Influence of landscape complexity and vineyard management on leafhoppers’ abundance in North-Italian vineyards

Abstract: Various species of leafhoppers can infest grapevine in Italy. Among these, Empoasca vitis, Zygina rhamni and Scaphoideus titanus are the most important in vineyards of North-eastern Italy. The role of landscape complexity and that of management practices are often matter of discussion for their impact on the abundance of both pests and natural enemies. The aim of this study was to investigate the effects of landscape complexity and vineyard management strategies on the abundance of the three leafhopper species. The leafhopper egg parasitism rate was also calculated. The study was performed in the Conegliano-Valdobbiadene DOCG area in the growing season of 2016. Empoasca vitis was more abundant in conventional than in organic vineyards in early season within complex landscapes, while late in the season in the organic vineyards in extremely simplified landscapes. Higher numbers of Z. rhamni were recorded in organic vineyards, especially in late summer and within complex landscapes. A higher leafhopper egg parasitism rate was detected in more complex landscapes, reminding that natural vegetation can harbour a higher presence of natural enemies. The presence of S. titanus was more abundant in organic vineyards within complex landscapes. Here we found that both the landscape complexity and the pest management practices influenced leafhoppers population densities.