Trapping Is Not Effective for Limiting Damage by Vespa Velutina in Vineyards

Abstract

[Abstract] BACKGROUND: Vespa velutina is an invasive hornet that harms biodiversity, human health and agricultural products such as grapes. The use of baited traps is a popular method among producers to counteract its impact. However, their efficiency in agricultural settings has not been tested systematically. We investigated whether the use of traps is an effective method to reduce damage in vineyards, as well as the influence of trap and vineyard characteristics on the captures of V. velutina and nontarget insects in two areas of Galicia, NW Spain. RESULTS: We observed significant differences in bunch damage by V. velutina among and within areas, but unrelated to grape sugar content. We found no evidence of any positive effect of trapping in reducing damage, even if the density of traps is doubled or tripled. Commercial traps capture higher numbers of V. velutina and by-catch than homemade traps. Captures of V. velutina peaked in summer, and no significant differences were observed between areas or plots, whereas captures of by-catch were highly variable. CONCLUSION: The multifactorial nature of V. velutina damage in vineyards, and the high proportion and diversity of by-catch in traps make trap use unadvisable based on the present state of knowledge. Notwithstanding this, trapping before harvesting, when most damage happens, showed the highest selectivity and thus, was the least harmful trapping system to native entomofauna. More sustainable and effective methods of vineyard management and crop protection should be tested to guarantee the future of this productive sector in highly invaded areas.