Blight is a symptom of plant disease.
One day, your plant looks lush and healthy. The next day, several leaves are yellow and then turn brown. Stems, flowers, and branches also turn brown and then die. What can cause this sudden, severe damage? It might be blight.
Blight is a symptom
Blight is not a disease. It is what several different plant diseases look like. The initial symptoms appear suddenly and spread very quickly. Leaves, fruit, stems, and flowers can all be affected. The first symptom is tiny lesions on leaf tissue. This is where the bacteria or fungi first enter the plant, usually through small tears. The pathogens may also enter through vulnerable new growth. What starts out looking like leaf spot soon covers entire areas of a plant. Leaves and flowers suddenly lose all their green and turn pale yellow (chlorosis), followed by spotting, browning, withering, and dying.
Blight is most commonly seen on tomatoes and potatoes (nightshade family), and on apples and pears (pome fruits). Ornamental plants are not exempt. Here is a list of the most common blight diseases:
How to control blight
Since blight enters plants through wounds and tender new growth, there are three ways you can reduce the likelihood of blight occurring in your garden:
These are especially important when temperatures of 75° to 85°F are expected to be accompanied by rain. Pruning and feeding stimulate new growth that cannot defend itself. Also, do not irrigate trees while they are in flower. Monitor plants closely after these conditions have occurred and completely remove and destroy any infected tissue. This means cutting several inches below infected tissue, using pruners that are sanitized with a household cleaner, such as Lysol, between each cut. This reduces the spread of the disease. Blossom sprays can be used on trees that have experienced blight in the past. Fixed copper sprays may provide some protection.
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