Effect and Characteristics of Pathogens on Foliage and Buds of Cold-Stored White Spruce and Lodgepole Pine Seedlings

Abstract

Molding of cold-stored, spring-lifted seedlings of Piceaglanca (Moench) Voss var. albertiana (S. Brown) Sarg. reached an index of 71.7 and of Pinuscontorta Dougl. var. latifolia Engelm. an index of 35.6 during 10 weeks of storage. Mortality and reduced growth after planting out were directly related to the degree of molding. Of 37 fungus species isolated from moldy seedlings, 10 were considered significant and were further studied. All 10 grew at 5 °C and eight of them grew at 0 °C. All 10 were able to infect moist foliage at 2 °C, but only Epicoccumpurpurascens Ehrenb. ex Schlecht. could infect dry foliage, and then only at 95% r.h. Storage at 0 °C reduced molding to less than one-half that at 25 °C. Suitable seedling storage methods are discussed.