Quality assessment of Telenomus remus successively reared on Spodoptera litura eggs for 30 generations.

Background: Telenomus remus (Nixon) is a dominant natural enemy controlling the invasive pest Spodoptera frugiperda (J. E. Smith). Continuous rearing of egg parasitoids on alternative hosts is crucial for mass production and cost reduction. However, to ensure the effectiveness of natural enemy products against target pests in the field, it is necessary to evaluate the parasitoid quality during the mass-rearing process. Despite the successful rearing of this parasitoid on the alternative host Spodoptera litura (Fabricius) eggs, less attention has been paid to the quality of parasitoids continuously reared for multiple generations. Therefore, we evaluated the performance of T. remus reared on S. litura eggs for 30 generations via morphological characteristics, flight ability, and life table analysis.

Results: Wing length, wing width, body length, and right hind tibia length of T. remus did not differ among the different generations. However, the body length of female parasitoids was significantly longer than that of males for any generation. Although the proportion of 'flyers' and 'deformed' T. remus varied among generations, the flight ability did not decline significantly after rearing on S. litura eggs. Moreover, T. remus continuously reared on S. litura eggs maintained stable parasitism performance and life table parameters on the target host S. frugiperda eggs.

Conclusion: S. litura eggs are suitable hosts for the mass-rearing of T. remus. This study can be subsequently used to guide the production and facilitate the application of T. remus in the control of S. frugiperda. © 2023 Society of Chemical Industry.