Susceptibility of cold hardy grapes to Drosophila suzukii (Diptera: Drosophilidae)

Abstract

Drosophila suzukii (Diptera: Drosophilidae), known commonly as spotted wing drosophila, is a vinegar fly originating from South‐East Asia and a major pest to many soft‐skinned fruits. Due to the species recent arrival in North America in 2008, many fruit varieties are yet untested for susceptibility to infestation. While previous work has focused on Vitis vinifera, this study aimed to determine grape susceptibility of cold hardy varieties based on hybrids of V. labrusca, V. riparia and V. vinifera. Field sampling was conducted in Southern Wisconsin (USA) vineyards to establish adult and larval abundance and determine whether the number of adults caught in traps correlates with fruit infestation. Host susceptibility was further assessed through no‐choice bioassays of both intact and damaged fruits. The field study found D. suzukii adults present in all varieties, low larval abundance and no correlation between adult abundance and larval presence. Peak adult abundance occurred mid‐season between veraison and harvest, while larval infestation rates were highest near harvest. In laboratory no‐choice tests, significantly more eggs, larvae and adults occurred in damaged than undamaged grapes. In damaged grapes, larvae and adult abundance was comparable between varieties and to the highly susceptible control of undamaged raspberry; however, D. suzukii developed significantly faster in raspberry than grapes. Fruit characteristics (°Brix, titratable acidity, pH) in grapes were uncorrelated with D. suzukii performance. Together, these findings suggest that cold hardy grapes are overall resistant to D. suzukii if intact and highly susceptible if damaged.

Effects of Variety and Grape Berry Condition of Vitis vinifera on Preference Behavior and Performance of Drosophila suzukii

“…Moreover, damage of berries from little accepted varieties turned these more susceptible. Importantly, we show that the pure presence of D. suzukii does not necessarily result in oviposition or successful offspring performance, which is in line with previous research on grapes [3,42] and in another fruit [12].…”

“…For example, sugar content has been previously described to be a relevant parameter for the development of D. suzukii [10]. Previous studies revealed that there is no correlation between oviposition or performance with measured sugar contents ( • Brix) [3,26]. In our study, only ripe berries of tested varieties were used for bioassays.…”

“…About ten years ago the Asian fruit fly Drosophila suzukii Matsumura (Diptera: Drosophilidae; spotted wing drosophila) was accidentally introduced into Europe and North America and nowadays it is a well-established economic pest across both continents [1][2][3]. A broad range of cultivated and wild soft-skinned fruit species have been identified as potential suitable hosts for this polyphagous generalist so far [4][5][6][7][8][9].…”

“…Moreover, there have been few studies reporting that previously injured berries are preferred by D. suzukii for oviposition compared to intact berries, which does not necessarily lead to a better performance of the offspring in those berries compared to that in intact fruit [34][35][36][37]. For example, in cold-hardy grapes and muscadine grapes, D. suzukii laid more eggs and had a better offspring performance in damaged compared to intact fruits [3,37]. Holle et al (2017) [36] found a higher infestation in injured blueberries, cherry tomatoes, and table grapes than in intact fruit, whereas adult emergence was only higher in injured grapes and tomatoes.…”

Management strategies against Drosophila suzukii: insights into Swiss grape growers choices

“…Susceptibility to infestation is also variety specific and depends mainly on skin hardness, sugar content and acidity levels . Grapes prone to damage might be more sensitive to D. suzukii than intact grapes, in some cases red grapes are reported to be more attractive than white varieties and the sensitivity of the grapes is higher when fully ripened…”