Fitness Cost of Chlorpyrifos Resistance in <i>Spodoptera frugiperda</i> (Lepidoptera: Noctuidae) on Different Host Plants

Abstract Spodoptera frugiperda (J. E. Smith, 1797) is a polyphagous pest of global relevance due to the damage it inflicts on agricultural crops. In South American countries, this species one principal pests maize and cotton. Currently, S. also emerging as an important soybeans winter cereals in Brazil. Chemical control main tactics against frugiperda, even though resistance numerous modes action insecticides has been reported. To support insect management programs, we evaluated fitness costs acetylcholinesterase inhibitor chlorpyrifos. Fitness were quantified by comparing biological parameters chlorpyrifos-resistant -susceptible their F1 hybrids (heterozygotes) non-Bt cotton, maize, soybean, oats. The results revealed that genotype showed lower pupa-to-adult egg-to-adult survivorship reduced larval weights oats; longer neonate-to-pupa developmental periods, pupal fecundity maize; soybean; cotton compared with chlorpyrifos-susceptible genotype. affected fertility life table resistant genotype, increasing mean length generation reducing potential for population growth all hosts. These findings suggest at individual levels chlorpyrifos indicating removal selective agent from environment would result opportunities restoration susceptibility.