(may beetle, or June beetle), the common name for two species of beetles of the genus Melolontha, family Scarabaeidae; a plant pest. Its length is 22-29 mm. The body is black; the elytra are reddish brown and covered with white hairs. The larvae of both species of cockchafers are yellowish white (length up to 60 mm) and practically indistinguishable. M. hippocastani is distributed in Europe and Asia; it is found everywhere in the European USSR (except the Far North) and in Siberia as far as Transbaikalia. M. melolontha is found only in Europe; it is in the west and south of the European USSR.
Cockchafers cause considerable damage to young fruit trees, berry bushes, and timber, as well as in truck gardening and field crops. The adult beetles feed on the leaves of trees, predominantly birch, maple, and oak; in years of mass flight they often completely eat off the leaves, causing severe damage to plantings. The flight of the beetles begins in May and in the south, in late April. Ten to 20 days after the beginning of the flight, mating takes place, followed by oviposition. The female deposits at different times a total of 50-70 eggs in the soil and then dies. Cockchafers cause the greatest damage in the larval stage, feeding at first on the roots of herbaceous plants and humus and later on the roots of trees. The development of the larvae in the soil lasts four to five years. Young pines suffer the greatest damage from the larvae of cockchafers. Seedlings and slips damaged by cockchafer larvae quickly die or are retarded in development.
Control measures include the cultivation of forests to ensure growth of healthy and resistant plantings (preparation of the soil with annual or biennial fallowing, proper selection of tree and shrub varieties, and the use of high-quality materials in sowing and transplanting), treatment of plantings with insecticides during the flight of the cockchafers, and application of insecticides to the soil or treatment of the roots with insecticides before transplanting to kill the larvae.
N. N. KHRAMTSOV