Leatherjacket Killer contains the beneficial nematode [ Steinernema carpocapsae ] for the biological control of Leatherjacket larvae in lawns. This is a natural solution for leatherjackets in lawns. Leatherjackets are the larvae of crane flies, otherwise known as Daddy-long-Legs. The majority of the eggs are laid late summer and develop into Leatherjacket larvae in the late summer- early autumn. The larvae feed on grass roots. In high numbers this kills off large areas of grass turning lawns yellow. Secondary damage from animals and birds can be caused as they come and feed on the larvae. This reults in areas of lawn being ripped up. Leatherjacket Killer is easily applied as the nematodes are watered into infested areas between August and October. A spring application can also be made but will need repeating in the late summer Augsut - October. The nematodes in Leatherjacket Killer penetrate and kill the L1 and L2 stages of the Leatherjacket larvae. They are harmless to wildlife, pets and humans.