Potato blight (sometimes referred to as late blight) and tomato blight are serious diseases of these two crops. They spread rapidly on the foliage and then affect the potato tubers or tomato fruit, resulting in a total rot, making them inedible. The affected potatoes and tomatoes taste disgusting, so don’t attempt to eat them.
Blight is specific to potatoes and tomatoes, but may sometimes attack some closely related ornamental Solanum species, such as Solanum crispum and petunias.
Attacks can start from June onwards, and are very dependent on the weather – temperature and humidity. When these are correct, the disease becomes very widespread and devastating, which is why blight is always worse in a warm, wet summer.
Blight was responsible for causing the Irish potato famine in the 1840s.