Genetic selection in coastal Douglas-fir for tolerance to Swiss needle cast disease

Abstract

Swiss needle cast (SNC) of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), caused by the ascomycete fungus Phaeocryptopus gaeumannii, is associated with significant volume growth losses (20 to 50 percent) along the Oregon Coast. Although the pathogen is endemic, disease symptoms have intensified in coastal forests of Oregon and Washington since the early 1990s, reaching a peak of 177,691 symptomatic hectares detected in the 2011 aerial survey of western Oregon (fig. 1). This symptom expression is the highest in 16 years of survey, despite the conversion of tens of thousands of pure Douglas-fir plantations to mixed or alternate species over that period. Regular surveys have not been done in Washington State in the same way, but in 1999 and 2000, about 75,000 ha with visible symptoms were detected, and the disease continues to affect stands.

Parent Publication

• Proceedings of the fourth international workshop on the genetics of host-parasite interactions in forestry: Disease and insect resistance in forest trees

Citation

Jayawickrama, Keith J.S.; Shaw, David; Ye, Terrance Z. 2012. Genetic selection in coastal Douglas-fir for tolerance to Swiss needle cast disease. In: Sniezko, Richard A.; Yanchuk, Alvin D.; Kliejunas, John T.; Palmieri, Katharine M.; Alexander, Janice M.; Frankel, Susan J., tech. coords. Proceedings of the fourth international workshop on the genetics of host-parasite interactions in forestry: Disease and insect resistance in forest trees. Gen. Tech. Rep. PSW-GTR-240. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture. pp. 256-261.