Vegetal residue‐based formulation of Trichoderma ossianense , a new indigenous vineyard species adapted to alkaline pH with potential biocontrol ability against Black‐foot disease pathogens

BACKGROUND Fungi of the Trichoderma genus are used in vineyards as biological control agents mainly against grapevine trunk diseases. The use of indigenous strains of this fungal genus favors their efficacy since they are optimally adapted to the environmental conditions. Some factors, such as the pH of soils colonized by Trichoderma , are essential to guarantee its efficacy against grapevine pathogens. For this reason, the aim of this study was to search for Trichoderma strains adapted to soils with alkaline pH, predominant in different wine‐growing areas of Spain, able to combat the pathogen Ilyonectria sp. , the causal agent of the grapevine black‐foot disease. RESULTS This study identified a new Trichoderma species, T. ossianense , isolated from grapevine roots. This isolate is able to grow in alkaline pH and shows efficacy in the biocontrol of pathogens of the Ilyonectria and Dactylonectria genera, which cause black‐foot disease in grapevine. Algae residue bioformulations of T. ossianense maintain spore viability at low temperatures during storage periods, whereas the wheat residue‐based formulation shows higher ability to supply nutrients and promote Trichoderma development under field conditions. CONCLUSION This study opens up a wide range of possibilities for the protection of vineyards in areas with alkaline pH, as well as for the prevention of Ilyonectria sp. and Dactylonectria sp. in nurseries and young vineyards using vegetal residue‐based formulations of T. ossianense . These results highlight T. ossianense as a reliable, safe, and promising biocontrol agent against grapevine Black‐foot disease.