It’s been almost five years since a quarantine was imposed on the Methow Valley to keep the apple maggot from spreading, but consistent findings of the pest in other parts of the county mean that Okanogan County could soon get its second quarantine area.
Last year, the Washington State Department of Agriculture (WSDA) set 263 apple maggot traps in pest-free areas of Okanogan County and found 35 positive sites, with a total of 260 adult flies and 720 pupae, WSDA Public Information Officer Amber Betts said. All the flies and pupae were found in wild hawthorn, not in fruit trees.
Inspectors try to control the maggot by removing trees and using pesticides. But once larvae are found in hawthorn berries, eradication is no longer an option and a quarantine becomes the only way to protect growers in pest-free areas, according to WSDA.
Apple maggot flies lay eggs beneath the skin of apples or in hawthorn berries. After they hatch, the larvae eat the fruit and then drop to the ground to pupate. Pupa overwinter in soil and hatch as adult flies in spring or early summer.
Once a quarantine is imposed, people cannot bring home-grown fruit outside the quarantine area, and fruit and vegetable scraps and green waste must be separated from regular trash.
Local infestations
Since 2021, the Tri-County Horticultural Pest and Disease Board, which covers Okanogan, Chelan, and Douglas counties, has found multiple life stages, with the largest concentrations in the northern part of the Okanogan County, pest board Director Will Carpenter told the Okanogan County commissioners at the end of May.
The most serious infestations were at two large sites. At one, the pest board was able to remove the host vegetation, but the other infestation is in wild hawthorns along a river, where eradication and pesticide use are not possible, Carpenter said.
Initially the state’s Apple Maggot Working Group was going to recommend a countywide quarantine, but Okanogan County’s apple industry has narrowed it to the most affected region, from Ellisforde to Oroville, Carpenter said. Quarantining an area smaller than that wouldn’t address the problem, he said.
The county’s fruit industry has backed those boundaries, but there are other stakeholders, including haulers, who would need special permits to truck the fruit outside the quarantine, Carpenter said.
The county’s apple industry will propose a new quarantine area, which triggers WSDA’s rule-making process, an assessment of business impacts, and public-comment opportunities, Betts said. The final quarantine boundaries could change after the rulemaking process, she said.
WSDA determines quarantine boundaries based on the feedback, but the final call lies with the state Director of Agriculture.
Controlling apple maggot is a priority for the state’s apple industry — the largest in the country — since infestation could seriously affect the domestic and overseas market.
