Staying free of apple maggot

These dimpled apples show telltale signs of apple maggot eggs deposited under the fruit skin.

British Columbia, Canada’s southern interior remains the only apple-producing region in North America free of the apple maggot, thanks to geographic barriers and ongoing campaigns to stave off its introduction.

A quarantine imposed by the Canadian Food Inspection Agency in 2006, when the apple maggot (Rhagoletis pomonella) was discovered in the lower mainland of British Columbia, has so far prevented its spread into the interior. The quarantine makes it illegal to move noncommercial tree fruit out of the designated quarantine areas, which include all of the Fraser Valley, Vancouver Island, coastal British Columbia, and 22 of 39 counties in Washington State.

Regulations require that all fruit and nursery stock coming into the province be certified free of apple maggot. Commercial nurseries in the lower mainland are required to meet protocols, and inspections are conducted on stock moving into the interior at both its origin and destination.

But the bigger concern is that a careless or unknowing person transporting infested material will introduce the pest into the interior. That already occurred with the apple clearwing moth, which was detected for the first time in Kelowna last summer after trees were transplanted from the Similkameen Valley, where there is a high degree of clearwing moth infestation.

"Because we have a natural mountain barrier between the lower mainland and the Okanagan, it’s not going to move by itself," said Kara Soares, program officer, plant protection, with the Food Inspection Agency.

"We regulate the commercial people, so we’re not that concerned about them, but the big question mark is the public moving materials into the Okanagan."

A working group that includes the B.C. Ministry of Agriculture and Lands, Food Inspection Agency, B.C. Fruit Growers’ Association, and representatives from apple growers in the lower mainland was formed to raise awareness of the threat and to prevent infestation in nonquarantined areas.

Soares said public awareness is being accomplished by a multipronged approach that includes setting up booths at apple fairs and horticulture shows, and distributing pamphlets at farmers’ markets and to people coming into Canada at customs throughout British Columbia.

As well, signs are put up from August to September on the highway near Hope, British Columbia, a midpoint between the interior and coastal regions.

The B.C. Fruit Growers’ Association also has ongoing campaigns, including attempts to convince the ministry of transportation to allow permanent and more visible signs.

"We failed to convince the ministry to allow us to put up large signs that could be read by motorists traveling at highway speeds," said B.C. Fruit Growers’ President Joe Sardinha. "We ended up getting signs that were two feet by two feet and not the size that we deemed to be effective in communicating to the public. We were also given provision to provide some material at various rest stops on the No. 1 corridor, particularly before Hope, and we did effectively communicate to the public through local radio stations in the Chilliwack area."

The association is also lobbying the ministry of the environment to refrain from planting possible host trees such as hawthorn for riparian habitat enhancement.

"We don’t want further planting of that since it could become a conduit for the insect to somehow migrate to the Okanagan if there is a continuous stream of these host trees into the interior," he said.

However, Soares said the Food Inspection Agency’s quarantine and inspection process should prevent that from happening.

"Anything moving from the lower mainland—including hawthorns and cherry trees—into the Okanagan are required to meet the same requirements," she said. "Hopefully, we have mounted a campaign so the nurseries in the interior know the situation and the material they sell to the public would either be grown in the Okanagan or meet the requirements from the lower mainland."

The Food Inspection Agency regularly surveys high-risk sites, fruit stands, organic growers, and abandoned urban high-risk areas. In addition, increased apple maggot trapping along the Canada-United States border is carried out to detect the potential spread of populations in adjacent areas south of the border.

The apple maggot is indigenous to North America and has been a serious pest of apples in Canada for more than 100 years. The first official record of the pest was at Aldolphustown, Ontario, in 1896. It is now widespread throughout eastern Canada, with the exception of Newfoundland.