New York AGRICULTURAL Experiment Sration. 387 
fesulis.— The results were practically uniform on the two plats. 
Decided results were apparent after the second application. The 
treated trees were practically freed from caterpillars by the 2 
applications. The third application only ensured a little more 
thorough work. As in the previous year the check trees were 
stripped of their foliage. 
DISCUSSIONS OF RESULTS AND THE ARSENICALS USED. 
The results indicate that any one of the three insecticides can 
be depended upon to kill canker worms if properly handled, and 
that green arsenite and arsenite of lime are equally efficacious with 
Paris green as poisons for tfis insect. In these experiments much 
pains was taken to keep the mixtures well agitated, in order to 
keep the poison well distributed in the tank and to make the ap- 
plications thorough. Keeping the mixture well agitated is of 
especial importance when Paris green is used, as it settles quickly. 
As the arsenicals give practically even results and the foliage 
was not injured in any case, the principal points to be considered 
are the ease of application and the cost per pound of the poison. 
These points may be brought out more clearly by a brief discus- 
sion of each arsenical. 
Paris green.— The retail price of Paris green is usually from 
25 to 30 cents per pound. It can be bought in wholesale lots, 
50 pounds or more, for about 18 cents per pound. The prin- 
cipal difficulty in using Paris green lies in the fact that it settles 
so quickly to the bottom of the tank and is so heavy that it is 
dificult to keep it evenly distributed throughout the tank while 
spraying. ‘The usual result is that most of the poison is pumped 
out before the water is half gone. Thus the poison is applied 
very unevenly. 
Green arsenite.— This arsenical has been previously discussed.”® 
It costs, retail, 15 cents per pound and can be obtained cheaper in 
wholesale lots. It is manufactured by the Adler Color and Chemi- 

18 Page 340 of this Report. 
