• TABLE OF CONTENTS
HIDE
 Title Page
 Credits
 Table of Contents
 Fig. 2
 Introduction
 Field counts
 Hibernation cage experiments and...
 Hibernation cage experiments and...
 Hibernation cage experiments and...
 Hibernation cage experiments and...
 Summary of hibernation cage experiments...
 Comparison of emergence from hibernation...
 Summary and conclusions
 Literature cited














Group Title: Bulletin - University of Florida. Agricultural Experiment Station ; no. 233
Title: Determination of the winter survival of the cotton boll weevil by field counts
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027322/00001
 Material Information
Title: Determination of the winter survival of the cotton boll weevil by field counts
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 47 p. : ill., charts ; 23 cm.
Language: English
Creator: Grossman, Edgar F
Calhoun, P. W
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1931
 Subjects
Subject: Boll weevil -- Counting -- Florida   ( lcsh )
Boll weevil -- Wintering -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 47.
Statement of Responsibility: by Edgar F. Grossman and P.W. Calhoun.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station)
 Record Information
Bibliographic ID: UF00027322
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000924083
oclc - 18204110
notis - AEN4687

Table of Contents
    Title Page
        Page 1
    Credits
        Page 2
    Table of Contents
        Page 3
    Fig. 2
        Page 4
    Introduction
        Page 5
    Field counts
        Page 6
        Page 7
        Page 8
    Hibernation cage experiments and field counts, 1926-27
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
    Hibernation cage experiments and field counts, 1927-28
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
    Hibernation cage experiments and field counts, 1928-29
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
        Page 29
        Page 30
    Hibernation cage experiments and field counts, 1929-30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
    Summary of hibernation cage experiments and field counts, 1926-30
        Page 38
        Page 39
        Page 40
    Comparison of emergence from hibernation cages with field counts
        Page 41
        Page 42
        Page 43
        Page 44
    Summary and conclusions
        Page 45
        Page 46
    Literature cited
        Page 47
Full Text



Bulletin 233


June, 1931


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
Wilmon Newell, Director




DETERMINATION OF THE

WINTER SURVIVAL

OF THE COTTON BOLL WEEVIL

BY FIELD COUNTS

By
EDGAR F. GROSSMAN AND P. W. CALHOUN

53
-'30






15
L-27







.-
Zt1 ----CA GEit CMCRGEMCt FIELD EMtRGENCt--m-
V9


01a

6 1S 20 27 3 10 17 14 I 8 15 2Z 29 5 12 19 26 3
MARCH APRIL MAY JUNE JULY
Fig. 1.-Chart showing the weekly percentage of boll weevils emerging
from hibernation in cages, compared with the percentage appearing
in the field-four-year period, 1926-1930. (Cf. Table XXV.)


TECHNICAL BULLETIN


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









BOARD OF CONTROL

P. K. YONGE, Chairman, Pensacola RAYMER F. MAGUIRE, Orlando
A. H. BLENDING, Bartow FRANK J. WIDEMAN, West Palm Beach
W. B. DAVIS, Perry J. T. DIAMOND, Secretary, Tallahassee

STATION EXECUTIVE STAFF
JOHN J. TIGERT, M.A., LL.D., President 1.. M. FULGHUM, B.S.A., Asst. Editor
WILMON NEWELL, D.Sc., Director IDA KEELING CRESAP, Librarian
H. HAROLD HUME, M.S., Asst. Dir., Re- RUBY NEWHALL, Secretary
search K. H. GRAHAM, Business Manager
S. T. FLEMING, A.B., Asst. Dir., Admin. RACHEL McQUARRIE, Accountant
J. FRANCIS COOPER, M.S.A., Editor

MAIN STATION-DEPARTMENTS AND INVESTIGATORS


AGRONOMY
W. E. STOKES, M.S., Agronomist
W. A. LEUKEL, Ph.D., Associate
G. E. RITCHEY, M.S.A., Assistant*
FRED H. HULL, M.S., Assistant
J. D. WARNER, M.S., Assistant
JOHN P. CAMP, M.S.A., Assistant
ANIMAL HUSBANDRY
A. L. SHEALY, D.V.M., Veterinarian in
Charge
E. F. THOMAS, D.V.M., Asst. Veterinarian
R. B. BECKER, Ph.D., Associate in Dairy
Husbandry.
W. M. NEAL, Ph.D., Assistant in Animal
Nutrition
C. R. DAWSON, B.S.A., Assistant Dairy
Investigations
CHEMISTRY
R. W. RUPRECHT, Ph.D., Chemist
R. M. BARNETTE, Ph.D., Associate
C. E. BELL, M.S., Assistant
J. M. COLEMAN, B.S., Assistant
H. W. WINSOR, B.S.A., Assistant
H. W. JONES, B.S., Assistant
COTTON INVESTIGATIONS
E. F. GROSSMAN, M.A., Assistant
P. W. CALHOUN, B.S., Assistant


ECONOMICS, AGRICULTURAL
C. V. NOBLE, Ph.D., Agricultural Economist
BRUCE McKINLEY, A.B., B.S.A., Associate
M. A. BROOKER, Ph.D., Assistant
ECONOMICS, HOME
OUIDA DAVIS ABBOTT, Ph.D., Head
L. W. GADDUM, Ph.D., Biochemist
C. F. AHMANN, Ph.D., Physiologist
ENTOMOLOGY
J. R. WATSON, A. M., Entomologist
A. N. TISSOT, M.S., Assistant
H. E. BRATLEY, M.S.A., Assistant
L. W. ZIEGLER, B.S., Assistant
HORTICULTURE
A. F. CAMP, Ph.D., Horticulturist
HAROLD MOWRY, B.S.A., Associate
M. R. ENSIGN, M.S., Assistant
A. L. STAHL, Ph.D., Assistant
G. H. BLACKMON, M.S.A., Pecan Culturist
C. B. VAN CLEEF, M.S.A., Greenhouse
Foreman
PLANT PATHOLOGY
W. B. TISDALE, Ph.D., Plant Pathologist
G. F. WEBER, Ph.D., Associate
A. H. EDDINS, Ph.D., Assistant
K. W. LOUCKS, M.S., Assistant
ERDMAN WEST, M.S., Mycologist


BRANCH STATION AND FIELD WORKERS
L. O. GRATZ, Ph.D., Asso. Plant Pathologist in charge, Tobacco Exp. Sta. (Quincy)
R. R. KINCAID, M.S., Assistant Plant Pathologist (Quincy)
W. A. CARVER, Ph.D., Assistant, Cotton Investigations (Quincy)
RAYMOND M. CROWN, B.S.A., Field Asst., Cotton Investigations (Quincy)
JESSE REEVES, Farm Superintendent, Tobacco Experiment Station (Quincy)
J. H. JEFFERIES, Superintendent, Citrus Experiment Station (Lake Alfred)
GEO. D. RUEHLE, Ph.D., Assistant Plant Pathologist (Lake Alfred)
W. A. KUNTZ, A.M., Assistant Plant Pathologist (Lake Alfred)
B. R. FUDGE, Ph.D., Assistant Chemist (Lake Alfred)
W. L. THOMPSON, B.S., Assistant Entomologist (Lake Alfred)
R. V. ALLISON, Ph.D., Soils Specialist in charge Everglades Experiment Sta. (Belle Glade)
R. W. KIDDER, B.S., Foreman, Everglades Experiment Station (Belle Glade)
R. N. LOBDELL, M.S., Assistant Entomologist (Belle Glade)
F. D. STEVENS, B.S., Sugarcane Agronomist (Belle Glade)
H. H. WEDGEWORTH, M.S., Associate Plant Pathologist (Belle Glade)
B. A. BOURNE, M.S., Associate Plant Physiologist (Belle Glade)
J. R. NELLER, Ph.D., Associate Biochemist (Belle Glade)
A. DAANE, Ph.D., Associate Agronomist (Belle Glade)
FRED YOUNT, Office Assistant (Belle Glade)
M. R. BEDSOLE, M.S.A., Assistant Chemist (Belle Glade)
A. N. BROOKS, Ph.D., Associate Plant Pathologist (Plant City)
R. E. NOLEN, M.S.A., Field Assistant in Plant Pathology (Plant City)
A. S. RHOADS, Ph.D., Associate Plant Pathologist (Cocoa)
C. M. TUCKER, Ph.D., Associate Plant Pathologist (Hastings)
H. S. WOLFE, Ph.D., Associate Horticulturist (Homestead)
L. R. TOY, B.S.A., Assistant Horticulturist (Homestead)
STACY O. HAWKINS, M.A., Field Assistant in Plant Pathology (Homestead)
D. G. A. KELBERT, Field Assistant in Plant Pathology (Bradenton)
FRED W. WALKER, Assistant Entomologist (Monticello)
D. A. SANDERS, D.V.M., Associate Veterinarian (West Palm Beach)
M. N. WALKER, Ph.D., Associate Plant Pathologist (Leesburg)
W. B. SHIPPY, Ph.D., Assistant Plant Pathologist (Leesburg)
C. C. GOFF, M.S., Assistant Entomologist (Leesburg)
J. W. WILSON, Ph.D., Assistant Entomologist (Pierson)
*In cooperation with U. S. Department of Agriculture.























CONTENTS
PAGE

INTRODUCTION ..... ..................... .............. ... ........ ...... ........ 5

FIELD COUNTS ................................... ............-- .....-- ....-- .. 6

HIBERNATION CAGE EXPERIMENTS AND FIELD COUNTS 1926-27.................--- 9

HIBERNATION CAGE EXPERIMENTS AND FIELD COUNTS 1927-28.................... 16

HIBERNATION CAGE EXPERIMENTS AND FIELD COUNTS 1928-29-..--............... 24

HIBERNATION CAGE EXPERIMENTS AND FIELD COUNTS 1929-30.................... 31

SUMMARY OF HIBERNATION CAGE EXPERIMENTS AND FIELD COUNTS
1926-30 ........... ......... .................. ............ 38

COMPARISON OF EMERGENCE FROM HIBERNATION CAGES WITH FIELD
COUNTS .- ----- --............... -..... ..-- ........ ..................... 41

SUMMARY AND CONCLUSIONS .....-- --.. ........ ...................... 45

LITERATURE CITED ..................-.........-................... 47





















II


Fig. 2.-Hibernation cage equipped with automatic temperature
recording apparatus.


Iin


~541
----








DETERMINATION OF THE

WINTER SURVIVAL
OF THE COTTON BOLL WEEVIL

BY FIELD COUNTS

By
EDGAR F. GROSSMAN AND P. W. CALHOUN

INTRODUCTION
The successful winter survival of the cotton boll weevil (An-
thonomus grandis Boh.) made both natural and artificial control
methods employed in combating this injurious pest most diffi-
cult, for the cotton fields were reinfested by weevils emerging
from hibernation year after year. Consequently, extensive
studies of hibernation phenomena were conducted by entomolo-
gists (9, 10, 11, 12, 13)' in order to gain reasonably accurate
data concerning the winter survival of the boll weevil. Hiberna-
tion cages soon evolved from these preliminary studies and since
their general usage they have been accepted as a means of fore-
casting the boll weevil population which might be expected each
spring. The discrepancies between forecasts derived from hi-
bernation cage data and the actual infestation experienced led
to the examination of other means of forecasting boll weevil
abundance.
Counts of boll weevils hibernating in Spanish moss were next
strongly advocated in press bulletins and newspaper reports.
The senior author, however, was early discouraged by the incon-
sistency of the results obtained from counts of boll weevils in
Spanish moss. Large quantities of Spanish moss which sup-
posedly contained representative numbers of hibernating boll
weevils yielded very irregular counts. Although the theoretical
value of this method is apparent when Spanish moss is selected
from infested areas and the number of weevils per ton of Span-
ish moss is determined, nevertheless, the resulting counts are
often still more irregular and contradictory than the information
obtained from the hibernation cage method. The irregularities
Acknowledgments:-The authors are indebted to Mr. R. J. Hart for con-
ducting the field experiment at Baker, Florida, 1928, and Mr. R. M. Crown
for conducting the field experiment at Gainesville, Florida, in 1930.
'Figures in parentheses (italic) refer to "Literature Cited" in the back
of this bulletin.







Florida Agricultural Experiment Station


probably occur because the moss counts are evidently based on
one of two assumptions: either that boll weevils leave the cotton
fields in the autumn and disperse evenly throughout the Spanish
moss hanging on trees in the neighborhood of cotton fields, there-
by necessitating the collection of but a few moss samples, or that
the boll weevil disperses unevenly, necessitating the collection
of a large number of random samples of Spanish moss from
each district under observation for subsequent examination. The
first assumption is untenable. The second assumption necessi-
tates the exercise of extreme rigor in selecting a large number of
samples and thereby becomes cumbersome.
Since the accurate determination of the winter survival of the
boll weevil is an important factor in planning an effective method
of control, and since the methods in use were not satisfactory,
a critical examination of a new method of forecasting the abund-
ance of the boll weevil in the spring was undertaken. The new
method embraced field counts, which were found to be suitable
for determining the spring population of the boll weevil.

FIELD COUNTS

The necessity of determining both the approximate abundance
of the boll weevils surviving the winter and the time they en-
tered cotton fields, led to the consideration of a field count
method to gain the desired information. Such a method was de-
vised. Field counts were consequently started in 1926 (3). Sub-
sequent examination of the literature disclosed the fact that in
1906, Morgan (12) had counted boll weevils which appeared in
a field at Victoria, Texas. Morgan, however, followed a some-
what different procedure from that followed in Florida and,
unfortunately, his work was not continued. Fenton and Dunnam
(1, 2, 14) also reported on emergence as determined by field
counts conducted at Florence, S. C., in 1925 and 1926.
Field count experiments were inaugurated in Florida early in
February, 1926, when, in order to trap boll weevils leaving their
hibernation quarters, a row of 30 potted cotton plants was placed
at the edge of the woods. Each plant was examined daily for
weevils. A half-acre plot near the potted plants was prepared
for planting cotton, and a stand of about 2,500 plants was se-
cured early in April. Every day each one of these plants was
examined carefully for boll weevils until the end of April. At
this time the large number of growing squares made the search






Bulletin 233, Winter Survival of the Cotton Boll Weevil 7

rather difficult and so in the continued absence of boll weevils
the field was examined thereafter but three times each week.
It was not until May 10, however, that the first weevil was found.
The weevil was recorded and removed from the field, the same
procedure being followed throughout the season.
In October, 1925, a hibernation cage containing 5,000 weevils
(Fig. 2) was placed in the woods near the field used for the
counts. The cage served two purposes: first, the provision of a
means for the determination of the temperature in the center
of a large pile of Spanish moss in which the weevils hibernated
and a comparison of that temperature with the open air tempera-
tures; and second, a supply of weevils emerging from hiberna-
tion which could be marked and liberated in the woods. The
temperature in the center of the moss lagged behind the open
air temperature, usually becoming as warm as the air and often
several degrees colder. A number of weevils which were marked
with colored shellac were recovered in a nearby cotton field,
rarely more than two days after they had been liberated. The
significance of the information obtained from the recapture of
the weevils is of sufficient importance to indicate that the field
counts give reasonably accurate emergence data, and can be
compared with the data secured from hibernation cage tests.


' .i .. I i ,I ll, ,ll ll

Fig. 3.-Chart showing daily maximum and minimum temperatures, rain-
fall, and boll weevil appearance in a cotton field at Gainesville, Florida,
1926. Clear, partly cloudy, and cloudy days indicated by unshaded,
half-shaded, and full shaded small circles, respectively.
The recorded appearance of boll weevils which emerged from
their natural hibernation quarters in the woods is presented in
Table I. Additional information relative to temperature ahd







Florida Agricultural Experiment Station


rainfall is presented in Fig. 3. It is a significant fact that no
weevils were trapped during February, March, or April. All
hibernation cage work previously conducted in Florida yielded
some weevils in February and an appreciable number in March,
a maximum emergence in April being often reached.

TABLE I.-APPEARANCE OF BOLL WEEVILS WHICH HAD EMERGED FROM THEIR
NATURAL HIBERNATION QUARTERS IN THE WOODS, IN A COTTON FIELD AT
GAINESVILLE, FLORIDA, 1926, AS DETERMINED BY ACTUAL COUNTS.


Date Examined


May 10
12
14
17
19
21
23
25
27
29
31
June 2
4
6
8
10
12
14
16
18
20
22
24
26
28
30


Number of
Weevils Percent of
Found Total Found

1 0.2
1 0.2
3 0.5
0 0
4 0.6
5 0.8
3 0.5
18 2.8
12 1.9
7 1.1
2 0.3
6 0.9
14 2.2
28 4.4
32 5.0
44 6.8
27 4.2
59 9.1
46 7.2
35 5.5
87 13.5
58 9.0
61 9.4
41 6.4
16 2.5
32 5.0


Cumulative !
Number
Found

1
2
5
5
9
14
17
35
47
54
56
62
76
104
136
180
207
266
312
347
434
492
553
594
610
642


Cumulative
Percent

0.2
0.4
0.9
0.9
1.5
2.3
2.8
5.6
7.5
8.6
8.9
9.8
12.0
16.4
21.4
28.2
32.4
41.5
48.7
54.2
67.7
76.7
86.1
92.5
95.0
100.0


Although weevils were found in hibernation cages when the
minimum temperature dropped below 550F., the field yielded no
weevils at this temperature. Though the temperature during
the last week in May practically equalled that of summer
weather, but 8.9 percent of the total number of hibernated
weevils which were caught during the season appeared in the
field prior to June 1. The field was examined well into July,
but the records were not continued beyond the end of June be-
cause, in spite of the theoretically ideal conditions of rainfall
and temperature which continued during the latter part of June,
the weevil number decreased markedly. Furthermore, accurate
counts of the hibernated weevils were interfered with by field-







Bulletin 233, Winter Survival of the Cotton Boll Weevil 9

hatched weevils which infested the cotton at this time (7). Were
rainfall and temperature the sole factors which caused emerg-
ence from hibernation, the abundant rainfall which occurred dur-
ing the latter part of March and the early part of April, followed
by warm weather in April, would have caused a number of
weevils to emerge from hibernation during April and May.
Though weevils did not appear in the field, large numbers of
weevils had emerged from hibernation in all of the hibernation
cage series conducted in Florida heretofore under similar con-
ditions. Unfortunately there were no hibernation cages in use
during the season of 1925-26 which could be used for making a
direct comparison.

HIBERNATION CAGE EXPERIMENTS AND
FIELD COUNTS, 1926-27

During the 1925-26 season hibernation cage work was omitted
because the expense of operating cages was too great to warrant
continuation of work which, at best, was unsatisfactory. The
field count experiment conducted in 1926, however, pointed to
the necessity of additional cage work, since a direct comparison
of hibernation cage and field data was desired. As a conse-
quence, a large 8x8x8 foot screened cage was placed on the
ground in the woods and during the fall of 1926, 28,347 weevils
were placed in the cage which had been equipped with a large
quantity of Spanish moss and cornstalk debris, as shown in Fig.
4. Table II presents a record of the number of weevils used and
the dates on which they were placed in the cage.

TABLE II.-DATES ON WHICH BOLL WEEVILS WERE PLACED IN A HIBERNATION
CAGE AT GAINESVILLE, FLORIDA, 1926, AND THE NUMBER OF WEEVILS
PLACED IN THE CAGE ON EACH DATE.
S Number | Number
Date | of weevils Date of weevils

October 24 ....... 1,518 November 8 ........- 2,648
25.......... 991 9.......... 1,110
26 .......... 1,279 11.......... 3,703
28 .......... 876 12 .......... 1,505
29 .......-- 2,225 13-.......... 740
November 2.......... 3,473 16 .......- 197
3.......... 1,728 17 ........- 1,057
4.......... 762 18.......... 945
5.......... 666 19...-..... 1,627
6.......... 470 22......... 827

Total 28,347







Florida Agricultural Experiment Station


Fig. 4.-Copper-screened hibernation cage used at Gainesville, Florida,
1926-30, in boll weevil hibernation studies.

The usual boll weevil activity was in evidence throughout the
winter, a few weevils crawling about the cage from day to day,
with the exception of those days which registered a minimum
below freezing. Beginning February 28, all weevils which had
emerged from hibernation were captured and removed from the
cage. A detailed record of the subsequent daily emergence is
presented in Table III and a summary of the emergence is pre-
sented in Table IV. The last weevil emerged on July 26.








Bulletin 233, Winter Survival of the Cotton Boll Weevil 11

TABLE III.-DAILY RECORD OF BOLL WEEVILS EMERGING FROM A HIBERNA-
TION CAGE AT GAINESVILLE, FLORIDA, 1927.


Tot


Number of Weevils Emerging
Day
February March April May June July


1 ...... 42 27 18 31 0
2 ...... 10 20 35 145 0
3 ...... 8 29 50 3 0
4 ...... 10 56 51 5 0
5 ...... 6 35 138 4 0
6 ...... 11 23 56 2 0
7 .... 37 35 44 15 0
8 ...... 48 32 41 5 0
9 ...... 47 81 124 15 1
10 -..... 13 19 22 11 0
11 ...... 40 5 32 16 0
12 ...... 76 13 86 13 0
13 ...... 39 28 22 9 1
14 ...... 25 21 30 1 0
15 ...... 57 23 9 0 0
16 ...... 49 23 23 1 0
17 ...... 56 39 8 11 0
18 ...... 60 40 24 2 0
19 ...... 54 48 25 0 0
20 ...... 74 57 45 4 1
21 .... 62 16 33 3 0
22 ...... 10 31 26 3 0
23 ...... 6 2 12 1 0
24 ...... 1 22 24 0 0
25 ..... 1 24 12 0 0
26 ...... 18 27 43 0 1
27 ...... 24 35 24 1 0
28 258 14 47 11 0 0
29 ...... 21 43 18 1 0
30 ...... 17 52 24 0 0
31 ...-. 34 ...... 18 ...... 0

als 258 970 953 1,128 302 4


Aug.


0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0

0


TABLE IV.-SUMMARY OF BOLL WEEVIL EMERGENCE FROM A HIBERNATION
CAGE AT GAINESVILLE, FLORIDA, 1927.


Boll weevil emergence
Month Number Percent
weevils of Total

February* ........ 258 7.14
March .............. 970 26.83
April ................ 953 26.36
May .............. 1,128 31.20
June .................. 302 8.35
July .................. 4 0.11
August ............. 0 0

*One day only


Cumulative rate
of emergence

Date Percent

March 19 25
April 19 50
May 9 75
May 28 90
June 2 95
June 10 98
July 26 100








Florida Agricultural Experiment Station


Fig. 5.-Chart showing the daily maximum and minimum temperatures,
rainfall, and boll weevil emergence at Gainesville, Florida, 1927, from
a hibernation cage in which 28,347 weevils were placed during the
latter part of October and November, 1926. Clear, partly cloudy, and
cloudy days are indicated by unshaded, half shaded, and full shaded
small circles, respectively.

Fig. 5 presents the daily emergence of boll weevils from the
large hibernation cage placed on the ground in the woods in
1927. The emergence during the season was characterized by
an unusual uniformity, a very heavy emergence occurring dur-
ing March, April, and May, yielding 26.8, 26.4, and 31.2 percent
of the total emergence, respectively. A very unusual peak emerg-
ence for the year, however, occurred on June 2. After this date
but 3.5 percent more weevils emerged from hibernation. Only
four weevils appeared in July and none at all appeared in August.
KHntR hAtSL MN JOUJ







I A







Fig. 6.-Chart showing the daily maximum and minimum temperatures,
rainfall, and boll weevil appearance in a cotton field at Gainesville,
Florida, 1927. Clear, partly cloudy, and cloudy days are represented
by unshaded, half shaded, and full shaded small circles, respectively.







Bulletin 233, Winter Survival of the Cotton Boll Weevil 13

As in previous experiments when the minimum temperature
dropped below 550F., the emergence of weevils was considerably
checked. April and May had but two rainy days each, but after
these rains there was no subsequent appreciable increase in
weevil emergence.
In direct comparison with this emergence of the boll weevil
from a hibernation cage, there is the appearance of the weevil
from natural hibernation quarters in a cotton field adjoining
rather dense woods where there was a large quantity of Spanish
moss (4). Fig. 6 presents the record of the captured weevils
in tri-weekly periods. The temperature and the rainfall records
are taken from the United States Weather Bureau Station, lo-
cated about a half mile from the experimental field.
An early flush of weevils appeared in March, when 1.1 percent
of the total number of the weevils were captured in the field.
April yielded but an additional 0.2 percent weevils, while May
yielded 4.8 percent. Again, as in 1926, almost the entire num-
ber of weevils which were captured entered the cotton field dur-
ing June, the peak of the emergence falling on June 13. The
favorable weather conditions which brought so many weevils out
of hibernation in the cage during early spring failed to do so
in the field. A total of 1,188 weevils were captured in the three-
quarter acre field of about 3,500 cotton plants. As in 1926 potted
cotton plants were set out in the field to act as a trap for the
early weevils (Fig. 7). The early flush of weevils captured in
March, a total 12, was found on these potted plants. In all prob-
ability they had emerged from hibernation quarters located in
the debris piled up about the fence. Such light hibernation
quarters would tend to yield weevils at about the same time
that similar materials in hibernation cages yielded large num-
bers of them. Table V presents a detailed record of boll weevils
appearing in the selected three-quarter acre cotton field at
Gainesville, Florida, 1927.
Two additional field tests were conducted in 1927; one at Au-
cilla, Florida, and the other at Thomasville, Georgia. The test
plot at Aucilla was carefully prepared and the first weevil found
in the field appeared on April 28, just one day later than the first
weevil was found on the field-grown cotton plants at Gainesville.
The Aucilla test, however, did not progress successfully due to
unfortunate labor conditions.









14 Florida Agricultural Experiment Station

TABLE V.-APPEARANCE OF BOLL WEEVILS WHICH HAD EMERGED FROM THEIR
NATURAL HIBERNATION QUARTERS IN THE WOODS, IN A COTTON FIELD AT
GAINESVILLE, FLORIDA, 1927, AS DETERMINED BY ACTUAL COUNTS.
Number of Percent ulative Cumulative
Date Examined Weevils Number
Found ofFound

March 14................ 1 0.1 1 0.1
16............... 7 0.6 8 0.7
18 ............... 1 0.1 9 0.8
21---................ 1 0.1 10 0.9
23-----............. 1 0.1 11 1.0
26-............... 0 0 11 1.0
28.............. 1 0.1 12 1.1
30.............-.. 0 0 12 1.1
April 1-----............... 0 0 12 1.1
4................ 0 0 12 1.1
7...----.............- 0 0 12 1.1
9................ 1 0.1 13 1.2
11................ 0 0 13 1.2
13...------...-- 0 0 13 1.2
16----.......... 0 0 13 1.2
19...------. -- 0 13 1.2
22.............. 0 0 13 1.2
25.............. 0 0 13 1.2
27................ 1 0.1 14 1.3
29................ 0 0 14 1.3
May 2 ................ 0 0 14 1.3
4................ 0 0 14 1.3
6................ ----1 0.1 15 1.4
9................ -----2 0.2 17 1.6
11................ 8 0.7 25 2.3
13-----................ 3 0.3 28 2.6
16 ................ 3 0.3 31 2.9
18................ 0 0 31 2.9
20................ 2 0.2 33 3.1
23............... 1 0.1 34 3.2
25................ 4 0.3 38 3.5
27....---............ 8 0.7 46 4.2
30................ ----23 1.9 69 6.1
June 1........----........ 10 0.8 79 6.9
3 -----................ 33 2.8 112 9.7
6................ 57 4.8 169 14.5
8...------...--- 58 4.9 227 19.4
10................ 63 5.3 290 24.7
13................ 286 24.0 576 48.7
15............... 190 15.9 766 64.6
17................ 148 12.4 914 77.0
20................ 57 4.8 971 81.8
22.............. 67 5.6 1038 87.4
24................ 84 7.0 1122 94.4
27................ 19 1.6 1141 96.0
29................ 47 4.0 1188 100.0


The test at Thomasville yielded more information, though
weevil counts were made but once a week. About one-half acre,
2,500 plants, was examined but since the season's infestation was
very light, no great significance can be attached to the results








Bulletin 233, Winter Survival of the Cotton Boll Weevil 15


Fig. 7.-Potted cotton plants placed along the edge of boll weevil-infested
woods, Gainesville, Florida, 1927.

obtained. Table VI presents the weekly counts of boll weevils
captured in the field at Thomasville, Georgia, 1927.

TABLE VI.-APPEARANCE OF BOLL WEEVILS WHICH HAD EMERGED FROM
THEIR NATURAL HIBERNATION QUARTERS IN THE WOODS, IN A COTTON
FIELD AT THOMASVILLE, GEORGIA, 1927, AS DETERMINED BY ACTUAL
COUNTS.

Date of Weevils Percent Cumulative Cumulative
Examination Found of Total Number Percent
Found

May 18................ 0 0 0 0
25............... 3 4.2 3 4.2
June 1................1 5 6.9 8 11.1
8............-... 2 2.8 10 13.9
15................ 10 13.9 20 27.8
22-.......... 25* 34.7 45 62.5
July 1.........-.... 27* 37.5 72 100.0

*Field hatched boll weevils included.

Though these two tests present very meagre data, they indi-
cate, nevertheless, that the field appearance of boll weevils at
Gainesville is comparable to the emergence of the weevils in
fields farther north.







Florida Agricultural Experiment Station


HIBERNATION CAGE EXPERIMENTS
AND FIELD COUNTS, 1927-28

Following up the significant difference found to exist between
hibernation cage emergence and the appearance of boll weevils
in the field, additional tests were planned for the 1927-28 sea-
son. Five hibernation cages were prepared for the tests and a
small field was selected for the spring cotton planting. Three of
the cages were placed on the ground in the woods and contained
20,000, 5,000, and 5,000 weevils each. Two other cages with
5,000 weevils each were placed in the open field. One of the
latter was protected by a large roof to insure a continued dryness
of the hibernation material while the other cage was left un-
protected, thereby having the two cages represent conditions
wherein the hibernation materials were dry and wet, respective-
ly, to provide means for determining the actual effect of drought
on boll weevil survival and time of emergence. These two cages
were not compared with the appearance of the weevils in the
field as they yielded extremely irregular emergence data.
The field emergence test for 1928 (5) was conducted in the
same manner as the tests in 1926 and 1927. Potted cotton plants
were placed along the edge of the field early in February. Cot-


Fig. 8.-Field emergence plot, Gainesville, Florida, 1928.








Bulletin 233, Winter Survival of the Cotton Boll Weevil 17

ton was planted in the field at about the same time; cold weather,
however, necessitated several replantings. The potted plants
were examined three times each week until the field-grown cot-
ton was large enough to trap the boll weevil and by this time the
potted plants showed a determinate growth and produced no
more squares. Fig. 8 shows the field plot used in 1928.
No weevils were captured on the potted plants, and the first
weevil was found in the field on April 23. A record of the field
examinations is given in Table VII. The peak emergence occur-
red on June 15, when 67 or 17 percent of the 393 weevils which
were captured were recorded. Though a relatively small num-
ber of weevils were found, the data obtained were significant in
that they were similar to those obtained in 1926 and 1927 and
were at variance with the data obtained from the hibernation
cages which were in use at the same time.

TABLE VII.-APPEARANCE OF BOLL WEEVILS WHICH HAD EMERGED FROM;
THEIR NATURAL HIBERNATION QUARTERS IN THE WOODS, IN A COTTON FIELD
AT GAINESVILLE, FLORIDA, 1928, AS DETERMINED BY ACTUAL COUNTS.


Date Examined


April 23...............
25----
27..............
30 ................
M ay 2 ............
4 ..............
7.............
9--..............
11......-.........
1 4 ---------------
14..............
16..........
18 ..... ........
213..............
23.......
25... .........
28................
30.
June 1-
6 .............
June 1 -----------.----


13................
18................

20 ................
22--..............I
22....... .....
25................
27..............
29.. .....


Weevils
Found

2
6
2
0
1
1
0
1
5
6
1
2
2
0
1
11
3
21
40
27
28
12
9
67
59
27
30
15
7
7


Percent Cumulative
Percent Nu
of Total Found
Found

0.5 2
1.5 8
0.5 10
0 10
0.3 11
0.3 12
0 12
0.3 13
1.3 18
1.5 24
0.3 25
0.5 27
0.5 29
0 29
0.3 30
2.8 41
0.8 44
5.3 65
10.1 105
6.9 132
7.1 160
3.1 172
2.3 181
17.0 248
14.9 307
6.9 334
7.6 364
3.8 379
1.8 386
1.8 393


Cumulative
Percent

0.5
2.0
2.5
2.5
2.8
3.1
3.1
3.4
4.7
6.2
6.5
7.0
7.5
7.5
7.8
10.6
11.4
16.7
26.8
33.7
40.8
43.9
46.2
63.2
78.1
85.0
92.6
96.4
98.2
100.0


t


.







Florida Agricultural Experiment Station


A corroborative field emergence test was conducted at Baker,
Florida, in 1928. The plot was located near swampy land where
Murder Creek and Yellow River unite. This district has con-
sistently yielded greater boll weevil infestations than any other
cotton growing area in Okaloosa County. No boll weevils, how-
ever, were captured in April and May, a condition probably due
to the fact that great difficulty was encountered in planting cot-
ton sufficiently early to have plants large enough to trap the
weevils before the first week in June. Furthermore, the spring
of 1928 was cold and cotton got under way slowly throughout
the Florida cotton belt. Though very few weevils were found
altogether, more weevils were captured on June 15 and 21 than
on any other day, a condition which agrees with the peak emerg-
ences at Gainesville, Florida. A record of the emergence ob-
tained is presented in Table VIII.
TABLE VIII.-APPEARANCE OF BOLL WEEVILS WHICH HAD EMERGED FROM
THEIR NATURAL HIBERNATION QUARTERS IN THE WOODS, IN A COTTON FIELD
AT BAKER, FLORIDA, 1928, AS DETERMINED BY ACTUAL COUNTS.
Weevils Percent Total Total
Date Examined Found of Total to Date Percent

June 7---................ 7 12.2 7 12.2
9................ 3 5.4 10 17.6
11 ........-.. .. 0 0 10 17.6
13................ 5 8.9 15 26.5
15 ............... 8 14.4 23 40.9
18................ 4 7.1 27 48.0
21............... 8 14.4 35 62.4
23................ 5 8.9 40 71.3
25............... 2 3.6 42 74.9
27................ 6 10.8 48 85.7
30................ 4 7.1 52 92.8
July 2--............... 2 3.6 54 96.4
5-............... 2 3.6 56 100.0

Six counts after July 5 discarded because of danger of mixing with
field hatched weevils.
These two field tests conflict sharply in time of emergence
with the hibernation cage tests conducted at Gainesville, Florida,
1927-28. The cage tests included five cages, three in the woods
and two in an open field. All of the cages were equipped with
the same type of hibernation materials, Spanish moss and corn-
stalk debris. The Spanish moss was hung on branches erected
in the center of each cage, the corn stalks were packed about the
bottom of the cage and covered with an additional layer of Span-
ish moss. The dates on which boll weevils were placed in the
cages are given in Table IX.






Bulletin 233, Winter Survival of the Cotton Boll Weevil 19

TABLE IX.-DATES ON WHICH BOLL WEEVILS WERE PLACED IN HIBERNATION
CAGES AT GAINESVILLE, FLORIDA, 1927, AND THE NUMBER OF WEEVILS
PLACED IN EACH CAGE.
Number Boll Weevils Used
Date 1927 Cage Cage Cage i Cage Cage
No. 1 No. 2 No. 3 No. 4 No. 5
in Woods in Woods in Woods in Field in Field

October 19 .............. 477 477
20.... .......I 2,400 2,400
22............ 8,750 2,123 2,123
24 .............. 4,078
26.............. 3,678
28 .......... 1,409
31.............. 2,400
November |
1.............. 1,107 2,420
2............. 180
3.............. 978 1,725
9.....-..... .. 2,467
10-........... 808

TOTALS .............. 20,000 5,000 5,000 5,000 5,000


The daily emergence record for the five hibernation cages is
given in Table X. Cage 1 represents the large cage pictured in
Fig. 4, containing 20,000 weevils; Cages 2 and 3, with 5,000
weevils each, represent the small cages on the ground in the
woods; and cages 4 and 5, with 5,000 weevils each, represent
small cages in the open field. It is an interesting fact that
emergence was completed in the large cage in the woods on
June 28, while the smaller ones in the woods continued to yield
weevils until July 16. The open field cages yielded no more
weevils after one weevil appeared on May 10. As in the previous
year, a large number of weevils were captured on the first day
the cages were examined; the number captured on the first day
this season, however, was not equalled on any succeeding day
throughout the remainder of the period of emergence.
The summary of boll weevil emergence from the hibernation
cages observed in 1928 and the record of the dates on which
specified percent of the total number of weevils emerged, Tables
XI and XII, agree with previously conducted cage work. Points
of interest, however, include the fact that but 2.44 percent of
20,000 weevils placed in the large cage in the woods were cap-
tured while 11.24 and 5.24 percent, respectively, of 5,000 weevils
placed in each of the two small cages in the woods were observed




TABLE X.-DAILY COMBINED RECORD OF BOLL WEEVILS EMERGING FROM HIBERNATION IN THREE SERIES OF CAGES, AT GAINES-
VILLE, FLORIDA, 1928.


Number of weevils emerging


March


Day


u !U
97 63
2........ 6 14
3........ 3 7
4........ 16 17
5 ....... 23 27
6.....--- 1 6
7........ 14 17
8. ..... 9 16
9 .....- 18 20
10....... 20 15
11....... 28 18
12....... 5 0
13........ 14 21
14....... 15 9
15 ....... 19 15
16....... 6 4
17....... 3 4
18...... 4 0
19...... 1 0
20 ..... 0 2
21....... 1 2
22....... 0 5
23....... 3 4
24 ...... 1 11
25 ........ 3 1
26........ 5 3
27........ 11 26
28 ........ 5 5
29........ 8 9
30........ 4 3
31........ 1 1
Totals ........ 344 345


April







19 0 2 I 1
1 7 3 3
2 1 4 0
3 4 5 0
3 5 7 2
2 9 8 1
5 6 20 1
2 3 16 3
6 5 8 0
4 0 0 0
0 2 2 0
0 1 13 0
5 11 10 1
2 8 10 1
2 3 0 0
0 1 0 0
0 0 2 0
0 6 2 0
0 3 12 1
0 4 3 0
0 2 7 1
0 3 2 0
1 9 9 0
0 2 8 0
0 1 6 1
0 1 1 0
1 1 3 0
0 0 0 0
2 1 0 0
1 1 1 0
0 .... -
61 100 164 16


2

2
2
1
0
2
0
0
3
3
2
2
1
0
4
4
4
1
1
3
0
0
0
2
1
0
0
0
0
0
0


May







2 0 0
6 0 1
5 0 0
8 0 0
5 0 0
7 0 0
3 0 0
0 0 0
3 0 0
9 1 0
0 0 0
15 0 0
4 0 0
5 0 1
5 0 0
3 0 0
3 0 0
7 0 0
13 0 0
8 0 0
6 0 0
0 0 0
1 0 0
22 0 0
18 0 0
3 0 0
4 0 0
4 0 1
14 0 0
12 0 0
5 0 ....


S40 200 I


1 3 1


June







1i 0 0
CO






z 0 0

1 0 0
7 0 0
1 0 0
6 0 0
0 0 0
1 0 0
1 0 0
1 0 0
7 0 0
1 0 0
5 0 0
2 0 0
2 0 0
8 0 0
0 0 0
6 0 0
21 0 0


11 0 0
2 0 0
0 0 0
0 0 0
0 0 0
2 0 0
1 0 0


0 0 0
1 0 0
0 0 0
7 0 0
6 0 O0
0 0 0
2 0 0
1 0 0
0
112 0 0


July N



0 0




0 0

1 0
0 0
0 0 .
0 0
0 0
0 0


0 0 0
1 0
0 0 s




0 0 2
0 0

0 0
0 0 O
01 0
0 0
0 0
0 0 Z
0 0
0 0
0 0
0 0
0 0
0 0
0 0

0 0
0 0


3_ 1 0






Bulletin 233, Winter Survival of the Cotton Boll Weevil 21

to emerge from hibernation. (This great discrepancy between
the emergence records of these two sets of cages can be partly
attributed to the presence of lizards (Sceloporus spinosus)
which gained entrance into the large cage and ate a large num-
ber of weevils before they themselves were captured. The cap-
tured lizards yielded feces showing traces of boll weevil elytra,
and upon being offered live boll weevils ate them greedily.) The
open field cages yielded but 29, or 0.58 percent, and 49, or 0.98
percent, of the 5,000 weevils used, respectively. In all the cage
series, 50 percent of the weevils had emerged by March 15, and
in all except one, 90 percent had emerged in April, a decidedly
different condition from that found in the field emergence test.


II 1h I I .. I I .
Fig. 9.-Chart showing the daily maximum and minimum temperatures,
rainfall, and boll weevil emergence at Gainesville, Florida, 1928, from
two hibernation cages containing 5,000 weevils each, located in an open
field. Clear, partly cloudy, and cloudy days are indicated by unshaded,
half shaded, and full shaded small circles, respectively.

The emergence of boll weevils from the two cages placed in
the open field is presented in Fig. 9. The relatively heavy emerg-
ence during the cold weather which occurred during the first
week of March is rather unusual, though as a rule emergence
from cages in the open is earlier than that found in cages placed
in the woods. The correlation between drops of the temperature
below 550F. and a marked reduction in weevil emergence is
lacking in this cage series, though the data cannot be considered
indicative of a lack of correlation, due to the small total number
of weevils noted to have emerged, when only 78, or 0.78 percent,
of the 10,000 placed in the cages emerged. The abundant rain-
fall which occurred during the entire period eliminated the study










TABLE XI.-BOLL WEEVIL EMERGENCE BY MONTHS FROM HIBERNATION CAGES AT GAINESVILLE, FLORIDA, 1928.
March April May June July Total Emergence No Boll Total
WPeevils Percent
Cages Weevils IPercent Weevils Percent Weevils Percent Weevils Percent Weevils Percent Number Percent Used Emerged

Woods No. 1 344 70.63 100 20.54 40 8.21 3 .62 0 0 487 100 20,000 2.44
Woods No. 2 173 30.78 100 17.79 175 31.14 111 19.76 3 .53 562 100 5,000 11.24
Woods No. 3 172 65.65 64 24.43 25 9.54 1 .38 0 0 262 100 5,000 5.24
Field No. 4 25 86.21 4 13.79 0 0 0 0 0 0 29 100 5,000 0.58
Field No. 5 36 73.47 12 24.49 1 2.04 0 0 0 0 49 100 5,000 0.98








TABLE XII.-DATES ON WHICH SPECIFIED PERCENT OF THE TOTAL NUMBER OF BOLL WEEVILS HAD EMERGED
FROM HIBERNATION CAGES AT GAINESVILLE, FLORIDA, 1928.
Percent Emergence and Date Completed
Cages 25 Percent 50 Percent 75 Percent 90 Percent 95 Percent 98 Percent 100 Percent

Woods No. 1.... March 4 March 13 April 7 April 23 May 13 May 18 June 28
Woods No. 2...... March 24 May 3 May 29 June 14 June 16 June 27 July 16
Woods No. 3 ... March 7 March 15 April 9 April 27 May 12 1 May 19 June 15
Field No. 4...... March 1 March 9 March 14 April 2 April 5 April 21 April 21
Field No. 5 ...... March 3 March 9 April 1 April 8 April 19 I April 25 | May 10








Bulletin 233, Winter Survival of the Cotton Boll Weevil 23


APMl SH
10 m M 18 m1


"IS


Jji


Fig. 10.-Chart showing daily maximum and minimum temperatures, rain-
fall, and boll weevil emergence at Gainesville, Florida, 1928, from two
hibernation cages containing 5,000 weevils each, located on the ground
in the woods. Clear, partly cloudy, and cloudy days indicated by un-
shaded, half shaded, and full shaded circles, respectively.

of humidity as a factor which might induce either rapid or
retarded emergence.
The two cages containing 5,000 weevils each which were plac-
ed on the ground in the woods, however, yielded a representative
number of weevils. Fig. 10 shows that after the high emergence
during the first half of March, a fairly uniform number of
weevils appeared daily, reacting but slightly to the possible re-
tarding effect of low temperature. An unusual June emergence
for hibernation cages took place in this series. This emergence
furthermore was preceded by sufficient warm weather during

MAdCH sPadd a uV JUNe
i^ 0 5 W 5 I IS S5s

NAK V

V .









,-f a b .,, a ern l i n .1 I III

Fig. 11.-Chart showing the daily maximum and minimum temperatures,
rainfall, and boll weevil appearance in a cotton field at Gainesville,
Florida, 1928. Clear, partly cloudy, and cloudy days indicated by un-
shaded, half shaded, and full shaded circles, respectively.


II I ii I.iIl


ur*
ouau
i
;:" ~
'


'" ~
j-
ii
,

I'-i ''


I


. 1| 11 .R Il .wL| | = | = .| .. .|.|.o|I|. |.


I


JUNE
T U


/ib'I


; i







Florida Agricultural Experiment Station


May which would ordinarily have largely completed the emerg-
ence by the end of that month.
A comparison of Figures 11 and 12 shows clearly the differ-
ence between boll weevil emergence from hibernation cages and
the appearance of the weevil in the field. But 10 weevils, or 2.5
percent, of the total number recorded appeared in the field dur-
ing April. An additional 34 or 8.9 percent, of the total number
emerged during May, and the balance, 88.6 percent, appeared
in June. During the same period and under the same tempera-


I I I I L =.


Fig. 12.-Chart showing the daily maximum and minimum temperatures,
rainfall, and boll weevil emergence at Gainesville, Florida, 1928, from
a hibernation cage containing 20,000 weevils, located on the ground
in the woods. Clear, partly cloudy, and cloudy days represented by un-
shaded, half shaded, and full shaded circles, respectively.

ture and moisture conditions, 91.2 percent of the emerged
weevils appeared by the end of April in a hibernation cage into
which 20,000 weevils had been introduced. May brought an ad-
ditional 8.2 percent out and in June the remainder, or 0.62 per-
cent of the total number to emerge, appeared.

HIBERNATION CAGE EXPERIMENTS
AND FIELD COUNTS, 1928-29

Though the differences between the emergence of boll weevils
from hibernation in cages and their appearance in the field were
marked in the comparative experiments conducted during the
past three years, still another set of tests was inaugurated dur-
ing the 1928-29 season at Gainesville, Florida. In the fall of
1928, three hibernation cages were prepared for boll weevil hi-
bernation and a small field located near woods known to harbor







Bulletin 233, Winter Survival of the Cotton Boll Weevil 25

weevils was selected for spring cotton planting. The cages were
replaced on the ground in the same location and under the same
conditions in which they were used during the past three years.
Since 20,000 weevils were used in the large cage, together with
3,000 weevils in each of the two small cages, it was thought that
a sufficient number of weevils were employed to offset the cage
irregularities which usually occur.

TABLE XIII.--APPEARANCE OF BOLL WEEVILS WHICH HAD EMERGED FROM
THEIR NATURAL HIBERNATION QUARTERS IN THE WOODS, IN A COTTON
FIELD AT GAINESVILLE, FLORIDA, 1929, AS DETERMINED BY ACTUAL COUNTS.
Wevils Pent Cumulative Cumulative
Date Examined Feeod of Toal Number Percent
Found of Total Fon Fon
Found Found

April 29............... 0 0 0 0
May 1................ 2 0.4 2 0.4
3 ................ 0 0 2 0.4
6..-............. 2 0.4 4 0.8
8 ................ 11 2.2 15 3.0
10................ 10 2.0 25 5.0
13................ 3 0.6 28 5.6
15............. 2 0.4 30 6.0
17................ 3 0.6 33 6.6
20.............. 9 1.8 42 8.4
22............... 13 2.6 55 11.0
24......... ...... 10 2.0 65 13.0
27................ 21 4.2 86 17.2
29........ ..... 10 I 2.0 96 19.2
31.............. 8 1.6 104 20.8
June 3................ 117 23.4 221 44.2
5................ 25 5.0 246 49.2
7..............1 40 8.0 286 57.2
10.....-.....i... 56 11.2 342 68.4
12............... 6 1.2 348 69.6
14............j. 37 7.4 385 77.0
17.............. 22 4.4 407 81.4
19........ ..... 19 3.8 426 85.2
21...-.....-...... 19 3.8 445 89.0
24............... 20 4.0 465 93.0
26............... 5 1.0 470 94.0
28................ 12 2.4 482 96.4
July 1............... 12 2.4 494 98.8
3................ 6 1.2 500 100.0


As in the previous field tests, cotton seed were planted early
in February and at the same time potted cotton plants were
placed along the edge of the small field selected for the boll
weevil counts (8). The potted plants were examined three times
a week until the field grown plants were large enough to harbor
boll weevils, at which time the potted plants were removed. No
weevils were found on the potted plants. The first weevil cap-
tured in the field was recorded on May 1, and the highest count







Florida Agricultural Experiment Station


was recorded on June 3, when 117, or 23.4 percent of the total
number of captured weevils (500), were found in the field. This
was the earliest peak to occur during the four annual tests.
With the exception of the rather early emergence peak, the field
data corresponded with those secured during the previous years
and continued to be at variance with the hibernation cage emerg-
ence data secured in the past tests as well as those secured dur-
ing the present one. An itemized record of the field emergence
is presented in Table XIII.
Beginning on October 24, and continuing through November 3,
boll weevils were introduced into the hibernation cages placed
on the ground in the woods. The hibernation materials with
which the cages were equipped consisted of Spanish moss and
cornstalk debris arranged in the manner adopted for all of the
earlier cage experiments. The dates on which the weevils were
introduced into the cages are recorded in Table XIV.

TABLE XIV.-DATES ON WHICH BOLL WEEVILS WERE PLACED IN HIBERNA-
TION CAGES AT GAINESVILLE, FLORIDA, 1928, AND THE NUMBER OF WEEVILS
PLACED IN EACH CAGE.
Number Boll Weevils Used
Date 1928 ...
Cage 1 Cage 2 Cage 3

October 24......................... 3,000
25.......................... 3,100
26.........................-- 2,940
27------........................ 1,550
29.......................... 2,420
30.........................--- 5,975
31...............-.......... 2,216 580
November 1---.............-..........307
2 -----............. ------ 2,955
3-.......................... 957

Totals ..............-................... 20,000 _3,000 3,000

The daily emergence record for the three cages employed in
the 1928-29 series of cage tests is presented in Table XV. The
large cage containing 20,000 weevils yielded the last weevil
which emerged from hibernation on September 7, thereby estab-
lishing a new Florida record for weevil longevity in a hibernation
cage, since the weevil lived at least 308 days in the cage without
food and spent at least 191 days of this time in complete hiberna-
tion. The previous record for time spent in a hibernation cage
in Florida was 267 days (6). The two small cages yielded the
last weevil on August 12 and July 11, respectively.




TABLE XV.-DAILY RECORD OF BOLL WEEVILS EMERGING FROM HIBERNATION IN THREE CAGES AT GAINESVILLE, FLORIDA, 1929.
Cages Nos. 1 and 2 were supplied with weevils captured in Florida, Cage No. 3 with weevils captured in Georgia.
Number of Emerged Weevils


March April
Day *- | c. .
SoM UM

1 215 11 26 53 13
2 9 16 4 34 3
3 39 15 15 9 6
4 87 21 15 11 9
5 11 2 1 29 16
6 7 0 1 50 16
7 20 2 2 42 23
8 7 0 1 50 26
9 16 2 2 78 21
10 2 0 0 61 29
11 2 1 1 191 11
12 2 0 0 141 9
13 24 0 3 220 30
14 22 4 6 164 12
15 53 7 11 32 1
16 54 21 25 8 2
17 8 3 1 2 2
18 15 2 3 27 10
19 29 7 5 28 10
20 18 1 1 26 11
21 158 10 9 52 7
22 54 12 8 78 13
23 26 3 8 24 8
24 72 15 19 66 5
25 41 5 20 55 13
26 51 7 11 38 3
27 39 9 9 23 11
28 17 5 23 22 5
29 42 3 12 24 1
30 264 17 19 20 3
31 69 6 21 .... ....
Totalsl 1473 1 207 | 282 ( 1658 | 329 (
*Cages not examined.


May June July August September


Cd al I cd W Cd Cd W C3 CS d C d i

12 19 3 3 128 30 4 17 3 0 4 0 0 1 0 0
4 52 9 2 114 18 3 17 1 1 1 0 0 0 0 0
13 8 2 1 27 6 3 12 0 0 0 0 0 0 0 0
16 7 3 0 6 2 0 9 0 0 0 0 0 0 0 0
31 23 0 1 30 1 0 11 1 0 0 0 0 0 0 0
29 329 23 3 31 5 0 5 0 0 0 0 0
39 146 13 3 15 5 1 5 0 0 3 0 0 1 0 0
55 35 8 2 19 2 0 23 5 0 0 0 0 0 0
49 10 4 1 28 6 0 9 2 0 0 0
51 11 3 0 20 3 0 7 1 1 0 0 0
24 5 1 1 30 2 1 3 1 1 0 0 0
14 12 1 1 15 5 2 8 0 0 2 1 0 0 0 0
15 13 4 2 36 3 3 6 1 0 0 0 0 0 0 0
14 15 4 0 6 1 1 3 1 0 0 0 0
3 18 1 1 18 3 0 4 1 0 1 0 0 0 0 0
0 17 1 3 6 1 0 6 0 0 0 0 0 0 0 0
2 18 0 0 23 4 1 4 0 0 0 0 .. ....
7 21 7 3 88 7 4 19 2 0 0 0 0 ......
2 84 10 3 18 3 1 4 0 0 0 0 0 ........
1 17 3 1 16 6 0 1 0 0 0 0 0 ........
1 261 37 4 24 3 0 3 0 0 0 0 0 .....
4 23 6 3 14 0 1 5 1 1 0 0 ........
5 8 6 1 13 0 0 7 0 0 0 0 .......
1 17 3 1 8 1 0 4 0 0 0 0 0 ........
2 20 0 1 46 5 0 8 0 0 0 0 0 ........
6 14 2 0 23 3 0 1 0 0 0 0 0 ........
3 14 1 2 96 8 0 4 0 0 0 0 0 ...
0 23 8 0 23 1 0 0 0 0 ......
3 7 4 0 28 7 0 2 0 0 0 0 0 ........
1 29 2 1 13 2 0 2 2 0 1 0 0 .........
168 5 1 ... .... .... 5 0 0 0 0 .... ....
407 1444 174 45 962 1431 2512141 22 | 3 12 1 0 121 0 0








TABLE XVI.-DATES ON WHICH SPECIFIED PERCENT OF THE TOTAL NUMBER OF BOLL WEEVILS HAD EMERGED FROM HIBERNA-
TION CAGES AT GAINESVILLE, FLORIDA, 1929.

Cages Dates on Which Boll Weevils Emerged
Cas 25 Percent 50 Percent 1 75 Percent 90 Percent 95 Percent 98 Percent | 100 Percent

No. 1....................... March 31 April 23 May 26 June 18 June 28 July 10 Sept. 7
No. 2...................... April 1 April 18 May 21 June 10 June 25 July 5 Aug. 12
No. 3....................... March 26 April 6 April 10 April 29 May 21 June 12 July 11
June 121 July11


TABLE XVII.-SUMMARY OF BOLL WEEVIL EMERGENCE FROM HIBERNATION CAGES AT GAINESVILLE, FLORIDA, 1929.

Emergence
March April May June July August Totals Total




No. 1 1473 25.5 1658 28.8 1444 25.1 962 16.7 214 3.7 1 .20.2 76 100 20,000 28.83

No. 2 207 23.6 329 37.6 174 19.9 143 16.3 22 2.5 1 .1 876 100 3,000 29.20
No. 3 282 37.0 407 53.4 45 5.9 25 3.3 3 0.4 0 0 762 100 3,000 25.40






Bulletin 233, Winter Survival of the Cotton Boll Weevil 29

A summary of the hibernation cage emergence at Gainesville,
Florida, is presented in Table XVI, and a record of the dates on
which 25, 50, 75, 90, 95, 98, and 100 percent, respectively, of the
total emergence of boll weevils from hibernation in the cages
occurred is given in Table XVII.
Results obtained with this series of cages coincide with those
obtained with cages placed on the ground in the woods during
former years, the usual high rate of emergence having taken
place during the months of March and April, and the greatest
total monthly emergence occurring in April. The total number
of weevils emerging from each cage is also noteworthy, there
being but a slight variation of the totals among the three cages
used. Five thousand seven hundred and sixty-five, or 28.8 per-
cent of the 20,000 weevils placed in one cage, emerged as com-
pared with 876, or 29.2 percent, of 3,000 weevils in one of the
two smaller cages, and 762, or 25.4 percent, of 3,000 weevils in
the other. Emergence was completed earlier in the cage into
which weevils shipped from Georgia were placed than in the
other cages which contained weevils collected in Florida.
Figure 13, a chart showing the emergence of boll weevils from
one of the smaller hibernation cages containing 3,000 weevils on
the ground in the woods, indicates that there was a fairly uni-
form emergence from March through June with but one ex-
tended group of high daily emergences. The peak emergence
in May was unusually late and occurred during a group of rainy
days. As in all other cage experiments, when the temperature
dropped to points below 550F., a corresponding reduction in the
emergence rate appeared. The long period of relatively dry
weather, extending from March 1 to April 14, failed to check
weevil emergence.
The emergence of the weevils shipped from Georgia and placed
in a small cage on the ground in the woods, however, was not
uniform (Fig. 14), a decided flush of emergence occurring dur-
ing the first part of April. Furthermore, the April flushes in
this cage were not followed by a peak emergence, but few weevils
having emerged after the middle of the month. The periods of
low temperature were accompanied by a noticeably reduced
emergence rate. Though peak emergences in the other cages
of this series occurred simultaneously with a relatively heavy
rainfall, such was not the case in this cage. The July emerg-
ence, however, was similar to that of the majority of hiberna-
tion cages.















Fig. 13.-Chart (right) showing the
daily maximum and minimum
temperatures, rainfall, and boll
weevil emergence at Gainesville,
Florida, 1929, from a hiberna-
tion cage containing 3,000
weevils captured in Florida.
The cage was located on the
ground in the woods. Clear,
partly cloudy, and cloudy days
are indicated by unshaded, half
shaded, and full shaded circles,
respectively.


5 91 1 1II I 1 1. 1 5 2 .1 r 1. 11















.25 1
II ssII


IO II ii .i illm ii~m II~ 1.11/////l /~--lll~~~c I.I
"IUI~~~~~~Y ~ ~ **,:v//~/~///~~ ~~~


i ,



5 tO 105
~I i \


Fig. 14.-Chart (left) showing the
daily maximum and minimum
temperatures, rainfall, and boll
weevil emergence at Gainesville,
Florida, 1929, from a hiberna-
tion cage containing 3,000
weevils captured in Georgia.
The cage was located on the
ground in the woods. Clear,
partly cloudy, and cloudy days
are indicated by unshaded, half
shaded and full shaded circles,
respectively.






Bulletin 233, Winter Survival of the Cotton Boll Weevil 31

The emergence from the cage containing 20,000 weevils which
were captured in Florida (Fig. 15) was very similar to that of
the smaller cage containing 3,000 weevils which were also cap-
tured in Florida. The emergence in the large cage, however, was
a little later, yielding weevils on more days in June and July
than the smaller cage. As in the other two cages the emergence
during the first part of April was heavy, though the peak
emergence did not occur until May 6. In this cage also, the lower
temperatures reduced the number of emerging weevils and the
rainfall occurring during May 19-21 was attended by a relatively
large percent emergence.
The chart (Fig. 16) showing the arrival of boll weevils in the
cotton field, however, is strikingly different from the charts pic-
turing the emergence of weevils from the hibernation cages.
In the field no weevils appeared during March and April, and
comparatively few appeared during May, whereas the cages
yielded over 75 percent of the total number of emerged weevils
during the same period. Following the peak of appearance in
the field which occurred on June 3, there is a gradual tapering off
until by the end of the month very few weevils entered the
field. This field test, with the exception of the earliness of the
peak of appearance, agrees with the field counts conducted dur-
ing the preceding three years. The cool weather occurring on
June 11-12 appeared to have reduced the number of weevils ap-
pearing in the field, while the cold weather of May 3-4 completely
checked their appearance, indicating that there appears to be
more of a correlation between weevil emergence and low tem-
perature in the field than in the cages.

HIBERNATION CAGE EXPERIMENTS
AND FIELD COUNTS, 1929-30

A final series of tests was designed to compare boll weevil
emergence from hibernation cages, with their appearance in a
cotton field at Gainesville, Florida, in the fall of 1929. The test
included four cages which were placed on the ground in the
woods and a small plot of land in a boll weevil infested field in
which cotton was planted late in February, 1930. Potted cotton
plants were not used. An early stand of cotton was successfully
raised and as a consequence the absence of the potted cotton
probably did not render the early weevil appearance data incom-
plete. Each plant in the field was examined tri-weekly. The












Fig. 15.-Chart (right) showing the
daily maximum and minimum
temperatures, rainfall, and boll
weevil emergence at Gainesville,
Florida, 1929, from a hiberna-
tion cage containing 20,000
weevils captured in Florida.
The cage was located on the
ground in the woods. Clear,
partly cloudy, and cloudy days
are indicated by unshaded, half-
shaded, and full shaded small
circles, respectively.


das cuzg~ uY*~*;E oIcOf.4acraatUC tlXOY


a
S 20


ii I .i. ii I ii


,,. l .,, 11 .. I ... .




V --


1] ..III l L. -i I 2 1 1


MARCH AIRI" mAy JURY




..i .- i
. ',"- 1 *, ... ,, ,


2 1


I I I


I f *- II II i.


Fig. 16.-Chart (left) showing the daily max-
imum and minimum temperatures, rain-
fall, and boll weevil appearance in a cot-
ton field at Gainesville, Florida, 1929.
Clear, partly cloudy, and cloudy days are
indicated by unshaded, half shaded, and
full shaded small circles, respectively.








Bulletin 233, Winter Survival of the Cotton Boll Weevil 33

first weevil was captured on April 28, and the peak of appear-
ance occurred on June 11, both occurrences corresponding with
the results of tests conducted during the preceding four years.
The total number of weevils captured was very small but when
the data are compared with those already obtained they are of
sufficient comparative significance to be included in this report.
An itemized list of the weevils captured in the test field is pre-
sented in Table XVIII.

TABLE XVIII.-APPEARANCE OF BOLL WEEVILS WHICH HAD EMERGED FROM
THEIR NATURAL HIBERNATION QUARTERS IN THE WOODS, IN A COTTON
FIELD AT GAINESVILLE, FLORIDA, 1930, AS DETERMINED BY ACTUAL COUNT.


Date of
Examination

A pril 28................
30...............
M ay 2................
5.... ............
7...............---
9----...............
12....--.......- .
14................
16 ..............-
19................
21 ..............
21 .-.
23...............
26........ ...
28.............
30 ..............
June 2..............
4....- .........
6..............
9 ................
11................
13...............
16...........
18.......... ..
20..............
23 -...........
25................
I


Weevils
Found

1
0
0
0
0
0
0
0
0
1
1
0
8
1
8
2
1
6
6
13
6
5
7
4
5
1


Percent Cumulative Cumulative
of Total Number Percent


1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
1.3
2.6
3.9
3.9
14.4
15.7
26.2
28.8
30.1
38.0
45.9
63.1
71.0
77.6
86.8
92.1
98.7
100.0


The hibernation cage tests consisted of four cages placed on
the ground in the woods in the immediate vicinity of the other
cage experiments which had been conducted at Gainesville, Flor-
ida. The cages were equipped with the same hibernation ma-
terials used in all of the previously conducted experiments. The
weevils, however, were placed in the cages several weeks earlier
than usual, as indicated in Table XIX.
The emergence data of the weevils quitting hibernation in
each cage are presented in Table XX. Though the character of







Florida Agricultural Experiment Station


the emergence observed in each of the four cages was fairly uni-
form, one cage yielded a weevil four weeks after the day on
which the last weevil obtained from the other cages appeared.
All of the cages, however, yielded the last emerging weevils
very early in the season, a condition probably brought about by
the earliness of the weevil introduction into the cages, which
condition, in turn, may be thought to have so reduced the hardi-
ness of the weevils that the weakened ones which would norm-
ally have emerged later in the spring failed to emerge at all.

TABLE XIX.-DATES ON WHICH BOLL WEEVILS WERE PLACED IN HIBERNA-
TION CAGES AT GAINESVILLE, FLORIDA, 1929, AND THE NUMBER OF WEEVILS
PLACED IN EACH CAGE.
De Number Boll Weevils Used
Date
Cage 1 Cage 2 Cage 3 Cage 4

October 1...................... 529 594 500 520
5....................... 1,400 1,300 985 1,105
6....................... 1,200 1,200 1,565 1,200
7....................... 500 500 500 527
8....................... 300 600 600 600
9........................ 2,071 2,100 1,500 1,200

Totals ......................... 6,000 6,294 5,650 5,152


Tables XXI and XXII present a summary of the weevil emerg-
ence from the 1929-30 hibernation cages and a record of the
dates on which 25, 50, 75, 90, 95, 98, and 100 percent, respective-
ly, of the total emergence had occurred. In three of the four
cages emergence was completed in May and the fourth cage
yielded but 2.0 percent subsequent emergence. Cage 1 yielded
100 boll weevils, or 1.67 percent of 6,000 placed in hibernation;
Cage 2, 194, or 3.08 percent of 6,294 weevils; Cage 3, 203, or
3.59 percent of 5,650 weevils; and Cage 4, 263, or 5.10 percent
of 5,152 weevils. Combining the data, 760, or 3.29 percent of the
23,096 weevils placed in hibernation, emerged. The maximum
emergence for a monthly period occurred in March in one cage;
April in two cages, and May in one cage. The small total emerg-
ence observed in each of the four individual cages would hardly
be of significant value unless the data could be used in compar-
ison with previously conducted experiments.
The chart of the hibernation cage emergence, presented in
Fig. 17, is similar to many of the charts already presented, show-
ing relatively heavy and uniform emergence during March,




TABLE XX.-DAILY RECORD OF THE EMERGENCE OF BOLL WEEVILS FROM HIBERNATION CAGES AT GAINESVILLE, FLORIDA, 1930.
Number of Emerged Weevils
March April May June
Day r0 0 0 .. e 0 0I D |


1... 6 35 16 26 2 0 10 2 0 0 1 3 0 0 0 0 a
2 .......... 1 0 2 3 1 2 2 0 1 2 4 2 0 0 0 0 4
3.......... 0 0 0 0 2 6 0 2 0 0 2 1 0 0 0 0
4.......... 0 0 0 0 0 1 0 1 3 0 0 2 1 0 0 0
5......... 0 0 0 1 2 3 6 9 1 2 0 2 0 0 0 0
6........ 0 0 2 2 4 7 5 5 3 0 5 3 0 0 0 0
7 ........ 0 0 1 1 0 1 1 7 1 4 3 3 0 0 0 0
8 ....... 4 0 2 0 0 1 0 8 4 4 10 0 0 0 0
9 ........ 1 0 0 1 0 1 2 3 1 3 7 8 0 0 0 0
10 ........ 0 2 3 4 3 0 3 1 2 3 4 1 0 0 0 0
11 ...... 0 1 0 1 0 1 1 2 2 3 4 3 0 0 0 0 .
12 ........ 1 2 1 4 2 1 2 2 2 0 2 6 0 0 0 0
13 ...... 0 2 1 0 2 1 8 13 1 0 1 0 0 0 0 0
14...... ...... .... .. .... 0 7 6 5 1 4 2 2 0 0 0 0 o
15.......... .... 1 1 6 5 2 1 0 2 0 0 0 0
16.......... 2 0 0 0 0 2 3 5 1 4 0 2 0 0 0 0
17 ........ 1 10 2 6 1 2 2 10 3 3 3 4 0 0 0 0
18......... 3 17 8 32 1 5 12 15 0 1 0 1 0 0 0 0
19......... 3 4 2 0 0 1 1 0 2 5 0 0 0 0 0 0
20.. ...... 3 2 9 9 1 7 6 10 2 1 1 0 0 0 0 0 -
21.......... 2 2 5 3 2 3 10 3 1 0 0 0 0 0 0 0
22......... 0 0 0 0 0 0 2 3 4 0 0 0 0 0 0 0
23 .......0.. 0 1 0 1 0 2 2 2 1 0 1 0 0 0 0
24......... 1 0 1 1 0 0 0 0 0 2 0 0 0 0 0 0
25.......... 2 8 4 1 0 0 1 0 0 0 1 0 0 0 0 0
26.......... 1 1 1 0 0 1 1 0 0 0 0 0 1 0 0 0
27.......... 0 0 2 0 0 1 0 1 0 0 0 0 0 0 0 0
28.......... 0 0 1 1 0 1 0 1 1 0 0 0 0 0 0 0
29......... 0 0 1 0 0 2 0 2 0 1 0 0 0 0 0 0
30......... 0 1 1 0 1 0 1 0 0 0 0 0 0 0 0 0 cM
31......... 0 2 1 1 0 .... .... 0 0 0 .... .... .... ...
Totals ........ 271 93 65 98 26 57 94 109 I 45 ) 44 44 ) 56 2 0 0 0








Florida Agricultural Experiment Station


I UA
I I..., I ,.. .1 ...I I ..I .. .. l.

Fig. 17.-Chart showing the daily maximum and minimum temperatures,
rainfall, and boll weevil emergence at Gainesville, Florida, 1930, from
four hibernation cages containing a total of 23,096 weevils, located on
the ground in the woods. Clear, partly cloudy, and cloudy days are
indicated by unshaded, half shaded, and full shaded circles, respectively.
April, and May, with but a sprinkle of weevils appearing in June.
Low temperatures in March and April, however, were not at-
tended by completely checked emergence, though abrupt rises
in temperature were accompanied by the emergence of relatively
large numbers of weevils. The comparatively dry weather ex-
tending from April 26 to May 19 was not attended by checked
emergence, a slight flush appearing during the week of May 3-10.
The chart showing the appearance of the weevils in the field
(Fig. 18), is also very much like the field emergence charts pre-
viously shown. A limited emergence took place in the latter


Fig. 18.-Chart showing the daily maximum and minimum temperatures,
rainfall, and boll weevil appearance in a cotton field at Gainesville,
Florida, 1930. Clear, partly cloudy, and cloudy days are indicated by
unshaded, half shaded, and full shaded small circles, respectively.






TABLE XXI.-SUMMARY OF BOLL WEEVIL EMERGENCE FROM HIBERNATION CAGES AT GAINESVILLE, FLORIDA, 1930.
Total
March April May June July Emergence



I 0,
Cages- 27 27.0 26 26.0 45 45.0 2 2.0 0 0 100 100.0 6,000 1.67



1 ... 27 27.0 26 26.0 45 45.0 2 2.0 0 0 100 100.0 6,000 1.67


TABLE XXII.-RECORD OF THE DATES ON WHICH SPECIFIED PERCENT OF THE TOTAL NUMBER OF BOLL WEEVILS HAD
EMERGED FROM HIBERNATION CAGES AT GAINESVILLE, FLORIDA, 1930.
Dates When Boll Weevils Emerged
Cages 25 Percent 50 Percent 75 Percent 90 Percent 95 Percent | 98 Percent 100 Percent

1.......................... March 25 April 21 May 11 May 21 May 23 May 31 June 26
2 ....................... March 17 April 3 April 26 May 14 May 18 May 23 May 29
3 ....................... March 21 April 13 April 21 May 9 May 11 May 17 May 25
SMarch 18 April 12 April 21 May 9 May 12 May 17 May 23
4........................... March 18 April 12 April 21 May 9 May 12 May 17 May 23
I I I i







Florida Agricultural Experiment Station


part of May, while the majority of the weevils appeared in June,
the peak emergence taking place on June 11. As in former ex-
periments the field appearance did not begin until the hiberna-
tion cage emergence was practically completed. Temperature
changes appeared to affect boll weevil entrance into the field
somewhat and it is possible that the dry weather extending from
April 26 to May 19 limited the field appearance during that time.

SUMMARY OF HIBERNATION CAGE EXPERIMENTS
AND FIELD COUNTS, 1926-30

Figures 3, 5, 6, and 9 through 18 and Tables I through XXII,
together with the discussions of the emergence of boll weevils
from hibernation in cages and their appearance in cotton fields,
present hibernation information for the period extending from
1926 through 1930. The following tests were discussed:
Field test, 642 weevils captured, at Gainesville, Florida, 1926.
1 large cage containing 28,347 weevils at Gainesville, Florida,
1926-27.
Field test, 1,188 weevils captured, at Gainesville, Florida, 1927.
Field test, 72 weevils captured, at Thomasville, Georgia, 1927.
5 cages containing 40,000 weevils at Gainesville, Florida, 1927-
28.
Field test, 56 weevils captured, at Baker, Florida, 1928.
3 cages containing 26,000 weevils at Gainesville, Florida, 1928-
29.
Field test, 500 weevils captured, at Gainesville, Florida, 1929.
4 cages containing 23,096 weevils at Gainesville, Florida, 1929-
30.
Field test, 76 weevils captured, at Gainesville, Florida, 1930.
In considering the presented data two striking features of
the field counts of boll weevil appearance in the field are note-
worthy: First, that the appearance of emerged weevils in the
field during any one year is remarkably similar to that of each
of the other years, any appreciable appearance rarely extending
over a period lasting more than 30 days; and second, that the
field appearance of emerged weevils does not begin until the
emergence of weevils from the hibernation cages is practically
completed. Needless to say, the uniformity of the late appear-
ance of the weevils which were recorded in the field counts was
unexpected, though there can now be no doubt of the fact that
the weevil emerges from its natural winter quarters much later







Bulletin 233, Winter Survival of the Cotton Boll Weevil 39

than it has been reported to have quit its hibernation quarters
in the cage.
The uniformity of the annual pictures of the field appearance
seems to coincide remarkably with the temperature conditions
prevalent during May and June, regardless of what the weather
conditions were prior to that time. The field appearance of
weevils in 1926 (Fig. 3) and in 1927 (Fig. 6) show an initial
emergence early in May which is followed by a definite drop in
temperature, checking further emergence until, in June, a fairly
uniform minimum temperature of 600 to 65F. occurs, when
practically the total percentage of the weevils emerged from hi-
bernation and appeared in the field. Of especial interest is the
field appearance of weevils in 1927 when weevils were captured
during the relatively long stretches of warm weather occurring
during March, April, and the early part of May. It is quite pos-
sible that the weevils entering the field on these early dates left
the rather thin hibernation quarters along a bushy fence row
adjacent to the field. The later and much heavier emergence
was probably delayed by the denser hibernation material found
in the adjacent woods where the trees were heavily laden with
Spanish moss. A similar condition occurred in 1928 (Fig. 11).
That the nature of the hibernation material affects boll weevil
emergence from hibernation has been experimentally demon-
strated numerous times (2, 9, 13).
The field counts of 1928 (Fig. 11) also present a rather ex-
tended period of appearance in the field, again showing some
correlation with, though lagging somewhat behind, temperature
changes. In 1929 (Fig. 16) the field emergence shows a very
definite relationship between a mean minimum temperature of
620-670F. The peak emergence of June 3, 1929, however, re-
mains unaccountable, at least from interpretation resting on
available temperature or rainfall data. Cool weather occurring
during the early spring of 1930 (Fig. 18) is probably responsible
for the delay of emergence until the latter part of May, at which
time emergence started with warmer weather and responded to
temperature changes, with the exception of the occurrence of
the peak of appearance, June 11, which took place following the
lowest minimum temperature that was recorded after April 26.
It is possible, though, that the heavy rainfalls which had con-
tinued for two weeks prior to June 8, held the weevils back,
causing them to seek cotton fields in larger numbers after the
cessation of the rains. In four of the five years during which







Florida Agricultural Experiment Station


the field counts were made, the peak of appearance took place
after several days of dry weather following the usual heavy
June rainfalls. In the exception, 1928, the peak of appearance
fell on June 15, a partly cloudy day, during and immediately
after other days attended with heavy rainfalls.
Though hibernation cage work had been definitely discontin-
ued in 1925, the results obtained from the first field counts of
weevils appearing in a cotton field pointed out the necessity of
conducting additional hibernation cage tests concurrently with
the field tests. As a consequence cage work was again started
and series of cages were operated each year from 1926 through
1930. The information secured during this period, however, was
of the same character as that obtained from the cages used from
1922-25. From the time the weevils were placed in the cages to
the date of their removal individual weevils were active. In
the cage (Fig. 5), which was placed on the ground in the woods
in 1926-27, the period of continuous emergence was completed
shortly after the peak emergence of June 2. In the same cage in
1927-28 (Fig. 12) emergence was completed in May, a condition
probably due to faulty cage construction, while other cages (Fig.
10) on the ground in the woods at the same time and conducted
under the same conditions yielded weevils until the end of June.
In still other cages which were placed on the ground in an open
field (Fig. 9) emergence was completed in April with the ex-
ception of an isolated weevil which emerged in May. In the
1928-29 series (Figures 13, 14, and 15) the emergence was un-
usually late. Extreme care in preparing the cages for these
particular tests and the careful selection of weevils for hiberna-
tion, however, resulted in a series of cages more like each other
than any other series heretofore observed. The 1930 series (Fig.
17) shows an early and irregular type of cage emergence, a
condition probably, in this case, due to the early confinement of
weevils in the hibernation cages. All of the hibernation cage
tests fail to show a seasonal uniformity under the same weather
conditions encountered by the field tests which, in turn, did show
a very uniform emergence rate and limited range of time during
which weevils quit hibernation.
The effect of minimum temperature changes on the emergence
rate of the weevils in hibernation cages appeared to substantiate
the results obtained during the 1922-25 tests, namely, that a
drop of the minimum below 550F. was accompanied by a retard-







Bulletin 233, Winter Survival of the Cotton Boll Weevil 41

ation of the emergence. On the other hand, rapid rises above
550F. appeared to be accompanied by accelerated emergence.
Careful analysis of the seasonal rainfall failed to yield data
which indicated a positive correlation between rainfall and boll
weevil emergence. The weevils seem to delay their emergence,
however, until the cessation of heavy rainfall. As in the series
of 1922-25, emergence on clear, partly cloudy, and cloudy days,
respectively, showed no characteristic correlation. Since, how-
ever, there were more partly cloudy days under observation than
cloudy or clear ones the majority of the weevils emerged on
partly cloudy days.

COMPARISON OF EMERGENCE FROM HIBERNATION
CAGES WITH FIELD COUNTS

A comparison of the peak of appearance of the weevil in the
field with that in the cage emergence counts, presented in Tables
XXIII and XXIV, respectively, shows that the peaks in the
field counts extended from June 3 to June 20, while in the cage
counts the peaks extended from March 5 to June 2. The per-
cents of the total emergence of weevils recorded on the peak
days range from 13.5 percent to 24.0 percent in the field counts
and from 3.28 percent to 7.89 percent in the cage tests. Com-
paring the field average, 19.02 percent, with that of the cage
average, 5.72 percent, the former shows over three times as
great an emergence on peak days as the latter. Since weevils
were captured in the field only three times a week, however,
while they were captured daily in the cages, this particular com-
parison is not very significant. On the other hand, the fact
that the extent of the peak emergence periods for the field
counts cover a much narrower range than those for the cage
experiments is significant. The total period of weevil appear-
ance in the field counts is also much shorter than that of the
hibernation cages.
TABLE XXIII.-PEAKS OF APPEARANCE OF WEEVILS AS FOUND IN FIELD
COUNTS AT GAINESVILLE, FLORIDA, DURING THE FIVE-YEAR PERIOD, 1926-
1930.
SNumber Total number Percent of total
Year Date of peak weevils on for season on peak day
peak day
1926 June 20 87 642 13.5
1927 June 13 286 1,188 24.0
1928 June 15 67 393 17.0
1929 June 3 117 500 23.4
1930 June 11 13 76 17.2







Florida Agricultural Experiment Station


TABLE XXIV.-PEAKS OF EMERGENCE OCCURRING IN HIBERNATION CAGES AT
GAINESVILLE, FLORIDA, DURING THE FOUR-YEAR PERIOD, 1927-1930.


Number Total num- Percent of
Year Cage Date weevils on her for total on
Number of peak peak day season peak day


1927 1 June 2 145 3,615 4.01
1928 1 March 11 28 487 5.75
2, 3 March 5 27 824 3.28
4, 5 March 9 6 78 7.69
1929 1 May 6 329 5,765 5.71
2 May 21 37 876 4.22
3 April 8 55 762 7.22
1930 1-4 March 18 60 760 7.89


In addition to the consideration of the peak of appearance
dates, another basis for making a comparison of the appear-
ance of the weevil from hibernation in the field with the emerg-
ence found in cages is one by which an examination of the total
emergences is considered. Table XXV and Fig. 1 are compiled
from data accruing from cage and field tests operated concur-
rently for four consecutive years. During this time 2,157
weevils were captured in the field and 117,443 weevils were plac-
ed in hibernation cages; of this latter number 13,167 weevils
emerged from hibernation. The percent tabulated in Table
XXV were obtained by first calculating the percent emergence
obtained for each day in each of the cages employed during the
four annual tests. These percent were then added and an av-
erage percent for the daily emergence was calculated by dividing
the sum by the number of cages used. These daily averages
were then added to represent weekly periods. The field-emerg-
ence percent was obtained in the same way. The weekly periods
are presented in Figure 1, the shaded blocks representing the
weekly percent of the total number (13,167, or 100 percent) of
weevils emerging from the cages, and the solid blocks represent-
ing the weekly percent of the total number (2,157, or 100 per-
cent) of weevils appearing in the field. Though many more
weevils are represented by the shaded blocks than by the solid
blocks, the presentation of the comparative times of emergence
in this instance is not affected by the weevil number, since suf-
ficient samples were employed in constructing the chart on a
percentage basis.







Bulletin 233, Winter Survival of the Cotton Boll Weevil 43

TABLE XXV.-THE AVERAGE PERCENT OF BOLL WEEVILS EMERGING FROM HI-
BERNATION FOR A PERIOD OF FOUR YEARS, 1926-30, IN THE FIELD COUNTS
AND IN HIBERNATION CAGE TESTS AT GAINESVILLE, FLORIDA.
Percent weevils captured
Week endingField Cage
Field Cages

March 6...................... 0 12.51*
13 ............. ... 0 7.52
20 .................... 0.19 8.89
27 ..................... 0.04 5.47
April 3 ...........-......... 0.02 5.54
10 .... .............. 0.02 8.43
17...................... 0 8.29
24 ..................... 0.13 7.04
May 1........ .... 0.81 3.63
8 ..... ...- 0.80 8.22
15 .....................- 1.79 5.83
22 ................ 2.33 5.37
29 ....................I. 6.05 3.05
June 5....... ... ..... 16.60 4.31
12....................u 21.33 1.76
19 ...............- ... 31.54 1.78
26 .......... ......... 14.45 0.82
July 3 ................. 3.78 0.98
After July 3....-................ 0** 0.73***

*This week includes all of the weevils which were caught on the first
day that cage counts were made. The majority of the weevils had been
out of hibernation for at least several days prior to the initial count.
**Field counts were discontinued after July 1, since but few additional
hibernated weevils appeared while numerous field hatched weevils infested
the field.
***The week ending July 10 yielded 0.30 percent; July 17, 0.16 percent;
July 24, 0.16 percent; July 31, 0.09 percent and August 7, 0.02 percent
emergence, respectively. Seven additional isolated weevils emerged from
the cages.

The uniformity of the weekly periods of the hibernation cage
emergence which gradually decreases in percent emergence is
noteworthy and presents an entirely different picture from the
one shown by the field appearance which rises rapidly to a peak
and then drops with even greater rapidity. The most significant
point illustrated is the fact that the field appearance of weevils
emerging from hibernation does not start until the cage emerg-
ence is well spent. The conventional interpretation of the data
presented in Fig. 1 would indicate either that the biological
characteristics of the weevils emerging from hibernation in the
cage were different from those of the weevils appearing in the
field, or that the nature of the hibernation quarters effect a dif-
ferent weevil response. Explanation of the data based on the
supposition that annual changes in the weevil's environments






Florida Agricultural Experiment Station


could effect an immediate change in the innate characteristics
of the weevil is, from a biological standpoint, irrelevant, if not
actually misleading. Likewise, the assumption that the dif-
fering natures of the hibernation quarters could effect so great
a change in weevil emergence as that occurring between the cage
and field tests, also considered from a biological viewpoint, is
invalid.
Based on the assumption, however, that the biology or physi-
ological condition of the weevil, depending on whether it hiber-
nates in cages or in the field, does not change abruptly, the aris-
ing differences in the hibernation records must be ascribed to
the experimental methods employed in collecting the hibernation
data. Consequently, the fact that the field appearance of weevils
emerging from hibernation does not begin until the emergence
of weevils from the hibernation cages is practically completed,
can be accounted for by showing that hibernation cage work
has long been based on faulty assumptions. When the data
which are secured from hibernation cage emergence are in-
terpreted there appears to be a tacit assumption to the effect
that, regardless of the time when the weevils are removed from
the cage and recorded, they would live as long as the last weevil
to be removed from the cage lived. In other words, when emerg-
ed boll weevils are removed from hibernation cages in March,
they are recorded and removed from the experiment, likewise
with the weevils removed in April and May. And furthermore
the emergence data for each month are considered on a par with
those of each other month. Were the weevils allowed to remain
in the cage, many of them would die before the cage experiment
was concluded, and so the percent of emergence during March,
April, May, and June would vary considerably from the data
recorded on the assumption that the weevils emerging in March
have the same numerical value as those emerging in June. The
statistical difficulties involved when experimental units are re-
moved from the test are considerable, unless the ultimate in-
formation desired is merely that of a limited comparative nature
-not comparative from year to year but from month to month
in any one year.
Another assumption that renders difficult a correct interpre-
tation of the data which were secured from hibernation cage
emergence is one by which it is held that when the weevil
emerges from hibernation in the cage it has completed its winter
rest. The invalidity of this assumption was proved experiment-






Bulletin 233, Winter Survival of the Cotton Boll Weevil 45

ally when hibernation cage experimentation conducted at Dallas,
Texas, in 1906, indicated that one weevil emerged from and re-
entered hibernation as many as eight times during a period ex-
tending from October, 1905, to May, 1906 (11). A large number
of weevils were observed to leave their winter quarters and sub-
sequently reenter hibernation. The work stopped with this in-
formation, but by analogy it can be assumed that boll weevils
act in the same manner in their natural hibernation quarters
in the woods and fields, completing their final emergence from
hibernation and starting their search for a cotton field in May
and June. Were boll weevils allowed to remain in the hiberna-
tion cage until they appeared to have fully completed their hi-
bernation period, the resulting tabulation of hibernation cage
data would, in all probability, be very similar to that of the
field count data presented in this bulletin.
As a consequence of the general acceptance of these two false
assumptions, one is led to accept a seeming biological discrep-
ancy existing between the field and cage emergence from hiber-
nation herewith presented. The fact that hibernation cage data
is still misconstrued, however, continues to face investigators
interested in the boll weevil, and so when hibernation cages are
used to secure information concerning the winter survival of boll
weevils and their probable abundance, the data which are se-
cured from cages are often misleading. Field counts, on the
other hand, indicate definitely what intensity of boll weevil sur-
vival and infestation may be expected.

SUMMARY AND CONCLUSIONS

Hibernation cage tests beginning in 1926 and continuing
through 1930 included 117,443 weevils. The data which were
secured were characteristically inconsistent relative to the per-
cent survival and time of emergence. The survival in individual
cages varied from 0.8 percent to 34.2 percent. The time of
emergence extended from February 28 to September 7, while
the peak emergences extended from March 5 to June 2. Hiber-
nation cage data, therefore, could not be used for forecasting
the probable boll weevil population. All of the hibernation
cage tests failed to show a seasonal uniformity of emergence
under the same weather conditions encountered by the field tests,
which, in turn, did show a very uniform emergence rate and
limited range of time during which weevils quit hibernation.






Florida Agricultural Experiment Station


Field counts in which all of the weevils which left their hi-
bernation quarters and entered a selected cotton field during
the spring and early summer were begun in 1926, and continued
through 1930, during which time 2,157 weevils were captured.
The data which were secured were uniform, each year's results
corresponding with those of the following or preceding years.
Field counts which were conducted in five widely separated lo-
cations in Florida yielded uniform results. The time of appear-
ance of the weevils in the field rarely extended over a period of
30 days, while the emergence period in hibernation cages ex-
tended over a period of five months. The peak of appearance
in the field extended from June 3-20, while in the cage counts
the peak emergences extended from March 5 to June 2.
The field appearance of weevils does not begin until the cage
emergence is practically completed.
The field appearance of weevils seems to be dependent upon
the temperature conditions prevalent during May and June (the
cotton plants also show the same relationship), regardless of the
nature of the weather conditions prior to that time.
Weevils which had just emerged from their hibernation quar-
ters were marked and liberated in the woods near the experi-
mental fields. About 10 percent were recovered within two
days. The remainder of the marked weevils were not recovered.
It follows, then, that field counts of weevils appearing in the field
probably indicate the approximate time of their emergence from
their natural hibernation quarters.
The data which are secured from hibernation cages are mis-
leading when interpreted in the light of determining a popula-
tion forecast. This fact is probably the result of the acceptance
of two assumptions on which the interpretation of the data has
rested. The first assumption is one in which it is thought that
when weevils emerge from hibernation in a cage they can be
removed from the cage and recorded regardless of the fact that
many individuals would reenter hibernation. The second assump-
tion indicates that the weevils which are removed from the cages
during the earlier months would live as long as the weevils which
were removed at the end of the hibernation cage counts.
The data which are secured from field counts, however, in-
dicate what intensity of boll weevil survival and field infesta-
tion can be expected from year to year.
The experimental evidence which was obtained during five
consecutive years indicated that boll weevils enter cotton fields







Bulletin 238, Winter Survival of the Cotton Boll Weevil 47

in infested areas in Florida daily during the month of June.
With this definite information relative to the emergence of the
weevil from its natural hibernation quarters and its subsequent
appearance in the field, a timely and effective program for pois-
oning the boll weevil can be planned easily.

LITERATURE CITED

1. FENTON, F. A. and E. W. DUNNAM. Winter survival of the cotton boll
weevil at Florence, S. C. Jour. Econ. Ent. 20:327-336. 1927.
2. ................................. Biology of the cotton boll weevil at Florence, S. C.
U. S. D. A. Tec. Bul. 112:55-65. 1929.
3. GROSSMAN, EDGAR F. Fla. Agr. Exp. Sta. Ann. Rpt. 1926. p. 40.
4. ............................... Fla. Agr. Exp. Sta. Ann. Rpt. 1927. pp. 41-42.
5. ................................. Fla. Agr. Exp. Sta. Ann. Rpt. 1928. pp. 40-41.
6. ................................. Longevity records of the cotton boll weevil. The
Fla. Ent. 12:57-59. 1928.
7. ................................. Resumption of egg-laying by hibernated cotton boll
weevils. The Fla. Ent. 12:33-38. 1928.
8. ................................ Fla. Agr. Exp. Sta. Ann. Rpt. 1929. p. 50.
9. HINDS, W. E., and W. W. YOTHERS. Hibernation of the Mexican cot-
ton boll weevil. U. S. D. A. Bur. Ent. Bul. 77:1-106. 1909.
10. HUNTER, W. D., and W. E. HINDS. The Mexican cotton boll weevil.
U. S. D. A. Div. Ent. Bul. 45:82-92. 1904.
11. ................................. The Mexican cotton boll weevil. U. S. D. A. Bur.
Ent. Bul. 51:103-121. 1905.
12. HUNTER, W. D., and W. D. PIERCE. The Mexican cotton boll weevil: A
summary of the results of the investigation of this insect up to Dec.
31, 1911. U. S. D. A. Bur. Ent. Bul. 114:95-116. 1912.
13. NEWELL, WILMON, and M. S. DOUGHERTY. The hibernation of the cotton
boll weevil in central Louisiana. State Crop Pest Comm. La. Cir.
31:163-219. 1909.
14. S. C. Exp. Sta. Thirty-eighth annual report: 10-13. 1925.




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