In 1989, Prof. Pierre de Wit was appointed as chair of the Laboratory of Phytopathology. At that time molecular phytopathology was rapidly emerging as a new discipline. De Wit and co-workers developed the Cladosporium fulvum tomato interaction into a model system for exploring the interaction between a host and a pathogenic fungus. The cloning of the first fungal avirulence gene was a major breakthrough, which contributed to the fame of the quality research at the Laboratory of Phytopathology.