Brown Root Rot

Brown Root Rot (BRR) is a fungal disease that can cause plant injury that may be mistaken for winter injury.  The disease has been located in more dormant alfalfa growing regions where winter snow cover is more likely. This area includes Eastern, Western and Upper Midwest alfalfa production areas.   

Craig Grau, University of Wisconsin plant pathologist says: “ It’s primarily a problem in older stands. While most of our fungi are active during spring and summer, this one is asleep. When the plant goes into dormancy and temperatures drop, it starts activity. These fungi can grow below 32 degrees Fahrenheit.”

Grau further reports that: “producers with possible BRR problems should choose varieties with high winter survival scores, High Resistance to Phytophthora and other root diseases.

Dr. Jim Moutray, Director of Research at America’s Alfalfa, has studied the disease and notes, “Avalanche+Z is the only available commercial variety with some tolerance to BRR.” He also believes that many of America’s Alfalfa dormant varieties, including AmeriStand 403T will better tolerate the disease because they have superior winter survival scores, resistance to Phytophthora and other root diseases. America’s Alfalfa genetics have topped University of WI/MN winter survival trials for the last several years.

If you have unexplained winter injury, consider Avalanche+Z or AmeriStand 403T for better tolerance to BRR.