Blight
Blight is 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:
Castanea mollissima
Chinese chestnuts have evolved over a long period of time in coexistence with the bark fungal disease chestnut blight ("Cryphonectria parasitica", formerly "Endothia parasitica"), and have evolved a very successful resistance to the blight, probably more so than any other species of chestnut, so that, although it is not immune, it typically sustains no more than minor damage when infected. It's important to realize, though, that Chinese chestnut trees vary considerably in blight resistance. Some individuals are quite susceptible while others are essentially immune to the disease. Japanese chestnut is also comparatively resistant to blight, with European chestnut somewhat less so. In the 1890s, Chinese and Japanese chestnuts were imported to the United States with the intention of utilizing them as orchard trees due to their small, compact size compared to the towering American chestnut. The results unfortunately were disastrous as the imported Asian species introduced blight to which "C. dentata" lacked any resistance. The disease was first noticed on a tree in the Brooklyn Zoo in 1902 and quickly spread all out of control, ravaging American chestnuts. Within 30 years, there were very few left in their native range. An active program has been pursued in North America to cross-breed the Chinese and American chestnuts to try to maximize various desirable traits of the American chestnut, such as larger stature, larger leaf size, larger nut size, and greater nut sweetness, while also isolating and carrying the blight resistance from the Chinese chestnut.