Chafer grubs are a nightmare for avid gardeners – particularly those with sweeping, perfectly kept lawns. Capable of causing serious damage to your green space, these lawn grubs are important to stay aware of just in case you happen to come across an inexplicably weak or straw-coloured grass area in your garden.
At Artificial Lawn Company, we have worked on a host of different outdoor projects, many of which have been triggered in response to lawn damage or discolouration. Utilising this experience, we have put together this detailed guide on how to get rid of chafer grubs, covering what they are, what damage they can cause and how to address the issue.
What Are Chafer Grubs?
Chafer grubs are one of a range of lawn grubs which feed on grass roots to survive. They are the larvae of the chafer beetle and they live within the soil, consuming roots and slowly growing in size until they are ready to emerge as adults.
In terms of appearance, chafer grubs are white, with a curved c-shaped body and a light brown head - not entirely unlike a maggot with legs attached! They vary in size from around 10 – 40mm, gradually growing as they age and eat. Typically, chafer grubs also have three pairs of legs, all of which are positioned close to the head and the end of their bodies are more grey than white.
As you would expect, insects which consume grass roots are unlikely to be healthy for your lawn, which is why identifying that you have a problem on your hands is essential.
What Are the Signs of a Chafer Grub Infestation?
Chafer beetles tend to lay their eggs during very-late spring and summer. When these eggs hatch, the chafer grubs slowly start consuming the grass roots surrounding them until they grow larger, much like many different beetle species. Due to this pattern of growth, you are most likely to identify a risk of chafer grub damage or infestation during autumn and spring.
In autumn, the larvae have begun to mature slightly and will be eating more readily, causing grass discolouration or death. Additionally, the grubs will be close to the surface of the soil, making them easy pickings for birds and other wildlife; therefore, if you notice your lawn is getting more attention from the creatures of the local environment, you might have a chafer grub issue.
During winter, the larvae will descend further into the ground for safety from the cold, which is part of why you are unlikely to see many signs during this time.
Then, finally, in early spring the chafer grubs will be in the final stages of their growth. At their largest, they will consume grass roots at an alarming rate, producing fast and potentially widespread yellowing or death. This will occur just before the grubs emerge as adult beetles, only to lay more eggs in your lawn and repeat the process.
If you notice any kind of pattern like this, particularly if it occurs annually and with regularity, you should seriously consider investigating the possibility of a full chafer grub attack.
What Damage Can Chafer Grubs Cause?
Generally, all lawn grubs cause a combination of two issues – grass destruction and wildlife attraction.
By eating the grass roots, chafer grubs will destroy your lawn from the inside out. The chafer beetle damage can become extensive if left untreated, particularly during early spring when the larvae are at their largest.
However, one of the less obvious but actually more notable issues is how this infestation affects the local wildlife. If your lawn is going through a chafer grub infestation, birds, pests and even foxes will be attracted by the promise of nutritious food. They will peck and dig up your lawn to access this source of sustenance so that even if the majority of your grass looks okay, it will be torn up by the animals in the surrounding area. Not only does this lead to an ugly, patchy lawn, but it can have a knock-on effect if the local wildlife attracts other predators or leaves waste in its wake.
Keep an eye out for increased wildlife activity in your garden to stay on top of this.
How to Treat Chafer Grubs
There are multiple chafer grub treatments which can work if you have identified an infestation or attack. Each one has its own advantages and disadvantages so whatever your budget or needs, you should find a solution which works for you.
Chafer Grub Treatment 1: Nematodes
The first and most common solution is to employ a chafer grub killer. In most cases, this is a diluted chemical solution which contains a specific species (Heterorhabditis Bacteriophora) of parasitic worm, or nematode. Sometimes referred to as roundworms, there are thousands of species of nematode in the world, each affecting different animals or plants and each with its own individual traits. In this case, the nematodes infect the chafer grubs with lethal bacteria and then reproduce, infecting more chafer grubs until all of them died.
Nematode chafer grub treatment is entirely safe for pets, children and the environment despite the intimidating name, there are just a couple of points to keep in mind if you want to use this method to address your concerns.
- Treatment should occur in Autumn, usually between August and October when the grubs are most active. Between April and May can also be an effective time.
- The soil temperature should be above 12ºC before application.
- The soil should be moist.
Aside from this, as with all treatments, it’s essential to follow the instructions on the box as each nematode treatment can differ. If these conditions have been met, you can use the following steps to apply your chafer grub killer:
- Scarify or rake your lawn to clear it of debris and thatch
- Spike the lawn’s surface to allow the nematodes to get into the soil more quickly
- Follow dilution instructions for your nematode treatment and apply it
- Re-seed your lawn to replace any of the damage caused by the grubs, wildlife or the scarification progress
Leave the nematode treatment to work for around two weeks before moving forward with re-seeding and next steps.
Chafer Grub Treatment 2: Complete Lawn Replacement
Alternatively, you can choose to completely replace your lawn and starve the grubs out of the soil. This method of chafer grub treatment is slightly slower than nematodes but works equally well.
Instead of introducing something to kill the larvae, removing the turf that they feed one will work just as well to kill them off. This Is particularly effective if you have thriving local wildlife, as the grubs will rise to the surface of the soil over time and will be eaten by the birds and other creatures in the area. To use this approach:
- Use weed killer or herbicides to kill your lawn. Follow instructions on how long to leave the herbicide based on the box’s instructions
- Remove and dispose of the dead turf
- Dig over the topsoil every couple of days to bring any grubs to the surface and make them easy pickings for the birds
- After a week or two, being preparations to lay new turf and begin your lawn anew
This method is quite labour intensive but can be the best option if your lawn has been severely damaged by the infestation or the local wildlife.
Chafer Grub Treatment 3: Artificial Grass
Finally, if you prefer to combine treatment with prevention, consider laying an artificial lawn. By following the same steps as above and removing your current lawn, you can successfully treat your chafer grub problems and then install artificial grass instead of natural turf. This will remove the foodstuff that chafer grubs rely on, preventing any future infestations whilst also offering improved durability, weather resistance, and weed resistance.
As experienced artificial grass suppliers and installers, the team here at Artificial Lawn Company are perfectly placed to offer a fast and easy installation experience. Synthetic grass is no longer the vibrant, unnatural green that many people think of when they imagine artificial turf, there are now blended colours and soft-touch memory fibres to make it look and feel just like the real thing.