Downy mildew is a cryptogamic disease caused by a pseudo-fungus of the Phytiaceae family. It is the main disease of potatoes, which can cause irreversible damage to crops.
It was responsible for the great famine which affected Northern Europe in the middle of the 19th century. Late blight is a disease that mainly affects nightshades: potatoes, tomatoes, eggplants, etc. The first signs of infestation of this disease generally appear after heavy rains, when the humidity exceeds 90%, followed by temperatures which oscillate between 10 and 25°C. The best way to fight this disease is therefore to adopt simple actions to limit humidity: water in the morning, avoid spraying the leaves as much as possible, so that the water has time to evaporate during the day. Respect the plant mulch to prevent it from forming; remove debris from forming. Spray a horsetailoction or a black soda solution of baking soda and baking powder on the leaves.