Washington State Department of Agriculture officials confirmed last week that Japanese beetles have spread beyond the initial quarantine area established earlier this year.  On Thursday, December 15th, the WSDA filed an emergency rule to expand the boundaries of the internal quarantine of Japanese beetle.  The Department says the south-central Washington quarantine is part of a three-pronged effort to eradicate the invasive pest in the state.  The emergency rules are now in effect and will run for the next 120 days.  WSDA also began the process of making the emergency rule become a permanent rule.


attachment-Japanese beetle quarantine December 2022


The Department says throughout 2021 and 2022, they took extensive measures to reduce the spread of the beetle, with an ultimate goal of eradicating it.  Measures taken included treating residential and public properties with pesticide, trapping, and establishing an internal quarantine.  Despite these efforts, by the end of the 2022 trapping season, numerous Japanese beetles were caught outside of the established internal quarantine area.


“Due to this, immediate action is needed to expand the internal Japanese beetle quarantine to more accurately reflect the area of infestation in order to prevent the beetles from spreading into non-infested areas,” Camilo Acosta, project coordinator said.


Adult Japanese beetle are metallic green and brown and have little tufts of white hair on their sides.  They emerge, typically 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.


If you see a Japanese beetle, you are asked to trap it, and then report the beetle to the WSDA.  After you have done that, you are ask to kill all of the pests.  From there the Department of Ag says residents must also follow the quarantine to prevent spreading the beetles by not moving items known to transport beetles outside of the quarantine area.  Those living or working in the quarantine area need to limit the movement of yard debris and other plant material outside the quarantine area.  For those that need to drop of approved yard waste materials, can do so by visiting the Japanese Beetle Response Yard Debris Drop-Off at 875 Bridgeview Rd., Grandview, WA. There is no charge for disposal.


The WSDA first discovered three Japanese beetles in the Grandview area in 2020.  Last year the department trapped more than 24,000 beetles.  So far this year, teams have caught 23,000 beetles. Japanese beetles are highly invasive pests of more than 300 plants, including roses, grapes, and hops. The adult beetles damage plants by skeletonizing the foliage. Adults also feed on buds, flowers, and fruit on the plants and are frequently intercepted with air cargo from the eastern United States. 


If you have a story idea for the PNW Ag Network, call (509) 547-9791, or e-mail glenn.vaagen@townsquaremedia.com 

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