Microdochium patch, also known as fusarium patch and pink snow mold occurs from late fall through spring. Although many USA turf managers know this disease as pink snow mold when it occurs under a snow cover, in Europe it is commonly known as Fusarium patch and the official name is Microdochium patch (pathogen: Microdochium nivale . Microdochium patch is especially active on Poa annua in areas that are shaded, wet, or north facing.
Creeping bentgrass is also susceptible, as is Poa pratensis and Lolium perenne to Microdochium patch but not to the same extent as Poa annua . Young, juvenile, or lush turf going into winter is more susceptible than mature stands.
Symptoms initially appear as a yellowing of the infected turf area that progresses rapidly to a rusty, reddish, brown color. The disease progresses producing circular patches that tend to be tan or whitish and in some cases have a pinkish border. These patches can range in size from several centimeters to ½ meter in diameter; with patches eventually coalescing into large blighted areas.
The disease is active under cool wet conditions when temperatures range from 0 and 15 C. Given this range, the disease can occur from late fall through mid-spring. In late winter or early spring when abundant moisture is present, the pathogen spores can be spread along drainage patterns, and easily moved by mowers producing a streaking pattern. Culturally, continue mowing until topgrowth ceases in the fall. This is especially important with Poa pratensis and Lolium perenne turf. Long matted turf tends to be more severely affected with this disease. In the spring disturbing infected sites through raking or mowing will limit disease activity. Although snow cover is not a prerequisite for disease development, installation of snow fences to limit snow drifting on greens and tees where snow fall occurs, will help reduce the disease severity.