Leatherjackets

Leatherjackets are the larval stage of the crane fly or daddy-long-legs.

Leatherjacket larvae are about 2.5cm (1" long), greyish black in colour, legless and with no distinct head.

In summer leatherjackets pupate. In August they start to lay eggs re-infesting lawns. Within two weeks eggs hatch. The young start to feed, continuing throughout winter, ready to gorge on grass roots in spring. Grass growth slows and yellow patches appear. Grass is easily pulled up, with little or no root growth.

In August gardeners may see clouds of daddy-long-legs emerging from lawns in the early morning and this, as well as the listed damage, are sure signs of leatherjacket infestation.

Starlings peck at the grass in an attempt to eat the grubs.

Wildlife, such as foxes and badgers, can also create a lot of damage as they dig up your lawn in search of grubs for food.

There is no chemical control for leatherjackets.

Leatherjacket Killer

Apply when the young leatherjackets are active in the soil, this is typically late August through to the end of October.

When you start to see the adult daddy-long-legs in your garden (towards the end of August) you will know that in a few days they will be laying eggs. These will hatch quickly, therefore, aim to apply about a week to two weeks after you see the adults.

Apply to moist lawns when the soil temperature is above 12ºC (54ºF) and water them in well. The nematode needs to be washed well in so that they reach the roots where the leatherjackets will be. Make sure the lawn does not dry out after applying nematodes.

Immediately after applying the nematodes, water the grass well so the nematodes are washed into the soil to reach the roots where the leatherjackets will be. Make sure the lawn does not dry out after applying nematodes. Keep the lawn well watered for at least two weeks.

The nematodes (Steinernema feltiae), seek out the leatherjackets and attack the pest by entering natural body openings. Once inside, they release bacteria that stops the pest from feeding, quickly killing the pest. They do not stop there. The nematodes reproduce inside the dead pest and release a new generation of hungry infective nematodes, which disperse and search for further prey.

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