In 2016, Japanese beetles were trapped in high numbers in the Portland area. The Oregon Department of Agriculture is working to eradicate Japanese beetle hot spots in Portland, and OSU Extension is helping with outreach, identification, and management information for this potential pest. This insect is a major plant pest that is destructive to approximately 300 species of turf, fruits, vegetables, shrubs, and trees.

Because of the highly visible damage Japanese beetles cause to turf and ornamentals, the overuse of chemical controls is a real concern. ODA, along with partner organizations, has plans in place to limit and control the spread of this destructive, invasive beetle.

Further reading:

Japanese Beetles in Oregon Extension publication: https://catalog.extension.oregonstate.edu/em9158   

Oregon Invasives Hotline: https://oregoninvasiveshotline.org

PDX Japanese Beetle site: http://www.japanesebeetlepdx.info 

If you suspect that you have an infestation, do not apply pesticides yourself. Instead, call the Oregon Invasives Hotline at 1-866-INVADER to report Japanese beetle.

Leaf damage from Japanese Beetles (Steven Katovich, USDA Forest Service, bugwood.org)

Leaf damage from Japanese Beetles (Steven Katovich, USDA Forest Service, bugwood.org)

 

 

 

 

 

Japanese Beetles feeding on roses: flickr.com/photos/georgesgewels/2643035643/, Adult on flower: Kevin D Arvin, forestryimages.org.

Japanese Beetles feeding on roses: flickr.com/photos/georgesgewels/2643035643/, Adult on flower: Kevin D Arvin, forestryimages.org.

The following is a list of trees favored by Japanese beetle, though they are unlikely to kill a medium to large-sized tree:

  • American mountain-ash
  •  Apple, crabapple
  • Beech
  • Birch
  •  Black walnut
  • Cherry
  • Crape myrtle
  • Elm
  •  Holly
  •  Horse chestnut
  • Larch
  • Linden
  •  Maple
  •  Oak
  • Peach, apricot
  • Plum
  • Poplars/cottonwood
  •  Sassafrass
  • Western red cedar, arborvitae  
  •  Willow