The potential economic impact of Drosophila suzukii on small fruits production in Trentino (Italy).
Small fruits production is an important agricultural activity in Trentino, a mountain region in the North East of Italy. Between 2000 and 2010 cultivated areas almost doubled, while output increased from about 15 to more than 30 MEUR per year. Overall, this made soft fruits a viable alternative for local growers to the more traditional, and commercially-mature, apple production. This development was recently challenged by the emergence of Drosophila suzukii, first detected in the area in 2009. In order to provide a first estimate of the pest's economic impact, the five host crops mostly affected by the pest infestation (strawberry, raspberry, blueberry, blackberry and cherry) were singled out. Business data coming from the grading of infected samples at the level of marketing co-op were used. It was assumed that quantity reductions caused by infestation in Trentino do not affect market prices but, given that the damages vary during harvesting season, production losses were valued on a weekly basis with the corresponding weekly output.