Molecular genetic tools in recent years allowed the identification and detailed functional analysis of genes involved in the interplay of pathogenic fungi and their host plants. In the focus of interest today are genes involved in signaling events which accompany and control all stages in the infection and colonization processes. From the view point of developing chemical control strategies, specially the early events in the interaction (i.e. the surface-bound events) are of interest. Further milestones are genes controlling the different life styles of fungi (bio-/necrotroph) and genes involved in overcoming/suppressing the host's defense. In addition, "black box" approaches based on genomic data have provided sets of new genes obviously involved in the interaction, but where the details of function have yet to be worked out.