Yoshida Megumi, Nakajima Takashi, Arai Michiyoshi, Suzuki Fumihiko, Tomimura Kenta
Research Team for Fusarium Head Blight Control, National Agricultural Research Center for Kyushu Okinawa Region (KONARC), 2421 Suya, Koshi, Kumamoto 861-1192, Japan.
Plant Dis. 2008 Aug;92(8):1164-1170. doi: 10.1094/PDIS-92-8-1164.
Fungicide application is one measure available to reduce the risk of Fusarium head blight (FHB) and mycotoxin contamination in barley. The stage at or near anthesis, or at full head emergence, is generally thought to be optimal for fungicide application, regardless of cultivar. However, we have previously found that the most critical time for Fusarium graminearum infection and mycotoxin accumulation in barley differs among cultivars. Whereas chasmogamous (open-flowering) cultivars were most susceptible at anthesis, cleistogamous (closed-flowering) cultivars were considerably resistant at anthesis but became susceptible after 'spent' anther extrusion. Therefore, this study evaluated the effect of the timing of fungicide application on FHB and mycotoxin (deoxynivalenol and nivalenol) accumulation in cleistogamous barley. Thiophanate-methyl fungicide was applied at different developmental stages, from before anthesis to 30 days after anthesis (DAA), under artificial inoculation conditions in the field in which inoculum spores were provided throughout the testing period. As expected, the optimal timing for chemical control of FHB and mycotoxin accumulation was the time around the beginning of spent anther extrusion rather than at anthesis. Later application, as late as 30 DAA, was also effective in controlling mycotoxin accumulation, although it was not effective in controlling disease levels.
施用杀菌剂是降低大麦赤霉病（FHB）风险和霉菌毒素污染的一种可行措施。无论品种如何，通常认为在花期或接近花期，或在穗完全抽出时施用杀菌剂最为适宜。然而，我们之前发现，大麦中禾谷镰刀菌感染和霉菌毒素积累的最关键时期因品种而异。开花型（开放花）品种在花期最易感病，闭花型（闭合花）品种在花期相当抗病，但在花药“凋谢”挤出后变得易感病。因此，本研究评估了施用杀菌剂的时间对闭花型大麦中FHB和霉菌毒素（脱氧雪腐镰刀菌烯醇和雪腐镰刀菌烯醇）积累的影响。在田间人工接种条件下，在整个测试期间提供接种孢子，在从花期前到花后30天（DAA）的不同发育阶段施用甲基托布津杀菌剂。正如预期的那样，化学防治FHB和霉菌毒素积累的最佳时间是花药凋谢挤出开始前后，而不是花期。后期施用，最晚到花后30天，在控制霉菌毒素积累方面也有效，尽管在控制病害水平方面无效。
