THE GIPSY MOTH AS A FOREST INSECT. ] 1 



agencies whicli did not exist in America at the time of the eaiiiiT 

 and most alarmiiiij invasions — 



1. The parasites. 



2. The disease. 



3. The character (jf the forests. 



The parasites are promisinjj to become about as eflicient here as 

 in the European forests, and it must not be fortjotten that no more 

 has been chiimed for them tlian that they woukl render the gipsy 

 moth as innocuous here as in its orig^inal habitat. 



The disease, too, is about as edicient here as it is abroad. 



Perhaps it is not too mucli. tlien, to demand that forest conditions 

 in America be ma(h^ to conform a httk^ more nearly to those of the 

 countries m which the gii^sy moth is native, particularly to those of 

 Germany. 



This does not by any means unply the adoption of European forest 

 methods en masse. l)tit rather tliat the forests be given a little better 

 attention and that provision l)e made for the actual or mevitable 

 invasion by the gipsy moth througli the elimination of those trees 

 most likely to be mjured and their replacement by others less sus- 

 ceptil)le and not infrequently more valuable. As a matter of fact 

 this removal and replacement is taking place automatically in tlie 

 territory that has been longest infested, but the natural process is 

 too often accompanied by unnecessary destruction of other trees and 

 unnecessary pecuniary loss. 



RELATIVE SUSCEPTIBILITY OF AMERICAN' FOREST TREES TO GIPSY 



MOTH ATTA( K. 



As has been stated, at the time when the first real invasion by the 

 gipsy moth in the United States was at its height it was believed 

 that scarcely any forest, shade, or fruit tree was resistant to its 

 attack. And, as has been explained, the appearance of disease, fol- 

 lo\\-ing a period of uninterrupted increase of the moth, was accom- 

 panied by a change in this respect. That this change was very 

 largely due to the disease is further indicated by the similarity of 

 the conditions prevaihng in certain Sicilian and Calabrian forests 

 to-day to those prevailing in Medford and Maiden in 1S89. 



The relative susceptibility of certain trees to injury and the relative 

 immunity of others is therefore very largely due to. and dependent 

 upon, the presence of tlisease. But since the disease is ever}"\vhere and 

 bids fair to remain until possibly the gipsy moth is freed of its taint 

 tlirough a long series of generations passed imtler ideally healthy and 

 favorable surroundings, there seems to be no reason why the neces- 

 sary dependence should not be placed in it without fear of serious 

 consequences. 



