Johnson Dennis A, Cummings Thomas F, Ghanem Rita Abi, Alldredge J Richard
Department of Plant Pathology, Washington State University, Pullman 99164-6430.
American University of Beirut, Beirut, Lebanon.
Plant Dis. 2009 Mar;93(3):272-280. doi: 10.1094/PDIS-93-3-0272.
The effects of cumulative solar irradiance and rainfall on incidence of potato late blight (caused by Phytophthora infestans) in the Columbia Basin of south-central Washington and north-central Oregon were investigated using meteorological data collected near Othello, WA from 1990 through 2007 and Prosser, WA from 1990 through 2006. An association between solar irradiance and seasonal differences in late blight epidemics has not been quantitatively determined. Incidence of late blight in the Columbia Basin significantly increased as cumulative solar irradiance decreased during 1 April to 31 July and 1 June to 31 July at both Othello and Prosser. Incidence of late blight also increased as number of rainy days increased during 1 April to 31 July at Othello and Prosser and from 1 June to 31 July at Prosser. Coefficients of determination for significant models on late bight incidence ranged from 0.28 to 0.43 for cumulative solar irradiance and 0.27 to 0.38 for number of rainy days. Late blight incidence significantly increased as day of the year for first occurrence of late blight decreased in the Columbia Basin. A multiple regression model that included cumulative solar irradiance from 1 June to 31 July at Prosser and day of year for first occurrence of late blight as independent variables accounted for 58% of the variation for late blight incidence (adjusted R = 0.58), and a model that included number of cloudy days without rain combined with number of rainy days accounted for 62% of the variation for late blight incidence. This is the first report demonstrating a quantitative association of solar irradiance and incidence of late blight in commercial potato fields.
利用1990年至2007年在华盛顿州奥赛罗附近以及1990年至2006年在华盛顿州普罗瑟收集的气象数据，研究了累积太阳辐照度和降雨量对华盛顿中南部和俄勒冈州中北部哥伦比亚盆地马铃薯晚疫病（由致病疫霉引起）发病率的影响。太阳辐照度与晚疫病流行季节差异之间的关联尚未得到定量确定。在奥赛罗和普罗瑟，4月1日至7月31日以及6月1日至7月31日期间，随着累积太阳辐照度的降低，哥伦比亚盆地晚疫病的发病率显著增加。在奥赛罗和普罗瑟，4月1日至7月31日期间，以及在普罗瑟6月1日至7月31日期间，随着雨天数的增加，晚疫病的发病率也有所上升。晚疫病发病率显著模型的决定系数，累积太阳辐照度为0.28至0.43，雨天数为0.27至0.38。在哥伦比亚盆地，随着晚疫病首次出现的一年中的日期减少，晚疫病发病率显著增加。一个多元回归模型，将普罗瑟6月1日至7月31日的累积太阳辐照度和晚疫病首次出现的一年中的日期作为自变量，解释了晚疫病发病率变化的58%（调整后R = 0.58），一个包括无雨阴天数量和雨天数的模型解释了晚疫病发病率变化的62%。这是第一份证明商业马铃薯田中太阳辐照度与晚疫病发病率存在定量关联的报告。
