Biological Control of Pythium Seed Rot and Preemergence Damping-Off of Cotton with Enterobacter cloacae and Erwinia herbicola Applied as Seed Treatments. Eric B. Nelson, Assistant Professor, Department of Plant Pathology, University of Arkansas, Fayetteville 72701. . Plant Dis. 72:140-142. Accepted for publication 14 August 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0140.

Thirteen strains of Enterobacter cloacae and Erwinia herbicola were evaluated as biological seed treatments on cotton (Acala SJ-2). All strains reduced the incidence of Pythium seed rot and preemergence damping-off in naturally infested soil. Although three of four strains were as effective as metalaxyl when tested at 25 C, all strains of both bacteria were less effective at 15 C. At 35 C, little disease development was observed in any treatment. Bacterial strains suppressed colonization of germinating seeds by Pythium spp. at 15, 25, and 35 C. Control of Pythium seed rot and preemergence damping-off by E. cloacae and E. herbicola strains was correlated with suppression of seed colonization by Pythium spp. during the first 24 hr of seed germination.