烟田瓜果腐霉的分离鉴定及其拮抗木霉菌株的筛选

Identification of Pythium aphanidermatum isolated from tobacco field and the screening of Trichoderma spp. for antagonistic agent

采用诱捕法从烟田土壤中分离到1株腐霉(Pythium spp.),鉴定为瓜果腐霉(Pythium aphanidermatum).接种试验结果表明该菌对烟草、黄瓜、辣椒具有致病性.采用对峙培养试验测定木霉菌(Trichodermaspp.)对瓜果腐霉的抑制作用,筛选出拮抗瓜果腐霉哈茨木霉(T.harzianum)菌株TGY040604,该菌株对瓜果腐霉的生长抑制率达到80%以上,其次生代谢产物对病原菌也具有一定的抑制效果.盆栽试验结果表明,该木霉菌菌株对烟草猝倒病的防效达65%,优于甲霜灵锰锌.

A strain of Pythium spp. was isolated from the soil of tobacco field, and was identified as Pythium aphanidermatum. Inoculation experiment results indicated that Pythium aphanidermatum could infect tobacco, cucumber and pepper. An excellent Trichoderma harzianum isolate TGY040604 was screened based on their inhibitory activities against Pythium aphanidermatum through dual-culture experiment, the inhibitory effect of TGY040604 on the growth rates of P. aphanidermatum reached 80%, and the secondary metabolites of Trichoderma spp. also had inhibitory effect on P. aphanidermatum. The pot experiment results showed the control effect of TGY040604 on tobacco damping-off reached 65%, and was better than metalaxyl-mancozeb.