California is home to several beetles commonly called June bugs, but the two you’re most likely to encounter are the Ten-lined June beetle and the Figeater beetle (also known as the green fruit beetle). Both are large, noisy, and show up in summer, but they look and behave quite differently. Here’s what you need to know about each one.
The Two Most Common June Bugs in California
The Figeater beetle is the iridescent green one you’ll see bumbling through your yard or bouncing off walls in summer. Adults are 3/4 to 1-1/3 inches long, metallic green on top with brown or tan edges along the wing covers, and have a small horn-like projection on the face. They’re clumsy fliers, often compared to tiny drunk helicopters, and they’re attracted to ripe fruit, compost piles, and anything fermenting. If you’ve ever had one crash into you at a backyard barbecue, it was almost certainly a Figeater.
The Ten-lined June beetle is the brown-and-white striped one that smacks into your porch light at night. It’s roughly the same size as a Figeater but stockier, with distinctive white stripes running lengthwise down its back. Males are strongly attracted to light sources and typically start showing up in early June, continuing through September. Pick one up and it will produce a surprisingly loud hissing or squeaking sound by forcing air through its wings. It’s harmless, just startling.
Southern California also has a third species worth mentioning: the eastern green June beetle, which is virtually identical to the Figeater but slightly smaller (3/5 to 9/10 inch long) and more variable in color. The two are so similar that even experts sometimes need dissection to tell them apart, so for practical purposes you can treat them as the same beetle.
When and Why They Show Up
June bugs earn their name honestly. Adults emerge from the soil starting in late June and remain active through September, depending on the species and your local climate. The Ten-lined June beetle has a two-year life cycle entirely underground before the adult finally surfaces. During those two years, the larva (a white, C-shaped grub) feeds on roots and organic matter in the soil, molting through three stages. It overwinters twice, pupates in late spring of the second year, and then emerges as the beetle you see at your porch light.
Figeater beetles follow a similar underground pattern, with grubs developing in compost, mulch, and rich soil before emerging as adults. You’ll notice them most in areas with fruit trees, vegetable gardens, or compost bins, since the adults feed on soft, ripe fruit like figs, peaches, and tomatoes.
Grub Damage to Lawns and Gardens
The adults are mostly harmless to your landscape (Figeaters can damage ripening fruit, but that’s about it). The real concern is underground. June beetle grubs feed on live roots and organic matter in the top several inches of soil, with larger grubs tunneling as deep as 8 inches or more. This root feeding and burrowing loosens soil and thins out the thatch layer at the base of your grass.
Damage tends to be most noticeable in late summer, when root loss from grub feeding overlaps with heat stress and drier conditions. You’ll see the lawn take on a dull color and start to wilt. Affected areas feel spongy underfoot, and badly damaged turf can be peeled right off the soil surface like a carpet. Larger grubs also push loose soil up through their tunnels, creating small mounds that look like earthworm castings, especially after heavy rain.
The secondary damage can be worse than the grubs themselves. Skunks, raccoons, and other animals dig through lawns to eat grubs, tearing up patches of turf and leaving depressions across the yard. If you’re finding torn-up lawn sections alongside the spongy, wilting areas, animals hunting grubs are the likely cause.
Kentucky bluegrass, perennial ryegrass, and creeping red fescue lawns are the most vulnerable. If you have tall fescue, bermudagrass, or zoysia, grubs rarely cause noticeable problems.
Managing June Bug Grubs
Before reaching for any product, check whether you actually have a grub problem worth treating. Dig up a square foot of turf in an affected area and count the grubs. Five or fewer per square foot is a normal population that doesn’t need intervention.
If the count is higher, the most effective non-chemical option is beneficial nematodes, microscopic worm-like organisms that attack grubs in the soil. Apply them early in the season when grubs are small and actively feeding near the surface. The soil needs to be warm (at least 60°F) and moist but not waterlogged. Water the lawn before and after application, and keep the soil moist for the two weeks following. A second application about two weeks after the first improves the chances that nematodes establish and provide lasting control. Different nematode species target different pests, so check the product label to make sure you’re buying the right one for scarab beetle grubs.
Cultural practices matter just as much. Growing the right grass species for your climate zone, maintaining proper irrigation, fertilizing appropriately, and managing thatch buildup all help your lawn withstand some grub feeding without showing damage. A healthy lawn can tolerate a moderate grub population that would devastate a stressed one.
Dealing With Adult Beetles
Ten-lined June beetles are drawn to tungsten and other warm-toned outdoor lights. If they’re swarming your patio every evening, switching to yellow “bug lights” or cooler LED bulbs reduces the attraction significantly. They’re not harmful to people, pets, or plants in their adult stage, so the main issue is just the nuisance of large beetles crashing into things (and the startling hiss when you accidentally grab one).
Figeater beetles are trickier because they’re after your fruit, not your lights. Harvesting fruit as soon as it ripens, removing fallen fruit from the ground, and covering compost bins can reduce their numbers in your yard. Some gardeners use fruit-baited traps to catch adults, though this works better for small infestations than large ones. Since Figeater grubs develop in compost and organic matter rather than lawn roots, turning and managing compost piles can disrupt their life cycle before they ever become adults.