General Impact
Butternut, J. cinerea, is being killed throughout its native range in North America by the fungus S. clavigignenti-juglandacearum. The fungus may be threatening the viability of butternut as a species (Katovich and Ostry, 1998). It is second in value only to black walnut. Innes and Rainville (1996) state that, "Although the Sirococcus canker of butternut, caused by S. clavigignenti-juglandacearum, has caused damage only to butternut, J. cinerea, black walnut, J. nigra, and hybrids of walnut are also susceptible to a certain degree. In 1995, this disease was isolated for the first time from seedlings in two forest nurseries in Quebec. This constitutes the first report of the disease on butternut and black walnut seedlings in forest nurseries." Tisserat and Kuntz (1984) state that, "The incidence of butternut canker, incited by S. clavigignenti-juglandacearum, increased exponentially from 5% in 1978 to 76% in 1983 within an isolated butternut plantation." Anderson (1996) states that, "S. clavigignenti-juglandacearum kills trees of all ages. Branches and young saplings may be killed by a single canker, however, older trees are killed by multiple, coalescing cankers that either progressively kill the crown or eventually girdle the stem. Sprouts, if they develop, also become infected and are killed usually within the first few years. The nut husk can also become infected. USDA Forest Service Inventory and Analysis forest inventory data show a dramatic decrease in the number of live butternut trees in the United States. Live butternut decreased by 58 percent in Wisconsin and 84 percent in Michigan in the last 15 years. A recent Wisconsin Department of Natural Resources survey revealed that 91 percent of the live butternut throughout Wisconsin were diseased (Cummings and Carlson, 1993). Surveys in the southeast United States revealed that 77 percent of the butternut have been killed in North Carolina and Virginia, and infected trees continue to be found in new counties in most of the United States. (U.S.D.A. Forest Service, 1995 a and 1995 b.).
No Impact information recorded for Sirococcus clavigignenti-juglandacearum
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