Efficacy of Entomopathogenic Nematode, Steinernema abbasi PN-1 against Helicoverpa armigera Hubner

The experiment was conducted during May 2022 at College of Agriculture, G. B. Pant University of Agriculture & Technology, U. S. Nagar, Pantnagar, Uttarakhand, India. The Steinernema abbasi PN-1 is a local isolate of entomopathogenic nematode isolated from the soil collected from Uttarakhand, India. Under the present study, virulenceof Steinernema abbasi PN-1 against different stages of Helicoverpa armigera Hubner were tested. Virulence studies of S. abbasi PN-1 against H. armigera proved that all larval stages and pupae of H. armigera were found susceptible to the IJs of S. abbasi PN-1. There was a positive correlation between insect mortality and the nematode concentration. The S. abbasi PN-1 caused 100% larval mortality at 48–60 h of post treatment in all tested doses in laboratory. Among the larval instars, 4^th instar larvae of H. armigera were more susceptible with a median lethal concentration (LC₅₀) value of 24.37 IJs larva^-1 and the median lethal time (LT₅₀) values of 25.63 hours. The 2^nd instar larvae was least susceptible with an LC₅₀ value of 78.96 IJs larva^-1 and LT₅₀ values of 41.33 hours. The pupal stage was less susceptible than the larval stage with the LC₅₀ value of 98.3 IJs larva^-1. Our results showed that S. abbasi PN-1 can be used as efficient biological control agents against H. armigera with further field studies.