MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 
13 
Table VI. — Tests of the killing effect on the tent caterpillar of arsenate of calcium, alone 
and combined with lime-sulphur, in comparison with arsenate of lead. 
[Experiment started May 17, 1913, Benton Harbor, Mich.; 50 larvae in each lot.] 
Larvae dying in each lot. 
Check 
(un- 
sprayed). 
Arsenate of lead, 
2 to 50. 
Arsenate of cal- 
cium (home- 
made, l),0.Slb. 
to 50. 
Arsenate of cal- 
cium (home- 
made. 2), 0.81b. 
to 50. 
Arsenate of cal- 
cium (com- 
mercial paste), 
1 J to 50. 
Dates of examination. 
6 
8 
<5 
> 
d 
a 
<5 
c 
o 
< 
3 
— 
ad 
1 
© 
3 
O 
3 
3 
■a 
|| 
O 
O 
CO 
o 
o 
IQ 
O 
to 
o 
S 
00 
o 
OS 
"o 
-3 
d 
O 
o 
Hi 
CO 
o 
Hi 
t" 
O 
h! 
Mav 20 
1 1 
2 1 
1 

4 2 
42 
8 
45 
5 
16 
27 
7 
36 
12 
2 
38 
12 
27 
23 
30 
18 
2 
33 20 
35 
15 
43 
7 
28 
May 22. .. 
17 
20 
10 
18 
May 24. 
4 
May 31... 
50 
5 
0.04 
50 
5 
0.04 
50 
7 
0.01 
50 
7 
0.05 
50 
5 
0.02 
50 
7 
0.04 
50 
5 
0.06 
50 
5 
0.05 
Total number dead 
Days required to kill 
50 
5 
0.06 
50 
50 
50 
7 
Square inches foliage con- 
8.10 R- 75 
0.06 
0.02 
0.03 
Arsenate of calcium, commercial (paste), used at the rate of 1J 
pounds to 50 gallons killed all the larvae in 5 days with 0.05 and 
0.06 square inch of foliage consumed. The same preparation com- 
bined with lime-sulphur killed in 7 days with 0.03 square inch of 
foliage consumed. 
It will be noted that when lime-sulphur was used with the poison, 
less foliage was consumed. 
Experiment VII. 
LEAD CHROMATE VERSUS ARSENATE OF LEAD AGAINST THE LARV.E OF FOUR SPECIES 
OF INSECTS. 
Experiments were conducted with lead chromate, commercial and 
homemade, used at various strengths in comparison with arsenate of 
lead used at the rate of 2 pounds to 50 gallons of water, against four 
species of insects, Eriocampoides cerasi Peck, Ili/phantria cunea, 
Ilalisidota caryae Harris, and Datana ministra Drury. The results of 
these experiments are given in Table VII. 
Neither the commercial nor homemade lead chromate was very 
effective against the pear slug (Eriocampoides cerasi), 6 larvae living 
through to pupation in each case, and almost as much foliage was 
consumed as on one of the checks. Arsenate of lead killed 8 of the 
larvae in 3 days. The other 2 larvae escaped. Nine of the larvae 
pupated in each of the two unsprayed lots. 
