As garden pests go, leatherjackets are one of the most damaging - particularly to UK lawns. If left alone, these pesky little menaces can destroy an entire lawn, so it's important to know exactly what you are dealing with, and how to take back control of your garden.
That's where we can help. In this blog we are going to walk you through how to identify a leather jacket infestation, how to prevent them from entering your garden and then how to get rid of leatherjackets, looking at a few different options including manual and chemical pesticide removal.
What is a leatherjacket?
Leatherjackets are the larval stage (or grubs) of crane flies, which you probably know as daddy long legs. They live just below the lawn surface, only emerging when they become adult crane flies which is usually between August-October. The adult daddy long legs will then lay eggs, and the newly hatched leatherjackets will start the process all over again.
In terms of looks, they are dark (black or brown) in colour, which makes them difficult to see. They are around 2.5 - 4 cm in length, with tough 'leather-like' skin (hence the name). They feed on the roots of lawn grasses, but can also make their way into flower beds.
They are particularly prominent after a wet Autumn as they love damp conditions, and in new build homes as they are attracted to the tender roots of fresh turf.
When do leatherjackets appear?
Leatherjackets are at their most prominent after a wet and mild autumn. Even though leatherjackets hatch in the autumn, you probably won't be aware of them until the spring and early summer - they can start to die off during cold winters, but as the weather gets warm again, they start to reappear. They'll feed on plant roots and seeds, and on humid nights they may come to the surface and feast on plant stems or foliage.
You may notice birds pecking at the soil surface during the winter, which in itself can cause patches in your lawn. They're trying to get at the leatherjackets below the surface.
Signs you have a leatherjacket problem
As they are hard to spot, you may not know that you have a leatherjacket problem until you start to see signs of damage, like bare patches, in your lawn. The first sign is usually that some areas of your lawn are turning a yellowy-brown colour and then start to die.
While birds can be an indicator, there may be many different things they are swooping for, but if you notice a lot of tiny holes where they have inserted their beaks to the ground, that could be another sign. If you get a bout of wet weather in the spring, you may start to see leatherjackets on patios and paths around their garden.
If you suspect that you have a problem with leatherjackets, the best thing to do is dig a few small test holes around the garden - about three inches deep. If you can't see any leatherjackets, check the grass roots to see if it has been interfered with. This should tell you whether you have a problem or not - remember to use a good pair ofgardening gloves.
How to prevent leatherjackets
You can use nematodes to help prevent leatherjackets. This is a form of biological control, and nematodes are microscopic bacterial worms, which can enter leatherjackets and spread disease - eventually killing them.
While this is the most effective form of prevention, nematodes require soil to be moist and warm, so the best time to deploy them is between August and October. Just water them into the lawn, and they can strike just as the new eggs hatch.
One other prevention method is regular mowing - it's not as impactful as the nematodes, but it can help keep them at bay.
How to get rid of leatherjackets in lawns
If you have a major problem with leatherjackets, you may need to call in an expert. A new pesticide product called Acelepyrn has been approved for use in the UK, but it can only be applied by qualified lawn technicians, following an assessment.
For a more natural way of controlling leatherjackets, you may be able to flush out leatherjackets by saturating the soil in your garden with water, and then covering the lawn with a black plastic sheeting. This will bring them all out to the surface by the morning, and you can watch their natural predators, the birds, eat them for breakfast.
Always be on the lookout when you aregardening - by removing any that you can see, you can stop the problem before it starts.
Conclusion
We hope you now have all the tools you need to identify, prevent and eradicate leatherjackets in your garden. The crane fly may look goofy and harmless, but their grubs can damage lawns and other plants if you don't keep watch for them.
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