How to identify and control lawn grubs

Written by Ian Thompson

Ian holds a Masters in Turf Management from Sydney University, has over 20 years experience working as a golf course Superintendent, turf manager, product formulation and development. We call him our resident Lawn genius.

As lawn lovers, there is nothing worse than seeing imperfection in your beautifully manicured lawn. Weeds are certainly annoying, but it’s lawn grubs that can do enough damage to bring your yard to its knees.

So, how to control lawn grubs in your lawn? Correct treatment begins by finding and identifying the lawn grubs that are doing the damage, thus allowing us to use the proper treatment.

How to Identify Signs of Lawn Grubs

It’s time to go scouting. After all, every good lawn is that way because we maintain a watchful eye over its condition.

In fact, there’s a good chance you’re here because you’ve already seen some of the tell-tale signs of insect damage.

The most common signs from African Black beetle larvae include:

  • Bird damage- as they strip out your lawn looking for their next meal
  • Yellow spotty patches, where the turf pulls straight out


The most common signs from Lawn Armyworm include:

  • Lawn that has been stripped of leaves
  • Brown patches that are widening fast


Where to Find Lawn Grubs  in Your Lawn

Now you know the signs, let’s see if we can find the lawn grub that’s doing damage to your lawn. The best place to start is at the edge of the damaged patch.

Look for signs and symptoms such as turf pulling straight out or those stripped leaves. Once you’ve looked for the signs of insect damage, the next step is to try and bring some lawn grubs to the surface. We do this by creating an irritating environment below the surface (in the thatch and soil) that the lawn grubs don’t enjoy, forcing them to come to the surface where we can find them.

The easiest way to do this is by applying dishwashing detergent to an area of suspected damage. Simply add 30ml of dishwashing detergent to a 9L watering can and apply over a 1m2 area (buckets work just as well). Give it a few minutes, and the lawn grub should come to the surface. This method works particularly well for lawn grubs like Lawn Armyworms, which are thatch dwellers.

Another fun way to identify pests is to go out looking at night, Lawn Armyworms are very active at night and are found crawling along the surface, and if you catch them in the act, you know what pest you have.

A commonly recommended identification technique is to trick the lawn grubs into believing they are hiding. Simply leave a damp towel out overnight, and lawn grubs like Lawn Armyworm will hide here thinking they are safe from the heat of the day, birds, but they won’t be safe from you.

These methods are a great place to start when looking for lawn grubs because they’re not destructive to the surface. Sadly, pests likeAfrican black beetle larvae, sometimes referred to as white grubs or curl grubs, are deeper dwelling, especially early in the season (September to December). This means they may not be found with the above methods.

So, if you still haven’t found your lawn grubs and you aren’t sure what pest you have, then a destructive method is a great way to find them. This simply involves digging up an area that has the damage with a spade and looking for the lawn grubs amongst the roots and soil.

Just a word of warning, we often see people claiming to have lawn grubs after birds are seen tearing up their lawn. While birds ripping at your lawn can be a sign of lawn grubs, they also love to eat fleshy rhizomes, particularly of Kikuyu, so only use the sight of birds as a reason to further inspect your lawn, not a reason to treat.

What Are Lawn Grubs?

Controlling lawn grubs always begins with correct identification. Correct identification allows the right product to be applied, which means the best results.

Hopefully, this article has helped you find the lawn grub attacking your lawn, and you are ready for treatment. If you haven’t been able to identify the lawn grub or were unable to locate any, then it’s time to contact the Lawn Genius with some photos or even check out our Pest Problem Solver.

Don’t let the names fool you; it’s time to stop calling them all lawn grubs and get a little more technical and break them apart, because that will help us understand them and their treatment methods.

As you have probably guessed, the most common “lawn grubs” that do substantial damage are Lawn Armyworm and African Black Beetle (in the larvae stage).

These guys are so common and destructive we felt they needed their own pages!

How to get rid of Armyworms

African Black Beetle

Lawn Armyworm

Lawn Armyworm (Spodoptera spp.) is not actually a worm. They are caterpillars. And just like the caterpillars that attack your veggie garden, they love to eat leaves. Being a pest that is above ground at night, they are much easier to kill, and it is very visual when you do.

The easiest way to kill these pests is to apply a product late at night while they are out feeding or about to feed. This way, the lawn grubs crawl through the insecticide almost straight after application.

This pest is very fast at creating damage, so we recommend something like Fortune Ultra, which knocks Lawn Armyworm down quickly.

The Lawn Armyworm is a formidable foe, and they create new generations very quickly. This means they will likely have laid eggs in your lawn (or a neighbour’s), and they will come back within a week or two. This will mean repeat sprays of Fortune Ultra (generally, 3-4 applications every two weeks). Alternatively, our preferred method is to apply Acelepryn as a one time, set-and-forget solution that lasts for 3-4 months against Lawn Armyworm. 

African Black Beetle

African Black Beetles are a little easier to control but you do need to get your timing right for best results. These beetles mate in Spring, and little baby grubs (larvae) appear about 5-6 weeks later. Unlike Lawn Armyworm, the African Black Beetle does not have multiple generations. However, they do have life cycle stages known as “instars”. The African Black Beetle larvae has three instars, and the amount of feeding on your lawn varies with each stage.

The first Instar is around September to November, depending on where you are in Australia. The larvae are tiny, so their eating is small, and any damage is likely to be masked by new Spring growth. Because of their size, they are also very susceptible to insecticide treatment at this stage. Treatment of this pest is recommended at this time of year for best results.

Unfortunately, African Black Beetle larvae grow up. By the third instar (January-March), they can be up to 3cm long, and their eating has sped up to match their growth. This is when the damage is clearly visible, and treatment is urgently required. For African Black beetle larvae, we recommend Acelepryn.

We recommend Acelepryn for control of African Black beetle larvae because, well, to put it simply, it is the gold standard in insect control for lawns.


The outstanding features of Acelepryn that we love include:

  • It controls a broad range of common lawn pests
  • It has a set-and-forget application which provides up to 6 months protection
  • It’s an easy to apply granular product
  • It has a fantastic environmental profile, safe for beneficial organisms like bees and earthworms
  • It has a fantastic safety profile; no PPE required, it is commonly used on schools and public parks
  • It paralyses African Black Beetle larvae in the soil where they can’t be eaten by birds
  • Strong binding with the soil means no movement into non-target areas
  • Resealable bag with four layers and vent allows for easy storage of any leftovers



Lawn grubs can quickly damage your lawn. By knowing how to identify the two most common types, and where they will be hiding, you can save your turf. Learn to identify African Black Beetles and Lawn Armyworms, or take a photo and ask The Lawn Genius today!

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