Abstract
Xanthomonas campestris pv. translucens strains isolated from diseased barley plants expressed ice nucleation activity at temperatures from -2 to -8 C. Strains from 12 other Xanthomonas species or X. campestris pathovars did not exhibit ice nucleation activity at temperatures above-8 C. The ice nucleation activity of six strains of X. c. pv. translucens varied both quantitatively and qualitatively. The -5 C ice nucleation activity of strains of X. c. pv. translucens was correlated significantly with extent of frost injury at -5 C to corn seedlings inoculated with these strains.