Answer from NGA
August 5, 2009
|Japanese beetles are a difficult pest to control. Your best bet is a two-prong approach: one to deal with the larvae, one to deal with the adults. Japanese beetle grubs are best controlled by spraying beneficial nematodes on the lawn and garden area. These microscopic worm-like creatures attack only the grubs in the soil and not plants, animals or humans. Spray them in spring when the temperatures are above 55F. For adult beetles, I'd try a new product called whole neem oil. This is different than standard Bioneem in that it is a stronger concentration of this organic spray. Ortho's Rose Defense is another good product for insect control on roses. Good luck with your eradication project!
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