Biological control potential of Chouioia cunea (Hymenoptera: Eulophidae) in China, against the invasive pest Spodoptera frugiperda (Lepidoptera: Noctuidae): parasitism performance and multi-generation adaptability

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a globally invasive agricultural pest that poses a serious threat to crop production and has developed resistance to multiple insecticides. Developing effective and sustainable biological control strategies is therefore urgently needed. In this study, we evaluated the biological control potential of a native Chinese parasitoid, Chouioia cunea (Yang) (Hymenoptera: Eulophidae), against the pupae of S. frugiperda. Parasitism performance was assessed under different parasitoid-to-host ratios (1:1, 2:1, 3:1, and 4:1), followed by successive rearing for 8 generations to determine population stability. In addition, reproductive performance on S. frugiperda and Hyphantria cunea (Drury) (Lepidoptera: Erebidae) pupae was compared. Parasitism rate increased with parasitoid density and reached 80.00 ± 5.77% at a ratio of 4:1. Offspring production peaked at ratios of 3:1 and 4:1, with no significant difference between them. During successive generations, parasitism rate increased from F1 to F3 and remained stable (93.33% to 96.67%) thereafter, while developmental duration, offspring number, and sex ratio showed no significant decline. Compared with H. cunea, development on S. frugiperda pupae was significantly faster, whereas parasitism rate and reproductive output were similar. These results demonstrate that C. cunea can successfully parasitize S. frugiperda pupae and maintain stable multi-generation reproduction, indicating strong host adaptability and high potential as a biological control agent. This study provides a foundation for the application of this native parasitoid in the integrated management of S. frugiperda.