May/June Beetles

Pest Description

• adults: 1/2 – 1 inch long and vary in color from light to dark brown to reddish brown
• larvae: 1/8 – 1 inch long; c-shaped; cream colored; grayish rear end; yellow-brown head with three pairs of legs

Host Plants, Diet & Damage

• adults feed on foliage of broadleaf plants and conifers
• larvae feed on the roots of grasses, trees and shrubs
• larvae chew on roots, leaving turf yellow and brown
• severe root damage leaves turf with a spongy feel and turf that peels away easily from soil when tugged
• secondary damage can occur when animals, such as birds, dig up turf in search of white grubs
• adult damage is seen as holes in foliage

Biology, Life Cycle & Damaging Life Stage

• overwinter as mid- to late-stage larvae in the soil or as newly emerged
• adults that remain in the soil until spring
• adults emerge late spring into summer to feed and mate, and deposit spherical, white eggs in the soil
• larvae initially feed on organic matter before feeding on roots; second year larvae cause most damage
• larvae move deeper in the soil in the fall to hibernate
• some species have a 2 to 3-year life cycle
• larval stages are damaging to turf

IPM Recommendations

• Maintain healthy plants using proper cultural practices.
• Monitor by sampling soil to search for larval stages.
• Apply a biopesticide containing entomopathogenic nematodes or Beauveria fungal spores for suppression.
• Apply a preventive insecticide (neonicotinoid; anthranilic diamide) in spring.