【摘要】 【目的】明确草地贪夜蛾Spodopterafrugiperda的耐寒性与越冬能力,进而分析其在福建省的越冬区和周年发生区。【方法】应用校正死亡率分析草地贪夜蛾在低温下的存活能力,利用机率值分析法计算草地贪夜蛾的LT50、LT90和LT99并评价其耐寒性;采用模拟越冬、田间挖蛹、成虫性诱及受害率调查观测法,结合气象资料分析草地贪夜蛾的越冬能力和周年发生区。【结果】低温对草地贪夜蛾具有明显的致死作用,在0、4和8℃下,试虫的死亡率随着温度的降低和处理时间的延长而上升,其致死时间(LT50、LT90和LT99)随之缩短。不同发育阶段的草地贪夜蛾在不同低温下的存活能力具有很大的差异。该虫的耐寒性以卵为最弱,蛹最强;1-3龄幼虫的耐寒性大于4-6龄的;雌成虫比雄成虫的耐寒性强。草地贪夜蛾卵在福州闽侯和晋安1-3月期间不能存活;在福州闽侯、三明大田和南平建瓯无冬玉米种植区的草地贪夜蛾越冬蛹中,一部分能在越冬过程中陆续羽化,但冬季羽化的成虫由于低温或缺乏适宜寄主植物不能繁殖,另一部分则逐渐死亡;而在福州晋安,有2.08%的蛹能存活越过3月15日从而完成越冬。在莆田仙游和漳州长泰2个冬玉米种植区,草地贪夜蛾低龄幼虫、蛹和成虫均可在全年最冷月的1、2月份发生。【结论】在草地贪夜蛾各虫态中,卵的耐寒性最弱,蛹的最强,在无冬玉米种植区,蛹是最有可能的越冬虫态。1-3月期间的环境温度决定草地贪夜蛾的越冬能力和周年发生区分布。在1-3月期间日均温≤12.6℃的地区,蛹不能完成整个越冬过程,其在≥14.2℃的地区可以完成越冬。草地贪夜蛾在1-3月期间日均温≥15.0℃的冬玉米种植区可以周年发生为害,低龄幼虫、蛹和成虫可能是其在冬玉米种植区的越冬虫态。更多还原

【Abstract】 [Objectives] To clarify the cold hardiness and overwintering ability of Spodoptera frugiperda and thereby predict its overwintering and year-round ranges in Fujian. [Methods] The ability of S. frugiperda to survive low temperatures was analyzed using corrected mortality data and the species’ cold hardiness evaluated using LT50, LT90 and LT99 values calculated by probability value analysis. Overwintering ability and regions of year-round occurrence were analyzed based on simulated overwintering with meteorological data, data on the number of pupae in soil, sex attractant trap capture results and the crop damage rate in fields. [Results] Low temperature had significant lethal effects on various life stages of S. frugiperda. At temperatures of 0, 4 and 8 ℃, mortality increased with decreasing temperature and exposure time. The duration of survival to the LT50, LT90 and LT99 treatments also decreased, regardless of the developmental stage. The ability of S. frugiperda to survive low temperatures varied greatly with temperature and developmental stage. Eggs and pupae had the lowest, and highest, cold hardiness, respectively. Among larval instars, the 1 st to 3 rd instars had greater cold hardiness than the 4 th to 6 th, and adult females had greater cold hardiness than adult males. Eggs should not survive between January and March in Minhou and Jin’an(Fuzhou). With respect to the winter viability of pupae in "no winter" maize regions, some pupae should successfully overwinter while others die gradually in Minhou(Fuzhou), Datian(Sanming) and Jian’ou(Nanping). However, adults that emerge in winter shouldn’t be able to reproduce due to the low temperature and absence of prefered host plants. Only 2.08% of pupae survived beyond March 15 th and completed overwintering in Jin’an(Fuzhou). Young larvae, pupae and adults occur in maize fields in January and February, the coldest months of the year, in Xianyou(Putian) and Changtai(Zhangzhou), the two winter maize planting regions in Fujian province. [Conclusion] Among the developmental stages of S. frugiperda, eggs and pupae have the lowest, and highest, cold hardiness, respectively. The pupa is therefore the most likely stage to overwinter in "no winter" maize regions. The regions where S. frugiperda is likely to overwinter and occur year-round are determined by the ambient temperature between January and March. Pupae can’t complete the entire overwintering process in regions where the average daily temperature is ≤12.6 ℃ between January and March, but can do so in regions where the average daily temperature is ≥14.2 ℃. S. frugiperda can damage maize crops year round in winter maize planting regions where the average daily temperature is ≥15.0 ℃ between January and March, and can overwinter as young larvae, pupae and adults in these regions.更多还原