No abstract

Microbial bioprotectants and natural substances have been increasingly available and implemented for disease management in horticultural crops. This chapter presents the status of registered products and their current insufficiency to fulfill farmers’ needs for disease control solutions. It highlights possible advances to meet those needs, which include extending the spectrum of activity of existing products, finding new active substances, and facilitating registration of bioprotectants. It addresses issues on enhancing the field efficacy of bioprotectants on horticultural crops, through the expansion of knowledge on their modes of action, the Identification key factors of efficacy, the improvement of delivery and the complementation of bioprotectant use with other solutions from the IPM toolbox. It provides data on adoption of bioprotectants by horticulturists in France and reviews possible obstacles for wider adoption and proposes perpectives on ways to help farmers cope with the technical complexity of deployment.

Plant pathogens can develop resistance to conventional plant protection products but their ability to overcome the effect of microbial bioprotectants is still poorly known. However, various studies show that susceptibility of plant pathogens to microbial bioprotectants can be highly variable. This may contribute to the inconsistent efficacy of microbial bioprotectants sometimes observed in the field. An important question is whether the widespread use of microbial bioprotectants in the field could conduct to the selection of even more resistant phenotypes of plant pathogens. This chapter highlights current knowledge concerning erosion of microbial bioprotectants against plant pathogens and its possible consequences for field efficacy.