Abstract: A method called “BioMolChem”, based on a triple approach (biological, molecular and biochemical) enabled us to evaluate and compare the efficacy and the mode of action of potential elicitors. This method, developed under controlled conditions, was applied in natural conditions in the vineyard. Although stimulators of plant defences are effective and reproducible in laboratory conditions, this method appears in natura more difficult to control and usually leads to widely variable results. Attempts were made in the vineyard in 2011 on plots treated with elicitors to provide some answers regarding the development of these alternative or complementary strategies. Elicitation in the vineyard shows a high variability but nevertheless provides significant protection under strong disease pressure, although being less efficient than a fungicide.