Are June Beetles Harmful? Uncovering the Truth Behind These Bugs

June beetles are a common sight in North America during the warm summer months.

With their distinctive metallic green color and buzzing flight pattern, they often capture the attention of gardeners and nature enthusiasts alike.

The outer edges of the body exhibit colors ranging from bronze to yellow, while the wing covers occasionally take on a reddish-brown tint.

Are June Beetles Harmful

But the question arises, are they harmful?

The answer to this question largely depends on the stage of a June beetle’s life cycle. In this article, we are going to explore this impact in details.

Are June Beetles Harmful?

Adult June beetles, such as the Green June Beetle, are typically harmless and feed on fruits, nectar, and foliage.

They may cause minor damage to plants, but are generally considered non-threatening to gardeners. However, adults may inflict your ornamental plants with foliar damage.

However, it’s the June beetle larvae, also known as white grubs, that can cause considerable damage to the roots of grass, broadleaf weeds, trees, and shrubs.

In some cases, these grubs require 2 or 3 years in the soil to fully develop, gradually causing more extensive harm to plants as they grow.

To keep your plants healthy and free from damage, it’s essential to stay vigilant and manage such pests effectively.

June Beetles: Life Cycle, Species, and Habitat

Life Cycle

June beetles complete their life cycle in 2-3 years2. The different stages of their life cycle include:

  • Eggs: Female beetles lay eggs in the soil.
  • Larvae (grubs): Feed on roots; grow from 1/4 inch to 2 inches long1.
  • Pupae: Brown and 1/2 inch long1.
  • Adults: Metallic green or brown; nearly 1 inch long1.

June Beetle Species

Some common June beetle species include:

  • Green June Beetle (Cotinus nitida)1
  • May Beetle (Phyllophaga spp.)3
  • May Bug (European Chafer, Amphimallon solstitiale)

Geographical Distribution

June beetles are commonly found in:

  • North America1
  • Europe (May Bug)

They are attracted to light and have six legs3. June beetles can be a food source for birds and other animals.

However, their larvae/grubs can damage plant roots2. They can be a nuisance for gardeners and homeowners

Comparison Table: Green June Beetle vs. May Beetle

FeatureGreen June BeetleMay Beetle
Adult colorMetallic green with bronze edgesLight tan to reddish-brown
Larval appearanceCream-coloredCream-colored
Time to complete life cycle2-3 years2-3 years

The Harmful Impact of June Beetles

Damage to Plants and Gardens

June beetles can cause significant damage to plants and gardens. They feed on the leaves of various plants, such as roses and other flowers. This can lead to:

  • Stunted plant growth
  • Reduced flowering
  • Increased susceptibility to diseases

Effects on Lawns and Yards

June beetles also impact turfgrass, commonly found in lawns and yards. Their grubs feed on the roots of grasses, which can cause:

  • Patches of dying or dead grass
  • Loose turf that is easily pulled up
  • Uneven lawn surfaces

A well-manicured lawn might suddenly show signs of infestation, such as brown patches or dead grass due to June beetle infestation.

Underground Impact

The underground impact of June beetles is mainly caused by their larvae, or grubs. These grubs feed on various plant roots and can cause significant soil issues, such as:

  • Compromised soil structure
  • Decreased nutrient availability for plants
  • Increased erosion risk

Grubs can grow up to 2 inches long, making them quite damaging to plant roots and soil.

Impact on Trees and Shrubs

June beetles may be particularly harmful to trees and shrubs in gardens and landscapes. They can cause:

  • Defoliation of leaves
  • Weakened branches
  • Slow tree and shrub growth

Crops like corn may also suffer from June beetle infestations, and their feeding can lead to crop loss or poor yield.

Examples of Damage Caused by June Beetles

Area of ImpactExamples of Damage
PlantsStunted growth, reduced flowering
LawnsDead grass, loosened turf
SoilCompromised nutrient availability
Trees & ShrubsDefoliation, weakened tree structure

While June beetles can be quite damaging, understanding their impact on various aspects of gardens and landscapes can help in their monitoring and control.

How to Manage June Beetle Infestations?

Cultural Controls

  • Hand-picking: Remove adult beetles and larvae by hand, especially during dusk when they are most active1.
  • Trapping: Attract beetles with light traps or fruit-based traps2. Dispose of trapped beetles daily.

Biological Controls

  • Predators: Birds, toads, snakes, moles, and skunks can help control beetle populations by feeding on larvae and adult beetles4.
  • Nematodes: Introduce beneficial nematodes (Heterorhabditis bacteriophora) to target the white grub stage of the life cycle5.

Chemical Controls

  • Insecticides: Apply insecticides with active ingredients such as carbaryl or trichlorfon when grubs are feeding3.
  • Preventatives: Use products containing imidacloprid or halofenozide to prevent beetle infestations6.

June beetle control measures

MethodProsCons
CulturalNon-toxic, minimal environmental impactCan be labor-intensive
BiologicalNatural, minimal chemical useSlow-acting, predators can be unreliable
ChemicalFast-acting, effectiveCan harm non-target organisms, potential health risks

Note: Always consider the potential impact on pets and human health before using chemical controls.

Prevention Strategies and Tips

Lawn Care

A healthy, well-tended lawn can resist June beetles and their larvae. Follow these guidelines to ensure better lawn care:

  • Regularly water your lawn, especially during dry spells.
  • Mow at the appropriate height for your grass type to promote healthy growth.
  • Fertilize with the right nutrients and amounts for your turfgrass species.

Garden Maintenance

Prevent damage to your plants by following these steps:

  • Regularly inspect plants for beetles and their larvae, removing them by hand if necessary.
  • Keep your garden free of debris, which can provide shelter for beetles.
  • Plant beetle-resistant plants with strong odors like marigolds and garlic

Monitoring and Trapping Methods

To monitor and trap June bugs, consider these methods:

  • Commercial beetle traps can be used to control adult beetles.
  • Hand-pick beetles off plants and drop them into a bucket of soapy water.
  • Make a homemade June bug trap with molasses and water.

June beetle trapping methods

MethodProsCons
Commercial beetle trapsEffective, easy to useCan be expensive, may attract more beetles
Hand-pickingChemical-free, inexpensiveTime-consuming, not suitable for large areas
Homemade June bug trap with molasses and waterInexpensive, eco-friendlyLess effective than commercial traps

Remember to always practice moderation when using pesticides, as excessive use can harm your garden’s health and the environment.

Organic options like milky spore can also help control grub populations.

Conclusion

While June beetles look captivating with their metallic green color during North America’s warm summer months, their impact on gardens and landscapes is not to be underestimated.

Adult beetles primarily feed harmlessly on fruits, nectar, and foliage. However, it’s the white grubs, the beetle larvae, that can cause extensive damage to plant roots and soil health.

Vigilance, along with a balanced approach of cultural, biological, and chemical controls, proves essential in maintaining healthy plants and landscapes, ultimately mitigating the potential harmful effects of June Beetles.

Footnotes

  1. NC State Extension Publications 2 3 4 5 6
  2. Integrated Pest Management 2 3
  3. University of Maine Cooperative Extension 2 3
  4. Illinois Extension | UIUC 2
  5. Japanese Beetle: Tips for Your Lawn – MSU Extension
  6. Japanese Beetle: Tips for Your Lawn – MSU Extension

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about June Beetles. Scroll down to have a look at some of them.

Letter 1 – June Beetle from Turkey

Brown bug with white spots
Location: Marmaris, Turkey (south-west)
July 17, 2011 3:51 am
Hello Bugman,
She has long antennas with wing covers. Hard body, brown with white spots on her. She weeeeks when touched. Otherwise she is quite quiet.
Size: as big as a small finger
Thank you so much,
Signature: don’t mind.

June Beetle: Polyphylla fullo

Dear don’t mind,
Your June Beetle is
Polyphylla fullo, and she is a he based on the antennae.  The male has much grander antennae which he uses to locate the female.  You can see a similar photo on BioLib.

June Beetle

Letter 2 – Lined June Beetle

Subject: What pretty eyelashes you have…
Location: Aurora, CO
July 18, 2013 10:45 pm
Hello,
My husband spotted this beauty on the side of our house this evening. I’ve looked up several feather-horned beetles, but can’t find one quite like this one. Would you have any ideas?
Signature: Intrigued in CO

Lined June Beetle
Lined June Beetle

Dear Intrigued in CO,
This is a Lined June Beetle in the genus
Polyphylla.  We are not certain if it is our Bug of the Month, the Ten Lined June Beetle, or a closely related species.  Your individual is a male and he uses those highly developed antennae, which do resemble eyelashes, to locate females by sensing their pheromones.

Letter 3 – Lined June Beetle

Subject:  Hissing beetle in NC in July
Geographic location of the bug:  NC mountains, Lake Toxaway
Date: 07/14/2018
Time: 03:46 PM EDT
Your letter to the bugman:  I thought this was a ten lined june bug, but they’re apparently only found out west.  I’m in NC.  It hisses, so what is it?
How you want your letter signed:  Chris

Lined June Beetle

Dear Chris,
You are absolutely correct that this is not a Ten Lined June Beetle,
Polyphylla decemlineata, a western species, however it is still a Lined June Beetle in the genus Polyphylla.  The large antennae indicates it is a male.  The hissing sound you heard is made when the beetle rubs its body parts together, a process known as stridulation. 

We believe your individual is a species with a BugGuide range of “Virginia south through the Great Smokies to Louisiana” and with no common name other than the general genus name of Lined June Beetle, Polyphylla comes, based on this BugGuide image, but we would not rule out that it might be the Variegated June Beetle, Polyphylla variolosa, based on this BugGuide image.  Both species are in your geographic area.  Apparently these species can be difficult to differentiate, as this BugGuide posting proves.

Letter 4 – June Beetle Pupae

what’s that bug?
these baby bugs were found underground in nothern Arizona. there were ten lined june bug larva near the same area. we have some kind of red june bettles around that look alot like these. perhaps that is what they are? (I sent you the same photo before but I can’t find it on your site, so here it is again)
D. Pipkin

Hi D.,
These are Scarab Beetle Pupae, and the Red June Beetles you mention are a very likely candidate.

Letter 5 – Hammond’s Lined June Beetle

Subject: Screeching, furry, brown beetle(?)
Location: Northeast Iowa
July 7, 2016 11:34 pm
Hi! My fiancé and I heard a loud winged buzzing in our front window- sounded just like a large wasp- and our cat caught this guy. When my fiancé picked it up in a napkin to release/inspect it is made a screeching sound- almost like it was spitting a liquid against the napkin but it wasn’t. We put it in a ventilated jar to check it out and try to research it, which brought me to this site. I’m very curious if you all have any ideas?

I’m in Salix northeastern corner), Iowa. It’s early July. It is medium brown colored, hard shell wings but then under them are wings that look very similar to a wasp. It has a furry chest and butt area, looks slightly stripped on there too. Almost looks like the butt ends in a stinger, but can’t tell. The antenna have a fan-like quality.

The screeching/spitting/screaming sound was pretty loud when it made it but it didn’t replicate it in the jar. Thanks so much for the help! Also this was very late at night- around 11pm.
Signature: M and J

Lined June Beetles
Hammond’s Lined June Beetles

Dear M and J,
Though its markings are much more subtle than the Ten Lined June Beetle, your Scarab is nonetheless a member of the Lined June Beetle genu
s Polyphylla.  We believe we have correctly identified it as a male Hammond’s Lined June Beetle, Polyphylla hammondi, thanks to images on BugGuide

Males in the genus have fanlike, or more correctly “flabellate” according to BugGuide, antennae.  According to BugGuide it is:  “widespread in w. US, with isolated populations east of the Mississippi River.”  The “screeching sound” you describe is made by rubbing body parts together and it known as stridulation.  Many beetles will stridulate when handled.

Letter 6 – June Beetle

Hello,
Any idea what bug this is? I found it flying outside near the top of my birch tree.
Thank you
Hal

Hi Hal,
You have a species of June Beetle. Your photo isn’t the best quality and it is difficult to tell if the color is really golden or if it is a reflection from your flash.

Letter 7 – June Beetle

Subject: Unknown beetle
Location: Toronto, Ontario, Canada
June 2, 2014 6:11 pm
I found this beetle crawling up the wall towards my porch light, I think it in the Genus Dichelonyx. I would love to know what species it is and any info you may have.
Signature: Gary Yankech

June Beetle
June Beetle

Dear Gary,
We believe you have correctly identified this June Beetle as a member of the genus
Dichelonyx based on this and other images posted to BugGuide.  We also received several other inquiries from you, and we want to thank you for using a separate form for each submission. 

Alas, we are not entomologists and we do not have any formal training in entomology, so we are not really qualified to attempt a species identification for you, but perhaps one of our readers will be able to provide you with more specific information.

Letter 8 – June Beetle from China

Blue-Eyed Golden June Bug
March 24, 2010
I sent you some photos of this odd looking Chinese insect a few days ago. Did you get them? I swear, it’s not a Photoshop job.

It has eyes like Paul Newman and more gold leaf than a temple. What is this thing? I have dozens more photos. Let me know if you want them. Thanks!
Mike J.
Dongguan, China

Unknown June Beetle

Dear Mike,
We did not see your earlier submission.  We are not certain of the species, but we will post your June Beetle in the hopes that one of our readers can make an identification.

Hi Daniel,
Thanks for your reply. Here are the shots I originally submitted and the corresponding text.
Hope you can figure it out. There are lots of these guys flying around here in the evening; similar to Junebugs back in the US midwest.
Mike

Beetles in China
I see these frequently in South China. They fly in the evening like June Bugs. The golden shell, big blue eyes and fern-like feelers are pretty cool. This guy found his way inside tonight. Wouldn’t let him leave without some photos. Thought you’d enjoy these.
Mike J.
Dongguan, China

Unknown June Beetle

Letter 9 – June Beetle from the Netherlands

unidentified beetle
Location: Wassenaar, Zuid Holland, Netherlands
July 4, 2011 12:44 pm
I took this photo outside my front garden. I live in south Holland, Netherlands, Europe.
When I poked it gently with my door key it made a noise, I think coming from its rear but not sure.
It was not interested in moving and I found it again trying to dig into the dry dirt. It was about 3.5 – 4 centimetres long.
Signature: Rosie

June Beetle

Hi Rosie,
This is sure a pretty Scarab Beetle, actually one of the June Beetles.  We located it on the Photo Gallery of Beetles website, and had to view all the thumbnails, where we learned it is
Polyphylla fullo.  There are some nice photos here, and BioLib also has a good photo.  According to the Free Dictionary:  “The beetle is distributed in middle and southeastern Europe; in the USSR it is found in Byelorussia, the Ukraine, and the Volga Region. The beetles fly in July evenings and nights; they feed on the leaves and needles of trees.

The females deposit their eggs in the soil. Development continues for three years; in extremely dark places, development may take up to four years. Young larvae feed on humus and the roots of herbaceous plants; older larvae gnaw through the roots of shrubs and trees and cause desiccation of the plants.”

Letter 10 – june beetle infestation

Hello,
Here’s a picture of one of our trees in central NM that is covered with these beetles. I think they are June bugs comparing them to a picture ;on your site. For 3 nights we have been swatting the bugs inside and just noticed tonight that all our pine trees are completely covered with these guys chewing the needles.

Do you have any suggestions on how to get rid of them? We had lots of birds here but none now that the bugs are here. Much appreciate your speedy reply.
Sally Beers

Hi Sally,
It is dificult to tell exactly, but your photo does seem to indicate a June Beetle infestation.. As you must realize, they are very fond of eating pine needles. Sorry, we have no erradication advice. You could try trapping them at night when they are attracted to lights.

Daniel,
Thanks for getting back so quick. If you are interested, here’s what we did:
At night while all the beetles were munching away we shook the tree and gathered them in a tarp. When the sun came up they dropped from the trees and began crawling to our house.

Sprayed a bit on the edges of the entry way and swept a lot up. Guess they are eating by night and sleeping in our walls by day. Today will go for bug zappers to try and get some more. Thanks so much for your help.
Sally

Letter 11 – Lined June Beetle

large striped beetle
Tue, Jun 9, 2009 at 11:17 AM
this beetle, probably a bit more than two or three inches was in our garage. He was struggling on his back. When I tried to turn him over, he hissed at me. I finally picked him up and put him out in the front yard. Can you tell me what he is?
Linda Williams
Marble Falls, Texas

Lined June Beetle
Lined June Beetle

Hi Linda,
This is one of the Lined June Beetles in the genus Polyphylla, probably Polyphylla occidentalis, though s
pecies identification may be difficult.  There are numerous matching images posted to BugGuide.

  The genus page on BugGuide indicates:  “Food Adults feed on tree foliage, thus sometimes called ‘chafers’.
Life Cycle Eggs are laid on soil near host plants. Larvae hatch, burrow down and feed on roots of shrubs, trees, require 2-3 years to reach maturity. Pupation is in underground chambers. Adults come to lights. ”  These beetles make squeaking noises when handled.

Letter 12 – Lined June Beetle

Strange looking beetle
July 14, 2009
I have lived in Oklahoma all my life and have never seen one of these bugs in my 30 years in this state. They are about and inch and half long with a striped abdomen. They hiss quite loudly when disturbed. And the antler like formations on the head are very interesting. Is this a native species to Oklahoma.
David Gerlach
Oklahoma City, Ok. USA

Lined June Beetle
Lined June Beetle

Hi David,
This is one of the Lined June Beetles, probably Polyphylla occidentalis.  You can see some matching images on BugGuide.
He has some pretty impressive antennae.

Letter 13 – Lined June Beetle

Beetle
Location:  Socorro, NM, USA
July 19, 2010 8:30 am
I encountered this fair-sized beetle on our door upon taking out some trash. It was kind enough to stay put as I ran and grabbed the camera. Sorry for the relatively poor quality; it was dark and my camera has a tendency to over-saturate with the flash. It was a little over an inch long, by my estimation.
Grady Owens

Lined June Beetle

Hi Grady,
As you indicated, your photo is not ideal quality, however, we are confident that this is a Lined June Beetle in the genus
Polyphylla.  We cannot, however, commit to an exact species identification.  Perhaps it is Polyphylla hirsuta, a species that BugGuide reports from nearby Arizona.

Letter 14 – Lined June Beetle

Subject: Large striped beetle in Montana
Location: NW Montana, USA
July 17, 2017 12:15 pm
Found two of these large (a little more than an inch long) striped beetles at a service station in the Flathead Valley near larch and pine forest in NW Montana. Probably drawn in by lights the night before. Can you help me ID?
Signature: Dorinda Troutman

LIned June Beetle

Dear Dorinda,
This is a Lined June Beetle in the genus
Polyphylla, but we are not comfortable providing a species name as there are many similar looking members of the genus, and BugGuide, our favorite source for North American identifications, is currently unavailable.

Daniel:
I very much appreciate your prompt reply with an answer. My husband told me it was a June beetle when I showed him the photo yesterday, and I had seen somewhat similar ones, but not exactly the same, on your website. My beetle did not show antennae and its head and body were two different colors. I’m happy with the general name.
Thank you again,
Dorinda Troutman

Letter 15 – Lined June Beetle

Subject:  What kind of moth is this?
Geographic location of the bug:  Sylmar, California
Date: 10/02/2017
Time: 10:15 PM EDT
What kind of moth is this? I really want to know. Thank you.
How you want your letter signed:  Anywhere

Lined June Beetle

Dear Anywhere,
This is not a moth.  It is a Lined June Beetle in the genus
Polyphylla, most likely the Ten Lined June Beetle, a common species found during the summer in Southern California.  This is late in the season for a sighting.  BugGuide does include September sightings in both Arizona and California, but there are no reported October sightings.

Authors

  • Daniel Marlos

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

11 thoughts on “Are June Beetles Harmful? Uncovering the Truth Behind These Bugs”

  1. As often happens, I don’t know the species, but I can declare that this one would look quite tasty to much of the world, especially in Asia. Species in Melolonthinae are enjoyed in many parts of the world; the great Vincent Holt wrote about them in his landmark 1885 book “Why Not Eat Insects?”

    There’s also some fascinating documentation of grubs and eggs harvested in Indiana in the early 1900s and served to the leadership of the Department of Agriculture. I can provide the text if anyone’s interested. Alternately, I’d love to find out how to harvest these insects efficiently.

    Dave
    http://www.smallstockfoods.com

    Reply
  2. Given that Holt, way back in 1885, wrote about the edibility of cockchafers, which are quite similar to this specimen, I’d definitely consider this an amusing appetizer were I in the right mood.
    Scarabidae can be eaten in all the phases of their life-cycle.

    Dave
    http://www.smallstockfoods.com

    Reply
  3. I live in east Vancouver and for the last few nights at dusk there are bugs that are buzzing around my front porch and outside in all the trees that line the street. They look to be the size of a small bumble bee and they make a buzzing sound. I’m almost certain that they are not bumble bees but can’t figure out what they may be. Any thoughts to what they might be?

    Reply
  4. My son just found one sleeping on our porch with
    a pile of lil moths early this morning! I’ve never seen a junebug before so we went down the google rabbit hole! We’re in eastern washington. Though the same as this image otherwise, it doesn’t have the hand-tennas. Must be female?

    Reply
  5. My son just found one sleeping on our porch with
    a pile of lil moths early this morning! I’ve never seen a junebug before so we went down the google rabbit hole! We’re in eastern washington. Though the same as this image otherwise, it doesn’t have the hand-tennas. Must be female?

    Reply
  6. Hello! I am developing a life cycle diagram to support a status assessment for the U.S. Fish and Wildlife Service for Casey’s June beetle (Dinacoma caseyi). I would like to ask your permission to use the Scarab beetle pupae from this page, potential red june beetle from Arizona. We have not observed D. caseyi pupae and the figure would indicate that this is a generalized scarb pupae. I appreciate your consideration. Please reach out if you have questions. Thank you!

    Reply

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