Bugs can be a nuisance in your lawn!

Identify lawn bugs and pests and learn how to deal with them

There are a few different types of insect that become a 'pest' when they invade your lawn in large numbers. Some can do significant damage very quickly and therefore need to be treated as soon as you notice signs of their presence.

With this in mind, finding bugs and worms in your lawn isn’t always a sign that there is a problem, in fact it can mean that your lawn is thriving! Learning to identify the ‘problem’ bugs is the best way to ensure rapid and appropriate treatment without further damage to your lawn. Things like ants, spiders and worms, although annoying, are unlikely to damage your lawn. 

The one pest we come across most frequently in South Australia is the black beetle and its earlier, more damaging, larvae stage – more commonly known as ‘grubs’. Don’t worry, there is a great trick to identify grubs in your lawn and a few good treatment options too!

If you’re unsure, you can send us a photo of your damaged lawn and any bugs you find and we can help you identify them!

A quick test for bugs!

A great way to test for bugs in your lawn is with the ‘soapy water test’.

Simply mix some water with soap in a bucket and pour over the area you suspect is infested with bugs. Wait a few moments and any bugs in the ground will rise to the surface. This is a great opportunity to snap a quick picture and send it through to us so we can easily identify them for you.

Increased bird activity on your lawn can be a sign you have bugs!

Birds are wonderful guests to our homes and gardens. It’s actually a great sign you have done something right in your garden. While birds foraging on lawn is natural, they can become a pest when they begin digging and making a mess of the lawn.

The presence of birds on the lawn can be a sign there is a bug infestation, as birds will flock in numbers if there is enough bugs for them all to feed on. They can be our friend by removing bugs and weeds, but destructive behaviour begins when bugs are in abundance.

Types of lawn pests

What are root feeding grubs?

Root feeding grubs include; white curl grub, scarab beetle larvae, lawn beetle larvae or cockchafer. These are all common names for the juvenile stage of a lawn beetle that feeds on the lawn roots. These are not to be mixed up with the “witchetty grub”. These pests will feed on your lawns root system and will be a serious problem. Cool season varieties such as fescue and warm season varieties such as couch and kikuyu can experience major damage however they are usually not so much of an issue for buffalo varieties. Stressed and under nourished lawns are also at high risk of an infestation.

Adult beetles are black and shiny, about 15mm long with brown serrated legs. They lay their eggs in spring and early summer, they then develop into larvae that then feed on the roots. The pupal stage will cause no damage but in late spring/early summer when the grubs emerge, they will. The beetles are dormant or semi dormant in winter. A small infestation of black beetles can in some cases help your lawn, especially buffalo, where their tunnelling can act as an aeration technique but as soon as you see damage you should send them packing.

What are surface dwelling grubs?

‘Lawn Grub’ is a common name for surface dwelling caterpillars. Other names are sod webworm, army worm and cutworm that feed on the lawn leaves then become moths after their pupae stage. Each stage of the grubs life all cause similar issues on your otherwise healthy lawn. The moths are extremely fussy about where they lay their eggs, the healthiest lawn will be the spot for them. The caterpillars will then eat the best and leave the rest. To best understand how to control and prevent damage it is best to understand their life cycle.

If you begin to see brown or straw like patches through your lawn, or the leaves on your runners begin to disappear you could have an infestation of lawn grubs. Small green droppings will also become present which is basically your old lawn appearing. Caterpillars often feed at night so you often won’t see them. However you may see white/grey moths flying over your lawn or garden area, this could be an indication of a potential lawn grub problem. Lawn grubs are a seasonal issue and unfortunately they can affect your lawn multiple times throughout one season.

If you have had a minor infestation and the lawn is still in good condition the moths are likely to come back which will require a repeat treatment. You can follow up with fertilising to fast track recovery, make sure you fertilise in autumn to set your lawn up for winter and spring.

Common Lawn Pests

Black or African Lawn Beetle (Heteronychus arator)

Black Lawn Beetles are often blamed for damage to lawns but often is not the cause. As Black Beetles feed, they will continue to move throughout the soil, never staying in a single place too long. Lawn Beetles are active at the same time as the lawn is most active in it’s growing cycle. When the lawn goes dormant over Winter, so do the beetles and their grubs.

When To Treat Black Beetles? Black Lawn Beetles and their grub offspring feed regularly on the roots of lawns, and if ever found in concentrated very large quantities then this feeding can cause damage to the lawn and only then should treatment be considered. In theses cases – an inexpensive insecticide is applied to the soil and watered in, this will very effectively kill most lawn beetles in the soil, in a single application.

(Spodoptera mauritia)

BAD NEWS! Army worms are the caterpillar stage of a white/grey/brown moth, adult moth.

(Agrotis munda)

Similar to armyworms, cutworms feed and cut off the grass near the soil, hence the name, causing serious damage.

Sod Webworm
(Herpetogramma licapsisalis)

These greenish grey larvae/caterpillars have black spots along the body and are about 3cm long. The damage they cause is similar to armyworm and cutworm and they are often found operating at the same time.

How to get rid of lawn grubs, beetles and pests

To get rid of lawn grubs and other pests, an application of insecticide is necessary. Depending on the severity of the infestation, you may need more than one application. There are a few different products on the market, we recommend Acelepryn GR, Grub Guard or Amgrow Patrol.
Ensure you follow the product label and directions during application and that the product is safe to use on your lawn variety

Acelepryn GR

Granular insecticide that provides unmatched, season long grub and caterpillar control in a single application.

Grub Guard

A broad spectrum insecticide suitable for treatment of infestations of aphids, bugs, caterpillars and many other pests.

Amgrow Patrol

Fast acting, highly effective granular insecticide for the control of lawn beetles & grubs in the home garden.

2 ways to apply insecticide on your lawn

For surface dwelling grubs and pests

The best way to apply insecticide for surface dwelling pests is with an application in the late afternoon or early evening. Combine this with a light watering in to get the best result.

For root feeding grubs and pests

For root eating types, as they are further down in the soil, they will require a stronger concentrate of insecticide and a heavy watering in to ensure it gets right into the root of the lawn.

Less Common Lawn Pests

Wire worm & False Wire Worm

The Wire Worm and False Wire Worm is the larvae stage of the click-beetle and causes damage to underground roots and stems. They will also eat seed embryos preventing germination. An application of a high concentrate of insecticide will help to control them.

Two spotted mite
(Tetranychus Urticae)

Two spotted mites are very small mites that can affect some buffalos, couch and kikuyu in summer months leaving a webbing appearance on the lawn.

Couch grass mite
(Dolicotetranychus austraianus, Oligonychus eriophyes)

A couch grass mite is a minuscule mite that attacks couch in some areas. To control, spray with suitable pesticide or miticide.

Mole crickets
(Gryllotalpa brachyptera)

These common, but rarely seen, little insects tunnel through the soil eating the roots of your lawn. Buffalo grasses are not so much of a problem because of its dense growth.