Evaluation of Fungicides for Controlling Alternaria Diseases of Potato in Maine, 2024

Brown spot and early blight, caused by Alternaria alternata and A. solani, respectively, are two major foliar diseases of potato that frequently occur together in potato-growing regions. Both pathogens, members of the genus Alternaria, produce necrotic lesions on potato leaves, resulting in premature defoliation, reduced photosynthetic capacity, and significant yield losses under favorable environmental conditions. To address these threats, a field trial was conducted to evaluate fungicide programs for the management of potato Alternaria diseases. The results of this study provide practical guidance for managing Alternaria diseases through the rotation of fungicides with different modes of action.