What are leatherjackets? Identifying and treating lawn damage

What do Leatherjackets look like?

Leatherjackets are grey-brown, legless grubs up to 30mm long with a tough, rubbery skin — which is where the name comes from. They have no visible head, which distinguishes them from chafer grubs, which are creamy-white with legs and a brown head. If you dig into a patch of damaged lawn and find grey-brown, worm-like grubs just below the surface, you're almost certainly looking at leatherjackets.

How do I know if my lawn has Leatherjackets and not another pest?

The key signs of leatherjacket damage are irregular yellow-brown patches appearing from late winter into spring, grass that pulls away from the soil easily with little root resistance, and an increase in birds — particularly crows, starlings, and magpies — probing and pecking at the lawn surface. Birds are often the first visible sign; they're digging for the grubs.

To confirm, cut out a small section of turf in an affected area and check the soil just below the surface. Leatherjackets are grey-brown and legless. If the grubs are creamy-white with legs, those are chafer grubs, which need a different treatment approach.

Why do some years have worse leatherjacket infestations than others?

Leatherjacket populations are heavily influenced by autumn weather. Crane flies lay their eggs in late summer, and those eggs need moist soil to survive — a warm, wet September and October creates ideal hatching conditions and significantly more larvae make it through to winter. Cold, dry autumns tend to result in lower populations. This is why some years see widespread lawn damage across the UK while others pass without issue; it's largely down to what the weather does in the weeks after crane flies emerge.