VIEW ARTICLE

Reaction of Cowpea Seedlings to Phytopathogenic Bacteria. Mingtan Lai, Plant Pathologist, Laboratory Services, Division of Plant Industry, California Department of Food and Agriculture, Sacramento 95814; Barbara Hass, Agricultural Biological Technician, Laboratory Services, Division of Plant Industry, California Department of Food and Agriculture, Sacramento 95814. Phytopathology 63:1099-1103. Accepted for publication 26 February 1973. DOI: 10.1094/Phyto-63-1099.

Inoculation of cowpea (Vigna sinensis) was one of several tests found valuable for rapid identification of isolates of Pseudomonas syringae. A total of 413 bacterial cultures were tested, which included 69 isolates of four Agrobacterium spp., 23 of seven Corynebacterium spp., 55 of 10 Erwinia spp., 214 of 35 Pseudomonas spp., and 52 of 12 Xanthomonas spp. Positive results consisted of formation of brown necrotic lesions on leaves 24 hr after inoculation, when inoculated plants were maintained in a moist chamber. The cowpea variety, ‘California Blackeye 3’, reacted to two isolates of A. tumefaciens, eight of E. amylovora, two of P. eriobotryae, one of P. cattleyae, and all tested isolates of P. alliicola, P. cichorii, P. pisi, P. syringae, and X. vesicatoria. When 10 cowpea varieties were inoculated with 45 isolates of P. syringae, only California Blackeye 3 gave a positive reaction for all isolates.