Raspberry Cane Borer
The raspberry cane borers, Oberea bimaculata (Olivier), are slender beetles, about 1/2 inch long, with antennae about as long as the body. The beetles are black except for a section behind the head that is bright orange with two or three black spots. The beetles appear in raspberry plantings in June, and the females deposit their eggs singly in the pith of the tender new growth, about 6 inches below the tip of the cane. The beetle makes two characteristic rows of punctures that encircle the cane about 3/4 to 1 inch apart; between these, but nearer the lower row, an egg is inserted. The girdling of the cane causes the tip to wilt. When the eggs hatch, the larvae tunnel toward the base of the cane. By one account (MacNab and Tetrault), the larvae reach the base of the cane by fall. By another account (Mills and Dewey) the larvae spend the first winter within an inch or two of the row of punctures and then complete their journey to the base of the cane the next growing season. In any case, the cane is weakened and usually is killed before the fruit matures.
Remove wilted tips several inches below punctures by midsummer. Remove and destroy older canes whenever they are observed. Destroy any nearby wild brambles.