Spotted Wing Vinegar Fly can devastate small fruit crops

Samples of small fruit crops in Tennessee

Many small fruit crops in Tennessee, like blackberries, strawberries and blueberries, are facing a new invasive pest: the spotted wing vinegar fly. Photo by Scott Bauer, courtesy USDA ARS.

NASHVILLE, Tenn. – Experts with the University of Tennessee Institute of Agriculture are sounding the alarm on a tiny new pest that can cause significant damage to many fruit crops.

The spotted wing drosophila (SWD) is a vinegar fly (sometimes inaccurately called a fruit fly) from Asia.  It was first detected in California in 2008. In 2011, SWD had reached blueberries in East Tennessee. By 2013 SWD damage had spread to 23 Tennessee counties, from Greene County in the east to Gibson County in the west.

The female SWD is equipped with a serrated egg laying structure called an ovipositor that allows her to pierce the flesh of healthy fruit and insert tiny eggs inside. The piercing of the fruit allows yeast, fungi and other microorganisms to enter and begin the process of decay. Once the larvae hatch, they feed on the fruit, causing it to further decompose.

The SWD targets strawberries, blueberries, blackberries, raspberries, grapes, figs, persimmons, cherries and other soft, thin-skinned fruit. Berries are especially susceptible. Wherever it has been found, the SWD has caused considerable damage to fruit crops.

Because this pest is so new to the area, entomologists are still evaluating the best methods for control. Frank Hale, a UT Extension entomologist, says the first step is knowing whether the pest if present. He recommends setting traps within fruit crops baited with yeast, sugar and water. If this invasive pest is detected, he says weekly insecticide applications should begin as soon as the fruit show the first sign of their ripening color.

You can speak directly with UT experts about this and other crop pests at several UTIA-sponsored events this summer, including the Fruits of the Backyard Field Day on Tuesday, June 17, at the Middle Tennessee AgResearch and Education Center in Spring Hill and the Summer Celebration Lawn and Garden Show on Thursday, July 10, at the West Tennessee AgResearch and Education Center in Jackson. For more information on these events visit the website for UTIA Field Days and Special Events.

You can also find more information about SWD on the UT Institute of Agriculture’s Soil, Plant Pest Center Facebook page, or by calling your local UT Extension office, located in every county in the state.

UT Extension provides a gateway to the University of Tennessee as the outreach unit of the Institute of Agriculture. With an office in every Tennessee county, UT Extension delivers educational programs and research-based information to citizens throughout the state. In cooperation with Tennessee State University, UT Extension works with farmers, families, youth and communities to improve lives by addressing problems and issues at the local, state and national levels.



Frank Hale, professor, Department of Entomology and Plant Pathology, 615-832-6802,

Ginger Rowsey, UTIA Marketing and Communications, 731-425-4768,