Title: Florida Entomologist
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 Material Information
Title: Florida Entomologist
Physical Description: Serial
Creator: Florida Entomological Society
Publisher: Florida Entomological Society
Place of Publication: Winter Haven, Fla.
Publication Date: 1934
Copyright Date: 1917
 Subjects
Subject: Florida Entomological Society
Entomology -- Periodicals
Insects -- Florida
Insects -- Florida -- Periodicals
Insects -- Periodicals
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General Note: Eigenfactor: Florida Entomologist: http://www.bioone.org/doi/full/10.1653/024.092.0401
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Bibliographic ID: UF00098813
Volume ID: VID00287
Source Institution: University of Florida
Holding Location: University of Florida
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? he


Florida Entomologist
Official Organ of the Florida Entomological Society

VOL. XVIII APRIL, 1934 No. 1

EFFECT OF ARSENICAL AND COPPER INSECTICIDES ON
THE NATURAL CONTROL OF WHITEFLIES AND SCALE
INSECTS BY FUNGI ON ORANGE TREES IN FLORIDA
By
S. B. HILL, JR., W. W. OTHERS, and RALPH L. MILLER
U. S. Department of Agriculture
Bureau of Entomology
One of the most important considerations in the choice of an
insecticide for use on living plants is the effect it may have on
the tree or plant on which the application is made. In killing
insects on citrus trees one of the important requirements is that
the insecticide shall not destroy the great abundance of beneficial
entomogenous fungi present on the trees. When new materials
were being tried as insecticides against the Mediterranean fruit
fly in 1930, it was always important to know just what effect
these would have on the entomogenous fungi on the citrus trees.
Copper and arsenical insecticides having been found to be the
most promising, as reported in a paper by Miller and McBride',
these materials, with a few others, were used in the toxicity
work on entomogenous fungi. The effect of these materials
on citrus trees and fruit has been investigated by Miller and
Bassett2. The present paper is concerned mainly with the effect
of arsenical and copper insecticides on scale fungi and whitefly
fungi on citrus trees.
Method of Investigation.-Three citrus groves at Orlando,
Fla., were used for the experimental spraying in 1930. One
was of Valencia orange trees that were only about 7 years old,
another was of seedling trees some 30 or more years old, and
the third was of mixed seedling and budded trees. The spraying
was done with hand sprayers, and only small parts of the trees
were sprayed, following the method used during the Mediter-
ranean fruit fly campaign. A record of fungi present was made
SMiller, Ralph L., and McBride, O. C. Experiments with Copper Car-
bonate, Lead Arsenate, and Other Compounds Against the Mediterranean
Fruit Fly in Florida. Journ. Econ. Ent., vol. 24, no. 6, pp. 1119-1131. 1931.
2 Miller, R. L., Bassett, lone P., and Yothers, W. W. Effect of Lead
Arsenate Insecticides on Orange Trees in Florida. U. S. Dept. Agr. Tech.
Bul. 350, 20 pp. 1933.







..; i *
2 THE FLORIDA ENTOMOLOGIST

six to eight months after the first application. An accurate
record was kept of meteorological conditions, but only those data
that seem necessary or significant are given in this paper.
In both the Valencia and the seedling orange groves seven
trees were used in each plot. Three were left as checks and
four were sprayed. In some cases only half of a tree was sprayed
and this was checked against the unsprayed half.
Rainfall.-The rainfall during the period covered by the ex-
periment, June 1930 to April 1931, was 47.68 inches in the
Valencia grove, 43.13 inches in the seedling grove, and 65.36
inches in the mixed grove.
Effect on Whitefly Fungi.-Some 7 or 8 months after the first
spray application, 50 leaves on each of the treated and untreated
parts of the 78 plots were inspected to determine the abundance
of the citrus whitefly (Dialeurodes citri (Ashm.) ), the cloudy-
winged whitefly (Dialeurodes citrifolii (Morgan) ), and the
fungi attacking them. The fungi considered were the red
Aschersonia (Aschersonia aleyrodis Webber), the yellow Ascher-
sonia (Aschersonia goldiana Sacc. et Ellis), and the brown white-
fly fungus (Aegerita webberi Fawcett); these were found to
have been destroyed in approximately the same ratio, judging
from the numbers of parasitized whiteflies found on leaves that
had received different spray treatments. As a matter of con-
venience, only the percentages of live whitefly pupae are given
in table 1.
All the insecticides used in the Valencia and seedling groves
allowed an increase in the percentages of live whitefly pupae
found 8 months after spraying. On leaves sprayed with lead
arsenate, cryolite, and potassium aluminum fluoride there was
only a small increase, ranging from 11/2 to 5 times as many live
pupae as were found on the unsprayed parts of the trees. On
foliage sprayed with copper compounds there was a greater
increase, with from 5 to 10 times as many live whitefly pupae
in the sprayed plots as in the checks. Syrup and sugar did not
seem to have any influence on the fungus control of the white-
fly. The results secured in the Valencia and seedling groves
were fundamentally similar. The percentages in the last two
columns of the table show very clearly that the mixed grove had
different treatment. On investigation it was found that this
grove had been thoroughly sprayed with Bordeaux-oil mixture,
and consequently the data cannot be compared with those for
the other two groves; however, they may indicate what will hap-
pen when Bordeaux-oil mixture is used.









VOL. XVIII-No. 4


TABLE 1.-PERCENTAGES OF LIVE CITRUS WHITEFLY AND CLOUDY-WINGED
WHITEFLY PUPAE ON FIFTY CITRUS LEAVES EIGHT MONTHS AFTER
SPRAYING; ORLANDO, FLA., APRIL 1931.

Kind of spray o Valencia Seedling of Mixed grove'
lots Sprayed Check Sprayed Check plots Sprayed ICheck
I % C/% % % 1% %C
Lead arsenate,
8 pounds --.. 1 7 11.4 7.0 13.2 7.2 4 64.3 80.5
Bordeaux mixture,
4-4-50) ......... 5 56.5 6.8 77.0 4.7 8 85.0 71.0
Copper acetate,
4 pounds ..... .... .......... .... .............................. 4 64.0 46.5
Copper carbonate,
8 pounds --........... 6 36.4 14.5 14.8 2.6 4 28.1 35.1
Copper cyanide,
8 pounds ................ 2 50.5 3.1 67.0 12.4 .......... ..................... ..
Cryolite, 8 pounds..... 3 19.2 3.4 5.0 2.6 .......... -- ...... ...-
Potassium aluminum
fluoride, 8 pounds 3 9.0 5.4 4.6 2.8 ...... ... .--
Syrup and sugar
solution -....- ..- 1 .3 7.7 3.2 .7 4 60.5 36.4
1 For each spray (except Bordeaux mixture, which was of the formula
4-4-50) the given quantity of the chemical was used in 200 gallons of a
syrup and sugar solution made of 10 gallons of syrup and 50 pounds of
sugar in 190 gallons of water.
SThis entire grove had been sprayed with Bordeaux-oil mixture before
the counts were made, so the checks had been sprayed also.

From the preceding table it is evident that citrus growers, at
least in the vicinity of Orlando, Fla., can expect up to 90 percent
control of the whiteflies by fungi. When they spray with any
mixture containing a copper compound they may expect an in-
crease of from 5 to 10 times as many live whiteflies on the trees,
or only about 40 or 50 percent natural control.
Effect on Purple Scale Fungi.-Ten leaves on each plot were
very carefully examined under a binocular microscope some 6
to 8 months after the first spraying, and a record of the live and
fungus-killed purple scales was made. The fungi considered in
this examination were the pink scale-fungus (Nectria diploa B.
and C.), the red-headed scale-fungus (Sphaerostilbe aurantiicola
(B. et Br.) Petch), and the white-headed scale-fungus (Podonec-
tria coccicola (E. and E.) Petch). The effects of the various
materials on the scale populations are shown in table 2.
Lead arsenate, cryolite, potassium aluminum fluoride, and
syrup and sugar did not have any appreciable effect on the action
of scale fungi. All the copper compounds allowed the scale to
increase to nearly twice the normal population. Bordeaux mix-
ture was the most serious in this respect and copper carbonate
followed closely.









THE FLORIDA ENTOMOLOGIST


TABLE 2.-PERCENTAGES OF LIVE PURPLE SCALES ON TEN CITRUS LEAVES
EIGHT MONTHS AFTER SPRAYING; ORLANDO, FLA., APRIL 1931.


Kind of spray1


No.
of
plots


Valenc
Sprayed| Cl


I %
Lead arsenate,
8 pounds .............. 7 66.
Bordeaux mixture,
(4-4-50) ...............- 5 88. 4
Copper acetate,
4 pounds .....--------- ..- ..-... ........
Copper carbonate,
8 pounds ...-........ 6 77.6 4
Copper cyanide,
8 pounds -------.... 2 43.0
Potassium aluminum
fluoride, 8 pounds 3 50.7
Cryolite, 8 pounds.... 3 62.6
Syrup and sugar
solution ................------- 1 3.4


ia
ieck
%

37.
42.7


t0.3
59.5

59.4
52.0
58.5


Seedling
Sprayed ICheck
%38
36.8 36.0


90.0


68.5
93.0
49.0
60.6

49.5


43.5


53.0
43.6
53.2
40.4
52.7


No.
of
plots


4
8
4

4


Mixed grove2
Sprayed Check

81.5
81.5 69.


83.0

87.0
84.5


89.5 81.5


Citrus growers in the vicinity of Orlando, Fla., can expect a
natural control of about 60 percent on unsprayed trees, but when
Bordeaux mixture is used only about 20 percent control can be
expected.
The data for the mixed grove, as in the case of the whitefly
counts, serve only to show what an application of Bordeaux-oil
mixture will do to the live scale population.
Summary.-Lead arsenate, cryolite, and potassium aluminum
fluoride allowed whiteflies to increase on orange trees at Or-
lando, Fla., so that after 8 months the infestation was from 11/2
to 5 times as great as on untreated checks, while copper com-
pounds allowed whiteflies to increase to an infestation from 5
to 10 times as great as on the checks. Unsprayed groves at
Orlando may have a natural fungus control of the whitefly as
high as 90 percent, but when groves are sprayed with any mix-
ture containing a copper compound, such as Bordeaux mixture,
only about 40 or 50 percent of natural control can be expected.
Copper compounds used on orange trees at Orlando, Fla.,
allowed the purple scale to increase to a population nearly twice
as great as that on untreated checks. Lead arsenate, cryolite,
and potassium aluminum fluoride had no measurable effect on
the amount of scale fungus or on the live scale population. Bor-
deaux mixture was the most serious in allowing scale to increase
and copper carbonate followed closely. A natural control of
about 60 percent in unsprayed groves can be expected, but when
the groves are sprayed with Bordeaux mixture only about 20
percent control can be expected.








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

VOL. XVIII APRIL, 1934 No. 1

J. R. W ATSON.........-.......-........-..................................................Editor
E. W. BERGER ----.......----.. --..........------- .....------...... Associate Editor
H. E. BRATLEY.--....-........................----................ 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.

NON-ARSENICAL STOMACH POISONS FOR
GRASSHOPPER CONTROL
W. L. THOMPSON

Grasshoppers, as a rule, are not a serious pest of citrus trees
over three or four years old. During the fall of 1931, they did
severe damage in some orange groves in the central part of the
State. Due to recent legislation prohibiting the use of arsenicals
in citrus groves, except under special permission, it was neces-
sary to make some tests of non-arsenical stomach poisons to
control these pests.
The grasshopper doing the most damage was the "Bird Grass-
hopper", Schistocerca americana. It is one of our largest grass-
hoppers, long and slender, a powerful flier, and very active,
especially on sunny days. It is evidently a sun-loving insect,
as the trees were most severely damaged on the sunny side.
The grasshoppers used for the following experiments were
collected from one of the infested groves. Wire screen cages,
12"x14"x18", were used in the dusting, spraying, and a few
of the bait tests. The majority of bait tests were made in cages
of the above size but having no bottoms. In each test, potted
citrus plants were put into the cage, or the bottomless cages
were placed over young citrus trees in the nursery. In almost
every case the tests were started the day after the grasshoppers
were collected.
Kalo, a material made up of 96 percent sodium silicofluoride,
gave very good results when used in a bran mash. Kalo used
at the rate of 3 pounds to 50 pounds of bran, 1 gallon of syrup
and approximately 10 grapefruit, gave a 100 percent kill in two









THE FLORIDA ENTOMOLOGIST


to three days. A wire screen cage six feet square and six feet
high was placed over a three year old orange tree and the above
bait applied on the tree and ground. There were 80 grasshoppers
used in this experiment. In three days, 79 of the grasshoppers
were dead. The results of this experiment seemed to justify a
field test.
In the field test, the following formula was used.
TEST 52-Field Test.
Kalo, 3 pounds, Bran, 50 pounds, 1 gallon syrup, grapefruit,
15, water enough to make a stiff mash. This material was ap-
plied to four acres of Temple oranges about eight years old.
Approximately two large handfuls of bait was applied on and
around the east and south sides of each tree, since the most
damage was being done there. Most of the grass and weeds had
been killed by cultivation. This bait was applied between six
and seven o'clock in the evening.
Before application of the bait, an approximate average of
thirteen grasshoppers would fly from each tree when the foliage
was disturbed. After four and one-half days, observations were
made to determine the effect of the bait. An approximate aver-
age of two grasshoppers per tree was observed, or about an
eighty-four percent kill. Many trees had no grasshoppers on
them, the number ranging from zero to five per tree. A few
dead hoppers were found under the trees but due to the fact
that so much dead grass was on the ground, it was difficult to
find them.
The far side of the same grove, ten rows removed from the
treated section, was used as a check. There was no decrease
in the number of grasshoppers in this section of the grove during
four and one-half days.
The above observations were made from one to two-thirty
o'clock in the afternoon when the grasshoppers were very active.
Sodium fluoride, used at the rate of 1 pound -to 20 pounds of
bran and 2 quarts of syrup, gave a 100 percent kill in three to
four days. The combination gave better results than using 2
pounds of sodium fluoride to 20 pounds of bran, since a kill of
only 90 percent was obtained after six days. It is quite probable
that 2 pounds of sodium fluoride per 20 pounds of bran is dis-
tasteful to the grasshoppers.
Sodium fluoride, mixed with oat-meal and syrup, gave only
a 40 percent kill in six days. Sodium fluoride, as well as the
Kalo, should be sifted through a fine screen before it is mixed
with the bran as both of these materials are more or less lumpy.









VOL. XVIII-No. 1


Kalite, a dust containing 18 percent sodium silicofluoride, gave
a kill of 100 percent in six days when the plants and grasshoppers
were both dusted; but when only the plants were dusted, the
kill was but 55 percent in six and one-half days and ninety-nine
percent of the leaves were eaten off the plant. Kalite did not
stick well on the citrus leaves, but when a mixture of 3 parts
of Kalite to 1 part talc was applied, the adhesive qualities seemed
to be improved. Two different tests were made where five
grasshoppers were placed under a small wire screen and the
Kalite dusted over them and on the boards where they had to
crawl. No food was under these screens. After 48 hours all
the grasshoppers were dead and in the checks none. Whether
the grasshoppers died from the poison eaten when cleaning
themselves or whether it passed into the body through other
channels, was not determined.
Kaolith, made up of 94.26 percent sodium aluminum fluoride,
applied as a spray, gave only a 20 percent kill in six days, and
approximately ninety-nine percent of the leaves of the plant were
eaten. The adhesive qualities of this material is very poor on
citrus. By adding 1 percent of Penetrol, a sulfonated oil, a kill
of 70 percent was obtained in five and one-half days and 80
percent in eight and one-half days.
Copper carbonate baits and sprays gave only fair results.
Copper carbonate at the rate of 16 pounds per 200 gallons of
water, 50 pounds of sugar and 10 gallons of syrup, gave only a
36 percent kill in seven days. When the amount of copper car-
bonate was raised to 25 pounds with the same amount of the
above ingredients, a kill of 80 percent was obtained in five days
and 100 percent in seven days. After six and one-half days,
approximately fifty percent of the leaves of the plants had been
eaten and on the checks, ninety-nine percent. Copper carbonate
in a bran mash was tested in amounts from 2 pounds to 9 pounds
to 50 pounds of bran with syrup and grapefruit. The syrup
was increased from four quarts to six quarts to make the bait
more attractive, but the kill was not increased. In one test,
copper carbonate, used at the rate of 5 pounds to 20 pounds of
bran and 21/2 quarts of syrup, gave a 100 percent kill in five days.
A 5-5-50 Bordeaux mixture gave a 60 percent kill in five days
and 80 percent in ten days. A combination of a 5-5-50 Bordeaux
mixture and arsenate of lead at the rate of 4 pounds to 100
gallons of water gave only a 64 percent kill in seven days.
Neither bichloride of mercury nor strychnine gave any results
as a poison for grasshoppers.










ARTIFICIAL CONTROL OF GRASSHOPPERS (SCHISTOCERCA AMERICANA)


Applications


Dusts
Kalite- Plants and grasshoppers dusted........-- .............. ..... .............
Kalite-Plants and grasshoppers dusted.....----........ ...................
Kalite-Plants and grasshoppers dusted................................
Kalite-Plants dusted only........--................................ .... ....
Kalite 3 parts, Talc 1 part-Plants and grasshoppers dusted.........
Kalite 3 parts, Talc 1 part-Plants and grasshoppers dusted............
Check for tests 1, 2 and 5....................................... .
Check for tests 3, 4 and 6 ...................................

Sprays
Kaolith- 4 lbs. per 100 gallons.....................................
Kaolith-4 lbs. per 100 gallons plus Penetrol 4%......------.----...........
Arsenate of Lead- 2 lbs. per 100 gal...................... .....-..............
Arsenate of Lead-2 lbs. per 100 gal..........-----...--....----------------.
Arsenate of Lead-2 lbs. per 100 gal. plus Bordeaux 5-5-50...-......
Bordeaux Mixture 5-5-50-.......---.-..-......------------......--....
Copper Carbonate 16 lbs., Sugar 50 lbs., Syrup 10 gal., Water 200 gal.
Copper Carbonate 25 lbs., Sugar 50 lbs., Syrup 10 gal., Water 200 gal.
Check for test 9...........- ---- ........... ..-........................
Check for test 10, 11, 12, and 14-.. ----................ ..................
Check for test 13, 15, and 16...................--.........................

Baits
Sodium fluoride 2 Ibs., Oatmeal 20 lbs., Lemons 4 -....................- .
Sodium fluoride 2 lbs., Bran 20 lbs., Syrup 2 qts., Lemons 4-.............
Sodium fluoride 1 lb., Bran 20 lbs., Syrup 2 qts., Grapefruit 5........
Sodium fluoride 2 lbs., Bran 50 lbs., Syrup 1 gal., Grapefruit 15......
Paris Green 1 lb., Bran 20 lbs., Syrup 2 qts., Lemons 4 .....................
Kalite 1 part, Bran 9 parts, Syrup 2 qts., Lemons 4...--.....................


No. % %
Speci- Dead Days Dead
mens I


1.
2.
3.
4.
5.
6.
7.
8.


9.
10.
11.
*12.
13.
14.
15.
16.
17.
18.
19.


20.
21.
22.
23.
24.
25.


Days


80
86
60
5
84.6
85
5
5


10
60
10
13.7
16
15
4
36
5
5
0


5
35
85
92
80.9
0


Dead jDays ]


84.6
86.6
100
40
90
100
10
............


70
65
27.5
52
60.5
24
80
10
35
8


41/2
5/2
4
42
42
51/2
42




5%
51/2
5
51/2
5
5
41/2
61/2
4%2


84 32
86.6 32
801 3 2
20, 31/
84.6 3Y2
95 32
5 31/2
25 42

20 4
65 31/
30 41/
22.5 4/2


1 ....

5 3%
25 4/
4 3/2


5 3
85 32
95 3/2
100 3
95 3
0 32


DeadDays
Dead Days


100
100

55
90

60
35


20
80
85
37.5
64
80
36
100
60
85
32


40
90
............


25.....
25


62
6
6%
6Y
6%
62


6
82
10
12
7
10
7
7
6
10
7


6
6


|6%


* Screen cage, 6 ft. x 6 ft. x 6 ft. over three year old tree.


Test
No.


10 4
85 4 V
100 42

100 4
10 41/2


I


|


I











ARTIFICIAL CONTROL OF GRASSHOPPERS (SCHISTOCERCA AMERICANA) -Continued


No. %
Speci-j Dead
mens I


Applications


Baits (Continued)
Kalo 2 lbs., Bran 50 lbs., Syrup 1 gal., Grapefruit 10........................
Kalo 3 lbs., Bran 50 Ibs., Syrup 1 gal., Grapefruit 10.......................
Kalo 4 lbs., Bran 50 lbs., Syrup 1 gal., Grapefruit 10 ....................
Kalo 3 lbs., Bran 50 lbs., Syrup 1 gal., Grapefruit 10........................
Kalo 3 lbs., Bran 50 lbs., Syrup 1 gal., Grapefruit 15........................
Kalo 3 lbs., Bran 50 lbs., Syrup 1 gal., Grapefruit 15......................
Strychnine 10 gr., Bran 20 lbs., Syrup 21/2 qts., Lemons 4................
Bichloride of Mercury 1-200, Bran 20 lbs., Syrup 2 qts., Lemons 4
Copper Carbonate 5 lbs., Bran 20 lbs., Syrup 2% qts., Lemons 4
Copper Carbonate 3 lbs., Bran 50 lbs., Syrup 4 qts., Lemons 10
Copper Carbonate 4 lbs., Bran 50 lbs., Syrup 4 qts., Lemons 10
Copper Carbonate 5 lbs., Bran 50 lbs., Syrup 4 qts., Lemons 10
Copper Carbonate 6 Ibs., Bran 50 lbs., Syrup 5/2 lbs., Lemons 10
Copper Carbonate 7 lbs., Bran 50 lbs., Syrup 51/2 qts., Lemons 10
Copper Carbonate 8 lbs., Bran 50 lbs., Syrup 5/2 qts., Lemons 10
Copper Carbonate 9 lbs., Bran 50 lbs., Syrup 5% qts., Lemons 10
Copper Carbonate 6 lbs., Bran 50 lbs., Syrup 6 qts., Grapefruit 15
Copper Carbonate 7 Ibs., Bran 50 lbs., Syrup 6 qts., Grapefruit 15
Copper Carbonate 8 lbs., Bran 50 Ibs., Syrup 6 qts., Grapefruit 15
Checks for tests 42, 43, and 44..................-.. ....--..................
Checks for tests 20, 21, 24, and 25..... ........-.... ........ ........-..
Checks for test 22...................... ................... ....
Checks for tests 23, 26, 27, and 28.....................-.................
Checks for tests 29, 33, and 34 ...-........... .........................
Checks for tests 30, 31, 32, 35, 36, and 37....................................
Checks for tests 38, 39, 40, and 41.....-----.......--......... .......-..


25
25
25
25
25
80
25
25
25
25
25
25
15
15
15
15
15
15
15
15
20
20
25
25
25
30


96
100
96
100
96
25
0
4
80
20
24
20
46.6
53.3
53.3
33.3
33.33
46.66
40
6.66
5
5
0
0
0
3.3


Days


2
2
2
21/2
2
1
11/2
2
3
11/2
1Y2
11/2
2
2
2
2
2
2
2
2
21/2
2,y2
2
21/2
212
2


Test
No.


% I I%
Dead ;Days I Dead IDays


4


Dead



100
----- .....- -
96

100
50
8
8
100
68
52
64
53.3
66.6
86.7
60.6
53.33
66.66
66.66
13.33
5
25
4
4
4
9


Days



3
3

3
2
41/2
5
5
31/2

3 Y2
31
3
3
3
3
3
3
3
3
31/2
41/2
3
31/2
31/2
3


97.5 3
12 51/2
24 7

72 4 "Y2
76 41/2
80 41/2
73.3 4
66.6 4
86.6 4
86.6 4
80 4
80 4
73.33 4
20 4
10 41/2
35 6Y2

8 41/2
8 41/2
15.1 4


i...........


v


I


76 51/2
96 5/2
88 5/2
86.6 6
86.6 6
93.3 6
86.6 6
86.6 7
80 7
93.33 7
26.66 7
60 612
85 10

32 7
12 5%
24.2 6










10 THE FLORIDA ENTOMOLOGIST

INGREDIENTS OF MATERIALS USED
SSodium silicofluoride ...........................------ -.................. 18.0%
Kalite Sulfur ------.......... ................----------------------... ------ 19.0%
f Inert ingredients..............-----------------....... .........-- 62.0%
Kaolith Sodium aluminum fluoride..................----------------- 94.26%
Inert ingredients...........--- ..-------..... -- -- --------------........ 5.24%
Kalo Sodium silicofluoride .-.... -----.............. -- --- ...-..- 96.0%
Inert ingredients... ----------.....--- ----------4.0%
Sodium fluoride-active ingredients ---...--....... ----------.......... 90-95%
Arsenate of lead-active ingredients..-----....... --..----- ..-----..-- 98%
Copper-active ingredients--Metallic copper--- ----........................- ......... 18%

OBSERVATIONS OF TREATED PLANTS EXPOSED TO
GRASSHOPPERS
Leaves
eaten
Kalite 34, Talc %, dusted on plants and grasshoppers 5% after 61/ days
Kalite dusted on plants and grasshoppers------................... 1% 6/2
Kalite dusted on plants only ---............- --..-........... 99% 61/z "
Kaolith, sprayed on plants only.....................---------............... 99% 6
Lead arsenate, 2 lbs.....................--------... ---------90% 6
Check .----.............. -------------.-------- 99% 6%
Strychnine Bran Bait.....--------------................. ............ 99% 6% "
Kalo Bran Bait....------- --..............--------- .. 1% 61/2
Sodium fluoride bran bait--......................--- ......... 1% 6 "
Copper carbonate spray...................... .............. ...... 50% 61 "

Out of 200 grasshoppers that were not exposed to poison, only
six parasites were observed. The parasites were tachinid flies.
Sodium fluoride and Kalo gave the best results and were the
most economical. Both of these materials compare with the kill
obtained by using Paris green bran bait in like amounts. No
burning of foliage was observed when sodium fluoride or Kalo
were used in the bran bait, which was thrown on the plants.
Copper carbonate gave only fair results, unless used in rather
large amounts.
The table on page 9 gives in detail the results of the various
experiments.


DR. HERBERT OSBORN ADDRESSES ENTOMOLOGICAL SOCIETY
On April 2 the members of the Florida Entomological Society
and visitors were treated to an illustrated lecture on the "History
of Entomology in the U. S. and Canada." Dr. Osborn showed
lantern slides of most of the early entomologists and spoke
briefly of the work of each.
The speaker was introduced by Dr. P. H. Rolfs who has recent-
ly returned from Brazil. Three other former students of Dr.
Osborn were present, Drs. E. W. Berger, Wilmon Newell, and
A. N. Tissot.









VOL. XVIII-No. 1


THE EFFECT OF COOL TEMPERATURES ON SOME
STAGES OF THE CIGARETTE BEETLE
S. E. CRUMB and F. S. CHAMBERLIN
U. S. Department of Agriculture
Bureau of Entomology
The use of cool chambers for the storage of surplus stocks of
cigars has made it important to determine the effect of these
moderately cool temperatures on the cigarette beetle (Lasioder-
ma serricorne Fab.). The temperatures employed range from
500 to 650 Fahrenheit. Pook', Jones2 and Runner" have shown
that with exposure to temperatures below 320 F. for a sufficient
period all stages of the beetle can be killed, but the only recorded
experiments with temperatures such as are in use for cigars in
the storage chamber are those of Jones', who carried out a short
series of tests on each of the stages of the cigarette beetle at
temperatures ranging from 460 to 570 F.
In these experiments by Jones it was found that some of the
eggs hatched after an exposure of 20 days, but that none of the
small and half-grown larvae lived more than 30 days. The large
larvae, pupae, and adults, however, were found to be very much
more resistant. Large larvae lived for as much as 157 days, the
pupae transformed to adults, and the adults lived for 111 days.
Jones did not establish an exposure which would destroy the
viability of all eggs, and, since stages of the beetle other than
the egg and the small larvae are very rarely found in fresh
cigars, the writers carried out a series of experiments at Tampa,
Fla., and Clarksville, Tenn., during 1927 and 1928 in an effort
to establish the proper periods of exposure for eggs and small
larvae at several temperatures. A few experiments also have
been carried out with large larvae and pupae.
These experiments were conducted under conditions of com-
mercial storage and the temperatures and humidities used were
those actually occurring in commercial practice. Humidity
ranges in the storage rooms were such that it is unlikely that
any of the mortality indicated is the result of excessive dryness.
Under the conditions existing at the beginning of the experi-
ments, it was not possible to obtain accurate counts of the insects
involved without disturbing their positions and crushing the
1 Pook, Gustav. 1910. Die Anwendung von Kalte zur Verwichtung des
Tabakwurms. Chemiker-Zeitung, Jahrg. 34, No. 126, p. 1127.
SJones, C. R. 1913. The Cigarette Beetle (Lasioderma serricorne
Fabr.) in the Philippine Islands, Philline Jr. Sci., Ser. D, vol. 8, No. 1,
pp. 1-39, illus.
SRunner, G. A. 1919. The Tobacco Beetle: An Important Pest in
Tobacco Products. U. S. Dept. Agr. Bul. 737, p. 77, illus.









THE FLORIDA ENTOMOLOGIST


eggs or young larvae. The cigars must be entirely free of all
living stages of the beetle, as the whole box may be returned
to the manufacturer upon detection of a single sign of infesta-
tion. Thus detailed counts of the extent of the infestation after
treatment are not particularly important, as the presence of
any living stages, however few, in the treated cigars, invalidates
the treatment.
In these experiments an exact duplicate of the treated material
was reserved as a check, unless otherwise noted, and both lots
of material were kept under the same conditions both before
and after exposure. Where cigars were used, these were fresh
and were packed in a box with sufficient paper to prevent them
from rolling about. The boxes were sealed with adhesive tape
or with strips of paper. Usually 100 specimens were exposed
in each experiment.
The various "stations" referred to in the table were of the
character indicated below.
Station No. 1 was the humidor of a cigar factory. The daily
temperature fluctuated mainly between 500 and 60 F., with
brief periods of higher and lower temperatures, and there were
a few isolated days during which the temperature was main-
tained between 600 and 70' F. The relative humidity usually
ranged between 45 and 50 per cent.
Station No. 2 was a cave. The material was placed well back
where the temperature was constant at 560 F. The relative
humidity was high.
Station No. 3 was the humidor of a cigar factory. The tem-
perature was maintained at about 650 F., varying two or three
degrees above or below this temperature. The relative humidity
was taken only a few times and ran about 95 per cent.
The details of the various "conditions" referred to in table 1
are as follows:
"Vials." Eggs of the cigarette beetle were placed on a slightly
moistened strip of tobacco which was then inserted in a vial
having a cover of cheesecloth over the mouth. This vial was
inserted in a second vial containing moist tobacco and the screw
cap of the outer vial was screwed down tightly.
"Capsules." A hole was made in the bottom of a gelatin cap-
sule and a compact wad of pliable tobacco was forced into the
capsule, closing the hole, after which larvae, or eggs on a strip
of tobacco, were introduced. The capsules were then given to
a cigar maker, who rolled one or two capsules into each cigar.
This arrangement allowed the larvae to escape into the cigar
after the tobacco in the capsule had been consumed.










TABLE 1.-EXPERIMENTS IN THE TREATMENT OF STAGES OF THE CIGARETTE BEETLE BY PROLONGED EXPOSURE TO COOL
TEMPERATURES, TAMPA, FLA., 1927-28.


Results


Treated


Stages
Treated
Eggs
do
do
do
do

do
do
do
do
do
do
do
do
do
do
do
do
do
do
do
do
do
do
Newly
Hatched
Larvae
do
do
do
Large
Larvae,
Pupae
do
do
do
do
do


Check


Condition
Capsules
do
Cigars
Vials
Leaf

do
Cigars
Capsules
Vials
Leaf
Cigars
Vials
do
do
do
do
Capsules
do
do
Cigars
Leaf
Capsules
Leaf

Slit cigars

do
do
do

Capsules

do
do
do
do
do


Sta.
No.
1
1
1
1
1

1
1
1
1
1
1
2
2
2
2
2
3
3
3
3
3
3
3

1

1
1
1

1

1
3
3
3
3


Temp.
F.
50-60
50-60
50-60
50-60
50-60

50-60
50-60
50-60
50-60
50-60
50-60
56
56
56
56
56
65
65
65
65
65
65
65

50-60

50-60
50-60
50-60

50-60

50-60
65
65
65
65


Expo-
sure
Days
8
15
21
23
28

30
31
35
40
47
53
16
24
33
41
47
12
18
28
29
32
42
47

21

31
32
42

22

45
12
42
53
59


Hatched after removal.
Some hatched after removal.
A few hatched after removal.
1 out of 60 hatched after removal.
Hatched, possibly before entered. No
larvae in cigars.
Few hatched, one live larva.
1 out of 100 hatched after removal.
None hatched.
do
do
do
Hatched after removal.
6 out of 100 hatched.
None hatched.
do
do
Hatched before removal.
do
do
Hatched, two live larvae in cigars.
Hatched, larvae dead.
Hatched, 2 larvae alive.
Hatched, larvae dead.

None alive.

do
do
do

Nearly all alive.

Many alive, one punctured cigar.
Nearly all alive.
About 16 per cent survived.
Cigars punctured, live adults and larvae.
Cigars punctured, live adults and larvae.


Results


do
do
do

Alive.

Nearly:
No ch
do
do
do


y all cigars punctured.
eck.


Eggs hatched.
do
Cigars very wormy.
No check.

A few larvae.
do
Cigars very wormy.
Eggs hatched.
do
A few larvae.
All cigars punctured.
Eggs hatched.
do
do
do
do
No check.
do
do
Nearly all cigars punctured.
No check.
do
A few larvae in cigars.

Only a few alive.








THE FLORIDA ENTOMOLOGIST


"Leaf." Beetles were allowed to oviposit on leaf tobacco and
this was placed among cigars in a sealed box.
"Cigars." Fresh cigars were packed, open end up, in quart
jars containing a large number of beetles. The cigars were
removed and entered in experiments after they had become
heavily infested with eggs.
"Slit Cigars." A slit was cut in fresh cigars and into this
slit eggs of the tobacco beetle were inserted, 10 or more to each
cigar, after which the cigars were kept under favorable condi-
tions until the eggs were hatched.
The results of these experiments are indicated in table 1.
We draw the following conclusions from the results of these
experiments:
At a temperature of from 500 to 600 F. eggs do not hatch and
they are nonviable upon removal to normal temperature after
an exposure of 35 days; a limited number of experiments with
just-hatched larvae indicate that these larvae do not survive an
exposure of 21 days; large larvae survive for at least 45 days
and sometimes puncture cigars at this temperature.
At 560 F. eggs do not hatch, and they are nonviable upon
removal to normal temperatures after an exposure of 33 days.
At a temperature of 650 F. development of all stages of the
beetle continues at a reduced rate; eggs hatch, larvae pupate,
adults emerge, and adults and the surviving larvae puncture
the cigars. The newly-hatched larvae seem to be very susceptible
to reduced temperature and very few small larvae survive after
the eggs and resulting larvae have been exposed for a period
of 32 days at this temperature.
Since stages other than the eggs and very small larvae occur
very rarely in fresh cigars, it seems that storage of fresh cigars
at a temperature of 550 F. for a period of 35 days should provide
a satisfactory control of the tobacco beetle if sufficient care is
taken to prevent reinfestation after the cigars are removed
from storage.


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