Japanese beetles are again invading Oregon, according to Oregon agriculture officials. The beetles can be destructive to turf and all sorts of plants, so if the beetle population keeps growing, officials may launch a campaign to kill them.

Oregon, while mostly beetle-free, has been fighting the pests for more than 100 years. The bugs like to feed on some of Oregon's most notable and profitable plants -- roses, nursery plants and now marijuana could all be affected if a Japanese beetle population spread throughout the Willamette Valley or state.

More than 265 Japanese beetles were found this summer, especially in the area where Washington County and Portland meet. The state agriculture department sets traps for various pests, and the bugs that showed up indicate that enough of the non-native bugs are breeding in that area to be a permanent population.

They are mostly munching roses and other plants. An Oregon Department of Agriculture release said that the infestation likely took hold more than a year ago, but this is the first time it was detected.

"Without community action, this pest will spread and cause an increased use of pesticides by homeowners and producers of agricultural crops such as cannabis, hops, nursery plants and wine grapes," said Clint Burfitt, manager of Oregon's Insect Pest Prevention and Management Program.

Most states east of the Mississippi River have Japanese beetle problems, and more spots are popping up in Oregon, Washington and California. Usually, the beetles were carried through air cargo carriers into Portland International Airport. The agriculture department has launched eradication efforts in residential areas of Portland and Cave Junction.

So far, that has kept the pest from spreading too much. Japanese beetles are also screened for when plant material enters the country.

Agriculture officials have not made plans to target this most recent outbreak, but are doing more trapping, especially around Northwest Saltzman and Thompson roads.

-- Molly Harbarger

mharbarger@oregonian.com

503-294-5923

@MollyHarbarger