view current print edition




Pest grabs attention in Northwest

by Lora Abcarian | October 15, 2009
Researchers, members of the fresh fruit industry and governmental officials have created a task force whose focus is to take proactive measures to stave off the impact of the newest pest found in Oregon and Washington.

Bruce Pokarney, director of communications for the Oregon Department of Agriculture, said that drosophila suzukii - commonly known as the vinegar fruit fly - reared its head this past September in the Willamette Valley.

"We have had general issues with fruit flies, which eat rotting fruit," he told The Produce News in early October. "What makes this guy unique is this one likes fresh fruit. The population exploded at the end of the [2008] season."

Initial reports came out of California after the pest was discovered in cherry orchards. "We started looking for it since California had it," Mr. Pokarney stated. "There was a peach orchard here in Salem that really got hit hard and fast. Since then, we've found it in several counties."

The vinegar fruit fly has also been found in the Seattle area. But, "There is nothing east of [Washington's] Cascades as far as I know," said Mr. Pokarney.

The pest is native to Japan, which has a long history of dealing with the fly, said Mr. Pokarney. Drosophila suzukii preys on apples, cherries, grapes, peaches, raspberries and strawberries. The female fly deposits eggs into fruit with a long ovipositor. The maggots hatch in about three days and begin to feed on the surrounding healthy fruit. As fruit flesh is consumed, the fruit begins to collapse and rot.

The presence of the vinegar fruit fly is new in Oregon. Mr. Pokarney said that the fly is likely present in a number of states but wasn't on the radar screen. "Oregon State University, the U.S. Department of Agriculture's Animal & Plant Health Inspection Service and industry groups have come together to share information and determine what isn't known," he said. "We want to develop management practices to mitigate the problem before next season."

The first meeting took place the week of Sept. 21, shortly after the Oregon outbreak. "It is a serious situation, but we want to be vigilant," Mr. Pokarney added.

"It's gotten everyone's attention," he commented. The fly has a one-week life cycle. Although the pest can reproduce for 16 generations during a single season, he added, "Some fruit isn't going to be ripe that long."

The vinegar fruit fly is able to withstand cold temperatures, and he said that experts are expecting the pest to overwinter. As a result, he said, it is important for the task force to get a handle on control and potential eradication measures, which range from cultural practices to pheromone disruption to crop spraying.

Extensive work is being undertaken to learn more about variables during the 2008 season that may have contributed to the infestation. To illustrate the depth of information, Mr. Pokarney said, "Growers are being asked about sun/shade conditions. I was really fascinated at hearing what researchers want to know."

Mr. Pokarney was asked how the situation will affect Oregon's organic fruit producers. "There is a product that is certified organic that kills fruit and vinegar flies," he responded.

As the task force moves ahead to find a solution, Mr. Pokarney expects a web site to be developed to help share information. "We'll have some answers," he added. "It's not all gloom and doom."