Reducing/preventing Japanese beetle damage on organic grapes
How do I reduce/prevent Japanese beetle damage on organic grapes? I've read about spraying a Neem solution on leaves before and during beetle infestation. I've seen mesh rolled up on posts that cover the leaves in beetle season. Other options? Is Neem effective? Readily available at garden/hardware stores? Where would one buy the mesh?
Washtenaw County Michigan
Neem is probably the most effective of the available organically-approved products for adult Japanese beetle control, but it is not highly effective, compared to the synthetic chemistries that are available. It will likely take multiple applications, at as short of intervals as the label allows, to provide some level of protection.
Netting, if a fine enough mesh, would keep the majority of beetles from getting to the vines. However, netting will cause shading, reducing the vine's ability to grow and mature fruit at a very important time of the season. When you see mesh netting on vines, it is usually used only just before harvest, when the birds are starting to become interested in the fruit. I suggest searching for the closest supplier of Neem or netting in the internet, you might be able to locate a nearby dealer or simply order it on line.