梨黑斑病菌抗药性检测及其对啶酰菌胺的敏感性基线

黑斑病是梨的主要病害之一,近年来不少地区反映多菌灵等传统常用杀菌剂对其防治效果已出现下降。作者从浙江、江苏和安徽3省分离了252株梨黑斑病菌Alternaria kikuchiana,采用菌丝生长速率法检测了其抗药性发生情况。结果发现:所检测的黑斑病菌群体(n=252)对苯并咪唑类杀菌剂多菌灵的抗性频率为57.1%,且全部为高水平抗性(HR);对二甲酰亚胺类杀菌剂异菌脲的抗性频率为46.8%,全部为低水平抗性(LR);对甾醇脱甲基抑制剂类杀菌剂苯醚甲环唑的抗性为低水平(LR)及中等水平(MR),抗性频率均为28.6%;表明梨黑斑病菌对常用杀菌剂已产生较为严重的抗性。供试252株梨黑斑病菌对琥珀酸脱氢酶抑制剂啶酰菌胺的EC50值分布在0.12~3.85μg/m L之间,平均EC50值为(1.21±0.12)μg/m L,且其分布呈近似正态的单峰曲线。研究表明,啶酰菌胺可作为潜在的梨黑斑病防治替代药剂,其平均EC50值(1.21±0.12)μg/m L可作为梨黑斑病菌对啶酰菌胺的敏感性基线。

Detection of resistance of Alternaria kikuchiana causing pear black spot to fungicides and baseline sensitivity of A.kikuchiana to boscalid

Black spot caused by Alternaria kikuchiana is one of the main diseases of pears in China. Decreased controlling efficacy of traditionally applied fungicides(carbendazim etc.) against the disease was reported recently in some regions. Resistance development of 252 isolates of A.kikuchiana collected from different regions of Zhejiang, Jiangsu and Anhui province to fungicides was investigated through the mycelial growth rate method. The results showed that the resistance frequency of A.kikuchiana population(n=252) to carbendazim(a benzimidazole fungicide) was 57.1% and all resistant isolates showed high-level resistance(HR). The resistance frequency to iprodione(a dicarboximide fungicide) was 46.8% and all resistant isolates showed low-level resistance(LR). The LR and moderate-level resistance(MR) frequency to difenoconazole(a sterol demethylation inhibitor fungicide) was 28.6% and 28.6%, respectively. The results indicated that A.kikuchiana had developed resistance to these traditionally applied fungicides in Zhejiang, Jiangsu and Anhui province. Further work was carried out to establish the baseline sensitivity of A.kikuchiana to boscalid, a succinate dehydrogenase inhibitor fungicide. The EC50 values of boscalid to the tested population(n=252) varied from 0.12 to 3.85 μg/mL(mean value 1.21±0.12 μg/mL) following a unimodal distribution, suggesting that boscalid could be used as a potential alternative fungicide to control pear black spot.