Potential of Cover Crops to Control Arthropod Pests in Organic Viticulture

Plant diversity has the potential to conserve beneficials and thereby naturally controlling arthropod pests. Beneficials’ activity can be increased by pollen-rich plant species. Here we aimed to develop innovative viticultural systems that naturally control arthropod pests, by increasing plant diversity within vineyards planting of selected cover crops. The experimental vineyards were set-up in Chablis (France), Piacenza (Italy), Murfatlar (Romania), Manče (Slovenia), Valencia (Spain) and Nyon (Switzerland). Each vineyard was divided in a traditional and innovative subplot and monitored in 2019 and 2020. The effect of cover crops on arthropods was assessed according to a common protocol using visual samplings and specific traps. Analysing the obtained data, there were no statistically significant differences in the abundance of sampled arthropod pests in the innovative and the traditional systems. Yet, two of five studied pest species tended to be less abundant in the innovative systems. Regarding arthropod beneficials, flying parasitoids and bees tended to benefit from the planting of cover crops in the innovative compared to the traditional systems. Alike, predators such as spiders and carabids were more abundant in vineyards with understorey vegetation. Overall, the arthropod biodiversity seems to benefit from the planting of cover crops but without necessarily favouring pest suppression.