 22 .........
June 23 ..........
June 24 .......--
June 25 ...-.....
June 26 .........
June 27 .........
June 28 ..........
June 29 .........
June 30 .........
July 1 .......
July 2 ........
July 3 ..........
July 4 .........
July 5 .......
July 6 ..........
July 7 ..........
July 8 .........
July 9 .........
July 10 .......
July 11 ...--....
July 12 .........
July 13 .........
July 14 ......
July 15 ....
July 16 ........


449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
4-4



449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449
449









449


7


30
121
460
475
427













539
439
394
14393
21
53247
463

439
438
37894
35693
42186
263
193



7,940
.-- ..... ..- ..-
- -- -
-----------------
-----------------
- - --.. .
.....------------
































T,940


Number of Blossoms


a
a)









- .... .
- -- -- -- -









.015
.004
.037
.07
.27
.30
.32
.25
.47
.76
1.00
1.04
.94
1.18
.96
.86
.86
.92
1.17
1.01
.96
.96
.83
.78
.40
.58
.42


43
57
53
61
-i->
C


43
57
53
61
65
75
84
89
102
96
102
95
92
54
71
90
221
165
156
124
172
291
412
440
355
445
359
337
317
319
336
277
247
315
260
207
150
142
76
7,352


In this field of one acre, no steps other than the stripping of
the six rows had been taken to control the weevil, with the
result that a heavy infestation was reached by the middle of


U'

CaS




.09
.12
.11
.13
.14
.16
.18
.19
.22
.21
.22
.21
.20
.12
.15
.20
.49
.36
.34
.27
.38
.64
.92
.98
.78
.99
.79
.75
.70
.71
.74
.61
.55
.70
.58
.46
.33
.31
.16







Bulletin 165, Improved Method Boll Weevil Control 23

July and many of the smaller bolls on the stripped plants were
injured by the weevils. Had treatment for control of the weevil
been given to the entire field it is likely that many of these bolls
would have fully matured, thus increasing the difference in
yield.



110



,.,o i \ !
Si I i








S.80 '


.70 C "''

Q.6o I

s :-I

Si :





.30 *


.20


.10
./5 / 1


oo'
5 '0o /5 zo Es5 30 5 /0 /5


Fig. 1.-Chart showing blossoming rate of stripped (heavy line) and non-
stripped (dotted line) cotton plants (original)







24 Florida Agricultural Experiment Station

The results of this experiment are presented as showing that
the removal of the first squares of the season not only does not
reduce the normal crop but actually seems to increase it; and
that such a result would apparently follow square-stripping as
described, even if there were no boll weevil infestation.
SETTING A BOTTOM, MIDDLE AND TOP CROP IN 30 DAYS
The data just given point to one of the most satisfactory
phases of the improved method of boll weevil control. Following
the removal of the squares from the plants on June 7, rapid
growth took place for a few days, which in turn was followed
by the appearance of squares from bottom to top.
Therefore it appears that by removing the first few squares,
one may force the plants to set the three "crops" at approxi-
mately the same time, or between about June 20 and July 20.
Figure 2 shows the profuse and uniform development of squares
under these conditions.
RELATION OF SQUARE REMOVAL TO MATURITY OF CROP
As would be expected, removal of the first squares of the
season results in the appearance of the first open cotton from
ten to fifteen days later than would otherwise be the case. There-
fore, as practically all the bolls for the crop are set between
about June 20 and July 15 and as each boll opens in approxi-
mately 40 days, it follows that the entire crop opens between
about July 30 and September 1.
This condition not only permits the cotton grower to harvest
his crop with two, or at most three, pickings, but it also enables
him to complete the harvest in ample time to destroy all the
cotton plants by October 1-a most effective measure for re-
ducing the number of weevils that can go into hibernation and
that must be dealt with the following spring.
RELATION OF THE WEEVIL'S LIFE HISTORY TO CONTROL
An accurate knowledge of the weevil's life history under Flor-
ida conditions is very necessary to a satisfactory application of
the control measures. A bulletin8 by the writer, published in
1921, contains detailed accounts of the insect's life history, as
determined by observations made in cotton fields in Madison
County. Substantially, the life history was found to be as fol-
lows:
'Bulletin 926, U. S. D. A.






Bulletin 165, Improved Method Boll Weevil Control 25

The boll weevil passes the winter as an adult. With the first
warm days of spring the weevils gradually emerge from their
hibernating places in moss, leaves, trash, etc., and seek the cot-
ton fields. The adults feed first upon the leaves of the young
cotton plants and then upon the growing tips until the first
squares appear. With the development of the squares, eggs are
immediately deposited in them by the female weevils.
Under the temperatures prevailing in North Florida in early
summer, an average of 21.9 days elapses between the depositing
of the egg in the square and its development, thru larval and
pupal stages, into the adult. The female does not become sex-
ually mature and capable of depositing eggs until an average of
7 days after she emerges from the infested square. For ex-
ample, a total of 30 days must elapse before an egg, deposited on
June 5, can develop into an adult female capable of depositing
eggs.


Fig. 2.-Cotton plant, with leaves removed, showing extent of fruiting 22
days after removal of i" squares (original)






































Fig. 3.-Typical surroundings of a cotton field in Madison County, showing favorable hibernating quarters for the boll
weevil (field No. 5, Sanders Plantation)






Bulletin 165, Improved Method Boll Weevil Control 27

Certain climatic conditions, such as prolonged dry weather,
may operate to greatly lengthen this period but, for all practi-
cal purposes, 30 days may be considered as the necessary time
for the development of a generation of weevils; and not 10 to
15 days, as many cotton planters have come to believe.
Males and females are produced in about equal numbers, the
male being slightly smaller than the female as a rule. Both
males and females feed on cotton bolls and squares, the puncture
by either sex causing the square to flare and drop off.
The female usually deposits only one egg in a square but in
late summer, when maximum infestation is reached and all
squares are punctured, several are frequently deposited in a
single square.

HIBERNATION
Where the cotton plants are allowed to remain standing, a
few weevils may develop during the winter months from squares
and bolls which became infested late in the season. However,
with the advent of cool weather, or the first killing frost, the
bulk of the weevils leave the cotton field and fly in various direc-
tions. Sooner or later they find shelter, as along fencerows or
in the woods. Spanish moss, suspended in the forest trees, af-
fords them most excellent protection during the winter. Typi-
cal quarters for weevil hibernation are shown in figures 3 and 4.
The weevils are frequently active during the winter in Florida.
In fact, hibernation is seldom complete under Florida condi-
tions. The number of weevils surviving the winter in Florida
is possibly as great as anywhere in the South. An extensive
hibernation test in cages at Madison in 1918-19 indicated that
an average of 7.54 percent lived thru the winter.
Emergence from hibernation often commences in Florida dur-
ing January. The weevils come out of their winter quarters
gradually, the rate of emergence depending largely upon the
temperature and amount of rainfall.
As shown elsewhere in this paper, the emergence from hiber-
nation in Florida is, for all practical purposes, complete by about
June 5. A few stragglers may emerge after this date but they
are too few to cause injury of any consequence during early
and mid-summer.






Florida Agricultural Experiment Station


THE EXPERIMENTS OF 1922
As a result of the experimental work mentioned in the pre-
ceding pages the idea was conceived of combining square-strip-
ping and poisoning as a means of controlling the weevil and
increasing the yield of cotton. In order to test this theory under
farm conditions, plans were made and carried out for making
observations on relatively large scale field-tests during 1922.
These experiments were located near the towns of Madison,
Live Oak, Wellborn, Gainesville and Hawthorne. Both upland
and sea-island cotton were included in the tests. Only the
results with upland cotton are discussed in this bulletin, as the
acreage of treated sea-island was too small to permit of reliable
conclusions.
All of the tests were located in fields where conditions were
apparently very favorable for the boll weevil.
Briefly stated, the object of these experiments was to deter-
mine whether removal of the first squares, followed immediately
by one application of poison, would dispose of practically all
weevils in the field and, if so, whether weevil damage thereafter
could reach the point where production of cotton would be
seriously interfered with.
It may be stated at this point that the removal of all squares
on or after June 5, followed by one thoro application of lead
arsenate or calcium arsenate at the rate of from five to seven
pounds to the acre, resulted in not more than an average of one
weevil to the acre being left in the fields. Even if this weevil
should happen to be a female and commence depositing eggs
immediately, the first generation of her offspring would not
reach maturity and deposit eggs before about July 5. The num-
ber of squares punctured by this generation would hardly offset
the natural shedding of the plants. The second generation could
not mature before about August 5 and, while it is granted that
this generation might consist of many weevils, it must be re-
membered that the Florida crop of short staple is, by this date,
"made" and sufficiently matured that practically no damage
from the weevil can take place.
MANNER OF MAKING FIELD TESTS
In testing any method of control, it is essential that the field
conditions be as nearly typical as possible. It is only by such
field experiments that profit or loss, resulting from the control
operations, can be determined.





































Fig. 4.-Moss-covered oaks at edge of cotton field. Boll weevils survive the winter in large numbers where such condi-
tions exist (original)






Florida Agricultural Experiment Station


In the experiments herein described, certain fields were treated
to control the weevil while others were left untreated for com-
parison. Not all fields were treated on the same date, however.
The fields, both treated and non-treated, were selected so that
surrounding weevil-hibernating quarters, drainage and soil con-
ditions would be as nearly alike as possible.
Measurements were made of all fields and plots. In Madison
and Suwannee Counties these surveys were made by Chas. S.
Wadsworth', of Madison. The cotton picked from each field was
kept separate and carefully weighed and recorded. Arrange-
ments were made with the owners to plant the fields on the same
dates as far as possible, and to cultivate them in the same man-
ner thruout the season.
MANNER OF APPLYING THE POISON
The machine used in our experiments was a hand duster of a
well-known make, which forces the poison thru the nozzle with a
current of air. On account of its being operated by hand the
nozzle can be manipulated in such a manner as to force some of
the poison into the terminal bud of each plant.
Other methods of applying the poison, such as dusting from
sacks and distributing "broadcast," were tried but none gave
satisfactory results. On account of the boll weevil's habit of
feeding in the terminal buds when there are no squares present,
any machine used for applying the poison must in some manner
force the poison into these feeding places.
INFESTATION RECORDS
The percentage of punctured squares in a cotton field offers
reliable data for determining the extent of infestation by the
weevil. If only a small percentage of the squares are punctured
during June and July, a good crop, all other things being equal,
may be expected. On the contrary, a heavy infestation during
early summer is always followed by a greatly reduced yield.
Removing or stripping the squares from the plants early in
June results in the absence of all squares for a few days and of
punctured squares for a considerable period. However, within
five to seven days after stripping, new squares take the place
of those removed. In the method of control used in these experi-
ments, stripping is followed by poisoning. Any weevils not de-
stroyed by this dual treatment proceed to attack these new
'Registered Civil Engineer No. 106, State of Florida.






Bulletin 165, Improved Method Boll Weevil Control 31

squares. The percentage of infestation following the treatment
shows its effectiveness as well as the rate of increase of any
weevils that have not been destroyed.
For convenience, the records of infestation used in this bul-
letin were based upon an examination of 200 squares in each of
three representative places in each field at intervals of 15 days.
All squares on a plant were examined and counted and when
200 squares had been inspected the number of weevil-punctured
ones was recorded. This count was repeated until a total of 600
squares had been examined in each plot.
The first examinations were deferred until July 1 in order
that any weevils missed by the control operation might have
time to establish an infestation that could be quite readily
found.
HOW "PROFIT" OR "LOSS" IS DETERMINED
Any successful method of controlling the weevil must not only
increase the yield but must also result in sufficient increase to
more than offset the cost of using it. The cost of removing the
squares from the plants, of the labor for applying the poison and
of the poison itself must be deducted from the value of the in-
creased production to determine accurately what has been ac-
complished by using the control method.
In the experiments described herein the value of labor by
women and children in removing squares is estimated at the
prevailing local rate of $.60 a day of ten hours or $.06 an hour,
while the adult male labor used in applying the poison is esti-
mated at $1 a day or $.10 an hour. The wages paid for ordinary
farm labor vary in different sections of the state and this will,
of course, cause a corresponding variation in the profit secured
by controlling the weevil in this way,
The cost of calcium arsenate is calculated at $.10 a pound.
This is about the maximum retail price for this material in
Florida during 1922. It is to be expected that the price will
increase slightly in the near future.
Altho we have not included the cost of using dust guns in
estimating the cost of weevil control in the experiments herein
described, this item must be considered. A good hand duster for
applying the poison is absolutely essential. A good one can be
bought for about $10 and with proper care and handling will last
several seasons. Under average conditions the annual acre cost
for dust-gun investment and depreciation should not exceed $.25.






Florida Agricultural Experiment Station


PLOT EXPERIMENTS
EXPERIMENTS ON THE SANDERS PLANTATION
These experiments were located on the E. Sanders plantation
five miles southwest of Madison, on Orangeburg sandy soil. Ac-
cording to all information available, the land had been in culti-
vation from 50 to 60 years.
Hibernating quarters for the boll weevil were abundant, the
plantation being dotted with large trees heavily laden with
Spanish moss, as shown in figure 4. Cotton had been grown on
the plantation in 1921 and some of the 1922 plots were located
in fields which were in cotton the preceding year. No fertilizer
was used.
With the exception of treated field No. 5, all the fields were
planted, the last week in March, to Lewis 63, an upland variety
bred by the Georgia State Board of Entomology for its resistance
to wilt'1. Field No. 5 was planted to mixed seed of the upland
type.
The planting, cultivating and picking of all fields were done
by a negro tenant, Jake DeLaughter, the weighing of the cotton
being supervised and checked by the writer or an assistant.
Treatment for control of the boll weevil was supervised by the
writer. The untreated cotton used as a check was grown by
a colored tenant, Boswell Johnson.
In the experiments there were five cotton fields treated to
control the weevil and one left untreated for comparison.
In all of the plots, except the check the plants were stripped
of all squares May 29 to 31 and had calcium arsenate applied
June 1 and 2.
Inspections of all fields were made by Plant Board employees
on July 1, July 15, August 1 and August 15 and the percentage
of weevil infestation determined. The results of these exami-
nations are given in Table 5.
Field No. 1
Field No. 1 consisted of 1.85 acres. The squares were picked
from the plants on May 29 and the poison applied on June 1.
The cost of treatment was:
Labor, picking off squares, 12 hours at $.06 .................. .......... $ .72
Labor, applying poison, 4 hours at $.10.................. ... .......... .40
Calcium arsenate, 9.25 lbs. at $.10...........-.. ....... ... ..... .93
Total -...-- ..-- ........ ............. .... ......$2.05
Cost, an acre....... .. -- ................... .....-.... ......... $1.11
"0Neocosmospora vasinfecta (Atk.), Smith.







Bulletin 165, Improved Method Boll Weevil Control 33

The treated plot of 1.85 acres produced 660 pounds of seed
cotton or 356 pounds to the acre, while the check plot of 3.27
acres produced 350 pounds or an average of 107 pounds to the
acre. This difference in yield is shown as follows:
Treated .......... ..... ..... ..... .......... ... 356 lbs. to the acre
Non-treated ........- ...-. ............ .. ....- 107 lbs. to the acre
Increase in production, treated field.......... 249 lbs. to the acre
On the basis of current prices, this increase in yield is valued
as follows:
83 lbs. lint at $.21 a pound .......... ............. ............... $17.43
166 Ibs. seed at $32 a ton ............... .................. ...... 2.65
Total ..-........... ................ ..... .... $20.08
The cost of treatment was $1.11 to the acre and by deducting
this from the value of the increase in production we find that a
profit of $18.97 to the acre resulted from the control operation.
The treated plot had a much poorer stand than the check plot
and, on account of heavy rains following the removal of the
squares on May 29, application of the poison was not possible
until June 1, whereas for best results it should have been applied
the same day.
Field No. 2
This field contained 3.89 acres and was located about one
hundred yards south of the plot just described. Along its east
side was a highway shaded by moss-covered trees, while under-
brush and large trees occurred around a pond just west of the
field.
The squares were picked from the plants on May 30 and poison
applied on June 2. The cost of the dual treatment was:
Labor, picking off squares, 38.5 hours at $.06........................... 2.31
Labor, applying poison, 8 hours at $.10.......................... ......... .. 80
Calcium arsenate, 19.25 Ibs. at $.10................. ......... ....... ........ 1.93
Total ........- .........- ...-..-.. -----------.....-. .... ..... ......$5.04
Cost, an acre..... .......- ..........- ................ ...................- $1.30
The treated field produced 2,038 pounds of seed cotton or 524
pounds to the acre. A comparison between it and the check plot
is thus made:
Treated ...... .................. ..... .... ............ 524 Ibs. to the acre
Non-treated ................ ..... -- ......- ... ..-.- 107 Ibs. to the acre
Increase in production, treated field...........417 Ibs. to the acre
The value of the increase in cotton secured, due to the control
operations, was:







Florida Agricultural Experiment Station


139 lbs. lint at $.21... ....... ......... ................... ....... ..... $29.19
278 lbs. seed at $32 a ton----.............-.................. .......... 4.44
Total ...------.......... ..........--........-- ....$33.63
Deducting from this the cost of treatment ($1.30), the profit
from controlling the weevil in this experiment was $32.33 to
the acre.
Field No. 3
Field No. 3 consisted of 2.02 acres and adjoined Field No. 2.
All squares were removed on June 1 and poison applied on
June 2. The cost of this work was as follows:
Labor, picking off squares, 20 hours at $.06 ......................... $1.20
Labor, applying poison, 4 hours at $.10.....---................ .... .40
Calcium arsenate, 10 lbs. at $.10 ----..........-.- --.... --.......... 1.00
Total --------. ----..----------------- ...----.$2.60
Cost, an acre- ...-.....-......... .............-- $1.28
The 2.02 acres produced 1,044 pounds of seed cotton and its
production is compared with that of the check in the following
manner:
Treated .................... ...... .... .. ........... .. .516 lbs. to the acre
Check ...-------------.. ... ... ............ ... ...... 107 lbs.. to the acre
Increase in production, treated field...-........409 lbs. to the acre
The value of this increase is arrived at thus:
136 Ibs. lint at $.21--- ---.. ............. ..... $28.56
273 lbs. seed at $32 a ton. .......................... ... 4.36
Total --... -- ..................... .. ..... ..... $32.92
By deducting the cost of treatment ($1.28) from the above
figure it is seen that control of the weevil in this field gave a
profit of $31.64 to the acre.

Field No. 4
The field contained 3.76 acres and was surrounded by corn
fields, tho not over 200 yards from good weevil-hibernating
quarters. A heavy rain storm shortly after planting resulted in
severe damage and the stand secured in this field was later
determined by an actual count of the plants to be only 44 per-
cent of normal.
The squares were stripped from the plants on June 1 and the
poison applied June 2. The cost was:
Labor, picking off squares, 37 hours at $.06---.................-..........$2.22
Labor, applying poison, 8 hours at $.10-...............-- ............ .80
Calcium arsenate, 19 lbs. at $.10-.........--.... ...........- 1.90
Total ------ -.....- .. ---....... ........$4.92
Cost, an acre .. ----- ..... ............... .. ........ $1.31







Bulletin 165, Improved Method Boll Weevil Control 35

Despite its poor stand, the treated field produced 857 pounds
of seed cotton or 228 pounds to the acre. In making the following
comparison between its yield and that of the check it should be
remembered that the check plot had about 90 percent of a nor-
mal stand.
Treated .-........... ............ .............. 228 lbs. to the acre
Non-treated ....................... .............. 107 bs. to the acre
Increase in production, treated field .......... 121 lbs. to the acre
The value of this increase is arrived at in this manner:
40 lbs. lint at $.21.- ......---....-... .. -.. ..... ..--- --- .$8.40
81 lbs. seed at $32 a ton.................................. .. 1.29
Total ........................... ...-- .... $9.69
Deducting the cost of treatment ($1.31), we see that control
of the weevil gave a profit of $8.38 to the acre, even tho the
field receiving the treatment was handicapped by storm damage
and a very poor stand.

Field No. 5
The conditions under which the improved method of control
was tested in this plot were unusually severe. No particular
variety of cotton was used: the tenant had merely planted
"cotton," mixed seed of unknown varieties. The field, containing
2.24 acres, was in the form of a rectangle and was bordered on
the west by a dense swamp (see figure 3) which had afforded
ideal hibernating quarters for the weevils produced in cotton
grown on the same field the previous year. The land in this
field is rolling and perhaps slightly more fertile than fields 1 to 4.
At the time the first squares appeared the colored tenant was
much discouraged on account of the large number of weevils
present and asked that he be allowed to plow up the cotton.
The squares and 730 visible adult weevils were picked from
this plot on May 29, to say nothing of those which may have
been within the involucres (or shucks) of the squares. No at-
tempt was made to ascertain the total number of weevils removed
in the square-picking process, but it is likely that fully 1500
were taken off. Poison was applied June 1. The cost of picking
off squares and applying the poison was as follows:
Labor, picking off squares, 30 hours at $.06 ...............................$1.80
Labor, applying poison, 5 hours at $.10................- ........... .50
Calcium arsenate, 15.6 lbs. at $.10 --- ....................... 1.56
Total ...... ........... ...... .............$3.86
Cost, an acre .. ..-- .. ...... ...-....... $1.72







36 Florida Agricultural Experiment Station

The treated field produced 850 pounds of seed cotton or 379
pounds to the acre, which was remarkable in view of the fact
that there was hardly 50 percent of a stand. It was the con-
sensus of opinion of those who followed the experiment carefully
that, with the enormous number of weevils present in May, this
field would have produced practically no cotton had the weevil-
control treatment not been given. Its actual yield is compared
with that of the check plot in the following manner:
Treated ...... ..... ... ......... ... ... .... 379 lbs. to the acre
N on-treated ................. ............... ....... ...... 107 lbs. to the acre
Increase in production, treated field ......... 272 Ibs. to the acre
The value of the increase is thus determined:
90.6 lbs. lint at $.21................ -......-..- .. $19.02
181.4 lbs. seed at $32 a ton................................. 2.90
Total .......... -.. ......... .. ..... $21.92
From the value of this increase should be deducted the cost
of treatment ($1.72), which gives $20.20 to the acre as the
profit resulting from controlling the boll weevil.

Infestation Record, Sanders Plantation
The data concerning the percentage of infestation by the
weevil in the check field and the five treated fields on the San-
ders plantation is presented in Table 5.

TABLE 5.-PERCENTAGES OF INFESTATION, SANDERS PLANTATION
July I July 15 Aug. 1 Aug. 15
Check field ................... 14.00 70.00 89.9 100.0
Treated fields:
No. 1 .................. ..... 0.8 11.0 57.0 85.0
No. 2 ....................... 0.9 0.12 66.0 86.0
No. 3 ........................- 0.01 3.6 68.0 79.0
No. 4 .......................... 0.01 5.0 80.0 91.0
N o. 5 .........................- 0.4 13.0 88.0 95.00
Average infestation,
treated fields .............. 0.4 6.5 75.1 87.2
In practically all of the fields described herein, it will be
noted that the infestation on August 1 was much higher than
on July 15. The reason for this increase lies in the fact that
the cotton in nearly all fields showed a very determinate habit
of growth and that the crop was "made" by the middle of July.
After this date nearly all the squares and, in many cases, the
leaves, were shed. The result was a concentration of the weevils
on a much smaller number of squares and this operated to in-
crease the percentage of infestation.







Bulletin 165, Improved Method Boll Weevil Control 37

TABLE 6.-SUMMARY OF RESULTS, SANDERS PLANTATION





2s 333 1.30 32.33
4 15


C) C C) 5 i t5 Cc < '

Checkl 3.27 350 ...- ... 107 .... I .......-............ ...-...... .. ........... I-....
1 1.85 660. 356 107 249 232 $20.08 $1.11 $18.97
2 3.89 2038 524 107 417 389 33.63 1.30 32.33
3 2.02 1044 516 107 409 382 32.92 1.28 31.64
4 3.76 857 228 107 121 113 9.69 1.31 8.38
5 2.24 850 379 107 272 254 21.92 1.72 20.20
Totalslj_13.76 J 5449 -..--. ...--|----- ..-.. -.. .... ... ... ...-.-...- .. .. 1. ..- ..
Averages...........1-I| 396* 107 1 289 270 23.30 *1\ 1.34 | 21.96
*Obtained by dividing total production by total acreage.
**Value of the 289 pounds.
EXPERIMENT BY A. HODGE

This experiment was of peculiar interest in that it was carried
out by Mr. Hodge, a practical farmer living about four miles
northeast of Madison without any supervision or help other than
an oral description of the principles involved and the manner
of giving the treatment.
Mr. Hodge had two fields of cotton. He treated one to control
the boll weevil and left the other untreated.
The field selected for treatment contained 5.73 acres of high,
well-drained Norfolk sandy soil. During the last week in March
the field was planted to Lewis 63. One hundred pounds to the
acre of an equal mixture of kainit and acid phosphate was ap-
plied at the same time.
Mr. Hodge had been advised to begin the weevil treatment
on June 5 but, finding the hibernated weevils abundant in his
field, he began May 25 to pick the squares and visible weevils
from the plants. He completed this work on June 4. On June 5
he applied poison to 3.5 acres and, finding many weevils present
(due to his having commenced stripping before all weevils were
out of hibernation), he decided to again strip the squares from
the remaining 2.23 acres. Therefore, this part of the field was
given its second stripping on June 5 and 6 and the poison ap-
plied on these dates.
Mr. Hodge states that he and his two small boys did all of the
square stripping in two days and that he applied four pounds
of calcium arsenate to the acre in about one day. Upon this















/.<^-
4-
'4.


-4


Fig. 5.-Normal cotton production secured by A. Hodge as a result of using the improved method of boll weevil control
(original)


t







Bulletin 165, Improved Method Boll Weevil Control 39

basis, the cost of treating his field was approximately as fol-
lows:
Labor, picking off squares .... ....... ........ ..--..---------------$2.50
Labor, applying poison...... ......... ...-.......---- -- 1.00
Calcium arsenate, 22.9 lbs. at $.10........................ ...- 2.29
Total ....... ..... .......... --------------$5.79
C ost, an acre .............. ............................ .--...- .- $1.01
Mr. Hodge reports that in stripping the squares he captured
67 adult boll weevils in addition to whatever number may have
been concealed within the squares. Following the stripping and
application of poison Mr. Hodge examined plants in all parts of
the field and found three weevils had been missed.
The 3.5 acres which were stripped of squares once yielded
1,683 pounds of seed cotton or 481 pounds to the acre. The 2.23
acres of cotton (which were stripped twice) produced 1,317
pounds, or 590 pounds to the acre. The entire field (5.73 acres)
produced 3,000 pounds, or an average of 523 pounds to the
acre. The appearance of this field at picking time is shown in
figure 5.
The non-treated field, planted and grown by Mr. Hodge for
comparison with the above contained .52 acre and yielded 58
pounds of seed cotton, or 111 pounds to the acre.
The following comparison between the yield of all the treated
cotton, on the one hand, and of the non-treated on the other,
may therefore be made:
Treated .................................. -- -- ........... 523 lbs. to the acre
Non-treated ....................l--.. ............. ........111 Ibs. to the acre
Increase in production, treated field............412 lbs. to the acre
The value of this increase is found as follows:
137.3 lbs. lint at $.21 ......- .. .... ... .............. -$28.83
274.7 Ibs. seed at $32 a ton ............................. ........ 4.39
Total ---............. ......... --. $33.22
From this must be deducted the cost of treatment, estimated,
according to Mr. Hodge's figures, at $1.01 an acre, leaving $32.21
an acre as the profit which Mr. Hodge derived from controlling
the weevil by this method.
Mr. Hodge states that the crop of upland cotton produced in
his treated field was fully the equal of any he ever produced
prior to the advent of the boll weevil.
A TEST IN SUWANNEE COUNTY
The method of weevil control described on preceding pages
was tried by H. Wimberly in a small field of Meade cotton on






Florida Agricultural Experiment Station


his farm 10 miles southwest of Live Oak. He is an extensive
grower of sea-island cotton and his entire acreage was planted
to sea-island with the exception of the field of Meade which re-
ceived treatment.
This could hardly be considered a true experiment, inasmuch
as there was no check or non-treated field for comparison with
the treated one. It was more in the nature of an attempt to find
out how much of a crop could be obtained in the face of the
weevil infestation in that locality.
The field was on Norfolk sandy soil, well-drained, had been in
cultivation for several years and was considered rather poor.
The cotton was planted on March 20 and about a hundred
pounds to the acre of a home-mixed commercial fertilizer ap-
plied.
On May 29, under supervision of the writer, all squares were
picked from the plants and calcium arsenate was applied the
following evening at the rate of five pounds to the acre. Records
of the cost of treating this field are incomplete but approxi-
mated $1.50 to the acre.
Counts were made of squares in this field at intervals of 15
days during July and August and the following data obtained
as to the weevil infestation:
Date Infestation,
percent
July 1 ...............- ----- ... -------...... 2.0
July 15 ...........-.......... .......--- ......----.--.. .----- 9.6
August 1 ................-.. .. --....... ---.. ------.. ----59.0
August 15 ..................... ..........------ --------88.0
The above record shows that almost complete freedom from
weevil damage was secured thru June and well into July.
This field contained 2.55 acres. The owner's records show a
production of 1,560 pounds of seed cotton, an average of 611
pounds to the acre.
A TEST IN ALACHUA COUNTY
This was not a true experiment as, like the test just described,
there was no check or non-treated field for comparison. It was,
rather, an attempt to produce a crop of cotton on very poor soil,
using the method of weevil control under investigation. The
results of this test are of unusual interest in that the number of
weevils in the field prior to treatment was definitely known. No
cotton had been grown in the vicinity the year before and
weevils were purposely placed in the field to insure a heavy in-
festation.






Bulletin 165, Improved Method Boll Weevil Control 41

The field consisted of a two-acre plot on the grounds of the
University of Florida Experiment Station. The land is sandy,
well-drained and very deficient in plant food. Six hundred
pounds to the acre of 8-3-3 fertilizer was applied on March 9,
and DeSoto cotton planted on March 15.
Five hundred fifteen boll weevils were liberated in this two-
acr~ cotton field between May 29 and June 2, furnishing an in-
festation which compares favorably with that usually found in
the average cotton field at that time of year.
Owing to .the experiments in other counties requiring the
writer's attention, treatment of this field for weevils could not
be given until June 8. As this season's experiments have shown,
this field was also planted earlier than it should have been. As
a result, the plants were larger and more advanced than was
desirable and some bolls had already formed. However, on this
date all squares, bolls and blossoms were stripped from the
plants, and calcium arsenate applied. Because of the large size
of the plants, it was necessary to apply the poison at the rate
of 11 pounds to the acre. The large amount of fruitage removed
and of poison required made the cost of treatment ($6.64 to the
acre) abnormally high.
Because an employee of the Experiment Station failed to carry
out instructions, this field received no cultivation from June 8
to June 30, the most critical period in the formation of the crop.
By June 30 the plants were badly affected with bacterial wilt"
("rust"), appeared to have reached their full growth and had
set an average of only one boll each. Any stimulation that may
have resulted from the square-stripping had, by this time, ap-
parently spent itself. At this stage nitrate of soda was applied
to the field at the rate of 100 pounds to the acre and cultivation
was resumed. The recovery of the plants was remarkable and
during July they produced squares and blossoms rapidly.
Altho an examination of 300 picked and counted squares, on
July 1, did not reveal any infestation, a few punctured squares,
apparently the work of a single weevil, were found by carefully
examining the entire field. It was evident that out of the 515
weevils positively known to be in the field prior to treatment,
not more than one or two escaped.

1Bacterium malvaceurum E. F. Sm.







































Fig. 6.-More than one-thiro )f a bale to the acre on poor sandy soil. Made possible by controlling the boll weevil.
Grown on Experiment Station farm at Gainesville (original)







Bulletin 165, Improved Method Boll Weevil Control 43

The examinations made during July and August showed the
progress of infestation to have been:
Infestation,
Date percent
Ju ly 1 ...... .. ......... .... ..... ............ 0.0
July 15 ............. ........ .... ......... .... ................. 6.2
A ugust 1 .... ....... .... .......... ........... .. ...... ........ .... 60.0
A ugu st 15 ...................... ........................ ...............90.0
The crop was picked during September under the supervision
of A. W. Leland, farm foreman of the Experiment Station, and
amounted to 1,100 pounds of seed cotton, or 550 pounds to the
acre. The appearance of this field at picking time is shown in
figure 6.
As already stated, this could not be regarded as a true experi-
ment, as there was no way to ascertain the profit derived from
the treatment. The test did show that, even on the poorest
sandy soil, a fair crop of cotton can be made in spite of heavy
weevil infestation. Practically the entire crop was made after
July 1. Despite the fact that the field received no cultivation for
18 days at the most critical period, the yield secured would have
been considered excellent on this type of land prior to the
advent of the boll weevil.
The account of this test is given here because the observa-
tions corroborate, in some measure at least, the conclusions
reached in the experiments prope"

A PLANTATION TEST
The reader who has followed the accounts, on preceding pages,
of the experiments in relatively small cotton fields may be in-
clined to wonder whether the method of boll weevil control used
therein is also applicable to large fields or under conditions which
exist on typical cotton plantations.
The first reply to this question is that experiments made upon
small areas, where all conditions are under the personal obser-
vation of the experimenter and where all operations can be quite
definitely controlled, afford a much more crucial test than ex-
periments made upon relatively large acreages. If a principle
or method is correctly tested upon a small scale and found ade-
quate, it may confidently be relied upon when used more exten-
sively.
However, it was anticipated that this question would be asked
and preparation was, accordingly, made to secure data with which
to answer it. The opportunity came thru the courtesy of S. A.






Florida Agricultural Experiment Station


Smith of Madison, who offered for experimental purposes the
fields planted to cotton on his plantation in 1922.
This plantation, containing about 3,000 acres and located five
miles south of Madison, is typical of many occurring in Florida
in that most of the cleared land has been in cultivation for many
years and is more or less impoverished. Little rotation of crops
has been practiced. The plantation is divided into small areas,
each of which is rented to a share tenant. In addition, the al-
most total destruction by the boll weevil of all cotton crops at-
tempted on this place since 1916 assured a weevil infestation
heavy enough to satisfy the most exacting requirements.
Numerous bay-heads and areas of dense forest abound on
the plantation. Trees in the forest, as well as those around
houses and along the fencerows and roads, are heavily laden
with Spanish moss. These areas, together with uncultivated
fields grown up to grass and weeds, afforded ideal hibernating
quarters for the weevil.
Cotton grown in various fields on the plantation during 1921,
with no effort made to destroy any of the cotton plants in the
fall, furnished an abundance of weevils to enter hibernation and,
consequently, large numbers to attack the crop this spring. The
entire cotton acreage on the plantation in 1921 did not average
over 50 pounds of seed cotton to the acre.
The land is more or less rolling, well-drained and mostly
Orangeburg sandy loam. According to the owner, this land is
capable of making, without fertilizer, an average of 400 pounds
of seed cotton to the acre.
All cotton on the plantation in 1922 was grown by tenants or
"half-croppers," each planting, cultivating and harvesting his
own field. Owing to the heavy weevil damage experienced in
preceding years, the owner of the plantation did not deem it
safe to make advances of fertilizer to the tenants; but he did
secure for them a supply of Lewis 63 seed.
Past experience with cotton growing under boll weevil con-
ditions had not made the tenants at all enthusiastic and they
did not exert themselves to secure satisfactory stands, or even,
in some cases, to give their cotton reasonably good care and
cultivation. With one exception the tenants were negroes.
The conditions under which the experiment was undertaken
were, therefore, in every way representative of those existing
on a typical plantation of the kind formerly given over mainly
to the production of cotton under the tenant system.






Bulletin 165, Improved Method Boll Weevil Control 45

The tenants were induced to plant their cotton during the
last week in March, as it was believed that this would result
in the plants being ready for treatment when practically all boll
weevils had emerged from hibernation.
The work of removing squares and applying poison was done
by the tenants themselves but, except where otherwise stated,
was under the personal supervision of the writer or an assistant.
As it was deemed advisable to apply the treatment to all fields
at the same time, the tenants and their families were organized
into one party which treated the fields successively.
The several crops were harvested by the tenants and all
weights verified by Plant Board employees.
CHECK FIELDS
In testing any method on a plantation scale the object is to
secure the most profitable crop possible over the entire acreage.
However, the amount of profit derived from the weevil control
operations cannot be definitely ascertained unless some fields
are left untreated for comparison.
In this experiment there were two check fields available. One
of these, known as check field No. 1, was just across the high-
way from the Smith plantation. Check field No. 2 was on the
opposite side of the plantation. Soils, surroundings and other
conditions with reference to these check fields were not notice-
ably different from those receiving the treatment.
Examination of all fields was made by Plant Board employees
on July 1, July 15, August 1 and August 15 to determine the
percentage of weevil infestation. The results of these examina-
tions are recorded in Table 7.
Check field No. 1 (containing 3.27 acres) produced 350 pounds
of seed cotton or 107 pounds to the acre. This was the same
field that was used as a check for comparison with the treated
fields on the Sanders place. Check field No. 2 (containing 2.26
acres) produced 449 pounds of seed cotton or 198 pounds to
the acre.
The total acreage of the two check fields was 5.53 and the total
production of the two was 799 pounds of seed cotton or an
average production of 144 pounds to the acre.
In discussing the several treated fields, comparisons of yield
are made, in some cases, between the treated and the check
field located nearest to it. Where the treated field was not in
close proximity to one of the checks, comparison is made with
the average of the two check fields.




































Fig. 7.-Full fruitage (bottom, middle and top crop) of cotton resulting from use of the improved method of weevil
control (field of John Robinson, col.)


"-~9r







Bulletin 165, Improved Method Boll Weevil Control 47

TREATED FIELDS
Field No. 1
John Robinson (col.), Tenant
This field of 14.93 acres was on land where the weevils had
destroyed practically the entire crop in 1921. About four out
of the 14.93 acres received a light application of barnyard manure
during the winter of 1921-22. A very poor stand, approximately
60 percent of normal, was secured on about two-thirds of the
field.
All squares were removed from the plants on May 28 but
heavy rains delayed application of poison until June 1. By this
time a few small squares had appeared and these doubtless per-
mitted some of the weevils to escape.
The cost of treating this field was:
Labor, picking off squares, 130 hours at $.06... .................... $7.80
Labor, applying poison, 30 hours at $.10.................... 3.00
Calcium arsenate, 89.5 lbs. at $.10.................. ................. 8.95
Total .......... ....... ----- ... ............... .... $19.75
Cost, an acre......................... ---- ..--- -..... ..... $ 1.32
The field of 14.93 acres produced 9,100 pounds of seed cotton
or 609 pounds to the acre.
The production is thus compared with that of the untreated
field:
Treated ........... ........ ........- -- ------------ 609 lbs. to the acre
Check .......... ........------------------........ 107 lbs. to the acre
Increase in production, treated field............502 lbs. to the acre
The value of this increase in production is estimated as fol-
lows:
167.3 lbs. lint at $.21.... ............... ..... ...... -...........$35.13
334.7 lbs. seed at $32 a ton ............... ..........- ............ 5.35
Total .... ..... -------- ---- ...-.. $40.48
Deducting the cost of treatment ($1.32) we find that the
profit from controlling the weevil was $39.16 to the acre. Figure
7 shows a view of this field.
Field No. 2
"Parson" Brown (col.), Tenant
This field contained 4.81 acres and was located about 100 yards
from where cotton had been grown in 1921. Corn fields were on
three sides and dense woodland on one side. Treatment for the
weevil was given by the tenant without supervision. The "par-
son" took his time in removing the squares and succeeded in







Florida Agricultural Experiment Station


completing the operation between May 29 and June 8 and on the
latter date he applied poison at the rate of five pounds to the
acre, the estimated cost of treatment being:
Labor, removing squares, 40 hours at $.06 ................. $2.40
Labor, applying poison, 6 hours at $.10 .... ................. .. .... GO
Calcium arsenate, 24.05 lbs. at $.10 .. ............... ..-..... 2.10
Total ----.......~......--- ---. ......... $5.40
Cost, an acre ..... ................... ...... ... $1.12
The field produced 2,268 pounds of seed cotton, or 471 pounds
to the acre, which makes possible the following comparison with
the average production of the two check fields:
Treated ................ ............. .........471 lbs. to the acre
Check fields --- ........ ................ 144 lbs. to the acre
Increase in production, treated field......... 327 lbs. to the a:re
This increase of 327 pounds is valued as follows:
109 lbs. lint at $.21 ....... .... ............ .. .... $22.89
218 lbs. seed at $32 a ton................ .. ................. 3.48
Total ..................................$26.37
From the value of the increase in production ($26.37) must
be deducted the cost of weevil treatment ($1.12) which shows
an acre profit of $25.25 from the control operations.

Field No. 3
Lewis Frazier (col.), Tenant
This field of 22.49 acres was separated from field No. 2 by only
a wire fence and was about 100 yards from where cotton was
grown last year. Good weevil hibernating quarters abounded in
all directions.
The squares were removed and poison applied June 4 and 5,
the poison being applied as rapidly as the square-picking crew
covered the field. The conditions under which the treatment was
given were all that could be desired but the tenant became crip-
pled on June 10 and the field was cultivated only once.
The cost of treatment was:
Labor, picking off squares, 160 hours at $.06.......................... $9.60
Labor, applying poison, 50 hours at $.10 ..........---- ----- 15.00
Calcium arsenate, 157.4 lbs. at $.10.-.. ......-....--- ----- 15.74
Total ..... .... .. ....... ------.... -$30.34
Cost, an acre....... -- .... ...................... -- --- 1.35
This field produced 7,632 pounds of seed cotton, or 339 pounds
to the acre, while the two check fields averaged 144 pounds to
the acre, thus affording this comparison:







Bulletin 165, Improved Method Boll Weevil Control 49

Treated .................. ...... ..... ................... 339 bs. to the acre
Check fields ............. ...................... .....144 bs. to the acre
Increase in production, treated field....................195 lbs. to the acre
This increase is valued as follows:
65 bs. lint at $.21..............----..............................$13.65
130 lbs. seed at $32 a ton...... ......... ...... ......................... 2.08
Total ........ .-- ... ..................$15.73
Deducting the cost of treatment ($1.35) we see that the acre
profit amounted to $14.38, despite the lack of cultivation.

Field No. 4
Newton Mayhew (col.), Tenant
Field No. 4, containing 5.64 acres, was located just across the
public highway from No. 3. The stand was very poor. An actual
count of the plants showed the stand to be only 41 percent of
normal.
On June 6 the squares were removed and poison applied. The
cost was:
Labor, picking off squares, 56 hours at $.06..................................$3.36
Labor, applying poison, 12 hours at $.10................................... 1.20
Calcium arsenate, 45 lbs. at $.10 ............................................... 4.50
Total ---.-- ----.. ..-- ........ ........ $9.06
Cost, an acre........ ... ......... ....... .... ..................$1.60
The production of field No. 4 was 2,290 pounds of seed cotton
or 406 pounds to the acre. This is compared with the production
of the check as follows:
Treated --.............. -. .. ......--.. 406 lbs. to the acre
Check fields .............. ........... ..-- -.. -144 lbs. to the acre
Increase in production, treated field..........262 lbs. to the acre
The value of this increase is estimated as follows:
87.3 lbs. lint at $.21........... .......................$18.33
174.0 lbs. seed at $32 a ton ...............-... .......... .. 2.79
Total ...... .............. ........ .... ..............- $21.12
After deducting $1.60, the cost of treatment, it is seen that
the weevil control operation gave a profit of $19.52 to the acre.

Field No. 5
Newton Mayhew (col.), Tenant
Ideal weevil hibernating quarters surrounded this field of 4.93
acres, and its soil appeared to be slightly better than the average
of the other fields on the plantation.







50 Florida Agricultural Experiment Station

On June 6 the squares were removed and poison applied. The
cost was as follows:
Labor, picking off squares, 40 hours at $.06 .................................$2.40
Labor, applying poison, 10 hours at $.10---..................... ------.. --.. ..... 1.00
Calcium arsenate, 25 lbs. at $.10 -.................. -... .. ..-..... 2.50
Total .......----... .....--- ----... ....----- ..... .. $5.90
Cost, an acre ........... .. .. ............................. ... ....-- $1.19
The field produced 2,409 pounds of seed cotton, or 488 pounds
to the acre. The stand was poor; an actual count of the plants
showed the stand to be only 49 percent of normal. The actual
yield is here compared with the average yield of the checks:
Treated ...... ..... ................ .. ........... 488 lbs. to the acre
Check fields .........-.......--.....--....---......144 lbs. to the acre
Increase in production, treated field:......-....344 lbs. to the acre
The value of this increase of 344 pounds is estimated as fol-
lows:
114.6 lbs. lint at $.21...............---- .....-- ......------$24.06
229.4 lbs. seed at $32 a ton --................ ........--- -...... 3.67
Total ...........-------....... ---------- --..................$27.73
Deducting from this the cost of treatment ($1.19), leaves
$26.54 to the acre as the profit resulting from weevil control.

Field No. 6
Bud Mayhew (col.), Tenant
Cotton had been grown during 1921 on a portion of this field
of 3.05 acres and the field started off in 1922 with an abundance
of weevils.
Squares were removed and poison applied June 7. A drizzling
rain occurred just as the application of poison was finished but
apparently the poison was not affected. The cost of treatment
was:
Labor, picking off squares, 32 hours at $.06............................... $1.92
Labor, applying poison, 8 hours at $.10-................... -............. .80
Calcium arsenate, 18.3 lbs. at $.10 ...............------................ 1.83
Total ......-........ ........--..----- ..------$4.55
Cost, an acre ................. --- --------.....$1.49
This field of 3.05 acres produced 1,385 pounds of seed cotton,
an average of 454 pounds to the acre. This yield is compared
with the average of the two checks, as follows:
Treated ....--..........-....-- .....-....-...----...---- 454 lbs. to the acre
Check fields -..............-...........-..... .....-- -- -..144 lbs. to the acre
Increase in production, treated field........ 310 lbs. to the acre







Bulletin 165, Improved Method Boll Weevil Control 51

The market value of the 310 pounds of seed cotton is arrived
at in the following manner:
103.3 lbs. lint at $.21 ............ ................... ... ... $21.69
206.7 lbs. seed at $32 a ton........................................ ....... 3.30
Total .... ................. ........ .. .... .. ...... ..... .... ..... $24.99
The value of the increase ($24.99), less the cost of treatment
($1.49), shows the profit to have been $23.50 to the acre.

Field No. 7
Bud Mayhew (col.), Tenant
Field No. 7, containing 11.57 acres, presented an unusual con-
dition from the standpoint of weevil infestation. Immediately
adjoining it was a field in which cotton grew last year and in
which volunteer or stubble plants grew this spring. Examina-
tion of this field early in June showed that a generation of
weevils had already developed and some of these had evidently
drifted into field No. 7.
It was quite evident that removal of the weevils from the
cultivated field would avail little if the weevil hatchery in the
stubble cotton were allowed to remain. Therefore, we destroyed
the stubble cotton and all fallen squares.
This field was one of the oldest, from point of cultivation, on
the place and the soil was decidedly impoverished. Added to this
handicap, the tenant gave the crop indifferent care and culti-
vation during the growing period.
On June 7 the squares were removed and one application of
poison made, at a cost detailed as follows:
Labor, picking off squares, 110 hours at $.06.....--- .. ........... $6.60
Labor, applying poison, 25 hours at $.10 ..-.. ............ 2.50
Calcium arsenate, 92.5 lbs. at 8.10- ..-..............-..... ...-......-- 9.25
Total ...- .. .. ................. .......... $18.35
Cost, an acre .....-..- ....--- .... -- ... -- -------.... ....$ 1.58
The field of 11.57 acres yielded 4,171 pounds of seed cotton,
an average of 360 pounds to the acre. Its yield is, therefore,
compared with the average yield of the two check fields in the
following manner:
Treated ---......... ........ ...... 360 lbs. to the acre
Check fields ... ---........- ............. 144 lbs. to the acre
Increase in production, treated field ............... 216 lbs. to the acre
Calculation of the value of this increase is made thus:
72 lbs. lint at $.21 ... ......... ................ .... $15.12
144 lbs. seed at $32 a ton.. ....... ................................ 2.30


Total .


------- ------------------_-------$ 1 7. 4 2









































Fig. 8.-Profitable crop of upland cotton secured by Arch Kelly as a result of applying the improved method of weevil
control (original)






Bulletin 165, Improved Method Boll Weevil Control 53

After subtracting from this figure the cost of treatment
($1.58), there remains $15.84 profit to the acre.

Field No. 8
Arch Kelly, Tenant
Mr. Kelly is a successful white farmer with many years of ex-
perience as a practical cotton grower. He was sufficiently inter-
ested in the efforts to find a satisfactory means of controlling the
boll weevil to undertake the treatment, as directed, on his main
field of 19.47 acres. This field was planted to Lewis 63 the last
week in March and fertilized with 50 pounds of kainit to the acre.
Mr. Kelly was, however, somewhat dubious about weevil control
measures and, for his own observation and comparison, planted
a nearby field (containing 2.26 acres), in which no effort was
made to control the weevil.
Mr. Kelly supervised the treatment, from June 1 to 5, of his
main field without assistance from Plant Board employees. He
did not keep an accurate record of the time and material required
but, from the size of his cotton at the time of treatment and the
cost incurred in other fields, it seems safe to estimate the acre
cost at $1.25.
The production in Mr. Kelly's treated field affords data for
an interesting and significant comparison between the profit to
be derived from controlling the weevil on good land, on the one
hand, and poor land, on the other. The best land, consisting of
10.46 acres, produced 5,601 pounds of seed cotton, or 535 pounds
to the acre. The remaining 9.01 acres, being poorer soil, pro-
duced a total of 3,067 pounds, or an average of only 340 pounds
to the acre. Yet the acre cost of controlling the weevil in these
two parts of the field was the same!
The non-treated field of 2.26 acres produced 449 pounds of
seed cotton, an average of 198 pounds to the acre.
These data permit the following comparison of yields between
the best and the poorest parts of the treated field and the check:
Increase due
to weevil con-
Treated field, Check field, trol, lbs. seed
lbs. seed cot- lbs. seed cot- cotton to the
ton to the acre ton to the acre acre
Good land .. ..-----....------ 535 198 337
Poor land .........------------340 198 142
Entire field ..................445 198 247
If the value of the increased production on the best land be
computed at the rate of $.21 a pound for lint and $32 a ton for






Florida Agricultural Experiment Station


the seed, it will be found to be $27.17. In like manner, the value
of the increase of 142 pounds to the acre on the poorer land will
be found to be $11.44. Deducting the cost of treatment ($1.25)
in each instance we have $25.92 and $10.19, respectively, as the
profit derived from the weevil-control operation on the good and
the poor land. Figure 8 shows the production secured by Mr.
Kelly on his best land.
It is admitted that the fertility of the soil in the check plot was
perhaps comparable with that of the poorer portion of the treat-
ed field, rather than with that of the portion which produced at
the rate of 535 pounds. However, this does not alter the signifi-
cance of the figures; the treatment for boll weevil made it pos-
sible for the better land to produce in proportion to its ability.
The better the land and the better the care the crop receives, the
greater the profit from controlling the weevil.
The comparison between the production of all Mr. Kelly's
treated and non-treated cotton is made in this way:
Treated ..-.......-- .... --....-.. -- ..-...-- .....-....445 bs. to the acre
Non-treated ......... -.... ---....-.... -.. ...-.. 198 lbs. to the acre
Increase in production, treated field..........-247 Ibs. to the acre
This average increase in production is valued as follows:
82.3 lbs. lint at $.21................................... .. .... .. $17.28
164.7 lbs. seed at $32 a ton.................-......... ..- ............ 2.63
Total --.............. --- ---------- .$19.91
Deducting the estimated cost of treatment for the weevil
($1.25), there remains $18.66 to the acre as the profit derived
by Mr. Kelly from the control operations on his entire field of
19.47 acres.

Field No. 9
Horace Williams (col.), Tenant
Horace Williams' field of 8.21 acres was almost entirely sur-
rounded by timber, which afforded unusually favorable hiber-
nating quarters for the weevil. About half the field consisted of
poor soil and the remainder of fairly productive soil. The culti-
vation given the crop was very indifferent.
On June 8 the squares were removed and calcium arsenate
applied. As the plants were small at this time and the stand
quite scattering only five pounds to the acre of poison were re-
quired. The cost of treatment was as follows:








Bulletin 165, Improved Method Boll Weevil Control 55

Labor, picking off squares, 70 hours at $.06........... ....... ......... $4.20
Labor, applying poison, 14 hours at $.10............................... 1.40
Calcium arsenate, 41 lbs. at $.10 .................... ........... .. 4.10
Total ......... ...................... ...... $9.70
Cost, an acre ........----. .. --- .... ...... ..... .... ................ 1.18

The treated field of 8.21 acres produced 3,207 pounds of seed
cotton, an average of 391 pounds to the acre, despite the poor
soil, poor stand and poor cultivation. This yield is thus compared
with the average yield of the two check fields:
Treated ................. ................. 391 lbs. to the acre
Check fields ........ ....... ....- ....144 lbs. to the acre
Increase in production, treated field..........247 lbs. to the acre

Estimating the value of this increase as in previous experi-
ments, we have:
82.3 lbs. lint at $.21 ..... ......................... ................... $17.28
164.7 lbs. seed at $32 a ton................... ............. 2.63
Total ........ ............. ................ 19.91
T t l ------------- ... ----- --0------------ ------------------------ $ 9 9
After subtracting the cost of weevil control ($1.18), there re-
mains $18.73 as the acre profit which resulted from the treat-
ment.
INFESTATION RECORDS, PLANTATION EXPERIMENT
Table 7 shows the degree of weevil infestation prevailing in
each of the treated and non-treated fields on the Smith planta-
tion from July 1 to August 15.

TABLE 7.-RECORDS OF INFESTATION, PLANTATION TEST
Fie.d Weevil Infestation, percent
July 1 July 15 F Aug. 1 Aug. 15
Check No. 1 .......--- 14.0 70.0 89.9 98.0
Check No. 2.............- 19.0 51.0 79.0 99.0
Treated, No. 1......- 0.0 11.0 54.9 i 88.0
Treated, No. 2........ 0.0 1.6 32.0 76.0
Treated, No. 3................ 0.2 5.7 34.0 79.0
Treated, No. 4 ........ 0.0 1.2 29.0 85.0
Treated, No. 5.......... 0.0 1.0 29.0 79.0
Treated, No. 6 ... .....! 0.0 1.7 50.3 79.0
Treated, No. 7 ....- 0.03 0.03 19.0 78.0
Treated, No. 8 ........ 0.0 4.6 43.0 84.0
Treated, No. -,---.. 0.0 0.0 34.0 1 79.0

The figures of Table 7 show that the average infestation upon
the several dates in the non-treated fields, on the one hand, and
in the treated fields, on the other, was:
July 1 July 15 Aug. 1 Aug. 15
Check fields .......16.5 60.5 84.4 98.5
Treated fields ........0.03 3.0 36.1 81.0








Florida Agricultural Experiment Station


The significance of the record in Table 7 is that the treated
fields remained, for all practical purposes, free from weevils from
the time of treatment early in June until after the middle of July.
This was a period of over six weeks during which the plants
could set bolls without interference from the weevil. Even when
the square infestation reached 36.1 percent on August 1, prac-
tically no attack was being made upon the young bolls, as the
weevils still had plenty of squares in which to work. As is well
known, the setting of bolls does not cease entirely until the per-
centage of square infestation reaches approximately 100.
The difference in infestation, as the season progressed, be-
tween the treated and check fields was fully in keeping with
the difference in cotton produced.

Table 8 summarizes the cost of controlling the boll weevil, by
the methods heretofore described, in the nine treated fields on
the Smith plantation.

TABLE 8.-CosT OF BOLL WEEVIL CONTROL, SMITH PLANTATION


Field Acres




1 14.93
2 4.81
3 22.49
4 5.64
5 4.93
6 3.05
7 11.57
8 19.47
9 8.21
Totals | 95.10
Averages ............


L


Picking
squar




0

$7.80
2.40
9.60
3.36
2.40
1.92
6.60
9.73
4.20
|$48.01 ..
....:...........


abor


off Apply ing
es poison




0 o C)

$.52 $3.00 $.20
.50 .60 .12
.43 5.00 .22
.59 1.20 .21
.49 1.00 .20
.63 .80 .26
.57 2.50 .21
.50 3.89 .20
.51 1.40 .17
......... 1$19.39 i..........
.53 ............ $.20


-4-
Poison
03
Ho






89.5 6 $.60 1 $1.32
24.05 5 .50 1.12
157.4 7 .70 1.35
45.0 8 .80 1.60
25.0 5 .50 1.19
18.3 6 .60 1.49
92.5 8 .80 1.58
107.0 5/2 .55 1.25
41.0 5 .50 1.18
599.7 ......... ..... I .....
............--I 6.2 1 $.62 $1.34


Table 9 summarizes the increase in cotton production in the
Smith fields in which this method of weevil control was applied,
the cost of such treatment, the value of the increase in crop at
the current prices of $.21 a pound for lint and $32 a ton for seed,
and the profit derived from the operation.







Bulletin 165, Improved Method Boll Weevil Control 57

TABLE 9.-PRODUCTION AND PROFITS, TREATED COTTON FIELDS,
SMITH PLANTATION








1 609 107 502 $40.48 $1.32 $39.16
C -



2 471 144 327 26.37 1.12 25.55



3 339 144 195 15.73 1.35 14.38
4 406 144 262 21.12 1.60 19.52
5 488 144 344 27.73 1.19 26.54
6 454 144 310 24.99 1.49 23.50
7 360 144 216 17.42 1.58 15.84
8 445 198 247 19.91 1.25 18.66
Aver- |
ages 440* ...................._ 294 $23.74 $1.34 $22.43
*By dividing the total production of all 9 fields (41,126 pounds) by the
total acreage (95.1) an average of "432 is secured.

From the foregoing table it is seen that the cost of treatment

varied from $1.12 to $1.60 an acre. This variation was caused






by the difference in size of plants and varying stand in the dif-
ferent fields.
By far the most significant fact of the above results is that
Mr. Smith apparently increased the cotton crop on 95.1 acres
to the extent of $2257.67". If we deduct from this the cost of
controlling the boll weevil on the 95.1 acres, which was $127.37",caused
we see that by using this method of weevil control he made a
net profit of $2130.30.


RESULTS OF APPLYING CONTROL MEASURES TOO EARLY
While it is very evident that the dual treatment of square-
stripping and poisoning cannot givthethe best results when used
prior to the time when practically all weevils are outhis the cost of hiberna-

tion, nevertheless it was deemed desirable to inaugurate experi-
ments to ascertain the actual effect of early treatments.
For this purpose four fields were available on the plantation
of C. E. Davis, two miles southwest of Madison. The land was
well drained and consisted of Orangeburg sandy loam. Cotton

his figure is arrived at by multiplying the average acre increase in





value ($23.74) by the total treated acreage (95.1).
"Actual total cost, see Table 8.






Florida Agricultural Experiment Station


had been grown on the plantation the previous year. Excellent
hibernating quarters for the boll weevil surrounded the fields.
All fields were planted to mixed seed of upland cotton about
March 12. No fertilizer was used. Planting and cultivating were
done by negro tenants. The writer supervised the treatments,
and Plant Board employees supervised the picking and weighing
of the cotton.
One of the four fields was left untreated for a check, while the
other three received the weevil control treatment several days
earlier than in the experiments already described.
CHECK FIELD
A good stand was secured in the check field of 5.71 acres and
it yielded 1,370 pounds of seed cotton, or 239 pounds to the acre.
The percentage of weevil infestation in the check and in the
three treated fields, as determined by examinations on July 1,
July 15, August 1 and August 15, is shown in Table 10.

TABLE 10.-RECORD OF INFESTATION, DAVIS PLANTATION
Field July I July 15 Aug. 1 Aug. 15
Check .. .................... 0.0 [ 61.0 76.0 100.0
Treated Fields:
No. 1 ...............- ........... 0.01 13.0 80.0 88.0
No. 2 ................................ 0.5 20.0 69.0 86.0
N o. 3 ..................... ......... 0.05 38.0 76.0 88.0

TREATED FIELDS
Field No. 1
Pomp Johnson (col.), Tenant
A part of this field of 4.52 acres was in cotton last year and a
heavy weevil infestation was present this spring. Not over 80
percent of a stand was secured.
On May 18 all squares were removed and calcium arsenate ap-
plied at the rate of five pounds to the acre, the cost of treatment
being as follows:
Labor, picking off squares, 55 hours at $.06.................................$3.30
Labor, applying poison, 8 hours at $.10 ..........-....... ....-.....-- .80
Calcium arsenate, 22.6 lbs., at $.10......... ................... ... 2.26
Total .. ..... ........................... ... $6.36
Cost, an acre .................... .-. ....-- ...... $1.41
Between June 1 and 5 a light infestation was found in this
field due, apparently, to hibernated weevils. It was quite evi-
dent that the treatment had been given too early.
The treated field produced 2,545 pounds of seed cotton, or 563







Bulletin 165, Improved Method Boll Weevil Control 59

pounds to the acre. This permits the following comparison with
the check field:
Treated -..................... .......... 563 lbs. to the acre
Check ................ ............. .. .............. 239 lbs. to the acre
Increase in production, treated field............324 lbs. to the acre
The value of this increase of 324 pounds is found as follows:
108 lbs. lint at $.21 --.....-.---- -.... .......... $22.68
216 lbs. seed at $32 a ton.... ................- ............. 3.45
Total ..... ..... ..- ..- ..........................$26.13
If the cost of treatment ($1.40) be deducted from the value of
the increase, there will remain an apparent profit of $24.73 to
the acre. A study of the infestation records indicates that a
greater average profit could have been secured had the treat-
ment been deferred for a few days.

Field No. 2
Pomp Johnson (col.), Tenant
This field of 3.67 acres was located about 100 yards from the
field described above. Squares were removed on May 18 and
calcium arsenate applied the same day at a cost of:


Labor, picking off squares, 20 hours at $.06.
Labor, applying poison, 7 hours at $.10.......
Calcium arsenate, 18.35 lbs. at $.10..........-...
Total ...... -- ----
Cost, an acre ...........................


-...............-.......-......$1.20
...... ..... ....... .70
.-- ..-- .......-. 1.83
...........................$3.73
...............$1.01


As in the former experiment, a light infestation by over-win-
tered weevils was found in the field a few days after treatment.
The stand in this field was very poor. By actual count the
number of cotton plants on the 3.67 acres was no more than suf-
ficient to cover 1.79 acres with a perfect stand. Any comparison
of the yields of this field and the check, on the basis of acre pro-
duction, could not, therefore, show the increase in the crop ac-
tually secured by the weevil control operations. However, the
comparison of actual yields is:


Treated _
Check .....


....321 lbs. to the acre
....239 lbs. to the acre


Increase in production, treated field......... 82 lbs. to the acre
This increase of 82 pounds to the acre, valued at $.21 a pound
for lint and $32 a ton for seed, is worth $6.60. After deducting
the cost of treatment ($1.01), there remains an apparent profit
of $5.59 to the acre.






Florida Agricultural Experiment Station


Field-No. 3
Rich Cambric (col.), Tenant
Field No. 3 contained 6.18 acres. The land was decidedly poorer
than that in the check field and during the season damage by
cotton wilt was very severe.
Treatment to dispose of weevils was applied on May 19 at a
cost of:
Labor, picking off squares, 40 hours at $.06................................$2.40
Labor, applying poison, 10 hours at $.10.................................... ----- 1.00
Calcium arsenate, 30.9 lbs. at $.10 -....................... ........ .. 3.09
Total ............ ...........- ....- ... .. ---..........$6.49
Cost, an acre .......- ..... ............. ........ $1.08

The weevil infestation in this field appeared early and in-
creased rapidly.
By actual count it was found that there were only 22,190
plants in this field of 6.18 acres, or the number required for a
perfect stand on 3.05 acres. As in the case of field No. 2, a
comparison of yield with that of the check cannot show the real
increase in production due to weevil control. Field No. 3 pro-
duced 1,470 pounds of seed cotton, or 245 pounds to the acre.
This yield would be compared with that of the check in this
way:
Treated .. ....~. ................ 245 lbs. to the acre
Check ....-..- .. -----...-..... 238 lbs. to the acre
Increase in production, treated field............ 7 lbs. to the acre

The value of this difference in production, 7 pounds, if cal-
culated as heretofore, would be $.55. As the cost of treating this
field was $1.05 an acre, a "loss" of $.50 to the acre is indicated.
Comparison of the July infestation in these fields and in those
which received the weevil control treatment a few days later,
shows that hibernated weevils entered these fields after the
treatment in sufficient numbers to cause a pronounced infestation
of the crop from the start. These treatments, tho too early, did
considerable good, for the yield in the treated fields was appre-
ciably larger than it otherwise would have been.
At the same time, the lesson is clear, from this field test, that
satisfactory results from this method of weevil control cannot
be secured if it is applied before practically all weevils are out of
hibernation.








Bulletin 165, Improved Method Boll Weevil Control 61


SUMMARY, ALL FIELD EXPERIMENTS, UPLAND COTTON

In Table 11 will be found a summary of the production in all
of the fields of upland cotton in which the improved method of
control was used. This table includes all fields in which the treat-
ment was supervised by Plant Board employees as well as all
those treated by the owners. Of the 20 fields, 18 were in Madison,
1 in Suwanee and 1 in Alachua County.

TABLE 11.-PRODUCTION OF ALL TREATED FIELDS


Treated field


Sanders, No. 1..........
Sanders, No. 2..........
Sanders, No. 3.........
Sanders, No. 4.........
Sanders, No. 5.......
H odge .......................
Wimberly ...........-..
Gainesville ............
Smith Plantation:
No. 1 .......... ....
N o. 2 ............. .. ..
N o. 3 ....................-.
N o. 4 ........................
No. 5 ..............--..-
N o. 6 ............... .
N o. 7 ............... .. ...
No. 8 .............-.----
N o. 9 ........... ..... ...
Davis:
No. 1 ...................--
No. 2 ......----.. ----
No. 3 .............-.-....
Average .......


o o







................ I 356 $28.70
................ 524 42.26
---........ -... 228 18.39
......... 379 30.56
516 41.62


.......... 523 42.18
S- 6........ 11 49.27
............... 550 44.36

... ...... 609 49.13
----..... 471 37.99
-- -.-.-- 339 27.35
------ 406 32.74
488 39.35
--. -..... 454 36.62
--- ----..--- 360 29.04
... ...-.... 445 35.89
---- -......... 391 31.53

...... -... 563 45.41
321 25.89
--------245** 19.75
--.--.------ -- 439*** | $35.42


*Cotton plants too far advanced at time
the abnormally high cost.


SC






$1.11
1.30
1.28
1.31
1.72
1.01
1.50
6.64*

1.32
1.12
1.35
1.60
1.19
1.49
1.58
1.25
1.18

1.41
1.01
1.08
$1.57***


of treatment, which explains


**Crop severely damaged by wilt, or "black root."
***Total production, all treated fields, divided by their total acreage, gives
432 pounds to the acre.
****The cost of treatment in the case of the Gainesville field really should
not be included in arriving at this average. Leaving the Gainesville
field out of account, the cost of treatment in the other 19 fields averaged
$1.31 to the acre.

The production of all the non-treated fields used as checks is
shown in Table 12.






Florida Agricultural Experiment Station


TABLE 12.-PRODUCTION OF ALL CHECK FIELDS

Pounds seed Acre value of crop, at $.21
to the acre a pound for lint and $32 a
ton for seed
Sanders .................. 107 $8.62
Hodge ................. 111 8.95
Plantation
N o. 1................. 107* ..
No. 2 ...............- 198 15.97
Davis ....-.............- 239 1 9.27
Average ............. 164 $13.20
*Same field as Sanders check. Included only once in arriving at average
production.
Tables 11 and 12 show that the average crop of short staple
cotton in all treated fields was worth $35.42 to the acre, while
the average crop of the untreated fields was worth $13.20 to the
acre, a difference of $22.22. This difference was brought about
solely by controlling the weevil at an average acre cost (in 20
fields) of $1.57.
The fact that this substantial increase in production was se-
cured in all fields-regardless of lack of fertilizer, destruction
by wilt, poor cultivation, storm damage, etc.-indicates that the
method, properly applied, is dependable.
All other things being equal, the size of the crop depends
upon the quality of the land, the variety of cotton, the fertilizer
used and the care given. Lacking these things, a large yield can-
not be secured, no matter how completely the weevil is con-
trolled. The treatment here described cannot produce cotton;
it can only protect it.
The 20 treated fields averaged 439 pounds of seed cotton, while
the untreated check fields averaged 164 pounds, an increase of
275 pounds to the acre.
The Florida cotton acreage of 1922 is estimated by statisti-
cians of the United States Department of Agriculture at 122,000
acres. Had the improved method of weevil control been applied
to this acreage with results as good as those obtained in our
20 experimental fields, Florida's cotton crop this year would have
been increased by 33,550,000 pounds (seed cotton), or 22,366
bales, as well as 11,183 tons of seed.
POISONING EXPERIMENTS IN CAGES
To determine what effect, if any, removal of the squares from
the plants would have on increasing the effectiveness of one ap-
plication of poison, a number of experiments were made from






Bulletin 165, Improved Method Boll Weevil Control 63

June to September, inclusive. In these experiments the poison
was applied to cotton plants inside of cages. The cages were
4x4x41/2 feet in dimensions and were made of 16-mesh gal-
vanized wire cloth securely tacked to a substantial wooden
framework.


Fig. 9.-Chart showing weevil mortality under certain conditions: (a) all
squares removed, followed by application of poison (heavy line); (b) pois-
oning without removal of squares (dotted line); (c) without either squares
removed or poisoning (broken line)

Active adult boll weevils, collected from a nearby cotton field,
were placed in the cages on (1) cotton plants from which the
squares had been removed and to which an application of cal-
cium arsenate had been made at the rate of about five pounds
to the acre, (2) cotton plants from which the squares had not
been removed, but to which the poison had been applied at the







64 Florida Agricultural Experiment Station

same rate, and (3) cotton plants with squares on them, to which
no poison had been applied. Examinations were made daily there-
after, when the dead weevils were removed and counted.
A large number of such tests were made, each involving from
ten to twenty-five weevils. Table 13 gives their results.

TABLE 13.-DAILY MORTALITY OF BOLL WEEVILS ON (1) POISONED COTTON
PLANTS FROM WHICH ALL SQUARES HAD BEEN REMOVED, (2) POISONED
COTTON PLANTS HAVING SQUARES ON THEM AND (3) NON-
POISONED COTTON PLANTS HAVING SQUARES UPON THEM

Poisoned Cotton
CHECK
228 Weevils 500 Weevils (Not poisoned or
S All squares Squares not stripped).
S0 removed. removed. Daily mortality,
o Daily mortality, Daily mortality, percent
Percent percent

1st .......... 82.01 14.0 1.0
2nd .......... 14.00 16.2 1.5
3rd .......... 3.5 10.8 1.6
4th .--.- .-- 9.0 1.5
5th ... .... .. 4.0 1.2
6th -... ..- 4.0 2.0
7th ......... ....... 5.0 .6
8th ....... ...... 5.3 1.2
9th -... 3.2 3.0
10th ....... 2.7 3.6
Totals ...- 99.59 74.2 17.2


From Table 13 it will be noted that when the poison was ap-
plied to cotton plants that had been stripped of their squares,
991/2 percent of the boll weevils were killed within three days.
On the other hand, when the poison was applied to plants which
had squares on them only 41 percent of the weevils were killed
within the first three days and, even at the end of ten days, only
74 percent had been killed. The third column shows the much
slower rate at which weevils died when they had no poison at all
to contend with.
The fact that practically all weevils were killed by the poison
within three days, when all squares had been removed, fully
explains why, in the field experiments already described, almost
total annihilation of the weevils followed a thoro application of







Bulletin 165, Improved Method Boll Weevil Control 65

poison just after the squares were stripped from the plants. The
data given in the above table are graphically shown in figure 9.

HOW TO USE THE IMPROVED METHOD OF CONTROL

The gist of the method may be summarized in two sentences,
as follows:
1. Remove all squares from the cotton plants about June 5
and destroy them.
2. Follow this at once with a thoro application of calcium
arsenate or lead arsenate, using a suitable dusting ma-
chine.
Simple as this procedure really is, there are many errors which
the farmer may make, and if he makes them, he will not satis-
factorily control the boll weevil. Therefore, it is necessary that
he study the results of the foregoing experiments and thoroly
master the points brought out in the following paragraphs.

THE PRINCIPLES INVOLVED
It is useless to attempt to control the weevils by this method
until practically all of them are out of their winter quarters. In
Florida this is normally about June 5. Treatment earlier than
this date will be followed by reinfestation of the fields.
The maximum effect of applying the poison cannot be secured
unless the cotton plants are first stripped of ALL squares.

REMOVAL OF SQUARES
It has been found that women and children are just as efficient
in gathering the squares as are men. Each worker should be
equipped with a tight, well-made cloth sack provided with a
draw-string for keeping the mouth closed (see figures 10 and
11). As the squares and weevils are picked from the plants they
are placed in the sack and taken from the field and burned, care
being taken to see that not a single weevil escapes.
Regardless of whether adults or children are employed, the
work should be closely supervised by a thoroly responsible and
observant person. It is of the utmost importance that EVERY
square be destroyed at this time. With large groups of negroes
it has been found advantageous to have individual families work
together, the head of the family keeping a close watch over the
work of his children as well as working himself. This plan of





W7


~'U>.


Fig. 10.-Illustrating type of


.r .

sack used for holding squares as they are removed from the plants. Note draw-strings
to keep sacks closed to prevent escape of weevils (original)


Wit I, -' ^-7






Bulletin 165, Improved Method Boll Weevil Control


grouping the col-
ored people, chil-
dren particularly,
helps to eliminate
conversation and
careless work.
The square-
pickers should
commence at one
side of the field
and take plants
and rows as they
are reached. As
soon as possible
after the squares
are removed the
application o f
poison should be
made. Both op-
erations can be
carried on suc-
cessfully at one
time, as shown in
figure 12.


uK.-


Fig. 11.-Sacks, such as the fertilizer bag shown
at the left, are not suitable for collecting squares.
For this purpose use bags like that at the right,
which is made of strong cloth and closed with a
draw-string (original)


POISONS TO USE
There are only two poisons suitable for this work. One is
powdered arsenate of lead, the other calcium arsenate. They
are about equal in efficiency, so far as killing the weevil is con-
cerned. However, calcium arsenate, as manufactured at pres-
ent, seems to be in better physical condition for dusting than
most of the lead arsenate on the market, and it has the addi-
tional advantage of being slightly lower in price, pound for
pound. Due to abnormal trade conditions calcium arsenate has,
during the season of 1922, been available to the farmer at prices
varying from eight to thirteen cents a pound. It is likely, how-
ever, that prices during the coming season will be somewhat
higher.
Such poisons as paris green and london purple cannot be used.
They contain a relatively high content of water-soluble arsenic
and will severely injure the cotton plants. Various proprietary






Florida Agricultural Experiment Station


mixtures advertised as "boll weevil poisons" are practically
worthless.
Mixing the calcium or lead arsenate with molasses, flour, meal
or other material merely decreases its killing power. The farmer
will save money and get best results by using nothing except
calcium arsenate or powdered lead arsenate manufactured by
well-known firms.
It must be remembered that both calcium arsenate and lead
arsenate are powerful poisons and must be handled with care.
One should use the same precautions as in using paris green.
Care should be taken that children do not have access to the
poison. For the first ten days or two weeks after the poison is
applied work animals used in the cotton fields should be muzzled.
After handling or applying the poison, the operator should
thoroly wash his face and hands, using plenty of soap.

DUSTING MACHINERY

Success does not follow the application of the poison by sifting
it from cloth sacks. Neither will any type of duster give satis-
factory results unless it delivers the poison in a steady stream
and with considerable force. This can be accomplished only by
the type of duster which contains a rotary fan and a device
for accurately regulating the rate at which the poison is put
out. Unfortunately, most of the hand dusters on the market at
present are poorly constructed and will last for only a few days
without repair. The Leggett No. 2 duster, made by Leggett &'
Bro., New York, in spite of its many defects, is the best machine
we have found for this purpose.
One duster should be provided for each 10 acres of cotton.
However, as the dusters are likely to get out of order, the farmer
should provide himself with extra ones (the number depending
on his cotton acreage), in order that the poisoning operation may
be completed quickly and at the proper time.
Power dusting machinery is not suited to this work and its
purchase by the cotton farmer would be a waste of money. In
making the one application required by this method of weevil
control, it is necessary for the operator to give every cotton
plant his personal and careful attention. Every plant must have
the poison forced into its terminal bud. No dusting machine
has been made which will take the place of intelligence. The
best power dusters will miss many plants, particularly where



















'-.



0,




0s




,0













Fig.12.Remvin th eary suars ad fllowng mmeiatly ith he oisn (rignal






Florida Agricultural Experiment Station


the rows are not exactly the same distance apart, where the land
is uneven, or where there are stumps.
The object is not to scatter poison over the field at random,
but to force it actually into the terminal bud of every plant. The
poison will not kill the weevil by coming in contact with it.
With the type of hand dusting machine described herein, one
laborer can thoroly apply the poison to four or five acres a day.
CARING FOR THE POISON
The supply of poison should be kept always in a dry place and,
as far as possible, in air-tight containers.
For taking the poison to the fields ordinary tin lard cans have
been found satisfactory (see figure 13). They are not only
convenient to handle but protect the poison from rain.
The poison may
absorb too much
moisture, before
S. us reaching the
:. "farmer, unless it
is put up in prop-
er containers. We
strongly urge
farmers to pur-
chase only such
poison as is
shipped and sold
in tight contain-
ers, lined with
Fig. 13.-Tight tin cans, such as shown here, are waxed or paraf-
excellent for carrying poison to the field and pro- fin paper.
testing it from moisture (original)
APPLYING THE POISON
The farmer should thoroly study the construction of his dust-
ing machines and understand their operation before taking them
to the field.
The machine should be set to distribute from five to seven
pounds of poison to the acre. The rate can be tested by using,
say, a pound of poison on a measured length of row. However,
experience soon teaches the operator to tell by the volume of the
dust stream about how much he is putting out.
In applying the poison it is of the utmost importance that
the operator walk slowly and take pains to force the poison into
the small bunch of tender leaves at the tip of the plant.






Bulletin 165, Improved Method Boll Weevil Control 7i

When rank cotton is reached, as in a low or extra fertile spot,
the gauge should be opened slightly so as to deliver more poison,
or the operator should work more slh wly, so that all plants will
be thoroly treated.
As far as possible, applications of poison should be made when
there is little or no wind. Early morning and late afternoon are
usually the best periods, tho poisoning may be carried on all day
if there is little or no breeze. It is often practical to have all
hands devote their time to picking squares until mid-afternoon
and then apply poison until dark. If the stripped area is not
covered by night the poisoning can be continued the following
morning.
Applying the poison to plants when they are wet with dew
is advantageous, in that the moisture causes the poison to ad-
here well. Except for this, the presence of dew, or its absence,
has nothing whatever to do with the poisoning of the weevil".
The insect is poisoned only by eating the tender foliage and
buds to which the poison has been applied.
We do not advise applying the poison at night. There is no
necessity for it and, besides, the work cannot be done well in
the dark.

EFFECT OF RAINS ON THE POISON

In the Florida cotton belt there is always more or less chance
of showers early in June. A very light shower, coming after the
poison is applied, especially if it falls gently or slowly, is in most
cases an advantage in that it serves to stick the poison to the
plants.
However, a hard or long-continued rain will wash off the
poison. Table 13 shows that, when all squares have been removed
from the plants, practically all weevils are killed within three
days after the poison is applied. Therefore, if no rain falls for
two or three days after the poison is applied, a second applica-
tion is not necessary. By examination of the plants after a
shower one is able to determine whether the application needs to
be repeated. As long as plenty of poison remains in the terminal
buds, do not worry about the results

1Newell and Bynum: "Notes on Poisoning the Boll Weevil," Journal
of Economic Entomology, Vol. 13, pp. 123-125, Feb., 1920.






Florida Agricultural Experiment Station


AMOUNT OF POISON TO PURCHASE
On account of the possible necessity for repoisoning part of
the crop, due to rain, it is well for the cotton grower to secure
a supply of poison in excess of what is needed for the one ap-
plication. We suggest the purchase of about ten pounds of the
poison for each acre of cotton. Any that is not used can be
kept in good condition until the following season, if stored in
tight containers and kept in a dry place.

PROFITS PROPORTIONATE TO CARE OF CROP
It has been clearly pointed out that the largest profit from con-
trolling the boll weevil is invariably secured upon land capable
of making a relatively good crop. For the same reason cotton
fields which are planted to selected, wilt-resistant varieties, fer-
tilized and cultivated well, yield the largest returns as a result
of controlling the boll weevil by this method.
It is far better to plant a small acreage, use plenty of fer-
tilizer and give the best of care, than to plant a large acreage and
neglect these essentials.




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