Influence of Previous Fruit Injury on Susceptibility to Spotted Wing Drosophila (Diptera: Drosophilidae) Infestation in the Midwestern United States

Spotted wing drosophila, Drosophila suzukii (Matsumura), is a major agricultural pest throughout most of the fruit growing regions of the United States, with high reproductive rates and short generation times resulting in exponential population growth in berry crops across the country. Fruit suitability research has been conducted for some small fruit species such as raspberries, strawberries, cherries, and blackberries; however, there is a paucity of data regarding the role of previous injury on host susceptibility and suitability for D. suzukii. This study examined the role of previous fruit injury on adult D. suzukii survival, adult production, and host susceptibility, with injury referring to physiological splitting, disease, and vertebrate feeding. Results indicate that intact raspberries, blueberries, and table grapes are susceptible to oviposition by D. suzukii and the presence of injury increases survival of both male and female flies. When fruit was injured, berry infestation levels increases, but this did not always translate into increased adult populations. We found that the proportions of D. suzukii infested fruit were significantly higher for injured versus intact fruit. When comparing adult emergence for intact and injured fruit, only table grape and cherry tomato had significantly higher adult counts for injured berries. Overall, adult emergence per injured fruit for raspberries of 19.77 was significantly higher than all other fruit types tested, with 2.87, 3.57, and 3.43 adults for cherry tomatoes, grapes, and blueberries, respectively. Results suggest reducing previous injury in ripe fruit may facilitate more effective management of D. suzukii populations.