blight

blight, general term for any sudden and severe plant disease or for the agent that causes it. The term is now applied chiefly to diseases caused by bacteria (e.g., bean blights and fire blight of fruit trees), viruses (e.g., soybean bud blight), fungi (e.g., chestnut blight), and protists (e.g., potato blight). Other plant afflictions (caused by insects or unfavorable climatic conditions) that display similar symptoms are also called blights. See diseases of plants.

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blight

Any of various plant diseases whose symptoms include sudden and severe yellowing, browning, spotting, withering, or dying of leaves, flowers, fruit, stems, or the entire plant. Usually the shoots and other young, rapidly growing tissues of a plant are attacked. Most blights are caused by bacteria or fungi (see fungus); some result from drought. Fungal and bacterial blights are most likely under cool, moist conditions. Most economically important plants are susceptible to one or more blights. Measures taken to fight blight include destroying the infected plant parts; using disease-free seed or stock and resistant varieties; rotating crops (see crop rotation); pruning and spacing plants for better air circulation; controlling pests that carry the fungus from plant to plant; avoiding overhead watering and working among wet plants; and, where needed, applying fungicides or antibiotics. Maintaining sanitary conditions is the most important measure for stopping the spread of the infestation. See also chestnut blight.