Leatherjackets Explained: What to Look For & Preventing Damage

14th Oct 2013

Although 2013 has overall been a much better year compared to last year weather-wise, the difference in conditions can increase the likelihood of certain turf pests.

As you probably already know, Crane flies (or daddy-long-legs to most people), were everywhere in September. They started appearing in July and August indoors and out and by September we see them all the time, including on our lawns.

Anyone who has heard of the words “crane flies” and “turf” used in the same sentence usually knows that the result is Leatherjackets. The crane flies can lay hundreds of eggs in turf, which later hatch after around 2-3 weeks.

The result is the larval stage, called Leatherjackets, which are pests that feed off the grass roots in the turf.

One of the main problems with Leatherjackets is that it can take a while to even notice they are present, at which point quite a lot of damage has already been caused.

When the larvae first hatch, they will tend to feed at a higher level in the turf whilst the weather is still warm. However, as the temperatures start to drop in autumn, they will move down lower, making them harder to identify upon inspection.

Throughout autumn and winter, damage is minimal. However, once temperatures increase again in spring, the larvae move closer to the surface again, making damage far more apparent. The pests will be most active in dry summers meaning that the damage can often be confused with grass lacking in water or being stressed.

The most common and obvious indicator to most people is when birds start pecking away at the lawn to eat the Leatherjackets. The mess left by the birds prompts most people to take a look in the soil, just under the turf level.

How Can I Identify Leatherjackets Before the Damage has Been Done?

Like anything, prevention is always better than cure, so identifying Leatherjackets before next years damage occurs is far better than being hit with the repair costs afterwards.

As explained earlier, identifying that the larvae are present can be quite difficult as damage is minimal at first.

You can test areas of your lawn every so often to try and identify Leatherjackets by using a knife to carefully cut a section of your lawn, so that you can see just under the turf level. Just ensure that the section is cut out very tidily so that it can be put back in place properly afterwards.

Another method is to try and peel back areas of your lawn. If the turf easily rips up like a mat, then you may have Leatherjackets which have already fed on some of the roots.

An old trick which many greenkeepers use is to soak an area and place down a sheet on the area overnight. This makes any Leatherjackets come to the surface of the lawn, making it instantly easier to identify whether they are present or not, and if treatment is required.

If you decide to try this method, just make sure that you put some weight on the sheet to stop it blowing away in the night.

What Can be Done if my lawn appears to be infested with Leatherjackets next year?

Insecticide treatments are required to kill Leatherjackets. Depending on the level of damage, lawn renovation processes may need to be completed afterwards.

All Lawn Master operators are checking customers lawns for the larvae at the moment. If identified, it’s always better to have treatment in say November rather than next year before any real damage is caused.

The pictures below show a lawn infested with Leatherjackets, and the same lawn after treatment and some renovation work.

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Lawn Master This article was written by:

Lawn Master is a national lawncare company in the UK.

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