Abstract: The present invention relates to a method for detecting the presence of a virulent strain of Venturia inaequalis in a sample. Said method is based on identifying specific markers associated with virulent strains of Venturia inaequalis. Said detection method has a plurality of advantageous applications, such as determining geographical areas where strains are virulent, enabling, in particular, evaluation of the benefit of planting an orchard in said area with varieties carrying the corresponding resistance gene, evaluation of whether fungicidal treatment in an orchard is necessary, thus avoiding systematic preventive treatment, or evaluation of the health quality of an apple plant comprising the resistance gene Rvi6.