Life history (Apple leaf midge)

Eggs are laid amongst hairs in the youngest tiny leaves in shoot tips, often in large numbers. These hatch in 3-5 days and the larvae feed on the upper epidermis causing the margins to curl and roll round themselves.

Larvae are full-grown in 2-3 weeks and then drop to the ground to pupate in silken cocoons in the soil. Lack of rain may delay the exit of the full-grown larvae from the hardened leaves and hence lengthen the development period. Sometimes, a mass exodus from the leaf rolls by large numbers of larvae occurs when a long period of dry weather is terminated by a thunder storm.

There are typically three generations per year, larvae of the third generation overwintering in cocoons in the soil before pupating in the spring and emerging in late April or May, often during or shortly after bloom.