Japanese beetles chew holes in leaves, often devouring much of the foliage from roses and other favored plants. When they stop feeding in late summer, the larvae (grubs) become a problem in lawns, where they damage grass by eating roots.
Use row covers to protect plants during the 6 to 8-week period while Japanese beetles are feeding. Plan to hand pick often, by knocking the beetles into a bowl of soapy water. A fungal disease called milky spore can be introduced into lawns, where it infects Japanese beetle larvae.
Japanese beetle populations vary from year to year. Although traps will collect hundreds of beetles, they may attract beetles from far beyond your yard.
Pole beans often are damaged by Japanese beetles, but because the infested leaves are at eye level, the beetles are easier to gather.