Cultural Characterization and Antagonistic Activity of Cladobotryum virescens against Some Phytopathogenic Fungi and Oomycetes

In this study, the characteristic growth of Cladobotryum virescens on nine culture media was analyzed. The growing behavior of this fungus was dependent on the culture medium. In vitro analysis showed that oat agar was better than other media tested with the highest conidia production. The antifungal activity against Fusarium chlamydosporum and Alternaria brassicicola was evaluated by the Dual Culture method. C. virescens displayed high activity against both pathogens acting through antibiosis and mycoparasitism. This effect was increased by a higher competitiveness of the strain for the substrate. Furthermore, the crude ethyl acetate extract of the culture broth was tested in vitro against Botrytis cinerea and Septoria tritici, as well as the hemibiotrophic oomycete Phytophthora infestans using a microtiter plate assay at different concentrations. The extract showed excellent inhibition even below 5 ppm. According to these results, we concluded that C. virescens can be considered as a potential biological control agent in agriculture. To the best of our knowledge, this is the first study to investigate C. virescens as a biocontrol agent for different diseases caused by five relevant pathogens that affect cereals and vegetables.