Snow mold and winterkill avoidance

From Bill Kreuser at the University of Nebraska via TurfiNfo blog:

Many turf managers started thinking about pink snow mold (aka Microdochium patch) after the brief winter weather that blanketed parts of Nebraska last weekend. Snow mold diseases can be quite devastating around the Great Lakes and in the mountains where continuous winter snow cover frequently exceeds 90 days in length. For Nebraska, pink snow mold is typically superficial when it does occur. While the traditional name suggests that snow mold disease forms under snow, pink snow mold only needs cool temperatures and high moisture to cause the distinctive patches. Often times the patch will have a pink border and white mycelium.

Since snow isn’t required, pink snow mold can occur in the fall and continue into the spring. This time of year, it is common to find symptoms under tree leaves or in shaded areas. Golf course turfgrasses, especially new fall seedlings, are most susceptible to pink snow mold. Many fungicides are effective against snow mold in the central Great Plains. In high pressure areas, combinations of different fungicide classes are needed for complete control. Fungicide treatment for Nebraska lawns is typically not warranted. Frequent iron fertilizer applications have been shown to help control pink snow mold under the high disease pressure of Wisconsin and the Pacific Northwest. For more information about effective fungicides and iron fertilizer visit these resources:

University of Wisconsin Snow Mold Fungicide results

North Carolina State University TurfFacts

Oregon State BeaverTurf

Snow mold isn’t our biggest winter threat in Nebraska because our weather can be so variable. Those short warm and dry breaks for winter disrupt the disease cycle. When the dry weather is extended for weeks, winter desiccation becomes our main concern. Thatch management is central to desiccation prevention. Topdress and cultivate now to bury and protect the turfgrass crowns. Covers can help protect high value turf, but shouldn’t be applied until the ground is nearly frozen. During dry spells this winter, even small amounts of irrigation (less than 0.1”) can make the difference when then temperatures exceed 40F and the wind is blowing hard. The greatest risk for desiccation occurs in late winter.

Bill Kreuser, Assistant Professor, Extension Turfgrass Specialist, wkreuser2@unl.edu