Large patch
Rhizoctonia solani, large-patch group AG 2-2 LP.
Large patch affects warm-season turf during cool, wet periods when grass growth slows. Expanding yellow, tan or orange areas may remain visible through winter and into spring. Australian reports include confirmed cases on kikuyu, making grass type and seasonal timing important parts of identification.
Photo: Pete Dernoeden, Ph.D / Syngenta GreenCast · Full photo ↗
What to look for
- Broad, roughly circular patches or rings of yellow, tan or orange grass that expand or join.
- A brighter orange edge around an advancing patch, sometimes with a thinner or sunken centre.
- Damaged leaf bases with reddish-brown or dark lesions; affected leaves may detach unusually easily.
Check the grass and site
Relevant warm-season grasses include kikuyu, couch and zoysia. Symptoms vary between species and cultivars. The accompanying Syngenta field photograph specifically shows large patch in zoysia.
Confirm it before you treat it
Compare healthy and affected plants, including their leaf bases, and note whether patches appeared as growth slowed. Brown patch and other root or drainage problems can look similar. Seek a turf diagnosis when the affected area keeps expanding or returns each season.
What to do next
- Improve drainage and review irrigation so slow-growing turf is not left continually saturated.
- Reduce unnecessary wear on affected patches and address excessive thatch or compaction during a suitable recovery period.
- Review seasonal feeding with a turf adviser; avoid trying to force growth while the disease remains active.
Conditions matter more than dates.
Cool, wet weather around dormancy or spring recovery favours large patch. Shade, poor drainage and prolonged surface moisture can worsen damage. In Australia, affected warm-season turf may stay discoloured until warmer weather supports renewed growth.
Will the affected grass grow back?
Recovery depends on the surviving crowns and stems. Some turf improves as warm-season growth resumes; severely damaged areas may need repair after the cause and growing conditions have been addressed.
Compare similar problems
Brown patch
Expanding brown patches during warm, humid nights.
Identify & find a solution ↗
Waterlogging & drainage
Persistent wet feet can weaken turf and create recurring bare areas.
Identify & find a solution ↗Photo: Jonathan Clitheroe · CC BY-SA 2.0
Spring dead spot
Couch patches that fail to green up can reflect earlier root damage.
Identify & find a solution ↗Photo: Syngenta GreenCast
Reviewed 18 October 2026 · Turfmate. Identification guidance is not a laboratory diagnosis or a spray calendar.
Technical sources & image credits
- Large patch on zoysia, with orange-brown turf around the edges. Photo: Pete Dernoeden, Ph.D / Syngenta GreenCast · Syngenta content licence.
- Brown patch on tall fescue, with darker margins and fungal growth visible in damp conditions. Photo: Pete Dernoeden, Ph.D / Syngenta GreenCast · Syngenta content licence.
- Spring dead spot on a hybrid couch fairway. Photo: Syngenta GreenCast · Syngenta content licence.
Syngenta photographs are reproduced in full with attribution. Source grass species and settings are identified where supplied; photographs support identification and do not replace diagnosis.
- Envu Australia: Large Patch Technical Notes
- Envu Australia: Large Patch label update and local diagnosis
- Syngenta GreenCast: Large Patch
A Turfmate product link does not imply endorsement by a photographer or source.