April 13th, 2018 by
If you pride yourself on your lush, green natural lawns, then chafer grubs might well be your arch-enemy. They’re the offspring of the otherwise harmless chafer beetle (commonly known as June bugs in the States). These pests live underground and feed on grass roots, meaning your nicely-tended lawn is like a permanent breakfast in bed for them! They’ll also lay their eggs there, and when those grubs hatch they live underground for months eating – you guessed it – the roots of your grass! Naturally when the root dies, so does the grass. It’s literally the root of the problem! If you only have a small number of grubs in your lawn, you don’t need to worry. Your grass growing will likely cover any damage caused by chafer grubs. If you have a large infestation though, the sheer quantity of these critters combined mean that they can devastate a lawn in a matter of months. To make matters worse, the chafer grubs are a delicious snack for birds, foxes and a variety of other animals, all of whom will happily dig up your garden to get at these plump white grubs! Unlike a lot of other pests, you’re never really safe from them, as their long life cycles mean they essentially feed all year round, lay eggs then die, and the cycle begins again.
So what are the signs I might have a chafer grub problem?
Your lawn will start to look noticeably sparse or it may appear blotchy and yellow before disappearing altogether. As chafer grubs spend a lot of time feeding from autumn right through to late spring, many gardeners just assume it’s an unrelated winter disease. By the time they realise what’s really going on, it could be too late! If you’re noticing a lot of birds pecking away at your lawn, and you haven’t put any food out there for them, that’s a dead giveaway. If you find any patches of loose turf that have been dug up, check the soil underneath. You might find some grubs there! Chafer grubs feed right through the autumn Another way of teasing out grubs is to make sure you water your grass regularly. The critters love moist soil and will make their way upwards towards the surface if that’s where the water is. Unfortunately, that’s about it. One of the reasons chafer grubs are so problematic is that it can be hard to know whether you even have them until your lawn is damaged beyond repair. Regular maintenance is key – keep a very close eye on your lawn from summertime onwards. If you notice it starting to look sparse, investigate further.
How do I get rid of chafer grubs?
That’s the kicker. There are very few ways of getting rid of chafer grubs, none of which are perfect. Even if you were happy to use chemical pesticides, there currently aren’t any available legally that work on chafer grubs. You could invest in nematodes – these are naturally occurring parasites that latch onto the grubs and kill them. They are very effective for getting rid of chafer grubs, and they don’t harm any of your plants or any other creatures. However, they aren’t cheap, so if you’ve got a decent sized lawn expect to pay upwards of £60 to get enough nematodes to do the job. Also, nematodes are living organisms, so it’s not like you can buy them and keep them in your cupboard for ages just in case. They need to be used within a few weeks of purchase, or they’ll die. Another option is a naturally occurring pesticide, like neem oil. Be very careful when searching through natural remedies though as they can often have unintended impacts on your garden. Neem oil, for example, does a great job of killing lawn grubs like the chafer, however unlike nematodes it can also kill creatures that are good for your garden, like bees and ladybirds. Be very wary of when you apply it if you go this route – make sure you do so at night when bees and the like are sleeping! You can always just re-sow your grass that’s been damaged and hope the chafer beetles don’t come back to lay eggs. It isn’t quick or efficient, but there is a chance the beetles will lay their eggs elsewhere the next year.
Sounds tough. How can I avoid them in the first place?
Prevention is always better, cheaper and easier than the cure. Every method of getting rid of chafer grubs has some significant drawbacks. Regular maintenance means a stronger lawn, which means it’s easier to stave off infestations. Strengthening grass with iron sulphate is a far more cost-effective method of dealing with chafer grubs as it reduces the chances of you getting them in the first place. This is because it raises the acidity of your grass and soil slightly, which the grubs don’t like. Even if you don’t completely prevent chafer grubs, it’s highly likely iron sulphate will ward off enough that you’ll prevent a full-blown infestation. Being a nosy neighbour also helps. If you notice your neighbour’s lawn is in a sorry state, be on the lookout. It’s highly likely the beetles will be after some fresh new grass to lay eggs under when mating season comes! It can be disheartening to see your green grass replaced by bare brown soil, particularly if you’re new to gardening, but a bit of preparedness goes a long way in preventing this.
Ray Price says:
Oct 16th, 2018 at 4:16 pm
We have a cookery where the birds live and sattack our golf course making a very bad news of many area's of the course do you have any answer please Regards Ray Price Grange Park Golf Course
Chris Chapman says:
Oct 17th, 2018 at 9:25 am
Hi Ray, It sounds like you may have some grubs so it's worth checking what kind of grubs are under your lawn. Cut out a C-shape in your lawn and check underneath the turf for chafer grubs or leatherjackets. Once you've discovered what grubs you've had, I'd recommend picking up some nematodes to get rid of them and follow it up with some iron sulphate through the summer to prevent them from coming back. There are different kinds of nematodes for different grubs, so make sure you look for the right kind depending on the grubs you find. It's tricky but this should get rid of the grubs and stop birds from going after your golf course.
Sue Reveley says:
Oct 20th, 2018 at 8:32 am
Hi I have Chafer grubs in all my plant pots eating away all my expensive plants ! What can I use I am about to try nematodes but is it too late in the season ? And is this ok for my plants ?
Mrs Bernie Burton says:
Jun 19th, 2019 at 9:08 am
I have a paddock of about an acre and they have infested the whole paddock !! If I just leave it will it ever come back to life and do I have to move my horses?
Chris Chapman says:
Jun 24th, 2019 at 8:56 am
Hi Bernie, Sorry to hear about your problem with chafer grubs! If your grass is weakened but still alive you may be able to revive it with water and fertiliser. If it's dead with a lot of bare patches, you'll need to sow some new seed. In either case, we'd recommend keeping horses off the area until the grass recovers. Use lots of water and iron sulphate on your lawn until it's healthy - this will make your soil more acidic and will help deter chafer grubs, but it'll also help your grass fight off any returning chafer grubs in future. Hope this helps, good luck with your lawn recovery! Chris
Peter Marks says:
Sep 16th, 2019 at 8:19 am
I have read that neem oil cam be used. It needs to be sprayed on grass once a month in the Summer. Looks like even more in May - July when the grubs come to the surface. There is no immediate effect but over time (years) it will reduce the grub population. Also try getting a pair of lawn aeration spiked shoes and once a week walk the lawn. This has been tested by a universtiy and can kill up to 50 per cent of the shallower lying grubs.
Jean Winsland says:
Sep 27th, 2019 at 4:06 pm
Will iron sulphate damage bushes when I use it to discourage chafer grubs?
Chris Chapman says:
Sep 30th, 2019 at 9:41 am
No, it shouldn't damage your shrubs unless you use far, far too much of it. In fact it might help them grow even better and prevents diseases too!
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