Bentgrass Dead Spot Fungicides

Bentgrass dead spot is primarily a disease of young creeping bentgrass putting greens, especially sand-based greens during the first several years after establishment.

What to Look For

Small reddish-brown spots expand to straw-colored depressions, usually only a few inches across. Spots may be numerous and slow to recover, leaving a pitted putting surface.

Why It Develops

Warm weather, low mowing, drought or heat stress, low fertility, traffic, and immature root-zone microbial communities favor outbreaks. Symptoms are commonly most active in summer.

Reduce Disease Pressure

• Maintain adequate, balanced fertility and prevent wilt.
• Reduce mechanical stress and slightly raise mowing height during high-risk periods.
• Use cultivation and topdressing practices that support root growth without excessively injuring stressed turf.
• Encourage rapid recovery with sound establishment and traffic management.

What University Research and Extension Guidance Says

Kentucky's efficacy guide and Penn State's 2025 SDHI review identify boscalid as a particularly strong tool for bentgrass dead spot and list several effective combination products. University work also shows that the disease often declines as greens mature, but preventive programs are important on sites with a history of severe activity.

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: University of Kentucky: Chemical Control of Turfgrass Diseases 2024; Penn State Extension: SDHI Fungicides for Turfgrass Diseases.