23 September 2022

Customer Question – What is happening to my lawn?

Q. “I had a new lawn laid in July 2020 and looked really lovely for the first 18 months or so. However, I noticed some patches around February of this year but waited for a couple of months before using a lawn repair product but it made no improvement. Since July it appeared to be losing its colour and became bleached looking, but even more worrying Magpies have been digging it up and more than 3/4 of the lawn has gone. I have tried the garlic/chilli mixture spray but it’s absorbed and they keep coming. HELP, not sure what nematode to try?” Valerie

A. Thanks for the message and it does sound like you have a pest attack going on. Normally when a lawn has been turfed Leatherjackets are more likely (they can be imported with the turf), but magpies are more associated with Chafer Grubs. We need to try and work out which pest is causing the problems as the nematodes are specific to each pest. Try lifting a small piece of turf where the birds are pecking and see if you can see any pests. They should be close to the surface and not too hard to find – that is why the birds can hear them and are trying to find them. You will either find :-

• Chafer Grubs are creamy coloured, approx 1.5 cm in length, have distinctive legs and will be found in the grass roots. Chafer Grubs attack the grass roots causing the grass to yellow. Spotting the adult chafer beetles will help you to identify the pest responsible for the damage, BUT always inspect the lawn for the grubs to be sure. Birds (magpies and crows), foxes &/or badgers attacking the grass in an attempt to eat the grubs will cause even more damage and is often the 1st indicator of a chafer grub infestation. The Garden Chafer Beetle emerges in May/June from the lawn to mate before laying eggs in the lawn from where it has just emerged. These eggs hatch to produced chafer grubs. The eggs are often laid in the same place each year so the problem gets progressively worse. The Chafer Grubs feed on grass roots from July until late Autumn before burrowing deep into the ground to pupate. They are a source of food for large birds-crows and woodpeckers as well as foxes and badgers. These may do more harm to your lawn by ripping it up to get at the grubs. The Chafer Grubs then lay dormant during the winter deep in the ground before moving to the surface the following spring to emerge as beetles in May / June and starting the process again. If you discover Chafer Grubs, ideally treat with Nemasys Chafer Grub Killer in Sept / October.

• Leatherjackets are the larval stage of the crane fly or daddy long legs and they can quickly devastate a lawn. Crane flies or daddy long legs lay their eggs in the same area of lawn from which they emerge, so numbers increase rapidly. These eggs hatch in August / Sept and the larvae immediately start to feed on the grass roots. The Leatherjackets will feed though the autumn, before overwintering. They start feeding again the following spring and gorge on grass roots before pupating to emerge as adults in August. The symptoms of an attack are that grass growth slows and yellow patches appear PLUS the grass easily pulled up with little or no root growth. One of the biggest indicators of an infestation are birds, particularly starlings, which will pull at the lawn (causing even more damage) in search of the leatherjackets to eat. Leatherjackets are up to 2.5cm / 1″ long, greyish black in colour, legless and with no distinct head. We recommend treating with Nemasys® Leatherjacket Killer in late autumn i.e. Sept / Oct / Nov when the leatherjackets are newly hatched, close to the surface and the soil is warm and the leatherjackets are the most susceptible to the nematodes.

Let me know what you find.

Kind regards

Jon @ Green Gardener

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