I'll suggest that you investigate a product made from kaolin clay called 'Surround'. It's been used for quite some time in orchards, vineyards, and home gardens to protect many kinds of plants from chewing insects. The Rose Chafer is one of the insects mentioned on the label. You can spray the Surround on grapes, but a certain amount of time is required for the clay to wear off. It does wash off, though.

You may want to consider putting the Sevin away. Its use often causes more problems than it solves.

Labeled for organic growers.

Hm, not sure 'Surround' will help much. The grapes have only just started blooming, so wouldn't coating them in clay prevent pollination as well as keeping the pests off?

Chafers are hard to control with sprays, as they bury themselves deep in flowers and sprays won't hit them there, plus they fly in from the neighbor's property. Hand-picking is effective if you have the time. You can bag the grape clusters and spray kaolinite and unbag & hope you can keep them at bay by hand.

Whatever attack you choose, they live part of their life-cycle underground esp. in turfgrass, and you can kill them when underground with several consumer products.

Dan

The clay in Surround disguises the plants the Chafers feed on so thy don't recognize it and then don't feed on them. Used properly the clay is not supposed to inhibit the plants leaves from doing the photosynthesis they need to.

That's right, kimmsr. Most studies even say that the product enhances growth and development. But the rosecrazy a very points about pollination.

You can spray the grape clusters after they have formed, but there's a timing factor regarding flower formation.

I've used 'Surround', by the way, to protect squash and cukes against the dreaded SVB. When whole plants were sprayed, there was considerably less wilt on a hot, hot, sunny day. (Another benefit.)

Dan_Staley,
Please DO tell us what consumer products you know of that will kill them underground. . . . .

This thread is a year old, cheryl. I doubt that Dan will see it.