Effects of Three Sweet Potato Varieties on the Development, Survival, and Reproduction of Spodoptera frugiperda Based on an Age-Stage, Two-Sex Life Table Analysis

To examine how host plant identity shapes the performance of the invasive pest Spodoptera frugiperda (J.E. Smith), three sweet potato varieties (Qianshu 12, Qianshu 17, and Yushu 13) were evaluated under laboratory conditions, with maize (Xida 818) as a control. Development, survival, reproduction, and population parameters were assessed using an age-stage, two-sex life table approach. The results demonstrated that S. frugiperda completed its life cycle on all sweet potato varieties. The developmental period was significantly different in the larval stage. S. frugiperda fed with Yushu 13 had the longest pupal duration (9.97 d) and preadult duration (37.94 d). Reproductive performance was also reduced on sweet potato: adults reared on maize showed greater longevity and higher fecundity, whereas no significant differences were found between Qianshu 17 and Yushu 13. Survival patterns differed among host plants and developmental stages. Early instar survival was highest on Qianshu 12 but lowest on Yushu 13, and Qianshu 12 supported relatively higher survival from late larval stages to adulthood. Life table analysis further showed that larvae fed with three sweet potato varieties exhibited a lower net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), and longer mean generation time (T) compared to those fed with corn. Overall, although sweet potato can support the development of S. frugiperda, it constrains reproduction and population growth, indicating lower host suitability.