大蒜紫斑病生防菌的筛选、鉴定及其田间应用

Screening,Identification and Control Efficacy of Biocontrol Strain against Purple Blotch of Garlic

大蒜紫斑病是江苏各产区大蒜生产中常见的病害之一,其造成巨大的经济损失。目前大蒜紫斑病的防治以化学防治为主,在生物防治研究方面则进展缓慢。为提高大蒜紫斑病生防水平,本研究通过筛选对大蒜紫斑病菌有拮抗作用的生防菌,从大蒜种植田土壤中分离得到了122株细菌菌株,其中对大蒜紫斑病菌有拮抗作用的菌株61株,进一步复筛得到12株拮抗能力较强菌株。依据形态学观察,并结合16S rRNA和rpoB基因序列分析,其中两株生防菌JS51和JS62鉴定为贝莱斯芽胞杆菌Bacillusvelezensis。盆栽试验和大田试验结果显示,菌株JS51和JS62对大蒜紫斑病有较好的防治效果,分别达到61.63%和55.05%,与化学药剂咪鲜胺锰盐的防效相当。

Purple blotch is one of the common diseases in various garlic-growing areas in Jiangsu,China.It causes huge economic losses and affects the sustainable development of the garlic industry.At present,the prevention of garlic purple blotch is mainly dependent on chemical control,while biological control research is limited.To improve the prevention level of garlic purple blotch,the biocontrol strains with clear antagonistic effect against garlic purple blotch pathogen(Alternaria alternata)were selected,and the control efficacy was evaluated with pot experiment and field trial.Among the 122 bacterial strains isolated from the soil of garlic fields,61 strains were antagonistic to A.alternata,and the 12 strains with the strongest antagonistic ability were analyzed in more detail.Pot experiment and field trial showed that the JS51 and JS62 had the highest control efficacy against garlic purple blotch,and their control efficacies reached 61.63%and 55.05%,respectively,which was equivalent to that of prochloraz-manganese chloride complex.Based on morphological observations and molecular analyses of 16S rRNA and rpoB gene,JS51 and JS62 strains was identified as Bacillus velezensis.These strains have the potential to be developed into environmentally friendly biological pesticides in the future.