Fall 2013

>> Spring 2014
>> Fall 2013
>> Spring 2012
>> Fall 2011
>> Spring 2011
field day

SWD Changing the Economics of Blueberry Production

Oregon blueberry growers sprayed earlier and more often for spotted wing drosophila (SWD) in 2013 than in any previous year, according to an Oregon State University Extension entomologist.

As a result, control costs soared.

Vaughn Walton estimated the vinegar fly cost growers upwards of $7.5 million this year, higher than any previous year, including last year’s former record high of $6.05 million.

“This year, because of a mild winter and warm spring, we had earlier populations, and they were very much sustained as the season progressed,” Walton said.

Walton calculated sprayer costs, chemical costs, yield loss to fruit drop and fruit left unharvested to reach his total. He estimated that growers increased their average number of sprays from five in 2012, to six or seven in 2013.

“At this stage, it appears as if spotted wing is changing the economics of growing blueberries,” Walton said.

In general, growers were able to stay ahead of the pest, Walton said, thanks in part to a new model entomologists use to predict the fly’s population. The model, called a population model, is similar to a degree day model, but more complex. It takes into account a pest’s reproductive potential, developmental potential and mortality factors, all of which are based on environmental conditions.

“We ran that model in April and we saw a tenfold population increase compared to the previous year at that early stage,” Walton said.

Growers responded to the research community’s warnings by monitoring and managing for the pest in the earlier varieties for the first time, Walton said.

Growers did suffer some losses in late-season varieties, as processors reported that they downgraded some deliveries because of the presence of the pest.

Originally from Japan, the SWD first was spotted in Oregon in the Willamette Valley in 2009. The fly has since spread, until it now is in nearly all the major fruit growing regions of the Northwest.

It also now has been reported in all the major blueberry production areas of the U.S. Walton said researchers have learned a lot about the pest in the few years it’s been here. It feeds only on ripe and ripening fruit. Green fruit is believed to be less susceptible. (Work is ongoing to determine when susceptibility increases.) And they’ve learned that SWD has a wide host range involving mostly soft-skinned fruits, such as cherries, blackberries, blueberries and peaches.

Top chemical controls for the pest include the pyrethroid Mustang Max and the organophosphate Malathion. For organic growers, Entrust, with spinosad, has proven effective, Walton said.

Researchers are advising growers to install drip irrigation when planting new fields to blueberries or replanting fields. Drip irrigation provides better opportunities for controlling the pest with pesticides than overhead irrigation, given that overhead irrigation tends to wash pesticides off leaves.

There is still a lot researchers don’t know about the pest, Walton said. Eventually, Walton hopes the research community can provide growers a playbook of cultural and biological controls that can cut treatment costs by a third. Researchers recently brought back from South Korea a parasitoid that they hope will serve as a biocontrol agent for SWD.

On a positive note, Walton said he doesn’t expect SWD to show up as early as it did in 2013 on a regular basis. “I don’t think you will see this very often,” he said.

Growers can access information on SWD at www.spottedwing.org .

Chairman's Report >>>

Movement up in Korea >>>

Market Report: Prices Low in Summer Fruit; In Frozen, Lots of B, But A Grade in Short Supply >>>

New Research Projects Generating Interest >>>

Marketing Program

SWD Changing the Economics
of Blueberry Production

Pesticide Update:
Bee Advisory for Neonicotinoid Insecticides; Changes to Sandea Herbicide Label

USDA Approves National Assessment Hike >>>

Highbush Blueberry Council Blueberry Alert System >>>