Answer: Japanese beetles are difficult to control, in part because they fly long distances. You can try to repel them using a spray containing neem, or you can handpick them (they are sluggish early and late in the day), or you can spray with carbaryl(the active ingredient in Sevin) but this is a contact insecticide with no residual action. You can also use beneficial nematodes or milky spore disease to kill them at the grub stage although this must be done over a wide area to be effective. Be sure to read and carefully follow all of the label directions on any product you use. The traps are not recommended because they seem to attract more than they catch. Most gardeners find they have to tolerate a certain amount of damage, and some years are more severe than others.
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