河南省油菜菌核病菌对氯氟联苯吡菌胺及其复配剂的敏感性

Sensitivity of Sclerotinia sclerotiorum to bixafen and its mixtures in Henan Province

由核盘菌Sclerotinia sclerotiorum引起的菌核病(sclerotinia stem rot)是一种破坏性严重的病害,多发于油菜和许多其他阔叶作物,在农业生产中主要采用杀菌剂进行化学防治。氯氟联苯吡菌胺作为一种琥珀酸脱氢酶抑制剂(SDHIs),对核盘菌的菌丝生长有较好的抑制作用。为建立河南省核盘菌对氯氟联苯吡菌胺的敏感性基线,采用菌丝生长速率法测定了2015年和2016年从河南省不同地区采集分离的119株核盘菌对氯氟联苯吡菌胺的敏感性。结果表明:氯氟联苯吡菌胺对核盘菌菌丝生长的有效抑制中浓度(EC_(50))值范围为0.0417~0.4732μg/mL,平均EC_(50)值为(0.1968±0.1053)μg/mL。EC_(50)值频率分布范围窄且呈单峰曲线,平均EC_(50)值可以作为河南省核盘菌对氯氟联苯吡菌胺的敏感性基线。为明确氯氟联苯吡菌胺是否能与其他不同作用机制杀菌剂复配,采用菌丝生长速率法测定了核盘菌对氯氟联苯吡菌胺、多菌灵、咯菌腈、丙硫菌唑、菌核净、叶菌唑及其混合物的敏感性。结果表明,氯氟联苯吡菌胺、多菌灵、咯菌腈、丙硫菌唑、菌核净和叶菌唑对核盘菌EC_(50)值分别为0.1256、0.1122、0.0229、0.0651、0.8057和0.0278μg/mL。氯氟联苯吡菌胺与多菌灵、咯菌腈、丙硫菌唑、菌核净、叶菌唑(体积比1:1、1:3、1:5、3:1和5:1)复配剂的增效系数(SR)值范围为0.54~3.57,表现为相加或增效作用。综上结果表明,氯氟联苯吡菌胺可以与多菌灵、咯菌腈、丙硫菌唑、菌核净、叶菌唑这5种不同类型的杀菌剂通过交替或复配使用,阻止和延缓核盘菌抗药性的进一步发展。研究结果可为油菜菌核病的防治和河南省油菜菌核病菌对氯氟联苯吡菌胺的敏感性监测提供科学依据。

Sclerotinia stem rot is a destructive disease caused by the fungus Sclerotinia sclerotiorum,and it occurs in oilseed rape and many other broadleaf crops.The chemical control with fungicides is usually applied in fields.As a kind of succinate dehydrogenase inhibitors(SDHIs),bixafen showed higher efficiency in inhibiting mycelial growth.To establish the baseline sensitivity of S.sclerotiorum to bixafen in Henan Province,119 isolates of S.sclerotiorum were obtained from diseased stems of oilseed rape collected from fields in different geographical regions in Henan Province,China,in 2015 and 2016,and their sensitivity to bixafen was determined based on mycelial growth rate method.The results showed that the 50%inhibition of mycelial growth(EC_(50))values of S.sclerotiorum ranged from 0.0417 to 0.4732μg/mL with an average EC_(50) value(mean±SD)of(0.1968±0.1053)μg/mL.The frequency distribution range curve was narrow and unimodal,and the average EC_(50) value obtained can be used as the baseline sensitivity of S.sclerotiorum to bixafen in Henan Province.In order to determine whether bixafen can be mixed with other fungicides with different modes of action,the EC_(50) values of S.sclerotiorum to bixafen,carbendazim,fludioxonil,prothioconazole,dimetachlone,metconazole,and their mixtures were determined based on mycelial growth rate method.The results showed that the EC_(50) values for bixafen,carbendazim,fludioxonil,prothioconazole,dimetachlone and metconazole were 0.1256,0.1122,0.0229,0.0651,0.8057,and 0.0278μg/mL,respectively.For fungicide mixtures of bixafen and carbendazim,fludioxonil,prothioconazole,dimetachlone or metconazole(1:1,1:3,1:5,3:1 and 5:1,V/V),the synergistic ratio(SR)ranges from 0.54 to 3.57,which indicates additive or synergistic inhibition.These results suggested that bixafen could be used alternately or in combination with carbendazim,fludioxonil,prothioconazole,dimetachlone and metconazole to prevent and delay the development of resistance in S.sclerotiorum.These results provide important and scientific information for the control of sclerotinia stem rot and for monitoring the sensitivity of S.sclerotiorum to bixafen in Henan Province.