Leatherjackets
What are they?
Leatherjackets are the larvae of the Crane fly or 'Daddy Long-Legs'. It's usually in mid to late summer that we see the adult clumsy oversized insects throw themselves about the place only to get caught in your hair or stuck in a curtain.
Leatherjackets (the larvae) look like an oversized grey/cream maggot. They are usually about 2-3cm in length and can be found just beneath the soil, usually when preparing a new bed or digging in compost. You can also find them hiding out in pots but their favourite spot is just beneath a lawn surface. Their most active time of year is right now as they gather up the energy to transform into the adult fly.
The Damage and symptoms.
The Crane Fly larvae are voracious root eaters and the harm they can do to any plant is severe. They are especially harmful to lawns and once they establish themselves can kill off huge patches.
You may notice yellowing and browning patches in an otherwise healthy lawn. This could be damage from animals peeing in that spot in which case it will mostly be burn damage but it could indicate that the roots are being destroyed.
To test the roots of any lawn simply grab a handful of grass and pull gently. It should stay firmly in place whereas if there is substantial root damage it will simply come up sod and all in your hand.
If this does happen the next step is to try and find the culprit. If it is indeed Leatherjackets you will be able to readily spot them just beneath the surface. The same goes for any plant that may look stressed, simply dig gently around the surrounding of its roots and see if you can spot them in the act.
So now you have spotted them, what is the treatment?
If there aren't that many of them, simple home remedies should suffice. They are a favourite food for birds so encouraging more birds to your area will definitely help. You can coax them to the surface of your lawn by waiting for a heavy bout of rain and then covering it with a tarp overnight. When you remove the tarp in the early morning they should have come to the surface and be a breakfast buffet for any passing hungry birds!
For smaller areas such as pot plants and shrubs you can try spritzing the soil with a mixture of garlic and water. It supposedly makes the soil bitter and unpalatable to them and so gets them to move on.
If there is a severe infestation your best bet is to use nematodes. Nemasys is a targeted leatherjacket killer that contains a nematode which introduces fungi and bacteria that will kill them and leave other beneficial insects and animals unharmed. This can be bought in powder form which can be mixed into a knapsack sprayer or added to your watering can. If you have repeated infestations this can be done at the start of every season as a preventative measure.
Happy Leatherjacket hunting!!!
Sophie xx
