Assessment of quantitative yield loss of blackgram (Vigna mungo (L.) Hepper) due to urd bean leaf crinkle virus

Blackgram (Vigna mungo (L.) Hepper) also known as urdbean is a valuable source of protein in human diet. The crop suffers from variety of viruses. Among the viral diseases Urd bean Leaf Crinkle Virus (ULCV) causes economic yield losses. Significant differences in yield and yield parameters were observed between healthy and diseased plants when the infection occurred before flowering i.e., up to the age of 40 to 45 days under natural conditions. The plants infected with ULCV are shown to yield 85.67 per cent less than the seed yield of healthy plants. The seed yield is affected mainly by reduction in the number of pods/plant, number of seeds/pod and 100 seed weight. The overall plant growth as evidenced by 45.09 per cent reduction in plant height and 44.57 per cent reduction in number of trifoliate leaves/ plant than the healthy plants.