NOTES ON DROSOPHILA SUZUKII MATSUMURA (DIPTERA DROSOPHILIDAE): FIELD SURVEY IN TUSCANY AND LABORATORY EVALUATION OF ORGANIC PRODUCTS

Reported for the first time in Italy in 2009, the Spotted Wing Drosophila (SWD), Drosophila suzukii (Matsumura) (Diptera Drosophilidae), has rapidly spread throughout the country, causing serious damage on many fruit crops. The potential of infestation rate by D. suzukii is enormous: the females can complete many generations per year, and are able to attack the fresh, ripe fruit of many hosts by laying eggs under the soft skin; the larvae grow in the fruits and destroy the commercial value of them. The host range of SWD is reportedly wide, including both cultivated (soft fruits, sweet cherry, stone fruits etc...) and wild plants. In 2013, field surveys aimed at monitoring the presence of the insect on Tuscany territory, were regularly carried out: on an important district for the sweet cherry production with differently managed in control, on a biological blueberry orchard and even on other host plants neighboring the samples' areas. D. suzukii was present in the monitored areas and its numerically large populations and heavy infestations on sweet cherries have shown that the species has settled in these areas. In laboratory tests, labeled organic products and substances of natural origin - in accordance with the requirements of EU regulations which provides for the reduction of chemicals - were evaluated as concern toxicity and residual effect on the pest. As regards effects of direct toxicity, products based on Beauveria bassiana have shown some effectiveness in the control of SWD, other organic products have shown interesting results. The evidences acquired are discussed.