Black-stain root disease on lodgepole pine in British Columbia

Abstract

Surveys were made for incidence and damage by black-stain root disease (Ceratocystiswageneri) on Pinuscontorta in British Columbia. Incidence surveys indicated the hard pine pathotype to be largely restricted to the west Kootenays, northern Okanagan, and southern Cariboo. Damage surveys of 177 ha in 12 stands revealed severe damage in pure, dense stands, 80 years and older, at elevations above 1000 m. In one-half of the stands, C. wageneri was associated with Armillariaobscura; in one-third, some trees in C. wageneri centres were currently infested with Dendroctonusponderosae. Most disease centres were small, but sometimes there were many per stand, so that up to 46% of a stand was affected. The pattern of disease centres suggested that unknown vectors were responsible for initiating disease centres. Isolations from excavated stumps indicated little survival of C. wageneri after 1 year and none after2 years. Infested stands can be clear-cut and regenerated to P. contorta without risk of infection from the previous stand.