112 A MANUAL OF FORESTRY 



in color. They transform into brown chrysalids inside the loosely 

 made shelters. In six to ten days the small brown moth emerges 

 from the chrysalis, dragging the empty case partially out of 

 the larval shelter. The moths are found from the middle of 

 June to the end of July. Shortly after emergence, they deposit 

 their peculiar pale-green scale-like eggs in small oval patches on 

 the undersides of the needles, and they are not conspicuous. 

 The eggs hatch in about a week or ten days, and the young larva; 

 feed for a short time on the terminal shoots of the branches 

 before hibernating. During July when the moths are flying, 

 they occur in enormous numbers about the electric and other 

 lights. . . . They are carried considerable distances by the 

 wind, and this method of dispersal accounts for the rapid spread 

 of the insect." 



Treatment. No practicable method of directly combating the 

 spruce budworm is as yet known. Its greatest damage is done 

 in connection with the spruce bark-destroying beetle. This 

 beetle can be controlled as already described. Where the spruce 

 budworm is found in abundance, especial watch should be kept 

 to see whether the bark-destroying beetle has attacked the 

 weakened trees. 



THE GIPSY MOTH (Porthetria dispar). 



Form of Damage. Since its importation into Massachusetts, 

 the damage done by this insect has been most serious dam- 

 age, by the way, not confined either to forest or fruit trees, for 

 it also attacks other forms of vegetation. The damage done 

 is by defoliation which weakens the tree, and if repeated for 

 two or three successive seasons results in its death. 



The gipsy moth prefers such trees as the oak and maple, but 

 conifers are not immune. 1 It does little damage to the compound 

 leaf species, as the ash, hickory and butternut. Kxperts, there- 

 fore, advise the encouragement in the infected regions, so far as 

 possible, of species with compound leaves. 



Appearance. - The presence of this insert is always apparent 

 in the latter part of the season from the defoliation of the trees, 



1 The red pine is thought to be immune. 



