Terminal branch dieback along Commissary Ridge in the Bridger-Teton National Forest: Investigating white pine blister rust canker ages and rates of expansion

Abstract

White pine blister rust (WPBR) is caused by the non- native fungus, Cronartium ribicola, a devastating pathogen of North American five-needle pines. Over the past century and a quarter, this pathogen has proven to be one of the most damaging agents of five-needle white pines (Geils et al. 2010; Schoettle et al. 2022) and is the primary factor in the recent ESA listing of whitebark pine (Pinus albicaulis, WBP) as threatened in the USA. Whitebark pine is a high-elevation species of western mountain ecosystems that is highly susceptible to WPBR. Since its detection in the Rocky Mountains of Idaho, Montana, and Wyoming around 1926 (McDonald and Hoff, 2001), WPBR has reduced populations of WBP by as much as 70% in some areas including Glacier National Park (Kovalenko pers. comm.). In other areas to the south, WPBR continues to spread and intensify in WBP. White pine blister rust has not yet been detected in several more isolated WBP populations such as some in the Great Basin and has only recently been confirmed on WBP in the southern Sierra (Dudney et al. 2020).

Citation

Burns, Kelly; Hooten, Erin; Kearns, Holly; Newcomb, Maria; Schoettle, Anna; Shanahan, Erin. 2023. Terminal branch dieback along Commissary Ridge in the Bridger-Teton National Forest: Investigating white pine blister rust canker ages and rates of expansion. Nutcracker Notes. 44: 16-19.