June bugs are beetles. Specifically, they belong to the scarab beetle family, which makes the comparison less “versus” and more “subset of.” The confusion is understandable, though, because “beetle” covers an enormous group of insects (over 400,000 species), and June bugs have enough distinctive traits that many people think of them as something separate. Here’s what actually sets June bugs apart from the broader beetle world and from the look-alikes people commonly confuse them with.
Why June Bugs Are Beetles
All June bugs belong to the order Coleoptera, which is the scientific grouping that contains every beetle on the planet. Within that massive order, June bugs sit in the scarab family. The most common June bugs in North America belong to the genus Phyllophaga, which includes nearly 300 species. The green June beetle and the ten-lined June beetle belong to different genera but are still scarabs.
What makes a beetle a beetle is its pair of hardened front wings, called elytra, that fold over the back like a protective shell. June bugs have these. They also have chewing mouthparts and undergo complete metamorphosis (egg, larva, pupa, adult), both hallmarks of beetles. So when you see a June bug clinging to your screen door on a warm night, you’re looking at a beetle with a common name.
How June Bugs Look Compared to Other Beetles
Adult June bugs are half an inch to one inch long with thick, oval bodies. Most are brown, ranging from reddish-brown to nearly black, though the green June beetle has a metallic green or coppery-green color. Their legs are thin and jointed, which is why they latch onto screens and clothing so easily. They have fan-shaped antennae that they can spread open, a feature shared by other scarabs but not by many beetle families.
In their larval stage, June bugs are white grubs: C-shaped, white-bodied, with brown heads and six small legs clustered near the head. They range from 3/4 inch to nearly 2 inches long. If you dig one up and flip it over, you can identify it as a June bug grub by looking at the last body segment, where two rows of tiny spines run parallel like railroad tracks. Other beetle grubs lack this specific pattern.
June Bugs vs. Japanese Beetles
This is the comparison most people are actually trying to make. Japanese beetles and June bugs are both scarabs, they both show up in early summer, and their grubs both destroy lawns. But they’re easy to tell apart once you know what to look for.
Green June beetles are about an inch long. Japanese beetles are roughly half that size, sometimes even a third as large. Japanese beetles also have small but obvious white tufts of hair poking out from under their wing covers along both sides of the abdomen. Their coloring is distinctive too: a metallic green head and thorax with coppery-brown wings. June bugs are more uniformly colored, either solid brown or solid green depending on the species, and more tapered toward the head.
Their feeding habits differ significantly. Japanese beetles are agricultural pests that chew through corn silks, soybean leaves, rose petals, and hundreds of other plants. Green June beetles mostly stick to nectar from flowering trees and bushes near where they grew up as grubs. If something is skeletonizing your rose bushes, you’re almost certainly dealing with Japanese beetles, not June bugs.
The June Bug Life Cycle
June bugs have a surprisingly long development period. Most species in North America take three full years to go from egg to adult. Adults emerge in late May and early June, fly around at night (crashing into porch lights along the way), mate, and then females burrow into the soil to lay eggs. After hatching, the grubs spend the next two years underground feeding on plant roots, passing through three growth stages and getting larger and more destructive with each one. In late summer of their third year, they pupate in the soil. Adults emerge the following spring to start the cycle over.
One species, Phyllophaga tristis, completes the cycle in two years instead of three. But either way, the vast majority of a June bug’s life is spent as an underground grub, not as the bumbling adult that bonks into your windows.
Lawn Damage From June Bug Grubs
The real problem with June bugs isn’t the adults. It’s the grubs. They feed on the roots of both warm-season and cool-season turfgrasses, including bermudagrass, fescues, bluegrass, and St. Augustinegrass. The third and largest growth stage does most of the visible damage.
Grub damage shows up as irregular patches of dead grass that look a lot like drought stress. The giveaway is that damaged turf pulls up easily because the roots are gone. In severe cases, you can roll the grass back like a carpet. A general threshold for treatment is 5 to 10 grubs per square foot. Below that, a healthy lawn can usually tolerate the root loss.
There’s also secondary damage to deal with. Skunks, raccoons, and armadillos will tear up a lawn to get at the grubs, sometimes causing more visible destruction than the grubs themselves.
Managing June Bug Grubs
Timing matters more than product choice. Grubs are most vulnerable right after eggs hatch, when they’re small and close to the soil surface. The two most common preventive treatments are long-lasting insecticides applied around the time eggs are laid, so the chemical is already in the soil when larvae emerge. For lawns already showing damage, a fast-acting rescue treatment can move quickly into the soil and kill actively feeding grubs within days.
For a biological approach, parasitic nematodes in the genus Heterorhabditis can be mixed with water and drenched into the soil. They infect grubs, which turn reddish-brown and die within a few days. The soil needs to be at least 50°F for the nematodes to work. Another biological option, milky spore disease, only affects Japanese beetle grubs and won’t control June bug species. It also works slowly, typically infecting just 2 to 5 percent of the Japanese beetle grub population per year, so it’s a long-term suppression tool rather than a quick fix.
Two simple lawn care practices also help. Mowing at a higher setting encourages deeper root systems that tolerate more grub feeding. And allowing the lawn to dry out periodically between waterings kills eggs and young grubs, which are sensitive to dry soil conditions.
Are June Bugs Harmful to People or Pets?
June bugs don’t bite, don’t sting, and aren’t toxic. They’re clumsy fliers that crash into things, cling to your clothes, and generally create more startlement than harm. If your dog eats one (and dogs often do), it’s not a concern. The adults are a nuisance around outdoor lighting but pose no health risk. The grubs are strictly a lawn and garden problem.