The adults are sawflies about the size of a housefly. Two generations hatch each year, causing damage in the spring and again in late summer. Diazinon or malathion will control this insect. Start looking for damage shortly after the leaves have fully expanded. The second generation usually is less severe than the first and does not require treatment.
Further damage occurs as the larvae tunnel through the canes.
This insect also attacks poplar and willow trees, and damage usually is more severe near stands of these trees. The best control is the removal and destruction of infested canes at the first sign of wilting. It is quite active, and runs and flies readily. It sucks plant juices from leaves and young stem growth, causing deformed and brown foliage. Older leaves will be spotted with many tiny light spots.