Japanese beetle is an insect that injures grasses, trees, crops, and garden plants. The beetle entered the United States about 1916. It probably was accidentally imported in the roots of nursery plants from Japan. It is now found in all states east of the Mississippi River and in the Canadian provinces of Quebec and Ontario.
An adult Japanese beetle measures about 1/2 inch (13 millimeters) long. Its coppery-brown front wings are hard and meet in a line down the center of the back. The rest of the body is metallic-green. Twelve tufts of white hair grow along the back edge of the body.
Adult Japanese beetles live for about two months. The females lay their eggs in the soil in midsummer. The young insects, called grubs, hatch in about two weeks. They have white comma-shaped bodies with brown heads and swollen tails. The grubs burrow into the soil until the following spring. They eat the roots of plants, especially those of grasses. In late May or early June, the grubs enter the pupa (inactive) stage and emerge as adults near the end of June. The adults feed on the leaves, flowers, or fruits of plants.
The United States Department of Agriculture has released several types of parasites that attack Japanese beetle grubs. A bacterial disease, called milky spore, also can be used to kill the grubs. Adult beetles may be killed with insecticides or lured into baited traps.
