Leather jackets (European crane fly)

Symptoms
Damage to lawns occurs from autumn to spring but is most severe in the spring when the leather jackets are fully grown. Symptoms may appear as yellowing, weak areas of grass where the roots have been damaged. The grass can be easily pulled up with little or no root growth. Damage is usually more severe when the previous autumn has been mild and wet. Secondary damage can also be caused by birds and mammals digging up turf in their search for Leatherjackets.

Spot them
Adult Crane flies hatch from pupae in late July and August and lay their eggs in the ground within 24 hours of hatching. The larvae hatch about 2 weeks later and start to feed on grass roots, which continues through winter and into spring. They stop feeding in May/June when they will pupate in the soil. In general, they stay underground in the day and move up to the turf leaves at night. They are very sensitive to drying and do not survive if they are dried out by the sun. On very cloudy days when the turf is wet you can see the larvae in the turf. They are about 25mm long and have a grey/brown leathery skin.