Leatherjackets in your lawn? Follow these steps …

By | 10/04/2020
If you have leatherjackets in your lawn it may end up looking like this!
An adult crane fly (Tipulidae)
An Adult Crane Fly (tipula oleracea) sitting on a wall.
Leatherjackets turn into these!

If your lawn has suffered this winter, remember these steps to bring your lawn back for the summer.

Reduce numbers

Reducing the numbers of the grubs in the lawn must be the first step. If you try to repair the lawn with a leatherjacket infestation still in the soil, they will just eat the new grass! You need to make sure the majority have gone (or pupated) before attempting any repairs. This will save you money and time in the long run, and bring you a much better lawn in the end.

But how do you reduce the numbers?

I advise a three-pronged attack to battling these wriggly beasts.

A bucket of leatherjackets grubs
Leatherjacket grubs
  1. Water, cover and collect: Give one area of damaged lawn a good watering. Then place something over that area which completely blocks out the light. Old tiles or patio slabs are good. Thick plastic weighted down also works. Leave it at least overnight and then when you lift it in the morning they should all be sitting on the soil surface. Simply collect them up and feed them to the birds. Doing this regularly will quickly reduce the numbers in the soil.
  2. Garlic Spray: A bitter-tasting spray on the grass will discourage the grubs from eating the grass an they will wriggle away. Hopefully to be caught by birds or swept up off your patio. I have a professional organic garlic spray which I can apply to customers lawns, or you could try to make some yourself by soaking crushed cloves in boiling water overnight.
  3. Nematodes: These are microscopic nematode worms which are parasites to the grubs. When watered into the lawn they are supposed to protect from infection and reduce numbers. However, do not expect miracles from this treatment and the application instructions must be followed to the letter for them to have any chance of working. Don’t rely on nematode control alone, but it is worth trying.
Three Leatherjacket grubs on the surface of a destroyed lawn
Leatherjackets found on the surface of a lawn after covering the area overnight.

Repair the lawn

Repairing the lawn can be done once the numbers of grubs are sufficiently reduced. If they are still in the soil when you try to repair it they may just eat your new grass! I recommend re-seeding rather than turfing the damaged areas. There will be less chance of re-infection with fresh seed. Since there are no pesticide controls available to turf farmers there is a chance your new turf may arrive with chafer grubs or leatherjackets in your lawn from new. That would be a terrible waste of money.

For small areas, follow my picture guide to patch repair.

  1. Loosen and prepare the top layer of soil. Prepare it to a fine tilthe and remove any debris for best chance of success.
  2. Sow new, fresh grass seed. 75 grams per square meter for bare areas.
  3. Rake in and level. This is to get good soil contact with the seed to aid germination.
  4. Water in. This is to start off the seed germination process.
  5. Protect and keep moist. Birds may try to eat the seed and it does not want to be stepped on whilst it is growing. Also remember to keep it moist, especially on hot spring days.

Prevent re-infection

Preventing reinfection is the final step to keeping your lawn looking great for years to come. Leatherjackets are an annual pest. Once they have turned into crane flies and flown there will be no grubs left in the soil. However, how do you prevent them from laying eggs in your soil again? Here are the steps you can take to help your lawn be resistant in future years.

  • Promote deeper roots and healthier grass. Healthier grass is in a much better position to resist being eaten by grubs. A well aerated, healthy lawn is much less likely to suffer damaged and will recover more quickly. Crane Fly’s also seem to prefer grass with high levels of thatch, so scarify, if needed.
  • Increase cutting frequency in late summer. When adults are flying and laying eggs, running a mower over the lawn more frequently will help to disrupt them and suck up any eggs in the soil surface.
  • Autumn nematodes. Applying a preventative nematode treatment in the autumn will help the soil to build up a resistance. However, don’t rely on this alone. An attack can happen to any lawn.
  • Attract birds all year round. Birds are fantastic predators to crane flies and leatherjackets. Encouraging them into your garden all year round and their numbers will reduce. Plant shrubs and plants for them to hide in and bird feeders for winter snacks.
  • Be vigilant all winter. Keeping an eye on your lawn through the dark winter months is important. A professional winter treatment will spot problems before they turn serious. You can then take steps to control their numbers.
Signs that leatherjackets are present.
Signs that leatherjackets are present – Look for eaten grass and holes in the surface.

No more Leatherjackets in your lawn

So, if your lawn has been devastated this winter, don’t despair. Remember R.R.P … Reduce, Repair, Prevent. Follow these steps and you’ll have a great lawn this summer.

For a more detailed look at the crane fly and the leatherjacket larvae, and a look at my complete guide to leatherjackets. This will help you to understand your enemy!

A lovely garden in Exmouth

Further reading on Leatherjackets in your lawn

From The Lawn Man Website Archive:

14 thoughts on “Leatherjackets in your lawn? Follow these steps …

  1. Josie & Rob

    Hello kris
    We have left posts before leather jackets eating our lawn. Our grandson levelled off the remaining clumps of dying roots/grass so now it looks blank soil we still have a huge amount of LJ we water the mud very well and hundred came onto the patio us OAPs were in our shoes doing the Torvil Dean squash and skate on them ( 1.10am) this seems to work well, so this is our nightly routine to try and empty them from the soil so we can re seed, every 100 crushed = 3000 less to lay eggs later. We have bought lots of garlic and boiled and watered this in also with a very course rose thanks for all the tips. Then double doses of the spring and summer Nemetodes. War has been declared!!
    Ps: bought iron sulphate read it makes the lawn roots acidic not sure when to use because of seeding ?
    Regards xx

    1. Kris Lord Post author

      Well done on tackling the bugs.
      I wouldn’t apply Iron to try to acidify the soil. Just get the bugs out and then re-sow the seed as normal.
      Good luck.

  2. Helga Mohr

    My lawn has virtually no grass left after this winter and an infestation of Leather jackets which I was unaware of. There are only a few clumps of wild or weed grass left!!
    Is it better to remove all the earth and replace it before returfing it? It’s only 18 x 18 ft so very small.

  3. Melanie Ide

    I have just applied nematodes on my lawn but it is also full of weeds. How soon can I use Evergreen 4in1 feed and weed? Many thanks

    1. Kris Lord Post author

      Hi Melanie,
      As a professional, I don’t use (or recommend) DiY lawn care products.
      You would be best contacting the manufacturer. There will probably be a customer care line on the packet.

  4. Steve Breading

    Hello Kris
    What concentration do you use when applying the garlic spray? One clove to how much boiling water makes how much lawn treatment for what area? Sorry for the convoluted question but I am intrigued at this idea for a totally natural method of controlling leather jackets.
    Kind regards

    1. Kris Lord Post author

      Hi Steve,
      I use a professional horticultural garlic spray feed so can’t advise on making your own I’m afraid.
      It is worth experimenting with though.

  5. Steve Breading

    Hello Kris
    Would you combine the garlic treatment and the black plastic for better results? Also would Ferrous Sulphate serve as a similar bitter tasting treatment and also be beneficial to the turf? Any others?
    Kind regards

      1. Steve Breading

        Thanks Kris
        Interestingly enough, I found a professional product Rigel-G that contains garlic as one of the ingredients. It is expensive though (about £100 a litre but it covers 1 hectare!). Reading further it says the garlic decomposes into a chemical that is toxic to leather jackets. The primary use for Rigel-G is as a plant conditioner that promotes stronger growth after (typically) an attack by insects. I think I will try the garlic spray first followed in the summer with a good lawn conditioner, then more garlic in autumn. I will keep you posted and thank you for your very helpful hints and tips.

  6. Neil

    Hi Kris, I’ve a terrible leather jacket issue and I’m about to have garden overhaul with new patio and artificial turf. My question is if all leather jackets are not removed before new patio and artificial turf is laid will they just die off underneath ??


    1. Kris Lord Post author

      Insects will not survive underneath artificial grass. Nothing eats plastic grass and nothing can burrow through the hard surface it is laid on.
      It you want to contribute to biodiversity loss, loss of habitat, increase plastic waste in the environment, increase your flood risk and have a horrible plastic garden, by all means, go for artificial grass.


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