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Ecology and Epidemiology

Overwintering, Seed Disinfestation, and Pathogenicity Studies of the Tobacco Hollow Stalk Pathogen, Erwinia carotovora var. carotovora. John L. Mc Intyre, Associate and Assistant Plant Pathologist, Department of Plant Pathology and Botany, The Connecticut Agricultural Experiment Station, New Haven, CT 06504; David C. Sands(2), and G. S. Taylor(3). (2)Associate and Assistant Plant Pathologist, Department of Plant Pathology and Botany, The Connecticut Agricultural Experiment Station, New Haven, CT 06504, Present address: Department of Plant Pathology, Montana State University, Bozeman, MT 59715; (3)Plant Pathologist, Department of Plant Pathology and Botany, The Connecticut Agricultural Experiment Station, Windsor, CT 06095. Phytopathology 68:435-440. Accepted for publication 10 August 1977. Copyright 1978 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-68-435.

In Connecticut, the tobacco hollow stalk pathogen, Erwinia carotovora var. carotovora, could not be recovered from soil in the spring in tobacco fields where it had been detected in soil the previous fall. The bacterium was isolated in the spring from decaying tobacco root crowns which had been in the soil since the previous fall. The pathogen could be cultured from tobacco seed stored for 8 mo. A 12-min hot water treatment at 50 C eliminated the pathogen from naturally and artificially infested seeds without affecting seed germination. This bacterium caused hollow stalk symptoms when inoculated into tobacco plants in the greenhouse, but only a few isolates from other Erwinia spp. and nontobacco isolates of E. carotovora var. carotovora caused pith necrosis. Tobacco isolates of E. carotovora var. carotovora caused necrosis of inoculated tobacco tissue cultures sooner (24 hr) and at lower concentrations (10 bacteria per callus) than did other Erwinia strains. Tobacco isolates usually could be separated from nontobacco isolates of E. carotovora var. carotovora by a positive lipase test on an agar medium.