Drosophila suzukii population dynamics in vineyards and wine cultivars susceptibility

Grapes are not considered a good host for the spotted-wing drosophila, Drosophila suzukii. However, its damage results in qualitative and quantitative losses to the wine grapes berries. Knowing the D. suzukii population dynamics in vineyards and surrounding areas, as well as the wine cultivars susceptibility, can help winegrowers to carry out the management. The objective of this study was evaluate the D. suzukii population dynamics in the field, on the forest border present around the vineyard and in its interior and evaluate the susceptibility of the main wine cultivars for Sao Joaquim municipality to the attack of D. suzukii in laboratory. In the vineyard, D. suzukii was monitored from November 2018 to May 2021 with weekly inspections. Plastic pot traps with a red stripe baited with the Droskidrink attractant were used, distributed among the vines and around the vineyard. Monitoring data were correlated with regional climate variables. In laboratory, through non choice and free-choice test, the susceptibility to D. suzukii damage was evaluated in Chardonnay, Sauvignon Blanc, Sangiovese, Cabernet Franc, Cabernet Sauvignon and Merlot berries. Intact and artificially injured berries were offered to adults in plastic screened cages for 24h. Afterwards, the number of punctures, eggs, emerged adults and the period of egg-adult development were evaluated. The data were analyzed in the R environment. Through monitoring, it was found that the presence of D. suzukii adults was higher in the forest border (762) in the surroundings compared to inside of the vineyard (128). The precipitation reduced the population of D. suzukii inside the vineyard, while the average and maximum temperatures promoted an increase in the population. In free choice tests, the cultivar Sangiovese was susceptible to the attack and development of D. suzukii. The cultivar Cabernet Sauvignon showed reduced egg-adult development time compared to the other tested cultivars in no-choice test.