Résumé
The use of pesticides in viticulture can affects natural enemies and thus the success of conservation biological control. Increasing plant diversity in agroecosystems could provide refuges and food resources for natural enemies. Although this hypothesis has been confirmed in several meta-analyses, less information exists on the effect of cover crops on Phytoseiidae mites – known to be efficient predators in vineyards. Most Phytoseiidae are generalist predators, feeding on prey or pollen, and strongly influenced by plant leaf characteristics. Some studies highlighted the positive impact of cover crops in vineyards on Phytoseiidae communities, but information on the effect of traits of these non-crop plants on Phytoseiidae communities is lacking. This study aims to characterize beneficial weeds for predatory mites in a Mediterranean vineyard using both a taxonomic and functional approach through the measurement of six functional traits related to habitat quality, food quantity and quality, for the nine most abundant plant species in cover crops. In 2023, four plants harbored a high abundance and diversity of Phytoseiidae mites. Sixteen Phytoseiidae species were retrieved, the most abundant being Typhlodromus recki and Phytoseius finitimus. Phytoseiidae density were (i) positively correlated to the mean pollen grain number produced by the plant and (ii) negatively correlated to trichomes density of the leaf veins. The next step is to investigate whether improving Phytoseiidae communities on cover crops has a direct positive effect on Phytoseiidae on vine and the associated natural regulation. Results of this study are assumed to provide advice to growers when establishing cover crops.