Nemasys Leatherjacket Killer (Spring / Summer 250sq.m)


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£80.99 (VAT incl.)
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What are Leatherjackets?

Leatherjackets are the larval stage of the crane fly or daddy-long-legs, they are are about 2.5cm (1" long), greyish black in colour, legless and with no distinct head (see pictures above).

Also known as Tipula paludosa (European crane fly) or Tipula oleracea (Marsh Crane Fly).


How can I control Letherjacket larvae?

Use Nemasys Leatherjacket Killer to deal with a leatherjacket infestation, without any of the precautions associated with harmful chemicals.

Nemasys Leatherjacket Killer is incredibly effective and is 100% safe for children, cats, dogs, other pets and wildlife. 


When can I apply Leatherjacket Killer Nematodes?

  • Autumn application - typically late August through to the end of October:

When you start to see the adult daddy-long-legs in your garden (towards the end of August) you will know that in a few days they will be laying eggs. These will hatch quickly; therefore aim to apply two weeks after you see the adults.

This is when the young leatherjackets are active in the soil and is when they are most susceptible to the nematodes.

  • Spring application - typically April to June / Summer Application - July to August:

If you have discovered 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 -  you must treat in autumn as well.

Where a severe LeatherJacket infestation is present, multiple treatments over an extended period (spring and autumn) may be required.

Leatherjacket lifecycle and application window

Tipula paludosa (European crane fly) Leatherjackets have one generation per year. The adults emerge from pupation from July to September and almost immediately lay their eggs (peak emergence can vary regionally). The larvae hatch out after about 14 days and start to feed on the bases of stems and roots immediately (this is when they are most vulnerable to nematodes), they become more active and feed voraciously in the spring when the soil begins to warm (the second opportunity to treat with nematodes but at double strength).  When fully grown they reach approximately 3-4 cm in length and then stay within their burrows for about 6-8 weeks before making their way to the soil surface to pupate and the cycle repeats. 


How do Leatherjacket Killer Nematodes work?

The nematodes (Steinernema feltiae), seek out the leatherjackets and attack the pest by entering natural body openings. Once inside, they release bacteria that stops the pest from feeding, quickly killing the pest.

The nematodes then reproduce inside the dead pest and release a new generation of hungry infective nematodes, which disperse and search for further prey.

Beneficial nematodes are living organisms, so they must be used before the expiry date (which is marked on the inside of the pack and will be around 2-3 weeks) and should be stored in the fridge until it is applied.


How do I apply LeatherJacket nematodes?

Prior to applying the nematodes:

  • Cut the grass short before treatment.
  • Soil should be between 10°C and 30°C during application and for at least two weeks after.
  • Irrigate the area to be treated prior to application in order to apply the nematodes to a moist lawn.

To avoid desiccation of the nematodes:

  • Avoid direct sunlight; make applications in the evenings or in dull conditions
  • Application during rain is highly desirable.
  • It is very important to irrigate immediately after application, water the grass well so the nematodes are washed below the thatch layer into the soil to reach the roots where the larvae will be feeding.
  • Ensure soil is moist for at least two weeks after application.

Leatherjacket Killer Nematode application instructions using a Hose-end Feeder (250 sqm pack) :-

  1. Divide the 250 sqm to be treated into 25 sqm areas.
  2. Divide the pack into 10 equal portions.
  3. Add 1 portion i.e. one tenth of the pack to feeder bowl. 
  4. Fill the bowl with water, mix thoroughly until fully dispersed and attach the hose.
  5. Set the Miracle-Gro® Feeder spray pattern to ‘flat’ and watering mode to ‘feed & water’.
  6. With the feeder in an upright position, apply evenly to half of the area using a side-to-side motion. Application will take approximately 8 minutes under typical water pressure conditions.
  7. To make sure the nematodes are adequately watered in, treat the same area again for a further 8 minutes if treating a vegetable patch or 16 
    minutes if treating a lawn. Applications to lawns require more water to wash the nematodes through the grass thatch.
  8. Repeat the procedure with the other 9 portions - treating each 25 sqm area.

Adhering strictly to the application timings will ensure that any remaining colour in the bowl will be due to the inert carrier only and that you have performed an even application.

IMPORTANT: Make sure the lawn does not dry out after applying nematodes and keep it well watered for at least two weeks.

Please note: Pack instructions are subject the change - if you have any queries regarding application, please contact us before application. 



Which pack size do I need?

To calculate your area measure the width and length of the area to be treated and multiply them by each other e.g. 10m x 25m = 250 sq.m


Leatherjacket Killer - Spring application must be made at double strength - therefore this pack treats 250 sq.m - even though the outer sleeve shows 500 sq.m.

Can't see an answer to your question? Please contact us and we will be happy to assist you.

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Excellent product. Quick delivery.