Side Effects of Kaolin and Bunch-Zone Leaf Removal on Generalist Predators in Vineyards

SIMPLE SUMMARY: Kaolin application and bunch-zone leaf removal are two cultural practices that contribute to the control of main pests in vineyards, such as leafhoppers and the European grapevine moth. In the context of Integrated Pest Management (IPM), a two-year study on the side effects of these practices on generalist predators was conducted in three vineyards of a grape-growing area in north-eastern Italy. This study provides the first data on the influence of kaolin and bunch-zone leaf removal on spiders and predatory insects occurring in vineyards. It was demonstrated that moderate use of kaolin has a negligible impact on generalist predatory arthropods in vineyards, while no negative effects were associated with bunch-zone leaf removal. Therefore, these practices were compatible with IPM strategies. ABSTRACT: In vineyards, kaolin application and bunch-zone leaf removal (LR) were effective in the control of leafhoppers and Lobesia botrana, but their side effects on generalist predators are still poorly understood. In north-eastern Italian vineyards, the impact of kaolin and LR on species and functional diversity of spiders, as well as the abundance of spiders and generalist predatory insects, was assessed in one vineyard for two consecutive years and in two vineyards for one year. The ecological indices of the spider community were never influenced by kaolin and only in one case were they influenced by LR. At the spider family level, kaolin reduced the abundance of Araneidae, Oxypidae and Salticidae, but only in single cases. In single cases, kaolin reduced the amount of Orius sp. anthocorids and increased that of Scymninae coccinellids, whereas LR increased the amount of Aeolothrips sp. The moderate use of kaolin and the application of LR had negligible and inconsistent impacts on generalist predatory arthropods in vineyards and were therefore, compatible with IPM strategies.