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Chafer Grubs in my lawn
In our line of work, we deal with a variety of garden pests, but none are more dreaded than the chafer grub. Abandon hope, all ye who find grubs in the lawn.
If who haven’t heard of Chafer Grubs, then it really is time to listen up. For those poor souls who have had the misfortune to deal with these nefarious noshers in your lawn then you have our abiding sympathy…Yes, we are referring to Chafer Grubs!
So now we have your attention – what are they?
Chafer Grubs are the larvae of the Chafer Beetle and can cause severe damage to lawns or any grassed area. The small brown Chafer Beetle only survives for 2-3 weeks once reaching maturity and are harmless as they don’t cause any damage to your beloved lawn. However, when they are still in grub stage, the larvae can be as destructive as a bored child. They spend most of their lives in the soil feasting on the roots of the grass during Autumn and Winter before emerging as grown beetles in the Spring.
Of course, Chafer Grubs are not all bad. They are the staple diet of rare Bats and the equivalent of a Steak & Chips dinner if you are a Badger.
How can Chafer Grubs damage my lawn?
The short answer is very badly. Chafer Grubs cause damage to lawns by feeding on the root structure of the grass itself. This can go unnoticed for weeks or even months, as all the damage is under the surface. The problem is usually only detected when natural predators such as badgers or birds tear up chunks of the weakened turf. This activity in itself can cause significant lawn damage; a hungry badger can quickly plough through a lawn and leave it in a right sorry state!
Sometimes the grubs are also be discovered when renovation work is being carried out on the failing lawn.
How can I tell if I have chafer grubs in my lawn?
As mentioned above, the gradual weakening of the turf may not be overly noticeable at first. However as natural predators start tearing up the lawn, the large patches and clumps left behind can be the first indicator. Due to the damaged roots, a chafer-infested lawn may be more prone to drying out too.
If you suspect there are grubs, you can tear back a section of weakened turf and find them present just under the surface. The turf should lift back easily due to the damaged roots, and if they are present there will be fleshy white grubs with brown heads, which can grow up to 3cm long. In general, lawns on sandy or light soil tend to be more susceptible than those on heavier soils.
Is there anything I can do to control or deter Chafer Grubs?
Since the removal of pesticide control in 2016 there was little to control Chafer Grubs other than entomopathogenic nematodes, which are difficult to successfully apply and only have limited success. In July 2023 a new pesticide product, Acelepyrn, was licenced for professional use in the UK for the control of Chafer Grubs and Leather Jackets.
Acelepryn can be applied by a qualified lawn care technician following an Integrated Pest Management assessment, which is likely to involve a specific time frame for successful application and the recommendation of scarifying prior to use to remove any thatch barrier which will prevent the product reaching the target.
Prevention is always better than cure, and after years of experience, Lawntech have found that chafer beetle traps can also be a way of breaking the Chafer Grub cycle – the more beetles you catch, the fewer eggs laid on your lawn. Simply hang a trap in the garden at the end of April and leave it hanging though to June. A pheromone lure is supplied with the trap which lasts for approximately 6 weeks with replacements lures available. Chafer Beetle traps can help reduce the number of active beetles when they start to emerge during May. Again, these can be purchased online or from garden centres, or directly from us if you are a Lawntech customer.
How can I repair a lawn that has suffered chafer grub damage?
If your lawn has a persistent Chafer Grub problem or a severe infestation, it means the lawn ideally needs to be replaced.
Before embarking on any major repairs or replacement by re-turfing or seeding we would recommend doing your best to ensure the grubs are clear from the lawn to make sure your hard work is not in vain.
Take the following steps before checking out our turf laying guide or engaging the services of a lawn care or landscaping company.
- Step 1 – Kill off the lawn with Glyphosate herbicide to remove the food source for the Chafer Grubs, (this should be done by a qualified tradesman) or dig over the area to completely remove grass and weeds.
- Step 2- Rotovate the area to a depth of 100-150mm to expose the grubs so that natural predators can easily feed on them.
- Step 3 – Leave the soil open and fallow in a rotovated state for several months, or as long as it takes for the grubs to die or be eaten by natural predators.
- Step 4 – Double check that all grubs are gone before preparing the soil for seeding or turfing.
- Step 5 – Give the soil a final rotovation and rake down to create a fine, smooth, even tilth.
- Step 6 – Sow lawn Seed or lay lawn turf to create a fresh new grub-free lawn.
