i6 



Experiments in 1896. — As shown in the table, the plats were 

 sprayed but twice in 1896. Unfavorable weather prevented a 

 third spraying until too late to be practicable and the machines for 

 catching the beetles were used twice, about seven days apart, after 

 the last spraying. For these experiments a knapsack sprayer was 

 used to apply the poison. When lime was used, enough of the 

 freshly slaked lime was added to make the mixture slightly milky 

 in appearance. 



Results in i8g6. — It was difl&cult to obtain exact results in 

 this case. Swarms of beetles came from other fields to the 

 sprayed plats. The general indications were that the plats 

 sprayed with green arsenite mixed with lime water and glue and 

 and with arsenate of lead and glue were less injured after the 

 second spraying than the other plats. About 80 per ct. of the 

 willows on these plats were uninjured by the beetles, while on 

 Plat III, the check plat, at least 50 per ct. were damaged. 

 Glucose did not prove as successful in making the mixture adhere 

 to the leaves as thin glue, but glue was found to be impractical 

 for this purpose because of sticking in the pump and clogging 

 the nozzle. 



Experiments in i8gy. — The plan of the experimental field was 

 changed for these experiments and a Peppier horse-power sprayer 

 used in place of a knapsack. As shown by the diagram the 

 acre was divided into two equal plats and both plats sprayed on 

 June 3.' The machine for catching the insects was not used on 

 either plat. Plat II received but one application of the poison 

 while Plat I was sprayed as shown in the following diagram. 



The green arsenite was used at the strength of i lb. to 100 

 gallons of lime-water. Whale oil soap, i lb. to 20 gallons 

 of the mixture, was added to make it spread upon the leaves. 

 Whale oil soap also doubtless acts as a repellent to the insects 

 and may be used much stronger. 



"The original plan was to leave Plat II unsprayed but through a misunder- 

 standing it received one application of the poison. 



