Blight is caused by fungi, and can causetremendous devastation in crop plants if it is not treated in time. There are two main blight types, early blight which is caused by the Alternaria solani fungus, and late blight which is caused by the Phytophthora infestans fungus. Infected plants develop brown spots on their leaves and tubers, resulting in yellowing, drying leaves and rotting, foul-smelling tubers. Blight treatment can be rather difficult, as the disease spreads quickly, the fungi spores being carried around by wind; the disease is particularly prevalent in cool, humid and wet seasons.
It is a good idea to try to prevent blight from happening in the first place, although, of course, this is not always possible. Ensuring that the soil is nutrient-rich and has sufficient lime in it can help discourage the blight fungi. Spraying the plants with anti-fungal sprays will also help. There are now many plant cultivars that are resistant to fungi attacks and using these can make for effective blight control. Watering plants at their base instead of showering them with sprays can also prove effective, as can mulching.
It is also important to keep checking the plants for signs of blight, and if blight does take hold despite all precautions, the infected leaves should immediately be removed and disposed to keep the fungi from spreading. Washing hands between handling different plants is advisable. The disposed leaves are better off being burnt than added to the compost pile; adding to the compost pile can increase the chances of the fungi being spread. Blight lingers in the soil, so it may help to plant new plants in a new area.
In the case of tubers, keeping them well-covered with earth and not leaving any in the ground when they are harvested can help prevent blight. If infection has already occurred, the infected tubers will need to be dug out and burnt. It is important to check each tuber for signs of blight when storing, as even a single one with blight can spoil the rest of them.
Copper-based fungicides like Bordeaux mixture can be used as blight remedies in late blight treatment, but these should be used with caution. They may cause adverse reactions on human skin and eyes. Inorganic fungicides like neem oil and Dithane® are safer options for blight treatment, but are generally more effective as preventive blight control measures than as treatment for an infection that is already in advanced stages.