Impact of UV-C irradiation on mite populations in vineyards of Northeastern Italy

Abstract: The European Union limits the use of copper largely used in organic viticulture to
control the diseases in organic vineyards (EU Reg. 1981/2018) aiming at avoiding the
accumulation of heavy metal on ground. One alternative strategy in the pest/disease
management can be to adopt the ultraviolet radiation, in particular UV-B and UV-C. In this
study, CREA researchers verify the possible residual effect of UV-C irradiation on acarofauna
in a vineyard of Northeastern Italy. In the 2021, some rows of Glera cultivar were treated with
UV-C irradiation to evaluate their effect on development of downy and powdery mildews.
Contemporaneously, leaf samples were regularly carried on estimating the effects of irradiations on presence/abundance of mites (tetranychids, tydeids and phytoseiids). No particular effect of UV-C radiation was detected on the populations of mites, both phytophagous and predatory. The use of UV-C radiation can be effectively considered to protect the grapevine from fungal pathogens in compliance with the presence of beneficials/predatory mites.