不同杀菌剂在麦穗中的消解动态及对小麦赤霉病防效评估

为探明不同杀菌剂对小麦赤霉病及籽粒DON的防效，分别检测6种杀菌剂对亚洲镰刀菌（F.asiaticum）的室内毒力，采用超高效液相色谱－串联质谱法（UPLC-MS/MS）分别检测、分析了6种杀菌剂施药1次和2次在麦穗中的消解动态及其对小麦赤霉病和籽粒DON的防效。结果表明，6种杀菌剂对亚洲镰刀菌菌丝生长抑制度表现为咪鲜胺>戊唑醇>氰烯菌酯>氟唑菌酰羟胺>吡唑醚菌酯>嘧菌酯。6种杀菌剂在麦穗中消解动态均符合一级动力学方程，50%咪鲜胺WP、430 g·L^-1戊唑醇SC、25%氰烯菌酯SC、200 g·L^-1氟唑菌酰羟胺SC、250 g·L^-1吡唑醚菌酯EC和250 g·L^-1嘧菌酯SC施药1次消解半衰期分别为2.081 5、3.094 4、2.365 7、3.026 8、3.209 0和3.136 4 d，施药2次消解半衰期分别为2.044 7、3.332 4、2.529 7、3.397 8、3.300 7和3.179 6 d。200 g·L^-1氟唑菌酰羟胺SC施药1次和2次病指防效分别为85.96%和94.88%，DON防效分别为81.43%和88.91%。430 g·L^-1戊唑醇SC、25%氰烯菌酯SC和50%咪鲜胺WP施药1次和2次病指防效分别为61.48%~73.62%和75.33%~86.15%，DON防效分别为53.88%~69.70%和60.09%~79.45%。250 g·L^-1吡唑醚菌酯EC和250 g·L^-1嘧菌酯SC施药1次病指防效分别为63.76%和50.47%，DON防效分别为41.03%和-28.95%；施药2次病指防效分别为79.51%和61.10%，DON防效分别为52.75%和-18.08%。综上所述，氟唑菌酰羟胺对赤霉病和籽粒DON防效最佳，而吡唑醚菌酯和嘧菌酯对小麦赤霉病和籽粒DON防效不突出，甚至增加毒素污染。

Analysis of Dynamic Degradation of Different Fungicides in Wheat Spikes and Their Control Efficacy on Fusarium Head Blight

In order to investigate the control efficacy of different fungicides on Fusarium head blight(FHB) and deoxynivalenol(DON) contamination in wheat grain, the indoor toxicity of six fungicides to F.asiaticum was detected in dividually,and the digestion dynamics of the six fungicides sprayed once and twice on wheat spikes were detected and analyzed by using ultra-performance liquid chromatography-tandem massspectrometry(UPLC-MS/MS)method. The field control tests of the six fungicides sprayed once and twice on FHB and DON contamination in wheat grain were conducted.The results showed that the degree of in hibition of the six fungicides on the mycelial growth of F.asiaticum were presented as follows:prochloraz>tebuconazole>phenamacril>pydiflumetofen>pyraclostrobin>azoxystrobin. The degradation dynamics of the six fungicidesin wheat spikes were conformed to the first-order kinetic equations.The half-lives of 50% prochloraz WP,430 g·L^-1 tebuconazole SC,25% phenamacril SC, 200 g·L^-1 pydiflumetofen SC, 250 g·L^-1 pyraclostrobin EC and 250 g·L^-1 azoxystrobin SC sprayed once on wheat spikes were 2.081 5, 3.094 4, 2.365 7, 3.026 8, 3.209 0 and 3.136 4 days, respectively,and 2.044 7, 3.332 4, 2.529 7, 3.397 8, 3.300 7 and 3.179 6 days under twice spray, respectively. The results of field trials showed that the FHB disease index(DI) control efficacy of 200 g·L^-1 pydiflumetofen SC sprayed once and twice were 85.96% and 94.88%, and the DON control efficacy were 81.43%and 88.91%,respectively.The DI control efficacy of 430 g·L^-1 tebuconazole SC, 25% phenamacril SC and 50% prochloraz WP sprayed once and twice were 61.48%-73.62% and 75.33%-86.15%,and the DON control efficacy were 53.88%-69.70% and 60.09%-79.45%,respectively.The DI control efficacy of 250 g·L^-1 pyraclostrobin EC and 250 g·L^-1 azoxystrobin SC sprayed once were 63.76% and 50.47%, and the DON control efficacy were 41.03% and -28.95%,respectively.The DI control efficacy of 250 g·L^-1pyraclostrobin EC and 250 g·L^-1 azoxystrobin SC sprayed twice were 79.51% and 61.10%, and the DON control efficacy were 52.75% and -18.08%,respectively.Pydiflumetofen provided best control efficacy on FHB and DON contamination in wheat grain among different fungicides. However, pyraclostrobin and azoxystrobin provided weak control efficacy on FHB and DON contamination in wheat grain, and even increased DON contamination. This study provides a scientific basis for the chemical control of FHB and DON contamination in wheat grain.