History of western white pine and blister rust in British Columbia

Abstract

Blister rust (Cronartium ribicola) entered Europe about 300 years after eastern white pine (Pinus strobus) was first planted in Europe. North America imported millions of infected seedlings after blister rust was firmly established throughout Europe. Blister rust probably entered into western North America on multiple occasions and spread throughout British Columbia (BC) by about 1930. Two large saw mills solely cutting western white pine (P. monticola) started in the 1920s with the main production for matches. Blister rust surveys in the 1940s painted a poor picture for the future of western white pine in BC, so it was discriminated against in forest management plans. Harvest volumes declined and the 2 mills ceased production about 1960. Selection of resistant clones from mature parents occurred between 1948 and 1960, but when it was evident that mature tree resistance was not likely to be in their seedlings the program was terminated. A program based on screening seedlings was started in 1983. The selected seedlings are hypothesized to possess age-related resistance that is being expressed at an early age. These and the better parents are incorporated into orchards. Key words: Cronartium, white pine, surveys, match blocks, rust resistance, PR proteins