14 April 2025

Customer Question – Chafer or Leatherjacket?

Q. “Hello, I have spoke with a lovely lady on the phone today about the issues I am experiencing in my garden at the moment.  I have been advised that it is chafer grubs by a friend of a friend, but before I purchase some treatment from you for it, I would like to you confirm that you believe that to be the case. I have attached some photographs of my garden for your experienced advice. I look forward to hearing back from you.” With kindest regards, Beth

A. Thanks for the message. Unfortunately here is no way to tell by looking at the damage. You would need to big up some of the bare patches (where they meet green grass is a good place to look) and see what you find. White creamy grubs are chafer grubs. Feel free to send me a picture of what you find. Kind regards Jon

Reply “Hello Jon, Thank you for your response and advice.  I have attached some photos of what I have found, please give me your opinion on what you believe it is and what the recommended treatment plan is for it.” Kind regards, Beth

A. Thanks for the message and it’s a good job you checked as these are leatherjackets and NOT chafer grubs. These are the larvae of the daddy long legs and they damage your lawn in the autumn and spring. Treat with Nemasys Leatherjackets Killer NOW and then again I the Autumn i.e. around Sept. The leatherjackets are much harder to kill at this time of year, so you do have to apply it at double strength i.e. our 100 sqm pack treats 50 sqm when applying in the spring, so make sure you order enough. i.e. to treat 100 sqm you would need to order 2 packs.  Once you have treated the leatherjackets, you can then apply fertiliser / Root Success to help the lawn recover and if needed you can re-seed bare patches. I hope this helps. Jon @ Green Gardener

Reply. “Thank you Jon, I really appreciate your response and help. To 5 litres of water how much of the 100 square metre pack to you mix with it? I assume a normal watering can with larger holes in the rose head will suffice?”

A. Thanks for the message and you make a stock solution in 5 litres of water and then you take 0.5 litres of this solution and add it to your watering can – fill it with water and apply to 5 sqm. Repeat another 9 times taking a fresh 0.5l of stock solution each time, so you make a total of 10 watering cans of nematodes, which treats a total of 50 sqm – remember you are applying at double strength at this time of year, so this is why you apply to 50 sqm. Yes a watering can with a larger hole rose is perfect. 1.5mm is the ideal hole size, so if you can “sacrifice” an old rose and maybe drill out some larger holes that works really well.

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