154 



MONTANA EXPERIMENT STATION. 



THE FLATHEADED APPLE-TREE BORER. ~ 



The flatheaded apple-tree borer inhabits Canada and the United 

 States and is a native American insect. It occurs in few places in 

 Montana and in some cases has been very destructive. Young r.rces 

 during the first two years after planting are particularl}^ lialae to 

 attack since the beetle prefers for its host trees those that have been 

 weakened from' some other cause. The hot southwestern sun m the 

 spring of the year often "scalds" the bark on the main stem of young 

 trees. Trees thus affected are attacked and their destruction is com- 

 pleted. 



Various forest and shade trees are attacked as well as apple, pear 

 and peach among fruit trees. 



The female deposits her eggs in cracks and crevices of the bark 

 in the spring and early summer. The larva hatching from the egg 

 bores through the bark and excavates cavities of varying shape and 

 size in the sap wood. Small trees are often girdled. The larva 

 life lasts from one to three years and it is while in the larval burrows 

 that the insect is liable to be distributed on nursery stock. The 

 appearance of the insect, magnified, is shown in the accompanying 

 figure. 



Fig. 3. Flat-headed Apple-tree Borer: a, larva; b, beetle; c, head of male; 

 dk, pupa — twice natural size. (Chittenden, Circular 32, Sec. Series, Div. of 

 Entomology U. S. Dept. of Agr.) 



