New Yorx AaricutturaAL Experiment Srarion. 385 
SPRAYING EXPERIMENTS AGAINST THE SPRING 
CANKER WORM. 
There are two principal methods of combating this insect in 
general use. ‘The first is directed against the insect in the adult 
stage and consists of placing mechanical obstructions or traps | 
about the trunks of the trees to prevent the females, which are 
wingless, from ascending the tree to deposit their eggs upon the 
twigs. The second is directed against the larvee and consists of 
spraying with an arsenical poison. Although good results have 
been obtained by the former method it has been pretty clearly 
demonstrated that it cannot be depended upon to entirely rid an 
orchard of this pest. Spraying is, therefore, of much importance 
as the other principal method of checking the insect. 
EXPERIMENTS. 
Objects of the experiments.— The principal objects of the ex- 
periments were to compare green arsenite and arsenite of hme 
with Paris green as poisons for the canker worm, and incidentally 
to again demonstrate that pure Paris green itself, properly 
handled, can be depended upon as a remedy. It is important to 
know definitely whether these newer poisons can be depended upon 
to act as promptly as Paris green, as they are cheaper (page 388) 
and can be applied more evenly, and hence, if equally efficacious, 
are more satisfactory. 
These experiments were conducted in the orchard of Mr. O. L. 
Jackson of Rushville, N. Y., to whom the writer is indebted for 
much assistance in the work of spraying the trees. The orchard 
is a large one, thrifty, and consists principally of Baldwin ape 
- trees from 25 to 30 years old. 
Experiments in 1897.— About one-third of the orchard was 
badly infested. Only the worst infested trees were selected for 
the experiments, which were as follows: 
25 
