Leaf blight refers to any disease afflicting plants in which portions of the leaves become discolored, dried out, or dead. While leaf blight is most often fungal in nature, bacterial blight also exists. Leaf blight can affect nearly any plant with leaves.
Fungal plant diseases can cause a variety of symptoms, of which blight is only one. Blight is characterized by plant tissues that are dry or dead, but not rotten. Blight can strike different areas of the plant. In addition to leaf blight, fungal infection can cause stem blight and blossom blight, for example.
Bacterial leaf blight can affect beans, rice, cotton, tomato, pepper, soybean, and cassava. Different bacterial strains affect different plants. Bacterial blight on leaves is characterized by waterlogged spots on the plant's leaves that eventually turn brown or black, followed by the leaves falling off prematurely. In rice, the spots on the affected leaves turn white rather than black in their final stages.
Leaf blight, whether fungal or bacterial in nature, can be prevented by proper care of crops. Crops that are too crowded, or planted in soil that lacks nutrients, or is not regularly sanitized are susceptible to blight. To prevent blight, first select plant cultivars that are resistant to fungal and bacterial infection. Plant the seeds according to the guidelines for the plant to ensure that each plant receives adequate air flow and light. Prune foliage if it becomes overcrowded.
Make sure the soil you plant in is well-balanced nutritionally, and maintain it properly. Practice regular fertilization and sanitation, and make sure the soil has adequate drainage, as overly moist soil can lead to bacterial infection of the plants. Also, practice crop rotation, alternating non-related crops each season.
One of the most frequent causes of blight is contamination from other plants. Take care not to plant infected seeds or plants. If you find plants with blight, remove them and dispose of them properly. Also, practice weed control and insect control. Insects can be carriers of bacterial infection.
To keep your plants healthy and free of blight, there are a number of preventative solutions you can spray on your plants that are both natural and inexpensive. Lemongrass and mint extract help prevent both fungal and bacterial infection. Fungal blight on leaves can also be prevented with applications of aloe, animal urine, baking soda, basil, compost tea, copper, coriander, garlic, ginger, horsetail, horticultural oil, malabar nut, milk, neem, onion, papaya, pongam, soap, sulfur, or turmeric.