After months of battling dollar spot, it’s easy to become desensitized to the appearance of small circular lesions of turf injury on putting greens and tees, especially when the maintenance focus transitions from providing peak-season conditions to leaf removal and other fall projects. Take the time to take a closer look because pink snow mold can cause significant turf injury when conditions for disease activity are ideal.
Pink snow mold is active over a wide range of temperatures – i.e., 30-60 degrees Fahrenheit – and the level of disease activity can ramp up rapidly after just a few consecutive cloudy days of cool, wet weather. It should come as no surprise that it has a knack for appearing first on heavily shaded greens and tees that hold dew for a long time. Furthermore, active disease will produce a heavy crop of spores that can be spread across the surface drainage pattern of a putting green during rain. Spores can also be spread from active lesions by mowing operations. Just imagine the bizarre pattern of disease streaks that can appear if a putting green infection was double cut in two directions.
Under certain environmental conditions, you could have active pink snow mold and dollar spot at the same time. Fortunately, it’s fairly easy to differentiate pink snow mold from dollar spot once you take a close look. There is usually a telltale bronze or pink cast to the irregular lesions on turf affected by pink snow mold and you won’t find the classic symptoms of small, white, discrete lesions associated with dollar spot.
Still not sure? Remove a sample of affected turf, place it in a plastic bag with a wet paper towel and pop it into the refrigerator overnight. Mycelial growth on turf the next morning indicates pink snow mold. A day or so of sunny, dry weather and warmer temperatures will check pink snow mold disease activity and there are plenty of contact and systemic fungicide options available to protect turf.
The first few bleak, chilly, wet days of fall are nice to spend in the shop with another cup of coffee while your body acclimates to the rude change in weather. On the other hand, the time spent scouting for disease activity on a raw, foggy day can help you avoid the pink snow mold blues.
Central Region Agronomists:
John Daniels, agronomist – jdaniels@usga.org
Zach Nicoludis, agronomist – znicoludis@usga.org
Information on the USGA’s Course Consulting Service