October, ’20] 
PETERSON: ORIENTAL PEACH MOTH 
397 
Table III.—The Effect of Lead Arsenate (Liquid and Dust Mixtures) on Larvae of Known 
Size. The Spray and Dust Mixtures Thoroughly Coating the Entire Surface of 
Immature Peaches 
Experiment 
number 
Liquid sprays and dusts 
2-4 mm. larvae 
5-6 mm. larvae 
7-9 mm. larvae 
Total larvae 
Entered 
Dead 
Entered 
Dead 
Entered 
Dead 
Entered 
Dead 
40 
Lead arsenate, 2 lbs.-50 
gals., plus casein-lime, 
2 lbs.-50 gals. 
8 
5 
48 
1 
29 
0 
85 
6 
41 
Lead arsenate, 4 lbs.-oO 
gals, plus casein-lime, 
2 lbs.-50 gals. 
8 
3 
39 
3 
27 
0 
74 
6 
42 
Lead arsenate, 1 pt.-lime 
5 pts. (dust) 
0 
8 
17 
28 
44 
1 
61 
37 
43 
Lead arsenate, 1 pt.-sul- 
fur 1 pt. (dust) 
0 
15 
8 
38 
42 
18 
50 
71 
44 
Hydrated lime (dust) 
6 
4 
22 
14 
39 
0 
67 
18 
45 
Check 
13 
0 
29 
0 
32 
0 
74 
0 
material to stick. Dusts adhere better than liquid sprays due to the 
fact that a growing peach shoot has a somewhat sticky surface. The 
surface of a peach is pubescent, consequently liquid sprays and dusts 
readily cling to its surface. Again it is probable that a larva entering 
a thoroughly dusted fruit is more apt to consume some of the poison 
than a larva entering a twig. 
In addition to the above experiments with peach twigs and fruit a 
number of immature apples were dusted and sprayed with various 
lead arsenate mixtures (as given in Table III). In no case did the 
poison prevent the larvae from entering the fruit. The larvae used in 
these experiments were at least half grown and larger. 
Dr. P. Garman suggested the spraying of infested twigs with arsen¬ 
ical poisons with the hope of killing the worm as it ate its way out of the 
twig. The larva usually eats its way out of the twig near the terminal 
end of its interior channel. This may be several inches from the point 
of entrance. Fifty twigs were collected which seemed to possess liv¬ 
ing larvae. Twenty-five of these were thoroughly sprayed with lead 
arsenate at the rate of 4 pounds to 50 gallons of water with the addition 
of casein-lime, 2 pounds to 50 gallons of spray and the other twenty- 
five twigs served as a check. Ten days after the experiments were 
started the cloth cages in which the experiments were enclosed were 
examined. The check showed sixteen larvae alive on the walls of the 
cage or pupating in cocoons and one dead, while the sprayed lot 
showed fourteen larvae alive on the walls of the cage or pupating and 
two dead. This experiment was repeated and similar results were 
