嘧菌酯对河南省小麦茎基腐病菌的抑制活性及对病害的防治效果

Inhibitory activity of azoxystrobin against the pathogenic fungi of wheat crown rot in Henan Province and its control efficacy on the disease

主要由假禾谷镰孢Fusarium pseudograminearum引起的茎基腐病是小麦上的重要病害,对产量及质量都有严重影响,目前尚无登记应用在该病害防治上的化学药剂。本研究从河南省17个地市采集病害样本,分离纯化得到82株小麦茎基腐病菌菌株,包括76株假禾谷镰孢和6株禾谷镰孢。嘧菌酯抑制76株假禾谷镰孢孢子萌发的EC_(50)值为0.02~1.54μg/mL,平均EC_(50)值为(0.33±0.29)μg/mL;经数据异常值检验,舍弃异常菌株LHWY-6及SQYC-6后,嘧菌酯对74株(97.37%)正常菌株的平均EC_(50)值(0.30±0.24)μg/mL可作为假禾谷镰孢对嘧菌酯的敏感性基线;不同地市菌株间敏感性存在差异,同一地市菌株间对嘧菌酯的敏感性差异较大,许昌、焦作、洛阳和商丘4市的菌株间敏感性差异倍数均在20.00以上,南阳、三门峡和开封3地的菌株间差异倍数均在2.00以下,其他地市菌株间差异倍数在2.70~12.00之间;假禾谷镰孢孢子萌发对嘧菌酯与其对丙硫菌唑、多菌灵、咯菌腈、氰烯菌酯、吡唑醚菌酯和戊唑醇的敏感性相比,除吡唑醚菌酯外其余5种药剂的抑制作用均弱于嘧菌酯;嘧菌酯对6株禾谷镰孢的EC_(50)值在0.10~0.42μg/mL之间,平均EC_(50)值为(0.19±0.12)μg/mL;嘧菌酯对两种镰孢菌丝生长的抑制活性均较弱,EC_(50)都在7μg/mL以上。离体条件下,15%嘧菌酯悬浮种衣剂在260 g/(100 kg种子)剂量下防效达63.64%;温室盆栽时,在220 g/(100 kg种子)剂量下防效为55.24%。嘧菌酯对小麦茎基腐病菌孢子萌发有明显的抑制作用,且在离体和温室条件下对病害均有很好的防治效果,可作为备选药剂推广使用。

Wheat crown rot caused by Fusarium pseudograminearum is an important disease of wheat and leads to a severe impact on the yield and quality of wheat.At present,there are no chemical fungicides registered for the control of this disease.In this study,samples were collected from 17 cities in Henan Province and 82 strains of wheat crown rot were isolated and purified,including 76 strains of F.pseudograminearum and 6 strains of Fusarium graminearum.The EC_(50) values of azoxystrobin on spore germination of F.pseudograminearum 76 strains are 0.02-1.54μg/mL and the average EC_(50) value is(0.33±0.29)μg/mL.According to the test of abnormal data,LHWY-6 and SQYC-6 were the abnormal strains.The average EC_(50) values of azoxystrobin to 74 isolates(97.37%)was(0.30±0.24)μg/mL after discarding the two outliers,which could be used as the sensitivity baseline of F.pseudograminearum to azoxystrobin.The sensitivity of strain from different cities varies.The sensitivity to azoxystrobin is also fluctuant for the strains from the same city.The fold changes of strain sensitivity from Xuchang,Jiaozuo,Luoyang and Shangqiu are all above 20.00,that from Nanyang,Sanmenxia,and Kaifeng are all below 2.00,and from the other cities are between 2.70-12.00.When the sensitivity of F.pseudograminearum spore germination to azoxystrobin was compared with that to prothioconazole,carbendazim,fludioxonil,phenamacril,pyraclostrobin,and tebuconazole,the results showed that the inhibitory effects of 5 fungicides on spore germination are lower than those of azoxystrobin,except pyraclostrobin.The EC_(50) values of azoxystrobin against 6 strains of F.graminearum are 0.10-0.42μg/mL and the average EC_(50) value is(0.19±0.12)μg/mL.The inhibitory activity of azoxystrobin on the mycelial growth of the two species of Fusarium is faint with EC_(50) of above 7μg/mL.The 15%azoxystrobin FS agent has a 63.64%control effect against wheat crown rot with a dose of 260 g/(100 kg seeds)in vitro and a control effect of 55.24%with a dose of 220 g/(100 kg seeds)in the greenhouse.Azoxystrobin shows a notable inhibitory effect on spore germination of wheat crown rot fungi,has a good effect on disease control in vitro and greenhouse conditions and can be used as a high-quality alternative fungicide in the field.