Kromann Peter, Taipe Arturo, Perez Willmer G, Forbes Gregory A
Department of Plant Biology, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, Dk-1871 Frederiksberg C, Denmark, and International Potato Center (CIP), P.O. Box 17-21-1977, Quito, Ecuador.
CIP, Quito, Ecuador.
Plant Dis. 2009 Feb;93(2):142-148. doi: 10.1094/PDIS-93-2-0142.
Accumulated rainfall thresholds were studied in seven field experiments conducted in Ecuador and Peru for their value in timing applications of fungicide to control potato late blight, caused by Phytophthora infestans. Fungicide regimes based on accumulated rainfall thresholds ranging from 10 to 70 mm were compared with calendar spray schemes of every 5 or 7 days. Very low thresholds of 10 to 20 mm gave similar levels of control and resulted in similar number of sprays as did calendar spraying. However, neither low thresholds nor calendar sprays were effective in protecting susceptible potato genotypes in over half of the experiments. Thresholds of 25 to 50 mm of rainfall led to reduction in the number of sprays needed to protect resistant cultivars but also resulted in high levels of disease on susceptible cultivars. We conclude that timing fungicide sprays based on accumulated rainfall thresholds could be a successful component of integrated management strategies that include cultivars with moderate or high levels of resistance. The simplicity of measuring accumulated rainfall means that the technology can potentially be used by resource-poor farmers in developing countries.
在厄瓜多尔和秘鲁进行的七项田间试验中，研究了累积降雨量阈值对于确定杀菌剂施药时间以控制由致病疫霉引起的马铃薯晚疫病的价值。将基于10至70毫米累积降雨量阈值的杀菌剂施药方案与每5天或7天的定期喷雾方案进行了比较。10至20毫米的极低阈值能提供相似的防治水平，且施药次数与定期喷雾相似。然而，在超过半数的试验中，低阈值施药和定期喷雾在保护易感马铃薯基因型方面均无效。25至50毫米的降雨量阈值可减少保护抗性品种所需的喷雾次数，但易感品种的病害发生率仍很高。我们得出结论，基于累积降雨量阈值来确定杀菌剂喷雾时间，可能是综合管理策略的一个成功组成部分，该策略包括具有中等或高抗性水平的品种。测量累积降雨量的方法简单，这意味着该技术有可能被发展中国家资源匮乏的农民所采用。
