Many stands of Pinus albicaulis across the species' entire natural range are infected with white pine blister rust (Cronartium ribicola), a fungal disease introduced from Europe. In the northern Rocky Mountains of the United States, whitebark pine mortality in some areas exceeds 90 percent, where the disease infests nearly . Cronartium ribicola occurs in whitebark pine to the northern limits of the species in the coastal ranges of British Columbia and the Canadian Rocky Mountains. The blister rust has also devastated the commercially valuable western white pine in these areas and made serious inroads in limber pine (Pinus flexilis) populations as well. Nearly 80 percent of whitebark pines in Mount Rainier National Park are infected with blister rust.