Grape Cane Gallmaker

During pruning, we came upon a problem that we were noticing near the nodes on some of our canes. Leave it to my husband to find the cause of this malady. Our problem is textbook grape cane gall and the causative agent is a tiny snout beetle. We read all about this at grape cane gallmaker, a publication by the New York State Agricultural Experiment Station. There are two different Ampeloglypter species, one which causes grape cane girdling and the other which causes this problem at the nodes. The grape cane gallmaker overwinters in debris on the ground and begins doing it's damage during May and June when the grape vines are about 25 to 50 cm long.
The damage that we were observing was caused by the female hollowing out a small cavity just above a node and placing a single egg into the cavity which she fills with frass. The pupa or larval stage lasts from June to August. If signs of Ampeloglypter damage is seen on a cane, it can be pruned before the adult form emerges.

Not too many of our canes were affected but, now that we know what to look out for, hopefully we can remove affected canes so as to prevent the proliferation of this gallmaker.
Reference:
1. Grape Cane Gallmaker, New York State Agricultural Experiment Station.