You hear that clumsy thwack against your window screen on a humid evening. It’s loud. It’s frantic. It’s a June bug. These heavy-bodied, reddish-brown beetles (usually from the genus Phyllophaga) are basically the bumbling idiots of the insect world. They fly like they’ve had one too many, crashing into porch lights and getting tangled in your hair. But while they seem harmlessly annoying when they’re buzzing around your head, they’re actually busy fueling up. If you’ve ever looked at a brown patch in your lawn or noticed jagged holes in your favorite oak tree, you've probably wondered: what does june bugs eat exactly?
The answer changes depending on who you’re talking about—the clumsy adult or the ravenous teenager living underground.
The Two-Stage Diet: From Soil to Sky
To understand their diet, you have to realize that a June bug is basically two different animals throughout its life. Most of their lives are spent in the dirt. As larvae, they are known as "white grubs." These are those C-shaped, squishy white things you find when you’re digging in the garden. They are pure eating machines. They don't have wings, they don't have eyes to speak of, and they definitely don't care about your curb appeal.
Grubs are the true villains of the story for homeowners. They live underground for one to three years, depending on the specific species and the climate. During this time, they eat one thing: roots. They love the tender roots of cool-season grasses like Kentucky Bluegrass or Fescue. When a local population of grubs gets too high, they can literally detach your lawn from the soil. You could reach down, grab a handful of grass, and peel it back like a piece of old carpet. It's gross. It’s also devastating for a lawn.
But then, they transform.
Once they pupate and emerge as adults in late May or June—hence the name—their palate shifts completely. They move from the basement to the penthouse. Adult June bugs are leaf eaters. They go for the foliage of deciduous trees and shrubs. You’ll find them munching on oaks, walnuts, birches, and even fruit trees like peaches or apples.
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Why your garden looks like Swiss cheese
If you see leaves that look like they’ve been hit by a tiny shotgun, you’re looking at June bug damage. They aren't particularly picky. While they prefer certain hardwoods, they’ll settle for berries or ornamental roses if the "good stuff" isn't around. Honestly, they aren't even great at eating. They’re messy. They nibble edges and create irregular holes, unlike some caterpillars that strip a leaf down to the vein with surgical precision.
Interestingly, some species of June bugs barely eat at all as adults. Their main mission is to find a mate, lay eggs back in the soil, and die. It's a short, frantic life. They are primarily nocturnal, which is why you see them attracted to your lights. The light confuses their internal navigation, leading to those famous "kamikaze" runs into your sliding glass door.
Is your lawn a buffet?
Not every yard is equally tasty to these pests. They have preferences. Grubs thrive in soil that is consistently moist but well-drained. If you over-water your lawn during the heat of the summer, you might accidentally be setting out a "Welcome" mat for mother beetles looking for a place to deposit eggs. They want their babies to have plenty of juicy roots to chew on.
Recent studies from university extension offices, including those at Texas A&M and The Ohio State University, have highlighted that "What does june bugs eat" is often a question of nitrogen levels. High-nitrogen fertilizers can make grass roots more succulent and attractive to larvae. It’s a bit of a Catch-22: you fertilize to make the grass green, but you end up making it a gourmet meal for the grubs.
The predators that eat the eaters
Nature has a way of balancing the books. While June bugs are eating your plants, plenty of things are eating them. For the grubs, skunks and raccoons are the primary threat. If you wake up and find small, conical holes dug all over your lawn, you have a grub problem, and the local wildlife is trying to help you out (while ruining your grass in the process).
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Birds love the adults. Blue jays, crows, and even owls will snatch them right out of the air or off a leaf. Even your dog might try to snack on one. Most vets agree that while June bugs aren't toxic, the crunchy exoskeleton can cause some stomach upset if your pup treats them like popcorn.
Identifying the damage vs. other pests
It’s easy to blame June bugs for everything, but you have to be a bit of a detective.
- Japanese Beetles: These are often confused with June bugs. However, Japanese beetles are active during the day and are much smaller. They "skeletonize" leaves, leaving only the veins behind. June bugs are larger, nocturnal, and leave chunkier, more ragged holes.
- Cicadas: They make a lot of noise, but they don't chew leaves like June bugs. Cicadas feed on plant fluids.
- Fungal Issues: If your grass is turning brown but the roots are still firmly attached to the ground, it’s probably a fungus or drought, not June bug grubs.
You have to do the "tug test." If the grass comes up with zero resistance, you’ve got grubs. If it stays put, look elsewhere for the culprit.
Management and Actionable Steps
Dealing with June bugs is a multi-front war. You have to address the flyers and the crawlers separately. If you’re tired of your garden being an all-you-can-eat buffet, here is how you handle it without nuking your entire ecosystem.
Control the Grubs (The Long Game)
The best time to deal with grubs is in late summer or early fall when the new larvae are small and close to the surface.
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- Milky Spore: This is a natural bacterium (Paenibacillus popilliae) that kills grubs. It’s a long-term solution. It takes a few years to build up in the soil, but once it’s there, it can protect your lawn for a decade.
- Beneficial Nematodes: These are microscopic worms you spray onto your lawn. They hunt down grubs and kill them from the inside. They need moist soil to survive, so timing is everything.
- Aerate your soil: This makes the environment less hospitable for eggs and helps the lawn recover from root damage.
Manage the Adults (The Short Game)
Adult June bugs are harder to control because they fly. You can kill every beetle in your yard today, and twenty more will fly over the fence from your neighbor's house tomorrow.
- Turn off the lights: Since they are attracted to light, keep your outdoor lights off during peak season (June and July) or switch to yellow "bug bulbs" which are less attractive to them.
- Hand-picking: It sounds tedious, but if you have a prized rose bush, going out at night with a flashlight and a bucket of soapy water is effective. Just knock them into the water. They aren't fast.
- Neem Oil: This is a natural deterrent. Spraying it on the leaves of vulnerable trees can make the foliage taste bitter and disrupt the insects' hormones.
Improving Lawn Resilience
A healthy lawn can actually survive a moderate amount of grub feeding. If you keep your grass at a higher height (about 3 to 4 inches), the roots grow deeper and stronger. This makes it harder for grubs to do significant damage. It also shades the soil, making it less attractive to females looking to lay eggs.
Ultimately, June bugs are a natural part of the ecosystem. They provide a massive food source for birds and mammals. While it's annoying to have them "eating" your landscape, a few holes in a maple leaf isn't the end of the world. Understanding their life cycle is the key. You stop asking "what does june bugs eat" and start asking "how do I make my yard less of a target?"
Focus on soil health first. A lawn with diverse microbial life and deep roots can handle a few uninvited guests. If the infestation gets out of hand, choose targeted biological controls over broad-spectrum pesticides to keep the bees and butterflies safe while showing the June bugs the exit.
Next Steps for Success:
Perform a "spade test" by cutting a one-square-foot patch of turf and peeling it back. If you count more than 6 to 10 grubs in that single square foot, it is time to apply beneficial nematodes or milky spore. If you find fewer, your lawn's natural defenses and local predators can likely handle the load without intervention. For adult beetles, prioritize protecting young, vulnerable saplings with neem oil, as established trees can easily withstand the temporary cosmetic damage of a few chewed leaves.