REPORT OF THE SOCIETY 65 



TWO DESTRUCTIVE SHADE TREE BORERS 



C. B.Hutchings, Entomological Branch, Department of Agriculture 



Ottawa, Ont. 



This paper will deal briefly with two destructive shade tree borers : — 



/. The locust borer, Cyllene robiniaeForst. 



2. The bronze birch borer, Agrilus anxius Gor>\ 



The Locust Borer 



Wherever the handsome black locust tree {Robinia pseudacacia) grows, 

 its worst enemy the locust borer, is also to be found. 



Throughout Ontario and Quebec the locust trees have suffered very 

 serious injury from the ravages of this pest. The attack is decidedly insid- 

 ious and serious damage is often done before the injury is even noticed. 



Life History. The life history of the insect is as follows: the adult is a 

 black velvet beetle, about three-quarters of an inch long, strikingly 

 marked with several yellow bands across the thorax and abdomen. It 

 belongs to the interesting family of Cerambycidae and is, of course, 

 long horned. In August the beetles emerge from the pupal stage and 

 seek the nearest patch of golden rod (Solidago) where they feed freely 

 upon the feathery blooms of this plant during the warmest part of the 

 day. Mating occurs at once and the females, returning to the locust 

 trees, begin energetically to search on the bark surface for crevices in 

 which to deposit their snow-white eggs, their long prehensile ovipositors 

 serving as the chief guide in locating suitable places for oviposition. This 

 activity among the beetles goes on throughout August and the greater 

 part of September. The eggs hatch in eight or ten days and the 

 young iarvae immediately start to bore into the inner soft bark where 

 they construct cells for their winter quarters. In spring the young grubs 

 actively resume their burrowing into the sapwood and heart of the tree, 

 each pursuing a course somewhat at right angles to the entrance tunnel and 

 parallel with the sides of the tree. About July the work is completed. At 

 this time the full grown larva is about an inch long, somewhat cylindrical in 

 shape and of a dull white color. The pupal or transformation stage is now 

 begun and in about four or five weeks the adult beetle eats its way through 

 the frass plug at the outer end of the resting cell and makes its escape to the 

 exterior. 



