Armyworms are the larvae of various moth species, including the Common Armyworm (Mythimna convecta) and the Lawn Armyworm (Spodoptera mauritia). These pests are known for their destructive feeding habits, causing significant damage to lawns and crops across Australia.

Lifecycle in Australia

1. Egg Stage: Adult moths lay clusters of eggs on grass blades or other vegetation during late spring and summer. Each female can lay hundreds of eggs.

2. Larval Stage: Eggs hatch into larvae (armyworms) within a few days. The larvae go through several instars, growing larger with each stage. During this time, they feed voraciously on grass leaves, causing the most damage. This stage can last several weeks.

3. Pupal Stage: Mature larvae burrow into the soil to pupate. This stage lasts about two weeks.

4. Adult Stage: Adult moths emerge from the pupae, ready to mate and lay eggs, continuing the cycle. The adult moths are nocturnal and are often attracted to lights.

Why They Are a Problem for Lawns

• Rapid Feeding: Armyworms can consume large amounts of grass in a short period, creating irregular bare patches and thinning the lawn.

• High Mobility: The larvae can move in large groups (hence the name “armyworm”), quickly spreading across and damaging large areas of turf.

• Multiple Generations: In favorable conditions, several generations can occur within a single growing season, leading to repeated infestations.

Control Measures

• Monitoring: Regularly inspect your lawn for signs of armyworm activity, especially during late spring and summer.

• Insecticides: Apply appropriate insecticides when larvae are young and actively feeding for effective control. Acelepryn and Fortune Ultra are Great Options.

• Lawn Maintenance: Keep your lawn healthy with proper fertilisation, mowing, and watering to help it recover from damage and withstand infestations.