31 

 Mr. Smith read the following paper: 



"RAUPENLEIM" AND "DENDEOLENE." 



By John B. Smith, New Brunswick, N. J. 



[Author's abstract.*] 



'' Raiipenleim '^ and '* dendrolene " are both crude petroleum products 

 of a butter-like consistency at ordinary temperatures, and becoming 

 oidy slightly softer at high temperatures. The raupenteim is a Ger- 

 man product, very dark in color, with a tarry odor and probably mixed 

 with some tar prei)aration. The Ameri(?an product is brown in color, 

 almost without odor, and without foreign admixture to disguise its 

 character or give it a specific smell, liaupenleim is largely used m 

 Germany to protect trees from the attacks of certain insects and to 

 prevent their being injured by stock or deer during the winter. The 

 materials were tested comparatively for the purpose of preventing 

 borers from attacking fruit trees, and if possible to prevent their issu- 

 ance when already under the bark. Both materials can be readily 

 applied with a paddle or trowel and distributed by means of a stiii' 

 brush so as to make a tolerably even coating. Experiments showed 

 that it did not injure even young shoots where applied to the bark only; 

 but where buds or growing tissue were covered it killed the buds and 

 shoots by choking the stomata. A young tree set out in 1894 was cov- 

 ered from the surface of the ground to the buds without detracting from 

 its vigor during the balance of the season. It was applied upon an 

 orchard of pear trees infested by the sinnate pear borer and both mate- 

 rials prevented ovi])osition. The raupenleim absolutely ])revented the 

 issuance of all the beetles maturing under the bark. The dendrolene 

 did the same where thoroughly applied. The raupenleim has a ten- 

 dency to harden on the surface. This is a good thing where it is in- 

 tended to prevent beetles from issuing from the trees, but a bad thing 

 where it is intended to prevent insects from crawling up the trunk. The 

 dendrolene becomes very soft at high temperatures without running. 

 This prevents insects from crossing it; but where it is applied thin it 

 does not always form a barrier to insects emerging through the bark. 

 Its application is recommended as against the fruit bark-beetle {Scoh/fus 

 rugidosKs), which can not emerge through it when already in the tree, 

 and can not enter the bark ])rotected by a coating. It was also tested 

 against peach borers, and both materials proved ert'ective. 



It was stated by the grower conducting the experiments that the 

 dendrolene killed the borers that were in the tree when it was applied, 

 while the raupenleim did not. This fact nmy have been accidental 

 and is not to be expected under ordinary conditions. The material is 

 recommended for application to fruit trees to prevent attacks of round 



* The entile paper is publislied as Hulletin No. Ill of the Now Jersey AgTii-ultmal 

 College Experiment Station, October, 1895. 



