Wednesday, June 24, 2009

Japanese Beetles Bring Appetites to Southwest Missouri

The Japanese beetle (Popillia japonica) is about 1/2 inch long with a shiny metallic-green body and bronze-colored outer wings. The beetle has a row of five lateral tufts on each side and one each on the last segment of the abdomen. Photos by Lee Jenkins, MU Extension.

By David Burton
University Extension

Adult Japanese Beetles are on the move in southwest Missouri and they have brought an appetite with them according to Patrick Byers, horticulture specialist, University of Missouri Extension.

These insects can quickly defoliate over 300 different types of ornamental landscape plants by eating the tissue between the veins of leaves and flowers, a type of feeding called skeletonizing.

Trees and shrubs most attractive to adults include: Japanese and Norway maple, birch and pin oak, sycamore, plums, elm and cherry trees, rose, willows, lindens and Virginia creeper. The grubs will also feed on a wide variety of plant roots of ornamentals and turfgrasses.

"Roses, crepe myrtle, grapes and the Japanese maple seem to be this beetle’s favorite food. The main concern in our area is adult beetle damage to broad-leaved plants," said Byers.

Adult Japanese Beetles are a brilliant, metallic green color, generally oval, 3/8 inch long and one-quarter of an inch wide. The wing covers are copper-brown and the abdomen has a row of five tufts of white hairs on each side. These white tufts are essential to the insect identity.

According to Byers, there are four main control strategies available to the homeowner.

Hand picking. “When the first adults arrive on a property, you can pick off these scouts (which attract more pests) and destroy them by dropping them into soapy water,” said Byers.

Use traps. “Traps are effective only when landscapes are isolated from other Japanese beetle breeding areas or when everyone in the neighborhood uses traps. Otherwise, traps attract more beetles into the area than would normally be present,” said Byers.

Insecticide Spraying. “Adults can be controlled by spraying plants. Orthene, Sevin and Malathion, are a few products for control of the adult beetle. During heavy adult activity periods, sprays may be needed every five to 10 days for effective control,” said Byers.

Plant Non-Attractive Plants to the Japanese Beetle. “Another approach to preventing Japanese beetle damage is plant selection. Mississippi State University Extension Service has a publication guide for selecting landscape and garden plants based on susceptibility to adult Japanese beetles. Get this publication online at or contact the Greene County University of Missouri Extension Center at (417) 862-9284.

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