Spotted Wing Drosophila

Spotted wing drosophila (Drosophila suzukii) is an invasive Japanese fruit fly that attacks cherries and many berries, such as raspberry, strawberry, blueberry, blackberry. The spotted wing drosophila has also been seen attacking figs, nectarines, and plums. It was first seen in California in 2008 and has become a serious pest.

Male ‘Drosophila suzukii’ (Judy Gallagher) CC BY 2.0

Spotted wing drosophila identification & lifecycle

Adults fruit flies are tiny (1/16" to 1/8”). They have red eyes and a brown body. Spotted wing drosophila can be differentiated from other fruit flies by a brown spot on the front outer edge of each wing. Like most fruit flies, spotted wing drosophila only live for a few weeks, but there can be as many as 10 generations each year.

Male and female ‘Drosophila’ (Shane F. McEvey, Australian Museum) CC BY 4.0

Fruit damage

Female spotted wing drosophila use a pointed ovipositor to pierce the skin of healthy fruit and then deposit 1 - 3 eggs in each location. Several females may deposit eggs in the same fruit. The broken skin surface then provides other pests and diseases with easy access. As the eggs hatch, maggots begin consuming the fruit, making it inedible.

Spotted wing drosophila management

Populations are generally not seen until the fruit is harvested. At that point, there is nothing to be done besides harvesting the rest of the crop, before eggs can hatch, and inspecting the fruit for infestation before eating.

Because this pest is relatively new to the U.S., treatments have not yet been identified. Cornell University offers instructions of how to make your own Fermented Dough Insect Trap.
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​If you see this pest in your garden, please let us know in the comments and call your local County Extension office.