Are Seed and Cone Pathogens Causing Significant Losses in Pacific Northwest Seed Orchards

摘要

Cones systematically collected in 1983 from eight Douglas-fir seed orchards in western Washington and Oregon yielded large numbers of common molds. Fungi isolated from apparently healthy, developing cones were similar to those from necrotic cones. Necrosis in cones aborted in early stages of development was apparently not associated with pathogenic fungi or bacteria. Necrotic areas in cones collected during the summer were associated with insect activity. Good crops of healthy cones were produced when fertilization and partial girdling had been used to stimulate cone production and insecticides used to control cone insects.