By Cathy McKenzie, WSU Extension
MOUNT VERNON, Wash. – Entomologist Lynell Tanigoshi and his colleagues at Washington State University have devised an effective system to help soft-fruit growers control their “Public Enemy No. 1” – spotted wing drosophila, a type of fruit fly.
The system – insect resistant management – rotates spraying with a variety of chemicals to reduce resistance to insecticides.
“We’re trying to establish a bio-fix for growers to be able to begin their pesticide treatments when berries are actually ripening, and then – based on their specific crop and growing conditions – apply appropriate pesticides every six to eight days through harvest,” Tanigoshi said.
The goal is to find intervals when pesticide applications are not needed and to determine what rotations work best, he said: “We’re trying to educate people to make intelligent choices based on scientific evidence so we can move in the direction of finding more ways to get off our addiction to calendar sprays.”
“Spotted wing drosophila has established itself as the most economically damaging pest to blueberry and caneberry production in the Pacific Northwest,” he said.
U.S. Department of Agriculture statistics show that the blueberry harvest in Washington and Oregon for 2012 accounted for 15,900 acres worth $192 million in fresh and processed fruit. The red raspberry harvest accounted for 11,000 acres worth $44.5 million, followed by 3,300 acres of strawberries worth $25.3 million.
Tanigoshi’s advice is part of a report, “Spotted Wing Drosophila in Berries – 2013 Findings,” which he and fellow entomology team members Beverly Gerdeman and Hollis Spitler compiled. The report is a result of the team’s small fruit pest management program research, which focuses on new and cost-effective ways to help the state’s more than $100 million small fruit industry.
“After four years of fighting this insect, we better understand the biology and behavior of spotted wing drosophila,” Tanigoshi said.
The next step will be to develop new mode-of-action insecticides that will prevent tolerance and target different sites in order to interrupt the fly’s reproduction cycle, which in the Northwest can be as rapid as three to four generations hatched each year.
Lynell Tanigoshi, entomology professor, WSU Mount Vernon Northwest Research and Extension Center, 360-848-6152, firstname.lastname@example.org