Lawn Caterpillar

About this pest

Physical Characteristics:

• Size: Typically 20-30mm long when fully grown.
• Colour: Green, brown, or black, often with stripes or patterns for camouflage.
• Body: Soft-bodied, cylindrical, with prominent hairs or spines on some species.
• Movement: Slow-moving caterpillars that primarily feed at night and hide in the soil during the day.

Common South African Names:

• Graswurms (Afrikaans) – Grass worms
• Lawn caterpillars
• Sod webworms

Why are Lawn Caterpillars Pests?

• They feed on grass blades and stems, leaving behind brown patches and damaging lawns.
• Outbreaks can quickly defoliate large areas of lawn, compromising its aesthetic appeal and health.
• Some species can also damage other plants like vegetables and ornamental flowers.

Combatting Lawn Caterpillars:

• Monitoring: Regularly check your lawn for signs of damage like brown patches, chewed blades, and caterpillar presence.
• Natural methods: Encourage natural predators like birds, wasps, and parasitic nematodes to control populations.
• Neem oil spray: A natural insecticide that disrupts caterpillar feeding and development.
• Insecticidal soap spray: Can kill caterpillars on contact, but reapplication might be needed.
• Chemical insecticides: Use registered insecticides as a last resort due to potential harm to beneficial insects and the environment.
• Cultural practices: Proper watering, mowing, and fertilization can create a healthy lawn less susceptible to pest problems.

Additional Tips:

• Early detection and intervention are crucial to prevent major damage from lawn caterpillars.
• Identify the specific caterpillar species present for targeted control measures.
• Consider the size and severity of the infestation when choosing a control method.
• Always follow the instructions on any insecticide products carefully.

By understanding the biology and behaviour of lawn caterpillars and implementing appropriate control measures, you can keep your South African lawn lush and green, free from these unwelcome guests.