Leatherjacket Lawn Pests – The Complete Guide

By | 15/03/2019
Lots of leatherjacket grubs
Updated: June 2020

Download my leatherjacket fact sheet

This is a summary PDF of this blog post in an easy to see, printable format.


What are leatherjackets?

Two leatherjacket grubs
Two leatherjacket grubs

A leatherjacket is the common name for the larval stage of an insect called a crane fly. They are in the Tipulidae family of insects. In the UK, two species of this family are pests to lawns. These are tipula oleracea and tipula paludosa. Oleracea is the much more common species.

The adult form of these insects are commonly known as daddy-long-legs. These are the large, clumsy insects which fly around our gardens in late summer and early autumn. They are often seen bumbling along the ground, getting trapped in windows and flying into our faces when we least expect it!

An adult crane fly (Tipulidae)
An adult crane fly (tipula oleracea) sitting on a ledge.

The leatherjacket life cycle

The adults are active in late summer into autumn. After they mate, the females lay their eggs on scrub grassland and on lawns. These eggs hatch into grubs two or three weeks later, depending on conditions. These grubs (the leatherjackets) move through the soil and feast on roots of plants found around them. They reduce their activity and dig deeper into the lawn in the winter due to the cold, but start up again in the spring. They need to eat more as the grow larger. Affected plants die suddenly. Lawns can be devastated.

The four life stages of the lawn leatherjacket and crane fly
Crane Fly (leatherjacket) life cycle stages

In late spring the grubs pupate, forming a protective layer around themselves. Inside this pupae the insects transform over several weeks into the adult crane fly.

Leatherjacket pupae
This is the hard-cased form which the leatherjacket grub takes on once it is ready to change into a crane fly.

They then emerge when they are ready. Unfortunately for them, their adult lives are very short. Their only aim is to find a mate and lay eggs for the next generation. They don’t even have any mouths to eat food! As soon as their energy has been expended, they die, leaving the next generation as eggs in your lawn.

Leatherjacket and crane fly life cycle diagram
The life cycle of a crane fly, from leatherjacket grub to adult.

How can you spot leatherjacket grubs in your lawn?

Finding out if you have a leatherjacket infection in your lawn is quite simple. You only need a small pocket knife and good knees. Firstly, have a general look at the lawn and see if you see any patches of obviously dead or dying grass which seem rather out of place or randomly distributed. Down on the ground, have a closer look at these areas. First thing to do is to grab a handful of grass and try to pull it up. Healthy grass will not budge, being held in place by the roots. Grass subjected to a heavy grub attack will come away easily, almost like a carpet. This is because the roots holding it to the ground have gone.

Leatherjacket damage on grass
Leatherjacket damage on a lawn.
Leatherjackets surface feeding evidence
Evidence of leatherjackets in a lawn. The RED arrow is a hole which the grub made to come to the surface. The BLUE arrows near the hole show grass plants eaten by the grub.

Next, dig into the lawn and have a look to try to identify a grub. This is important as you need to confirm the pest you are trying to deal with. In a UK lawn you are only likely to encounter leatherjackets, chafer grubs, cutworms or wireworms. Wireworms are thin and orange. Cutworms are quite large, ‘C’-shaped blue-grey caterpillar type grubs. Chafer grubs are white, usually curled up in a ‘C’ shape with a black head. Leatherjackets are darker coloured, straight and can be between 0.5cm to over 2cm long.

Leatherjacket grub close up
A close up photo of a Leatherjacket grub.
A selection of wriggling leatherjacket grubs dug from a lawn in Exeter

What damage can leatherjackets do to your lawn?

In large numbers, leatherjackets can be a very destructive lawn pest. They can destroy a lawn completely. Such a severe attack is unusual, but even lighter damage can dramatically affect the look of your lawn which may require expensive repairs. The best way to deal with any possible infection is to make sure that it doesn’t get out of hand. Just one or two leatherjackets in a lawn will barely be noticed. When the they appear in large numbers you should be concerned. Measures to keep population numbers down should be taken as soon as they are detected in a lawn.

Leatherjacket lawn damage
A lawn in Exeter destroyed by leatherjackets over winter.

A mild, damp winter will bring leatherjackets closer to the surface and they will be able to keep feeding. As a result, damage to lawns in spring is always a lot worse after a mild winter. If your soil does not freeze in winter, be on the lookout for grub damage in the spring.

Further problems can arise from large animals taking an interest in the grubs. They offer a tasty meal, especially during the lean winter months. If a large population of grubs are found by a badger, fox or even birds, the subsequent damage to a lawn can be devastating! A lawn can be ploughed up overnight and will need to be repaired.

Lawn damage cause by an animal finding leatherjackets
Lawn damage cause by an animal finding leatherjackets.

How can you control leatherjackets?

There are no chemical treatments or pesticides available to control leatherjackets!

Environmental legislation withdrew all professional and home use insecticides in 2015.

The only way to control a leatherjacket infection in 2020 is to try to control populations using non-chemical methods. Here are a couple of different approaches you can try. Like most garden pests, the best results come from using several methods rather than just relying on one.

Method 1 – Prevent the eggs being laid in the soil.

In late summer, you may notice the adult crane flies flying around your garden. This is when the next generation of leatherjackets are being produced. The adults do not live for very long and their only task is to mate and lay eggs. Preventing these eggs from getting into your soil will drastically reduce the chances of a leatherjacket attack the following winter. Once you see the adults, increase your mowing frequency and collect all the grass clippings. Even if the grass it doesn’t need mowing! This will remove a lot of the crane fly eggs from the surface of the soil before they germinate.

Method 2 – Black plastic sheeting.

You may be able to encourage the grubs to the surface of the lawn using black plastic sheets, tarpaulin or thick bin-bags.

First, you thoroughly wet an infected area of the lawn with a hose or watering can. This helps the grubs move through the soil. Then lay a thick plastic sheeting (not ground cover or anything which lets light through) over the lawn overnight or for a couple of days. Secure it with some stones or pegs. Then, remove it in the early morning and the grubs should be on the surface of the lawn. You can then either mow them up or leave them as a nutritious breakfast for the local bird population. Move the sheets to another affected area of lawn. This is an easy method for homeowners to keep the leatherjacket population down without professional help.

Method 3 – Nematode biological control.

A nematode worm
A nematode worm

This modern, natural treatment utilises a parasitic nematode worm called steinernema feltiae for the control of leatherjackets. After correct application to the soil, these microscopic worms find a leatherjacket grub as a host and infect them with a specific species of bacteria. This multiplies and kills the grub. Nematodes have to be applied under very specific conditions. They must be refrigerated upon delivery and then applied when the soil is warm and moist. Watering in the treatment is also very important as the nematodes must come into direct contact with the insect grub. These restrictions on the treatment mean that I am unable to offer it as a professional treatment, but it is available to homeowners online. Just google Leatherjacket nematodes for more information.

Method 4 – Garlic Spray (experimental control).

Farmers in Scotland are trailing garlic sprays as a treatment to keep leatherjacket numbers down. This has so far looked encouraging, especially for an autumn treatment. I will be starting a trial of this myself for lawns in 2019.

Update April 2020: Partial success with garlic

The garlic spray method does seem to have a good effect at encouraging the grubs to leave the lawn. However, if there is a huge population or the grubs have nowhere to go, this method may only move them around!

Getting them out of the lawn and a target for birds and other predators is a good thing though. I have added this to my treatment recommendations.

Method 5 – Encourage insect-eating birds.

Birds are natural predators of crane flys and relish the high populations of these insects in late summer. Encouraging birds into your garden with a variety of plants, water and bird feeders will build an army of predators which will keep a lookout for crane flys. They will despatch them before they even get a chance to lay their eggs in your lawn.

A Great Tit
A Great Tit © Francis C. Franklin / CC BY-SA 3.0

Method 6 – Dig them out!

For small areas it is quite possible to manually dig out the grubs. Using a knife or thin trowel cut into the soil in the affected area and look through the soil for the grubs. Pick them out and put them on the bird table. A few sessions of grub hunting should help minimise further damage and the lawn can be repaired with some seed.

Method 7 – Encourage strong grass roots.

If your lawn has not yet been attacked then you can minimise damage to grass by keeping it as healthy as possible. Grass with a shallow, weak root system will struggle with an insect attack. Deep roots from a strong, seeded lawn will be better equipped to cope and re-grow lost root mass. Aerate your lawn regularly and keep to a quality feeding programme to keep the lawn as healthy as possible throughout the year.

Method 8 – Beer spray (experimental control).

Update April 2020: I did not have any success with using beer to control leatherjackets. It seems it is best to just drink the beer instead!

There is also a theory spreading around the lawn care community that an alcohol spray can control leatherjacket numbers. The theory behind this is that the grubs do not have a liver and as such posses no ability to digest alcohol. It is an interesting theory and I am running a test (spring 2019) to see if there is any truth in it. Spraying beer over your lawn may sound crazy, but there may be some sense to it. Getting them to drink it in sufficient quantities will be the hard part!

Beer spray for leatherjackets
Beer in my sprayer!

Leatherjacket controls to avoid

Some sources recommend rolling your lawn to compact the soil. The theory behind this is that it prevents the leatherjackets from moving through the soil and feeding. However I DO NOT recommend this for a domestic lawn. The resulting damage to the structure of the soil caused by compacting will be just as bad as a leatherjacket attack! Rolling your lawn is never recommended.

Also some professional lawn care companies have been offering to discretely spray lawns with their old stocks of banned insecticides. I cannot stress enough how bad this practice is. It is illegal to even hold stocks of these banned chemicals, let alone knowingly spray them as part of a business exchange. Both parties involved could get into some serious legal trouble if it was found out. If your lawn care company offers this, simply decline.

Will leatherjackets keep attacking my lawn?

Leatherjackets grubs are an annual lawn pest. Once they have turned into adults and flown away the lawn can be repaired. Your lawn may become re-infected with crane fly larvae from the next generation. I have seen lawns get infected in one year and never since. I have also seen lawns become infected several years in a row. It is just the random nature of these insects of where they happen to fly, mate and lay eggs. One you have confirmed that your lawn has leatherjackets, it is best to be vigilant every year so that you can minimise any damage and take action quickly.

If you have any success with any of these controls, or have any other ideas or suggestions in keeping their numbers down, I would love to hear about it. Get in touch or ask a question.

Kris Lord
The Lawn Man

Additional reading references

Additional photos of leatherjackets

Leatherjackets lawn damage
Leatherjackets lawn damage
Four leatherjacket grubs
A selection of leatherjacket grubs compared to a 50p piece.

Alternative search terms for leatherjackets:

Leatherjackets have also been called: leather jackets, leather backs, leather back grubs, grubs, european crane fly, true craneflies, true fly

From The Lawn Man Website Archive:

25 thoughts on “Leatherjacket Lawn Pests – The Complete Guide

  1. Tony Forster

    Hi Kris,
    Have found all your replies and info really useful
    Our lawn has suffered badly from leather jacket damage for the past couple of years needing extensive repairs, turf and reseesing.
    Nematodes just don’t seem to work.
    Probably will do the black sheeting removal option but was wondering what time of year should this be done? Or is it necessary to repeat periodically?

    Thanks
    Tony

    Reply
    1. Kris Lord Post author

      Hi Tony,
      Use the black sheet method over the winter and into spring where damage is being done.
      Being vigilant and active over the winter months can prevent your lawn being destroyed in the spring.
      Thanks for reading.
      Kris

      Reply
  2. Jim Lewis

    Hi Kris,
    We have now removed all the grass from a 25 sq metre area along with well over 1000 leatherjackets. However, when we dig down to a depth of 4-6 inches we are still finding lots more so our current plan is to rotavate the area this week to clear as many more as we can find with a view to then reseeding a new lawn.
    It would be helpful to understand the best timings from here to sow new seed that will also give us the best chance of avoiding a repeat attack. Should we re-seed immediately or should we now wait until after any crane flies have stopped laying eggs this time around? Do they actually lay their eggs on the soil or do they find grass to lay their eggs?
    Any guidance would be gratefully received.
    Cheers
    Jim

    Reply
      1. Paul Clarke

        What time of year is the best to use the black sheet system please?

        Reply
        1. Kris Lord Post author

          Hi Paul,
          When the leatherjackets are in the soil and feeding. Usually mid winter into spring.
          Regards
          Kris

          Reply
  3. Chris

    Hi Kris,

    I had a very disappointing discovery this week. Having thought that multiple nematodes treatments early spring had cured my Leatherjacket infestation, sadly this week brown patches have started to appear all over my 100 sqm garden. Did some investigating this morning by digging some test holes and low and behold they are back!
    I have never tried the black plastic method so I will be trying that. Well, I h e some black garden membrane some hope that will do the trick as I want to cover large areas in one go.

    Cannot tell you how disheartening it was to discover them I. The lawn this morning as in previous weeks the lawn was looking really healthy and green.

    Fingers crossed the black covering will reduce numbers to a manageable number and the lawn can hold them off until autumn.

    One question though, would starving the lawn of water for as long as possible help kill the leatherjackets?

    Thanks
    Chris

    Reply
    1. Kris Lord Post author

      Hi Chris,
      The leatherjackets won’t have ‘returned’. They never left. Nematode treatment is an organic control and as such will rarely control 100% of the pests. They will have been in your lawn all winter.
      If the lawn was previously looking healthy and green then they will not have been doing much damage and the lawn was recovering quickly.
      It’s not worth trying to get the remaining pests out now (June) as they will soon pupate and leave the lawn. Let their life cycle complete and then look at controlling numbers for next year.
      Starving the lawn of water will only harm the grass. Not a good idea at all!
      Thanks for reading.
      Kris

      Reply
  4. Mark

    Great article, I can see the damage on my lawn over the last few years is Leather Jackets.
    It’s now mid June, I am going to try and treat the lawn with nematodes, although it does say this is not the best time as their skin is too thick, I hope it will kill some and them, then I can work on the grass and give them another dose in September October. Would the black bag method still work now or are they at a different life stage and not surfacing? I can see it’s only certain areas that are damaged, but will they be all over the lawn even in the good areas with no damage.
    Thanks

    Reply
    1. Kris Lord Post author

      Hi Mark,
      There really isn’t any point in treating with nematodes in mid summer. The main window of damage has passed and most of them will be preparing to pupate now anyway, leaving none to kill!. You will just be wasting your money.
      Keep them in the fridge for application as a preventative when conditions are correct later on in the year.
      Regards
      Kris

      Reply
  5. Hayley

    Hi, thanks for the useful information, we have a large infestation of Leatherjackets this year especially! We have used the black sheet method over the past couple of days. Our garden is 30m2 and after covering only half of the garden with plastic sheeting, we picked off by hand over 500 leatherjackets!!!!
    The other half is covered at the moment and we will remove and check in the morning, after removing the dead grass and roots we are pretty much back to bare mud 🙁 I have ordered Nematodes and will double dose the ground after we have removed as many by hand. Then we plan to lawn seed, do you think this is the best way to do it or shall we wait a little longer before seeding the lawn?
    Many thanks

    Reply
    1. Kris Lord Post author

      Hi Hayley,
      Well done on removing so many!
      There is not much point in applying nematodes after the grubs have been removed. You would be better off storing them and applying them in the autumn a couple of weeks after the summer adults are flying.
      You can seed the lawn as soon as you feel most have been removed.
      Thanks for reading.
      Kris

      Reply
  6. Suzie

    Hi,
    Thanks for the information, it’s really useful.
    I have just discovered we have a leatherjacket issue in the garden so am going to try the black sheet method to get some of them out. I am just a bit unclear about how to destroy the grubs when the sheet is removed, as I have read on other sites that they can go back into the ground when you remove the sheet? Do you have to be really quick? I am wondering if can rely on birds to do the job quick enough.
    Secondly, we have quite a few bare patches that red reseeding, can this be done after we have done the black sheet method? I am also planning to use a nematode in Autumn to help prevent the same problem next year.
    Thank you in advance

    Reply
    1. Kris Lord Post author

      Hi Suzie,
      The grubs are not that quick, probably slower than worms! They can be easily picked off by hand. Of course if you leave them they will try to escape eventually. If you don’t have a local bird population, pick them off and dispatch them however you see fit.
      Yes, Re-seed the lawn after the population has been reduced. This will prevent the new grass from being eaten again.
      Leatherjackets in your lawn? Follow these steps …
      Nematodes may help, but I would not rely on them. Vigilance is key during the winter.
      Thanks for reading!
      Kris

      Reply
  7. Louise

    Hello my garden was lovely & green last year it’s now just mud , my granddaughter plays out side what’s the safest thing to put down to get rid off them …. many thanks

    Reply
  8. Laura

    Hi
    I have some garlic liquid Regel G.
    Also have netted the entire lawn. Was thinking g of applying the garlic about now? Is this too early do you think?

    Reply
    1. Kris Lord Post author

      Hi Laura,
      A garlic spray is generally intended as a deterrent to prevent grub eating vegetative matter by giving them an unpleasant taste.
      September is too early as the grubs have probably not even hatched yet, let alone started feeding. I would leave it until much later on in the year.
      Regards
      Kris

      Reply
      1. Laura

        Hi Kris
        Ok that’s great. I have over netted my lawn and had eliminated over 1000 so far. ( plus prevented new ones entering my lawn) There are more males than females, so maybe my two years of nematodes worked with the females? Who knows?
        Today it is wet and around 100 have popped up out of the lawn 🙁
        I will spray 25ml to 5 litres of water and see what happens.
        Thanks for this advice.

        Reply
  9. Jill Hutchinson

    Hi,
    I have just found a leather jacket (very ugly i must say) on my decking, we do not have any grass in our garden so I was wondering if this beast is about to eat away and destroy my shrubs and flowers. I have never seen or heard of this bug before.

    Reply
    1. Kris Lord Post author

      It is unlikely to infest your pots, but they do eat roots of all sorts of plants. There are some other grubs though which can look similar which do like feasting on plants in pots, such as vine weevils. So vigilance on plant health is always key and investigate whenever there seems to be an unknown problem.
      Thanks for reading.
      Kris

      Reply
  10. Graham Troth

    Thank you Kris for replying. I found loads more at the surface this morning under the Black sheet. It’s so disappointing to see all this, but at least via your info on the website I can do things about it. Cheap beer was bought, actually it wasn’t too bad at 25p a can, ha!! I will do what you have suggested and keep you informed. Many thanks Kris, cheers Graham

    Reply
  11. Graham Troth

    Good afternoon Kris,
    I hope you don’t mind me getting in touch? Thankfully I doing your website yesterday. I have two lawns, not big but I am proud of them…until now. The past fortnight I could see there was something wrong. And looking at your info it’s leather jackets! Before my very eyes the grass was turning coarse and dead looking. I did what you said and put a dark piece of plastic over night…and behold they they were. I have aerated all the lawn, used my electric scarifier and cut low, it looks so sad now. My wife has gone out for some cheap beer too, ha! Tonight a have another piece of plastic to cover it all for two days. With that done Kris what are my next steps? I have some seed, also some lawn sad plus so wetting agent.
    I would love some advice now?
    Many thanks, you have saved me so far some heartache.
    Cheers Graham

    Reply
    1. Kris Lord Post author

      Hi Graham,
      Thanks for your comments.
      For now, I would continue to work on reducing the numbers of leatherjackets. Continue to try the black sheet method over different areas of the lawn and certainly look at applying a nematode treatment in the autumn as an organic control. A garlic spray can also be effective.
      As for repairs, overseed the lawn in the autumn and cover the seed with a dressing.
      I would then be vigilant over the winter and hopefully the lawn should make it through without any further damage.
      Thanks for reading.
      Kris

      Reply

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