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

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.