Efficacy of Nomuraea rileyi Against Different Instars of Spodoptera litura and Helicoverpa armigera*

The efficacy of Nomuraea rileyi against Spodoptera litura and Helicoverpa armigera larvae was tested. Early instar larvae of S. litura and H. armigera were more susceptible (80–95% in Ist and 2nd instars) to N. rileyi infection. Mortalities were higher at higher concentrations, however, 1 x 107 spores/ml was found to be more effective than other two higher concentrations viz., 1 x 10⁸ and 1 x 10⁹ in later instars. Good mortalities were obtained up to 3rd instar at lower concentrations also. Between the insects, the later instars of H. armigera were more susceptible than that of S. litura.