Monitoring and management of the Nearctic leafhopper Scaphoideus titanus (Hemiptera: Cicadellidae) in Italian vineyards.

Abstract

The Nearctic leafhopper Scaphoideus titanus Ball (Hemiptera: Cicadellidae) is the main vector of the grapevine flavescence dorée (FD) phytoplasmas in Europe. To limit the impact of pest control activities on human health and the environment, EU legislation is withdrawing a growing number of active ingredients (a.i.), highlighting the need to evaluate alternative S. titanus management tools. In this context, we carried out a three-year (2021-2023) study in Italian vineyards characterized by high S. titanus populations. We compared the effectiveness of different insecticide-based strategies, i.e., targeting only nymphs (2021) or nymphs and adults (2022-2023), by spraying some of the currently allowed products (i.e., flupyradifurone, acetamiprid, sulfoxaflor, etofenprox, deltamethrin, and pyrethrins). The effectiveness of insecticide-based treatments was evaluated in terms of adult catches on yellow sticky traps. Furthermore, to achieve useful insights for optimizing current monitoring tools, we compared S. titanus catches on sticky traps of five different colors (i.e., yellow, green, blue, black, and white), as well as those achieved with two types of currently marketed yellow sticky traps. Results showed that etofenprox, deltamethrin, and sulfoxaflor were the most effective products for reducing S. titanus adult populations (33.64%, 30.30%, and 31.26%, respectively). Yellow and green sticky traps were more attractive to S. titanus adults than white, blue, and black ones. Moreover, a significant difference in capture efficiency was observed between two commercial yellow devices (i.e., tenfold higher catches using Glutor over Super color). Practical implications of our results are discussed in the context of current IPM against this key leafhopper vector of FD.