E-75
DEPARTMENT OF ENTOMOLOGY
ornamental insects

JAPANESE BEETLE
David L. Matthew, Jr., C. Richard Edwards, and Timothy J. Gibb, Extension Entomologists

Spot infestations of the Japanese beetle are found throughout Indiana. Most of these occur in or near cities, but a few are found in rural areas. This insect is most damaging to lawns, trees, and flowers; however, corn and soybeans may also be attacked.

DESCRIPTION AND HABITS
The Japanese beetle is about 1/2 inch long, and is metallic green and bronze in color with a row of white spots on each side of its body. Adult beetles are most active in July and August. They can feed upon more than 250 different species of plants, but are especially fond of roses, grapes, smartweed, soybeans, corn silks, flowers of all kinds, and overripe and decaying fruit.
The beetle larvae (grubs) develop in lawns, turf, and cultivated land from eggs laid by the female in midsummer. These larvae, which look like the grubs of ordinary June beetles, feed on the roots of grasses and other plants. They complete their growth the following spring and emerge as beetles in late June or early July.
In areas of heavy infestation, the grubs may seriously damage lawns and cultivated crops by feeding on the root systems, while the adults will attack and injure flowers and foliage.

PROTECTING THE TURF
Control with Insecticides. Any of the materials in Table 1 will protect lawns and turf from Japanese beetle grubs and other soil insects. Select one and apply in the fall or early spring when the ground is not frozen. Dursban and diazinon require annual treatments.
Granules (G) can be applied with a fertilizer spreader or by any means that insures even distribution.
Emulsifiable concentrates (EC, E) must first be diluted in water, then applied as a spray. For small scale spraying, mix the amount shown in the table with 3 gallons
of water, and apply evenly to 1,000 square feet. For large areas of turf, apply with power sprayers or aerial equipment, using the 1 -acre rates in Table 1.
Both spray and granular applications must be watered into the soil for best results.
Control with "Milky Disease" Spore Dust. A specific bacterial spore dust can be used to control grubs in the soil, provided the population level is at least one grub per square foot. The spore dust, sold as Doom and Japidemic, is available in many garden supply stores. It should be applied in the spring or early fall. One treatment is usually sufficient since the bacteria that cause milky disease in the grubs continue to multiply in later generations.

PURDUE UNIVERSITY COOPERATIVE EXTENSION SERVICE • WEST LAFAYETTE, IN 47907