Abstract
Large water-soaked and necrotic lesions were observed on leaves of Impatiens cultivar New Guinea Hybrid in a commercial greenhouse in Santa Barbara County, California. An oxidase-negative, fluorescent bacterium was consistently isolated from diseased tissues and identified as Pseudomonas syringae. Rapid water-soaking and necrotic symptoms resulted after New Guinea Hybrid and I. wallerana were inoculated with this bacterium. Hypersensitivity developed within 24 hr after inoculation of tobacco, tomato, common bean, and mung bean. No reactions occurred after inoculation of Begonia .times. semperflorens-cultorum, Dieffenbachia maculata, or Calendula officinalis. The bacterium was resistant to 1.6 mM CuSO4.