Biology of pulse beetle [Callosobruchus chinensis (L.)] and its reaction against greengram [Vigna radiata (L) R. Wilczek] varieties

A laboratory study was conducted to evaluate resistance/preference in six green gram varieties viz., RMG62, RMG-268, RMG-344, RMG-492, SML-668 and IPM-02-3 against the C. chinensis (L.). Different biological parameters of life cycle like, egg laying, percent adult emergence alongwith growth index and economically important parameters like, percent grain damage, weight loss and germination were also observed. The biology of C. chinensis was studied on SML-668 variety of green gram. Female beetles laid on an average 90.0 eggs with mean incubation period of 4.8 days, larval pupal period took on average of 29.4 days. Males lived for 6.2 days while females for 8.6 days. The mean developmental period was 33.7 days and the growth index recorded was 2.79 on SML-668 variety of green gram. The varieties, SML-668 was most preferred host for egg laying and maximum percent adult emergence while least preferred variety was recorded RMG-62 with minimum percent adult emergence. Variety RMG-62 was the also least preferred food for the C. chinensis with the lowest growth index of 1.57. The maximum seed damage up to (80.21%) and weight loss (17.47%) was observed in SML-668, while minimum seed damage (40.99%) and weight loss (10.49%) occurred in RMG-62. Germination per cent was recorded highest in RMG-62 and RMG-344 with 85.37% in both and was lowest in SML-668 with 65.44%. Variety, RMG-62 was found relatively less damaged or less preferred and can be used in integrated pest management programmes against C. chinensis during storage.