The inheritance of resistance to two cercospora leaf-spots, Cercospora arachidicola (early leafspot) and Cercosporidium personatum (late leafspot) in Virginia-type peanuts (Arachis hypogaea L.), was determined using F₁ and F₂ generations and parental lines from a six parent diallel cross under natural field conditions. Two techniques for rating disease severity were employed. General combining ability, determined from both rating techniques, was significant for both F₁ and F₂ generations, indicating that resistance to both fungi and tolerance to infection i. e., minimal leaf defoliation, was primarily due to additive genetic effects.

The six parents produced offspring with different levels of resistance to both fungi. From the estimates of general combining ability effects, only NC-GP 343 and NC 5 produced progeny resistant to both early and late leaf-spot. NC 3033 was resistant to early leafspot, but susceptible to late leafspot. NC-Ac 3139, Florigiant and NC 2 were resistant to late leafspot, but susceptible to early leaf-spot. Disease indices ranked NC 3033 and NC-GP 343 as, overall, the most resistant of the six lines and the most useful to include in a cercospora leafspots resistance breeding program.