Bacterial Blister Bark and Blight of Fruit Spurs of Apple in South Africa Caused by Pseudomonas syringae pv. syringae. E. Lucienne Mansvelt, Fruit and Fruit Technology Research Institute, Private Bag X5013, Stellenbosch 7600, South Africa. M. J. Hattingh, Department of Plant Pathology, University of Stellenbosch, Stellenbosch 7600, South Africa. Plant Dis. 70:403-405. Accepted for publication 4 November 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/PD-70-403.

Green fluorescent, oxidase-negative bacteria were consistently isolated from margins of lesions on trunks, stems, and blossoms of diseased apple (Malus pumila) trees in South Africa. Strains were characterized by colony morphology on Pseudomonas syringae agar medium and by tests for gelatin liquefaction, aesculin hydrolysis, tyrosinase activity, and tartrate utilization. Pseudomonas syringae pv. syringae (P. s. pv. syringae) and intermediate forms predominated. Typical blister bark symptoms developed after inoculation of P. s. pv. syringae into apple trees.