Molecular methods used directly on clinical material play an important role in the diagnosis and gray mould pathogen. Molecular diagnostic tests that allow timely and accurate detection of pathogen are already implemented in many laboratories. The intent of this review is that the reader will better understand the variety of technical approaches to the molecular genetic testing for the gray mould pathogen. The early molecular diagnosis of gray mould pathogen should significantly aid in the development of therapies tailored to this clinically and pathogenetically distinctive subgroup of bio-prevention. It is therefore particularly timely and appropriate to analyze these issues in detail, specially the extent to which molecular biology has revised traditional diagnostic criteria. The role of genetic testing in assessing prognosis and identifying high-risk subgroups and in defining basic disease mechanisms and pathophysiology is, however, largely beyond the scope of this scientific statement.