2017-07-21

Spotted Wing Drosophila

Photo Credit: Hillier Lab

Spotted wing drosophila SWD (Drosophila suzukii) is a vinegar fly closely related to Drosophila melanogaster (the common vinegar fly). A native to Southeast Asia it is a serious new fruit fly pest of soft fruit and berries. It was first recorded in 2008 in California.

In general most species of fruit flies infest overripe, fallen or decaying fruit and are present in the late summer. However, spotted wing drosophila lay the eggs inside ripening fruit before the harvest, contaminating the fruit with larvae, causing it to become soft and unmarketable.

So far the mid- or late summer production of  raspberries, strawberries, blackberries, and blueberries have been affected the most, but SWD can also infest cherries, plums, peaches, grapes or any other soft thin-skinned fruit. By now SWD has spread throughout 28 states in the US and through 6 provinces in Canada.

SWD is about 2 – 3.5 mm long with a 5 – 6.5 mm wingspan. In general it looks like other fruit and vinegar flies but the males have a distinct dark spot at the end of each wing tip (the females don’t have spotted wing tips). They have a yellow brown body with darker bands on the abdomen and they have red eyes. SWD larvae are small, cylindrical and white, and about 3.5 mm long.

Information provided by the Hillier Lab and partially excerpted from BC Ministry of Agriculture.

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