The economic impact of invasive pest Drosophila suzukii on berry production in the Province of Trento, Italy

BACKGROUND: The fly Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is an endemic pest, native to Southern Asia which has recently invaded western countries. Since its detection in 2008 in California and Spain, it is now established in North America and in many European countries. OBJECTIVE: This paper aims to evaluate the pest's economic impact on the soft fruit industry in the Province of Trento, a region in the North East of Italy, which is one of the most productive soft fruit areas in Europe. METHODS: The evaluation takes into account both the growers' potential revenue losses and the costs of pest control and uses a partial budgeting approach. Two scenarios are evaluated: the one before and the one after the implementation of an integrated control strategy for D. suzukii. RESULTS: Before the adoption of an integrated pest control strategy, the estimated revenue losses amounted to about 13% of the industry's output. After the implementation of an integrated strategy this loss decreased to about 7% of the industry's output. CONCLUSIONS: The adopted strategy seems effective in mitigating the pest's economic impact. The knowledge about D. suzukii's impact and its management would benefit from further analysis encompassing a larger geographical scope and longer time series.