Effects of vineyard management and landscape composition on pest control by predatory mites across European wine growing regions

Abstract

Ecosystem services and biodiversity in vineyards are strongly influenced through local edaphoclimatic factors, viticultural practices and landscape composition. Pest control by natural enemies is an important ecosystem service for wine production, contributing to the EU goal to reduce pesticide use by 50 % until 2030. Important natural enemies in this context are predatory mites which are effective in controlling pest mites on vines. In this study, we investigated predatory and pest mite densities in 156 vineyards across five European wine-growing regions ranging from southern Spain to central Romania differing in respect to pesticide use, farming types, inter-row management and landscape composition. We hypothesized that (i) intensive viticultural management practices (e.g. high usage of pesticides and/or intensive vegetation management) would decrease predatory mite populations as well as species richness and that (ii) higher proportions of semi-natural habitats at the landscape scale may mitigate the negative effects of intensive management on predatory mites. Our results showed that only one or two predatory mite species dominated their community composition in the respective wine-growing regions. Furthermore, the farming type was one major factor for predatory mite densities. Conventional and integrated farming resulted in higher population densities compared to organic farming in the Austrian and French study region. The effect of the farming type could be linked to the beneficial impact of a lower pesticide use and lower toxicity for predatory mites in conventional and integrated vineyards. Predatory mite densities also benefited more from spontaneous vegetation cover compared to seeded cover crops in the vineyard inter-row. The increased predatory mite densities in the vineyards with spontaneous vegetation cover could be related to a better supply of pollen as food resource in this inter-row management type compared to seeded cover crops. Contrary to our expectations, predatory mite densities benefited through an increased proportion of vineyards in the surrounding landscape. Our findings showed accordingly, that predatory mites as natural enemies in European vineyards could be promoted through a reduced use of pesticides and extensive vegetation management in the inter-rows. This findings should be considered for European agri-environmental programmes in viticulture to increase natural pest control and at the same time to reduce harmful pesticide use, thereby contributing to the EU pesticide reductions goals.