As we've reported previously, the fly is native to Asia and apparently spread to California in 2008. From there, it migrated to Oregon and, in August 2009, began attacking the late stages of blueberry, raspberry and peach crops.
Some Oregon growers reported losing 20 percent of their berries and up to 80 percent of late-variety peaches. Within weeks, researchers determined the fly was present in 15 counties, from Jackson County in southern Oregon, up the Willamette Valley, east through Hood River and Wasco counties and as far as Umatilla County.
The fly is unusual because it attacks ripe and ripening fruit, while most fruit flies are attracted to rotting produce. Its name comes from the distinctive spot at the tip of males' wings.
Female flies, equipped with a saw-toothed ovipositor, cut into the fruit skin and lay eggs just below the surface. The pinprick damage goes undetected until the larvae hatch and begin feeding, and the fruit collapses in a gooey mess. Thin skinned cherries, blueberries and raspberries are among the fruit and berries susceptible to attack.
Crop damage is a serious economic issue. Oregon's blueberry crop alone was valued at $117 million in 2011 and $108 million in 2012. The cherry crop value was $77 million two years ago and $74 million last year.
Farmers have been able to kill the fly with sprays they use for other fruit flies, but each spraying adds to cost and reduces profit.