Seminatural habitats support both grapevine pests and their parasitoids in Mediterranean organic vineyards

Seminatural habitats in agroecosystems support diverse communities of natural enemies and are expected to promote biological control in crop fields. However, complex landscapes may also support agricultural pests, with undesirable outcomes for crop production. Here, we monitored populations of leafhopper pests and their egg parasitoids in two habitats: vineyards and seminatural habitats. Our results showed that the composition of the agricultural matrix strongly influences the spatio-temporal dynamics of leafhoppers and their egg parasitoids. Specifically, seminatural habitat cover in the landscape was positively correlated to leafhopper abundance in vineyards and to parasitoid abundance in both habitats. Vineyard cover in the landscape instead influenced leafhopper abundance in seminatural habitats. Our analyses indicate that seminatural habitats might be a greater source of leafhoppers than of their egg parasitoids in Mediterranean agroecosystems, with negative implication for their sustainable control in organic vineyards. Although seminatural habitats play a fundamental role in supporting farmland diversity and ecosystem service provision, they might not contribute to mitigate leafhopper impact in Mediterranean vineyards.