IDENTIFICATION — If these pests weren’t so destructive, they’d be pretty. Shiny bronze-green adults are about 3/8 in. long. Larvae are 1-1/4-in.-long, C-shaped white grubs. These beetles are found in the eastern third of the United States and parts of Ontario and Quebec. They sometimes show up on nursery plants in the West, but they aren’t a common pest there yet.
DAMAGE — Adults feed on most plants, boring into flowers or fruit and skeletonizing leaves. Grubs eat grass roots, causing spongy, off-color patches in lawns.
CONTROL — If you see just a few, pick them from plants in early morning or late evening when they’re less active. A big infestation may need a general-purpose pesticide, but be sure it’s safe for the plant. Don’t use traps — they just attract more beetles. To control the grubs, try bacterial milky spore disease or parasitic nematodes (Heterorhabditis), which you can find at Gardens Alive! Both are watered into the lawn.