Parasitic capacity of Chelonus bifoveolatus Szépligeti (Hymenoptera: Braconidae) on fall armyworm reared on maize, millet, and sorghum

Abstract

Several species of parasitoids associated with the fall armyworm, Spodoptera frugiperda , have been identified in Burkina Faso, among which Chelonus bifoveolatus , an egg-larval parasitoid, is the most abundant. This study was conducted in the region of Bobo-Dioulasso, Western Burkina Faso, from April 2023 to February 2024 under ambient laboratory conditions. The objective was to investigate the biological parameters of C. bifoveolatus reared on S. frugiperda on different host plants and at different periods of the year. Egg masses laid on maize, millet, and sorghum leaves were exposed daily to female parasitoids. The parameters studied included parasitism rate, cocoon formation rate, adult emergence rate, post-embryonic and cocoon development duration, sex-ratio, and lifespan. Parasitism rates varied between 48% and 80%, the pupation rate between 48.00% and 99.43% and the emergence rate between 27.60% and 84.91%. Post-embryonic development lasted between 14.18 ± 2.05 and 28.52 ± 2.87 days, while cocoon development ranged from 9.23 ± 1.18 to 21.29 ± 1.63 days. The sex ratio favoured males, with at least two males for every female. The adult lifespan ranged from 10.22 ± 3.74 to 13.34 ± 4.60 days. In general, performances did not vary much with host plants but were better during the rainy season than during the dry season. This study provides important information about C. bifoveolatus with a view to its use as a biological control agent of the fall armyworm.