How do I control Black Beetles in my lawn?

Author: Jon Lamb   Date Posted: 7 March 2018 

At last, a simple and much safer solution for controlling black lawn beetles.

During summer and early autumn, far too many Adelaide lawns are regularly bombarded with chlorpyrifos (an extremely toxic and environmentally damaging chemical) in an often futile attempt to control black lawn beetles and their witchetty grub-like larvae.

The alternative is to spray the lawn with a relatively new but very low toxic systemic chemical containing imidacloprid (Confidor, Bug Kill, Conquest and others). In this case, the aim is to kill the black beetle larvae in spring well before they begin damaging your lawn by feeding on their roots.

Black beetles overwinter in lawn grass before mating and laying eggs anytime during spring. During late spring and early summer, the overwintering generation of beetles dies.  Meanwhile, the grubs or larvae that started life early in spring begin to emerge as lawn foraging beetles. At this stage, it’s possible to have both adults and larvae feeding on your lawn and if the problem is ignored, dead lawn patches quickly appear.

Imidacloprid is new aged technology designed to kill soft bodied and sap sucking insects at a very low concentration.  When it is mixed and ready to spray, it has a very low toxicity to humans and animals. However, being systemic, it is absorbed by the roots of lawn grasses and while it kills all root eating lawn grubs, it has no effect on other beneficial insects in the soil. Imidacloprid remains active in the soil for up to three months.  This is a major breakthrough as an infestation of either lawn beetles or lawn grubs (or both) can occur over an extended period.

Quick guide to lawn beetle attack

A preventative spray with imidacloprid is warranted if

  • You experienced serious damage (bare patches, loose turf (easy to pull)) from either lawn beetles or lawn grubs last season.
  • You observed or observe large numbers of black beetles in your lawn this spring.
  • Large numbers of birds continue to land on your lawn and appear to be feeding (on lawn grubs).
  • You find very large numbers of witchetty grub-like larvae in garden beds adjacent to your lawn (five to six grubs per spadeful).

When to spray

  • The best time to spray your lawn for beetles and beetle larvae is October and March.

What to use

  • The best product on the market for home gardeners is Yates Complete. It contains 2 active ingredients - one being the imidacloprid I have already mentioned for the control of the larvae, and the other is called Cyfluthrin which will conrol the adult beetles.

Is it really lawn beetles?

Bare patches caused by lawn beetles and their larvae are easily confused with a range of management issues including

  • Compacted soil
  • Poor (uneven) watering
  • Annual weeds with a spreading canopy coming to the end of their growth cycle
  • Lawn diseases.

Experienced gardeners are quick to point out your best defence against black beetles is a well managed vigorous lawn. A healthy lawn can tolerate low populations of lawn beetles and their larvae

Comments (9)

Black beetle in deep and hibiscus being eaten

By: on 8 April 2018
Hi..i have a small house on one acre. I had 16 black beetle larvae alone in one small trough. They r everywhere, even in hanging baskets. How they can climb up 2M is beyond me. Just emptied out 5 baskets and each one had around 8 hige white grubs. How can the Yates Complete possibly get deep enough to kill the beetles or larvae. My Hibiscus leaves r constantly eaten and the flowers r beautiful but the leaves r covered in tiny holes. How often do u need to spray? What is the best product to use pls as the previous one wasn't effective. Is it a minute grub?

Joe stirling perth 18 march 2018 bloody black beet

By: on 18 March 2018
been using richgro spary on lawn beetle with no luck for some time lots of beetle come up lawn is looking sad used complete same resoult ready to dig lawn out need some help

Paul Munns Instant Lawn Response
Hi Joe, If your lawn is look so bad that you are ready to dig it up, then I would be highly possible that the issues facing your lawn are more than just Black Beetle Larvae. To eliminate beetle problems, I would recommend spraying with a chemical product containing an active ingredient called Imidacloprid (such as Yates Complete or Brunnings lawn grub and beetle kill). If you have already done that in the last 3 months and your lawn is not improving then beetles are not your problem. The best way to solve a problem like yours is to dig out a core sample and take it into a lawn specialist near you. They should be able to help you get it back on track. If you don't get an understanding of the issue, then there is a fair chance the same issues will return on any new lawn that you plant.

Curl Grub in garden beds and mulched areas

By: on 16 March 2018
Hi Paul, I have sprayed all my lawned areas with Yates Complete (early March '18) but I also have a huge infestation of curl grub in a large area that has been mulched with the free mulch from the local council. This area has three evergreen ash planted in it but nothing else. I also have the grubs in in my garden beds (no veg, just shrubs and ornamentals). Can I also spray the mulched areas and/or the garden beds with the Yates Complete? I've lost about 50 Madeira daisies very suddenly that were previously doing very well and 3 Arithropodiums - I can only assume that the grubs were responsible and am worried that more of my plants will succumb to this fate. Your advice would be much appreciated.

Paul Munns Instant Lawn Response
Hi The label on Yates Complete is very specific to Lawns and therefore I cant give you advice on what plants you can apply it to that are outside the scope of the label. What I can say is that active ingredients in Yates complete are Cyfluthrin and Imidacloprid which can be used on ornamental plants to control curl grub. Infestations of curl grub can definitely effect ornamental plants. Large (more mature) grubs are hard to control by any means so it may be the case that the current grubs in your garden mature into beetles and fly away. The best time to spray is going to be September/October right after the beetle eggs hatch so I would advise an application of Imidacloprid at that time. Because it sounds like you have a significant issue, I'd suggest a follow up spray in March 2019. Be careful to read the label though as there are some precautions to using this chemical. If you have a look on our site, we sell a product called Turf Culture Tirem which is a Imidicaloprid based insecticide. It covers a large area (around 4000m2 I think) so it works out to be a very economical way of controlling curl grub.

Lawn bettles

By: on 27 February 2018
I have an infestation of lawn bettles. I have treated lawn twice with richgo lawn an bettle killer. Am i better changing products??? We can i get the above yates product?? Bunnings or is there a commercial product i can get applied. I am from perth and live on the coast

Paul Munns Instant Lawn Response
Hi Michael. You need to use a beetle killer with an active called Imidacloprid such as Yates Complete. You can't get it from Bunnings but most smaller Mitre 10 stores sell it. If you have no luck there, you can get it from our webstore

Timing for black beetle eradication

By: on 21 February 2018
It is now late summer and both front and back lawns have been almost decimated by black beetle despite sevetal applications of various products. What can I do at this time of year to eradicate them and give my lawns a chance to regenerate.

Paul Munns Instant Lawn Response

It is possible that your issues are not Beetles. With the limited amount of information I have about your circumstances, I suspect that there could be other issues at play.

As far as rulling beetles out as the cause of your problems, there are a couple of reasons that beetle killers won't work properly. 1) timing: It is important to time your applications. The best times are November and March.  If you miss these windows, the larvae can grow too big and become resistant to chemical controls. 2) The product you use. Most products target the adult beetle, not the larvae. Its the larvae eating the roots of your lawn rather than the adult so its important to apply a product that contains an active ingredient called imidacloprid such as Yates Complete or Brunnings Lawn Grub and beetle kill. If you've applied one of these chemicals at the right time, then your problem isn't beetles as these products are extremely effective and last in the soil for 3 months. 


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