The use of cover plants in orchards requires assessment of their soil coverage rate, sustainability and impact on cash crop nitrogen nutrition and water supplies. In vegetable crop fields, when using trap plants for controlling flying insects, it is essential to take into account the spatiotemporal locations of the trap plant with respect to the main crop, whereas when sanitizing plants are used to control soilborne pathogens, it is necessary to assess their host status and effects on biological activity within the soil. Twenty plant species were assessed in controlled conditions and in a research station. In orchards, the initial results indicate that the requirements could be fulfilled by planting multispecies cover integrating several families. In vegetable crop fields, the results enabled assessment of periods of attractiveness of the tested trap plants and worm development on these plants. In parallel, five sanitizing plants were selected on the basis of their non-host status or low density host status without impact on the propagation of pathogen populations in the rhizoshere. These candidate species were chosen as plant models for testing direct impacts on pathogens and indirect impacts on other soilborne microbial communities.