Powdery Mildew
Agent: Erysiphe
Symptoms
Irregularly shaped white coating with deposits appears on the leaves, which later turn grayish. Drafts promote the disease.
Control and prevention
Remove affected parts, avoid drafts. Green soap helps. If attacked - fungicides.
Related problems
Similar symptoms might indicate a different cause — compare them.
Early blight and black fruit rot
Alternaria solani
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.
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.
Septoria Leaf Spot
Septoria lycopersici
Forms light spots with dark edges, with black dots inside. Later the leaf yellows and falls off. Does not affect fruits. The fungus is resistant, survives winter.