Leatherjacket pests are not actually insects, but the larval stage of daddy long legs, also known as leatherjacket crane flies. They are around 30mm long, with greyish-brown bodies and no legs, and grow underneath lawns, feeding on grass roots until they pupate and emerge as crane flies between August and October, laying the next generation of leatherjackets. Leatherjackets can cause damage to lawns, small plants in garden borders, and vegetable plots by eating roots. They overwinter in the soil and generally don’t do significant damage until late spring or early summer. Signs of leatherjacket damage include yellowing or browning of grass, thinning of the lawn, and dead patches. Biological control is available for controlling leatherjackets in lawns, flower beds, and vegetable plots, such as pathogenic nematodes that are watered into the turf or soil. The optimal time to treat crane flies/leather jackets is between October 14th and October 31st.