Brown Ring Patch (Waitea Patch) Fungicides

Brown ring patch, also called Waitea patch, is caused by Waitea circinata and is most troublesome on closely mown annual bluegrass, creeping bentgrass, and rough bluegrass.

What to Look For

Yellow, tan, or bronze rings and irregular patches develop from a few inches to several feet across. Centers may remain green, and affected leaves, stems, and crowns can thin. The pattern can resemble yellow patch, summer patch, or nutrient stress.

Why It Develops

Humid, overcast weather in spring and fall, extended leaf wetness, low fertility, and stressed annual bluegrass favor disease. Night irrigation can extend the infection period.

Reduce Disease Pressure

• Water early enough for the canopy to dry before night.
• Use light, balanced nitrogen where appropriate instead of allowing severe deficiency.
• Improve airflow and drainage.
• Reduce annual bluegrass populations where practical.

What University Research and Extension Guidance Says

Kentucky reports that moderate nitrogen can improve recovery and fungicide performance. Two high-label-rate applications and mixtures of effective fungicides have sometimes outperformed a single application or single active ingredient. Penn State and Kentucky list effective options across several FRAC groups, but some labels state suppression rather than control.

Choosing and Using a Fungicide

Use the products below as a starting point, then match the active ingredient, FRAC group, turf species, use site, timing, rate, interval, and watering directions to the current product label. Preventive or very early applications are usually more reliable than rescue treatments after extensive injury. Rotate effective FRAC groups and combine fungicides with the cultural changes above.

Research and label note: University research may identify useful activity even when a current product label does not name this disease. That is research evidence, not a label direction. Apply a product only where the turf or application site and use pattern are permitted, and follow the complete label and applicable state requirements.

University sources: Penn State Extension: Brown Ring Patch; University of Kentucky: Chemical Control of Turfgrass Diseases 2024.