【目的】 本研究通过不同低温时长和低温所处发育阶段对小菜蛾Plutella xylostella生存和繁殖能力的影响，为冬季蔬菜大棚中小菜蛾的发生及防治提供理论参考。【方法】 在相对湿度为55%±10%，12L∶12D的光周期条件下，观察小菜蛾4龄幼虫、蛹和成虫分别经低温（8 ℃）处理24、48和96 h后幼虫的化蛹率、成虫的羽化率、成虫寿命、产卵前期、产卵期及产卵量等指标，以温度为（26±1）℃的处理为对照组。【结果】 8 ℃处理不同时长对小菜蛾幼虫化蛹率的影响差异不显著（χ² = 1.58，P = 0.664），但低温所处的不同发育阶段（χ² = 202.52，P < 0.001 和低温处理时长（χ² = 141.83，P < 0.001）显著影响成虫的羽化率；4龄幼虫低温处理后的羽化率均高于蛹期低温处理的（4龄幼虫低温：87.40%；蛹期低温：66.97%）。成虫寿命受低温处理时长（χ² = 39.3，P < 0.001）和低温所处发育阶段（χ² = 43.0，P < 0.001）影响。一定范围内，4龄幼虫低温处理时长对雌雄成虫寿命无显著影响（雌虫：χ² = 41.86，df = 3，P = 0.330；雄虫：χ² = 4.55，df = 3，P = 0.210），而蛹期（雌虫：χ² = 41.86，df = 3，P < 0.001；雄虫：χ² = 14.30，df = 3，P < 0.001）和成虫期雄虫寿命（χ² = 19.32，df = 3，P < 0.001）随低温处理时长的延长而逐渐延长；雄成虫寿命普遍长于雌成虫寿命（未成熟阶段低温：χ² =﹣3.88，P < 0.001；成熟阶段低温：χ² =﹣5.72，P < 0.001）；产卵前期随低温处理时长的延长而延长（未成熟期处理：χ² = 14.40，df = 3，P = 0.002；成熟期处理：χ² = 60.04, df = 2, P < 0.001）。单雌产卵量除蛹期8 ℃处理96 h（40.9粒/雌）外，其余处理与对照组（87.3粒/雌）相比无显著性降低。【结论】 不同低温处理时长对蛹的生存和繁殖的影响比对4龄幼虫的影响更为明显，且随低温处理时长的延长，对小菜蛾的生存和繁殖的抑制程度加深。

[Objectives]  To investigate the effects of exposing different developmental stages of Plutella xylostella to different durations of low temperature on the survival and reproductive capacity of this species, thereby providing a reference for predicting and preventing the occurrence of this pest in greenhouses in winter. [Methods]  The pupation rate, eclosion rate, adult lifespan, adult pre-oviposition period, oviposition period, and fecundity per female of P. xylostella were recorded under laboratory conditions of 55%±10% relative humidity and a 12L∶12D light cycle. Fourth instar larvae, pupae and adults were exposed to 8 °C for 24, 48 and 96 h. A control group was kept at (26±1)℃. [Results]  Irrespective of the duration, cold exposure did not significantly change the pupation rate of P. xylostella (χ² = 1.58, P = 0.664). However, development stage (χ² = 202.52, P < 0.001) and the duration of cold treatment (χ² = 141.83, P < 0.001) significantly affected the emergence rate. The effect of cold exposure on the emergence rate was higher for 4th instar larvae than for pupae (4th larval instar: 0.874 0; pupal stage: 0.669 7). Adult lifespan was affected by both the duration of cold exposure (χ² = 39.3, P < 0.001) and developmental stage (χ² = 141.83, P < 0.001). Within a certain range, the duration 4th instar larvae were exposed to cold had no significant effect on the life span of male and female adults (females: χ²= 41.86, df = 3, P = 0.330；males: χ² = 4.55, df = 3, P = 0.210), whereas the effect of cold exposure on the life span of both sexes was increased by the duration of cold exposure during the pupal stage (females: χ² = 41.86, df = 3, P < 0.001; males: χ² = 14.30, df = 3, P < 0.001). The longevity of adult males was also increased by increasing the duration of cold exposure (χ² = 19.32, df = 3, P < 0.001). Male adults generally lived longer than female adults (immature stage: χ²=﹣3.88, P < 0.001; adult stage: χ² =﹣5.72, P < 0.001). The adult pre-oviposition period was prolonged by increasing the duration of cold exposure (immature stage: χ² = 14.40, df = 3, P = 0.002; adult stage: χ²= 60.04, df = 2, P < 0.001). With the exception of pupae exposed to cold for 96 h (40.9 eggs/female), the average female fecundity in other treatment groups did not significantly decrease compared to the control group (87.3 eggs/female). [Conclusion]  Exposing the pupae of P. xylostella to 8 ℃ had a greater impact on subsequent survival and oviposition than exposing fourth larval instar. The reduction in survival and reproduction increased with the duration of exposure to low temperature.