Efficacy of microbial bio-pesticides for management of Helicoverpa armigera (Hübner) in Sweet corn and their economics

The results exposed that the minimum larval population (2.05, 1.86 & 0.8 larvae/m²) was obtained in indoxacarb 14.5 SC at 3, 7 and 10 days after spraying followed by spinosad 45 SC (4.4, 3.6 & 2.6 larvae/m²) and emamactin benzoate 5 SG (5.8, 3.56 & 2.6 lervae/m²), respectively as against conventional insecticide profenophos 50% EC + cypermethrin 5% SC 8 which recorded 6.9, 4.95 and 3.5 larvae/m². The minimum larval population (5.9, 3.9 & 3.1 larvae/m²) was obtained in Beauveria bassiana (JNKVV) at 3, 7 and 10 days after spraying followed by HaNPV (6.2, 4.8 & 2.5 larvae/m²) and (6.4, 5.98 & 4.1 larvae/m²) was recorded in NSKE and maximum in Bacillus thuringiensis (7.4, 6.65 & 4.1 larvae/m²) at 3, 7 and 10 days after spraying, respectively. Indoxacarb was found significantly more effective in reducing the pod infestation (6.7%) in compared to spinosad (7.56%) and emamectin benzoate (7.9%) in 2014–15 and 2015–16. The highest cob yield 35.8 (000cob/ha), cost benefit ratio (2.9) and net profit 35887 was found in indoxacarb followed by spinosad (34.76, 000cob/ha, 2.7 B: C and net income 30148), emamectin benzoate (34.56 000cob/ha, 2.6 and net income 32084), profenophos + cypermethrin (32.5 000q/ha, 2.5B: C and net income 24261) and novaluron (14.5 thousand cob/ha, 2.3 B: C and net profit was 5540). The maximum percentage of increase was observed in the indoxacarb 184.2% and minimum in 17.1% in B. thuringiensis. It might be observed in the present demonstration that the age of plants, chemically synthesized pestisides or plant based or microbial biopesticides and time of the application of these either chemical or biological means was more important to enhance the yield of sweet corn in the field. Among the microbial biopesticides, significantly minimum (5.7 and 2.7, respectively, at 3&10 days) larval population and pod damage (13.5%) was found in HaNPV used treated plot.