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Home → Publications → National Nursery Proceedings → 1997 → Preliminary Evaluation of Fungicides for Control of Damping-Off Disease in Container Grown Red Pine Seedlings

Preliminary Evaluation of Fungicides for Control of Damping-Off Disease in Container Grown Red Pine Seedlings

Historically the fungicide benomyl has been widely used by greenhouse managers to control damping- off diseases in container grown conifer seedlings. In 1991, product labeling for benomyl underwent major changes and all greenhouse and ornamental uses were eliminated. Greenhouse managers, no longer able to use benomyl, were faced with the immediate need to identify effective alternative fungicides. This study was undertaken to investigate the effectiveness of several alternative fungicides in controlling damping-off diseases in red pine seedlings, grown under operational greenhouse conditions and naturally occurring disease pressure. The decision to design this study using operational greenhouse conditions and naturally occurring disease pressure was made in response to the immediate need to identify alternative fungicides and transfer this information quickly to greenhouse managers, and the lack of pathological information relating to disease development. Baseline data regarding the species of pathogenic fungi occurring on red pine, and specific disease inoculum levels that incite disease symptoms are unknown, and the determination of such data would have required many months of laboratory and greenhouse testing. Seedlings were grown using cultural practices consistent with common greenhouse operations including the reuse of surface disinfected styroblocks and the sowing of seed which received no surface washing or fungicide seed treatment. The seedlings were grown under conditions of naturally occurring disease pressure and were not artificially inoculated with pathogenic fungi. It was speculated that disease inoculum would be present in cracks and crevices of reused styroblocks and in/on seeds. Damping-off and root rot disease did develop, and disease pressure was sufficient to cause a significant reduction in seedling quality in the untreated control treatment when compared to the fungicide treatments.


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Author(s): Jill D. Pokorny, Jana K. Rykhus

Publication: National Nursery Proceedings - 1997

Event: The Northeastern Forest and Nursery Association Conference
1997 - Bemidji, MN