Grape Vine Galls

Asked June 18, 2019, 11:22 AM EDT

Are the Grape vine galls? If so, how does she treat?

Montcalm County Michigan

1 Response

These are grape Tumid galls. Tumid gall maker is a midge, a type of fly. They are also called tomato gall. Usually they are redder. The damage is already done. The window for treatment was probably two week ago. This must be a good year for them as I am getting a lot of calls and samples. Timing pesticide treatment is hard and once the galls form there is no way to kill the larvae. Best treatment is to cut out. There are 2 to 3 generations a year, but later generations only make galls in the leaves. First generation makes the biggest impression.
Tiny holes in the galls indicate that the pest has already emerged. She could spray an insecticide which might reduce next generation which will be on the leaves. They do not attack the fruit. I call it a cosmetic pest. Looks bad but usually does not do a lot of damage