草地螟在5种寄主上的实验种群生命表

Life tables for experimental populations of Loxostege sticticalis(Lepidoptera:Crambidae)on five host plants

草地螟（Loxostege sticticalis Linnaeus）是一种世界性害虫,也是我国华北、西北以及东北地区农牧业生产的重要害虫。本试验在（26＋1）℃,RH 70%~80%,L∥D=16h∥8h条件下组建了草地螟在藜、大豆、苜蓿、甜菜和向日葵叶片的实验种群生命表,以研究草地螟的危害差异性,为草地螟的防治提供基础数据。结果表明,草地螟的生长发育、繁殖和生命表参数等在不同寄主之间存在差异。藜组卵的发育历期最短（2.42d）、甜菜组的最长（3.90d）;幼虫发育历期以甜菜组的最短（10.00d）,苜蓿组的最长（12.63d）;蛹的发育历期以向日葵组的最短（11.30d）,苜蓿组的最长（16.00d）;雌成虫产卵量以藜组最高（345.00粒/雌）,苜蓿组最低（138.83粒/雌）,雌成虫产卵期以藜组最长（10.42d）、苜蓿组最短（6.58d）。雌蛾产卵量呈现明显的动态变化：取食藜组和向日葵组雌蛾的产卵高峰出现在羽化后第8天,大豆组为羽化后第10天,苜蓿组为羽化后第7天和第9天,甜菜组为羽化后第6天和第10天。藜、大豆、苜蓿、甜菜和向日葵处理间草地螟的种群净增殖率（R0）、内禀增长率（rm）和周限增长率（λ）分别在59.772 8~169.194 1、0.097 6~0.135 2和1.102 5~1.144 8之间,其中以藜组的R0、rm和λ最大,苜蓿组的R0、rm和λ最小;平均世代周期（T）和种群加倍时间（t）的范围分别为37.508 0~41.915 8d和5.126 5~7.101 4d。综合比较5种寄主植物,认为藜是草地螟的最适宜寄主,其次分别为大豆、甜菜、向日葵、苜蓿。

The beet webworm,Loxostege sticticalis（L.）,is a worldwide insect which has become one of the major disastrous pests of economic crops in the northern,northwestern and northeastern China.In order to elucidate the occurrence and damage of L.sticticalis and offer basic data for control of this pest,the life tables for the experimental populations of L.sticticalis were established at the temperature of（26±1）℃,relative humidity of70%-80% and photoperiod of 16L：8D on lambsquarter,soybean,alfalfa,sugarbeet and sunflower leaves,respectively.The results indicated that the egg development was the shortest on the lambsquarter（2.42 d）and longest（3.90 d）on the sugarbeet.The larvae fed on the sugarbeet had the shortest developmental（10.00d）,while on the alfalfa,the longest developmental duration（12.63 d）.The pupal period（11.30 d）was shortest on the sunflower but longest（16.00d）on the alfalfa.The female adult fecundity and period of oviposition were the highest（345.00eggs/female,10.42 d）on the lambsquarter,whereas the lowest（138.83 eggs/female,6.58 d）on the alfalfa.The adult female oviposition showed obvious dynamics.The egg-laying peaks appeared in the eighth day after eclosion on the lambsquarter and sunflower,the 10 th day on the soybean,the seventh and ninth day on the alfalfa,the sixth and 10 th day on the sugarbeet.The life-table parameters of L.sticticalis were established by calculating the immature developmental time,the survival rate at mature and the adult reproductive stage.The net reproductive rate（R0）,the innate capacity for increase（rm）and the finite rate of increase（λ）varied from59.772 8 to 169.194 1,0.097 6 to 0.135 2 and 1.102 5 to 1.144 8,respectively,with R0,rm andλhighest onlambsquarter and lowest on alfalfa plants.The mean generation time（T）and the doubling time（t）varied from37.508 0 d to 41.915 8 d and 5.126 5 d to 7.101 4 d,respectively.By comprehensive comparison of five host plants,lambsquarter was considered the most appropriate host,followed by soybean,sugarbeet,sunflower and alfalfa.