MISCELLANEOUS INSECTICIDE INVESTIGATIONS. 
21 
Experiment XII. 
COxMBINED SPRAYS AGAINST LARY.K OF THE FALL WEDWORM. 
The purpose of Experiment XII was to test by the laboratory 
method certain spray combinations, some of which were being used 
under field conditions. The arsenate of calcium used in this experi- 
ment was prepared by using 4 pounds of stone lime, to which was 
added 18 ounces of sodium-arsenate crystals during the slaking. 
This, when mixed with the proper quantity of water, was used for 
the making of Bordeaux mixture 4-4-50. This combination was 
made with a view to using it as a vineyard spray. The results of 
this experiment appear in Table XII. 
Table XII. — Tests of the killing effect of various materials on the fall webworm. 
[Experiment started July 24, 1914, Benton Harbor, Mich.; 10 larvae in each lot.] 
Name and dilution. 
Dates of exami- 
nation and num- 
-c 
ber of larvae 
a 
c? 
dying in each lot. 
"0 
v. ZS 
$ 
5?a 
July. 
August. 
fa 
3 
*3 
S 
29 
1 
1 
13 
o 
3 
1 
10 
10 
8 
14 
5 
4 
7 
3 
4 
10 
10 
8 
20 
2 
3 
1 
n 
3 

10 
10 
8 
20 
4 
5 
1 
3 
6 
1 
10 
14 
8 
2 
10 
10 
8 
8 
5 
1 
1 


2 
Arsenate of lead powder, 1.^-50+ lime-sulphur, 1^—50 
Lime-sulphur, 1^-50 
Arsenate of lead powder, l£-s30 
Commercial sodium sulphid, 2-50 
Commercialsodiumsulphid,2-50+arsenateof lead powder,l£-50 
Commercial barium tetrasulphid, 5-50 
Commercial barium tetrasulphid, 5-^50+ arsenate of lead pow- 
der, l£-o0 
Sodium arsenate (crystals, tech. pure), 18 ounces+ Bordeaux 
mixture, 4-4-50 
Sodium arsenate (crystals, tech. pure), 18 ounces-!- Bordeaux 
mixture, 4-4-50+ nicotine sulphate, 40 per cent, 1-1,600 
Check (unsprayed) 
0.18 
0.82 
0.46 
3.34 
0.22 
5.76 
0.34 
0.10 
0.10 
13.50 
As will be noted in Table XII, arsenate of lead, either alone or com- 
bined with lime-sulphur solution or commercial sodium sulphid, 
killed all the larvae in 8 days. The same arsenical combined with 
commercial barium tetrasulphid compound required 14 days to kill 
the 10 larvae, although 9 of these were recorded dead at the end of 
the eighth day. The arsenate of calcium made hi the same operation 
of slaking the stone lime for Bordeaux mixture caused the death of 
all the larvae in 9 days. This combination was tested in a vineyard 
and caused no foliage injury. At the end of 20 days, when the experi- 
ment was closed, but two larvae of the unsprayed lot were dead. 
