Cane maggot

Young raspberry and blackberry cane tips suddenly wilt and discolor with purple streaking where the maggot girdles the stem just below the terminal bud; look for a tiny hole about 1mm in diameter near the tip. In Western Washington caneberry patches, this pest emerges in late April, with wilting becoming obvious in May. The larva tunnels downward inside the cane before dropping to pupate.

Prune off infested canes several inches below wilted areas and dispose in sealed containers. Remove nearby wild blackberries to reduce pests. Keep caneberries vigorous with consistent irrigation. Parasitoid wasps provide excellent natural control when broad-spectrum pesticides are avoided.