Side Effects of Sulfur Dust on the European Grapevine Moth Lobesia botrana and the Predatory Mite Kampimodromus aberrans in Vineyards

SIMPLE SUMMARY: The European grapevine moth Lobesia botrana is the most important carpophagous pest in European vineyards. Synthetic insecticides are usually applied for moth control, but their impact on human health and environmental quality requires a reduction in their usage. The exploitation of the side effects of inorganic fungicides of natural origin repeatedly used during the growing season can contribute to achieve this goal. In this study, a possible effect on L. botrana infestation of sulfur dust applied to control powdery mildew is tested under laboratory and field conditions. Sulfur dust reduced egg laying by around 80% in both laboratory and field bioassays. In the laboratory, the product showed a slight contact toxicity on eggs and reduced larval settlement. A single field application of sulfur dust during L. botrana egg laying reduced larval infestation by approximately 40%. No adverse effects were observed on the predatory phytoseiid mite Kampimodromus aberrans. ABSTRACT: To reduce the impact of synthetic insecticides on human health and the environment, eco-friendly alternatives must be investigated. Knowledge of the side effects on pests and natural enemies of natural products applied to vineyards is very useful. Sulfur dust, which is used in vineyards to control powdery mildew, is investigated in laboratory and field bioassays for its effects on Lobesia botrana egg laying, egg hatching, and larval settlement. In field trials, the efficacy of sulfur dust against the two L. botrana carpophagous generations is compared with that of Bacillus thuringiensis and kaolin, and its side effects on the phytoseiid mite Kampimodromus aberrans are evaluated. In the bioassays, sulfur dust reduced female survival by 43%, egg laying by around 80%, egg hatching by 10%, and larval settlement by 55%. In field trials, sulfur dust caused a significant decrease in the number of L. botrana larval nests of both generations, even though the efficacy was lower than that of B. thuringiensis. No negative effects of sulfur dust on the predatory mite population density was observed. On the basis of these results, in the context of Integrated Pest Management strategies in vineyards, the activity of sulfur dust against L. botrana could be exploited by timing its application to the beginning of egg laying.