VIEW ARTICLE

Etiology

A Root-Specific Decay of Grapevine Caused by Agrobacterium tumefaciens and A. radiobacter Biovar 3. T. J. Burr, Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456; A. L. Bishop(2), B. H. Katz(3), L. M. Blanchard(4), and C. Bazzi(5). (2)(3)(4)Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva 14456; (5)Institute of Plant Pathology, University of Bologna, Italy. Phytopathology 77:1424-1427. Accepted for publication 7 April 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-1424.

Tumorigenic (T) and nontumorigenic (NT) biovar 3 strains of Agrobacterium tumefaciens and A. radiobacter, respectively, were isolated from dark, sunken lesions on roots of grapevines grown in a commercial nursery. Roots of the grape cultivars Concord and Pinot Chardonnay decayed after inoculations with T and NT biovar 3 strains. Thirty-five strains of biovar 3 from several geographic areas worldwide reacted identically. Decay was restricted to the roots of grapes, whereas tumors were incited by T strains on grape shoots and on other hosts. No decay resulted when T and NT strains of biovars 1 and 2 were inoculated to grape roots. In addition, none of the strains decayed bean or sunflower roots. Root decay may provide sites for entrance of Agrobacterium into the grape vascular system and may cause detrimental effects on root development and vine growth.