P&PDL Picture of the Week for
January 5, 2004

Snow Mold in Grass

Glenn Hardebeck, Turfgrass Research Agronomist, Department of Agronomy, Purdue University
Zac Reicher, Extension Turfgrass Specialist , Department of Agronomy, Purdue University

There are two types of snow mold that may affect turfgrass, gray snow mold and pink snow mold. Gray snow mold is rarely a serious problem in Indiana since it requires extended periods of snow cover to develop (30 days for mild infections to begin and 90 days or more for serious outbreaks). Unlike gray snow mold, pink snow mold does not require snow cover but snow cover can promote disease outbreaks in certain situations. Since pink snow mold is promoted by wet conditions, we can reduce the possibility of disease by maintaining normal mowing heights into the fall until growth has nearly stopped to avoid long grass that may become matted and wet. It is important not to take this idea to its extreme by scalping the lawn in late fall. Scalping will reduce the stored energy for next year. Another good control practice is to avoid piling snow on turf areas. In the spring the piled snow will keep the turf wet and matted under the pile while temps are perfect for disease development.

If you do see signs of pink snow mold in March or April as the winter snows melt away, don’t be too alarmed. In lawn situations, the areas will usually come back to life with time. You can hasten recovery by raking the matted turf and possibly reseeding the area if it does not improve after 3 or 4 mowings. More information on gray and pink snow mold can be found in BP-101-W and BP-102-W.


Click image to enlarge

Active pink snow mold on 1/2" bentgrass in early spring

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service