Japanese Beetle

Pest Description

• adults: 1/2 inch long; metallic green head and thorax; bronze wing covers; five white hair tufts along each side of the abdomen with an additional pair on the last segment
• larvae: 1/8 – 1 inch long; c-shaped; cream colored with a grayish rear end; yellow-brown head with three pairs of legs

Host Plants, Diet & Damage

• more than 300 plant species of ornamentals, trees, shrubs, turfgrass and vegetables
• adults prefer leaves, flowers, fruit, and sometimes stems of rose, maple, elm, birch, linden, apple and stone fruits
• larvae prefer feeding on roots of turfgrasses, young ornamental trees and shrubs
• adults have chewing mouthparts, leaving skeletonized leaves, and chew holes in flower buds, fruits and stems
• larvae chew on roots, leaving turf yellow and brown

Biology, Life Cycle & Damaging Life Stage

• overwinter as late-stage larvae in the soil
• pupate in the spring
• adults emerge late spring into summer
• females deposit eggs in soil around larval host plants
• one generation per year
• adult and larval stages are damaging

IPM Recommendations

• Japanese beetles are invasive pests and are not established in Utah. Report sightings of this insect the Utah Plant Pest Diagnostic Lab or the Utah Department of Agriculture and Food.
• Maintain healthy plants through proper cultural practices.
• Apply a preventive insecticide (anthranilic diamide; neonicotinoid) to suppress populations.