Efficacy of Biorational Compounds against Whitefly (Bemisia tabaci Genn.) on Blackgram (Vigna mungo L.)

Bio-rational compounds were evaluated against the field population of whitefly on blackgram in randomized complete block design replicated thrice during rainy season of2012/13 and 2013/14 at GLRP, Rampur, Chitwan, Nepal. Altogether eight treatments, i.e. Rapid (Acetamiprid 20% SP) @ 0.5 gm/lt of water; Spinosad, (Tracer 45% SP) @ 0.25 ml/lt of water; Fighter (Cypermethrin 10% EC + Chloropyrifos 50% EC) @ 1.5 ml /lt of water Admire (Imidacloprid 25% WP) @ 0.25 g/lt of water, Nepal pepper (Xanthoxylum armatum DC.) fruit extract @ 1:5 part; Neem (Azadirachta indicaA. Juss.) leaves extract @1:5 part; Jadu (Triazophos 25% EC + Deltamethrin 1% EC) @ 0.5 ml/lt of water; and one control (water spray) were selected for the experiment. Cumulative mean efficacy on population reduction over control, after third sprays indicated that spinosad (72.96%) and admire (60.97%) was very effective followed by jadu (59.54%), fighter (58.49%), and rapid (51.42%) with moderate efficacy. Neem (35.56%) and Nepal pepper (36.31%) extracts were the least effective in controlling whitefly population. The highest cost benefit ratio was found in plot treated with spinosad i.e. 1:2.7 followed by admire treated plots 1:2.6.