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The information accessed from this screen is based on the publication: Hunt, R. S.; Unger, L. 1994. Tomentosus root disease. Forestry Canada, Forest Insect and Disease Survey, Forest Pest Leaflet No. 77 8p.
Tomentosus root disease is caused by the fungus Inonotus tomentosus, which is one of the most widespread root-rotting fungi in boreal and sub-boreal forests. It occurs throughout the temperate zone of the northern hemisphere. The root rot was first described in Canada in 1922, but due to its insidious habits, the extent and importance of the disease was largely overlooked until the 1960s. Unfortunately, I. circinatus, the causal agent of a root disease with identical symptoms, has not been recognized as distinct for many years, and the disease it causes is often thought to be caused by I. tomentosus. This has resulted in confusion about the hosts, distribution, and biology of tomentosus root disease. Only in the mid-1980s did the distribution and impact of this disease in British Columbia's forests become a major concern.
For more information, see the Tomentosus Root Disease Forest Pest Leaflet in the Canadian Forest Service bookstore.