Crown Gall of Pecan: A Survey of Agrobacterium Strains and Potential for Biological Control in Georgia. Hacène Bouzar, Graduate Student, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331. Larry W. Moore, Associate Professor, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331, and Norman W. Schaad, Associate Professor, Department of Plant Pathology, University of Georgia, Georgia Experiment Station, Experiment 30212. Plant Dis. 67:310-312. Accepted for publication 3 August 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-310.

Crown gall was found in numerous pecan orchards in Georgia. In some instances, 60% of the trees were diseased. Galled trees were less vigorous than uninfected trees and were often stunted. Among the pathogenic Agrobacterium strains isolated from 18 galled trees in six counties, biovar 1 strains predominated and most were sensitive to agrocin 84 in vitro. A representative biovar 1 strain from pecan was inhibited from infecting tomato seedlings by A. radiobacter strain K84. We would expect that biological control of crown gall in Georgia pecan orchards with the strain K84 would be successful. Additional antagonists for biocontrol of crown gall were isolated from potentially suppressive soil in a young peach orchard.