E 



be 



, 



The tests made in 1905 and their results were as 

 Tests follows: (1) Of three pairs of beetles confined 

 with by mosquito netting on the branch of a poplar 



poison. tree that had been sprayed with paris green, 

 all died within 6 days. (2) Eight pairs of beetles 

 were confined on each of two poplar trees in a nursery row, the 

 tops of the trees having been headed in and sprayed with arsenate 

 of lead. In 6 days, twenty of the thirty-two beetles were 

 dead, and there was only a little puncturing of the bark. (3) 

 Forty beetles were similarly confined on two trees that had been 

 sprayed twenty days before with arsenate of lead. Though 

 much of the poison had apparently washed off, all but one of the 

 40 beetles died within three weeks. (4) As a check upon these 



periments, 26 beetles were confined on several unsprayed trees, 

 it was thought that possibly confinement might destroy the 

 eetles. All but three of these insects were alive at the end of 

 nr weeks and the bark of each tree was badly punctured. 



Similar tests made in 1906 resulted in the death, within two 

 weeks, of forty beetles confined on trees sprayed some time pre- 

 viously; while only four beetles out of twenty confined on an 

 unsprayed tree died in that time. 



It was unmistakably the poison and not the confinement that 

 killed the beetles. But it was barely possible that if not con- 

 fined the beetles would avoid the poison and seek unsprayed 

 trees; so a test was made to cover this point also. Fifteen beetles 

 were placed in each of three glass jars, w r ith an abundance of 

 food in each. In the first jar all the twigs were sprayed with 

 poison, in the second only half were sprayed and in the third 

 none were sprayed. The beetles in the second jar evidently did 

 not avoid the poison; for all but one died within a week, as was 

 the case with those in the first jar. In the jar containing un- 

 sprayed twigs thirteen of the fifteen beetles were alive at the end 

 of the week. 



From these tests it seems quite conclusively proven (1) that a 

 poison spray mixture remains for some considerable time on 

 nursery poplar trees, (2) that the beetles feed readily on such 

 poisoned trees and (3) that the poison is quite effective against 

 the insects. 



Other tests and observations show that the beetles do not 

 travel far nor leave an abundant supply of food. None have ever 



