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:
Halo blight
Toxin phaseolotoxin is produced, which acts as an irreversible inhibitor of ornithine carbamyltransferase (OTC), an essential enzyme involved in the conversion from ornithine to arginine, an amino acid which is utilized in the biosynthesis of proteins in plants. With presence of 30 pmol phaseolotoxin, it is able to reduce OCT activity to less than 20% of the one of unaffected OCT within, leading to arginine starvation and subsequently prohibiting protein synthesis. As a result, disease symptoms appear within 2 days, where chlorotic lesions appear as yellow halos surrounding black necrotic spots on the infected plants.