Latin name: Melolontha / Melolontha hippocastani
Russian name: Western May bug / Eastern May bug
Type of pest: Multi-pest, fruit and crop protection pest.
Row: Coleoptera – Coleoptera
Damage to forest and fruit crops.
Beetles 21 – 31 mm long, body elongated-oval, black or black-brown; elytra oval, with five narrow ribs; the front back is brown. Egg size 1.5 – 2 mm, spherical, white. Larva – up to 60 mm. Pupa with two processes on the apex of the abdomen.
Overwintering larvae and beetles in the soil. The beetle years begin in the last decade of April and lasts more than a month. The beginning of summer coincides with the beginning of the blooming of leaves on the trees. The mass exit of beetles is observed at a soil temperature of 9-14 ° C at a depth of 10 cm. They fly at dusk and at night, less often during the day. They damage the buds, leaves of trees and bushes. In some years, with low relative humidity during the summer, beetles feed on the ovaries of fruit crops – apple trees, plums, apricots. After mating, the females burrow into the soil to a depth of 10-15 cm and lay 20-30 eggs each. Fertility – 60 – 70 eggs.
After the last event, egg-laying bugs die without leaving the soil. After 25-30 days, larvae are born, which by the autumn feed on small roots and humus. In the spring-summer period, horizontal and vertical movements are carried out, concentrating in soil layers with a moisture content of 6 – 7% and a temperature of 17 – 20 ° C. In September, the larvae go 1 m deeper into the soil. This is due to the low cold resistance of the larvae. Their death begins at a temperature of -0.7 … -1 ° C. The development of larvae lasts 4 years. After each wintering, the larvae rise to the upper horizons of the soil, pass into the next century and continue feeding. After the third wintering in June – July, they molt once and burrow into an earthen cradle to a depth of 20–50 cm. The pupa develops for 30–40 days. The newly formed beetles remain in the earthen cradle until spring.
Four-year generation. In the far south, it could be for three years. Older larvae cause significant damage to the roots of trees and other crops. Seedlings and seedlings in nurseries and young plantings are especially severely affected by the damage.
The number of beetles sharply decreases in cold and low snowy winters due to the freezing of larvae. In wet years, the larvae die from a number of diseases (smallpox – Entomoxvirus melolonthae, dropsy – Morator lamelicorniarum, microsporidiosis – Nosema melolonthae, affecting the fatty body, green muscardine – Metarrhizium anisopliae, milk disease – Bacillus fibrogenesis, etc.).
Beetles are destroyed by a cuckoo, a goat’s duck, a rodent, a hoopoe, a rook, a jackdaw, a jay, a kestrel, a young mare, a magpie, a starling, a golden oriole, a rogue, bats, and other moles, badgers, and hedgehogs. Protective measures. Attracting insectivorous birds to forest stands. The laying of nurseries no closer than 200 – 300 m from the stands is the place where beetles are concentrated. In nurseries with a population of more than 5 larvae per 1 m2 – The introduction of granulated insecticides into the soil. Loosening of soil in nurseries at the beginning of a massive summer of beetles. In the summer years, the destruction of beetles on fodder plants by treatment with insecticides. On young landings – shaking beetles on bedding in the morning, followed by their destruction.