Effects of Host Resistance on Germination of Cercospora arachidicola on Peanut Leaf Surfaces

Conidial germination by a North Carolina field-isolate of Cercospora arachidicola Hori was studied on leaf surfaces of two highly resistant and two susceptible peanut (Arachis hypogaea L.) genotypes under 5 day/night temperature regimes. Conidia germinated at all temperature regimes, but a greater percentage germinated at the coolest temperature regimes of 26 C day/20 C night and constant 24 C than in warmer temperature regimes. Percentage germination differed significantly with respect to time and genotype in each temperature regime. Fewer conidia germinated on resistant compared to susceptible genotypes, with lowest germination on the resistant genotype 91 PA 150 (a Virginia type derived from a cross of A. hypogaea and A. cardenasii Krapov. and W. C. Gregory). Conidia germinated more quickly and more conidia germinated overall on the susceptible NC 7 than on the other genotypes tested