Invasive Japanese beetles have been wreaking havoc on farms and in gardens across the East Coast and Midwestern United States for decades. Beetle larvae and adult beetles eat the roots, leaves, and flowers of many important agricultural and ornamental plants and trees.
New research shows that this invasive species may also be a significant threat to the habitat and survival of one of America’s favorite insects: the monarch butterfly.
Monarch butterflies depend on the native plant milkweed for habitat and food throughout their migration routes, from Mexico to Canada. Japanese beetles have been found feeding on milkweed flowers, decreasing their fruit and seed sets, and disrupting the next generation of plants. Monarch butterfly populations have already decreased dramatically--around 90%-- in the past 20 years, primarily due to habitat loss, including milkweed decline.
In 2016, the Oregon Department of Agriculture detected Japanese beetles in and around Washington County. ODA recognizes Japanese beetles as a threat to Oregon’s economy and natural ecosystems, and is starting its third year of its eradication and prevention project.
Read more about the study from the University of Kentucky.
[TAGS: Invasive Species, Japanese Beetle threat]
How can you identify a Japanese beetle?
Japanese beetles have three main identifying characteristics:
The Japanese beetle is the only beetle in this area that has all three of these characteristics. There are a few other beetles in the area, both native and non-native, that are also metallic or otherwise look similar. Check out our Japanese beetle look alike guide to see who’s who.
Examples of common beetles and pests that ARE NOT Japanese beetle:
What to do if you come across some beetles?
If you are within the treatment area and see adult Japanese beetles, then the ODA advises that you dispose of them in a container of soapy water. Using store bought insecticides will not significantly decrease Japanese beetle populations.
If beetles are observed outside the treatment area, please put the specimen in a container or bag and email or call ODA at the contact information provided below.
How long will this last?!
Japanese beetles are already an issue being addressed in Washington County, and the issue can’t be solved overnight. It may take up to 5 years to eradicate the population entirely.
How to help be part of the solution!
Cooperation from those in the treatment area is critical to protect Oregon’s gardens and agricultural economy! Here’s what you can do to help:
[TAGS: Japanese beetle threat, Japanese beetle basics, Beetles in Oregon, Invasive species]
Beetles can be moved in yard debris through the removal and movement of items such as sod and grass clippings. The risk of moving beetles is highest over the summer when adult beetles are emerging from the soil and moving around to feed and find mates.
It is very important that beetles are contained within Washington County while treatment takes effect. Containment efforts are ramping up, with a quarantine on all yard debris still in effect and expanding in 2018. Residences will receive electronic notices from Oregon Department of Agriculture, along with other communications planned throughout the summer.
For more information about the quarantine check back on our Prevention page for the most recent information.
[TAGS: Beetles in Oregon, Japanese beetle basics, Japanese beetle threat, Invasive species, Gardeners, Quarantine, Residents, Landscapers, Washington County, Yard debris]
Wherever you find Japanese beetles here in the United States, you find extensive damage to plants. Many areas of the United States are infested with Japanese beetle. Above you can see a clear picture of the devastation caused by these infestations that we do not want in the Pacific Northwest.
The issue is that the beetle likes many of the plants that we like to eat and grow in Oregon. The small breeding population of Japanese beetle in Washington County threatens Oregon’s agricultural economy and natural ecosystems. In order to prevent a population explosion of Japanese beetle, Oregon Department of Agriculture proposes to treat the affected areas in the spring of 2018, continuing with annual treatments until 2021 if necessary.
The Oregon Department of Agriculture has been lucky to learn from experts and invasive species managers from around the world who have a long history of combatting Japanese beetle. Find out about the unique proposed plan for treatment in Oregon, here: www.japanesebeetlepdx.info/treatment
Photographs top left and right provided by Mike Reding, USDA, captured in Ohio, 2007. Bottom left and right provided by Whitney Cranshaw lab, Colorado.
[TAGS: Japanese beetle basics, Japanese beetle threat, Invasive species, Gardeners]
PLEASE NOTE: THIS POST IS AN ARCHIVE FROM 2017.
Below is a sample of the plant damage that has been seen in the Cedar Mill area in the summer of 2017 as a result of the infestation of Japanese beetles.
Damage on Rosa sp. from the Japanese Beetle. Photograph by Oregon Department of Agriculture.
Japanese beetle caught feeding on a flower. Photograph by Oregon Department of Agriculture.
Live beetle bites into unidentified plant leaf. Photograph by Oregon Department of Agriculture.
Header photograph by Whitney Cranshaw, bugwood.org