What Do Grapevine Beetles Eat: A Friendly Guide to Their Diet

Grapevine beetles are fascinating insects known for their striking appearance and role in the ecosystem. As a member of the scarab family Scarabaeidae, they share common features with other well-known beetles such as dung beetles, rhinoceros beetles, and Japanese beetles. With over 30,000 species worldwide, the scarab family is incredibly diverse and widespread, which includes around 1,400 species found in North America alone [source].

As their name suggests, grapevine beetles are often associated with grapevines, which begs the question, what do they eat? These beetles primarily feed on the leaves and flowers of grapevines, although they can also consume other plants as well. This feeding habit can make them problematic for vineyard owners, especially when dealing with their close relative, the Japanese beetle, known to cause more severe damage to grapevines [source].

Overview of Grapevine Beetles

Grapevine beetles, scientifically known as Pelidnota punctata, belong to the Scarabaeidae family, which includes other well-known beetles like June beetles. Sometimes referred to as spotted June beetles, these fascinating insects have specific characteristics and behaviors.

These beetles come in shades of yellow to rich saffron, featuring spots on their bodies. They can be found east of the Great Plains, in wooded areas, thickets, or even vineyards. Their front legs are designed for digging, and the ends of their antennae have distinct plates.

Moreover, grapevine beetles are nocturnal, which means they’re most active during the night. As with most scarab beetles, their primary source of sustenance is plant material. Don’t be fooled by the name, though; grapevine beetles aren’t limited to feeding only on grapevines. Here are some attributes of the grapevine beetle:

  • Scientific classification: Family Scarabaeidae, Subfamily Rutelinae
  • Commonly found east of the Great Plains
  • Yellow to rich saffron color, with distinguishable spots
  • Sturdy front legs adapted for digging
  • Nocturnal lifestyle

As part of the scarab beetle family, the grapevine beetle shares some common features with the June beetle, such as being part of the Scarabaeidae family and having similar habitats. Their primary diet consists of plant material, but paying close attention to the vine leaves, they prefer will help in avoiding any adverse effects on your grapevines. By understanding their habits and features, you can identify them easily and ensure a thriving environment for your plants.

Identification of Grapevine Beetles

Characteristics

The Grapevine Beetle (Pelidnota punctata) is easily identifiable by its distinctive features. It has a robust body covered in metallic colors, typically a mix of yellow-orange and black. The elytra, the protective wing cases, have noticeable black spots arranged in three rows on each side. The antennae are quite unique, as they are branched like a fan. Here’s a quick list of their features:

  • Metallic yellow-orange and black coloration
  • Black spots on elytra
  • Branched, fan-like antennae

Geographic Location

Grapevine beetles are found mainly in North America, spread across the eastern and central regions of the United States and parts of Canada. They are often seen in wooded areas, gardens, and vineyards.

As for their eating habits, grapevine beetles feed mostly on the leaves of grapevines, as their name suggests. However, they occasionally feed on other plants, such as Virginia creeper and wild grape. While the adult beetles may cause some damage to grapevine leaves, it’s usually not enough to pose a significant risk to your vineyard.

Diet of Grapevine Beetles

Preferred Food

Grapevine beetles (Pelidnota punctata) mainly feed on the leaves of various plant species. Besides their preference for grapevines, they are also known to consume leaves of other plants like vitis, virginia creeper, and ampelopsis.

In your garden, you might notice them munching on grape leaves, which can harm the plant’s overall health. Moreover, grapevine beetles favor consuming grapevine leaves during their larval stage.

Eating Habit

These beetles display a nocturnal eating habit; they actively look for plants to feed on during the night. As grape leaves and other plant leaves provide essential nutrients, grapevine beetles consume them to fuel their growth and development.

At night, you can often spot these beetles clinging to their preferred leaves, devouring them in the cover of darkness. Keeping this nocturnal behavior in mind, you can effectively identify and manage their presence in your garden or vineyard.

By understanding the diet and eating habits of grapevine beetles, you can better protect your plants and maintain the overall health of your garden or vineyard.

Life Cycle of Grapevine Beetles

Egg Stage

Grapevine beetles start their life cycle as eggs. After mating, females lay small, white, elliptical-shaped eggs beneath the surface of organic matter, such as compost piles, lawn clippings, organic mulch, and manure source.

Larva Stage

Once the eggs hatch, they transform into larvae, which are also known as grubs or c-shaped larvae. Grubs feed on decomposing organic material and can occasionally cause damage to the roots of plants.

Pupa Stage

The larval stage eventually evolves into the pupa stage. During this stage, the beetle undergoes significant transformation, metamorphosing from its larval form into the final adult stage. This process, known as pupation, takes place in a protective cocoon within the soil.

Adult Stage

Grapevine beetles emerge as fully-formed adults after pupation. These beetles are active flyers and have an affinity for gardens and vineyards, where they feed on plant foliage and flowers.

Habitat

Grapevine beetles are versatile in their habitat preferences, being adaptable in wild forests, gardens, and vineyards. This broad range of environments provides ample opportunities to forage and reproduce, ensuring the survival and proliferation of their species.

Damage by Grapevine Beetles

Effects on Plants

Grapevine beetles, as the name suggests, are a type of scarab beetle that can cause damage to plants, particularly grapevines. For example, they feed on the foliage of grape plants and other vegetation, like tree fruits, small fruits, and maybe even vegetables.

When grapevine beetles attack your plants, they chew the leaves, which can result in reduced photosynthesis and hinder the growth of the plant. In some cases, beetles can also cause damage to developing fruit, such as ripe apricots, caneberries, figs, grapes, peaches, and plums. Although they can be quite harmful to plants, they do not always cause severe devastation.

Effects on Humans

While grapevine beetles can be bothersome to vineyard owners and gardeners, they are essentially harmless to humans. These insects typically pose no threat to people, as they do not carry diseases or cause any harm directly to humans. They are simply considered pests due to the potential damage they can inflict on plants.

Ultimately, grapevine beetles mainly pose a risk to the health and production of your plants, especially grapevines. Monitoring your vineyard and garden can help you detect signs of grapevine beetle infestations early on so you can take necessary actions to protect your plants.

Control Measures for Grapevine Beetles

Natural Measures

To control grapevine beetles without using chemicals, consider employing beneficial organisms. One option is to introduce beneficial nematodes into your soil; these microscopic parasites can help control beetle larvae populations. Another option is using a milky spore product, which targets the larvae and reduces the beetle population over time.

Some natural substances like diatomaceous earth can be used to deter beetles. Sprinkle it around the base of grapevines to create a barrier, as this substance will cause discomfort and damage to the beetles that come in contact with it. Sticky traps are another practical tool to capture the beetles without the use of chemicals.

Lastly, fostering grapevine beetle predators in your garden, such as birds and beneficial insects, can help maintain beetle populations at a manageable level.

Chemical Measures

When natural measures aren’t enough, you may need to resort to chemical control methods. Some common chemical solutions include insecticides, insecticidal soap, and pyrethrin. Insecticidal soap spray can be used to target soft-bodied insects like aphids and flea beetles, while pyrethrin is a popular organic insecticide derived from chrysanthemum flowers that can target a range of pests.

Note that repeated applications of chemical controls may be necessary to keep grapevine beetle populations under control.

Control Method Pros Cons
Beneficial Nematodes Natural and safe for plants May take some time to see significant results
Milky Spore Targets beetle larvae specifically Takes time to build up in soil, may not be fast
Diatomaceous Earth Natural and effective as a deterrent Needs to be reapplied regularly, can harm good insects
Sticky Traps Non-toxic, captures beetles Can also trap beneficial insects
Insecticidal Soap Targets soft-bodied pests May need multiple applications
Pyrethrin Organic and effective against various pests Can be toxic to beneficial insects and fish

By combining both natural and chemical measures, you can ensure that grapevine beetle populations are managed effectively without excessive harm to your grapevines or the surrounding ecosystem.

Reader Emails

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

Letter 1 – Grapevine Beetle

 

unknown BIG beetle
Dearest Bugman~
This lovely beetle was discovered looming LARGE on our kitchen window screen this morning. What a way to start the day… Anyway after politely asking our 7 yr. old son to capture him/her (which didn’t take much cajoling) he is now taking up residence in our well-used screened-in bug house. Please help us to identify this beetle! I have looked all over the internet and I still have no clue. This beetle is almost 1" long and is a tannish-yellow with black spots and a shiny underbelly. *shiver* Thanks in advance!
The Aurella Family

Hi Aurellas,
You have a Grapevine Beetle, Pelidnota punctata. The adults eat grape leaves and the larva live in decaying stumps and roots of various trees.

Letter 2 – Grapevine Beetle

 

Subject: OLIVE GREEN BEETLE
Location: Crawfordsville, Indiana
June 27, 2017 7:58 am
Found this beautiful fairly large beetle on the window of my office at Wabash College, Crawfordsville, Indiana. Late June. Hope you can help.
Signature: Ecuaprof

Grapevine Beetle

Dear Ecuaprof,
This is a Grapevine Beetle and they are generally a pale yellow color with six dark spots on the elytra.  Some individuals lack spots and some Grapevine Beetles are more orange in color.  Here is a BugGuide image for comparison.  Your individual appears to have encountered some trauma.  One elytron appears damaged and the thoracic region appears to be separating from the abdominal region.

Letter 3 – Grapevine Beetle

 

Subject: Beetle
Location: Long Island New York
July 3, 2017 6:21 am
I assume this is some type of beetle, was about the size of a quarter and had 3 smaller ones that looked just like it following it!
Signature: Jon R

Grapevine Beetle

Dear Jon,
This distinctive Scarab Beetle is a Grapevine Beetle.  According to BugGuide:  “Adults feed on grape (
Vitis) foliage and fruit, both wild and cultivated species. Not a serious pest. Eggs are laid on stumps and rotting logs. Larvae feed on decaying roots and stumps of trees, pupate in adjacent soil. Life cycle takes about two years. Adults emerge May-September and come to lights.”

Letter 4 – Grapevine Beetle

 

Subject: Mother of all beetles?
Location: Staten island, ny
July 5, 2017 1:36 pm
This unknown bug was in my pool and I have never seen anything of this sorts by my house.
Signature: Vanessa Castris

Grapevine Beetle

Dear Vanessa,
The largest beetle in your image is a Grapevine Beetle, and the other beetles are smaller Scarab Beetles, probably May Beetles.

Letter 5 – Grapevine Beetle

 

Subject: never seen this in Detroit ever!
Location: Detroit Michigan
July 13, 2017 3:52 pm
what is this! it’s in my mailbox a d I’m scared of it! I’ve never seen this before in my life a it’s a little over an inch and a half long
Signature: I just want my mail

Grapevine Beetle

This Grapevine Beetle is perfectly harmless.  You are safe to retrieve your mail.

Letter 6 – Grapevine Beetle

 

Subject:  Curious
Geographic location of the bug:  Brimfield, Ill.
Date: 07/05/2018
Time: 12:27 AM EDT
Your letter to the bugman:  What kind of bug is this?
How you want your letter signed:  Nikole

Grapevine Beetle

Dear Nikole,
Each summer we get several requests to identify a Grapevine Beetle.  Yours is the first we are posting this summer.

Authors

    by
  • Bugman

    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.

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  • 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.

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3 thoughts on “What Do Grapevine Beetles Eat: A Friendly Guide to Their Diet”

  1. We were in bed watching the news when suddenly this huge bug flew around the TV then seemingly disappeared! Scared me almost to death. I ran to get the flyswatter while my husband looked for the bug. Suddenly, he spotted it on his pillow & whacked it hard then picked it up with tissues. As he was unraveling the tissues, we realized just how hard it’s shell was. Also, it’s legs began to move! At that point he took it away & death came to that particular beetle. I said, “Actually, it was kind of pretty”. All my husband said was, “Aren’t you glad it wasn’t a spider!”
    I am 81 & he is 88. We live in central IN & neither of us had ever seen that kind (grapevine beetle) beetle before.

    Reply

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