Crown Gall of Peaches from Maryland, South Carolina, and Tennessee and Problems with Biological Control. R. Alconero, Research Plant Pathologist, Agricultural Research, SEA, U.S. Department of Agriculture, Northeast Regional Plant Introduction Station, Geneva, NY 14456. Plant Dis. 64:835-838. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1980. DOI: 10.1094/PD-64-835.

A high proportion of tumor-inducing Agrobacterium isolates from South Carolina (36%) and Tennessee (24%) were resistant to the K84 A. radiobacter antagonist commonly used in biological control. Pathogenic forms varied in sensitivity to K84. The weakly sensitive cultures needed a 3:1 or 10:1 ratio of K84 to pathogen for adequate control; these represented approximately 10% of the total pathogenic isolates found in the three states. Apparently latent infections by A. tumefaciens were found in nursery trees mailed from Maryland and Tennessee.

Keyword(s): sensitivity to agrocins.