Yes, I know people (mostly exhibitors) who use it. They create little bonnets for the blooms. You'll probably want to cover the blooms when they are about half open. JBs will get to them at about this point. Actually, they'll get to them even in bud, but you can try.

I'm talking about roses. You don't say what you want to cover...

Thanks for the reply. I actually was going to apply it to my blackberries. The japanese beattles decimate the crop. Last year I got zero berries. They destroyed them. So I was wanting to go into this year with a real plan. I was looking on gardeners supply. They have some row cover thats 80 percent transparent. I could rap the bushes with these and at least save most of the crop. I would think anyways.

Floating Row Covers have been used by many people as pest control devices over the years, as well as season extenders. You just need to be sure there are no entry points for the insects to enter. In addition to keeping potential pests off the plants the FRCs will also prevent the pollintators from reaching them.

Row covers will be problematic on crops with thorns, although the holes created by wind will allow less leaf area open to the sky than no row cover at all.

Dan

I agree with Kimmsr about the pollination issue, no pollination, no fruit.

A wild guess, how about milky spore in the ground to keep the beetles in check thereby mitigating their impact?

The size of the Blackberry bushes could be a problem and hassle with trying to cover them with FRCs. You will have to make sure there is no entry sites for the JBs to get in. If there is a way in insects will find it.

How about hand picking the beetles? That's what we do.