Japanese beetle in raspberry bushes
I had an infestation of Japanese beetles in my raspberry bushes. They didn't kill the plants, but definitely stressed them. I understand that to get rid of the beetles I would need to spray the plants with pesticide. This would render my raspberries inedible for the season, or perhaps longer. Are there any other solutions? Would it be best to dig up the raspberries and start again in a new location? I really hate to do this, as the bushes have been very good producers, except for this past year. Thank you.
Denver County Colorado trees and shrubs
If you don't want to use chemicals, hand-picking is the best option. Depending on the size of your patch, could you exclude the beetles from your plants with a shade cloth barrier erected prior to mid-June when the beetles start flying?
Here's some advice from the Minnesota Extension about Japanese Beetles and raspberries:
'[F]or fruit growers, Japanese beetles are best controlled as adults. Physical removal is a viable option for small raspberry patches. Remove the beetles by hand and put them in soapy water. Hand picking is most effective as the beetles first arrive, before they release their aggregation pheromones to attract others. The best time to handpick beetles is in the evening and early morning, when they are less active. Don't use Japanese beetle traps. Research has shown that traps attract more Japanese beetles than they catch, and will typically cause more damage to plants in a garden.
Insecticides can help manage adults. Neem extracts like Azadractin have been shown to provide short term protection, especially if only small to moderate numbers of Japanese beetles are present. There are several contact, residual insecticides including permethrin, bifenthrin, malathion or carbaryl. When using insecticides, always read and follow the label. Be sure the specific product you intend to use is labeled for raspberries.'