The inhibitory effect of Epicoccum nigrum strain XF1 against Phytophthora infestans
2013
Li, Y. | Xia, L.Q. | Wang, Y.N. | Liu, X.Y. | Zhang, Ch. | Hu, T.L. | Cao, K.Q.
In this study the mechanisms of antagonism and biological control of Epicoccum nigrum strain XF1 on Phytophthora infestans were evaluated in vitro and in vivo. The dual culture test showed that the mycelial growth of P. infestans was inhibited by XF1 as the hyphae of P. infestans became stunted and distorted adjacent to the boundary of the XF1 colony, and the protoplasm of P. infestans mycelia was degenerated in the inhibition zone. Direct inhibition of sporangia and cystospore germination of P. infestans occurred on rye agar-covered slides where XF1 had grown. Sterile culture filtrates of XF1 inhibited zoospores release from sporangia and cystospore germination as well as germ-tube elongation of P. infestans. Application of a conidial suspension of XF1 (1.0×107 conidia mL−1) to a potato leaf 1h before inoculation with P. infestans provided the same level of control as 0.2% Kocide DF. Under greenhouse conditions, with a greater interval between the application of a conidial suspension of XF1 and inoculation with P. infestans the efficacy decreased. When the interval was 1 h, disease control efficacy was 89%; when the interval increased to 96h, the efficacy reduced to 66%. Under field conditions the increased interval between the applications of a conidial suspension of XF1 and P. infestans more drastically decreased control efficacy compared to that under greenhouse conditions. The efficacy decreased from 78% (1h interval) to 13% (96h interval). These results suggest that strain XF1 may be a potential biological control agent for potato late blight.
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