V. EXPERIMENTS WITH DENDROLENE. 



Early in Ai)ril, ISOG, the P.owker Fertilizer Company of Boston, 

 Mass., sent a 20-poun{l pail of dendrolene to the Station for trial. 

 Dendroleue, it is stated by the jaaniifactnrers, is " a new sub- 

 stance for tree protection " and is briefly described by them as 

 follows: '' It is a thick, plastic combination of about the constitu- 

 ency of printer's ink; but, unlike printer's ink, it will retain its 

 ' stickiness ' under almost all conditions of climate or tempera- 

 ture, and when spread with a trowel or stiff brush around the 

 trunk of a tree in a thick band, forms a soft, sticky bed." This 

 new insecticide was originated in New Jersey. 



In addition to the twenty pounds sent, the Station bought fifty 

 pounds more, a considerable portion of which was used in the 

 experiments. 



As above indicated, dendrolene is intended to be used chiefly 

 on the trunks and branches of trees and thus to serve two prin- 

 cipal purposes: First, to prevent such insects as the female 

 canker worm moth from crawling up the trunks of trees. Sec- 

 ond, to prevent borers from escaping from infested trees and the 

 parent insects from depositing eggs on the trunk or at the crown 

 of the root. When used for the first-named purpose, it should 

 be put in a band around the trunk of the tree and when used 

 for the latter, should cover the entire trunk. 



Objects of the Experiments. 

 The experiments were made with the purpose of testing the 

 dendrolene along the lines above mentioned, and also to ascer- 

 tain if the trees were liable to injury from its use. 



Experiment No. 1. 

 April 16, twelve large Baldwin apple trees were treated, the 

 dendrolene being applied in rings about one and one-half feet 

 wide about the trunk midway between the ground and the lower 

 limbs. In this and the following experiment, the trunks were 

 scraped before applying the dendrolene. 



