IMPACT OF KAOLIN AND BEAUVERIA BASSIANA TREATMENTS AGAINST OLIVE FLY ON THE NON-TARGET ARTHROPODS OF THE OLIVE ECOSYSTEM

Abstract

The study of biodiversity has received a growing interest from the scientific community. Investigations of the efficacy of compounds allowed in organic farming and their risks for human and environmental health represent an increasingly large body of literature. The aim of this study was to evaluate the environmental impact of two compounds that have potential for registration as organic insect management tools against Bactrocera oleae. Kaolin clay, a repellent, and a micoinsecticide based on the vital spores of Beauveria bassiana were tested in an olive ecosystem. Selected arthropod taxa (Arachnida: Araneae and Opiliones; Hyrraenoptera: Ichneumonidae; other Hymenoptera; Coleoptera: Coccinellidae; Lepidoptera; Neuroptera; Mecoptera and Diptera: Syrphidae) were utilised as bioindicators. Arthropods were collected using yellow sticky traps. The ratio of pest: beneficial arthropods were used to evaluate the sustainability of the agroecosystem. The experimental olive grove was located in Southern Italy, in the middle of Mediterranean Basin. The abundance of Araneae and Hymenoptera was reduced by both treatments, while Lepidoptera were reduced only in the kaolin-treated plots. The ratio of pest: beneficial arthropods were unchanged after treatments. Results demonstrate that both tested products utilised against Bactrocera oleae showed few negative effects on beneficial arthropod populations. The taxon Araneae was identified as the best bioindicator, as these species were able to indicate well-preserved environmental conditions. More investigation on the efficacy of B. bassiana against the olive fly and on its impact on the above ground arthropods is required.