Some of you may be struggling with Leatherjackets at the moment as the UK suffers a crane fly infestation! Leatherjackets are the larvae of crane flies (known as daddy long legs to most of us). They can damage lawns by eating the grass roots are are more prevalent in damp conditions which favour the survival of eggs and larvae. The larvae can cause clusters of yellowing dead grass which when pulled up will reveal the little creatures underneath.
- Leatherjackets have tubular bodies and are up to 30mm long and a greyish brown colour. They have no legs or obvious head
- Lawns develop patches where the grasses turn yellow and often dies. You will find Leatherjackets by lifting the grass and finding them underneath.
- Birds such as crows, starlings and magpies love eating the grubs and will search for leatherjackets in the lawn. Have you noticed an increase in birds around your lawn?
Leatherjackets hatch from eggs laid by crane flies, also known as daddy long legs. Crane flies will lay eggs in most UK lawns and some may never hatch – but if conditions are wet and damp for a considerable amount of time this will cause them to hatch and begin to live under your lawn
Can I Prevent Leatherjackets?
Aerating your lawn regularly will go a long way towards preventing Leatherjackets. They love wet conditions so if you get control of your lawn drainage this will help. There is no chemical pesticide to eradicate leatherjackets at present. Nematodes can be used. Nematodes are microscopic bacterial worms that get rid of leatherjackets by infiltrating their outer casing and subsequently killing them. The correct nematodes are Steinernema feltiae. To be effective, the nematodes require soil that is well drained but moist and with a minimum temperature of 12°C. Nematodes should be applied September to early October.
You can find Nematodes here
Encouraging natural predators like birds and frogs can help keep leatherjackets in check.
You will need to repair the damage caused by the Leatherjackets. You will firstly need to mow your lawn so you can see where the damage is. You will then need to remove the damaged patch of lawn by scraping away the grass; scarifying may help. You can then top soil the area if the patch is not level with the rest of the lawn and sow your new seed. Keep an eye on conditions for seeding.
Update- There has now been full approval for Acelepryn which covers control of chafer grubs and leatherjackets in sports pitches, golf greens, tees and fairways, golf roughs, racecourses and gallops, bowling greens, airfields, and professional application to commercial and residential lawns subject to specific restrictions on the percentage of the area being treated.