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Home > Bugs > Bugs of Flowers > Japanese Beetle

Japanese Beetle—Popillia japonica

The Japanese beetle is a highly destructive plant pest. Feeding on grass roots, Japanese beetle grubs damage lawns, golf courses, and pastures. Japanese beetle adults attack the foliage, flowers, or fruits of more than 300 different ornamental and agricultural plants.

see also White Grubs

damage to lawn by Japanese beetle grubs grass pulled back to show grubs Japanese beetle larva
Early indications of grub infestation are irregular patches of dry grass, flocking birds, or entire areas of turf being torn up by raccoons, possums and skunks looking for a tasty treat. If grubs have been eating the root system, patches of turf will come up easily from the soil surface, like pulling up a corner of carpeting, and the soil will be full of grubs. The larvae are typical white grubs that are C-shaped when disturbed. First instar larvae are about 1/16 inch long while the mature third instars are about 1¼ inch long.
Japanese beetles on rose Japanese beetles and leaf damage Japanese beetle adult withwinsome fly eggs
Adult Japanese beetles are 7/16-inch long metallic green beetles with copper-brown wing covers. A row of white tufts (spots) of hair project from under the wing covers on each side of the body. Roses are highly susceptible to Japanese beetles. Adults feed on the upper surface of foliage, chewing out tissue between the veins. This gives the leaf a lacelike or skeletonized appearance. Effective biocontrol of Japanese beetles includes winsome fly Istocheta (=Hyperecteina) aldrichi. Adult beetles with eggs on the pronotum, like the one pictured, should not be destroyed.

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[Photos, left to right: M.G. Klein, USDA Agricultural Research Service,; unknown; Jim Baker, North Carolina State University,; Jim Baker, North Carolina State University,; David Cappaert, Michigan State University,; unknown]

It is the policy of the State of Maine to minimize reliance on pesticides. The Maine Department of Agriculture and the Maine IPM Council encourage everyone to practice integrated pest management and to use pesticides only as a last resort. The mention of pesticides in the fact sheets linked to these pages does not imply an endorsement of any product. Be sure that any product used is currently registered and follow all label directions.