Ecology, Environment and Conservation Paper

INFLUENCE OF ABOTIC FACTORS ON POPULAUON ABUNDANCE OF SOME COMMON PESTS IF FLICEBEAN, VIGNA UMBELIATA

Y.S. Rathore, S.S. Lal and A. Bhattacharya

Abstract

Ricebean [Vigna umbellata (Thun.) Ohwi and Ohashi] was grown during rainy seasons of 1992 and 1993 and ratoon crop during summer season of I 995. Abundance of major insect pests and their relationships with weather parameters were observed at standard weekly basis. Through estimates of correlation, regression, per cent accountability of pest population and multiple regression, it was noted that the effect of various weather parameters differed with different pest. Amongst weather parameters effect of maximum and minimum temperature were most profound and were followed by morning and evening RH on the population size of all insects except semilooper. Whitefly population increased with increase in minimum temperature, whereas population of leaf hopper decreased. Pod weevil and thrips had negative association with all weather parameters. Wind velocity has its effect on population size of thrips on foliage as well as on flowers. Coefficient of determination for insect population ranged between 0.08 and 0.62.