滇东北菜区小菜蛾种群发生特征及其关键影响因子

Population dynamics and factors influencing the abundance, of Plutella xylostella L. in northeastern Yunnan

【目的】为掌握滇东北菜区小菜蛾Plutella xylostella (L.)种群发生消长特点,开展田间种群变化与气温、降雨和种植模式的关联性研究。【方法】利用性信息素诱集和田间系统调查开展小菜蛾成虫、幼虫种群消长动态监测。【结果】(1)滇东北菜区小菜蛾可全年发生,成虫发生呈现2个发生主峰期:3-7月春夏峰和9-11月秋峰,其中春夏是小菜蛾发生主峰,最高诱集量达971头/月.盆或板,持续时间和成虫量均比秋峰明显。幼虫种群消长主要表现为4-7月的春夏单峰型,最高虫量可达1.75头/株。(2)监测点月平均气温-2.4-21.8℃,全年降雨量317-872mm,小菜蛾田间成虫种群发生量与气温变化显著相关(r=0.315^**),与降雨量微弱相关(r=0.168);幼虫种群量与气温、降雨量微弱相关(r=0.270和r=0.296)。因此,滇东北菜区小菜蛾成虫和幼虫种群发生消长与十字花科蔬菜生长期相吻合。【结论】滇东北菜区气温、蔬菜品种布局和春夏种植模式是影响小菜蛾种群构建与消长的关键因子。

[Objectives] To understand the population dynamics of Plutella xylostella(L.) in the vegetable growing areas of northeastern Yunnan. [Methods] The relationships between population size and temperature, rainfall and planting pattern,were quantified and analyzed. Sex pheromone trapping and field surveys were used to monitor the population dynamics of adults and larvae, respectively. [Results] P. xylostella occurred year-round in northeastern Yunnan. The adult population has two major peaks in the spring and summer, from March to July, and minor peaks in autumn, from September to November. The maximum number of adults trapped was 971 per month per card in the spring-summer season, significantly higher than the number caught during the autumn peak of abundance. Larvae have a single peak of abundance in spring and summer, from April to July, during which the highest abundance was 1.75 larvae per plant. The average monthly temperature in northeastern Yunnan was-2.4-21.8 ℃, and annual rainfall was 317-872 mm. The abundance of the adult population was significantly correlated with temperature(r=0.315^**), which was weakly correlated with rainfall(r=0.168). Larval population abundance was also closely correlated with temperature and rainfall(r=0.270 and r=0.296). The population dynamics of both adults and larvae were also consistent with the cultivation patterns and growth periods of cruciferous vegetables. [Conclusion] Temperature and spring–summer planting patterns of vegetables are the main factors affecting the population structure and abundance of P.xylostella in northeastern Yunnan.