己唑醇及其复配剂对河南省禾谷镰孢菌的抑制活性及对小麦赤霉病的室内防效

Inhibitory activity of hexaconazole and its mixtures against Fusarium graminearum in Henan Province and its indoor control efficacy against Fusarium head blight

禾谷镰孢菌Fusarium graminearum是河南省小麦赤霉病的优势致病菌。为明确己唑醇对禾谷镰孢菌的抑制活性,测定了己唑醇对禾谷镰孢菌不同发育阶段的毒力,并采用菌丝生长速率法测定了己唑醇对采自河南省6个地区的205株禾谷镰孢菌的抑制活性,最后采用胚芽鞘接种法测定了己唑醇对小麦赤霉病的室内防效。结果表明:己唑醇对禾谷镰孢菌不同发育阶段的抑制活性存在较大差异,EC_(50)值(μg/mL)从大到小依次为孢子萌发(22.5750)>分生孢子产量(2.1686)>芽管伸长(0.8922)>菌丝生长(0.3862)。己唑醇对205株禾谷镰孢菌的EC_(50)值在0.0345~0.9439μg/mL之间,平均EC_(50)值为(0.3578±0.1928)μg/mL;敏感性频率分布均呈连续单峰曲线,表明田间不存在对己唑醇敏感性下降的抗性亚群体。己唑醇与多菌灵、咯菌腈、氰烯菌酯、咪鲜胺及氟唑菌酰羟胺复配,表现出不同程度的相加或增效作用,增效系数(SR)范围在0.5042~3.7293之间。其中,己唑醇与氟唑菌酰羟胺按质量比1:5复配时,SR最大,为3.7293,实际EC_(50)值为0.0133μg/mL。室内防效测定结果显示,复配剂的防治效果显著高于单一药剂多菌灵、己唑醇和氟唑菌酰羟胺。己唑醇与氟唑菌酰羟胺按质量比1:5复配后在9μg/mL下,对小麦胚芽鞘的防效为93.93%。生产中可将己唑醇与氟唑菌酰羟胺或咯菌腈进行复配或轮换使用,以延缓田间抗药性的产生。该研究结果可为己唑醇的科学使用以及小麦赤霉病的综合防治提供理论依据与数据支持。

Fusarium graminearum is the dominant pathogen causing wheat Fusarium head blight(FHB)in Henan Province.To elucidate the inhibitory activity of hexaconazole against F.graminearum in Henan Province,this study determined the toxicity of hexaconazole on F.graminearum at different developmental stages and the inhibitory activity of hexaconazole against 205 F.graminearum strains collected from six regions in Henan Province was determined using the mycelial growth rate method.Finally,the coleoptiles of wheat inoculation were used to determine the indoor control efficacy of hexaconazole against FHB.The results indicated significant variations in inhibitory activity of hexaconazole against F.graminearum at different developmental stages,with EC_(50)/(μg/mL)values ranking as follows:spore germination(22.5750)>sporulation quantity(2.1686)>sprout tube elongation(0.8922)>smycelium growth(0.3862).The EC_(50) value of hexaconazole against 205 strains of F.graminearum ranged from 0.0345 to 0.9439μg/mL,with an average EC_(50) value of(0.3578±0.1928)μg/mL.The frequency distribution of sensitivity exhibited a continuous single-peak curve,suggesting the absence of subpopulations with reduced sensitivity to hexaconazole.The results of the combination toxicity between hexaconazole and carbendazim,fluoxazonil,phenamacril,prochloraz,and pydiflumetofen revealed various additive or synergistic effects.The synergy ratio(SR)ranged from 0.5042 to 3.7293,with the maximum value observed at a ratio of m(hexaconazole):m(pydiflumetofen)=1:5(SR=3.7293),yielding an actual EC_(50) value of 0.0133μg/mL.The results of indoor control efficacy showed that the combined fungicides exhibited significantly higher control efficacy compared to single fungicides,namely carbendazim,hexaconazole,and pydiflumetofen.The control efficacy of m(hexaconazole):m(pydiflumetofen)=1:5 on coleoptiles of wheat was 93.93%at a concentration of 9μg/mL.In practical applications,hexaconazole should be combined or rotated with fluoxazonil or pydiflumetofen to prevent or delay the development of field resistance.This study provides crucial theoretical and data support for the rational use of hexaconazole and comprehensive control of FHB.