Leatherjacket Control

Leatherjackets are the larvae of craneflies (also known as daddy long-legs) and are a common lawn pest. There are more than 350 species of cranefly in the UK, but the ones most likely to be in your garden belong to a group called Tipula, or ‘true craneflies’.

The craneflies lay their eggs just below the surface of the grass. Once they hatch in summer, the grubs will start to feed on the grass roots. However, sometimes these grubs don’t grow large enough to cause significant damage until the following spring. This is when serious issues can begin.

Leatherjacket grubs have grey/black/brown leathery skin which can make them tricky to spot in the soil. They grow to about one inch in length. They do not have legs or a distinctive head.

Identifying Leatherjacket Damage

The first sign of a Leatherjacket problem is likely to be yellowing and weak grass. In extreme cases, you will be able to pull the affected areas of turf up easily as the roots will be completely eaten.

Secondary damage comes in the form of birds and mammals eating the grubs and pecking holes in the turf/ripping it up completely as they do so. If you notice birds pecking at your lawn, this could be a sign of a leatherjacket infestation.

New grass or turf can be particularly susceptible to leather jacket infestations as the adult craneflies show a preference for fresh new grass – especially grass that is in moist and shady parts of the garden.

What is Biological Leatherjacket Control?

Biological controls are non-chemical treatments that rely on the natural enemies of pests. In the case of leatherjacket control, the enemy is the nematode, specifically, the species Steinernema feltiae.

Steinernema feltiae are microscopic worms that actively seek out the leatherjacket grubs, feeding and multiplying inside them, then infecting them with a bacterium. Once infected, the leatherjackets will stop feeding and die. The nematode will then leave the dead leatherjacket and go on to seek out more, repeating the cycle.

Biological leatherjacket control is a highly effective, safe treatment that can be used on turf as well as ornamentals. It is safe for pets and other wildlife and the perfect choice for organic gardeners.

How Many Nematodes Do I Need

We sell biological leatherjacket control in packs that cover the following areas:

• 10m²
• 50m²
• 100m²
• 500m²

There are millions of microscopic nematodes in each pack – carefully worked out to ensure accurate application for each specific area listed. Each application of nematodes will provide at least six weeks control of leatherjackets.

Nematodes are supplied as an easy-to-mix powder which needs to be diluted with water before use. Specific dilution rates are shown in the table below.

How to Apply Biological Leatherjacket Control

Apply to moist compost/soil, when the soil temp is above 12ºC using a watering can or sprayer. 

When to Apply Biological Leatherjacket Control

You can apply nematodes when the soil temperature is above 12°C – typically late summer and autumn, but ideally between September and October. A second treatment may be applied the following spring, from mid-April to mid-May (at double strength).

Nematodes are particularly effective in damp, wet weather. Try and choose a humid or wet day to apply the nematodes. They are UV-sensitive so it is best to avoid applying them on a bright sunny day as they will not survive in these conditions. The best humidity levels are often first thing in the morning or late afternoon

Can I Store Nematodes?

Nematodes are perishable and need to be applied quickly after delivery for best results. They can however be stored in the fridge for up to two days. Please note that delivery can take up to two weeks.