Met Office Hadley Centre, Exeter, United Kingdom.
Birmingham Institute of Forest Research, School of Geography, Earth and Environmental Sciences, Edgbaston, Birmingham, United Kingdom.
PLoS One. 2019 Aug 27;14(8):e0221057. doi: 10.1371/journal.pone.0221057. eCollection 2019.
Bemisia tabaci (the tobacco whitefly) is an important agricultural pest of global significance primarily because of its ability to transmit multiple damaging plant viruses. To date, UK outbreaks of the whitefly have been restricted to glasshouses and there are no records of the whitefly establishing outdoors during the summer. This is despite the fact that annual degree-day models (that estimate accumulated warmth over the year above the development threshold), indicate that B. tabaci has the thermal potential for multiple summer generations in the UK. A set of 49 climate indices calculated using the present day climate (1986-2015) were therefore compared between the UK and the south of France, where B. tabaci is able to establish outdoors, to identify the factors limiting its establishment. The number of cold days and nights in summer, as well as the time spent within the whitefly's optimum temperature range, were most significantly different between the two areas. These indices may impact the development of B. tabaci and offer an explanation for the absence of the whitefly outdoors in the UK during the summer. Further analyses undertaken with climate projections suggest that in a 2-4°C warmer world this pest could pose a risk to outdoor UK crops in July and August. A clear south-north gradient can be demonstrated for these indices. Linking any possible northwards spread of B. tabaci populations outdoors in France with changes in these indices could therefore provide an important indicator of any change in the risks of outdoor populations of this species developing in the UK. The effectiveness of climate indices in pest risk analysis is compellingly demonstrated, and it is recommended that in-depth comparisons of climatic indices between areas of pest presence and absence are conducted in other situations where forecasting the risks of pest establishment are complex and challenging.
烟粉虱（烟草粉虱）是一种具有全球重要意义的农业害虫，主要原因是它能够传播多种破坏性植物病毒。迄今为止，英国的烟粉虱疫情仅限于温室，没有记录表明烟粉虱在夏季能在户外定殖。尽管每年的度日模型（估计全年超过发育阈值的累积热量）表明，烟粉虱在英国有多个夏季世代的热潜力。因此，使用当前气候（1986-2015 年）计算的 49 个气候指数集在英国和法国南部之间进行了比较，法国南部烟粉虱能够在户外定殖，以确定限制其定殖的因素。夏季冷天数和夜晚数以及烟粉虱最适温度范围内的时间是两个地区差异最大的因素。这些指数可能会影响烟粉虱的发育，并为英国夏季户外没有烟粉虱提供解释。进一步对气候预测的分析表明，在 2-4°C 更温暖的世界中，这种害虫可能会对 7 月和 8 月英国户外作物构成威胁。可以清楚地证明这些指数存在南北梯度。将法国户外烟粉虱种群可能向北扩散与这些指数的变化联系起来，因此可以为英国该物种户外种群发展风险的任何变化提供重要指标。气候指数在害虫风险分析中的有效性令人信服，建议在其他预测害虫建立风险复杂和具有挑战性的情况下，在害虫存在和不存在地区之间进行气候指数的深入比较。
