The Q&A Archives: Japanese beetles

Question: How do I get rid of these stupid things? I have tried everything!

Answer: Adult Japanese beetles are about ? inch in length and coppery-brown in color with metallic green heads. They emerge from the soil and feed from May to August. They lay their eggs in the soil. Grubs hatch from the eggs and feed on grass roots. As the weather cools, the grubs move more deeply into the soil, to overwinter.
Both adult beetles and their larvae (grubs) can seriously damage plants as a result of their feeding. Adult Japanese beetles eat flowers and skeletonize leaves (eat leaf tissue between the veins, resulting in a lacy skeleton remaining). The grubs feed on the roots of plants, especially on the roots of grasses.

Multiple approaches are necessary for controlling Japanese beetles. Adults can be removed by handpicking and destroyed. Japanese beetle traps are available commercially or can be homemade. They may be effective at reducing adult populations.
Keep traps at least 50 feet from the crape myrtle tree or you may create more of a problem by attracting them to the area. Milky spore, Bacillus popilliae, is a disease-causing bacterium that is effective against grubs of Japanese beetles but not the adults. It is commercially available for homeowner use. Carbaryl (Sevin 50WP) or neem oil (Bonide Bon-Neem or Green Light Neem Concentrate) or cyfluthrin (Bayer Advanced Garden Power Force Multi-Insect Killer Concentrate) or permethrin (Spectracide Bug Stop Multi-Purpose Insect Control Concentrate) are labeled for use by homeowners against Japanese beetles on crape myrtle. As with all pesticides, read and follow all label instructions and precautions.

Best wishes with your landscape!

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