Leatherjackets are about 1″ long, greyish black in colour, legless and with no distinct head. In August many people report clouds of daddy long legs emerging from lawns in early morning and this is a sure sign of leatherjacket infestation.
If your lawn appears patchy and starts to die off in between December – March, there is a good chance it is infected with Leatherjackets. If this is the case, you need to act straight away as if left untouched, your whole lawn could be eaten away.
Leatherjackets are the larval stage of the European Marsh Crane Fly, commonly known as Daddy Long Legs. In late summer, adult crane flies emerge from the soil, mate and lay their eggs. The eggs hatch within two weeks. The eggs require moisture and a temperature of at least 14 degrees Celsius before hatching into the larval stage. Many leatherjackets do not survive the winter especially if exposed to cold, dry conditions. They cause damage to roots, mainly grass, by feeding on them in late Autumn and early Spring when they enter the final larval growth stage. This will continue until early summer when they enter the pupal stage. Adult crane flies then emerge approximately two weeks later.
They have stopped damaging lawns now and will be in their final larval growth stage before they enter the pupal stage and emerge as Crane flies, or Daddy Long Legs, two weeks later. These pesky things will mate and lay their eggs in the soil and start to feed on roots of grass in the Autumn.
If your lawn is free draining, there is much less likelihood of them surviving, as they love wet and damp conditions.
The best ways to control leatherjackets is Chemically using Nematodes, which can be bought easily off the internet. You can also remove them manually, using a net, rake or by handpicking. We suggest you either crush those collected of place then in soapy water.
The removal of wet conditions and keeping your lawn in good condition by frequent mowing and aerating using a garden fork should also help as a preventative measure in reducing the numbers of leatherjackets present.