Spring Dead Spot Fungicides

Spring dead spot is a chronic root and crown disease of bermudagrass. Infection occurs before dormancy, but circular dead patches become obvious when healthy turf greens up in spring.

What to Look For

Sunken tan or straw-colored circles range from a few inches to several feet across. Dead stolons and roots pull easily, and weeds often invade the patches before bermudagrass grows back from the edges.

Why It Develops

Late-season nitrogen, excessive thatch, compaction, poor drainage, low mowing, and winter stress increase injury. Different Ophiosphaerella species respond differently to soil chemistry and nitrogen source.

Reduce Disease Pressure

• Avoid nitrogen within roughly six weeks of dormancy.
• Aerify and verticut during active summer growth to reduce thatch and compaction.
• Raise mowing height before dormancy where appropriate.
• Map patches and avoid root-inhibiting preemergence herbicides where recovery is needed.

What University Research and Extension Guidance Says

NC State found that fall potassium did not reduce disease and that nitrogen source response depends on the pathogen: calcium nitrate suppressed O. korrae, while ammonium sulfate suppressed O. herpotricha. University programs time preventive fungicides as soil temperatures fall toward 65–70°F and often water them into the crown and root zone.

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: NC State Extension: Spring Dead Spot in Turf; University of Kentucky: Chemical Control of Turfgrass Diseases 2024.