Blight is a group of plant diseases sharing a specific symptom caused by infection by a pathogenic organism, often a fungus.
Blight is a group of plant diseases sharing a specific symptom caused by infection by a pathogenic organism, often a fungus.
Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Diseases called blights include:
Blights are often named after their causative agent. For example, Colletotrichum blight is named after the fungus Colletotrichum capsici, and Phytophthora blight is named after the water mold Phytophthora parasitica.
When blights have been particularly large-scale and consequential in their effects, they have sometimes become named historical events. One such was the 19th Century European Potato Failure, known in Ireland as the "Great Famine". It was caused by a strain of potato blight, Phytophthora infestans.
Another was the near extinction of the Bermuda cedar during the 1940s and 1950s in the event described as The Blight or The Cedar Blight, caused by coccoid scale insects.
in the 1940s, two species of scale were accidentally introduced, and, unable to deal with this foreign pest, 95% of Bermuda's cedar trees were killed. The 5% of trees who survived the blight were found to be resistant to the scale. These have been propagated since then, and the Bermuda cedar survives today. Unfortunately the cedar was Bermuda's main tree cover up until the blight, with little diversity to fill the void when the trees died off. Thus, some species who depended on and thrived in its branches, such as bluebirds and white-eyed vireo became critically endangered along with it. Others, such as the endemic cicada went extinct without it.
An estimated 95 percent of the surviving population of native Bermuda cedar (Juniperus bermudiana) was destroyed between 1946 and 1951 (Rueger and von Wallmenich 1996), following the accidental introduction of two coccoid scale insects (Sterrer 1998a). Only an estimated one percent of the original cedar forest survived the blight (BBP 1997).
The accidental introduction of the Oyster-shell Scale and the Juniper Scale caused the demise of at least 85 percent of the cedar population by 1952, with more than 100,000 being felled during and after the scale infestation.
