University of Vermont Extension
Department of Plant and Soil Science

Asiatic Garden Beetle                       EL 247

by G.R. Nielsen, Former Extension Entomologist, Plant and Soil Science Department

A native of Japan and China, where it is not an important pest, the Asiatic garden beetle* (AGB) has been known
from New Jersey and New York since the 1920s. In Vermont, the AGB is commonly seen in the lower Connecticut
River Valley but is occasionally seen, usually at lights at night, throughout Vermont.

Life History/Description: The Asiatic garden beetle has four life stages: egg, larva, pupa, and adult. Its life history is
similar to the Japanese beetle, EL 37, and the rose chafer, EL 39. There is one generation per year. The eggs are laid
in the soil in clusters of up to 20, held together by a gelatinous material. The larva, or grub, is a typical C-shaped
scarab grub. There are three instars. The larva is white with a brown head capsule and six legs. The larva has a
V-shaped anal opening and there is a single transverse row of curved spines on the underside of the last segment. The
May beetle white grubs have a Y-shaped anal opening and two longitudinal rows of spines (see EL 200, "Grub Rastral
Patterns"). Mature grubs are about 3/4 inch long. The larva pupates in an earthen cell. The pupa differs in having a pair
of pointed processes at the corners of the tip of the abdomen. The adult is a small chestnut-brown, velvety, sometimes
almost iridescent, scarab beetle. The wing covers (elytra) do not entirely cover the abdomen.

The larvae pupate in late June, with adults flying in July and August. The adults are highly attracted to light and may be
very numerous at windows, doors, or wherever there is a bright light. The females burrow into the soil to lay their eggs
(50+). Eggs hatch in about 2 weeks and the larvae begin feeding.

Damage: The AGB attacks over 100 plants, feeding on both foliage and blossoms. In Vermont, it is never as
destructive as its Asian relative, the Japanese beetle. Further south it has been extremely destructive, completely
destroying both foliage and flowers.

The larvae are seldom uniformly distributed over any large area. They show a preference for grasslands, but may be
found in flower and vegetable gardens. Moist, loamy to sandy loam soils are preferred. The larvae apparently feed
scattered at different depths and do not as severely prune the roots off close to the surface as Japanese beetles do.
The larvae feed upon the roots of practically all plants. Larval populations of up to 100 per square foot have been
recorded under favorite hosts, such as orange hawkweed (Hieracium).

Hosts: Many fruit, vegetable, perennial and annual flowering plants, trees and shrubs as well as weeds and grasses.

Control: In lawns and other turf areas, the AGB may be controlled as with other white grubs.

Contact your local lawn and garden dealer or your local Extension office for current chemical recommendations.

*Asiatic Garden Beetle, Autoserica castanea (Arrow)

Before using any pesticide, read the label and follow all precautions!

Edited in January 1997, based on material developed in 1989.

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