Two products under development by Oregon State University could give Northwest berry growers new options for controlling the spotted wing drosophila, a particularly harmful type of fruit fly.
One product in particular, described as an “artificial fruit” that lures the pests away from the berries without directly competing against the crop, has Bernadine Strik excited.
“This is cutting-edge work,” said Strik, a berry crops specialist for OSU. “These patent-pending products have me doing a happy dance.”
Details about the product were limited — the patent is, after all, still pending. But Valerio Rossi-Stacconi, who works in the OSU Department of Horticulture, said it is a food grade attractant that can work for both conventional and certified organic growers.
Trials have shown the product reduces the number of fruit flies in berries by as much as 76 percent, Rossi-Stacconi said.
“We are very happy about this,” he said. “These keep the insect from the fruit throughout the whole fruiting process.”
The “artificial fruit” development may be available commercially by 2020, Rossi-Stacconi said.
Researchers shared the latest updates and information with about 40 growers June 6 during Strawberry Field Day at the OSU North Willamette Research & Extension Center in Aurora, Ore.
The other product, designed for blueberries to thicken the skin and protect against the flies, could be available as early as next year.
Spotted wing drosophila is troublesome for berry and stone fruit growers because, unlike other drosophila species, it infests them early during ripening, rather than later as they rot.
According to a study by the Giannini Foundation of Agricultural Economics at the University of California, yield losses can range up to 80 percent depending on the crop and location. In 2008, Oregon, Washington and California accounted for 76 percent of total U.S. raspberry, blackberry, strawberry, blueberry and cherry production.
Assuming maximum yield loss, the combined loss at the farm gate for all three states would be approximately $2.5 billion, including $1.5 billion for strawberries alone.
Oregon grows relatively few acres of strawberries, with just 1,800 statewide. Most are sold to food processors, though Strik said growers have increasingly tapped in to fresh markets over the last 15 years, which has added value to the crop.
“They are really relying on that higher value fresh market,” Strik said. “That has really helped our growers stay competitive.”
The field day also gives growers the chance to hear from experts about the latest information and cultivars to adopt in their fields, Strik said. Other presentations included fungicide resistance and an evaluation of the newest strawberry selections in breeding plots at the research station — with names like Sweet Sunrise, Puget Crimson and Rutgers Scarlet.
“Here’s an opportunity where they can come compare the varieties being grown, and see some of the stuff we are close to potentially naming,” Strik said. “We also want their input.”
Virginia Stockwell, a research plant pathologist with the USDA Agricultural Research Service in Corvallis, Ore., said fungicide resistance is now present in Oregon strawberries. She led a study isolating the fungus that causes gray mold in strawberries, known as Botrytis cinerea, and exposing it to several different fungicides.
The results showed resistance to multiple fungicides was common, Stockwell said.
“The number of tools you have to manage the disease is greatly limited,” she said.
Stockwell urged growers to use multiple methods to control gray mold. It is especially important, she said, to limit where spores can grow by keeping a dry canopy and clean field.
“That’s the cycle we’re most concerned with, is spore production,” she said.