28 ASSOCIATION" OF ECONOMIC ENTOMOLOGISTS. 



as a means of control, and to test the value of these poisons some 

 experiments were made, as follows: 



A young poplar in a nursery row was headed back and sprayed 

 with poison; a bag of mosquito netting was then put over the tree 

 to inclose some beetles. As a check to each tree treated in this way, 

 beetles were confined in a similar manner as mentioned above upon 

 trees that had not been sprayed. With one exception this work was 

 done upon nursery poplars that were 2 to 4 years old. 



It is not necessary to give the data in detail, but it is sufficient to 

 say that the results of a number of experiments made during the fall 

 of 1905 indicated strongly the possibility of using arsenical sprays 

 as a remedy. When beetles were confined upon trees sprayed with 

 poison they died in a few days, while beetles confined in a similar 

 manner upon unsprayed trees continued to feed and to oviposit. 



In order to corroborate these results the work was continued during 

 1906. In addition, an effort was made to determine the length of 

 time that the spray was effective and whether or not the poison 

 acted as a repellent. The" experiments were conducted in the same 

 manner as in the previous year and the results were even more con- 

 clusive. The poison was found to be effective for thirty days, and 

 by close observation it was found that the beetles, when feeding, 

 failed to discriminate between sprayed and unsprayed bark. 



While the experiments were conducted according to laboratory 

 methods and the number of beetles involved was limited to about 

 three hundred, the results are encouraging and indicate that thorough 

 spraying of poplar plantations with an arsenical poison materially 

 reduced the number of beetles and thereby lessened the number of 

 eggs deposited in the trees. 



Experiments are now under way in commercial poplar blocks to 

 determine the value of this treatment. From the work that has been 

 accomplished it is estimated that an application of an arsenical poison 

 to nursery poplars will cost about one-fourth of a cent per tree for 

 labor and poison. 



Mr. J. B. Smith stated that this insect was not a nursery pest, 

 although it was present in New Jersey. 



In reply to a question, Mr. Parrott said that the insect was found 

 in western New York. 



Mr. Slingerland related a case which had come under his observa- 

 tion where infested trees had been treated with pure kerosene and the 

 borers had been destroyed. 



Mr. Washburn remarked that nursery trees from Xew York badly 

 infested with this insect had been shipped into Minnesota, and he 



