ABSTRACT The rice stem borer (RSB), Chilo suppressalis (Walker), is a notorious rice pest that has led to substantial economic losses in the rice‐growing regions of China. To effectively manage this pest, it is crucial to study its population dynamics and seasonal genetic variations, particularly in the typical bivoltine area of northern China. Here, we monitored population dynamics via sex pheromone traps in rice fields in Shenyang, Liaoning Province, from 2019 to 2024. Additionally, we used 12 microsatellite loci to investigate temporal genetic variation and population genetic structure across nine populations collected from 2021 to 2024 (excluding 2022). Overall, our results revealed significant interannual and seasonal fluctuations in population abundance. The highest annual catch was recorded in 2022 (3159 individuals), and the lowest was recorded in 2023 (428 individuals). Seasonally, captures peaked in June, accounting for 54.31% ± 5.74% of the annual total, and were lowest in September (0.79% ± 0.42%). The average annual occurrence period of RSB was 94 ± 7.37 days. Population genetic analyses based on microsatellite markers revealed moderate genetic diversity and differentiation among populations. Bayesian clustering analysis revealed three genetically distinct groups, revealing an obvious temporal genetic structure. Our study provides critical insights into the occurrence patterns of RSB in Shenyang, Liaoning Province, and its temporal genetic dynamics in a representative bivoltine area of northern China. These findings challenge the static view of pest populations and underscore the need for temporally explicit, adaptive strategies in resistance monitoring and integrated pest management (IPM).
Gu et al. (Fri,) studied this question.