- Leatherjackets mainly attack grass roots. They will also feed on cereal crops and burrow into potato tubers.
- Leatherjackets are the larval stage of crane flies.
- Crane flies, also known as daddy-long-legs, have long thin legs, one pair of wings and a small thin body around 2.5cm long.
- Males and females can be identified by comparing the tip of their abdomens: males - are blunt whilst females - are pointed.
- Adults are commonly seen flying from late August to October.
- Since adults do not feed they cause no plant damage.
- Mating and egg laying takes place within 24 hours of adults emerging.
- Females lay their eggs by 'hopping' on the soil surface. Each time they land they insert their pointed abdomen into the soil and deposit an egg.
- The larvae emerge as small brown grubs. They will begin feeding on root structures of grasses.
- During the day the larvae remain under the soil, but on wet nights may appear above the surface and feed on plant stems.
- Larvae overwinter in the soil until spring, when they begin feeding again.
- There are four stages of larval development.
- When they reach full size larvae they can be up to 4cm in length.
- They pupate in August.
- The pupae have rows of spines along their sides which enable them to move up and down within the soil during wet and dry periods.
- Regular and thorough observation of lawns and plants is essential when wishing to control leatherjackets organically.
- Remove by covering small areas of lawn with black polythene overnight after heavy rain or irrigation. The grubs will come up onto the grass and can be removed in the morning.
- Natural enemies can be released onto the affected plants.
- The parasitic nematode Steinernema feltiae can be watered into the ground around affected areas. These parasites infect the grubs with bacteria to kill them.
- Compacting the soil using a heavy roller will make it harder for the grubs to move through it.
- Regularly check lawns and plants for signs of leatherjacket infestation and deal with them as soon as they appear.
- Encourage insect-eating birds by hanging feeders in the winter months and nest boxes in the spring.