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Leatherjackets

Symptoms

Grass growth slows down and yellow, dying patches appear in the lawn. Dead and dying grass can be easily pulled up to reveal little or no root growth.

Find it on: lawns, strawberries, brassicas, some ornamental plants
Time to act: spring to autumn

Overview

Leatherjackets are the larvae of crane flies, or daddy-longlegs. The female fly lays up to 300 eggs in the lawn in late-summer. These hatch after a couple of weeks into grey-black, legless larvae that have a tough, leathery skin, hence the name 'leatherjacket'. From autumn through to summer, the larvae feed on the roots of plants, eventually growing to 5cm in length before pupating and emerging as adult flies in late-summer.


Solution

Grass growth slows down and yellow, dying patches appear in the lawn. Dead and dying grass can be easily pulled up to reveal little or no root growth.

Organic

After heavy rain or having thoroughly watered any yellow patches in the lawn, cover them with black plastic sacks and leave overnight. The leatherjackets will come to the surface and can be collected in the morning. Encourage natural predators, such as spiders and garden birds, especially starlings. Use the biological control Steinernema feltiae, which should be applied while the ground is still moist and warm in late-autumn.



Discuss this problem

Talkback: Leatherjackets
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pampam 24/11/2011 at 15:28

the above has been most useful
100's of larvae have been appearing
before i read the article i have been gathering them
myself and my neighbour are infested with them
now we can deal with the problem without hopefully having to deal with a new lawn, thank you

tonybarnett 24/11/2011 at 15:28

my lawn has appearance of being dead im many places and has been like this for last 2 months. . Nowmagpies are making a complete mess and digging big holes all over lawn.What can I do to bring back grass. If it means heavy scaryfing and reseeding what soil do I use to fill in the holes and uneven ground I have previously used lawn top dressing but it is so fine and dusty Can i use an insectide

Tony barnett

Bridgid Hess 14/05/2012 at 13:08

my whole lawn (100sq m) has died leaving only some moss behind. it was very luscious as i fed it lots during summer. it was laid three years ago. I assumed it is leatherjackets doing damage as roots have turned to soft fibrous compost (last year i had to really spike hard and this year spikes slid in no problem)i ordered nemesis but was away when it arrived and it sat for 2 weeks on my mat - i live in Scotland and it was cold with no heating on..... but i know it is supposed to be in fridge. i applied it last week and am not sure if it is going to be effective. it was like a soft brown cotton wool like substance - like candy floss. i raked the ground first and then re-seeded ground and covered with light covering of sand and soil.
how can i tell if it is effective? will it effect new seed? should i buy some more in case? it had an expiry date of end May on the box. I assume it has a very short shelf life?
thanks
Bridgid Hess