Chafer Beetle Larvae in your Lawn

If the birds and other mammals such as Badgers and Foxes are dining out on your lawn then this is one of the reasons why your lawn might be suddenly listed on the Egon Ronay 'Good Lawn Food Guide'....

What are they after?

Chafer Beetle Larvae are the larvae of the Common Chafer Beetle or more commonly known as the May Bug that can be seen flying around on warm early summer evenings. Chafer grubs are white, comma shaped, fleshy grubs with brown heads and 3 pairs of legs on the front segments of their body. Grubs live for 1-3 years before adult beetles emerge. Patches of dead or dying grass similar to that caused by leatherjackets are caused by the grubs. Early and correct pest identification is important

When a pest problem is suspected, the turf should be examined thoroughly to find the culprit. Pests are often found first in stressed areas, such as the edges of lawns or in shady or wet areas. They are not usually distributed evenly so it is advisable to look for spots that have discoloured, stunted or distorted turf. Insects tend to proceed outward from a central point; therefore they are generally most active on the outside edge. Part the leaves of the grass and look into the thatch layer.

Go on, be brave and set about exploring in the soil beneath the grass roots…

The larvae feed on the roots of grasses during the spring and summer. They cause yellow/brown patches and, as the grasses are eaten off at the same level, it may well be that a complete carpet of turf can be removed in tact. There are usually less numerous and less troublesome than leatherjackets but their presence is usually seen the first time the lawn gets stressed by cold or drought by the frenzied activity of large birds like Crows, Rooks and Magpies. The net result – no grass roots, no grass and a lot of ripped up areas once the birds have gone! The adults and grubs have many predators: birds, badgers, moles and even foxes and these cause damage to the turf areas when they are foraging for their food.Chafer Beetle Larvae live a little deeper the root zone than Leatherjackets which reside in the upper root zone. Get your garden or pen knife out and dig below the surface to locate some, preferably in an area that adjoins an area where the birds have been pecking. If present in the soil, you will discover the larvae in a little self made hollow in the soil. The eggs are laid in soil in the late spring by the adults in batches of 10 – 30.

What do the adults look like?

The adult Cockchafer is up to 35 mm long. It has a black thorax, rusty brown wing cases and brown legs, and the tail end of the abdomen is narrowly pointed. In side view, the abdomen has saw-tooth shaped patches of white under the edges of the wing cases. The fan-like tips of the antennae are particularly obvious in this species.

Control measures

There is little or any benefit renovating and repairing any damage to your lawn until you have killed the larvae. As Chafers live in the soil for up to three years you can have more than one generation in the soil at any given time. Control them by applying an insecticide as soon as you have performed a positive identification, usually in the growing season – April to September. Prevention is always better than cure so once one application has been performed, repeat annually in the if repeat outbreaks are common particularly in light sandy soil areas.

Amateur Control Measures - Visit this web link Provado Lawn Pest Killer

Professional Control Measures - Weed Free - Contract Pesticide Application Services

Pictures and part text copyright acknowledged – Bayer Environmental Science & The Royal Entomological Society.

A downloadable .PDF version Chafer Beetle Larvae is available here

Comments

[Barcelona Corporate Flats]

You raise a lot of questions in my head; you wrote an excellent post, but this post is also mind provoking, and I will have to think about it a bit more; I will return soon.

Reply - thank you. Come back soon

[Graeme Possnicker]

I live in the south of France and have found lots of these large white grubs in the soil and compost heap.They would appear to be the grubs of a beetle.Worse still ,I have found the living in the centre of some of my small palms in the garden and they have eaten the young growth and killed the plants.Would systemic insecticide be effective to remove them ?

[Bail Bondsman Los Angeles]

While this subject can be very touchy for most people, my opinion is that there has to be a middle or common ground that we all can find. I do appreciate that you've added relevant and intelligent commentary here though. Thank you!

[Craig]

Just found these all over my Lawn. Bit worried as have a Rabbit. Guess they shouldn't bother him but need to be able to treat without reverting to pesticides. Any ideas?

[Jude Roberts]

I am trying to identify the beetles in my garden. they appeared approx 3 days ago in the grass,the grass had just been cut. the beetles appear to be lively when the sun is out and fly around,they also look like they are constantly breeding. at night time they look as if they have gone and a lot have died but by the next day this is not the case and there are hundreds of them. the picture you have on here of the adult is exactly how they look.
if they are from the chafer grub how do i treat the grass when i have children and pets?
thanks,
Jude.

Answer - you have the young Chafer Beetles that have recently emerged from the lawn. They will soon be flying around, banging on the patio door windows. You cannot kill the adults when they are on the wing but you could purchase an adult catcher, a bit like a wasp watcher. Get them from http://www.oecos.co.uk/pheromone.htm. They worm on attracting the adults by the use of pheromones. In the autumn months, apply Bayer Provado and re apply in the middle of the spring before the adults emerge. The larvae have been feeding on your lawn eating the grass roots which will lead to stress. Fertilise the lawn. See www.thelawnshop.co.uk.

[Jackoviejo]

My lawn began to be torn up by crows 2 to 3 years ago. I found the white grubs when I repaired the lawn, but didn't know what they were. On returning from holiday a few days ago I discovered hundreds of beetles appearing all over the lawn whenever the sun comes out. This has been going on for several days now. At least I now know what they are and will take appropriate action.

Reply - Glad we were able to help. Tell your friends!

[Mike Seaton]

Hello, thanks you for comment and input, the grubs you have found may not be Chafer Grubs but the grubs that live in old rotten wood and trees. It would be sae to use the compost thouge as you could discard any that you spot in the process of moving the compost.

[L.ROTA]

I have found 20+ chafer grubs in my compost heap. If I take them all out will it be ok to use the compost?