Abstract
Twenty isolates of Ascochyta imperfecta were grown on a basic agar amended singly with 12 amino acids. The isolates changed differentially in color, marginal outline, aerial mycelium, and extent of radial growth. It is suggested that these responses are significant in the light of known differences in content of various amino acids in tissues of alfalfa, and changes which occur in this content under the influence of environment and artificial soil amendments.