Frogeye leaf spot, caused by the fungus Cercospora capsici, has distinctive symptoms on leaves, stems and peduncles of pepper and eggplant. Lesions are circular or oblong, tan in the center and surrounded with a necrotic border and often yellowing tissues. As the lesions expand, concentric rings may be present. The lesions resemble a frog’s eye, hence the name.
Several farms in Northwest Ohio have recently reported this disease in peppers. It has not been common in this area, and likely appeared due to the unusually hot weather this growing season. Frogeye leaf spot is favored by warm, wet conditions. Cercospora produces spores in the lesions that are dispersed by air, rain, overhead irrigation and tools and equipment.
This disease is managed by a combination of cultural practices and fungicide applications. Cercospora survives at least a year on crop residue, so residues should be plowed under to hasten decomposition. Drip irrigation should be used if possible. Fungicides typically recommended are Quadris, Quadris Top, Aprovia Top, Cabrio and mancozeb. Fungicide applications should be alternated according to fungicide mode of action (FRAC code) to reduce the development of fungicide resistance.