Japanese Beetles
Pest · Commonly affects: Roses, Grapes, Raspberries, Green beans, Sweet corn, Apple trees
Japanese beetles (Popillia japonica) are an invasive scarab beetle introduced from Japan that is now widespread across the eastern and midwestern United States and slowly expanding westward. They matter to home gardeners because the adults feed in swarms on hundreds of plant species while their larvae chew turf roots, making them one of the most damaging summer pests in many regions.
How to identify it
Adult beetles are about a third to a half inch long with a shiny metallic green head and thorax and coppery-bronze wing covers. The surest way to tell them apart from lookalike native beetles is the row of five small white tufts of hair along each side of the abdomen, plus a pair of tufts at the tip. The larvae are plump, C-shaped white grubs with tan-brown heads that live in the soil beneath lawns.
Damage
Adults chew out the soft tissue between leaf veins, leaving a lacy, skeletonized look, and they also disfigure flowers and gouge ripening fruit. The soil-dwelling grubs feed on grass roots, producing brown, wilting patches of turf that can be lifted up like loose carpet.
Prevention
Favor plants that beetles usually ignore, such as boxwood, lilac, and most conifers, and place highly attractive plants like roses and grapes where you can watch them daily. Keep plants vigorous with even watering, good spacing, and healthy soil so they recover faster from feeding, and avoid keeping lawns soggy in midsummer, since consistently moist soil draws egg-laying females and helps grubs survive. Practicing good sanitation by promptly picking up fallen, overripe, or damaged fruit removes odors that lure in still more beetles.
How to manage it
The most dependable home tactic is handpicking: in the cool early morning hold a container of soapy water under a cluster and tap the plant, since disturbed beetles reflexively drop and fall in. Shield young or high-value plants with lightweight floating row covers or fine mesh netting through the few weeks of peak adult flight, uncovering anything that needs pollinators while it blooms. Prune out and discard heavily chewed tissue, water evenly to keep plants stress-free, and welcome natural allies such as birds, predatory ground beetles, and parasitic wasps and flies; note that store-bought pheromone traps tend to pull in more beetles than they capture and are best left out of the garden.
General guidance for US home gardens, focused on prevention and non-chemical control. For a confirmed diagnosis and options specific to your area, contact your local Cooperative Extension office. Page updated Aug 4, 2026.