合欢内生菌发酵物与农药复配防治黄瓜枯萎病的协同作用

Synergistic effect of Bacillus vallismortis mixed with pyraclostrobine on cucumber Fusarium wilt control

以合欢内生细菌H8(Bacillus vallismortis)为生防资源菌,制备其发酵产物,采用菌丝生长速率法测定并比较H8发酵物及3种常用杀菌剂福美双、多菌灵、吡唑醚菌酯对黄瓜枯萎病菌(Fusarium oxysporum)的室内毒力;选择毒力较高(EC_(50)为1.55μg/mL)的吡唑醚菌酯与H8发酵物进行不同比例的复配,测定各复配组合的毒力,筛选最优的增效配比;在此基础上开展盆栽试验,调查增效组合对黄瓜枯萎病的防治效果及对黄瓜生长的影响。结果表明,发酵物与吡唑醚菌酯的最佳混配比为6∶4,该配比下的组合对盆栽黄瓜枯萎病的防效达到87.53%,略高于吡唑醚菌酯单剂,显著高于其他药剂处理,并能有效促进黄瓜幼苗生长。

In this experiment,the ferment filtrate of Bacillus vallismortis H8,an endophyte isolated from the plant Albizia julibrissin,was tested as a biocontrol agent for controlling Fusarium wilt disease of cucumber.The toxicity of H8 ferment filtrate and three commonly used fungicides,namely thiram,carbendazim,and pyraclostrobin,against Fusarium oxysporum was determined using the mycelial growth rate method.Pyraclostrobin with high toxicity(EC_(50) of 1.55μg/mL)was selected to be mixed with H8 ferment filtrate in different proportions.The toxicity of each formula was determined,and the optimal ratio that delivered the highest synergistic effect was screened.In addition,a pot experiment was carried out to investigate the effect of the formulas on both cucumber fusarium wilt control and cucumber plant growth.The optimum mixing ratio of the H8 ferment filtrate to pyraclostrobin was 6∶4.With this formula,a control efficacy of 87.53%was achieved against cucumber Fusarium wilt in potted plants,which was slightly higher than that of the pyraclostrobin treatment and significantly higher than that of the other treatments.Furthermore,this mixture could effectively promote the growth of cucumber seedlings.