Pine-pine gall rust on young jack pine in northwestern Ontario

Pine-pine gall rust, caused by Endocronartium harknessii accounted for >99% of all stem rusts encountered during a 1987 survey of Pinus banksiana in 71 plantations regenerated with planted stock or by seeding. Significant differences in rust incidence were detected among the six districts in the region within mean incidence ranging from 6.7-17.2%. Average level of mortality attributed to rust was low (3.4%). -from Authors