Billbugs / La Plata weevil
Sphenophorus brunnipennis
Hollow stems and legless larvae help separate billbug injury from other grubs.
Photo: Manaaki Whenua – Landcare Research · CC BY 4.0. Resized from the original; no other edits.
What to look for
- Cream-coloured larvae have an orange-brown head and no legs.
- Adults are dark weevils with a projecting snout.
- Damaged stems may be hollow with debris resembling sawdust.
Confirm it before you treat it
Pull apart affected tufts and inspect stems, crowns and nearby soil. Scarab grubs have legs; a brown patch alone does not identify the insect.
What to do next
- Photograph a larva with a size reference and record fresh damage.
- Inspect the boundary between affected and healthy turf.
- Discuss treatment while the target stage is confirmed; timing and placement depend on the exact label.
Where and when to look.
NSW and Queensland sites with Billbug history: Adults can be active from late August. Check through September–November, then inspect fresh stem and crown injury during summer. Hollow stems and loose tufts are useful prompts to look for larvae.
Other sites where the pest is confirmed: Follow local adult activity and turf growth rather than copying a NSW calendar. Australian egg-laying dates are not fully mapped, and larvae need to be identified before treatment.
Use these months for monitoring. For a prevention program, the Australian Liquid Acelepryn label uses first observations of overwintered adults in early spring as the timing trigger.
Is every curled white grub a billbug?
No. Check legs, head and feeding location, and obtain identification when unsure.
Another view of the same pest.
Compare the adult's snout, antennae and ridged wing covers. These adult views support identification; they do not show larvae or turf damage.
Photo: Manaaki Whenua – Landcare Research · CC BY 4.0. Image unchanged.
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Reviewed 11 October 2026 · Turfmate. Identification guidance is not a laboratory diagnosis or a spray calendar.
Technical sources & image credits
Syngenta Australia: Billbugs / La Plata weevil
Liquid Acelepryn: Australian label
Adult identification photographs by Manaaki Whenua – Landcare Research, supplied through Wikimedia Commons under CC BY 4.0. Product links do not imply endorsement by the photographer.