Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. It is simply a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this symptom are called blights. Several notable examples are:

  • Late blight of potato, caused by the water mold Phytophthora infestans (Mont.) de Bary, the disease which led to the Great Irish Famine
  • Southern corn leaf blight, caused by the fungus Cochliobolus heterostrophus (Drechs.) Drechs, anamorph Bipolaris maydis (Nisikado & Miyake) Shoemaker, incited a severe loss of corn in the United States in 1970.
  • Chestnut blight, caused by the fungus Cryphonectria parasitica (Murrill) Barr, has nearly completely eradicated mature American chestnuts in North America.
  • Fire blight of pome fruits, caused by the bacterium Erwinia amylovora (Burrill) Winslow et al., is the most severe disease of pear and also is found in apple and raspberry, among others.
  • Bacterial leaf blight of rice, caused by the bacterium Xanthomonas oryzae (Uyeda & Ishiyama) Dowson.
  • Early blight of potato and tomato, caused by species of the ubiquitous fungal genus Alternaria
  • Leaf blight of the grasses

On leaf tissue, symptoms of blight are the initial appearance of lesions which rapidly engulf surrounding tissue. However, leaf spot may, in advanced stages, expand to kill entire areas of leaf tissue and thus exhibit blight symptoms.

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Famous quotes containing the word blight:

    It is the blight man was born for,
    Gerard Manley Hopkins (1844–1889)

    We are naïve and moralistic women. We are human beings. Who find politics a blight upon the human condition. And do not know how one copes with it except through politics.
    Kate Millett (b. 1934)

    Some say that happiness is not good for mortals, & they ought to be answered that sorrow is not fit for immortals & is utterly useless to any one; a blight never does good to a tree, & if a blight kill not a tree but it still bear fruit, let none say that the fruit was in consequence of the blight.
    William Blake (1757–1827)