Early blight and black fruit rot
Agent: Alternaria solani
Symptoms
Usually appears when fruits begin to set. First affects the lower leaves, then the stem and fruits. Large brown or black spots with concentric rings appear on them. Around the spot, the leaf begins to yellow and dies. It also attacks potatoes and eggplants. The fungus is resistant and persists for several years.
Control and prevention
Remove and destroy affected parts. Prevention: drip irrigation, good ventilation, not too much humidity, resistant varieties. If attacked — fungicides.
Related problems
Similar symptoms might indicate a different cause — compare them.
Mold
Symptoms caused by various fungi. Mold only survives in high humidity.
Late blight
Phytophthora infestans
Dark green or black spots appear and spread on the edges of the leaves. The same can appear on the fruits.
Root Rot
Fusarium oxysporum
Common in tomato gardens. Thrives in warm, acidic soils. Infects the plant through the roots, spreads through the circulatory system. The first symptom is yellowing of the lower leaves; dark brown spots are found when the stem is cut. Can affect potatoes, peppers, eggplants.