How to Control Argentine Stem Weevil in Australian Lawns

What are Argentine Stem Weevil? 

Appearance: The Argentine Stem Weevil is a lawn pest identifiable as a white, legless larvae or small, brownish-grey beetle with a large snout in adult form.

Damage: Adult weevils feed on the stems of grass plants, causing characteristic “notching” or “scalloping” on the edges of leaves.

“The real damage occurs during the larval stage,” Nathan says. “The larvae sits in the crown of the plant and eats from there, causing the affected areas to turn yellow and brown before dying.”

Season: This occurs most commonly in the warmer, summer months within Australia, so lawn owners should be on the lookout for the tell tale signs during their most active months, from November through to February.

How to Control Argentine Stem Weevils in Your Lawn  

Choose Resistant Grass Varieties: Bermuda and Couch grass varieties are known for their recovery following lawn pests such as the Argentine Stem Weevil.

Early detection: Regular inspections are crucial in pest management and prevention. Keep a close eye on your lawn for early signs of Argentine Stem Weevil infestation, such as notched leaves or browning patches. Birds pecking at your lawn is another sign that you might have weevils. Early detection allows for prompt action, minimising potential damage.

Lawn Maintenance: A well-maintained lawn is less susceptible to infestations. Regularly fertilise the lawn to promote strong, vigorous growth. Adequate watering and proper mowing practices can also contribute to a healthier lawn, making it less attractive to Argentine Stem Weevils.

Use an Insecticide 

Consider using insecticides as a targeted approach to control Argentine Stem Weevil populations. Insecticides containing bifenthrin or Acelepryn are commonly effective against these pests.

• Indigo Recruit 200SC 1L is a broad-spectrum selective insecticide that delivers superior results for the control of numerous beetles, including Garden Weevils.
• Indigo Rumbler 100SC 1L is a broad-spectrum insecticide for the control of larvae, ants and beetles, including Garden Weevils.
• Acelepryn 100ml or Acelepryn GR 4kg granular is a low environmental impact insecticide for the control of larvae and beetles, including Garden Weevils.

When to Use an Insecticide for Argentine Stem Weevil

It’s best to apply insecticide during the weevils’ active season, typically in late spring or early summer when you see the first sign of an Argentine Stem Weevil infection, characterised by wilting and yellowing leaves. 

Granular insecticides should be applied when adults are first seen during winter. Insecticides, like Acelepryn, has a low environmental impact and is suitable for Zoysia, Kikuyu, Couch and Buffalo grasses.

Shop now for Acelepryn on the myhomeTURF online shop.

Liquid pesticides should be sprayed when numbers peak, or when small larvae (less than 4mm) are found in the thatch or soil surface. Find liquid pesticides on the myhomeTURF online shop.

Quick Tip: Apply insecticides to your lawn in the late afternoon, as many insects feed at dusk and dawn.

How Long do Insecticides Take to Work? 

There should be a noticeable reduction in pest activity within 24 to 48 hours of insecticide application.

Some products will kill weevils at all three stages – larvae, young adults and adults – but it can take several repeat applications 10-14 days apart to break the life cycle and bring them under control.

Please ensure you always read the label and only use as directed by the manufacturer. 

How to Get Rid of Argentine Stem Weevils Naturally 

Proper Lawn Mowing: Mow regularly, but avoid cutting more than one-third of the grass height at a time. This helps maintain a dense turf, making it harder for the weevils to establish themselves.

Thatch Management: Thatch build up can create a favourable environment for Argentine Stem Weevil larvae. Regularly dethatch your lawn to reduce the organic matter layer, making it less hospitable for larvae to thrive.

How to Treat your Lawn After an Argentine Stem Weevil Infection 

Nathan stresses the importance of bringing your lawn back to health after a pest infection.

“Apply a wetting agent and use a fertiliser to invigorate your lawn,” Nathan says.

Wetting agent: LawnPride HydraMaxx 2L Hose-On 

Fertiliser:  LawnPride Kelp ER 2L Hose-On

Control Argentine Stem Weevils in Your Lawn with myhomeTURF

Controlling Argentine Stem Weevil in Australian lawns requires a proactive and multifaceted approach. By implementing preventive measures, cultural controls, and, when necessary, targeted chemical treatments, homeowners can protect their lawns from the damaging effects of these pests. Regular monitoring and early detection play crucial roles in maintaining a healthy lawn, ensuring that you can continue to enjoy lush, vibrant outdoor spaces for years to come.

All products mentioned in this article are available at myhomeTURF’s online shop and if you still have questions contact us for a tailored solution to your problem.