【摘要】 小菜娥（Plutella。xylostella L.）广泛分布干世界各地。在杭州郊区,近年来上升为最重要的十字花科害虫。为害猖獗时可减产3—5成。 1973—1974年的研究表明,在杭州实验室条件下,小菜蛾一年可发生9—14代,世代重叠。在田间,各个季节都能见到四种虫态,没有越冬滞育现象。 成虫产卵期可以近于或长于下一代的幼期历期。这是世代重叠的一个重要因素。九月份达到世代重叠高峰,每旬七代重叠,而从整个九月份看,可有八代重叠。 在杭州室内最适气温条件下,发生一代仅需9—10天;而冬天完成一代却要110天。卵、幼虫和蛹的全年残存率分别为75.62％,80.21％和93.60％。 幼期历期与日平均温度间的曲线迴归方程为Y=1997X^-2.0625,Y=4345X^-2.0258,Y=2427X^-2.0025。更多还原

【Abstract】 The diamondbaek moth (Plutella xylostella L.) is a cosmopolitan species infesting cruciferous crops. Since the sixties, it has become an important pest on the cruciferous crops in our country, especially in the Yangtze River Valley, as well as southern and south western China, in spite of spraying with Dipterex and Dichlorphos. In order to find effective measures against this pest, we studied its biology from 1973 to 1976. This paper deals with its life history, annual generations and temperature relations.According to the results from laboratory rearing it has 9 to 14 generations a year in Hangchow, and approximately 20-30% of the moths produce 14 generations, a few (about 1-2%) 9 generations, and the rest between 9 and 14 generations. The maximal overlap of generations derived from a single pair reared from October occurred in the next September. Under the most favourable thermal condition it took only 9-10 days to complete a generation, whereas in the winter, it took 110 days. All the developmental stages can be found throughout the year in the field in Hangchow.The average survival rates of eggs, larvae and pupae throughout the year were found to be 75.6%, 80.2% and 93.6% respectively. Eegression equations of development time to temperature for egg, larval and pupal stages are Y’ = 1997X’-2.0625 Y’ = 4345X’-2.0258 and Y’ = 2427X’-2.0025 respectily.更多还原