Text Size:   A+ A- A   •   Text Only
Find     
Site Image
Japanese Beetle
Order: Coleoptera
Family: Scarabaeidae

Scientific name: Popilia japonica Newman
Common name: Japanese beetle (JB)

 
Identification
Adults: Bright metallic green with copper-colored wing covers and about 3/8 on and inch long and 1/4 inch wide. There are two small tuffs of white hair just behind the wing covers and five patches of white hair along each side.
Larvae: Look very similar to many other larvae that are found in the soil. Their bodies are C-shaped and creamy white with the posterior end darker. Full grown larvae are about 1 and 1/8 inches long. They spend about 10 months of its life in this stage.
Pupae:Cream colored, then light reddish brown as it matures.
Eggs: White, oval, and about 1/16 inches long. Eggs are laid in the soil.
 
Japanese beetle adult
Japanese beetle larva
Japanese beetle turf damage
 
Damage: The larvae feed primarily on the roots of turf in lawns, golf courses, and pastures, but will also feed on the roots of crops such as corn, strawberries, beans, and tomatoes. The adults feed on several hundred species of woody and herbaceous plants including maples, oaks, elms, fruit trees, grapes, berries, roses, and corn.
 
Impacts: Both the larval and adult stages can cause extensive damage and expense in agricultural and horticultural industries. Western Oregon has extensive areas and plantings which would be suitable for Japanese beetle survival and reproduction.

 
Host plants: Adults feed on several hundred species of woody and herbaceous plants. Some of the more preferred hosts include roses-especially yellow and light colored varieties, grapes, most deciduous fruit trees, shade trees, most shrubs, garden-corn, soybean, asparagus, blueberry, rhubarb, sassafras, and evening primrose, hollyhock, and many weeds. The adults typically skeletonize leaves and leave behind large irregular holes, consume flowers, and devour fruit. The grubs develop in the soil feeding primarily on the roots of turf in lawns, parks, golf courses, and pastures, but will also feed on the roots of crops such as corn, beans, tomatoes, and strawberries.
 
Distribution: The beetle has been reported in more than 22 states east of the Mississippi as well as Iowa, and Missouri. Isolated infestations have been reported in Oregon, California. Colorado, Utah, Washington, in addition to other states.
distribution maps
 
Biology and Life Cycle: Japanese beetle has one generation per year and overwinter as larvae. In mid-June to early July, adults emerge from the ground to feed on the foliage around them until mid summer with peak abundance during July and August. The adults mate and the females lay eggs intermittently during the feeding period until40 to 60 eggs are laid, usually in turf. The eggs hatch in about two weeks and the young grubs feed until late autumn when the grubs burrow 4 to 8 inches into the soil and then spend the winter inactive. When spring comes and the temperature warms, the grubs become active and feed on roots until fully grown. When fully grown the grub forms a pupa and after two weeks, the pupa becomes an adult beetle and emerge from the ground.
 
How you can help:
1. Report suspected Japanese beetle life stages to Oregon Department of Agriculture.
2. Report any extensive damage to lawns, roses, grapes, fruit or other trees and shrubs to the Oregon Department of Agriculture.
3. Cooperate with Oregon Department of Agriculture seasonal survey staff when they request permission to place traps on your property during the summer.
4. Observe quarantine regulations by not moving plant material, outdoor household articles out of Japanese beetle infested areas without certification.
What ODA is doing: Each year ODA places approximately 5,000 Japanese beetle traps across the state. Placing traps allows ODA to detect any infestations when they are small and when they are more easily eliminated.
 
Links:
Annual Report
JB pest risk assessment (pdf, 777 KB) 
 
Photo credit:
Japanese beetle turf damage: M.G. Klein, USDA Agricultural Research Service