Morphology of immature Meteorus pulchricornis (Hymenoptera: Braconidae) and the biological control potential for Spodoptera frugiperda (Lepidoptera: Noctuidae)

Spodoptera frugiperda (J. E. Smith), an invasive pest, poses a major threat to agricultural productivity and food security in China. This study evaluated the biological control potential of the native parasitic wasp Meteorus pulchricornis (Wesmael) against third-instar S. frugiperda larvae. We examined the developmental dynamics of M. pulchricornis under different temperatures, its functional response to varying host densities, lifetime parasitism capacity, and larval morphological characteristics. Results showed that increasing temperature accelerated development but reduced emergence rates, with optimal performance at 26 °C. Functional response analysis indicated a Type II model, with parasitism escalating as host density increases before reaching saturation. Adults exhibited a continuous parasitism period of up to 22 days and parasitised an average of 131 hosts throughout their lifespan. Semi-field trials further confirmed its capacity to suppress S. frugiperda populations, achieving a 90.8% larval reduction and 52.0% corrected control efficacy, with parasitism and cocoon formation rates of 60.4% and 54.2%, respectively. Collectively, this study provides the first comprehensive evaluation of the development, parasitic capacity, and field efficacy of M. pulchricornis against S. frugiperda in China, offering crucial insights for its application in integrated pest management.