By Ashley Toland 

In 2024 the Oregon Department of Agriculture (ODA) completed its eighth year of treatment for the Japanese beetle (JB) eradication program in the greater Portland area. Most properties were treated with a single application of the granular larvicide Acelepryn® G (Chlorantraniliprole) on lawns and ornamental planting beds. This season the granular treatment area included approximately 4,500 properties spread over approximately 1,300 acres. The successful eradication of several small pockets of beetles allowed the treatment area to be almost half the size it was in 2023. 

A large infestation in and around a single farm has made for a majority of Japanese beetle trap catches since 2022. Beetles were first detected on the farm in 2020, but ODA was not able to treat until 2023. ODA treated the edible plants with a product called Altacor® (Chlorantraniliprole), which is similar to the product used in the rest of the treatment area but is labeled for use on edible plants. Since the infestation was so severe at the farm, two treatments were conducted in 2024: one larval treatment and one supplementary foliar spray treatment targeting adults.

In 2024, ODA placed 10,272 traps throughout the state. ODA trapped 5,467 Japanese beetles, a 15% decrease from the number of beetles trapped in 2023. However, most trap catches (~75%) were isolated to the one small farm. Only 1,348 beetles were trapped outside the farm, similar to the numbers trapped outside the farm in 2023. 

The treatment area will continue to shrink this season, as the planned 2025 map is 950 acres or a 30% decrease from the 2024 map. The treatment area shrinking in size shows that ODA is nearing its goal of eradication, as we have eliminated many small pockets of JB throughout the Portland area. To view an interactive map of the 2025 treatment area please visit this site: ODA.direct/jbmap. 

ODA is getting very close to reaching our goal of the eradication of Japanese beetle from Oregon, and the continued support of the public is needed to finish this project. If you are in the treatment area and have any questions or concerns about the project, please do not hesitate to email Japanese.beetle@oda.oregon.gov. And remember, if you have not responded to requests for consent for treatment, please do so as soon as possible.