Vol. 12, Special Issue 8 (2023)

A number of insect pests attack soybean crop which is one of the factor that affect its productivity. Pests control by chemical pesticides requires high production cost resulting in a low profit of soybean farming; therefore, it is less favourable to farmers. The study aims to evaluate the economics of utilizing combination of microbial insecticides for management of lepidopterous defoliating pests of Soybean in Manipur. The research was conducted during the kharif season of 2022-23 with recommended soybean variety of Manipur, JS-335 at Agricultural Research Farm, Andro of Central Agricultural University, Imphal, Manipur. Six combination of commercial microbial formulations viz., combination of Beauveria bassiana, Metarhizium anisopliae, Nomuraea rileyi and Bacillus thuringiensis (Bt Commercial) were applied three times at 40, 60 and 80 days after sowing with half of the standard doses of respective microbial formulations. Recommended chemical insecticide Chlorantraniliprole 18.5% SC and untreated control treatment were included as standard check treatments. Upon crop maturity, data on numbers of pods per plant, weight of pods per plant, 100 seed weight and seed yield per plot were recorded. The incremental cost benefit ratio was calculated on the basis of prevailing cost of inputs and grain yield. Among the microbial combination, the highest incremental cost benefit ratio was obtained with treatment combination of fungus and bacteria i.e., Beauveria bassiana (500 ml/ha) + Bt commercial (500 ml/ha) (1:8.21) and Nomuraea rileyi (500 ml/ha) + Bt commercial (500 ml/ha) (1:8.14). The lowest ICBR of 1:5.38 was obtained with combination treatment of fungal formulations of Beauveria bassiana (500 ml/ha) + Metarhizium anisopliae (500 ml/ha).