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:
Bitter pit
Bitter pit is a disorder in apple fruits, now believed to be induced by calcium deficiency. It occurs less commonly in pears.
The disease was probably first reported in Germany where it was known as "Stippen". It was also known as "Baldwin spot" and "blotchy cork" in North America. The name "bitter pit" was first used by Cobb in Australia in 1895. The disease has been shown as non-pathological and is now known as a disorder. When it occurs on the tree, it is known as "tree pit"; it may also occur in storage, when it is known as "storage pit".