?She

Florida Entomologist
Official Organ of the Florida Entomological Society

Vol. XIV WINTER NUMBER No. 4
DECEMBER, 1930

TIBICEN DAVISI Smith and Gosbeck (CICADIDAE) A NEW
PEST OF ECONOMIC IMPORTANCE*
By J. W. WILSON
In the September issue of THE FLORIDA ENTOMOLOGIST there
appeared an article describing the attack of cicadas upon As-
paragus plumosus. Since that time we have been able to collect
further data on the cicada which is responsible for this damage
and it seemed advisable to present this data at this time.
As early as June 27th when the first visit was made to
Jupiter large numbers of a small species of cicada Diceroprocta
olympusa Walker were present in the pine trees and bushes of
that vicinity. It was an easy task to capture many males, and
a few females were captured. The males are easily located
by their loud continuous, monotonous, and unvarying song. A
few specimens of this species have been observed and captured
in the ferneryy", and a few cast nymphal skins have also been
collected in the ferneryy". On July 10th (the second visit to
Jupiter), a different type of cicada song was heard and on
August 11th females of this species were observed laying eggs
in dead sea oats stems about 100 feet from the beach. Mr. Wm.
T. Davis identified this species as Diceroprocta viridifacia
Walker. None of the adults of this species were observed in the
"ferneries" throughout the summer, although there appears
to be no reason why this species should not feed on Asparagus
plumosus. On September 15th the females of this species had
disappeared but a few males were heard singing in the brush
near by. On August 1st still another cicada song was heard
but males of this species were not captured until August 7th.
Upon examination Mr. Davis determined that these specimens
belonged to the species Tibicen davisi Smith and Grosbeck. As
*Contribution from the Department of Entomology, Florida Agricul-
tural Experiment Station.

THE FLORIDA ENTOMOLOGIST

the season advanced more and more individuals of this species
emerged from the fernery each day.
Until September 8th very few females of T. davisi were ob-
served emerging. On August 30th 100 cast nymphal cases were
collected; only five of these were shed by females. After Sep-
tember 8, large numbers of both sexes emerged each day. The
peak of the daily emergence came between September 16th and
30th, but individuals continued to emerge until October 15th.
Since the publication of the article in September cast nymphal
skins, which were of a size that indicated that they were T.
davisi have been collected in "ferneries" at Yalaha, Melbourne,
and Boynton. Males of this species were captured in the woods
at Pierson, and several growers from various sections of the
state report that a few cicada cases have been observed in their
"ferneries". But it is only at Jupiter that they have become
abundant enough to do noticeable damage.
A large number of males and females were collected and
placed in screen cages over Asparagus plumosus, but in every
case all the specimens died within forty-eight hours. For this
reason it has been impossible up to the present to collect data
on the time of mating, the length of the preoviposition period,
and the length of adult life. Dr. R. H. Beamer working with
several species of cicada in Kansas found however, that the
adult can be kept alive in cages for long periods of time if the
proper food plant is supplied. It seems surprising that the adults
of this species do not feed on A. plumosus for the young shoots
are very tender and succulent. Thinking that my first cage was
too small I built a much larger one and placed it over plants
with mature nymphs on the roots, but all of the adults which
emerged in this cage also died within forty-eight hours. I have
not yet observed adults feeding on A. plumosus. It seems evi-
dent that the adults leave the fernery to feed and mate and
the females return to deposit their eggs.
The full grown nymphal cicadas begin emerging from the
ground very early in the evening. They crawl upon the near-
est support and in many cases travel as much as twenty-five
feet before stopping to shed the nymphal case. By ten o'clock
many of the adults have already completed the task of shedding
the last nymphal skin and may be observed clinging to the
plants and supports of the sheds expanding their wings and
drying themselves. At sunrise most of the individuals are
ready for flight, but very few of them begin flying before about
eight o'clock.

WINTER NUMBER

The females will deposit their eggs in almost any kind of
plant material which they find available. Comparatively few
of the eggs are placed in the stems of A. plumosus. The fe-
males distinctly prefer the dried and seasoned timbers, of which
the sheds are constructed, to any other available material. It
seems to make little difference whether this material is pine
or cypress. The eggs are placed in holes drilled by the stout
ovipositor of the female. A series of as many as twenty-five
to thirty of these nests will be placed in a row if the laying
female is not disturbed. From five to twelve eggs are placed in
a single row in each of these nests. The nest may be sealed
with a frothy secretion but in most cases it is not sealed in any
way. Eggs deposited as early as September 8th have not yet
hatched out (November 13th), so it is assumed that this species
passes the winter in the egg stage. Beamer reports that many
of the cicada belonging to the genus Tibicen pass the winter
in the egg stage in Kansas.
When the young nymphs hatch out they will be about the
same length as the egg which is 2.3 mm. in length. These
small nymphs will make their way to the opening of the nest
and after casting what Beamer designates as the postnatal skin,
they will cast themselves bodily into space. They will im-
mediately make their way to the roots of the plant, form a cell
and begin feeding. In June only a few third stage nymphs
were found in spite of the fact that most of the soil dug was
run through a small meshed screen. Large numbers of fourth
stage nymphs and early fifth stage nymphs were collected at
this time. The nymphs are usually found about six inches
below the surface of the soil directly beneath the crown of
the plant. They are never found on A. plumosus deeper than
eight inches for this is the maximum depth at which this plant
produces numbers of roots or crowns. In August, and Septem-
ber, many full grown fifth stage nymphs and some fourth
stage nymphs were collected. The full grown fifth stage
nymph is recognized by its increased size and the prominent,
red eyes. It is assumed that these fourth stage nymphs either
pass the winter as such or transform to fifth stage nymphs
and pass the winter in this stage.
We have not been working on this problem long enough to
assign any definite length of time for the development of any
of the immature stages. Any statement as to the length of
time required for the development is mere conjecture but evi-

THE FLORIDA ENTOMOLOGIST

dence seems to indicate that this species does not require longer
than three or four years.
During the summer nearly every available insecticide was
used in an attempt to control the nymphs in the soil. These
included various strengths of calcium cyanide, Black Leaf 40,
carbolic acid emulsion, a number of pyrethrum compounds,
chloride of lime, kerosene emulsion, Mowrah Meal (a fertilizer
somewhat like castor pummace), steam, hot water, carbon di-
sulphide, and carbon disulphide emulsion. Of these carbon
disulphide emulsion alone was effective to any extent. The
emulsion was made up by a 1-3-10 formula, 1 part fish oil soap,
3 parts water, 10 parts carbon disulphide. This emulsion was
then diluted at the rate of one pint to twelve gallons of water.
Three pints of this dilute solution was applied to each square
foot of soil. This treatment gave a good control for the fourth
stage nymphs, but did not have any noticeable effect upon the
fifth stage nymphs. If this material is made stronger either
by adding more of the concentrated emulsion to the water or
by applying more of the solution to each square foot of soil, the
plants will die. This treatment will cost about $160.00 per
acre for each application.
A very ingenious method of control was used very effectively
by Mr. Wilkinson, the grower whose "ferns" were most severely
'damaged this summer. This control should properly be called
the Hydraulic Pressure Method. It consists merely of attach-
ing a garden hose at convenient points to the irrigation system
and stopping all other openings of the system. A one-quarter
inch pipe about three feet long is attached to the end of the
hose. By this means he obtained about eighty pounds pressure
at the nozzle end. The stream of water is directed into the
soil holding the end of the nozzle about two inches from the
soil. This stream of water thoroughly cultivates every inch
of the soil and penetrates to a depth of about twelve inches or
deeper, depending on how long the nozzle is held in one place.
Large numbers of the nymphs are rolled out upon the surface
and left to dry out and die. Many are hit directly by the
stream and torn to pieces. A few of the larger nymphs escape
unharmed but all of these emerged as adults in September.
Thus in October when we went over a plot of about seventy-
five square feet for the second time, it was found that his
ferneryy" was practically free of the nymphs and will remain
free until the next brood of eggs hatches out. Mr. Wilkinson
estimates that this treatment will cost about $40 per acre, or

WINTER NUMBER

about one-fourth as much as the carbon disulphate emulsion
treatment. This treatment has other advantages. By this
means the grower is enabled to cultivate the soil which has
been impossible heretofore because of the 'nature of growing
A. plumosus. Fertilizers can be applied to the top of the soil
as has been the practice and washed into the soil. Most of the
smaller weeds are destroyed by this means. Mr. Wilkinson
also thinks that the treatment noticeably reduced the numbers
of the developing brood of noctuidae by destroying many of
the pupae in the soil.
In September a number of materials were applied to the
shed in an attempt to prevent the females depositing their
eggs in the timbers of the ferneryy". Bordeaux mixture, vari-
ous strengths of oil emulsion, lime-sulphur solution, and white-
wash were used. Of these the plot upon which whitewash was
used was the only one avoided by the females. This was only
a small plot and might not prove effective if the whole shed
were treated. The whitewash also vastly increases the amount
of light in the ferneryy", and if used on a large scale lamp black
should be mixed with it.
A little later on various strengths of oil emulsions, carbon
disulphide and carbon disulphide emulsion, lime-sulphur, and
paridichlorobenzene were applied to egg nests. Since none
of the eggs have yet hatched it is not possible to determine
how effective these treatments will be.
I have not yet collected any egg parasites or nymphal para-
sites but Beamer reports that there is a large number of both
egg and nymphal parasites which attack the Kansas Cicadidae.
No doubt some of these also attack Tibicen davisi and other
Cicadidae found in Florida. A large species of Robber Fly has
been observed feeding upon the adult cicadas, but the Robber
Fly escaped before I could capture it for identification. A
large species of Spider which builds its web in the ferneryy"
has also been observed feeding upon the adults. A great many
of the adults are destroyed by mocking birds, blue jays, and
mourning doves. Large flocks of these birds congregate around
the ferneries during the period when the adults are emerging.
One grower attributed the excessive numbers of cicadas in 1930
to a direct affect of the 1928 hurricane which killed many birds
in that region. Skunks, field rats and moles dig up and eat
some of the nymphal cicadas but we have no way of determin-
ing how many these predators destroy.

Uhe
FLORIDA ENTOMOLOGIST
Official Organ of The Florida Entomological Society, Gainesville,
Florida.

Vol. XIV, No. 4 December, 1930

J. R. W ATSON.....--.....................................................................Editor
WILMON NEWELL .......................................--- .........Associate Editor
A. N. TISSOT ..-...........---- ...-------- ................ ... ---- Business Manager
Issued once every three months. Free to all members of the
Society.
Subscription price to non-members is $1.00 per year in ad-
vance; 35 cents per copy.

BIOLOGY OF THE MEXICAN COTTON BOLL WEEVIL. VI.
Some Humidity and Temperature Effects on
Development and Longevity'
By EDGAR F. GROSSMAN
The difficulty encountered in keeping cotton boll weevils
(Anthonomus grandis Boh.) alive in low temperature incu-
bators equipped with brine coils led to the determination of
the optimum range of relative humidity necessary for success-
.ful weevil hibernation in artificially cooled environments. In
order to secure and maintain a number of constant relative
humidities, 200 cc. of varying percent of sulphuric acid and
distilled water were placed in desiccators measuring seven
inches in diameter. The sulphuric acid solutions were mixed
in accordance with data presented by R. E. Wilson.
The specific gravity of each solution was then recorded and
subsequent determinations of the relative humidity of each
desiccator were obtained by specific gravity measurements.
Though the majority of the solutions remained constant, some
of them, after being used for a month, varied by one half of one
percent relative humidity. Allowances for temperature correc-
tions were not made since the percent relative humidity varied
but slightly between 210 C. and 270 C., and the series in which
the temperatures were maintained at 150 C. and 20 C., respec-
tively, showed no critical points of interest. Daily aeration of
1Contribution from the Department of Cotton Investigations, Florida
Agricultural Experiment Stations.
"Wilson, Robert E. "Humidity Control by Means of Sulphuric Acid So-
lutions." Jour. Indus. and Engin. Chem. Vol. XIII, No. 4. pp. 326-29. 1921.

WINTER NUMBER

the desiccators eliminated the accumulative carbon dioxide gen-
erated by the insects, without noticeably changing the concen-
tration of the sulfuric acid solutions. The following solutions
were used:

Specific Gravity
1.000
1.039
1.080
1.124
1.163
1.202
1.243
1.286
1.321
1.366
1.405
1.435
1.477
1.520
1.565
1.599
1.646
1.681
1.716

Percent Sulfuric
Acid
.00
6.00
12.00
18.00
23.00
28.00
33.00
38.00
42.00
47.00
51.00
54.00
58.00
62.00
66.00
69.00
73.00
76.00
79.00

Approximate Relative
Humidity
100
98
95
90
85
79
70
61
53
43
35
29
21
14
9
6
3
2
1

Boll weevils freshly captured in a nearby cotton field were
confined in small galvanized iron wire mesh cages to avoid the
possibility of having the weevils fall into the sulfuric acid solu-
tions. The cages were then placed in nineteen desiccators which
were maintained at the specified relative humidities. The infor-
mation presented in Table I is self-explanatory, the optimum
range extending from 61 percent to 98 percent relative humidity
for 27 C.; from 21 percent to 100 percent for 150 C.; and from
9 percent to 100 percent for 20 C. A decrease in temperature
apparently minimizes the lethal effect which a low percent hu-
midity exercises on adult boll weevils, whereas increased tem-
peratures tend to narrow the range of optimum relative humid-
ity.
Additional experiments were conducted with adult weevils in
order to determine, by examination of the desiccators at two-
day intervals, the longevity of weevils maintained at 270 C. over
a range extending from 6 percent to 100 percent relative humid-
ity, and also at 210 C. over a range extending from 1 percent to
100 percent relative humidity. Two sets of desiccators were

THE FLORIDA ENTOMOLOGIST

used for each temperature experiment, fresh cotton squares be-
ing supplied the weevils in one set and no food at all being sup-
plied the weevils in the other set. A study of Tables II and III
shows that, with the possible exception of relative humidities
below 35 percent, both at 270 C. and 21 C., respectively, the
presence of food increased the period of time through which
adult weevils live. As in Table I, a decrease in temperature is
accompanied by a widening of the range of the relative humidi-
ties which are non-lethal to the adult. An additional factor is
the longevity records of weevils confined in desiccators main-
tained at 210 C., where a large number of weevils lived longest
between 79 percent and 98 percent relative humidity, one weevil
living over 161 days at 95 percent relative humidity. A large
number of weevils confined at 130 C. with a range of relative
humidity extending from 70 percent to 85 percent lived over 300
days, one weevil living 359 days under such conditions. When
the relative humidity was maintained at 60 percent or less,
weevils did not live so long, dying rapidly when 35 percent or
less was reached.
In order to determine the range of optimum percent of
relative humidity required for boll weevil transformation, fresh
cotton squares into which boll weevils had oviposited were placed
..into desiccators daily. The egg-laden squares were kept at 21
C. and 27 C., respectively, the range of relative humidity ex-
tending from 1 percent to 100 percent in each of the two tem-
peratures. The effect of the various relative humidities was
more marked on the weevil transformation than on the adults.
At 27 C. the range of non-lethal humidities was definitely re-
stricted to limits extending from 21 percent to 95 percent rela-
tive humidity. At 210 C. the range widened. Though the boll
weevil eggs developed into adults in a relative humidity as low
as 21 percent and as high as 95 percent, the most rapid develop-
ment at 270 C. took place at 79 percent and 85 percent relative
humidity. (See Table IV.) Other tests conducted at the same
temperature yielded similar results.
Again, when the temperature is kept constant at 21' C., the
most rapid transformation takes place at 79 percent and 85 per-
cent relative humidity. (See Table V.) A noticeable break oc-
curs when the humidity drops below 21 percent, though several
weevils managed to escape from the squares at 1, 3 and 6 per-
cents, respectively. A large number of live weevils remained in
the hardened, dry squares at 210 C., while none were found in

WINTER NUMBER

the series kept at 270 C. Both series, however, yielded but few

live pupae and relatively few live larvae.

Boll weevil transformation at 270 C. is completed in an aver-

age of 12 days when the relative humidity is kept within a 70

percent to 90 percent limit. Above or below this range the trans-

formation is retarded. At 21 C. the transformation is com-

pleted in an average of 21 days ih the same range, higher or

lower percent relative humidity retarding the transformation.

For a period extending over several days adult weevils can

withstand any percent relative humidity between 1 percent and

100 percent, though an optimum range limited to 61 percent low

and 98 percent high is necessary for continued activity.

TABLE I.-Percent Adult Boll Weevils Surviving Confinement in Desiccators in Which Various
Constant Temperatures and Humidities Were Maintained.

'0 Q

0 r

o1 oaz a ia a

96.00 83.33 66.67 60.00
92.00 56.67 6667 50.00

60.00 63.33 96.67 31.03
76.00 80.00 46.67 71.43

80.00 70.00 26.67 62.50
72.00 70.00 53.3 43.75
Sto Cflio 5 0 co 0o f

96.00 66.67 70.00 23.80
92.00 66.67 6643.33 60.00
60.00 63.3 96.67 31 .03
76.00 8 0.00 46.6700 1.4
80.00 70.00 26.67 62.50

72.00 70.00 33.3375

76.00 66.67 2670.0067 123.80
100.00 66.67 43.33 69.23

76.00 66.67 3.33 40 25.00
6.00 23.33 30.00 11.11
36.00 10.00 13.3367 37.0
28.00 23.33 40.0033.33
40.00 1030 233.33 12.
32.00 13.33 40.00 25.00
4.00 23.33 20.00 0
52.00 10.00 13.3 0

44.00 23.33 33.33 0
28.00 10.00 33.33 0
36.00 13.33 20.00 50.00

0
o -m

Cd 00 a

95 43.33

85 66.67
79 23.33
70 43.33
s -

53 43.33
43 40.00
35 06
29 3.33

21 20.00
14 3.33
70 04
6 43.33

3 0
2 20.00
1 13.33

0 C
. .

0
C
13

0-

o
0

0
33.33
0
0

0
0

0
0
0
0
0
0
0
0
0
0

0
0
0

a ao

00
C-COus C-10

60.00 40.00
66.67 33.33
60.00 40.00
40.00 40.00

46.67 40.00
33.33 46.67
33.33 46.67
33.33 26.67

33.33 20.00
0 13.33
0 20.00
13.33 13:33

26.67 20.00
0 13.33
13.33 0
6.67 0

0 6.67
6.67 0
0 0

a0
C3

86.67
60.00
66.67
93.33

73.33
40.00
86.67
66.67

20.00
26.67
0
33.33
46.67
0
0
20.00

0
33.33
20.00

a

o3

70.00
33.33
30.00

33.00
46 67
33.33
30.00

10.00
23.33
0
0

0
0
0
0

0
0
0

(8

00
oI C

95.00
85.00
77.50
47.50

67.50
47.50
35.00
35.00

2.50
5.00
2.50
0

0
0
0
S0

S0
0
I 0

0 > 0 >
+4 .0 a- .0

00 00
-NCO CO .- -

63.33 60.00
53.33 93.33
76.67 93.33
53.33 100.00

70.00 86.67
70.00 86.67
70.00 73.33
60.00 86.67

40.00 66.67
46.67 53.33
40.00 53.33
20.00 73.33

13.33 60.00
10.00 60.00
13.33 46.67
0 53.33

0 60.00
3.33 33.33
0 60.00

1

70 THE FLORIDA ENTOMOLOGIST

TABLE II.-Longevity of Adult Boll Weevils Confined in Desiccators Maintained at 270 C.
and Varying in Relative Humidity from 6 to 100 Percent. Fifty Weevils were Placed
in Each Desiccattor, the Number Living Being Recorded at Two Day Intervals.

Food Supplied Weevils

Number Days

18 15 17

9J 4

19 21 23 25 271 29

3 21 0

lNo Food Supplied Weevils

Number Days

1 3 5 7 9 11 13

13 5 1 0
10 0
36 16 4 0
38 4 2 0

39 12 5 0
48 18 6 1 0
33 15 1 0
45 13 0

40 8 0
29 1 0
4 0
19 0

11 0
2 0
6 0
2 0

TABLE III.-Longevity of Adult Boll Weevils Confined in Desiccators Maintained at 210 C.
and Varying in Relative Humidity from 6 to 100 Percent. Fifty Weevils were Placed
in Each Desiccator, the Number Living Being Recorded at Stated Intervals.

Approxi-
mate
Relative
Humidity 4 31

100 39 17
98 48 28
95 50 26
90 46 12

85 36 15
79 39 16

61 45 11

53 35 5
43 35 3
35 39 1
29 32 0

21 33 0
14 31 0
9 24 0
6 ................... ...

3 ................ .....
2 1 0
1 23 0

Food Supplied Weevils

Number

5
21
19

9
14
4
1

0

.............
................

................

I ~~~....

No Food Supplied Weevils

r Days I Number Days

55 83 161 5 31 46

2 0 -------- - -- -- 1-- ----- ...... ---::::
17 3 0 ......... ................ ................
15 8 1 .- ..
4 1 0
6 1 0 .............. .. ......... .. ........

6 1 0 .. ...... ..... .... .....
.12 3 0 .. ........ ......... ............ .. ...

S44
.............. ............ ... .......... ... 38 4 0

...... .... ..I ...... ...... 40 0 .............
.. .-...- -........ ................... ............

.......... ............... ... ..........------------ 50 0 ................
---- .... .......... ................ 41 0 ......

....... ........ 48 0 ....
............. ... .......... ...... .......... 41 0 ....
.... --....... . . ............ -- ------ ----- ---- --------- .................

3 5 7

19 19
39 28
29 20
31 25

!aS

100
98
95
90

85
79
70
61

53
43
35
29

21
14
9
6

9 11

16 14
15 8
13 7
19 12

28 24
22
7
28

31
14
8
25

30

-- -

-~----~---

,

WINTER NUMBER 71

TABLE IV.-Boll Weevils Hatching from Eggs Laid in Fresh Cotton Squares Maintained at
270 C. but Subjected to Various Percents Relative Humidity.

SNumber Weevils Hatched and Number Additional Forms
SNumber of Days Required Found

0 e Days Adults Pupae Larvae

ZM 11 12 13 14 1 16 17 18 .

100 17 ........ ....... ........ ....... ........ ........ .....0 0 0 0 17
98 19 0 0 0 0 0 19
95 21 ........ 3 .... ........ ........ ....... ........ 0 0 0 0 0 18
90 21 ............ 3 1 ........ ....... 0 0 0 1 0 16
85 20 1 1 3 ....... ........ --- ....... 0 0 0 0 0 15
79 19 1 5 1 ............... ........ ........ 0 0 0 1 0 11
70 23 ........ 5 1 ........ 1 ... ..... ...... 0 0 0 0 0 16
61 22 ................ 2 ... ........ ........ .... 0 0 2 0 0 18
53 21 .... 1 ...... 3 .................... 0 0 0 0 13
43 21 --- ....... ........ ......... 2 0 1 0 0 2 16
85 19 .... 2 ....... ........ ....... 0 0 0 0 8 14

21 87 ....... .... 3 0 8 0 0 11 20
14 22 ........ ............................... |........ ... ........ 0 4 0 0 2 16
9 23 .--. . ...... - ....-- ........ ........ 0 0 0 0 2 21
6 26 .. .. ... ... .. .... ... ...0.. 0 2 0 0 0 24
3 29 ... ....... ........ ........ ........ 0 5 0 0 4 20
2 19 .... 0 0 0 0 19
1 25 ..... ... ........... .. .... ... 0 0 00 0 25

TABLE V.-Boll Weevils Hatching from Eggs Laid in Fresh Cotton Squares Maintained at
210 C., tut Subjected to Various Percents Relative Humidity.

o Number Additional
SNumber Weevils Hatched and Number of Days Forms Found
Required Adults iPupae Larvae

00 19 20 21 22 23 24 25 26 27 28 29 3 331 2 33 8 .

100 38 ...... ... 2 ...... 1 2 7 1 2 ...... 1 ...... .....4 01 18
98 63 .......... 16 7 1 6 7 ...... ... ... ... ........ 0 4 389
95 61 ..... .... 2 ...... 8 10 5 2 ...... .... 1 .. ...... .... ...... 0 2 0 86
90 60 ...... 1 2 13 1 ......... 1 ..... ... ... ...... 0 0 0 7 0 4
85 68 1 1 20 10 9 3 1 1 ........... ........... 0 4 17
79 71 -- ...- 14 10 5 4 7 2 ... .. ...... ..... ....... 2 1 0 2 4 20
'IU 49 -.... --.. -... ...... 1...... 2......1 2 1 2 ...... 1 .......... 1 0 0 1 2 36
61 53 ...... 2...... ....... 1 1 ..... 2 1...... 1 1 2 4 28
53 53 ...... ...... 1 2 ...... ...... ...... ..... ...... ..... ...... ...... ...... ...... 1 1 2 3 4 39
48 71 ...L........... 924 5 10 418
43 71 ...... ..........- - ...... ..... 5 9 2 4 ...... ...... ...... ...... 5 3 1 0 4 38
35 69 .................l 2 4 6 8 4 2 1 2 1 .......... 0 1 0 0 2 36
29 83 ... .... 1 6 2 6 1 6 1...... 1. ............ ...... 4 10 1 0 4 40
21 56 ...... ...... ...... .................. ...... 14 .. 2 2 0 1 1 0 27
14 50 ...... ...... ...... ...... ... ... ...... ......2 ...... 2 0 0 0 0 48
9 50 .... .. ...... ...... ...... .... ...... ......... ... ..... ..... ...... ...... 10 2 0 0 4 34
6 67 ..... ...... ... .. 6 ..... 1 ...... 1 ...... ...... ...... 1 ...... ...... ...... 3 9 0 0 0 47
3 77 ..... ...... ...... ...... .. ..... .. ..... ...... ...... ..... 1 2 1 24 5 0 5 61 33
2 60 ...... ...... ...... ...... ........0..... ...... ...... ..... ...... 0 0 0 01 60
1 49 ........... ...... ...... ...... ...... ...... 2 ...... ...... 1 ...... ...... ...... 5 5 0 2 1 33
21....l ..I........ 5 2 18

THE FLORIDA ENTOMOLOGIST

TIME OF HATCHING FIRST GENERATION BOLL WEEVILS
RELATIVE TO APPEARANCE OF BLOSSOMS'
By PAUL CALHOUN
Timeliness is a factor of first importance in the application of
poisons to control the cotton boll weevil. Applications made too
soon are partially wasted; those made too late fail in a meas-
ure-a very large measure at times-to accomplish their pur-
pose. An example of this is found in allowing first generation
weevils to hatch in sufficient numbers to puncture a consider-
able percentage of the young bolls before making dust applica-
tions in those cases where the hibernated weevils were not poi-
soned when the cotton was small.
In order to be able to predict with some degree of assurance
when one should expect first generation weevils to hatch where
hibernated weevils are not poisoned, the pre-bloom period dur-
ing which the first generation of weevils could normally be rear-
ing was determined for an Upland and a Sea Island variety of
cotton and correlated with the period required for a weevil to
hatch in the field. About 450 squares were measured and tagged
on Lightning Express 15-23 (Upland) and Seabrook (Sea-Island)
varieties. This was done from May 29 to June 6, while the plants
were in the pre-bloom stage. The time elapsing between the
date of measuring the squares and the date of blossoming was
recorded in each case. The average time required for each size
measured to blossom is shown graphically in Chart A, while
Tables I and II show more complete data for the sizes of chief
interest from the standpoint of possible producers of first gen-
eration weevils. It can be seen from the tables that most of the
blossoms occur within two days of the average calculated.
G. D. Smith* determined that the average time required
from egg to adult under field conditions at Madison, Florida,
was between 21 and 22 days. As the temperatures at Madison
differ but little from the temperatures of the greater part of the
Florida cotton belt, these figures may be considered sufficiently
correct for all practical purposes for the principal cotton grow-
ing areas of the state.
Referring to Chart A, it is evident that for a weevil to hatch
in an upland field before blossoming time it will have to develop
'Contribution from the Dept. of Cotton Investigations, Fla. Agric. Ex-
periment Sta.
*Bulletin 926, U. S. D. A. (1921) G. D. Smith.

WINTER NUMBER

TABLE I.-Time Required for Upland Squares of Various Sizes to Bloom.

TABLE II.-Time Required for Sea Island Squares of Various Sizes to Bloom.

p..
u u PBe
'5

Percent Blooming in Days

18 19 20

......... ............
........ ............
.... ..... ... ....
........... .....8

...... ............
........j............

......| ...........
........ ....... ......

..... 8

. .... 11 ..........
..... 12
... 33 33
12 25 12

............ ............

............ ...........

10 30
........... .....13
........... 25

11
41

12

from rather small squares. In the variety tested they would

have to develop in squares of about 4.5 millimeters diameter at

the time of oviposition. Weevils do not ordinarily develop in

smaller squares than this, as very small squares dry so readily

after they fall from the plants that the larvae they contain die.

On the other hand, it appears that first generation weevils find

no difficulty in hatching within three or four days after first

24 25

5

............

28
19
12
10

11

............

21 22

............ 28
............ 25
6 29
......... 40

............ 67
25 65
20 20
58 33

38 44
30 30
66 8
33 25

78 .........
41 .........
33 .........
39 ......

Average
Days

23.1
22.8
22.7
22.7

22.4
21.9
21.8
21.5

21.2
20.8
21.2
20.6

20.6
20.4
19.3
19.4

............ I ........................

13 ........... ............
8 ............ ............
8

6
............

............ ......
............ ......
........ ............
...................

CHART A.-Time Required for Squares to Bloom.
i IiI

Size of Squares Measured (in mm.)

WINTER NUMBER

blossoming time, as squares of from 5.5 to 6.0 millimeters di-
ameter easily produce adult weevils except under unfavorable
weather conditions. Although Lightning Express 15-23 was
the only Upland variety tried, it is not probable that other stan-
dard Upland varieties would show sufficient differences in the
pre-bloom period as measured to be of importance in weevil
control operations. Earliness has been one of the aims of most
cotton breeders for years, therefore, considerable uniformity is
to be expected in this regard. Some of the Sea-Island strains,
however, possibly would have a pre-blossom weevil breeding
period sufficiently long to permit first generation weevils to be-
gin to hatch several days before first blossoming.
Most growers do not realize that first generation weevils can
begin hatching so early. In fact, ordinarily they do not hatch
that early in sufficient numbers to cause damage, as generally
a large percentage of the eggs first laid never produce weevils,
because many of the immature stages are killed by the hot sun-
shine prior to the time the cotton is large enough to furnish
sufficient protective shade. On the contrary, if rainy weather
predominates from the time infested squares begin to fall, and
no hot sunny weather occurs, first generation weevils begin to
hatch in an infested field by the time blossoms appear, or very
shortly afterward. In this case they may easily become numer-
ous' enough to puncture many of the young bolls within three
weeks after the first blossoms occur.

NOTES ON UTAH COLEOPTERA
GEO. F. KNOWLTON
(Continued from page 56)
Stenocorus vestitus Hald.
Logan, August 13, 1921 (G. E. King).
Leptacmaeops subpilosa (Lec.)
Bountiful, 1929 (Pack); Cache Junction, June 3, 1912 (Hagan); Logan,
July 4, 1909 (Titus); Logan Canyon.
Acmaeops longicornis Lec.
Maryvale, June 25, 1906.
Leptura chrysocoma Kby.
Logan, July 30, 1904.
Typocerus velutina (Oliv.)
Logan, July 27, 1928 (Pack).

THE FLORIDA ENTOMOLOGIST

Rosalia funebris Mots.
Lewiston.
Callidium pseudotsuga Fisher
Logan, May 16, 1921 (G. E. King).
Phymatodes dimidiatus (Kby.)
Logan, June 28, 1904.
Oxoplus jocosus Horn
Fort Duchesne, August 13, 1926 (W. Sorenson); Mt. Pleasant, August
20, 1929 (Pack).
Crossidius pulchellus Lee.
Blacksmith Fork Canyon, August 17, 1929 (Knowlton).
Crossilius discoideus (Say)
Logan, August 21, 1927 (Knowlton) and Sept. 11, 1907.
Hyperplatys maculata Hald.
On cherry tree at Provo Bench, June 26, 1921 (G. E. King).
Pogonocherus parvulus Lee.
Logan, July 30, 1904.
Saperda populnea (L.)
Salinas, California, April 26, 1908 (Ball).
Saperda concolor Lee.
Logan, June 19, 1923 (Knowlton); reared from poplar, April 11, 1920
(G. E. King).
Mecas bicallosa Martin
Pleasant Grove, June 21, 1929 (Pack).
Tetraopes femoratus Lee.
Logan, July 3, 1923 (Knowlton). Also collected at Stanrod, Idaho,
August 13, 1929 (Knowlton).

Family CHRYSOMELIDAE
Donacia pusilla Say
Hyde Park, May 16, 1929 (Knowlton).
Griburius montezuma (Suffr.)
Bellevue, 1919.
Chrysochus cobaltinus Lee.
Hooper, September 1929 (Knowlton); St. George, 1919.
Zygogramma exclamationis (Fab.)
Salt Lake City, 1924; St. George, 1919.
Lina scripta (Fab.)
Watson, July 1927 (Pack).
Monoxia consputa (Lec.)
Ephraim, October 9, 1907 (Ball); on beets at Brigham, 1925 (Knowlton).

WINTER NUMBER

Diabrotica 12-punctata var. tennella Lee.
St. George, 1923 -(Hawley).
Disonycha quinquevittata (Say)
On rose at Spring Hollow, Logan Canyon, August 1925 (Knowlton).
Epitrix subcrinita Lee.
Common on beets at Logan, July 27, 1929 (Knowlton); Marysvale, June
29, 1906 (Ball); Sigurd, March 3,' 1928 (Knowlton); Sutherland, March 4,
1928 (Knowlton).
Systena taeniata (Say)
Common on Sugar-beets at Hyrum, September 2, 1926 (Knowlton);
Lehi, July 23, 1907 (Titus); Mendon, July 16, 1907 (Titus); North Ogden,
June 7, 1929 (Knowlton); Wellsville, June 1929 (Knowlton).
Psylliodes punctulata Melsh.
Common on sugar-beets at Amalga, May 27, 1924 (Knowlton); Delta,
July 12, 1926 (Knowlton); Lehi, July 23, 1927 (Knowlton); Lewiston, June
24, 1924 (Knowlton); Logan, June 20, 1907; also collected at Whitney,
Idaho, August 1, 1907.
Chelymorpha cassidea (Fab.)
Logan, June 18, 1923 (Knowlton).

Family MYLABRIDAE
Mylabris pisorum (L.)
Logan, September 1923 (Knowlton); Ogden, March 28, 1923 (Knowlton),
Providence, April 1, 1929 (Pack).
Mylabris obtectus Say
On beans, Tooele, 1916.
(To be continued)

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