Sod webworm
Herpetogramma licarsisalis
Ragged leaf edges and small brown patches call for a caterpillar check.
Photo: Donald Hobern · CC BY 2.0. Resized from the original; no other edits.
What to look for
- Inspect fresh damage for a greenish to brown caterpillar with dark spots along the body; mature larvae can reach about 25 mm.
- Check chewed leaf edges and thin patches rather than relying on the colour of the whole lawn.
- Larvae shelter in thatch and debris during the day and feed after dark. Adult moths can fly low over turf around dusk.
Confirm it before you treat it
Photograph a caterpillar and the fresh patch edge, and record your grass variety. The two photographs here show adult moths from Queensland. A moth sighting helps you decide where to inspect; find larvae and recent feeding before attributing lawn decline to webworm.
What to do next
- Inspect an affected edge at dusk and compare it with nearby healthy turf. Include a size reference in insect photographs.
- Check that leaves are being eaten and compare with armyworm and cutworm. Root loss, persistent wetness or leaf lesions warrant a different investigation.
- Support recovery with mowing, water and nutrition suited to the grass and season. Record whether the damaged area is expanding before selecting treatment.
Where and when to check.
Australian turf sources describe adult emergence around late spring and early summer, with hatching and feeding continuing through summer. Late-season feeding can matter more when grass recovery slows.
Where your local season follows that pattern, use November–February as a monitoring prompt, and keep checking in March–April if chewing continues as growth slows. These are planning months inferred from the seasonal description, not measured outbreak dates. Warm northern or irrigated sites can differ; recent moth activity, larvae and feeding take priority. Record your location when asking for advice.
Do moths above the lawn mean I should treat it?
Inspect first. Many moths look similar, and the adult photographs do not establish a damaging larval population. A clear caterpillar photograph and fresh feeding evidence make the next step more reliable.
Adult identification, with a size reference.
Compare the adult wing markings in both views. Neither image shows a larva or damaged turf; photograph those separately at your site.
Photo: Donald Hobern · CC BY 2.0. Resized from the original; no other edits.
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Reviewed 11 October 2026 · Turfmate. Watch months are indicative planning prompts, not measured outbreak data or a spray calendar.
Technical sources & image credits
- Syngenta Australia: sod webworm biology and seasonal pattern
- Nuturf: sod webworm identification and recovery considerations
- Liquid Acelepryn: Australian label
- Adult sod webworm moth, Mission Beach, Queensland. The caterpillar stage feeds on turf; this photograph shows the adult.
Photo: Donald Hobern · CC BY 2.0. Resized from the original; no other edits. - A second adult moth view beside a ruler, Mission Beach, Queensland. Use it for adult identification, then inspect affected turf for larvae.
Photo: Donald Hobern · CC BY 2.0. Resized from the original; no other edits.
Product links do not imply endorsement by a photographer or source. Photos support identification; confirm the insect stage and current turf damage at your site.