Biological Control of Fusarium Wilt of Greenhouse-Grown Chrysanthemums. J. C. Locke, Research Plant Pathologist, Florist and Nursery Crops Laboratory, Horticultural Science Institute, ARS, USDA, Beltsville, MD 20705. J. J. Marois and G. C. Papavizas, Research Plant Pathologists, Soilborne Diseases Laboratory, Plant Protection Institute, ARS, USDA, Beltsville, MD 20705. Plant Dis. 69:167-169. Accepted for publication 24 August 1984. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1985. DOI: 10.1094/PD-69-167.

Twenty-two isolates and biotypes of soil fungi representing three genera and five species were tested in the greenhouse against Fusarium oxysporum f. sp. chrysanthemi, causal agent of Fusarium wilt of chrysanthemum (Chrysanthemum morifolium). The four biocontrol agents that reduced disease incidence the most were tested alone and in several combinations in a greenhouse stock plant production system using the susceptible cultivar Yellow Delaware. A wild-type isolate of Trichoderma viride (T-1) and a benomyl-resistant biotype (T-1-R9), alone or in combination with Aspergillus ochraceus, reduced disease by at least 50% in vegetatively maintained plants. T-1-R9 was evaluated in a cut flower production system using the susceptible cultivar Cirbronze. Use of T-1-R9 with as few as two benomyl drenches provided control equal to a commercial integrated control procedure.

Keyword(s): biorational.