The first round of snow and cold is gripping much of the country, signaling that winter is officially on the doorstep (or has barged in the front door). For many the last activity prior to closing the course for winter is installing the covers on the putting greens. The potential benefits (protection from various types of winter injury and earlier spring green-up) and drawbacks (significant cost to purchase/install and the potential for suffocation injury) of winter covers are fairly well established and I won’t rehash them here. Snow mold, however, is a potential drawback that isn’t often mentioned when discussing whether or not to use covers. Common sense seems to suggest that winter covers would trap heat and moisture near the surface, producing ideal conditions for snow mold development even when no snow is present. This is not a new concept, even mentioned by the legendary Dr. James Watson back in a 1960 edition of The Golf Course Reporter, ‘The environment produced under the covers is most conducive to disease development. Therefore, treatment to prevent disease, especially snowmold, is necessary.’ To investigate the impact of modern covers on snow mold severity we recently completed a 2-year study at Antigo Bass Lake Country Club in central Wisconsin with Evergreen® and Green Jacket® covers. The study is currently being written for publication, but in brief what we observed was that Evergreen® covers did not significantly increase the level of gray snow mold over the non-covered plots (both had approximately 45% disease in spring of 2012). Green Jacket® covers, however, had nearly double the amount of snow mold (80%) as both the Evergreen® and non-covered plots. The good news for Green Jacket® users, though, is that when an effective snow mold application (Interface + Triton Flo) was made prior to covering snow mold severity was less than 5% no matter what cover was used. These results suggest that winter covers, especially Green Jacket® covers, can increase the severity of snow mold but that effective fungicide applications made prior to covering will suppress snow mold even under optimal conditions for fungal growth. I want to briefly thank the Wisconsin Golf Course Superintendents Association, the Northern Great Lakes Golf Course Superintendents Association, and Antigo Bass Lake Superintendent Dave van Auken for supporting this research. A full and detailed report of this research should be available in the coming months.