232 



Bulletin 176. 



Raupenleirrh. — This " Caterpillar glue " is a Greriiian product, 

 resembling somewhat axle grease mixed with tar. It has been 

 extensively used in Europe, and in fighting the Gypsy Moth in 

 Massachusetts. It is sticky and has a distinct tarry odor, and is 

 applied to the bark of trees to prevent the ascent of caterpillars and 

 other insects. When applied in a thick band, it retains its sticky 

 properties for a considerable period. Apparently it had the neces- 

 sary qualities to make it a good preventive wash to keep out peach- 

 tree borers, hence we tried it for two years with the following 



results : 



1895-1896. 



When applied. 



June 18, 1895 



July 10, 1896. 



Numbei- 

 of trees 

 treated. 



When examined. 



21 



42- 



June 11, 1896 



Number 

 of trees 

 infested. 



Number 



of borers 



found. 



Efifect of applica- 

 tion on tree. 



1896-1897. 



June 22, 23, 2o, 

 28, 1897 



Killed 7 recent- 

 ly-set trees. 



Killed every 

 tree. 



It is to be noted that the first year the raupenleim apparently 

 injured only seven trees which had been set only two or three 

 months and had not yet become thoroughly established. As a pre- 

 ventive against the peach-tree borer it was a perfect success on the 

 14 uninjured trees. Our hopes rose high, and we treated twice as 

 many trees the second year, but we were doomed to bitter disap- 

 pointment for, as the table shows, not a tree survived the treatment. 

 In figure 56 is shown the effects of raupenleim and dendrolene. 

 Perhaps old trees will stand the raupenleim bettei", but we believe 

 it is not a safe, although apparently a sure, preventive wash. 



We applied the raupenleim on the bark from the roots to about 

 six or eight inches above the surface of the soil; \ pound sufficed 

 to treat 21 trees (1-|- to 2 inches in diameter), making a band of the 

 substance from \\,o \oi an inch thick. 



Dendrolene. — This is a crude petroleum product and an American 

 imitation of the German raupenleim. The substance was first made 

 for Professor Smith in New Jersey in 1 895, and some preliminary 



