Differences in oviposition preferences of spotted wing drosophila, Drosophila suzukii, on grape varieties: recommendations for control

Spotted wing drosophila (SWD) females are unique among North American drosophilids in having a serrated ovipositor. This gives them the ability to oviposit into a diversity of fruits that are in varying stages of ripeness. As populations become established in North America, the potential for this invasive pest to cause serious economic damage in fruit crops remains unknown. We tested the oviposition preference and overall fecundity of SWD in three grape varieties grown in Washington state both in the field and in the laboratory. We chose three varieties of grape that differ in overall acidity levels as well as when in time the fruit becomes ripe. We found that SWD will oviposit in both unripe and ripe Riesling, Merlot, and Concord grapes. Development to adulthood was also supported in all three grape varieties. However, when given a choice, SWD prefers to oviposit into Riesling grapes in contrast to the other two grape varieties Merlot and Concord grapes. This data suggest that management of SWD requires specific knowledge of the grape variety and its time to peak ripeness.