1907.] PUBLIC DOCUMENT — No. 33. 179 



motli egg clusters. In one instance, where creosote and naph- 

 tha were applied with an atomizer to the trunks of trees cov- 

 ered with gypsy caterpillars, at the rate of 1 part of creosote 

 and 5 parts of naphtha, the bark was rendered brittle and life- 

 less. At the time our examinations were made on these trees 

 no injury had occurred to the cambium layer, but we should 

 suspect that injury would later follow this method of treat- 

 ment. 



Some injury to trees often occurs from the use of kerosene, 

 or kerosene and water together, when applied to the bark of 

 trees. Kerosene and water have occasionally been applied to 

 tree trunks for various insect pests by the aid of a certain 

 mechanical mixing device. Tt should be stated, however, that 

 these mechanical mixers are unreliable, and it is never safe to 

 apply kerosene to trees, not even when mixed with water. 

 The use of a gasoline blower or torch for the purpose of kill- 

 ing caterpillars has been in vogue to some extent. This 

 should be condemned, since some injury has resulted from 

 this practice. Scraping the bark too closely previous to apply- 

 ing a banding substance should be guarded against. 



In conclusion, it may be said that Tanglefoot appears to be 

 the only banding substance which we have tested that does 

 not in any way cause injury to plant tissue, and that can be 

 safely applied directly to tree trunks. Since this substance 

 has a tendency to run at about 125° to 130° F., a slightly 

 higher melting point would improve it. The manufacturers 

 test this substance at 126° F., on a smooth, vertical surface, 

 claiming that it will not run below that temperature; also, 

 that some of their samples will not run below 130° F. They 

 state that it will stand a little higher temperature on the bark 

 of trees before it begins to run. Unfortunately, much of the 

 Tanglefoot sent out by the manufacturers last spring was made 

 on a different formula, and the melting point was entirely too 

 low. It was sent back to the manufacturers, and modified 

 according to a previous formula. 



Such material as printer's ink, Bodlime, etc., can be safely 

 applied to tree trunks in connection with tarred paper; and 

 the latter can also be applied to rough, thick-bark trees without 

 killing them, although even when used in this manner it will 



