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:
Fungicide use in the United States
Leaf blight of almonds was first discovered in 1950, and by 1983 it had spread throughout the Sacramento Valley. Almond leaf blight is characterized by the death of leaves throughout the summer. The fungus interferes with water conduction in the leaf. In fall and winter, dormant buds are killed by an extension of the lesion and in the spring, flowers are killed. Repeated attacks of leaf blight, though rarely killing more than 20% of the leaves, ultimately reduce tree vigor. Experiments have shown that the use of ziram and captan can reduce the incidence of leaf blight by 75–80% in treated trees.