Resistance to Leaf Spot Caused by Cercosporidium personatum in Wild Arachis Species. P. Subrahmanyam, Plant Pathologist, Genetic Resources Unit, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru P.O., Andhra Pradesh 502 324, India. J. P. Moss, Principal Cytogeneticist, D. McDonald, Principal Plant Pathologist, P. V. Subba Rao, Research Associate, Groundnut Improvement Program, and V. R. Rao, Botanist, Genetic Resources Unit, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru P.O., Andhra Pradesh 502 324, India. Plant Dis. 69:951-954. Accepted for publication 25 March 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-951.

Ninety-six accessions of wild Arachis species were evaluated for reactions to the late leaf spot pathogen Cercosporidium personatum. Lesions were formed on leaflets of all accessions but were small and nonsporulating on all accessions of sections Erectoides, Triseminalae, Extranervosae, Rhizomatosae, and Caulorhizae. Species in section Arachis had lesions from 0.16 to 1 mm in diameter; 15 accessions had no sporulating lesions, and in the others, sporulation of lesions ranged from slight to extensive. Frequency of infection (number of lesions per square centimeter of leaf area) and percentage of defoliation varied greatly within each section and species.