Natter’s Notes 

Update: Japanese Beetle

Jean R. Natter, OSU Master Gardener

No Japanese Beetle logo
Image courtesy of the Oregon Department of Agriculture

The Oregon Department of Agriculture (ODA) has an extensive website with information about their continuing efforts to eradicate the invasive Japanese beetles (JBs) from Washington County, Oregon, which is expected to require 5 consecutive years of treatment. (Treatments began in 2017..) For a history and overview of the project, including all public updates beginning with March 2017, see ODA’s website at

ODA advises that adult Japanese beetles (JBs) found within the designated treatment area should be disposed of in soapy water. If JB adults are observed outside the treatment area, capture it/them and, then, promptly notify ODA by email at or phone 1-800-525-0137.

The following is the full text of the most recent Oregon Department of Agriculture update (April 16, 2018) for the ongoing eradication effort of the Japanese beetle in Washington County:

– – – –

The Oregon Department of Agriculture has begun treatment operations of residences in Washington County as part of the second year of Japanese beetle eradication. Oregon Department of Agriculture has contracted General Tree Service to perform the applications of the larvicide. General Tree Service (GTS) worked with ODA during the first year of the project, and has worked with ODA on past eradication projects for Japanese beetle in Oregon in years prior.

The treatment area in Washington County for 2018 is approximately 2000 acres containing an estimated 6500 residences. As of Friday, April 13, ODA and GTS had treated 2,049 properties for Japanese beetle. Four application crews consisting of one ODA team lead and two General Tree Service applicators and staff meet each morning at 7:30am to prepare the day’s plans. Treatment begins at around 8:15 am when the ODA team member visits each home to inform the resident of the treatment, inspects the property for hazards or areas to avoid application, and flags the property to let the crew know it’s ok to treat. Residents are notified about treatment schedules the week before.

– JB life cycle – Adult Japanese beetles are active only during a brief window during the summer months but are capable to doing considerable damage to numerous ornamentals. Credit: Lifecycle illustration by Oregon Department of Agriculture, Thomas Shahan

There have been some delays due to weather, but mostly treatment has been able to be completed as scheduled. This is due in large part to the hard work being done by the seemingly tireless application crews and crew leads who are working long days, rain or shine, to make sure treatment is correctly and done on time. Operations are expected to continue until mid-May, with some applications planned in Douglas County and at the Portland International Airport.

Support from resident in the area has been very positive. Before treatment, we’d received over 5,000 responses from residents allowing ODA and their staff to treat the properties, including 30 Home Owners Associations allowing treatment in common areas. Tualatin Hills Parks and Recreation Department and the Beaverton School District are also supporting the project and allowing treatment to parks and school fields. Applicator crews have said that residents in the area are expressing their support for the project, with many “Thank yous” and “Get those beetles!”

Containment will begin ramping up soon, with the yard debris quarantine still in effect and expanding in 2018. Residences will receive electronic notices from Oregon Department of Agriculture this week, along with other communications planned throughout the summer.

– Chris Hedstrom, Japanese Beetle Project Coordinator

(Click the link below for PDF containing the above text and all the images.)

Japanese Beetle Update PDF

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