Are Grapevine Beetles Harmful to Humans? Uncovering the Truth

Grapevine beetles are nocturnal insects found in woodlands, thickets, and vineyards, particularly east of the Great Plains.

They have a distinct appearance, with their color varying from pale broom-straw yellow to rich saffron and featured spots on their thorax and elytron.

While these insects are known to populate areas where humans may be active, it’s important to understand their potential impact on us.

Although grapevine beetles may cause concern due to their presence in vineyards and gardens, they do not pose a direct threat to humans. Their primary diet consists of foliage from grapevines or other plants in their habitat.

Thus, their impact on humans is generally limited to potential damage to vegetation, rather than posing a genuine risk for personal harm.

What Are Grapevine Beetles

Identification and Characteristics

Grapevine beetles (Pelidnota punctata) are a type of scarab beetle. They are also known as the spotted June beetle, which belongs to the Scarabaeidae family. They can be found in eastern Canada and some parts of the United States.

These beetles are recognizable by their distinct coloration and physical features:

• Size: Approximately 1 inch in length
• Coloration: Off-yellow to light brown with black spots
• Body: Sturdy and oval-shaped
• Wings: Covered by a hard shell called elytra
• Antennae: Serrated and fan-like
• Mandibles: Strong and developed

Life Cycle

The life cycle of the grapevine beetle consists of four stages: egg, larva, pupa, and adult. The development process is as follows:

1. Egg: Female beetles deposit eggs in the soil near the base of suitable host plants.
2. Larva: The larvae, or grubs, feed on decaying wood and plant material. They grow underground and can stay in this stage for up to two years.
3. Pupa: The mature larvae pupate in earthen cells within the soil.
4. Adult: After approximately 3 to 4 weeks, adult beetles emerge from the pupal stage.

While grapevine beetles primarily feed on grapevines, they do not pose any serious threat to humans.

Grapevine Beetle Interaction With Humans

Biting and Human Safety

Grapevine beetles (Pelidnota punctata) are not harmful to humans. They are not known for biting or displaying any aggressive behavior towards people.

In fact, grapevine beetles are part of the scarab beetle family, which is generally considered harmless to humans. As such, you do not need to worry about your safety when encountering these beetles.

Damage to Gardens and Vineyards

Grapevine beetles can cause damage to gardens and vineyards, but the extent of the harm is relatively mild. Their primary target is the foliage of grapevines, as their name suggests.

However, they can occasionally feed on the leaves of other plants as well. A few key points to note about grapevine beetles in gardens and vineyards include:

• They primarily feed at night
• They are most active in the late summer
• The damage is often cosmetic rather than fatal to the plants

In a comparison of the potential damage caused by grapevine beetles versus other pests, these beetles are relatively benign.

Other pests, such as Japanese beetles, can cause considerably more harm to plants, including severe defoliation and even the death of the plants.

Pest	Potential Harm to Plants
Grapevine Beetle	Cosmetic damage (mostly)
Japanese Beetle	Severe defoliation/death of plants

Diet and Habitat

Host Plants and Foliage

Grapevine Beetles are known for their attraction to grapevine leaves and other types of foliage. While their diet also consists of other sources like tree sap, some examples of their preferred host plants include:

• Grapevines
• Maple trees
• Deciduous trees

Nocturnal Behavior and Tree Stumps

These beetles exhibit nocturnal behavior, making them more active during the night. They tend to hide in tree stumps and soil during daylight hours. Here are some characteristics of their habitat:

• Woodlands
• Thickets
• Vineyards
• Deciduous forests

While Grapevine Beetles may be a nuisance to some plants, they pose no harm to humans. The table below compares some of their features to further illustrate this fact:

Feature	Grapevine Beetles	Harmful to Humans?
Diet	Foliage, Tree Sap	No
Habitat	Woodlands, Vines	No
Activity Period	Nocturnal	No

Natural Enemies and Control Methods

Predators and Beneficial Insects

Grapevine beetles have natural enemies that help keep their population in check. Some of these predators include:

• Birds: Many bird species consume beetles and their larvae as a food source.
• Lacewings: These insects prey upon beetle larvae and other small pests.
• Dung Beetles: While not directly feeding on grapevine beetles, they help in breaking down and recycling organic matter, benefiting the soil ecosystem.
• Beneficial nematodes: These microscopic worms attack and kill beetle larvae in the soil.

Insecticides and Chemical Control

In situations where grapevine beetle populations are high, chemical control may be necessary. Some common insecticides used for beetle control include:

• Pyrethrin: A natural insecticide derived from chrysanthemum flowers.
• Spinosad: A naturally occurring soil bacterium used as an insecticide.
• Insecticidal soap spray: A less toxic option for controlling soft-bodied pests like larvae.

Insecticide	Pros	Cons
Pyrethrin	Natural, effective against adult beetles	Short residual, toxic to bees
Spinosad	Low toxicity to humans, long-lasting	Harmful to some beneficial insects
Insecticidal soap	Safe for humans, pets, and plants	Less effective against adult beetles

Organic Control Measures

For an organic approach to grapevine beetle control, these techniques can be considered:

• Neem oil: A natural pesticide extracted from the seeds of the neem tree.
• Diatomaceous earth: A powdery substance made from fossilized aquatic organisms that kill insects by damaging their exoskeletons.
• Sticky traps: Used to monitor and trap adult beetles.
• Organic gardening practices: Cultivating a diverse garden with plants that attract beneficial insects and predators.

Examples of organic control measures:

• Applying neem oil or diatomaceous earth to the soil and plants to deter beetles.
• Placing sticky traps near grapevines to catch and monitor adult beetles.
• Planting various flowers, such as marigolds or sunflowers, to attract predators of beetles.

Comparison to Similar Insects

Japanese Beetles and Their Impact

Japanese beetles are invasive insects that can be harmful to various plants. They feed on the leaves of numerous plants, causing them to appear skeletonized¹. However, they are not harmful to humans.

Characteristics of Japanese Beetles:

• Metallic green and copper color
• About ½ inch long
• Feed on plants in their adult stage

Other Beetle Species

There are numerous other beetle species that exhibit varying levels of impact on plants and humans. Here, we examine a few examples.

Weevils

Weevils are small beetles that can cause damage to stored grains and seeds. They typically do not directly impact humans².

Stag Beetles

Stag beetles are characterized by their large, pincer-like mandibles. These beetles are not considered harmful to humans, and their larvae feed on decomposing wood, often found in gardens.

Flea Beetles

Flea beetles are small and can jump like fleas when disturbed. They cause damage to various plants by feeding on the leaves, creating small holes⁴. They do not pose a threat to humans.

Blister Beetles

Blister beetles are so named because their body fluids can cause skin irritation, including blistering. They can be harmful to humans if mishandled.

Ground Beetles

Ground beetles are generally not harmful to humans, and can even be helpful as they feed on pests like slugs and caterpillars⁶.

Rhinoceros Beetles

Rhinoceros beetles are large and uniquely shaped, with a horn-like structure on their heads. They feed on plant material and don’t pose any significant threat to humans⁷.

Comparison Table

Beetle Species	Impact on Plants	Harmful to Humans
Japanese Beetles	Significant	No
Weevils	Moderate	No
Stag Beetles	Minimal	No
Flea Beetles	Moderate	No
Blister Beetles	Moderate	Yes
Ground Beetles	Minimal	No
Rhinoceros Beetles	Minimal	No

Additional Grapevine Beetle Information

Lifespan and Reproduction

The lifespan of a Grapevine Beetle is typically around one year, from egg to adult. During their short life cycle, they go through several developmental stages:

1. Eggs: Female beetles lay eggs after mating, usually on decaying wood and leaf litter.
2. Larvae: The eggs hatch into white larvae (grubs) that feed on rotting wood.
3. Pupae: After growing and shedding their exoskeleton multiple times, the larvae pupate.
4. Adults: Finally, the pupae transform into adult beetles, ready to mate and begin the cycle again.

Characteristics of the Grapevine Beetle Lifecycle:

• The development from egg to adult typically takes less than a year
• Eggs laid on rotting wood or leaf litter
• Grubs feed on rotten wood, while adults feed on deciduous plants

Grapevine Beetles don’t generally harm humans, but if you are growing apple trees or grapevines, it’s essential to monitor their presence and any potential damage they may cause to these fruit-bearing plants.

The proactive approach includes checking for black spots on leaves, rotten wood, and decaying portions of the plants to address infestations as soon as they appear.

Conclusion

Since grapevine beetles are usually found in gardens and vineyards, people often consider them harmful.

However, these distinctive insects, with their eye-catching appearance and habits, do not pose a direct threat to people. These insects feed on plant foliage, and grapevine beetles focus on vegetation and refrain from harming humans.

Yes, they can cause damage to plants, but it is nothing too drastic. However, you can use the tips and tricks mentioned in the article to get rid of them.

Understanding their characteristics, habits, and role in ecosystems can help us appreciate these beetles without undue worry about personal harm.

Footnotes

1. https://extension.umn.edu/yard-and-garden-news/dont-fall-japanese-beetle-trapping-trap ↩ ↩² ↩³ ↩⁴

2. https://www.extension.purdue.edu/extmedia/e/e-251-w.pdf ↩

3. https://www.rhs.org.uk/advice/profile?pid=525 ↩

4. https://extension.umn.edu/yard-and-garden-insects/flea-beetles ↩

5. https://ento.psu.edu/extension/factsheets/blister-beetles ↩

6. https://entomology.ca.uky.edu/ef103 ↩

7. https://www.eppo.int/ACTIVITIES/plant_quarantine/regulated_lists/Alert_List_-_NEW_ENTRIES/hb/l.teren_-64.jpg/image_view_fullscreen ↩

Reader Emails

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

Letter 1 – Grapevine Beetle

What is this HUGE beetle??
June 29, 2010
My husband and I were freaked out to find this beetle flying around our living room. We trapped it and let it go outback, but before it flew off I was able to snap some photos…

I thought it might be a female Hercules Beetle, but the spots throw me off. What do you think it is??
Thanks!
Northern Missouri

Your beetle is a Grapevine Beetle, Pelidnota punctata.  Like the Hercules Beetles, it is in the family Scarabaeidae, but it is subcategorized as a Shining Leaf Chafer in the subfamily Rutelinae. 

The species name, “punctata” means “spotted” according to BugGuide.

Thanks!! I did some more searching last night and finally found it, but you just confirmed it for me!!

Letter 2 – Grapevine Beetle

Beetle identification assistance.
Location: Chicago, Illinois, United States
July 13, 2011, 2:12 pm
To whom it may concern,
Would you please help me with the identification of this interesting beetle?
I found it cuddling up near a light bulb and I transported it to a tree after watching him for a while.

The beetle is about an inch in length and approx half an inch in width. All four legs have hook-like claws. It also has two sensors that are orange and similar to a flower pedal I think it may be attracted to light as I spotted a large flying beetle circling the same light the previous night.

Thank you for taking the time to read my letter and have a nice day.
Signature: Sincerely Thomas

Hi Thomas,
We have been receiving numerous reports of Grapevine Beetle, Pelidnota punctata, and sightings this summer.  This large scarab beetle feeds on the foliage and fruit of grapes and the beetle grubs develop in rotting logs.  You can see BugGuide for additional information.

Letter 3 – Grapevine Beetle

Subject: Huge ladybug/beetle?
Location: Barrie, Ontario, Canada
July 19, 2012 6:16 pm
I came across this bug sitting among our Virginia creeper. At first glance, I thought it was a mutated ladybug because of the size (1 inch). It flies quickly but not far (didn’t like the camera in its face i suspect).

Perhaps it’s some type of beetle? I’ve been searching internet sites for answers with no success. I hope you can help.
Thank you very much
Signature: Jennifer

Hi Jennifer,
Even though it is orange with black spots, this Grapevine Beetle is a Scarab Beetle and it is not even closely related to a Ladybug.

Letter 4 – Attempted Interspecies Mating?? Mating Japanese Beetles and Grapevine Beetle

Food chain or strange threesome?
Location: Rockford, northern Illinois
August 18, 2011, 6:49 pm
Dear Bugman,
I would like to identify the large orange and black beetle sitting atop the mating pair of Asian beetles. I found them on the underside of a grape leaf in my backyard in Rockford, IL.

At first, I thought that the large beetle was eating the smaller ones, then I thought maybe it was trying to mate with them. Either way, he certainly was hanging on to them.

I would appreciate anything to let me know if it’s beneficial or not, not as if the Asian beetles haven’t already done a number on the grapevine…..
Sincerely,
Signature: Amy Berogan, Rockford, IL

Dear Amy,
It isn’t often that we are taken totally unawares by a photograph, but your images of mating Japanese Beetles with a Grapevine Beetle gave us a drop jaw moment.  We recently featured another photo sent to us by the Phoenix Zoo staff that appears like an attempt at interspecies mating. 

Many other introduced species are known as Asian Beetles, including the Multicolored Asian Lady Beetle and the Asian Longhorn. 

To avoid confusion, your pair is known as Japanese Beetles, one of the most well-known and reviled Invasive Exotic species to plague North American gardeners since the beginning of the 20th Century. 

They are known to feed on the flowers and leaves of more than 100 cultivated plants, and they are especially fond of roses, roses of Sharon, and fruit trees.  The larger Grapevine Beetleis native and adults are often found eating the leaves of grapes. 

Both are in the subfamily Rutelinae, the Shining Leaf Chafers and we can only hope that they are so distantly related that there will be no progeny produced by this unnatural sexcapade. 

Gardeners will likely throw in the trowels should a hybrid suddenly appear that is the size of a Grapevine Beetle with the ravenous feeding habits of the Japanese Beetle.  Perish the thought.  

Thanks, Bugman!  You know, my boyfriend said the same thing when I showed him my photo..let’s hope we don’t get huge Japanese beetles, then my grapes just won’t have a chance!

I’m including another photo that I didn’t send at first because I didn’t think it was of the same quality as the other photos, but it does show some sort of ovipositor or penis thingy coming from the rear end of the Grapevine beetle toward the Japanese beetles. 

I couldn’t believe my eyes either. Let’s just pray, as you said, that no progeny are produced!!!
Thanks again and love love love your site,
Amy Berogan

Letter 5 – Bug of the Month July 2016: Grapevine Beetle

Subject: Idk what it is
Location: Womelsdorf pa
June 29, 2016, 2:57 pm
This Beatles looking about the size of a dime if not a bit bigger has been on our outside light for a few days.
Signature: Connie Wansley

Dear Connie,
Also known as a Spotted June Beetle, this Grapevine Beetle, Pelidnota punctata, is closer to the size of a quarter than a dime.  They are about an inch long.  Since it is the end of the month, we need to select a Bug of the Month for July 2016, and we have decided to feature your submission. 

According to BugGuide:  “Adults feed on grape (Vitis) foliage and fruit Larvae host on dead Acer, Celtis, Juglans, Malus, Platanus, Quercus, Ulmus spp [a variety of hardwood trees]” and “Eggs are laid on stumps and rotting logs.

Larvae feed on decaying roots and stumps of trees, pupate in adjacent soil. Adults emerge May-September and come to lights.”  According to the University of Wisconsin at Madison: 

“Look for GBs east of the Great Plains, in woodlands, thickets, vineyards and gardens – places where rotting wood/stumps are found near grape vines. Adults eat the leaves of grape (wild and domestic) and Virginia creeper (and there’s one account of a GB browsing on spinach in a garden), and the larvae (grubs) feed on rotting wood.

Most sources say that the adults do minimal damage in a well-kept vineyard and do not need ‘controlling’.  Ms. GB lays her eggs in stumps and other rotting wood, or on the ground near stumps and rotting wood, apparently favoring dead elm, oak, maple, apple, and hickory.

The pale, C-shaped larvae hatch two weeks later, dig/bore in, and feed – and feed, and feed – for the rest of their first year and through their second summer. They eventually reach two inches in length and pupate underground, not surfacing until they emerge as adults the following year.” 

Letter 6 – Fanmail and Grapevine Beetle

Thank you
June 13, 2011 7:17 am
Hi Bug Folks,
This morning when I went outside, we had two grapevine beetles on our screen door. I didn’t know that at the time, of course, but a quick search of What’s That Bug gave me the information I needed.

I use your site several times a year, and I don’t think I’ve ever written to thank you for it.
I have three children, the oldest of whom is nine, and a brief search has rescued many a scary-looking bug from this paranoid mother.

When my daughter was waking up with bites on her arms, you helped me identify the culprit (spider), and when I found small bugs on our comforter, you relieved my bedbug paranoia (carpet beetles).

When we find unknown bugs in the house, I use the site to determine how far away we take them when we show them out (just outside the door, way out in the backyard, or down the road?).

I’ve even learned to tolerate the occasional house centipede.
I was a teacher/naturalist at a bird sanctuary for many years, so I’m a live-and-let-live person by nature and training, but being a mother has given me a twitchy stomping foot

(That’s probably not a black widow in the corner of the bathroom, but what if it is? My babies!).

I appreciate your site and your attitude toward bugs, which helps temper those squash-and-ask-questions-later instincts.
I can tell that this site is a lot of work, and I just wanted you to know that our family appreciates it.
Yours,
Kara Laughlin

Dear Kara,
In our seemingly impossible task of trying to respond to the numerous emails we received during our week away from the office, the subject line generally influences which emails we read first. 

We never pass on the opportunity to read something that begins with a thank you and we were quite touched by your kind letter.  We are happy to hear that our mission to spread appreciation and tolerance of the lower beasts has struck a harmonious chord with so many readers. 

We have dredged up a photo of a Grapevine Beetle from our archives to accompany this posting.

Letter 7 – Grapevine Beetle

large pale yellow beetle and some kind of yellow hairy fly?
the beetle was approximately 1.5 – 2 inches long, very very round. pale yellow with sparingly placed black dots.

the fly was very small less than an inch long, and as seen in the picture had a long needle with which to feed. it was also quite a hairy coarse hair. and yellow anyway i would like to know if possible the species name and any sites containing more info. thanks for your time.

Josh Huling

P.S. I have a large amount of quality insect/bug/arachnid shots if ever you need any(for free) please feel free to ask.

I have a couple more photos I would like to share and learn info about. but I don’t want to bog you any more than you most likely are already

Hi Josh,
Your beetle is a Grapevine Beetle, Pelidnota punctata. Adults feed on the foliage of grapes. You can get more information on the Grapevine Beetle on BugGuide.

You can also search our archives with our search engine or peruse our 18 beetle pages for past submissions to our own site. Your fly is a Bee Fly, probably the Greater Bee Fly, Bombylius major.

Once again, you can search BugGuide and our own archives for more photos and information.

Letter 8 – Grapevine Beetle

Flying Beetle?
Hi,
I live in Toronto, Canada, and found this flying around my front porch last night once the sun had gone down. It was fairly passive and large than a June bug, about an inch long. Thanks,
Grant Foster

Hi Grant,
We have been receiving numerous inquiries daily regarding the identification of the Grapevine Beetle, Pelidnota punctata, but all of the images have been blurry. Thanks for sending us a focused photo worth posting.

The coloration of this beetle ranges from pale cream to dark burnt orange, and black spots vary in size.

Letter 9 – Grapevine Beetle

Grapevine Beetle
July 18, 2009
Found this 3 cm-long beetle a few days ago in a patch of clover on my lawn. From your site, I determined that it’s a Grapevine Beetle. I have no grapes, but some of the neighbors probably do.
Ray
Toronto, Ontario, Canada

Hi Ray,
Your identification of the Grapevine Beetle, Pelidnota punctata.  This species ranges in color from a very pale yellow to a rusty red, but the spots remain a consistent identification feature.

Letter 10 – Grapevine Beetle

High quality grapevine beetle photos, and eastern bloodsucking conenose (I think)
July 2, 2010
Hey bugman,
the other night I was outside taking photos of the Conenose (I believe courtesy of bugguide, that’s what it is), which was sitting beside the outside light when I suddenly heard a loud buzzing.

I turned around and saw what I thought to be a large June beetle and after a few rather pathetic attempts to grab it as it was flying, I finally made a good attempt and caught what turned out to be a grapevine beetle instead.

I was so happy as I had never found a grapevine beetle and had always wanted to. I hope you enjoy the photos as much as I enjoy your website.
Michael Davis
Seymour (just south of Knoxville), Tennessee zip code 37865

Hi Michael,
Thanks for sending us your high-quality photos.  We will be uploading your photos in separate postings to simplify our archives.

Thanks so much for responding and posting the photos! I was so happy to find that grapevine beetle, and I had never seen an eastern bloodsucking conenose either.

I made sure I didn’t touch him (the conenose) as I read that they give a nasty bite. Anyway, I just wanted to thank you for posting my photos.
Michael Davis

Letter 11 – Grapevine Beetle

Unknown Bug
Location: Brooklyn Heights, Brooklyn NY
June 30, 2011 8:01 am
Hello –
I found this bug last night in Brooklyn Heights NYC. Looks like something I’ve seen before but bigger.
Thanks
Signature: Dwight H Simmons

Hi Dwight,
This large scarab is a Grapevine Beetle, Pelidnota punctata, and you may see additional photos and read the information in our archives as well as on BugGuide.

Letter 12 – Grapevine Beetle

Bug identity
Location: Southern Ontario/Niagara region Canada
July 6, 2011, 10:45 pm
Hi guys, found your website while trying to identify this bug/beetle. Flew into my woodworking shop at 10 pm. Trapped it in a mason jar. Almost seems like a milkweed borer( I grow it for the monarchs) but is not cylindrical like the descriptions that I found.

I burn firewood from local sources for heat in winter. I also do woodworking with an extensive and expensive supply in my shop. My questions to you are; What is it? what is its habitat? is it a beneficial insect? a ladybug on steroids?

We live in a fruit and grape growing area under quarantine for several diseases and insects, ash borer being the big one right now. I don’t want to release this without more info in case it is invasive.

All info is appreciated and I thank you for it. I live in the southern Ontario/Niagara region and it visited me in early July.
Signature: Dan Gilliam

Dear Dan,
This is a Grapevine Beetle, Pelidnota punctata, and it is a local species for you.  They feed on the leaves of grapes, but they are not considered a threat to the vineyards.

Thanks for the info and the time to reply. I’ll let him go immediately. Dan

Letter 13 – Grapevine Beetle

Big ass beetle
Location: Middletown RI
July 12, 2011 10:49 pm
He was large and very stubborn when I tried to take him outside… Was around 1030pm when he flew into my garage and went straight for the light… Finally got him outside.
Signature: -Erin

Dear Erin,
This is a Grapevine Beetle, and like many beetles, they are likely attracted to artificial lights.

Letter 14 – Grapevine Beetle

beetle
Location: A table (on Long Island, NY)
August 5, 2011 10:50 am
Hi,
I’m on long island and found this grapevine beetle in my backyard. I actually did not know what it was at first until i found this website and compared pictures haha. My question is, is this a rare bug to find in this area?
Signature: Dookey

Hi Dookey,
The Grapevine Beetle is not rare, and though we cannot provide any concrete data, we can say that the identification requests we received this year are up from previous years. 

Since there are vineyards in New York, it stands to reason that Grapevine Beetles might be more common there than in other places.

Letter 15 – Grapevine Beetle

Subject: Female Eastern Rhinoceros Beetle?
Location: Northern Illinois
June 25, 2012 8:31 am
Hello! Can you help me identify the attached beauty?
It was frolicking in my grape vines yesterday, 6-24-2012.
Signature: Rachel White

Hi Rachel,
Like the Rhinoceros Beetle, this Grapevine Beetle is a Scarab Beetle, but in a totally different subfamily.  Adults feed on the leaves and fruit of grapes.

Letter 16 – Grapevine Beetle

Subject: Grape Vine Beetle or Female Hercules?
Location: Long Island, NY
August 4, 2012 3:49 am
I’ve been looking to identify this beetle that was on our screen the other night. But I’ve noticed a similarity between the two beetles mentioned in my subject line. Curiosity being what it is, I just was hoping you’d be able to identify which one it is. We live on Long Island, NY.

I’ve seen some like this before, as well as several times have seen a male Hercules, found one floating in our pool just last month. But we also have lots of woods and even grape vines (don’t know how literal the name Grape Vine Beetle is).

(Should note, I had a hard time getting a decent picture with the flash on my phone, the last one attached is closer to the true coloring).
Signature: Metz

Hi Metz,
The six spots on the outer edges of the elytra identify the Grapevine Beetle.  The markings on the female Hercules Beetle are much less regular and the Hercules Beetles are considerably larger than Grapevine Beetles.

Thank you very much!  🙂  I had a feeling but wanted to be sure.  I’ve put a plug-in for your site to my family and friends on Facebook!