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Disease Control and Pest Management

Control of Fusarium Crown and Root Rot of Greenhouse Tomatoes by Inhibiting Recolonization of Steam-Disinfested Soil with a Captafol Drench. Randall C. Rowe, Assistant Professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center, and The Ohio State University, Wooster, OH 44691; James D. Farley, Associate Professor, Department of Plant Pathology, Ohio Agricultural Research and Development Center, and The Ohio State University, Wooster, OH 44691. Phytopathology 68:1221-1224. Accepted for publication 27 February 1978. Copyright © 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-1221.

Of six fungicides applied to freshly steamed soil, captafol was most effective in inhibiting recolonization by Fusarium oxysporum. Soil drenches of captafol at concentrations as low as 200 μg/ml active ingredient kept the soil pathogen-free for 3 wk. The fungicide remained efficaceous when applied to soil as hot as 90 C but it was inactiviated by autoclaving. Captafol was completely inhibitory to mycelial growth and chlamydospore and microconidial germination of F. oxysporum in vitro at concentrations of 25, 2.5, and 0.5 μg/ml, respectively. Field tests in commercial tomato greenhouses demonstrated that application of captafol to freshly steamed soil provided economic control of Fusarium crown and root rot.