386 Report of the Entomologists of the 



Plat I consisted of about 100 trees. Paris green was applied 3 

 times at the strength of 1 pound to 150 gallons of lime water. The 

 first application was made as soon as the young caterpillars ap- 

 peared, which was about May 6. The second application was made 

 a week later and the third about 4 days from that time. 



Plat II consisted of 14 trees and was sprayed with green arsenite, 

 1 pound to 150 gallons of lime water. The first application was 

 made May 18, the second May 22 and the third June 1. 



Plat III consisted of 3 badly infested trees and was left 

 untouched as a check. The lime was not measured in any of the 

 experiments, but enough freshly slaked lime was used to make 

 the mixtures slightly milky in appearance. 



Results. — ~No very decided results were noticeable on either plat 

 until after the second application, except in the case of the smaller 

 caterpillars, those about one-fourth of an inch long, which suc- 

 cumbed readily. Four days after the second application but very 

 few live caterpillars could be found. The results were practically 

 the same on the two plats. Probably the third application was 

 hardly necessary. On Plat III the trees were nearly stripped of 

 their foliage by June 1. 



Experiments in 1898. — This year the orchard was not as badly 

 infested as in 1897. As in the year previous the worst infested 

 trees were selected and divided into plats. 



Plat I, consisting of about 40 trees, had two applications of 

 green arsenite at the same strength as in 1897. The caterpillars 

 did not appear as early as the year previous, and hence the first 

 application was not made until about the middle of May and the 

 second about a week later. 



Plat II was sprayed 3 times with arsenite of lime made 

 after the Kedzie formula. 17 The first application was made May 

 27, the second May 31, and the third June 10. Plat III con- 

 sisted of 2 trees, which were left unsprayed as a check. 



17 See note at the foot of page 388. 



