Integration of Selective Insecticides with Metarhizium anisopliae for Sustainable Management of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in Maize
Spodoptera frugiperda (J.E. Smith) is a destructive invasive pest that poses a serious threat to maize production, necessitating the development of sustainable management strategies. The present study evaluated the efficacy of integrating selective insecticides with Metarhizium anisopliae for the management of fall armyworm under field conditions. Field experiments were conducted at two locations in South Gujarat, India, during the Rabi 2025–26 season using novaluron 5.25 + emamectin benzoate 0.9 SC and thiamethoxam 12.60 + lambda-cyhalothrin 9.50 SC applied alone and in combination with M. anisopliae, along with M. anisopliae alone and an untreated control. Repeated-measures mixed-effects analysis revealed significant treatment effects on plant infestation, leaf damage, cob infestation and cob yield. Among the evaluated treatments, novaluron 5.25 + emamectin benzoate 0.9 SC integrated with M. anisopliae recorded the lowest plant infestation (32.92%), leaf damage score (2.70) and cob infestation (11.01%), and produced the highest cob yield (13.21 t ha⁻¹), representing a 40.53% increase over the untreated control. Although statistically comparable with novaluron 5.25 + emamectin benzoate 0.9 SC applied alone for most parameters, the integrated treatment consistently showed numerically superior performance. In contrast, M. anisopliae applied alone provided only moderate suppression of fall armyworm and lower yield protection than insecticide-based treatments. These findings demonstrate that integrating M. anisopliae with selective insecticides improves fall armyworm management and maize productivity, highlighting its potential as an effective component of integrated pest management (IPM) for sustainable maize production.