Lawn grubs are considered major lawn pests. They feed on grassroots, leaves, stems, and seed heads of grass, causing sections of grass in the lawn to die. The good news is that treatment and eradication of these pests is easy. Read on for information on how to get rid of lawn grubs and return your lawn to its former glory.
What are lawn grubs?
There are two major types of lawn grubs, the root-feeding White Curl Grub (sometimes confused with the Witchetty Grub) and the leaf-feeding (Armyworm) grub.
White Curl Grub (root-feeding grubs)
They are white, C-shaped larvae of the Cockchafer Beetle or the African black beetle. They live beneath the soil surface and feed on grassroots. These grubs can destroy entire lawns within a couple of weeks.
The White Curl Grub eventually turns into adult beetles and emerge from soil to mate and lay eggs that hatch into more grubs. The African Black Beetle lays eggs in spring and early summer. The eggs hatch after 2-5 weeks and the larvae emerge. Adult beetles rarely cause any harm. On the other hand, the larvae can cause severe damage to some lawns when in large numbers.
You need to be very vigilant as the weather warms up, usually from September through to March.
Signs that your lawn might have the White Curl Grub include:
- Dead patches: Irregular brownish to yellow patches on your lawn
- Spongy turf: grubs feed on grassroots, which leave patches feeling soft and spongy. The turf is not well anchored.
- Loose turf: Since the roots have been eaten away, it is common to see grass lying loosely on top of your lawn
- Increased bird and other wildlife activity: Grubs make tasty snacks for birds, moles, and other wildlife. The increased activity would be an indication of a grub infestation.
Leaf feeding grubs (Armyworms, Sod Webworm, and Cutworm)
The second type of lawn grubs is the larvae of moths. They consume the leaves, stems, and seed heads of grass. They can destroy entire lawns leaving behind practically nothing but bare earth.
Signs that your lawn has leaf feeding lawn grub include:
- It is easy to identify the type of lawn grubs as they are on the lawn’s surface at night when they feed.
- Patches of lawn suddenly dying.
- You may notice small grey moths flying around the lawn – adult armyworms (moths) looking for a place to lay eggs. They often lay eggs in little orange clusters under the eaves of houses.
Though they can be a menace, it is vital to acknowledge that some of these lawn grubs play an important role in the lawn’s ecosystem – in the right numbers, that is.
How to identify lawn grub infestation?
Before treating grubs in your lawns, it is crucial to confirm that it is grubs that are damaging your lawn. Many lawn issues, including drought stress, disease, weed damage, and more, resemble grub damage.
While you can see and identify leaf feeding grub, they live below the surface. Use any of these three methods to confirm the leaf feeding lawn grub infestation.
- The first method is to place a wet hessian bag, towel, or piece of carpet on your lawn overnight. Lift the bag in the morning to see if the grubs have come to the surface.
- The second method is to pour a bucket of soapy water over the edge of an affected area. If there are grubs there, they will come to the surface after about 10 minutes.
- Look for small red wasps that hunt the grubs as a place to lay their eggs.
To find root-feeding White Curl Grub is not as easy as they do not come to the surface.
- Use a shovel to dig up some turf that looks like it is under attack from the grubs on the edge of a damaged area.
How to get rid of lawn grub
Given the rate at which grub destroy lawns and the huge numbers involved in an infestation, delaying treatment can be disastrous. To get rid of both lawn grubs, the application of a suitable insecticide is suitable.
A preventative insecticide such as Acelepryn GR can get rid of grub quickly and efficiently while providing season-long grub control.
For leaf feeding lawn grub, Bifenthrin ( trade name Five Star) can be applied for quick action. Apply the insecticide late in the afternoon or early evenings. Combine this with light watering for the best results.
For the root-feeding lawn grubs, insecticides need to be watered through the lawn and thatch layer to make contact with them. A higher concentration of insecticides like Bifenthrin and a heavier water application is required to get to the target area.
To make sure you get rid of grub, apply the treatment again in 2 weeks. This time frame is crucial because the African Black Beetle eggs take 2-5 weeks to hatch. Reapplication eliminates any missed egg or grub.
Prevention of lawn grub
Lawn grubs are a seasonal issue and can affect your lawn several times a year. More so, during each summer and autumn season. You can follow up preventive treatment with fertiliser to fast track recovery. Use fertiliser in autumn to set up your lawn for winter and spring.
Your greatest weapon against grub is keeping your lawns healthy. Healthy laws can sustain more grubs without damage. Keep your lawns properly watered and mowed to help prevent grub damage. Golden Finch Lawns will provide you with extensive lawn care advice to ensure that your lawn is well taken care of to avoid the lawn grub menace.