How to treat & prevent lawn grub infestation

If you find your lawn afflicted with the curse of the lawn grubs don’t despair. Treating and eradicating these pests is relatively easy. You will need to be particularly vigilant as the weather warms up, usually September to March, and after heavy rain. Couch and Kikuyu varieties are usually the most prone to attack and Buffalo to a lesser extent. Once you have determined that you are indeed under attack you must defend your lawn without delay.


As a result of extensive root damage caused by these larvae or lawn grubs, your lawn can no longer take up the moisture and nutrient it requires efficiently. This causes the grass to become dry and straw like, as it would during severe drought conditions.

When at its worst, the grass will actually be able to be peeled back easily from the soil surface as the roots have been eaten away. This is when you will inevitably find a large number of feeding larvae.

Common signs of a lawn grub infestation


Increased bird activity on your lawn is a good indication you have a lovely snack lurking beneath.

Brown Patches

Unusual brown patches in your lawn that spread quickly are likely due to root-feeding grubs.

Spongey lawn

A spongey lawn or one that lifts easily is a likely sign of grubs as they eat at your lawns root system.

A test for bugs!

A quick test you can do to confirm you have bugs in your lawn is to grab a bucket and fill it with warm soapy water. Pour this over different areas of your lawn and any bugs will rise to the surface within 10 minutes or so. Best carried out at dawn or dusk when the bugs are most active

How to treat bug infestation

Due to the rate at which lawn grubs feed (and move across your lawn), the amount of eggs they lay and the sheer numbers involved in an infestation delaying treatment can be disastrous. 

Luckily, there are lots of products on the market that can help treat your bug infestation and ones to help prevent future attacks too!


Because lawn grubs bury themselves in the soil during the day and come out to feed at night the most effective time to apply the treatment is as late in the day as possible while the adults are active.

If you are treating during a dry spell remember to water the insecticide into the lawn. If you are lucky enough to have rain coming then use the opportunity to your advantage; apply the treatment while the rain is falling. To ensure the grubs are eradicated, apply the treatment again in two weeks. This is especially important because eggs can take two to five weeks to hatch. A re-application at this point will ensure that any missed eggs or grubs are eliminated.


Unfortunately attack by these grubs can happen to any lawn and can occur numerous times during a season.

This is why we recommend Grub Guard Ultimate and Acelepryn GR, Acelepryn provides safe and effective control of black beetle while minimising the impact on the environment and non-target organisms, such as bees and earthworms.

Acelepryn targets pests such as black beetle, stem weevil, cut worm and army worm. The great thing about Acelepryn in comparison to other pesticides, is that it’s preventative. This is why spring is a great time to spread it out and protect your lawn for up to six months.

The most common bug we come across in South Australia is the Black Beetle, but it’s the grubs that are the most damaging.

Black beetle eggs are laid in spring and early summer. After several weeks the eggs hatch and the larvae or grubs emerge that then feed on the grass roots. It is when large numbers of these eggs hatch that it is a serious problem for some lawns. These larvae develop through 3 stages, the fully-grown larvae at the end of the third stage are around 25mm long. You will need to be particularly vigilant as the weather warms up, usually September to March, and after heavy rain.

If you can time your Acelepryn-powered product application to September and March, you should have year-round protection from bug infestations.

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