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Masked chafers also complete their life cycle in one year and overwinter as grubs below the frost line. Adults and larvae are found in the soil during the day. Eggs hatch in about two weeks and the larvae begin feeding. The females burrow into the soil to lay their eggs (50+). The larvae pupate in late June, with adults emerging in July and August. Unlike the May and June beetles, Asiatic garden beetles complete their life cycle in one year. During the winter of their second year, they pupate and then emerge as adult beetles the following spring to begin the life cycle again. When the soil warms in the spring, the grubs gradually return to the root zone, feeding throughout the growing season. During the winter, the grubs burrow several feet deep in the soil to keep from freezing. Grubs are common in old pastures or where grass is kept short through mowing. They mate and lay their eggs in short grass from May through July. Seedlings that have had root damage in plant beds should not be planted out into the field.Īdult beetles feed on the leaves of hardwood trees, especially oaks. Even after grubs have been controlled, seedlings that have suffered severe root loss from grubs often will not recover and grow properly.

Mortality will occur especially following periods of moisture stress. Young trees will appear stunted with yellow-green color. Small roots will be absent and larger roots are often stripped of their bark. Grubs and other root feeding pests cause poor growth through root loss.

It is not known how much damage they cause to their conifer host however, when numbers exceed one hundred aphids on a single seedling, growth of fine feeder roots appears to be reduced. They appear as large white aphids on the roots. Root aphids feed on conifer roots for part of their lifecycle, then become woolly aphids that feed on ash trees. Adult weevils feed on leaf margins causing a typical crescent-shaped notch.

The adult black vine weevil is also a pest, feeding on more than 100 different kinds of plants with their preferred hosts being rhododendrons, hemlocks and yews. Occasionally they are also pests of seedlings. The black vine weevil grub is similar in appearance to scarab beetle grubs, except they are legless. Size of grubs can vary with species and with age within a species, as all grubs go through several molts before pupating. Grubs have a white C-shaped body with six legs and a yellow to dark brown head. Depending on the species, they can live in the soil for up to three years before maturing into the adult beetle. White grubs such as May and June beetle grubs, Asiatic garden beetle grubs, and masked chafer grubs are the immature stage of scarab beetles. Black vine weevil grub ( Otiorhynchus sulcatus).Asiatic garden beetle grub ( Maldera castanea).May and June beetle grubs ( Phyllophaga anxia, Phyllophaga fusca and Polyphylla comes).There are several species of insects that feed on and affect root growth of Fraser fir Christmas trees either in the field or in seed beds.