A fungal disease of potato caused by Alternaria solani, manifesting as dry spots with characteristic concentric zoning. The disease is widespread, affecting primarily the lower leaves during the budding stage.
In the reference
123
varieties
crop Potato,
where this is mentioned in the description.
The causal agent of the disease is the imperfect fungus Alternaria solani. Symptoms appear as dark brown or brownish round-to-angular spots, which often have a "target" pattern due to concentric zoning. Under high humidity, affected tissues undergo necrosis and leaves may die prematurely, with a velvety olive-colored bloom of conidia often visible on the spots.
Unlike late blight, the pathogen of early blight does not have a distinct race structure but displays variability in isolate aggressiveness. Resistance of potato cultivars to the pathogen is quantitative and polygenic in nature; specific R-resistance genes have not been identified to date, which is why field resistance scoring is used in breeding.
Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.