Then, these larvae leave the head, drop to the soil surface, and burrow into the soil to form overwintering cocoons. The larvae pass the winter in a resting stage in these cocoons. The following spring, if the soil is moist and warm, the larvae leave the cocoons, move about in the soil, and pupate near the surface. The adult midges emerge from the pupae about 2 weeks later, completing the cycle. There is only one generation per year.
Populations are highest after egg-laying is completed, when the wheat is flowering.
Thus, high populations can occur during years with high spring and summer precipitation and warm temperatures. The duration of egg hatch is affected by temperature, taking as little as 4 day days when warm or as long as 7 days when cool. If the soil is too dry, overwintering larvae may remain in the cocoons to emerge in subsequent years when moisture conditions are more favourable. The larvae may lie dormant for up to 13 years. Larval feeding will cause the kernels to shrivel.