Nemasys Leatherjacket Killer 100 sqm

(18 customer reviews)


Quantity Price
1 £16.99
2+ £15.99
4+ £14.99

Control leatherjackets naturally by treating with Nemasys® Leatherjacket Killer containing millions of natural nematodes – mix with water and apply the nematodes (Steinernema Feltiae) to the infected lawn with a watering can, EasyNem Applicator or Nematode ApplicatorIt is best to treat in the Autumn i.e. Sept/Oct/Nov as this is when the leatherjackets are newly hatched, the soil is warm (needs a daytime soil temp of 10c) and are at the most susceptible to the nematodes. You can treat at other times of the year i.e. NOW, but you must treat at DOUBLE STRENGTH as the mature leatherjackets are much harder to kill. Nemasys Leatherjacket Killer is a perishable product, which will keep for up to 2 weeks in the fridge, so please order when you are ready to apply. Nemasys® Leatherjacket Killer treats 100 sqm in the Autumn or 50 sqm when applied at double strength. N.B. Available NOW or pre-order for delivery in the AUTUMN by entering a future date below.

N.B. Need a Coarse Rose, EasyNem Applicator, Hose-end Feeder or Nematode Applicator – Add one to your basket and save £1.00 off a Coarse Rose, save £2.00 off a EasyNem Applicator or a Hose-end Feeder or save £3.50 off a Nematode Applicator when bought with your nematodes (savings applied at the checkout).

Special Offers – Help you lawn recover from a Leatherjacket attack

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Full Description

Daddy Long LegsCrane flies or daddy long legs lay their eggs in the same area of lawn from which they emerge, so numbers increase rapidly. These eggs hatch in August / Sept and the larvae immediately start to feed on the grass roots. The leatherjackets will feed though the autumn, before overwintering. They start feeding again the following spring and gorge on grass roots before pupating to emerge as adults in August. The symptoms of an attack are that grass growth slows and yellow patches appear PLUS the grass easily pulled up with little or no root growth. One of the biggest indicators of an infestation are birds, particularly starlings, which will pull at the lawn (causing even more damage) in search of the leatherjackets to eat.

LeatherjacketsLeatherjackets – In August, customers report clouds of daddy long legs emerging from lawns in early morning leaving behind the casings sticking up in the lawn. As the daddy long legs emerge, they start to lay their eggs back in infected lawns starting the whole cycle again – the next generation of leatherjackets hatch within 2 weeks. Leatherjackets are up to 2.5cm / 1″ long, greyish black in colour, legless and with no distinct head. We recommend treating with Nemasys® Leatherjacket Killer in late autumn i.e. Sept / Oct / Nov when the leatherjackets are newly hatched, close to the surface and the soil is warm and the leatherjackets are the most susceptible to the nematodes. You can treat during the rest of the year, but you need to apply the treatment at double strength.

Control leatherjackets naturally by applying Nemasys® Leatherjacket Killer containing millions of nematodes (Steinernema Feltiae) to the infected lawn as soon as the leatherjackets are discovered (and the soil temperature is 10c) or when the leatherjackets are active i.e. in the autumn (Sept / Oct / Nov) and in the spring (April). Nemasys® Leatherjacket Killer is effective at killing leatherjackets, but is harmless to children, wildlife and pets and the lawn may be used immediately after application. Apply as follows :-

  • Apply Nemasys® Leatherjacket Killer in Sept/Oct/Nov – This is the ideal time to treat as the soil is warm PLUS the leatherjackets are newly hatched, the soil is warm (needs a daytime soil temp of 12c) and are the most susceptible to the nematodes, so if you have had leatherjackets in the past or have discovered a leatherjacket infestation or your neighbours are infested and you want to keep them at bay, treat in Sept/Oct/Nov. When applying in the autumn, each pack will treat 100 sqm. Pre-order for delivery in September.
  • Apply Nemasys® Leatherjacket Killer when leatherjackets are discovered – Nemasys® Leatherjacket Killer is normally applied in September as this is when the leatherjackets are newly hatched and most susceptible to the nematodes, but if you have discover leatherjackets (not daddy long legs) at any other time of year i.e. in the spring/summer then treat at double strength as the mature leatherjackets are much harder to kill, but you must treat in September as well. When applying in the spring / summer at double strength, each pack will treat 50 sqm. Available ALL YEAR ROUND.

How to apply? – Nemasys® Leatherjacket Killer is easy to use. Simply mix the harmless powder with water & apply to the lawn using a watering can fitted with a rose (we recommend the Haws Rose no.14) or use a hose-end feeder / easynem applicator or nematode applicator for larger areas. Nemasys® Leatherjacket Killer should be applied to a moist lawn (we recommend pre – watering) on a dull day or in the evening. After application you MUST wash the nematodes into the lawn by watering heavily with a hose or a sprinkler. Once applied the nematodes will seek out the leatherjacket larvae and on contact they enter the larvae and destroy it. Having destroyed the leatherjacket ,the nematodes multiply and are released back into the soil to hunt down more leatherjackets.

How is it sent? – Nemasys® Leatherjacket Killer is a perishable, living product, so it is sent out fresh by Royal Mail 1st class post. Being a perishable, living product, it must be used before the expiry date (which is marked on the inside of the pack and will be at least 2 weeks) and it must be stored in the fridge until it is needed. Once opened, the contents do not keep, so it must be used in one day – do NOT store the made up solution or powder.

N.B. Need a Coarse Rose, EasyNem Applicator, Hose-end Feeder or Nematode Applicator – Add one to your basket and save £1.00 off a Coarse Rose, save £2.00 off a EasyNem Applicator or a Hose-end Feeder or save £3.50 off a Nematode Applicator when bought with your nematodes (savings applied at the checkout).


  1. Ian Flockhart (verified owner)

    After losing an entire lawn to Leatherjackets in 2016, I started using the Nematode product twice a year. Since then my lawn has been untouched. This year I had an additional problem with large numbers of very large slugs. Once again Green Gardener provided the cure.

  2. Stuart (verified owner)

    Ordered Nemasys Leatherjacket Killer at a good price and delivered within 2 days, great service.

  3. Eleanor (verified owner)

    Didn’t really expect the product to work however it seems to have done the job. Have only seen one live leatherjacket since applying the product.

  4. Ian (verified owner)

    Was a bit late in ordering Nematodes but ‘Greengardener’ had them to me before you could say leatherjacket! Excellent service and price for ordered product, goodbye Cranefly, hello healthy lawn.

  5. Christopher (verified owner)

    Very good service yet again from green gardener, the Leather Jacket Nematodes easy to order, arrived on date, well packed and easy to use. This is an annual exercise for me, so far so good.

  6. Graham (verified owner)

    Prompt service in supplying nematodes to control leatherjackets. It’s proved very effective.

  7. Chris (verified owner)

    Excellent product, did the job. speedy delivery. I am very satisfied and pleased.

  8. Anonymous (verified owner)

    Bought leatherjacket nematodes again from Green Gardener. After postage charges, theirs are the cheapest and most reliable I found. Delivery is quick and efficient. Exactly what I ordered and arrived a little faster than expected.

  9. Ian (verified owner)

    I started using Nemasys Leather jacket treatment five years ago after losing an entire newly laid lawn to leatherjacket infestation. Absolutely zero problems since then. Deliveries are always prompt and instructions accompanying the product are very clear and easily understood.

  10. Philip (verified owner)

    Easy to order online and received order very quickly. Nematode treatment has worked!

  11. Anonymous (verified owner)

    Ordered nematodes to combat the leather jacket attack on our lawn, a two dose autumn treatment, one pack now and a second pack delivered a few weeks later. Received each packet in good time and good condition. Followed the clear and easy to understand instructions and we seem to now have a recovering lawn, it may take some time and a little re-seeding but hopefully the problem is resolved. Excellent service and pleasing result so far.

  12. Surendra Patel

    This is the first time I am ordering and will use for the first time

  13. Mrs N Dower

    Great stuff!

  14. Ian

    Hello Jon, I’m just emailing to let you know how pleased I am with the result of applying the nematodes (purchased from Green Gardener) last autumn. The change in my lawn has been remarkable. I’ve also put a black plastic sheet down in a few areas to see if any leatherjackets appear – and I’ve only spotted one (I think). A great result. Thanks again Ian

  15. Elaine (verified owner)

    I used this in Spring 2021 as I had moved into a new house with a heavy infestation, which I discovered on creating new borders where the young plants were being destroyed. I was delighted at the result and after using Nemasys Leatherjacket Killer my garden has been transformed and the lawn has recovered also. I will be placing an order soon to treat my garden in October. I’m very happy with the service provided by Green Gardener.

  16. AntonioCip

    Nemasys Leatherjacket Killer should be applied when the soil temperature is above 12oC 54oF and the leatherjackets are at the correct stage in their life cycle. This will be late August till the end of October. An easy way to judge the correct time is to apply two weeks after a large number of crane fly are seen.

    • Jon

      Thanks for the comment and we do recommend treating in Sept / Oct as you suggest, BUT if your lawn is under attack at other times of the year i.e. in the spring / summer, then you can still treat with Nemasys Leatherjacket Killer but you HAVE TO apply at double strength as the leatherjackets are more mature and much harder to kill. This is why it is available all year round.

  17. Edward Watson

    Have used this company several times and have always had excellent service. I have been buying Nemasys Leatherjacket Killer and the product has been working well. Also competitively priced.

  18. Jon (verified owner)

    Ordered the leatherjacket nematodes and they arrived quickly and worked – thanks!

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