The ones described here are similar in that they do not have obvious fungal growth on either the leaf or the fruit spots. Early Blight Early blight is caused by Alternaria solani . The fungus causes disease in tomato, potato, eggplant, horse nettle, and black nightshade. First described in 1882, it is now found on all continents. It is very destructive in temperate humid climates.
Early blight can cause a decrease in fruit quantity and quality.
All aboveground parts of the plant can have symptoms of this disease. The fungus can kill seedlings before or after they break the soil surface. It can also cause collar rot in young plants, in which a dark, slightly sunken spot develops on one side of the stem. This spot will either grow completely around the stem or weaken the stem, causing the plant to fall over and die. They have a distinct pattern of concentric rings , like a target.