Home Publications Seed and Seedling Diseases in the Western US Botrytis Blight of Container-Grown Western Redcedar Seedlings

Botrytis Blight of Container-Grown Western Redcedar Seedlings

Blight caused by Botrytis cinerea was identified on container-grown western red cedar seedlings at the USDA Forest Service Nursery in Coeur d'Alene, Idaho during 1993. Stock produced in 1992 and freezer-stored for spring planting in 1993 had high levels of B. cinerea infection. Some lots were more damaged than others. Most infection started on primary leaves produced along the main stem of seedlings. The fungus often invaded the stem from infected primary leaves, then produced cankers that enlarged around the circumference, causing girdling. Most stem-infected seedlings had a single noticeable infection. Secondary leaf infection was common, particularly in groups of seedlings packed together for storage. Botrytis cinerea was also recovered from roots of more than 50 percent of seedlings with foliar or stem infections. Botrytis detected on stock growing under shadehouses in the fall (October - November) was concentrated on lower foliage. Producing larger seedlings in styroblock 7 (metric = 323) containers may have contributed to damage by this pathogen. Western redcedar is very susceptible to B. cinerea and several cultural approaches will be required to reduce future damage.

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Author(s): USDA Forest Service

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