Hello,

That looks like an Asiatic Garden Beetle, Maladera castanea (Coleoptera: Scarabaeidae). The Asiatic garden beetle is a recent arrival to Michigan.

The following was modified from a University of Vermont web page at http://pss.uvm.edu/ppp/pubs/el247.htm. It was written 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. 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.

The following was modified from the University of New Hampshire article found at https://extension.unh.edu/resources/files/Resource000542_Rep564.pdf

Control: Prevention and non-chemical control AGB are night feeders who hide in the soil around plants during the day. Gardeners who notice damage to vegetable, fruit or ornamental foliage, particularly around the leaf margins, without seeing the destructive pest itself can monitor for presence of AGB by visiting the garden at night and shining a bright light down onto the soil. Adult beetles will be attracted by the light.

Spun-bonded fabric row covers may protect herb and vegetable planting beds against the predations of adult AGB,unless larvae have overwintered in weedy garden soil. Prevent overwintering by cleaning up the fall garden, tilling under or composting all weeds and plant debris.

Chemical control: Cyfluthrin (Bayer Advanced Vegetable and Gardern Spray), bifenthrin (Ortho Bug-B-Gone) will provide excellent adult beetle control. Other products that will provide some control are carbaryl (Sevin), malathion, rotenone or pyrethrins will help control adult AGB feeding on plant foliage, but during seasons when beetle populations are abundant even several applications may not result in total control.

Merit (imidacloprid), applied in early spring in areas infested with AGB the previous summer, will control larvae. Apply any pesticide according to label directions.

For injury to corn by the grubs see https://www.pioneer.com/home/site/us/agronomy/crop-management/corn-insect-disease/asiatic-garden-beetle/

Be sure to read and follow all instructions and safety precautions found on the label before using any pesticide.

Best regards,

Howard

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