Billbugs in lawns
Billbug larvae start inside the stem and move down to the crowns and roots as they grow. Nematodes work on the larvae in the soil and on adults at the surface. Grewal rates S. carpocapsae and H. bacteriophora equally, Purdue prefers H. bacteriophora for larvae in the root zone, and Georgia calls nematode reliability questionable. Keep the soil moist for 10–14 days afterwards.
At a glance
- Damage
- Larvae hollow grass stems and chew crowns; turf dies in patches
- Type
- Root
- Settings
- Garden
- Threshold
- 1 or more larvae per cup-cutter core; Purdue notes 10 per ft² is common in healthy turf
- Release
- Heterorhabditis bacteriophora
- Rate
- About 1 billion per acre (≈250k /m², 23 million per 1,000 ft²), watered in straight away
How to confirm it
Do the tug test at the edge of a dead patch: pull a handful of stems. If they snap off at the soil line and the bases are hollow and packed with fine, sawdust-like frass, it is billbug. Dig 3 inches (7.5 cm) and look for small, legless, cream-white larvae with brown heads.
Identification, lifecycle, degree days and every control option are on the full Billbugs profile. Not sure it is this pest? Answer four questions about the damage.
Work it out
How many do I need?
Carries Heterorhabditis bacteriophora and lawn & turf through so nothing is re-entered. Open the calculator →