Hypoxylon Canker of Aspen

Paul, now with the WO staff.Hypoxylon canker, caused by the fungus Hypoxylon mammatum (Wahl.)Mill.(formerly H. pruinatum (Klot.)Cke.), is one of the most important killing diseases of aspen in eastern North America.In Michigan, Minnesota, and Wisconsin, the total impact of Hypoxylon canker has been estimated to be 30 percent of the annual net growth of aspen; in 1972, trees worth more than $4 million were lost to the disease. RangeThe disease is present throughout the range of aspen in North America, except Alaska.It occurs in the Eastern United States and adjacent Canada west into British Columbia and south through the Rocky Mountains into Arizona.The disease has also been found on European aspen in Russia, Czechoslovakia, and France.