The Raspberry Cane-borer 243 



THE RASPBERRY CANE-BORER (FIG. 31) 



Oberea bimaculata, Olivier 



The larva of this species is a footless grub, similar to the round- 

 headed apple-tree borer in form, found boring in both blackberry 

 and raspberry canes. It is best known as a raspberry insect, but in 

 Bulletin 23 of the Cornell University Experiment Station, from which 

 the following quotations are taken, an instance is recorded of serious 

 injury to blackberries. In this case the boring larvae were found only 

 in the bearing canes, while in raspberries they attack the young shoots. 



"The mature insect is a long-horned, slender-bodied beetle about 

 half an inch in length. It is of a deep black color, except the segment 

 next the head, the pro thorax, which is yel- 

 low. There are usually two or three black 

 spots on the upper part of this segment, 

 but frequently these are wanting. 



"The eggs are laid in the early summer, 

 usually during the month of June. They 

 were not observed in the blackberry; but 

 when the insect infests raspberries, the 



first indication of the injury noticed is Fi S- 31. Cane-borer. 



,, ... 11- f ^i Oberea bimaculata. 



usually the withering and drooping of the 



ends of the young shoots. If these be examined, there will be found 

 at the base of the wilted portion two rows of punctures encircling the 

 cane about half an inch apart, and between them a small hole in which 

 an egg has been deposited. This double girdling of the cane is done 

 by the beetle with her jaws at the time she lays her egg. It has been 

 suggested that the purpose served by this girdling is the arresting of 

 the circulation of the sap in this part of the cane; and in this way the 

 prevention of the crushing of the tender egg by a vigorous and rapid 

 growth of the tip of the cane." The larvae bore downward in the 

 pith of the cane, probably reaching the root in aTitumn, where they 

 transform and pass the winter. "The burrows are about one-eighth 

 of an inch in diameter; they wind from side to side of the pith, and 

 at frequent intervals penetrate the woody part of the cane. In some 

 of the cases where the woody part of the cane is penetrated, an 

 opening is made through the bark. These openings occur at in- 



