Washington state agriculture officials have expanded the boundaries of the Japanese beetle quarantine in the central part of the state after examining trapping data from the 2023 season.

While the original quarantine was established in the Grandview and Sunnyside areas, the new rule set by the Washington State Department of Agriculture expands the quarantine to encompass new areas where beetles have been caught, primarily in Sunnyside and west of Grandview.

Soil samples were added as regulated articles and the rule specifies conditions governing the movement of soil samples from quarantined areas to non-quarantined areas. The emergency rule also requires businesses located in the quarantine area selling regulated articles under WAC 16-470-710(4) or (7) to post signage developed by WSDA clearly stating that regulated articles purchased cannot be transported outside of the quarantined area.

The emergency rule amendment clarifies that under WAC 16-470-710(7), “cut flowers for decorative purposes” includes those flowers that are exposed to open-air environments during their harvest, transportation, or trade. Lastly, the amendment adds a condition for the transport of cut flowers grown in the quarantined area to areas outside the quarantined area.

Emergency rules are in effect immediately and last for 120 days. Officials will also begin the process of making the emergency rule permanent.

Three-year effort

For the past three years, WSDA has taken extensive measures to reduce the spread of the beetle with the goal of eradicating it. These measures include treating area properties with a pesticide, trapping, and establishing a quarantine.

These efforts reduced Japanese beetle catches in 2023 compared to the years prior; however, detections were found over a wider area including as far away as Pasco.

Community members can help by trapping, reporting, and killing the beetles on their properties, WSDA officials said. Residents and businesses must also follow the quarantine to prevent spreading the beetles by not moving items known to transport beetles outside of the quarantine area.

Adult Japanese beetles are metallic green and brown and have little tufts of white hair on their sides. They emerge – usually from lawns or in other soil – in the spring and feed throughout the summer. From fall to spring the grubs (larvae) overwinter in the soil and slowly develop into mature adults ready to emerge again in the spring.

To limit the need to move yard debris and other plant material outside the quarantine area, WSDA has established a drop-off site available during the adult flight season, May to October. Businesses and residents can take all accepted items to the Japanese Beetle Response Yard Debris Drop-Off at 875 Bridgeview Rd., Grandview, WA 98930. There is no charge for disposal.

Those moving out of the quarantine area will not be able to take any of the regulated items with them.

For questions or to give feedback, contact Jill Wisehart at [email protected] or 360-878-0298.

Source: Washington State Department of Agriculture