The importance of Drosophila suzukii for grapevine production

Abstract: The spotted-wing drosophila, Drosophila suzukii, is a vinegar fly native to Asia that has recently been introduced to Europe. Unlike most other drosophilids, D. suzukii females lay their eggs thanks to their serrated ovipositor in healthy fruits. Besides berries and stone fruits, table and wine grapevine production might also be at risk, since the pests’ development in grapes has been reported. The economic importance of D. suzukii for grape production is, however, still unclear and debated. By an electronic questionnaire we assessed in the framework of Euphresco the threat that D. suzukii poses to European vineyards in 2012. We received 22 responses from 14 different vineyards that covered about 10% of Europe’s viticultural area. At eight locations the population of drosophilids consisted of an assemblage of D. suzukii and native species with D. suzukii nowhere dominating the community of drosophilids. Although D. suzukii was present, it did not cause any major damages to table and wine grapes in 2012. Its management was based on sanitation measures and winegrowers renounced almost completely from the use of insecticides. Most respondents scored the potential of D. suzukii as an important viticultural pest therefore as low to medium. This is in contrast with respondents’ assessment of the situation in other late-maturing crops such as raspberry, blackberry and blueberry. At present D. suzukii is therefore considered as a minor pest of table and wine grapes in Europe. Yet, time will tell if this first assessment of the general situation was accurate or if this new pest will nevertheless be able to cause occasionally major damages in grapevine production.