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Analysis of Monocyclic Pathosystems with Erwinia-Lycopersicon as the Model. R. D. Berger, Professor, Department of Plant Pathology, University of Florida, Gainesville 32611; J. A. Bartz, associate professor, Department of Plant Pathology, University of Florida, Gainesville 32611. Phytopathology 72:365-369. Accepted for publication 14 May 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-365.

The progress of soft rot in tomatoes (Lycopersicon esculentum) following a single inoculation with Erwinia carotovora subsp. carotovora (Ecc) was typical of simple interest disease. The progress curves and curve segments were fit well by the monomolecular model. The curves were also fit to the Weibull model; >63% of the curves had values for the scale parameter near the idealized for simple interest disease (c = 1.0). Different inoculum concentrations, cultivar resistances, host maturities, storage temperatures, and predisposition affected length of latency, rate of disease development, and graphically asymptotic maximum disease. In nature, disease caused on tomato by Ecc may be of the polycyclic compound interest type, but in monocyclic experimentation the progress curves and responses to infection stimuli were like those of simple-interest-type plant diseases. Since the Ecc-tomato pathosystem is easy to handle and has rapid symptom expression, it could be a versatile, general model system to examine pathosystem interrelationships for simple interest diseases.