Early blight of tomato caused by Alternaria solani. The first observable symptoms are small, irregular, brownish to black lesions on the older, lower leaves.
Early blight on tomato fruit. The diseased areas often give a leathery appearance to the fruit. Severe damage can occur during all stages of fruit development.
Early blight on tomato leaf. The leaf tissue surrounding the lesions may become yellow, eventually resulting in the yellowing of the entire leaf.
Early blight on tomato stems. As the disease progresses it may create stem lesions similar in appearance of the leaves – brown with dark concentric rings and light centers. Image courtesy of Clemson University - USDA Cooperative Extension.