New apple maggot soil rules in effect

For the Basin Business Journal | August 3, 2020 1:00 AM

OLYMPIA — The Washington State Department of Agriculture (WSDA) has instituted new regulations concerning the soil being transported from apple maggot-quarantined areas to non-quarantined areas. The new rules took effect July 11.

Apple maggots are a type of fruit fly that attacks apples, as well as other plants and tree fruits, according to Karla Salp with the Washington State Department of Agriculture. The apple maggot lays eggs in apples. Once the eggs are hatched the larvae eat their way through the apple and drop to the ground, where they spend the winter. In the spring, they emerge as adults and start the cycle all over.

Since the 1980s, the state of Washington has been regulating and quarantining areas of apple maggot in the state. The quarantined areas include all of western Washington, all of Klickitat and Spokane counties and parts of Okanogan, Chelan, Kittitas, Yakima and Lincoln counties.

“The point is to prevent apple maggots from spreading to apple growing regions,” Salp said. “It is not established in many apple-growing areas.”

A statewide infestation of apple maggot could greatly affect the state’s ability to export apples. In an effort to keep that from happening, the WSDA, along with pest control boards, local counties and the apple industry, work together as a group to change apple maggot rules and quarantine boundaries.

Additionally, the WSDA sets out apple maggot traps to ensure that non-quarantined areas stay apple maggot-free, and also samples fruit and performs inspections. County pest control boards are responsible for the eradication of apple maggots found in non-quarantined areas.

The new rules surrounding the transportation of soil affects mainly nurseries in quarantined areas that ship to non-quarantined areas. Salp said that approximately five years ago, apple maggots were discovered on trees in areas that traditionally had not had the insects. The trees, which had been newly planted, came from a nursery in the quarantined area.

“If they’re selling a tree that has fruited, there is the potential that anything in the area or drip line could be hosting the apple maggot,” Salp said.

The result would be an unintentional transportation of apple maggot to non-infested areas.

The new soil regulations affect anything grown under an apple tree or in the same drip line as an apple tree at nurseries in the quarantined area. It won’t apply to plants grown in separate areas away from apple trees or plants that are shipped with the bare roots. Plants shipped with soil or grown in the drip line area will need to be certified pest-free before being shipped to non-quarantined areas.

While the new regulations mainly affect nurseries in quarantined areas, it also prevents individuals from non-quarantine areas from purchasing plants in quarantine areas and bringing them back home. For example, for someone from Moses Lake to purchase a plant in Seattle, Spokane or another quarantined area and bring it back, a phytosanitary certificate would be required. A phytosanitary certificate indicates that the plant is apple maggot-free. Salp said that while individuals can in theory get the certificate, it is very difficult. The certificates are primarily meant for businesses.

“It is really important to be aware of where those quarantine boundaries are,” Salp said. “It is really important to not transfer home grown fruit from a quarantined area to a non-quarantine darea.”

The WSDA has maps on their website that show the exact location of the apple maggot quarantine areas. The website is, and also contains more information on apple maggots.

Rachal Pinkerton may be reached via email at