Forrer Hans-Rudolf, Vogelgsang Susanne, Musa Tomke
Agroscope, Reckenholzstrasse 191, 8046 Zurich, Switzerland.
J Fungi (Basel). 2017 Nov 24;3(4):65. doi: 10.3390/jof3040065.
Potato late blight (PLB) caused by (Pi) is the most harmful disease in potato production worldwide. In organic farming, copper is used despite its persistence in soil and toxicity to soil organisms. To replace copper, suspensions of powders from three promising botanicals, including bark of buckthorn (, FA), roots of medicinal rhubarb () and galls of the nutgall tree (), were tested in multi-year field experiments. The current study shows for the first time that botanicals could replace copper under field conditions and best PLB reduction on leaves was achieved with FA, reaching a level close to that of 2 to 3 kg copper per hectare and year. Better results than with copper were achieved with Phosfik (Ph), a phosphonate-based product. For both FA and Ph, the mode of action is based on induced resistance, for Ph also on direct fungicidal effects. A disadvantage of Ph is the accumulation of residues in potato tubers. Nevertheless, two to three applications with 2 to 3 L/ha of Ph would be feasible to not exceed a minimal risk level (MLR) of 20 mg/kg of phosphorous acid as proposed by the European Food Safety Authority. Due to an excellent environmental profile and a complex mode of action counteracting Pi resistance, phosphonate-based products would be most suitable for sustainable PLB management in integrated pest management (IPM) programmes.
由致病疫霉（Pi）引起的马铃薯晚疫病是全球马铃薯生产中危害最大的病害。在有机农业中，尽管铜在土壤中具有持久性且对土壤生物有毒性，但仍被使用。为了替代铜，在多年的田间试验中测试了三种有前景的植物提取物的悬浮粉末，包括沙棘树皮（FA）、药用大黄根和五倍子树的五倍子。当前的研究首次表明，在田间条件下植物提取物可以替代铜，其中FA对叶片晚疫病的防治效果最佳，达到了每年每公顷2至3千克铜的防治水平。基于膦酸盐的产品Phosfik（Ph）的防治效果优于铜。对于FA和Ph，其作用方式均基于诱导抗性，对于Ph还具有直接杀菌作用。Ph的一个缺点是会在马铃薯块茎中积累残留。然而，按照欧洲食品安全局提议的每千克亚磷酸20毫克的最低风险水平（MLR），每公顷使用2至3升Ph进行两到三次施药是可行的。由于其优异的环境特性和对抗Pi抗性的复杂作用方式，基于膦酸盐的产品最适合用于综合虫害管理（IPM）计划中的可持续晚疫病防治。
