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Leatherjacket Killer Nematodes - Steinernema Species

Treatment Size

What Are Leatherjackets? 

Leatherjackets are the larvae of Crane Flies, otherwise known as the Daddy Long Legs. These larvae cause damage to lawns by feeding on grass roots. This can lead to yellowing of the grass and patchy areas of lawn. Lawns will also suffer secondary damage when Leatherjackets are present, as animals such as badgers, or birds will attempt to feed on the larvae; and will rip up areas of lawn in the process.

What Are Leatherjacket Killer Nematodes & How Can They Help?

Naturally and safely control your Leatherjacket infestation with our Leatherjacket Killer Nematodes, which are deadly to the Leatherjacket larvae but safe to humans, pets and wildlife. Dragonfli Leatherjacket Killer contain Steinernema species nematodes that enter the Leatherjacket larvae via a natural opening, like the mouth, and feed on the pest from inside it. A natural bacterium is produced by the nematodes inside the larvae, which kills it. Infected larvae will be completely broken down by the nematodes. The nematodes also reproduce inside the larvae, releasing more nematodes into the surrounding area. 

When Should I Apply The Nematodes?

For optimum control over Leatherjackets, we advise using two applications of nematodes each year, once in the spring and once in the summer.

You should closely monitor soil temperatures and the presence of the adult Crane Flies (Daddy Long Legs) to time these applications. 

Spring Applications

Leatherjackets overwinter in the soil and can be present from February, or even earlier in certain weather conditions. We recommend applying nematodes in the spring when Leatherjackets have been observed in the soil, and soil temperatures are above 10℃. As a very general rule, with such varying weather in the UK, this will be normally be between February to April. Ideally utilise a soil thermometer to accurately gauge this, as soil temperatures are different to air temperatures.

Summer Applications

We advise a summer application based on the presence of the adult Crane Flies (Daddy Long Legs). You should apply your summer treatment approximately 10-14 days after seeing the adult crane flies emerge from soil. This should make applications most effective. This treatment should be applied usually between late August to early September. Summer applications are most effective as the soil is warmer which provides better conditions for the nematodes to locate the Leatherjackets.

How Many Nematodes Do I Need?

Leatherjacket Killer Nematodes are supplied in four pack sizes:

The 25million pack will treat an area of up to 50m2.

The 50million pack will treat an area of up to 100m2.

The 250million pack will treat an area of up to 500m2.

The 500million pack will treat an area of up to 1000m2.

If your lawn has suffered severely from Leatherjacket damage, and the number of Leatherjacket larvae within the soil is high, multiple applications of nematodes will be required to gain overall control. Consider applying Leatherjacket Killer Nematodes every 2 weeks in the summer period.

What Conditions Do The Nematodes Require?

Choose a humid or wet day to apply your Leatherjacket Killer Nematodes. Nematodes are UV-sensitive and will not survive long when exposed to bright, sunny conditions. Apply the nematodes early in the morning or early in the evening in order to utilise the optimum humidity levels. Avoid application in frosty conditions.

Soil temperatures should be above 10℃ for the nematodes to be active, if applying in the spring.

How Do I Apply The Nematodes?

To increase the effectiveness of your nematode treatment, we always advise you spike and scarify the lawn before application. If there are bare patches or poor grass coverage, spiking the ground is particularly important. If grass thatch is thick, scarifying the lawn is vital in aiding the passage of nematodes into the soil. The lawn also needs to be kept moist for nematodes to penetrate the soil and reach the Leatherjackets.

See also our Nemaflo carrier which will help aid the movement of the nematodes in the soil.

1. First open and empty the contents of your 25 million sachet of nematodes into a bucket or container of 2.5 litres of water and mix thoroughly.

2. Next, fill your watering can (fit with a coarse rose), or sprayer (hand held sprayers should suffice, with filters removed, or, if applying our 50sqm & 100sqm packs, use the Nema Super Sprayer for optimum nematode application) with the mixed 2.5 litres of nematode concentrate and add another 5.5 litres of water so you are left with 8 litres of nematode solution.

3. Finally, spray your lawn with the nematode solution.

Continue to keep the lawn moist for up to 2 weeks after application. Repeat these instructions for an introduction of a second nematode sachet application 7 days after the first application. Repeat applications may be required for severe infestations. Full instructions are provided on delivery. 

Can I Store Nematodes?

You can store unopened nematode packs in a fridge but it is best to ensure you apply your nematodes as soon as possible for the best results.

Leatherjacket Killer Nematodes are harmless to humans, and safe to apply to edible plants.

Repair Your Damaged Lawn With Our Lawn Grub Repair Boost

To aid the recovery, and boost the repair of your lawn that has suffered damage, try our Lawn Grub Repair Boost. This natural biostimulant helps roots regrow, and aids new grass growth. This will help negate lawn damage, and the boost can be used in combination with nematode treatments. Treatments can begin as soon as grass begins growing in the spring.

Customer Reviews

Based on 6 reviews Write a review

Customer Reviews

Based on 12 reviews

So amazed by how easy to use it is and results it has given to my grass in such a short time. Can’t recommend dragonfli enough.

Solved the problem

My lawn is looking great after the nematodes got rid of the leatherjackets

Colin Rust
Nematode Success

I used Dragonfli nematodes last year to remove the pesky leatherjackets that ran amok on my lawn. It was a great success and my lawn has recovered. I have purchased more for this year and will apply once the grass has come up to temperature. My neighbours have not been so lucky and the dreaded leatherjackets have returned to munch their grass away. I have recommended Dragonfli to them to get rid of them and hope they will use this product. Nematodes are an effective treatment for these pests and I recommend their use. Congratulations Dragonfli.

Geraldine Turner
Waiting for late summer

Our lawn was completely taken back to bare earth. We treated it with Dragonfli Nematodes and will have to leave them to do their work until later in the summer. However the delivery was very prompt and we managed to water them in with the outside temp above 10c. Thank you Dragonfli for your promptness - we will keep you informed.


Used it twice so far, seen a huge difference in my lawn, will be purchasing again this year