Interaction between Acremonium byssoides and Plasmopara viticola in Vitis vinifera

The endophytic fungus Acremonium byssoides was isolated from the leaves of grapevine cv. Regina Bianca to determine whether it could act as an antagonistic endophyte of the downy mildew agent Plasmopara viticola. The occurrence of this fungus was ascertained in 34 grapevines (cultivars Regina Bianca, Catarratto and Insolia) representing all the grapevine plants in an experimental vineyard located in Sicily and which had never been treated with any fungicides. The isolation frequency of the endophytic Acremonium strains was assessed in several plant organs by means of monthly samplings over a 2-year period. The endophyte was found in all the grapevines, with higher frequencies in the cv. Reg…