Lawn grubs may be small, but their impact on a lawn can be significant and swift. In Australia, lawn grub is a general term used to describe two common types of grubs: armyworms and white curl grubs.
Armyworms are grubs that grow into the moth Spodoptera Mauritia. The larvae are usually green, brown, or black, with stripes along their bodies. They feed on grass blades, causing significant lawn damage if left unchecked.
On the other hand, white curl grubs grow into various species of beetles, including the African black beetle and the Argentinian Scarab (often mistaken for Christmas beetles); they are characterised by their creamy white colour and C-shaped bodies. White curl grubs feed on grassroots and can cause similar damage to lawns as other types of lawn grubs.
Treating lawn grubs involves using insecticides like neem oil or specific grub control products like Acelepryn. Maintain lawn health by fertilising and watering profoundly and frequently. Consult a local horticulturist for the best products. Swift action is crucial with armyworms to prevent severe damage.
How do you know you have lawn grubs?
Common signs of worm grubs include:
- Brown patches: If you notice irregular brown patches in your lawn that don’t seem to recover with watering or fertilisation, it could be a sign of lawn grub infestation. These patches occur as the grubs feed on the grassroots, depriving the affected areas of nutrients and water.
- Spongy or wilting turf: Areas of the lawn infested with grubs may feel spongy underfoot or show signs of wilting despite adequate watering. This occurs as the grubs disrupt the root system, causing the grass to lose its ability to absorb water and nutrients effectively.
- Increased bird activity: Birds are natural predators of lawn grubs. Increased bird activity in your lawn could indicate grubs.
- Closely monitor lawn during late summer or early autumn: Lawn grubs are most active during the late summer and early autumn months. Keep an eye out for signs of lawn damage during this time, as it’s when grubs feed voraciously before entering the pupal stage.
The lawn grub test
- Cut a square foot of turf, inspecting the soil and thatch layer for grubs.
- Alternatively, pour soapy water on the affected area; if the grubs surface within ten minutes, it confirms the problem.
- Placing a towel on brown patches overnight can also reveal emergent grubs by morning.
How to treat lawn grubs
Step-by-step guide on how to get rid of lawn grub.
- Identify grub infestation: Look for signs such as irregular brown patches, spongy or wilting turf, and increased bird activity.
- Confirm grub presence: Dig small sections of affected turf to search for grubs beneath the surface. Or use the lawn grub test above.
- Choose treatment method: Select an appropriate treatment option, such as neem oil insecticide or Acelepryn grub control products.
- Read and follow instructions: Carefully read and follow the instructions on the selected product for proper application and safety precautions.
- Apply treatment: The chosen treatment is evenly across the affected lawn areas according to the recommended dosage.
- Water the lawn: Water the treated areas thoroughly to ensure the product penetrates the soil and reaches the grubs.
- Monitor and repeat if necessary: Monitor the lawn for signs of improvement and reapply the treatment if the infestation persists or worsens.
- Implement lawn care practices: Maintain lawn health by fertilising to replenish nutrients, particularly nitrogen, and watering deeply and frequently to aid recovery.
- Consult a professional: If the infestation persists despite treatment, seek advice from a local horticulturist or lawn care professional.
- Prevent future infestations: Implement preventive measures such as regular lawn maintenance, including dethatching and proper mowing height, to discourage future grub infestations.
While armyworms typically don’t kill lawns outright, their extensive feeding can cause severe damage, leading to patchy or dead areas if left untreated. If you act swiftly, you can restore the growth of your lawn and prevent further harm to your grass.
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