St. Paul, Minn. (March 4, 2002)—It’s the last thing golf course managers want to see, but after winter snows have receded it can be all too common. Dead grass. Usually caused by fungi, called snow molds. The molds not only turn golf courses from green to brown, but often are responsible for the destruction of other valued plants as well, including winter wheat and evergreen trees. Scientists have recently discovered however, that by pitting one fungus against another, in a kind of under-snow warfare, they may have found a way of controlling the disease.
There are more than a dozen species of snow molds, all of which thrive in the dark, humid conditions found under a thick layer of snow. The longer the snow cover lasts the better, which is why the disease is more prevalent in colder climates.
Its ability to survive in tough conditions has also made it a tough disease to combat. “Applying fungicides to kill snow mold is very costly and not very effective,” says Jenifer Huang McBeath, a plant health scientist at the University of Alaska Fairbanks’ Agricultural and Forestry Experiment Station. “Not only that, but the environments in which snow molds occur are often very fragile and highly sensitive to chemical use.”
In an attempt to find a more effective and environmentally friendly solution, McBeath has discovered that another fungus, isolated from the sub-arctic region of Alaska, may offer hope. The fungus appears to prey on the most common forms of snow mold, using them as a food source. What’s even better is that it does this without harming the plants upon which the snow molds are living. “This fungus is what we call a hyperparasite,” says McBeath. “It acts as a parasite on another parasite. And in this case ends up acting as a natural and very effective method of disease control as well.”
In one experiment McBeath and colleagues treated sections of the Fairbanks Golf and Country Club’s golf course, where they commonly lost up to half of their turf grass to snow mold every year. The results were better than they had imagined. “It was pretty remarkable,” says McBeath. “In the areas where we used the fungus there was no evidence of any snow mold, anywhere.” While research is still underway, McBeath remains optimistic. “I think we’re finally getting close to providing an effective tool for dealing with something that has been a problem for a long time.”
McBeath’s research on snow molds is the subject of the current APS feature story and can be found on APSnet at www.apsnet.org/publications/apsnetfeatures/Pages/SnowMold.aspx. The American Phytopathological Society (APS) is a professional scientific organization dedicated to the study and control of plant disease with 5,000 members worldwide.
