They remain mostly underground but may feed on the aboveground parts of plants on damp, warm nights. They spend the winter in the soil but do not feed until the weather warms up. Leatherjackets pupate mid- to late spring just below the soil surface. In late summer and fall, adults emerge to start the cycle again.

When should I treat my lawn for Leatherjackets?

The Nematodes (or Steinernema Feltiae) should be watered onto the lawn between August and October when the ground temperature is still warm and moist. This is also the time the adult crane flies lay new eggs which hatch and often start feeding on the lawn before going more dormant over Winter.

What is the life cycle of a leather jacket?

There are a few parts to the leatherjacket's life cycle: emergence of adults from pupae; flight; egg laying; larvae hatch and growth (in four different stages – known as instars); and then larvae pupating (turning into adults). Tipulids spend most of their time as leatherjackets, and hardly any time as adults.