Genetic resistance to white pine blister rust is key but how it is managed will determine the future of high elevation five-needle pines

Abstract

The North American high elevation five-needle white pines define the forest-alpine ecotone in many mountain systems and provide watershed protection and wildlife habitat. Climate change is projected to be rapid and heightened in these same habitats, highlighting the importance of genetic diversity and adaptive capacity of the species that occupy them (Millar et al. 2007). The five-needle pines are also being challenged be an invasive fungal pathogen, Cronartium ribicola, that was introduced to North America in the early 1900s and causes the lethal disease white pine blister rust (WPBR) on five-needle white pines (subgenus Strobus). All the high elevation five-needle white pines of North America are susceptible to C. ribicola. The disease spread rapidly through host ranges in the moist forests of the northwest and east and continues to spread, though more slowly, into the drier habitats of the southern Rockies, Great Basin, and southwest. WPBR has killed many five-needle white pines in the north, though wasn’t detected in Colorado until the late 1990s and has yet to be found on trees in Utah or most of Great Basin (see map in Jacobi et al. 2018). As the pathogen continues to spread and the disease intensifies, the populations currently less affected may too follow the same trajectory as those to the north if effective management intervention is not pursued.

Citation

Schoettle, Anna W. 2020. Genetic resistance to white pine blister rust is key but how it is managed will determine the future of high elevation five-needle pines. In: Reynolds, Gregory J.; Wilhelmi, Nicholas P.; Palacios, Patsy, compilers. Proceeding of the 66th Western International Forest Disease Work Conference; 3-7 June 2019; Estes Park, CO. WIFDWC: www.wifdwc.org. p. 81-88.