The sweetpotato whitefly Bemisia tabaci is a destructive pest on a wide variety of agricultural crops. Whiteflies are managed largely through the use of insecticides, but B. tabaci has developed tolerance or resistance to a broad range of active ingredients. Identifying events where insecticide applications could be delayed or eliminated may mitigate insecticide resistance. One such event is cold weather, which can decrease whitefly activity including dispersal and mating, or kill a substantial proportion of the whitefly population when temperatures fall below freezing. The objective of this research was to quantify the effects of exposure period to subfreezing temperatures on the mortality of adult whitefly. Results showed that whitefly mortality could be predicted through a non-linear function of a composite variable of temperature and exposure time (x). This model was applied retroactively to six seasons of field data collected in southwest Florida during the months of November through February. Based on observation and model output, significant drops in the whitefly population were mostly associated with two or more cold events – separated by no more than 7 days – with at least one of those events with x > 13. Moreover, the decrease was sustained for 4–6 weeks after the last event. The ability to predict decreases in the whitefly population in response to freeze events gives growers the opportunity to relax insecticide schedules, particularly in the spring cropping season, with high confidence that their crop is at low risk to whitefly damage.

甘薯粉虱Bemisia tabaci是一种对多种农作物具有破坏性的害虫。主要通过使用杀虫剂来管理粉虱，但烟粉虱对多种活性成分产生了耐受性或耐药性。确定可以延迟或取消杀虫剂应用的事件可能会减轻杀虫剂抗药性。一个这样的事件是寒冷的天气，它可以减少粉虱的活动，包括扩散和交配，或者当温度低于冰点时杀死相当一部分粉虱种群。本研究的目的是量化暴露于零度以下温度的时间对成年粉虱死亡率的影响。结果表明，可以通过温度和暴露时间的复合变量的非线性函数来预测粉虱死亡率 ( x). 该模型被追溯应用于 11 月至 2 月期间在佛罗里达州西南部收集的六个季节的现场数据。根据观察和模型输出，粉虱种群的显着下降主要与两次或更多次寒冷事件相关——相隔不超过 7 天——其中至少一次事件的 x > 13。此外，这种下降持续 了最后一次活动后 4-6 周。预测粉虱数量因冻结事件而减少的能力使种植者有机会放宽杀虫剂计划，特别是在春季种植季节，他们对他们的作物受粉虱危害的风险较低很有信心。