Towards a preventive and/or curative treatment of esca in grapevine trunk disease: General basis in the elaboration of treatments to control plant pathogen attacks

Wood degrading diseases are escalating in vineyards all over the world, inducing heavy economic losses. The diseases are caused by fungal pathogens that invade the innermost xylem part of the trunk and trigger many metabolic disorders of vines leading to hindered productivity. In particular, esca disease in which Phaemoniella chiamydospora and Phaeacremonium minimum are implicated, is very frequently observed. The aim of this work was to establish the basis of a preventive/curative treatment to control these types of diseases, since no efficient treatment is yet available. Therefore, we proposed to design a treatment based on a combination of active chemicals that exhibit antimicrobial properties per se and/or are able to activate the defense reactions of the plant. An essential property of the chemicals should reside in their capacity to be transported to remote areas within the plant. To this end, the chemicals chosen in our experimental model were cysteine, iron sulfate, salicylic acid and fosetyl aluminium. The effective conditions of application were determined and the efficiency of the treatments was verified on cuttings using an immunological assay. The non-toxicity of the treatments was tested on cuttings and vinestocks following a series of sprayings on leaves at various periods of the vine culture process.