What Are Billbugs?
Billbugs are destructive turf pests found in several parts of Australia, including Queensland, New South Wales, Victoria, South Australia and Western Australia.
The Australian billbug, Sphenophorus brunnipennis, is also known as the La Plata weevil. Adult billbugs have hard brown bodies and a distinctive snout. Their larvae have cream-coloured bodies, orange-brown heads and no legs.
Adult females deposit eggs inside grass stems. After hatching, young larvae feed within the stems. As they grow, they move towards the crown and root zone, where their feeding causes more serious damage.
Because much of this activity occurs inside the plant or below the lawn surface, an infestation often develops before the homeowner notices visible symptoms.
Fox Mowing professionals inspect the grass, thatch, crowns and root zone to determine whether billbugs are responsible for the damage.
How Billbugs Damage Australian Lawns
Billbug larvae cause the greatest damage by feeding on the internal tissue of grass stems. This interrupts the movement of water and nutrients through the plant.
As the larvae develop, they leave the stems and begin feeding around the crown and roots. The grass gradually loses strength, changes from green to yellow and eventually turns brown.
Damage often starts as small, irregular patches. Without effective control, these patches spread and join together, leaving larger sections of dead or severely weakened turf.
Affected grass often breaks away easily when pulled because the larvae have damaged the connection between the grass, crown and root system. Fine material resembling sawdust might also appear around damaged stems.
Australian lawn problems such as heat stress, poor irrigation, fungal disease and other lawn pests often produce similar symptoms. A professional inspection helps identify the real cause before treatment begins.
Signs of a Billbug Infestation
Billbug damage often looks like a lawn suffering from dry weather or insufficient watering. Increasing irrigation alone will not resolve the problem when larvae are actively damaging the grass.
Common warning signs include:
- Irregular yellow or brown patches
- Grass stems which break away easily
- Hollowed or weakened stems
- Loose turf around damaged areas
- Cream-coloured, legless larvae beneath the thatch
- Fine, sawdust-like material around affected stems
- Lawn deterioration despite regular watering