禾谷镰孢菌对氟唑菌酰羟胺敏感性基线的建立及药剂田间防效

Sensitivity of Fusarium graminearum topydiflumetofen and its field efficacyon fusarium head blight

为明确琥珀酸脱氢酶抑制剂类新型吡啶酰胺杀菌剂氟唑菌酰羟胺在中国小麦赤霉病防治中的应用潜力,分别采用菌丝生长速率法和孢子萌发法,测定了氟唑菌酰羟胺对湖北省6个地区106株禾谷镰孢菌的室内毒力、田间防效及其与多菌灵和氰烯菌酯的交互抗性。结果显示：氟唑菌酰羟胺对106株禾谷镰孢菌菌丝生长的EC_（50）值为（0.018 0±0.209 0）mg/L,平均值为（0.072 8±0.025 9）mg/L;对分生孢子萌发的EC_（50）值为（0.052 7±0.473 2）mg/L,平均值为（0.176 0±0.059 6）mg/mL;且其EC_（50）值频率分布均呈单峰曲线,因此可分别将菌丝生长和孢子萌发的平均EC_（50）值作为禾谷镰孢菌对氟唑菌酰羟胺的敏感性基线。初步的交互抗性测定结果表明,抗多菌灵或氰烯菌酯的菌株对氟唑菌酰羟胺均未表现出抗性。田间试验显示,氟唑菌酰羟胺有效剂量200 g/hm^2处理的防效（超过90.0%）显著高于对照药剂氰烯菌酯600 g/hm^2的防效（78.0%）,与空白对照相比增产效果在127%～135%之间。经氟唑菌酰羟胺处理后,小麦籽粒中由禾谷镰孢菌产生的毒素脱氧雪腐镰刀菌烯醇（DON）的含量比空白对照降低了55.09%。研究表明,氟唑菌酰羟胺对禾谷镰孢菌呈现出较高的室内活性且田间防效优越,同时还能降低小麦籽粒中DON毒素的含量及提高小麦产量,因此可作为生产中防治小麦赤霉病的替代或后备药剂,同时也可考虑用作为禾谷镰孢菌对多菌灵抗性治理的替代药剂。

The fungicide pydiflumetofen 3-（difluoromethyl）-N-methyl-N-[1-methyl-2-（2,4,6-trichlorophenyl） ethyl]-1 H-pyrazole-4-carboxamide, is a novel succinate dehydrogenase inhibitor（SDHI）. In order to determine thepotential application of this novel fungicide for the control of wheat head blight in China, the baseline sensitivities of Fusarium graminearum to pydiflumetofen crossresistance analysis and the field trail were determined. Toxicities of the pydiflumetofen on mycelium growth, conidial germination of 106 strains form six regions in Hubei Province were determined, the cross-resistance between carbendazim and phenamacril fungicides and the control efficacy was evaluated. The EC_（50） value of pydiflumetofen against the mycelial growth of 106 strains of F.graminearum was 0.018 0-0.209 0 mg/mL and the average value was（0.072 8 ± 0.025 9） mg/mL. The EC_（50） value of pydiflumetofen against conidium germination was 0.052 7-0.473 2 mg/mL and the average value was（0.176 0 ± 0.059 6） mg/m L. The EC_（50） values distribution of 106 strains measured by mycelial growth assay or by conidium germination assay exhibited as a unimodal curve and could be used for detecting any sensitivity changes of F. graminearum to pydiflumetofen in the future. The results of cross-resistance analysis indicated that there was no positive or negative cross-resistance between pydiflumetofen and carbendazim or phenamacril. In field trials, pydiflumetofen at 200 g a.i./hm^2 provided 90% control efficacy which was significantly higher than that of phenamacril at 600 g a.i./hm^2 and significantly raised the plot yield by 127%-135%（P 0.05） compared with the untreated controls.In conclusion, pydiflumetofen had very high activity against F. graminearum in vitro and excellent efficacy for the control of fusarium head blight（FHB）. Therefore it could be used to manage carbendazim-resistant F. graminearum population in the field.