New Yoke: Agricultural Experiment Station. 385 



SPRAYING EXPERIMENTS AGAINST THE SPRING 



CANESR 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 larva? 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 lime 

 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 pi\ mptly as' Paris green, as they are cheaper (page 388) 

 and can be applied more evenly, and hence, if equally efficacious, 

 are more sr isfactory. . - 



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 apple 

 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 



