Leatherjacket Lawn Treatment

Leatherjackets are the larvae of the Daddy Long Legs. The larvae cause damage to lawns by feeding on the roots of grass plants.

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 the roots of the lawn, 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 out 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 grey/brown leathery skin.

Damage to lawns occurs from autumn to spring but is most severe in the spring when the leatherjackets 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.

The time to control the insects is when they are in the larval stage, not flies. They can be controlled by removing by hand or applying a biological nematode, which attacks the larvae, killing them within a few weeks. They are specific to the pest concerned therefore safe for the user, children, pets, wildlife and the environment. The main season for application is late August until the end of October. A spring application can be made in the case of severe infestations if the soil temperature is over 10 degrees Celsius.

How to remove and control leatherjackets in your lawn

To kill the Leatherjackets in your lawn we need to apply a product called Nemasys Leatherjacket Killer. (mixed in a spray with water) It contains microscopic worms called Nematodes. These worms actively prey on Leatherjackets, attacking them through openings in their bodies and infecting them with fatal bacteria.

How to notice if you have leatherjackets in your lawn

Birds pecking at the soil in winter, and at lawns in spring and early summer, are another sign of leatherjackets’ presence. Larger predators may also dig them up from the lawn, causing larger damaged patches requiring repair. You may also notice your lawn discolouring and thinning

Take a look at our pages on Red Thread and Chafer Grubs too.