PREVENTING THE INJURY 



37 





and their eggs." Similar evidence concerning the value of 

 various other birds as canker-worm destroyers could be readily 

 adduced, did space permit. There is no question that the 

 encouragement of the presence of birds is a quality of mercy 

 that is twice blessed, for it blesseth him that gives and those 

 that receive. 



PREVENTING THE INJURY 



The injuries of the canker-worm may be prevented in two 

 ways : If the trunk of the tree be smeared with some prepa- 

 ration which will prevent the female ^ 

 moths or the worms from ascending 

 it, no injury can result. This de- 

 vice is frequently employed, heavy 

 wrapping paper smeared with print- 

 er's ink or some similar viscid sub- 

 stance being fastened around the 

 trunk of the tree (Fig. 4). There 

 are now upon the market two prep- 

 arations called raupenlelm and den- 

 drolene which are used in place ot 

 printer's ink and serve the purpose 

 very well. They remain sticky for a 

 long time. Various mechanical ap- 

 pliances, in the shape of tin troughs 

 and bands, are also used to accom- 

 plish the same object. 



This banding method is particular- 

 ly serviceable in protecting large elm 

 trees, which are difficult to spray on 

 account of their height. The loose bark should be carefully 

 scraped off the portion of the trunk which is to be covered by 

 the paper, before the latter is put on ; and it is generally worth 

 while to insert a thin layer of cotton wnste, or some similar 

 material, beneath the paper to fill up crevices, and thus prevent 

 any moths or worms from crawling through beneath the paper. 

 Then the dendrolene or raupenleim may be smeared upon the 

 paper to the thickness of about one-fourth of an inch, and left as 

 long as it remains sufficiently sticky to entrap any insect that 



Fig. 4. — Trunk of tree, show- 

 ing paper band. (Original.) 



