VIEW ARTICLE

Ecology and Epidemiology

Isolation of Agrobacterium tumefaciens Biovar 3 from Grapevine Galls and Sap, and from Vineyard Soil. T. J. Burr, Assistant professor, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456; B. H. Katz, research technician, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456. Phytopathology 73:163-165. Accepted for publication 16 July 1982. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-163.

Agrobacterium tumefaciens biovar 3 (AT 3) was isolated from grapevine galls, sap of “bleeding” vines, and from vineyard soil by using a selective medium. AT 3 was the predominant biovar isolated from galls. The bacterium was recovered from sap from seven of 24 infected vines and one of 17 apparently healthy vines. Ten sap isolates were identified as AT 3 and all were pathogenic on grapevine and sunflower. Two hundred forty-four typical colonies of Agrobacterium were selected from dilution plates from 30 vineyard soil samples. Five of these strains were pathogenic, three being AT 3 and two similar to A. tumefaciens biovar 1. Almost all of the AT 3 strains from galls, sap, and soil caused galls on tomato, sunflower, and grapevine inoculated in greenhouse tests.