Io8 FORESTRY IN NEW ENGLAND 



Treatment. — No practicable method of directly combating 

 the spruce budworm is as yet known. Its greatest damage 

 is done in connection with the spruce-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 spruce-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.^ It does Kttle damage to the compound 

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

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

 possible, of species with compound leaves. 



Appearance. — The presence of this insect is always apparent 

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

 but identification is easiest by the discovery of the large egg 

 masses which are oval in shape, about an inch wide and two 

 inches long, of a buff color, and presenting much the appearance 

 of a piece of sponge. These may be found on the bark of trees 

 or under leaves on the ground. The young caterpillar is about 

 one-tenth inch long on emerging from the egg; when full grown it 

 is from two to two and a half inches in length. It has a double 

 row of tubercles down the back, eight blue and twelve red. 

 The pupa is dark brown and from three-fourths to one and a 

 half inches long. The male and the female moth differ widely 

 in appearance. The former is small and of a brown color, with 

 a wing spread of one and a half inches. The female, of a white 



' The red pine is thought to be immune. 



