Plants, parasites and pathologists: from understanding interaction to sustainable management of resistance

Plant resistance to pests and pathogens, which has been known for over a century to be a heritable - and hence selectable - trait, has been the topic of in-depth research over the past decades. Obvious progress has been made on the detailed knowledge of resistance genes and mechanisms (gene mapping and cloning, genetic transformation, marker-assisted breeding), as well as on a better deciphering of adaptive processes in pest and pathogen populations in response to the use of resistant hosts. Such work has hardly resulted, however, in the widespread adoption of resistant cultivars and/or in substantial increases of resistance durability. On the basis of a case study about potato late blight, this paper attempts to elucidate some of the reasons for this gap, and to offer hints with a view to better integration of available knowledge and an improved understanding of the actors' needs.