Late blight of tomatoes and potatoes is one of the most common diseases. In a couple of weeks, the entire crop may die, especially late varieties suffer.
The disease can manifest itself as brown spots on all parts of the plant (fruits, leaves, stems). Fruits can be affected at different stages of development. Sometimes on unripe fruits, dark brown spots of irregular shape appear. And it happens that late blight manifests itself only when the tomatoes begin to blush. Late blight also affects potatoes, so tomatoes and potatoes should be planted as far away from each other as possible, and their plant residues should be burned in autumn.
It is better to disinfect greenhouses in autumn with sulfur dioxide or a solution of copper sulfate. If late blight occurs in the greenhouse in the summer, then the top layer of soil 4-5 cm thick is removed from it. Use seeds that are at least 2 years old, during which time they are free from diseases. Choose early tomato varieties or late blight-resistant varieties. Pick the fruits at the stage of "wax ripeness", dip them for 10 minutes in a warm solution of potassium permanganate, then rinse with water, wipe dry, wrap each tomato in a separate piece of paper and store in this form.