Home Publications Seed and Seedling Diseases in the Western US Diseases of Container-Grown Conifer and Brush Seedlings USDA Forest Service Lucky Peak Nursery Boise, Idaho

Diseases of Container-Grown Conifer and Brush Seedlings USDA Forest Service Lucky Peak Nursery Boise, Idaho

Potentially-pathogenic fungi associated with diseases of container-grown Douglas-fir, Engelmann spruce, ponderosa pine, sagebrush, and bitterbrush seedlings at the USDA Forest Service Lucky Peak Nursery were identified. Several species of Fusarium, particularly F. proliferatum, extensively colonized roots of all diseased seedlings except bitterbrush. Foliage of diseased bitterbrush seedlings was commonly colonized with Botrytis cinerea. Needle and top dieback was a common symptom of root diseased conifer seedlings. Root diseased sagebrush seedlings were commonly grouped within containers where extensive mortality occurred. Root diseases and Botrytis are best prevented by using disease-free seed, containers, and growing media. Organic matter harboring pathogen inoculum should be removed from greenhouses between crops. Periodic removal of seedlings with disease symptoms is important to reduce secondary pathogen spread. Chemical pesticides are more effective for controlling Botrytis than for root diseases caused by Fusarium spp. Pesticide usage should be regulated to ensure that pathogens do not develop resistance to chemicals.


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Author(s): USDA Forest Service

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