Spotted Wing Drosophila Hits Oregon

Oregon State University Cooperative Extension scientists issued a pest alert this week after finding infestations of Spotted Wing Drosophila (SWD) in several berry crops.

They have just confirmed findings of SWD in blueberries in Philomath, Benton County, OR, and have found suspect maggots (larvae) in wild blackberries, red raspberries and some leftover late-hanging Marion blackberries east of Corvallis. In addition, maggot samples from the North Willamette Research and Extension Center (Aurora, OR) are also being reared to confirm fly identity. Continued searches for SWD are currently being conducted outside Corvallis over the next weeks.

The finds didn’t come as a complete shock, as the SWD did considerable damage to cherry and several berry crops this past summer in California. More recently, SWD was found in several berry crops in western Washington.

There are 3000 species of Drosophila, commonly known as vinegar flies, but only two have been found to be harmful to crops, of which SWD is one. The SWD can infest and cause a great deal of damage to ripening fruit, as opposed to overripe and fallen fruit that are infested by most of the other Drosophila species.

Scientists say it is crucial to find infestations of this pest as early as possible when the infestations can still be treated effectively, as the SWD is a potential serious pest in fresh fruit production systems. OSU Extension researchers are recommending that if the state’s growers suspect they have SWD in their fruit, it is essential that samples of fruit or adult flies be sent directly to: Jim LaBonte, Oregon Dept. of Agriculture Plant Division, 635 Capital St. NE, 97391-2532, Salem OR, in order to positively identify adults. This will aid OSU, ODA and USDA researchers to direct their research efforts during the coming crop season.