Pythium aphanidermatum Suppression by Antagonistic Action of Trichoderma longibrachiatum

Excessive use of pesticides represents a growing problem in agriculture sustainability and food safety. The use of antagonistic fungal interactions represents a promising approach to achieve reduced pesticide input. Beneficial saprotrophic fungi from the genus Trichoredma are able to express different mechanisms of antagonistic activity and effectively suppress plant pathogens. The aim of the present research was to investigate the potential use of the antagonistic effect of T. longibrachiatum 10/5 strain against the plant pathogen Pythium aphanidermatum. The antagonistic activity of T. longibrachiatum 10/5 strain against P. aphanidermatum was tested in vitro by dual culture test. A glasshouse trial was conducted with cucumber plants grown on commercial substrate. Ten plants per container were inoculated at the cotyledon growth stage with P. aphanidermatum mycelium. The experiment was conducted in five replications. The number of inoculated plants without symptoms per treatment was recorded. P. aphanidermatum expressed asymmetrical growth in the dual culture test, and the colony diameter was reduced by 77% in comparison to the control. Sterile liquid culture filtrate of T. longibrachiatum 10/5 showed 50% efficiency in the suppression of cucumber damping-off caused by P. aphanidermatum. Metabolites produced by T. longibrachiatum 10/5 showed a suppressive effect on P. aphanidermatum damping-off, which has a potential in application in sustainable agriculture.