Angular Black Spot Disease of Mung Beans

Abstract

SEVERE leaf spot disease on mung bean (Phaseolus radiatus L.) was observed near Banaras, India, during the months of September and October when the plants were just reaching maturity. The infection spots appeared mostly on lower leaves and could be easily mistaken on the basis of field symptoms for Cercospora cruenta occurring on the same host. Infection spots first appear as pale green angular spots, gradually deepening in colour, finally turning purplish-black to opaque (Fig. 1). The spots are usually 4–6 mm. × 3–6 mm., often coalescing to form patches. There was no indication of the diseased leaves showing premature drying up.