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Adult
May / June Beetle



Species: Phyllophaga spp. [Coleoptera: Scarabaeidae]

Distribution:

Over 100 species of Phyllophaga occur in North America.

Hosts:

The adults feed on the foliage of various trees and shrubs. Each species seems to prefer a different set of trees. The larvae are white grubs that can damage turf.

Damage:

The adults emerge from hiding places in the soil or turf at dusk. These adults fly to trees where they mate and feed by making small irregular holes in the leaves. If this feeding occurs when the tree leaves are still expanding the small holes may increase in size and cause the leaves to have a general tattered look. This is most common on oaks and maples.

Description and Life Cycle:

Different May/June beetle species take from one to three years to complete their life cycle. The C-shaped white grubs feed on a variety of roots and organic matter. They occasionally damage turf but are rarely a problem in ornamental beds. The adults range from 1/2- to one-inch in length and they may be light tan to reddish-brown to black in color. Some are covered with fine hair but most are only lightly covered with hairs. They are usually noticed when attracted to lights at night. Generally, mature adults overwinter and these emerge in May and June to mate and feed on plant foliage. By morning, the adults return to the soil to begin laying eggs. Some species apparently feed and lay eggs over several weeks while other species may only feed for a night or two. The eggs take about two weeks to hatch and the small C-shaped white grubs begin feeding on organic matter and plant roots located in the soil. These grubs mature slowly and most species molt into the second instar during the first year. This partially mature larva digs deep into the soil in the fall and winter to escape freezing temperatures. In the next spring and summer, the grubs return to feed and molt one more time. These third instar grubs may mature by August to October and these dig deep into the soil to pupate. Some species feed as grubs for several summers before pupating and a few species complete development in a single season. The adult beetles are formed by late fall but these remain dormant until the next spring.

Control Hints:

May/June beetle adults rarely warrant control and their damage is often undetected until the leaves have finished expanding. This is usually after the adults have finished feeding. Likewise, the grubs rarely reach populations large enough for controls. See Japanese beetle for grub management strategies.