Papers on deciduous fruit insects and insecticides

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Papers on deciduous fruit insects and insecticides
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Table of Contents
    Front Cover
        Page i
        Page ii
    Table of Contents
        Page iii
    Introduction
        Page 81
        Page 82
    Results
        Page 83
        Page 84
        Page 84-1
        Page 84-2
        Page 85
        Page 86
        Page 87
        Page 88
    Miscellaneous tests
        Page 89
    Conclusions
        Page 90
    Back Cover
        Page 91
        Page 92
Full Text
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ISSUED JANUARY 17, 1913.


WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1913.


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U. S. DEPARTMENT OF AGRICULTURE,
BUREAU OF ENTOMOLOGY-BULLETIN No. 116, Part IV.
L. 0. HOWARD, Entomologit and Chief of Bureau.


PAPERS ON DECIDUOUS FRUIT INSECTS
AND INSECTICIDES.




LIME-SULPHUR AS A STOMACH POISON

FOR INSECTS.



BY

E. W. SCOTT AND E. 1I. SIEGLER,
Entomological Assistants, Deciduous Fruit Insect Investigations.























BUREAU OF ENTOMOLOGY. i

L. 0. HOWARD, Entomologist and ChieJ o] Bureau. i
C. L. MARLATT, Entomologist and Acting Chief in Absence oj Chiej.
R. S. CLIFTON, Executive Assistant.
W. F. TASTET, Chief Clerk.

F. H. CHITTENDEN, in charge of truck crop and stored product insect investigations.
SA. D. HOPKINS, in charge ojjorest insect investigations. il
W. D. HUNTER, in charge of southern field crop insect investigations. .:i.;.ii
F. M. WEBSTER, in charge of cereal andjorage insect investigations. J
A. L. QUAINTANCE, in charge of deciduous fruit insect investigations. i
E. F. PHILLIPS, in charge of bee culture. .iiii
D. M. ROGERS, in charge of preventing spread of moths, field work.. i
RoLa P. CURRIE, in charge of editorial work.
MABEL COLCORD, in charge of library. :

DECIDUOUS FRUIT INSECT INVESTIGATIONS.
A. L. QUAINTANCE, in charge.
'ii
FRED JOHNSON, F. E. BROOKS, A. G. HAMMAR, E. W. SCOTT, R. L. NouGmn ..
R. A. CUSHMAN, L. L. ScoTT, J. B. GnL, A. C. BAKER, W. M. DAVIDSON, E. B.
BLAKESLEE, W. B. WooD, E. H. SIEGLER, F. L. SIMANTON, entomological assistant.
3. F. ZIMMER, W. S. ABBOTT, W. H. SML, entomological assistants, employed in enforce-
ment of insecticide act, 1910.
.1








lil











.1
.. t..:: ::























CONTENTS.

P ze.
Introduction .............................................................. 81
Conditions of the experiments ..................... .......................... 81
R results ................................................................... 83
Miscellaneous tests ......................................................... 89
Conclusions ............................................................... 90





IL LUSTRATIONS.


PLATES.
Page.
PIATE XI. Fig. 1.-Sprayed twig of wild cherry showing larve of the fall
webworm (Hyphantria cunea) feeding on leaves; at right, same, covered with
paper bag, to prevent escape of larvae. Fig. 2.-Unsprayed twig of wild
cherry upon which fall webworms have been feeding for some time; for
comparison with sprayed twig .................................................. 84
In






Page
Missing
or
Unavailable





DECIDUOUS FRUIT INSECTS AND INSECTICIDES.


was rather resistant against the burning effect of the spray materials.
Twigs bearing from 20 to 30 leaves were employed..
The spray was applied to the foliage by means of a large atomizer :
of the type in which quart jars are used as a container for the liquids :*
The twigs were sprayed until the leaves began to drip, approaching"
as nearly as possible the conditions of field spraying operations.'
Each sprayed twig was then placed in a jelly glass of water, the
stem extending through a hole punched in the tin cover. (See Plat1i
XI, figs. 1, 2.) NI
After the spray had thoroughly dried, allowing from 6 to 12 hours, I
20 insects were placed on the leaves of each twig. A large paper 3
bag was then placed over the twig and held to the glass by means of a W
rubber band. (See Plate XI, fig. 1, at right.)
Observations were usually made every other day; in some cases
every clay. At each examination the bag was removed and the dead
larvae taken out and counted. When all the insects were dead, or
had pupated, as the case might be, the amount of foliage consumed
was measured in square inches. A sheet of celluloid cross-sectioned,
to one one-hundredth of a square inch was utilized for this purpose.
These measurements were easily taken, where effective poisons.
were used, as the young larvae died before very much foliage had
been consumed. The younger larvae ate only one surface of the leaf,
but as they increased in size the leaves were often skeletonized.:.
Owing to this fact it became necessary to differentiate between the
one and two surface feedings. Therefore, in order to equalize these
conditions, the measurements of the one surface feeding were divided
by two. Another difficulty in securing feeding measurements in the'.;
case of unsprayed twigs used as checks was encountered when tile
entire leaf, except the midrib and larger veins, was consumed. Ih
such instances the outline of the leaf was nearly obliterated, thus
rendering actual measurements in the ordinary way impossible.
However, since the leaves of the wild cherry selected for the experi-
ments were fairly uniform in size, this difficulty was overcome by
taking the measurement of an average-size leaf and substituting it
for the leaf the outline of which had been destroyed. This method
gave approximately accurate results. Careful attention was given
to the condition of the foliage throughout the experiments so as to
supply the larvae with palatable food at all times. It was seldom
necessary, however, to renew the foliage, except for the unsprayed
lots, which were quickly devoured. 6
Commercial lime-sulphur testing 33 Baum6 was used at strengths 2
varying from 1-50 to 6-50.1 In lots 4 and 5 of Table VI home- ......
boiled lime-sulphur testing 30 Baum6 was used at the rate of 1"-S0.
I All the strengths indicated as above signify a given quantity of poison diluted with water to make I :
total of 50 gallons of spray material. For example, lime-sulphur, 11-50, means 1i gallons conoetmtq. ,1
lime-sulphur solution diluted with water to make 50 gallons of spray material. Aenate of lead, 2-UI
means 2 pounds arsenate of lead diluted with water to make 50 gallons of spray material. j



:4


82






LIME-SULPHUR A STOMACH POISON FOR INSECTS. 83

Arsenate of lead at strengths varying from -50 to 5-50 was used
in comparison with the lime-sulphur solution. Arsenate of lead and
lime-sulphur were also used together at various strengths (Tables
I and IV). In the case of the arsenate of lead and the lime-
sulphur most of the feeding was done during the first three or four
days. However, in no instance was there much feeding during the
first 24 hours, as the larvae were more or less unsettled until they
found a suitable place for their web. This was true on the unsprayed
as well as the sprayed leaves.
It will be found in the following pages that the rate of killing is
fairly uniform in all experiments. Since, however, the tests were
conducted throughout the season under different climatic conditions,
slight variations exist.
RESULTS.
EXPERIMENT I.
The results given in Table I are taken from an experiment to obtain
data on the killing effect on the fall webworm of various chemicals
combined with lime-sulphur. Lot 1 was the unsprayed check; lot 2
was sprayed with lime-sulphur alone at the strength of 1 --50, and
lot 3 with lime-sulphur, 11-50, in combination with arsenate of lead,
2-50. In the course of a few days it was observed that several larvae
on the lot sprayed with lime-sulphur were dying. The 20 larva of this
lot were dead at the end of 13 days, as against 7 days required to kill
all the larvae with the combination of arsenate of lead and lime-sul-
phur. On the unsprayed lot, at the end of 72 days, 4 larvae were
recorded dead, 12 had pupated, and 4 were missing.
TABLE I.-Tests of the killing effect on the fall webworm of lime-sulphur alone and com-
bined with arsenate of lead.
[Experiment started July 20, 1912, Benton Harbor, Mich., 20 larvae in each lot.]

Larvae dying in each lit. Larvae dying in each lot.

Lot 3- Lot 3-
Lime- Lime-
Date of examina- Lot 1- Lot 2- sulphur, Date of examina- 1- Lot 2- ph,
tion. Check Lime- 1P"0, tion. LOt 1-- Lot 2-- sulphur,
ton. Check Lime- 1-50J tion. Check Lime- 1j-50,
(un- sulphur, and (un- sulphur, and
sprayed). 1--50. arsenate sprayed). 11-50. arsenate
of lead, of lead,
2-50. 2-50.

July 22-------------- I......... .......... Aug. 12 ...................
23............................. .......... ... 1......... 1...............................
24......... ..... .......... 1 16......................
25 ------------ ---------- ---------- 7 18 ...... ............ ........ .........
26 --------------------- 4 10 21......... ......................
27 ------------ ---------- 3 2 23............ ... .... ................
28............- .......... 3 Sept. 2 ........... I........ ..........
29.. --------- --- ---------- 4 .......... 19 ............. 2....... .........
30 ............ ... .. .... ... ...... .. ...3.. .. ... .. ......... ..........
31-.. -.........I...... 4 .......... ----
Aug. 1 .. ...... .......... .................... Total number
2 -..-.--.-... .......... 2 .......... dead....... 4 20 20
3 ............ ......... ......... ........ Number of days re-
6........... .. .......... .......... quired to kill ............... 13 7
......... .. ..........Square inches of
9. .... ........ ........- foliage consumed. 243.20 0.73 0.12






84 DECIDUOUS FRUIT INSECTS AND INSECTICDES. I

ExPE RwzNT II. r1
.. ..- ( 3l
In order to obtain further data on the killing effect of lime-sul]u

another experiment was started July 30, using different strength
lime-sulphur as given in Table II.

TABLE II.- Tests of the killing effect of lime-sulphur on the fall U ebw :on.

[Experiment started July 30, 1912. Benton Harbor, Mich.; 20 larvae in each lot.]


S Lar-vae dying in each lot.

Da-e-----------------
T^. f Lo iLot Lot Lot Lot
Date of i _i '
examination" ,Check Lime-: Lime- Lime- Arse" I
I(un- suIl-sul- sul- oate
spray- phur, phur, phur, 1,
ed). 1"-5 -0. 3 -50. 60 ;


Aug. 1 ................. .... ......... .......
2...... ...... .. .... .... .... .....
........... ...... 2 ....... ...... i. ......
4 ................... ...... 1 3 ..... .
5- ........ ...... .. 1 1 5' 6
6 ........... ...... ...... ... .. 3 --.-.-.
7 .......... 1 1 9 8 ......
8 .. ..... ......... 3 4 1' 14 ,
9........... .. 2. '. 4 ...... ......
10..... 2 ... ...... ...... ,.
11. ..... .......... 4 1 -
12..i : l
12 ........... ... ............. ...... ......
13 ........... ... 2 ...... ...... ......
i, ,:


Date of
examination.


Larvae dying in eah lot'.
---------------'- c c.ii


Lot
1-
Cheek
(un-
s ay -


Lot
2-
Lime-
sul-
phur,
1_0.


Lot
3-
TLiftne
sul-
phur,
3-5&


I I


Aug. 14... ........ ...
15 -----..... .. ....
20..... ..... ......
25.. ........ ....
29 ........... ......
Total num-
ber dead. 1
Number days re-
quired to kill .... ......
Square inches foli-
age consumed... 40.00


2


Lot
4-
sni-
phur,
6-5t


I il-b-


20
15
1.21


20
12
0.65


20
9
0.34


I Arsenate of lead was used in lot 5 for comparison with the lime-sulphur solution.


-a
p
*4~


-t
4~1


In this experiment 15 days were required by lime-sulphur, 1j-MS)|
to kill the 20 larvae, as against 9 days required by arsenate of 1e4d
2-50. Twelve days were required by lime-sulphur, 3-50, while liMi.::
sulphur, 6-50, killed the 20 larvae in the same length of time required
by arsenate of lead, 2-50. The check lot was discontinued at thii
end of 30 days, when 1 larva was recorded dead and 40 square inche:
of foliage consumed. It was found in this test that the number o|,
square inches of foliage consumed decreased about one-half as th
strength of the lime-sulphur was doubled, the largest amount being
1.21 square inches. The amount consumed on the arsenate-of-le d.
lot was 0.83 of a square inch..

EXPERIMENT III.

In Table III are shown the comparative results of a dosage totS
consisting of seven different strengths of lime-sulphur varying froal
4-50 to 6-50, and four different strengths of arsenate of lead varyi"|
from 1-50 to 5-50. *i!|


I






































FIG. 1.-AT LEFT, SPRAYED TWIG OF WILD CHERRY, SHOWING LARVAE OF THE FALL
WEBWORM (HYPHANTRIA CUNEA) FEEDING ON LEAVES; AT RIGHT, SAME, COVERED
WITH PAPER BAG TO PREVENT ESCAPE OF LARVAE. (ORIGINAL.)


METHOD OF TESTING LIME-SULPHUR AS A STOMACH POISON


FIG. 2.-UNSPRAYED TWIG OF WILD CHERRY
UPON WHICH FALL WEBWORMS HAVE
BEEN FEEDING FOR SOME TIME; FOR COM-
PARISON WITH SPRAYED TWIG. (ORIGINAL.)

AGAINST THE FALL WEBWORM.












































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LIME-SULPHUR A STOMACH POISON FOR INSECTS. 85

TABLE III.-Teats of the killing effect on thefall webworm of lime-sulphur in comparison
with arsenate of lead.
[Experiment started August 8. 1912, Benton Harbor, Mich., 20 larvae in each lot.]

Larvae dying in each lot.

I Lot Lot Lot Lot LoLOt Lot Lot Lot Lot Lot
Date of examination. hLot 1 2- 3- 4- 5- 6-- 7- 8- Arse. Arse- Arse- Arse-
(Check Lime- Lime- Lime- Lime- Lime- Lime- Lime- Ae Ae nae nae
(Un- su. sul- sul- sul- sul- su- su- nate ate ate ate
spray- of of of of
"py phur, phur, phur, phur, phur, phur., phur, lead, lead, lead,
ed). I a-s. 1-50. i-50. 2-50. 3-50. 5-50. l 6-50., 'l l e
-50 1-50. 2-50. 5-50.

A ug. 10 .................. ........ .. .............. ....... ...... 2 ...... 2 8 4
12 ................... .... ................... ... ...... ... 1i 3 ..... 2 11 15
14 .................... i 4 1 5 j 2 J 3 6 : 11 1 10 1 1
16; .........-.- .. .....--- .- .. -3 81 13 6 6 (1 4 11 2 ............
18 ... .. ..... .... ... 2 8 2 i S 11 7 ...... 3 4 ...........
20 ................... .. .. ...... ..... 4 !. .... ..... ... 4 ..... .. .....
22 .................. .. .... ... .. ... ... ...... ... .....
Sept .................. 2 ......... .......I .... ... ... ...... ......... ... ..................
10 ................... 3 ........................ ...... ....... ......... .... ............. ......
O ct. 19 ................... 2 ..... ... i .... .. .. ... ...... ... .. ...... ...... ...... ....... ......
Oc.l.-- .--------------2...........
Total number dead. 7 20 9- I 20 20 20 20 20 20 20 20 20
Number days required to 1 ,
kil .................... ......... 14 10 i 10 12 10 10 S 14 10 G 6
Square inches of foliage 1 0 I 2
consumed ..............' 119.00 3.92 0.36 0.17 1.01 O.,I 0.73 0.26 2.3S 1.98 0.11 0.10

It will be noted that lime-sulphur, 4-50, killed the 20 larvae in 14
days, the same length of time required by arsenate of lead, 1-50.
Also lime-sulphur, 1-50, killed the larvae in the same length of time
as arsenate of lead 1-50, the time required being 10 days. However,
in both instances the arsenate of lead killed more rapidly in the
beginning than the lime-sulphur. Eight days were required by
lime-sulphur, 6-50, to kill the 20 larvat as against 6 days required by
arsenate of lead, 5-50. The amount of feeding varied somewhat in
this experiment, the largest amount on the sprayed lots being 3.92
square inches where lime-sulphur, j-50 was used, and the smallest
amount being 0.10 of a square inch in lot 12 which was sprayed with
arsenate of lead, 5-50.
EXPERIMENT IV.

The object of experiment IV was to obtain data on the relation of
the killing effect of arsenate of lead alone and combined with lime-
sulphur, and to obtain, if possible, data on the effect the addition of
one to the other has upon the rapidity of killing. Lime-sulphur
alone was used at four different strengths, and also was combined at
the same rates with arsenate of lead, 2-50. The lime-sulphur
strengths employed were }-50, 3-50, 14-50, and 3-50. Arsenate of
lead, alone, was tried out at strengths of 1-50, 1-50, 2-50, 3-50, and
5-50, and also at the same strengths was combined with lime-sulphur,
1 -50. The results are given in Table IV.





n^ n


60 DECIDUOUS FRUIT INSECTS AND INSECTICIDES.

TABLE IV.-Tests of the killing effect on the fall webworm of lime-sulphur and arsenate
of lead, alone and combined.

[Experiment started Aug. 19, 1912, Benton Harbor, Mich., 20 larve in each lot.]

Larvme dying in each lot.


Date of examina- Lot I Lot 2- Lot 3- Lot 4-
tion. Check Lime- Lime- Lime-
(un- sul- sul- sul-
sprayed). phur, phur, phur,
1_-50. 1-50. l2-so.


Aug. 21 ......... ............. .... .. 1 ........
23............ I ........ 1 2 2
25....................2 1 8
27 ............ ........ 8 7 10
29 ....... ... .
3 1 .. .. .. .. .. .. .. .. .. :12 .. .. .. .
S ep t. 2 .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. .
4 .. . .. .. . .. .. .. . I. . ..
0 .... ....... ..... ... .. .. .. ... .. .. ... .... ..
150 ............I 3 ... .. ... ... ...........
O t. 3 ............ 5 ........ ........ ........

Total num-
ber dead... I 20 20 20
Number days re-
quired to kill............. 12 12 8
Square inches of i
foliage consumed. 72.00 3.51 2.87 0.17


Lot 5-
Lime-
sul-
phur,
3-50.


3
2
9
6


Lot 6-
Arse-
nate of
lead,
1-50.


2
8
7
3


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





20 20

8 10
0.49 2.44


Lot 7-
Arse-
nate of
lead,
l 1-50.


3
10
7










20
6

0.36


Lot 8-
Arse-
nate of
lead,
2-50.


20
6
0.57


Lot 9-
Arse-
nate of
Lsad,
3-50.

5
13
2


20
6
0.24


/


Lot o10-
Arse-
nate of
lead,


12






S





20
4
0.02


Larvae dying in each lot.


I ---- --- ---
Lot 11- Lot 12- Lot 13- Lot 14- Lot 15-
Date ofeami i. Lime- Lime- Lime- Lime- Arsenate
Date of examination, sulphur, sulphur, sulphur, sulphur, oflead,
1-50; 10; 50; 1-50; 1IL50; 2-50;
arsenate arsenate arsenate arsenate lime-
of lead, of lead, of lead, of lead, sulphur,
J-50. 1-50. 2-50. 5-50. i-50.


A ug. 21 ............. .... ................ 3 10 9
23 .............. 2 14 9 10 9
25 .............. 8 4 7 ........ 2
27............... 6 21 .......... ..........
29 ............... 4 ....... .......... .......... .........
3 1 .............. .......... .... ..... ... ..... .. ....... I ........
Sept. 2 .......... ...................... ........... .......... ....
4 .............. .......... .. ........ .. .... .. ... .. ..... .....
,,.. .. .......... ........ ............... ..... .... ....................
o ,,.. :................ .................... .
10 .... .... I ... .. ..I.. .... .. ..
Oct. 3........... ... ..... I ... ...... .......... .......... ..........


Total number
dead .........
Number days re- I
quired to kill.......
Square inches of foli-i
age consumed......


I___ I ________
20 1 20 20 20 20
1
10 8 8 4 6
0.52 0.02 0.28 0.07 0.30


Lot 16-
Arsenate
of lead,
2-50;
lime-
sulphur,
9-50.


5
11
4










20
6
0.19


Lot 17-
Arsenate
of Lead,
2-50;
lime-
sulphur,
1-50.


1
6
13










20
6
0.06


Lot 18-
Arsenato
oflead,
2-50;
lime-
sulphur,
3-W0.


6






.. .. .....





20
6
..... 2.
.o........
.. ........



20
6
0.22


None of the larvae on the unsprayed lot died until September 15,
27 days after the experiment was started. On October 3 the records
of this lot showed 8 dead, 6 pupated, and 6 missing. Lime-sulphur

alone, -50, and likewise 1-50, killed all the larvae in 12 days, while
the time required by strengths of 1A-50 and 3-50 was 8 days in each
case, the rapidity of killing being somewhat greater with the latter

strength. Arsenate of lead alone, 4-50, killed the 20 larvae in 10 days,

or 2 days more than was required by lime-sulphur, 1I-50. Arsenate


i


.1 :


I





LIME-SULPHUR A STOMACH POISON FOR INSECTS. 87

of lead, 1-50, 2-50, and 3-50, each killed the larvae 2 days sooner than
that required by lime-sulphur, 14-50. Lime-sulphur, 14-50, when
added to the various strengths of arsenate of lead did not appreciably
affect the rate of killing of the arsenate of lead. The amount of feed-
ing was reduced in all cases, excepting that of the strongest solution,
lot 14, by the addition of lime-sulphur.
On the lots sprayed with lime-sulphur, 1-50, 3-50, 1 4-50, and 3-50,
combined with arsenate of lead, 2-50, there was no difference in the
length of time required to kill the larvae, 6 days being required in all
cases. The same number of days was required by arsenate of lead
alone, 2-50, but the rapidity of killing was somewhat increased by the
addition of lime-sulphur.
EXPERIMENT V.

In an experiment to obtain data on the sticking qualities of various
sprays, three lots of the regular orchard demonstration strength of
lime-sulphur, 1-50, were used. The three lots were thoroughly
sprayed and allowed to dry. One lot was then washed for 15 minutes
under a shower bath, by placing the twig just above the floor in an
inclined position, allowing the water to fall upon it. Another lot was
washed 30 minutes in the same manner, while the third lot remained
unwashed.
The same procedure was carried out on three lots of arsenate of
lead, 2-50. After the twigs were again thoroughly dry 20 larvae were
placed on each. The results of this experiment are to be found in
Table V.

TABLE V.-Tests of the killing effect of lime-sulphur in comparison with arsenate of lead
after washing oJ each.
[Experiment started August 4,1912, Benton Harbor, Mich., 20 larvae in each lot.]

Larvae dying in each lot.

Lot 2- Lot 3- Lot 4- Lot 5- Lot 6- Lot 7-
Date of examination. Lot 1- Lime- Lime- Lime- Arsenate Arsenate Arsenate
Check sulphur, sulphur, sulphur, of lead, of lead, of lead,
(un- 14-50; lU-50; 14-50; 2-50; 2-50; 2-50;
sprayed), not washed 15 washed 30 not washed 15 washed 30
washed, minutes, minutes, washed, minutes, minutes.

Agg. 7 ........................... ...... ..... .... ..........................................
9............... .. ..... ...................... ................. ... .......... 7 2 ..........
11 ................................... 2 .......... 1 12 4 ...
13 .................................. 2 2 2 .......... 5
15........................ .......... 12 9 8 .......... 9 '
17............. .................. 1 4 7 9 .................... 7
19.............................. .......... 2 ............. .......... 4
21........................ ...... .................................................. 4
29......................... 2 .......... .......... ........... ... ....... .......... .....
Sept. 9...... ............. ... 3 ........ .. ......... .. ................ ...... ........ ..
19 ......................... ... .................. ..............................
Total number of dead .... 7 20 20 20 20 20 18
Number of days required to kill. ........... 13 15 13 7 11 17
Square Inches of foliage con-
sumed........................ 111.0 0.S2 1.56 0.84 0.38 1.79 5.00

12 escaped.




88 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. I

The washing made practically no difference in the killing effeeAt 'iI
the lime-sulphur spray, the time of killing varying froj4 I.zt:j, iba I'
and the amount of foliage consumed varying from 0.82 to 1.56' Nsfe.;
inches. In the case of arsenate of lead, however, the killing effect w |
considerably retarded. The length of time required to kill all the:
larvae when the foliage was unwashed was 7 days; when washed 18IA
minutes, 11 days; when washed 30 minutes, 17 days. The amount
of feeding was 0.38, 1.79, and 5 square inches, respectively. .

EXPERIMENT VI.

To compare the killing effect of commercial lime-sulphur and home '
boiled lime-sulphur, an experiment was conducted in which two lotw I
of each kind were used at the strength of 11-50. The commetildS
products tested 339 Baum6 and the home-boiled 30 Baum6. 7 i.
results are shown in Table VI.

TABLE VI.-Tests of the killing effect on the fall webworm of lime-sulphur, commercab
and home-boiled. "
IExperiment started Aug. 27, 1912, Benton Hlarbor. Mich., 20 larvae in each lot.]

Larvae dying in each lot.

Date of examination. Lot 1 Lot 2 Lot3 Lot4 Lot 2
(20 larvae)- (20 larve)- (2rlarv()- 2larvse)-
(20 larve)- ('n Commercial Commercial Ho ed me-boiled Hom-boled
rCheck (un- lime-sulphur, lime-sulphur, lime-sulphur, lime-sulnhurj
sprayed). 1-50. 12L-50. 4-50. I .

Aug. 30 ......................... .... .... .... ... . . . .. - --- A
Sept. 1.......................... .. ......... ... 6 4 3 5
4 .......................... ............. 7 9 7 6
6 ........................................ 7 6 6 W
9 ......................... ............. .............. 1 3 ..............
19....................... .. 1 ..... ... ..... ....... .
O ct. 1.9 ......................... 5 .-.-.. .... ---- ---- --- -------.-..---..---.. .. .. .. ..
Total number dead 6 20 20 20 20
Number of days required to kill ...... 9 12 12 9
Square inches of foliage consumed. 116.00 1.19 1.28 3.05 4.38

It was found that the commercial and the home-boiled lime-sulphur
killed all the larvae in the same average length of time. However, the
rapidity of killing was slightly greater, and the amount of foliage. ,
consumed less, where the commercial material was used, due probably
to the fact that the commercial solution was somewhat stronger, whieti
the Baum6 tests would indicate.

EXPERIMENT VII. i

Lime-sulphur, 1 -50, was tried out on a limited number of pei& "
slug larvae (Eriocampoides cerasi L.), since only a few were available i
for this test. As in all the experiments, the insects were not plitmu o
upon the leaves until the spray had thoroughly dried. The resh k
are shown in Table VII.



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LIME-SULPHUR A STOMACH POISON FOR INSECTS. 89

TABLE VII.-Tests of the killing effect of lime-sulphur on the pear slug (Eriocampoides
cerasi L.).
[Experiment started Aug. 24,1912, Benton Harbor, Mich., 6 larvae in each lot.]

Larvam dying in each lot.
Date of examination. Lot 1 (6 Lot 2 (6 Lot 3 (6
larvwe)-Check larva)-Lime- larv;r)-Limne-
(unsprayed). sulphur, lj-50. sulphur, l.--50.

A ug. 25.................. ............ 3 ........... .
26 ................... ... .... ......... 2 4
27 .. ... .......... .. ... 1 2
28 ... ............. ..... ... .. ... .. ..... .. .... ..... ...
29 .. ............... .. ..... ... ... .
Total number dead... 0 6 6
Number of days required to
kill... . 3 3
Square inches of foliage
consumed .............. 1.69 0.08 0.05

Three days were required to kill all the larvae on the sprayed lots.
At the end of five days, when the experiment was closed, the larvae
on the unsprayed lot were apparently in a normal condition.

MISCELLANEOUS TESTS.

Preparations were made to conduct a number of feeding experi-
ments on the killing effect of lime-sulphur on the second brood of
codling-moth larvae (Carpocapsa pomonellUa L.). But since a suffi-
cient number of larvae was not obtainable, owing to the small size of
this brood appearing in Michigan, no satisfactory tests could be
made. Neither were there any tests withl lime-sulphur alone made
against this insect in the field. However, in the case of a plat of
Ben Davis apples, sprayed three times with lime-sulphur, 1-50, and
10 per cent kerosene emulsion, no arsenical being used, the total
percentage of windfalls and picked fruit free from the codling moth
was 90.18, as against 41.31 per cent of fruit free from this insect on
the unsprayed plat. Lime-sulphur, 1-50, and fish-oil soap, 7 pounds
to 50, without an arsenical, in the same orchard held the codling
.moth to 88.19 per cent of sound fruit. The effectiveness of lime-
sulphur alone in controlling the codling moth and numerous other
insects will be further tested during the season of 1913.
A few laboratory tests were made of the killing effect of Bordeaux
mixture, 3-4-50, on the fall webworm and about as effective results
were obtained as from lime-sulphur solutions.
Self-boiled lime-sulphur, 8-8-50, the preparation used for spraying
peaches in foliage, was tried against the fall webworm without any
killing effect. Sulphur alone, 8-50, and lime alone, 8-50, likewise
were ineffective.





DECIDUOUS FRUIT INSECTS AND INSECTICIDES.


CONCLUSIONS. 1

The foregoing tests of lime-sulphur wash against the larvae of the
fall webworm show that this preparation has decided value as a
stomach poison. It is considered extremely probable that cater-
pillars of many species of insects, and perhaps mandibulate insects
in general, will be similarly susceptible. As shown by the data given,
lime-sulphur, 1-50, while slower in killing effect than arsenate of
lead, 2-50, nevertheless compares favorably with this strength of
arsenical. A comparison, however, of leaf-areas eaten by larva
subjected to lime-sulphur and arsenate of lead, respectively, shows
that the lime-sulphur, especially at increased strengths, compares
quite favorably with the arsenical in reducing feeding by the cater-
pillars.
This action of lime-sulphur as a stomach poison probably accounts
for the reported practical control of the codling moth in orchards
treated with lime-sulphur alone, and furnishes an additional reason
for its employment as a fungicide.
Experiments in progress by the Bureau of Entomology during the
past two years warrant the statement that entirely satisfactory
results in controlling the codling moth in orchards may be obtained
with lime-sulphur wash combined with reduced strengths of arsenate
of lead.







*



ADDITIONAL COPIES of this publication
may be procured from the SUPr nnwnn-
aT or DocuxzMNs, Government Printing
Office, Washington, D. C., at 5 cta -per copy


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