More about Leatherjackets
Our recent blog post about the leatherjackets, which are wrecking lawns in Marden at the moment, has aroused a lot of interest, and since then more information has come to light, particularly about birds and leatherjackets.
We heard from Jan Day “I haven’t seen any daddy long legs recently but we feed the birds and we have masses of starlings who are always around and love eating the leather-jackets under the grass. We used to be absolutely inundated with craneflies when we first moved to Marden in the 70s. The starlings really go for fat balls and also kibbled nuts as well as the leatherjackets!!”
My first thought was - yes but then you have the lawn wrecked from underneath by the leatherjackets and torn up from above by the birds digging them up! Then I thought more carefully about a garden I know on the Millwood estate where the lawn in the back garden is being wrecked right now by leatherjackets. Last summer the front lawn was under attack by birds digging for leatherjackets and looked awful. However this year… the front lawn has completely recovered! Would that be because the birds had eaten them all?
Well, confirmation came last Tuesday when Dr Ian Bedford PhD, who is a entomologist recently retired from the John Innes Centre, gave us a (really interesting) Zoom talk about garden pests and how to deal with them - and, of course, the answer is let the birds feast on them. As a general rule, as Jan said, encourage starlings, crows, rooks, jays and magpies into the garden, by providing suitable food and water. Also keep the soil moist so that the leatherjackets stay close to the surface and are easily accessible to birds’ beaks. This is more effective than nematode treatment which is both hit and miss, and expensive. There will be some bird damage to the lawn, but it will recover better than re-turfing or re-seeding, because the new grass roots will not be well established, and therefore more susceptible to future leatherjacket damage.
Further investigation on the internet has revealed more information. If you are suffering from a bad infestation right now here are some things you can do:
turn over the soil to expose the leather jackets, this will encourage the birds.
water an area of affected lawn, cover it with black plastic, and leave for a night or two, for the the leatherjackets to come to the surface. Then either sweep or mow them up and dispose of them safely, or feed them to the birds. Repeat on a different part of the lawn.
try a garlic spray on the grass, here are some details. There has been successful experiments with this in agriculture.
Another recommendation is to act quickly when the crane flies are actually flying around. This is when the leatherjackets have pupated and emerged, with only one thing to do - mate and lay eggs in your grass, ready to create the next generation of leatherjackets. This is the time to closely mow the lawn to remove some of the eggs. Do this often and dispose of the clippings.
Good information about leatherjackets can be found here https://thelawnman.co.uk/leatherjacket-lawn-pests/#how-can-you-control-leatherjackets