164 THE GYPSY MOTH. 



in spraying with contact insecticides. A tree in Swamp- 

 scott, the trunk of which was covered with caterpillars, 

 was sprayed, killing nearly all at one spraying. Excellent 

 results were obtained wherever the liquid was carefully 

 mixed and applied. It is poor economy, however, to use 

 contact insecticides except where the larva3 are very numer- 

 ous, for elsewhere they may be more rapidly and cheaply 

 killed by hand, either by burlapping the trees or by other 

 methods. 



While the use of soap powders upon the gypsy moth has 

 some advantages, it is not to be recommended except in the 

 most extreme cases and with the exercise of great care and 

 judgment. 



Measures for Destroying all Forms of the Moth. 

 The methods thus far described have each been intended 

 for the destruction of a particular form of the moth. The 

 methods hereinafter described are intended to facilitate or 

 secure the destruction of all forms of the moth, and have 

 been used with a view to preventing the creature's spread 

 and securing its extermination. It has sometimes become 

 necessary to destroy all vegetation in an infested spot in 

 order to prevent the moth's rapid spread and wide dissemina- 

 tion. For this purpose fire and the axe have been resorted to. 



Cutting and Burning. 

 As an exterminative method for use in wooded tracts, the 

 felling of trees and their destruction, together with that of 

 all other vegetation, by means of fire has no equal in point 

 of expedition and economy. This can only be done advan- 

 tageously, however, on lands where the timber is of little 

 value, as the damage caused and expense incurred by treating 

 valuable woodland in this way would be great. This method 

 is expedient only where a badly infested spot is found in 

 woods not otherwise infested and where by vigorous and 

 immediate exterminative methods the pest may be stamped 

 out. When a colony of this kind is discovered, the trees may 

 be felled to best advantage in the fall or early winter. At the 

 same time the undergrowth can be cut close to the ground and 

 burned together with the tree-brush, or it may be left to dry 



