Biocontrol potential of native microbial strains in the management of major lepidopteran pests infesting soybean

Abstract

Soybean is the most important oilseed and pulse crop being grown in Northern Karnataka. Lepidopteran pests are major threats in decreasing the yield of the crop. So, upon consequences of using chemical insecticides, biocontrol approach is the alternate tool for managing these insect pests, which is environmental friendly and ecologically feasible in nature. The present experiment was carried out in soybean under field conditions during Kharif, 2022 and 2023 at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad-Karnataka to assess the Biocontrol potential of native microbial strains against major lepidopteran pests of soybean. Five actinobacterial isolates were evaluated along with one entomopathogenic fungus, Metarhizium rileyi (2.00 g/l) and spinosad 45 SC (0.2 ml/l) as a standard check. The pooled results revealed that, Streptomyces hyderabadensis (200 ml/l) has emerged as the best isolate in controlling the four lepidopteran pests of soybean during both the years of investigation which recorded lowest mean population of S. litura (2.32 larvae/mrl) Thysanoplusia orichalcea (2.52 larvae/mrl), Spilosoma obliqua (1.17 larvae/mrl) and Cydia ptychora (1.04 larvae/ 5 pods) followed by Streptomyces xiaminensis (200 ml/l). The highest soybean yield reflected with the superior isolate, S. hyderabadensis (200 ml/l) with 18.17 quintals per hectare. The secondary metabolites produced by these actinobacterial strains made them as a potential biocontrol agent in controlling the lepidopteran pests in soybean ecosystem.