plant disease, typically one caused by fungi such as mildews, rusts, and smuts, and by some bacteria

Blight refers to way plants wither when infected. It is usually caused by fungi, or viruses, or sometimes by bacteria.

The browned fruit has blight.

Blight is a rapid and complete chlorosis,[1] browning, then death of plant tissues such as leaves, branches, twigs, or flowers.[2] Various diseases which cause the symptom are known as blights. Several notable examples are:

  • Late blight of potato, caused by the water mould Phytophthora infestans, the disease which led to the Irish potato famine
  • Southern corn leaf blight, caused by the fungus Cochliobolus heterostrophus. This caused a severe loss of corn in the United States in 1970.[3]
  • Chestnut blight, caused by the fungus Cryphonectria parasitica has nearly eradicated mature American chestnuts in North America.
  • Bacterial leaf blight of rice is caused by the bacterium Xanthomonas oryzae.[4]
  • Early blight of potato and tomato, caused by species of the common fungal genus Alternaria.
  • Leaf blight of grasses. On leaf tissue, symptoms of blight are the initial appearance of lesions which rapidly engulf surrounding tissue.


  1. yellowing due to loss of chlorophyll
  2. Agrios, George N. 2005 Plant pathology. 5th ed, Burlington, MA: Elsevier Academic Press.
  3. Partridge J.E. Southern Corn Leaf Blight. 2003. 8 August 2006. Archived 2010-07-23 at the Wayback Machine
  4. Oda M. Sekizawa Y. and Watanabe T. 1966. Phenazines as disinfectants against bacterial leaf blight of the rice plant. Applied Microbiology 14(3):365-367.