الوصف:
Whitebark pine is an important reforestation
species in the northern Rocky Mountains for enhancement of wildlife habitat. Production of container-grown whitebark pine seedlings at the USDA Forest Service Nursery in Coeur d'Alene, Idaho has been increasing the past several years.
Diseases continue to be an important limiting
factor in seedling production. Recent
evaluations implicated Fusarium solani and F.
proliferatum as important pathogens of young
germinants and seedlings. Both fungal species
commonly contaminated whitebark pine seed
prior to sowing. Pathogen spread during stratification resulted in very high levels of seed contamination. Fusarium spp. adversely affected seed germination as well as initiated
high seedling disease levels. Not all seedlots
were equally affected by diseases, even though most seeds were contaminated. Seedling vigor,
probably related to seed germinative energy,
may have been an important factor affecting
disease severity. Efforts to reduce contamination
by mechanical brushing or treatments with
hydrogen peroxide or bleach solutions were
ineffective. Seed-borne inoculum is important in
disease epidemiology. Improved techniques to
reduce level of pathogen contamination and
spread during seed processing are required.