Kaolin in vineyards: Effects on the leafhopper Erasmoneura vulnerata and non-target species such as predatory mites and egg parasitoids

Abstract

Recently, Erasmoneura vulnerata, firstly reported in Italy, has emerged in other European viticulture areas, indicating a potential spread of its associated issues across Europe. The most effective control strategies against E. vulnerata are those based on chemical insecticides, which can negatively impact non-target species. Organic control strategies mostly rely on pyrethrum, but its effectiveness seems limited, given the outbreaks in organic managed vineyards in North-eastern Italy. The control of E. vulnerata in organic farms must therefore be improved. In this study large scale trials were planned in several organically managed vineyards located in North-eastern Italy. We evaluated kaolin's impact on E. vulnerata and the effect on beneficial arthropods, particularly Acari Phytoseiidae and the egg parasitoids Hymenoptera Mymaridae. A decline in the leafhopper nymph population was observed in three out of four vineyards, while adults in two out of four. Kaolin affected predatory mite populations, but not permanently, and did not affect mymarid parasitism rates.