LEATHERJACKETS (DADDY LONG LEGS)

If your lawn appears patchy and starts to die off in the period December – March, there is a good chance it is infected with Leatherjackets. If this is the case, you need to act straight away as if left untouched, your whole lawn could be eaten away. IDENTIFICATION The symptoms of leatherjackets are :- Grass growth slows and yellow patches appear. Grass is easily pulled up, with little or...

If your lawn appears patchy and starts to die off in the period December – March, there is a good chance it is infected with Leatherjackets. If this is the case, you need to act straight away as if left untouched, your whole lawn could be eaten away.

IDENTIFICATION

The symptoms of leatherjackets are :-

Grass growth slows and yellow patches appear. Grass is easily pulled up, with little or no root growth. Starlings peck at the grass in an attempt to eat the grubs.

To identify the pesky pest, inspect the lawn in areas of discoloration by cutting a 15cm square section of turf on three sides and peeling back the grass and examine the upper 2 inches of root zone for the presence of dark grubs. You can help to see them by shaking or breaking the sample, and by poking tthe soil and roots with a knife. Leatherjackets do not distribute themselves evenly throughout the turf, you should examine a few areas

Leatherjackets are about 2.5cm / 1″ long, greyish black in colour, legless and with no distinct head.

In August many people report clouds of daddy long legs emerging from lawns in early morning and this is a sure sign of leatherjacket infestation. If you have a well drained lawn, chances are they will die off and not affect your grass

LIFE CYCLE

Leatherjackets are the larval stage of the European Marsh Crane Fly, commonly known as Daddy Long Legs. In late summer, adult crane flies emerge from the soil, mate and lay their eggs. The eggs hatch within two weeks. The eggs require moisture and a temperature of at least 14 degrees Celsius before hatching into the larval stage.

Many leatherjackets do not survive the winter especially if exposed to cold, dry conditions. They cause damage to roots, mainly grass, by feeding on them in late Autumn and early Spring when they enter the final larval growth stage. This will continue until early summer when they enter the pupal stage. Adult crane flies then emerge approximately two weeks later.

CONTROL

PHYSICAL

Leatherjackets can be removed manually, using a net, rake or by handpicking. Either crush those collected or place them in soapy water. Good lawn care will also aid in control. This includes frequent mowing and at the correct height (they like to lay their eggs in long or wet grass), addition of fertiliser to help in the recovery of damaged turf. A slow release nitrogen fertiliser is also useful. As damp conditions are necessary for egg and larval development, drainage improvements should be considered, particularly where a clay based topsoil is present.

The removal of wet conditions will reduce optimum conditions for the development of populations of the European Marsh Crane Fly. For established lawns, additional drainage (e.g. forking over or aerating) will lower the numbers of leatherjackets present.

CHEMICAL

If physical control measures are not effective, pesticides or nematodes can be used. Garden centres will be able to give advice on suitable pesticides available to the public.

CONCLUSION

Leatherjackets have ideal conditions to develop when we have a wet and mild autumn and winter. Sites with poor drainage caused by clay topsoils are particularly susceptible. It is a natural occurrence and can often be prevented by good maintenance procedures, and if infestation has already occurred, rectified by following the above advice.