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Posted 25 November 2013. PMN Crop News.

Fruit Fly Pest Can Prove Harmful to Crops, Advises West Virginia University Extension Expert

Source: West Virginia University Press Release.

Morgantown, West Virginia (November 4, 2013)--Growers of tomatoes, peaches, raspberries and other soft-skinned fruits and vegetables, as well as ornamentals, may have a new pest to fight. The spotted wing drosophila infests and lays eggs inside fruit, ruining the crop.


“Farmers across the state should prepare to control the SWD,” explained West Virginia University Extension Service Consumer Horticulture Specialist Mira Danilovich. “Unchecked, it is a menace to harvests.”

There are reports of the SWD in 16 counties in West Virginia. Its largest presence is in the Eastern Panhandle and the southeastern counties that border Virginia.

SWD infested fruit becomes soft, appears bruised, collapses on itself and can develop fungus. Female flies can lay several hundred eggs in their two-week lifetime. Eggs laid in the fruit have two “breathing tubes” that stick out and look like two fine hairs.

Adult flies are only 2 to 3 millimeters long and have a yellow-brown body with large red eyes. A distinguishing characteristic is that males have a dark spot at the edge of each forewing and two dark bands on the front legs.

“SWD are a big threat in the spring, summer and early fall seasons,” Danilovich says. “If you find them in your orchard or garden, there are a few control options.”

To check your garden for the SWD flies, Danilovich suggests using apple cider vinegar as bait in a trap.

If you suspect SWD are in your fruit, place the fruit in a cup of warm salt water. If the fruit is infected, the larvae will exit to escape the salt.

The integral part of controlling this pest is sanitation. Remove all the soft, over-ripe and fallen fruit throughout the season and after the harvest to limit the pest’s development and expansion.

Danilovich’s recommendation for chemical control in organic settings are insecticides Entrust 80 WP (spinosad) and Pyganic 1.4 EC (pyrethrum).

Farmers have also had success controlling the flies by surrounding their fruits and vegetables with plants favored by their predators, Lacewings and Parasitic wasps. Lacewings are attracted to a variety of pollen producers such as dandelions and Queen Anne’s lace. Parasitic wasps are attracted to plants in the carrot, mint and aster families.

Both the West Virginia Division of Natural Resources and WVU Extension track SWD presence in the state. If you find what you suspect to be SWD, report it to your local county office of the WVU Extension Service or your regional office of the WVDNR.

For additional information on other pest and control options contact your local county office of the WVU Extension Service, or visit

Cassie Waugh