Early blight of potato is

Early blight of potatoes is Soil borne disease.
Early blight and late blight are terrible soil-borne diseases. Early blight also called Alternaria is a soil-borne fungal vector with the main two species being Alternaria solani and Alternaria alternata.
The disease affects leaves, stems and tubers and can reduce yield, tuber size, storability of tubers, quality of fresh-market and processing tubers and marketability of the crop.
Alternaria species cause dramatic leaf losses in growing potato crops which in turn can reduce yields by up to 30%.