Efficacy of entomopathogens against different life stages of Spodoptera frugiperda (J.E. Smith, 1797) (Noctuidae: Lepidoptera) under laboratory conditions

Abstract

A laboratory experiment was conducted in the Department of Entomology, College of Agriculture, OUAT, Bhubaneswar, during 2021–22 to evaluate the efficacy of various entomopathogens against different life stages of Spodoptera frugiperda (J.E. Smith, 1797) (Noctuidae: Lepidoptera), including eggs and second to sixth instar larvae. Topical application of Metarhizium anisopliae on eggs resulted in the highest reduction in hatchability (15%), followed by Beauveria bassiana and Metarhizium rileyi (12.5% each), while Bacillus thuringiensis showed no effect. In the leaf dip bioassay for larval instars, the efficacy of entomopathogens decreased with increasing larval age. Among second instars, B. thuringiensis exhibited the highest mortality (27.78%) at 120 hours after treatment (HAT), followed by M. rileyi (17.5%) and B. bassiana (15.56%). Third instar larvae were most affected by B. thuringiensis (25% mortality) and B. bassiana (15%), while fourth instar larvae showed maximum cumulative mortality with B. bassiana (15%) and moderate effectiveness of B. thuringiensis, M. rileyi, and M. anisopliae (12.5% each). Fifth and sixth instars demonstrated reduced susceptibility, with B. thuringiensis, M. rileyi, and M. anisopliae achieving only 10% mortality in the fifth instar and B. bassiana showing 5% mortality in the sixth instar.