Control of Powdery Mildew on Greenhouse-grown Roses by Volatilization of Fungicides. D. L. Coyier, Research Plant Pathologist, Ornamental Plants Research Laboratory, ARS, USDA, Corvallis, OR 97330. J. J. Gallian, Graduate Student, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Plant Dis. 66:842-844. Accepted for publication 15 December 1981. 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, 1982. DOI: 10.1094/PD-66-842.

Rose powdery mildew was controlled in greenhouses by heating fungicides in shallow containers. Duration of heating and temperature requirements varied according to the physical and chemical properties of the fungicide. Treatments were applied at night to allow the greenhouse to be tightly sealed in order to maintain an effective dosage. Fenarimol and fenapanil effectively controlled rose powdery mildew and caused no phytotoxic effects. Volatilization of fungicides offers ease of application, uniform distribution, and reduced hazard to greenhouse personnel.

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