250 



The Spraying of Plants. 



tree and deposits her eggs among the branches. The adult 

 forms of the spring canker-worm rarely appear in the fall, but 

 emerge early in the following year. They closely resemble 

 A . pometaria. 



Treatment. Various measures have been taken to keep these 

 insects in check, the most common being to wrap the trunk of 



FIG. 41. The canker-worm at work ; natural size. 



the tree with some material over which the adult female can- 

 not crawl to lay her eggs. For this purpose tar, or any sticky 

 substance, has been in common use. 1 Cotton has been highly 

 recommended. However, the cheapest and best method to get 



1 Eaupenleim and Dendrolene are two substances recommended by Professor 

 Smith in Bull. Ill, A T . J. Agric. Exp. Sta. 1895, Sept. 



