Yoshida Megumi, Nakajima Takashi, Tomimura Kenta, Suzuki Fumihiko, Arai Michiyoshi, Miyasaka Atsushi
NARO Kyushu Okinawa Agricultural Research Center (NARO/KARC), 2421 Suya, Koshi, Kumamoto 861-1192, Japan.
Plant Dis. 2012 Jun;96(6):845-851. doi: 10.1094/PDIS-10-11-0819.
Fungicide application to control Fusarium head blight (FHB) and accompanying mycotoxin contamination in wheat is generally performed at anthesis because wheat is most susceptible to FHB around this stage. In this study, we evaluated the effect of the timing of fungicide application on FHB and mycotoxin (deoxynivalenol and nivalenol) accumulation in wheat based on our previous finding that the late period of grain development (beyond 20 days after anthesis [DAA]) is important to determine the final toxin contamination level in wheat. Thiophanate-methyl fungicide was tested under artificial inoculation conditions in which moisture and inoculum spores were provided throughout the testing period. Eight treatments differing in application timing (anthesis, 10, 20, and 30 DAA) and in the number of applications (0 to 2) were tested for 2 years. The results indicated that fungicide application timing differentially affects FHB (disease) and mycotoxin concentration. Fungicide application at 20 DAA reduced mycotoxin concentration in matured grain without reducing FHB severity, whereas application at anthesis was crucial for reducing FHB. These results and our previous findings suggest that around 20 DAA (late milk stage) is a potentially critical timing for mycotoxin control in wheat.
为防治小麦赤霉病（FHB）及伴随的霉菌毒素污染而进行的杀菌剂施药通常在花期进行，因为小麦在此阶段对赤霉病最为敏感。在本研究中，基于我们之前的发现，即籽粒发育后期（开花后20天[DAA]之后）对于确定小麦最终的毒素污染水平很重要，我们评估了杀菌剂施药时间对小麦赤霉病及霉菌毒素（脱氧雪腐镰刀菌烯醇和雪腐镰刀菌烯醇）积累的影响。在人工接种条件下对甲基硫菌灵杀菌剂进行了测试，在整个测试期间提供了湿度和接种孢子。测试了施药时间（花期、10、20和30 DAA）和施药次数（0至2次）不同的8种处理，为期2年。结果表明，杀菌剂施药时间对赤霉病（病害）和霉菌毒素浓度有不同影响。在20 DAA施药可降低成熟籽粒中的霉菌毒素浓度，而不降低赤霉病严重程度，而在花期施药对于降低赤霉病至关重要。这些结果以及我们之前的发现表明，大约在20 DAA（乳熟后期）可能是控制小麦霉菌毒素的关键时期。
