Assessment analyzes risk for spread of apple maggot
Ross Courtney // July 8, 2016
The PacifiClean composting facility in Quincy, Washington, is shown operational in the spring of 2015. Concerns over the spread of the apple maggot have prompted state authorities to stop composting activity, at least temporarily. (Courtesy Ryan Leong)
A trio of pest consultants has concluded that transporting urban organic waste would likely spread the dreaded apple maggot to orchards in rural Washington and recommended heating yard and food scraps before hauling them to areas the pest hasn’t already reached.
The consultants published their results in early May in a pest risk assessment, gauging the likelihood that the apple maggot would hitch a ride on compost feed stocks hauled from areas quarantined for the pest — primarily the Puget Sound region — to eastern Washington compost facilities.
Today, the 271-page, $200,000 technical document, paid for by fruit industry assessments, provides a guidebook for state officials, recycling companies, cities and counties searching for a way to meet a growing demand to compost while still protecting Washington’s most valuable agricultural commodity from one of its most feared pests.
The goal is to do both, to “co-exist,” said Laurie Davies, manager of the Washington state Department of Ecology’s Waste to Resources program, which regulates commercial scale composting.
“We don’t want solid waste to stop moving because of apple maggot,” she said. “If it doesn’t move, we have a health issue.”
About the assessment
The assessment paints an alarming picture for the spread of apple maggot, or Rhagoletis pomonella, a pest common in feral orchards and backyard fruit trees in much of western Washington but quarantined since the 1980s to prevent it from reaching the eastern Washington counties that produce apples.
The apple maggot directly attacks fruit, turning the flesh brown and mushy and causing apples to drop early. It has never been found in commercial fruit in Washington, yet many international trading partners consider it a pest of concern.
The consultants from Colorado, Massachusetts and England concluded the risk of spreading the maggot through waste hauling is “likely to occur with low uncertainty” if compost companies do not treat it first.
They traced four hypothetical routes for the maggot, called pathway analyses, each through a different eastern Washington composter, and gauged different levels of risk. Every composter handles their feed stocks, sometimes called municipal green waste or MGW, in different ways.
Overall, the risk posed by R. pomonella moving on waste from the quarantine area is unacceptable, they determined.
Tree fruit industry officials praised the report’s strong language for validating their concerns.
Their painstaking methodology left few stones unturned and little room for argument, said Mike Willett, manager of the Washington State Tree Fruit Research Commission. For example, consultants normally would run only one pathway analysis, he said.
“There was dispute about how much pest risk there was,” said Jon DeVaney, president of the Yakima-based Washington State Tree Fruit Association, which represents growers and packers. The third-party document concludes that the risk is “higher than a lot of people suspected.”
The state still has a long way to go before implementing any of the recommendations or allowing any more transfer of yard compost outside the quarantine. The state currently has imposed a moratorium on any such transfers.
The consultants, all well known in the pest control industry, suggested mechanically heating the compost material to kill all life stages of the apple maggot before moving it across quarantine lines.
Entomologists from the U.S. Department of Agriculture have shown that heating will work in small quantities but have not tested it on a broad commercial scale. (See “Dealing with apple maggot in yard waste” in the March 1, 2016 issue.)
State officials will lean on the assessment to develop protocols for ensuring the yard waste is treated, said Kirk Robinson, deputy director of the Washington State Department of Agriculture, the agency charged with preventing the spread of farm pests. They have no deadline in mind for that to happen, he said.
History of green waste
Composting, though more common as urban areas have grown, is not new.
Over the past 20 years, the state Department of Ecology has been regulating the disposal of food scraps and yard clippings from cities through composting to divert it from landfills, where it may leach into groundwater and cause greenhouse gasses as it breaks down. The Ecology Department writes the regulations while county health districts issue permits.
For years, the city of Seattle had sent much of its waste to Cedar Grove, a company with facilities in Everett and Maple Valley, helping turn compost into a business enterprise. “It is a commodity and it’s a big business,” said Davies of the Ecology Department.
However, composters in Puget Sound are running out of room, prompting local governments to seek help from eastern Washington facilities, usually located farther from metropolitan centers and closer to farmers who purchase the finished compost as fertilizer.
In 2013, the city of Seattle contracted with PacifiClean Environmental of Spokane to transport and compost the city’s green waste at a facility in Quincy, Washington. An alert fruit grower in the area read about the agreement in a local newspaper and told a state Agriculture Department official he was worried about apple maggot. That was the first the agency had heard of the issue.
Seattle’s well-publicized composting mandate for all residents took effect Jan. 1, 2015. PacifiClean began accepting the city’s waste that February.
On Feb. 3, the Department of Agriculture declared emergency authority to issue special permits for compost facilities that haul waste across the quarantine boundary, but allowed PacifiClean to continue while it worked out the details of the permit.
On June 30, 2015, the Agriculture Department issued a special permit for the PacifiClean plant, located about 6 miles south of Quincy.
Within a few days, inspectors found apple maggot larvae in apple waste in the PacifiClean processing line, according to Jim Marra, manager of the Agriculture Department’s pest management program, and the agency suspended the permit on July 10.
However, they still allowed the waste transfer if the company ground it before hauling. In August, inspectors continued to find apples they feared could provide apple maggot habitat in the waste stream in Quincy and finally put a halt to all the shipments on Aug. 18.
When all was said and done, PacifiClean processed more than 24,000 tons of Seattle waste during the seven months of operation.
Later, inspectors also found an adult apple maggot fly in a trap near Royal Organics, a Royal City compost company that in the past had accepted green waste from inside the quarantine but ceased when the Agriculture Department made the emergency rule.
The fly did not necessarily come from Royal Organics, officials said. The agency’s traps catch some adults outside the quarantine every year.
The controversy has left PacifiClean in limbo.
The company now is gauging the economic sense of the heat treatments called for in the risk assessment, General Manager Ryan Leong said. “We’re in the process of evaluating all that and trying to determine if that’s feasible,” he said.
For now, the company is unable to use the expansion made specifically for the Seattle contract that could have been worth more than $3 million per year and processed a projected 65,000 tons of waste.
“A lot of money went into developing additional infrastructure,” Leong said. He declined to reveal how much.
In the meantime, Cedar Grove has temporarily resumed taking Seattle’s waste.
PacifiClean may have landed the biggest catch with the Seattle contract, but they were not fishing uncharted waters.
Other eastern Washington companies, such as Royal Organics and Natural Selection Farms in Sunnyside, had been accepting waste from quarantine areas before the fruit industry realized it. Their respective counties permitted it under Ecology’s regulations.
Meanwhile, the state Department of Agriculture has allowed other facilities to continue.
Barr Tech in Lincoln County currently accepts municipal green waste from the Spokane area, which is inside the quarantine.
In fact, department officials are planning to redraw the quarantine boundaries to include Barr Tech’s portion of Lincoln County, reasoning that the apple maggot already is in the area, which is not home to any commercial fruit orchards anyway.
Also, the department permits the Greater Wenatchee Landfill and Recycling Center to accept solid yard waste. Solid waste does not pose as big of a threat as organic waste, Marra said, as long as the city sending it separates solid waste from organics, such as food scraps, and the landfill covers and buries the solid waste right away. Douglas County also has active pest boards and advisors who understand apple maggot, Marra said.
Fruit industry officials don’t want to completely stop the state from recycling, they said. “It’s not that the fruit industry has any problem with composting, per se,” said Willett of the research commission. But the new risk assessment calls for a long-term plan that prevents the spread of the apple maggot and treats everybody fairly.
“I believe that it argues for some level of standardization of processing,” he said. •
Determing the risk
On March 31, Washington Gov. Jay Inslee signed into law Senate Bill 6605, which requires local agencies and the state Department of Ecology to gauge — with the state’s Department of Agriculture — the risk of spreading pests when making solid waste regulations. It took effect June 9. For more information, visit 1.usa.gov/1Y4p7jn.
The three consultants hired by the state Department of Agriculture to draft a risk assessment of the apple maggot spread posed by organic waste for composting all have high credentials in the international pest management community.
—Claire Sansford of York, England, a plant pathologist known for evaluating threats for the United Kingdom and the European Union. She has been an independent
plant health consultant for three years. She previously worked 24 years for former government crop agencies in the United Kingdom, where she specialized in phytosanitary risks posed by plant waste. She was the primary author of the report.
—Victor Mastro, a private consultant in Cotuit, Massachusetts. He previously served as entomologist and laboratory director for the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, or APHIS.
—James R. Reynolds, owner of a plant health consultancy in Fort Collins, Colorado. He previously worked as the Western Regional Director for APHIS’s Plant Protection and Quarantine program.
Another consultant — Jaak Ryckeboer, an expert in hygienic safety of organic waste processing in Brussels, Belgium — reviewed the 271-page document.
The risk assessment is available on the Department of Agriculture website at 1.usa.gov/28grvZo
Ross Courtney is an associate editor for Good Fruit Grower, writing articles and taking photos for the print magazine and website. He has a degree from Pacific Lutheran University. -- Follow the author -- Contact: 509-930-8798 or email.