Early leaf spot caused by Cercospora arachidicola S. Hori (teleomorph Mycosphaerella arachidis Deighton) is one of two important leaf spot diseases in peanut (Arachis hypogaea L.) responsible for significant economic loss to the industry (1, 2). Infections by C. arachidicola appear as small necrotic lesions on the leaves, petioles, or stems, which may be followed by premature defoliation, and, if left unmanaged on susceptible cultivars, can severely decrease yield (1). An effective, yet expensive, disease management strategy consists of multiple fungicide applications throughout the growing season (3). Other strategies such as strip-tillage instead of conventional tillage (4) or weather forecast models that predict disease outbreaks (5) can help minimize the number of fungicide treatments. However, the development of leaf-spot-resistant cultivars that require no fungicide application would be the most desirable means of control (6)