Drosophila suzukii (Diptera: Drosophilidae): An exotic pest of small fruits in Cabernet Sauvignon vineyards of Santa Catarina State, Brazil

To characterize the annual Drosophila suzukii population dynamics in vineyards in Santa Catarina, Brazil, and to relate it to the local climatic conditions, we conducted a weekly monitoring survey in four commercial vineyards of Cabernet Sauvignon, between November 2018 and October 2020. The D. suzukii population was monitored both inside the vineyards and the surrounding forest border and correlated with climate variables. To capture the insects, plastic pot traps baited with the attractive Droskidrink were used. The traps were inspected weekly throughout two years, and the captured insects were counted and identified. The relationship between population fluctuations and climate variables was analyzed with multiple regression models. The numbers of D. suzukii captured in the forest borders were typically much higher than those into the vineyards, but in certain periods of the year, D. suzukii adults was indeed detected inside all vineyards. The number of captures varied between the years of monitoring, where the first year had higher numbers of adults captured for all monitored sites. The D. suzukii population numbers in all monitored vineyards were positively correlated with high relative humidity. The results show that there is indeed a significant risk of crop damage due to D. suzukii infestations in vineyards, but only during a distinct period during the ripening of the grapes. We recommend that farmers specifically perform D. suzukii management in their vineyards during this relatively short period of the year.