Elderberry Borer: All You Need to Know in a Nutshell

Elderberry Borer is a fascinating insect that can both delight and affect gardeners. These beetles boast an attractive mix of metallic blue and orange coloring, but they are known to pose a challenge for those who cultivate elderberries. Developing an understanding of this insect can help gardeners better care for their plants and prevent damage caused by these beetles.

The Elderberry Borer (Desmocerus palliatus) primarily targets elderberry plants, as their common name suggests. Female beetles lay eggs near the base of the plant, and when the larvae hatch, they burrow into the stem, tunneling and eating their way into the roots. This behavior can weaken or even kill the affected elderberry plants, making them a concern for those who wish to grow and harvest the fruit.

Elderberries are popular for their dark purple berries, used in folk medicine and as a dietary supplement to treat colds and flu. Therefore, it is essential for those growing elderberries to be aware of the Elderberry Borer and how best to manage this intriguing fixture of the natural world.

Elderberry Borer Overview

Identification of the Borer Beetle

The Elderberry Borer, scientifically known as Desmocerus palliatus, is a beetle that belongs to the Cerambycidae family. This insect can be easily identified by its bright metallic blue body and yellow bands that resemble a wasp’s pattern. Some key features of the Elderberry Borer include:

• Metallic blue and yellow coloration
• Antennae with alternating black and yellow bands
• Presence of well-developed wings

Life Cycle of the Elderberry Borer

The life cycle of the Elderberry Borer has four main stages: egg, larva, pupa, and adult beetle. Here’s a brief overview:

1. Eggs: Female beetles lay their eggs near the base of elderberry plants.
2. Larvae: After hatching, larvae burrow into the stem, tunneling and feeding on the plant’s roots.
3. Pupae: The larva eventually becomes a pupa and, resembling a cocoon, undergoes metamorphosis within the plant stem.
4. Adult beetles: The transformed adult beetles emerge from the stem and begin their search for a mate, thus starting a new cycle.

The Elderberry Borer is known to cause significant damage to elderberry plants by attacking the stems, which disrupts water and nutrient flow within the plant. To prevent or minimize damage, monitoring and early detection can play a crucial role.

Elderberry Plant Information

Characteristics of Elderberry Plants

Elderberry plants, belonging to the Sambucus genus, are deciduous woody plants ranging from clump-like shrubs to small trees. They typically have compound leaves with serrated edges and fragrant white or cream-colored flowers, which later develop into small berry clusters. Elderberry plants prefer moist, well-draining soil and partial to full sun exposure.

Some characteristics of elderberry plants include:

• Deciduous nature
• Compound leaves with serrated edges
• Fragrant white or cream-colored flowers
• Small berry clusters

Types of Elderberries

The two commonly known species of elderberries are Sambucus nigra (European black elder) and Sambucus canadensis (American elderberry).

Sambucus nigra typically grows into a small tree, reaching heights of up to 20 feet, whereas Sambucus canadensis remains more shrub-like, growing up to 8-10 feet high. Both species are valued for their various uses, such as ornamental, medicinal, and edible fruit, as well as providing habitat for wildlife. There are also numerous elderberry cultivars available, which offer different sizes, fruit flavors, and resistance to diseases.

Infestation Signs and Symptoms

Wilting Leaves and Canes

Elderberry borer infestations cause various signs and symptoms on elderberry plants. Wilting leaves and canes are common indicators of an infestation. This might happen due to the larvae feeding on the wood, which disrupts the flow of water and nutrients throughout the plant. A few examples of wilting include:

• Leaves turning yellow and drooping
• Canes becoming weak and bending

Discolored Lenticels

Discolored lenticels are another sign of elderberry borer infestation. Lenticels are small pores on the surface of the stems and branches, essential for gas exchange. An infested plant may show:

• Dark, discolored patches on lenticels
• Swollen, damaged lenticels

Comparison Table: Wilting Leaves vs. Discolored Lenticels

In conclusion, if you notice wilting leaves, canes, or discolored lenticels on your elderberry plants, it might be a sign of elderberry borer infestation. To maintain the health of your plants and ensure a good fruit yield, it’s essential to address these symptoms early on.

Damage and Impact on Elderberry Plants

Effect on Flower and Fruit Production

Elderberry plants produce flowers called cymes, which later develop into berries. The Elderberry Borer is a beetle (Desmocerus palliates) that lays its eggs near the base of the Elderberry plant. When the larvae hatch, they burrow into the plant and cause damage. This damage can result in:

• Reduced flower production
• Smaller fruit yield
• Lower quality berries

The impact on flower and fruit production is especially concerning in the plant’s first year, where it is important to encourage root system development. One way to do this is by removing all flowers from the plants in their first year.

Impact on Plant Health and Growth

Elderberry Borer infestation can affect the health and growth of the plant in several ways:

• Damaged and weakened stems
• Increased susceptibility to diseases
• Reduced overall plant growth

One key aspect in maintaining healthy Elderberry plants is providing 1 to 2 inches of water per week and ensuring they are grown in a well-prepared soil with a pH between 5.5 and 6.5. For example, adding mulch around the base can help retain moisture and provide a better growing environment for the plant.

Furthermore, removing perennial weeds from the planting area can reduce competition for nutrients and water, which ultimately benefits plant health.

If you suspect an Elderberry Borer infestation, monitor the plants for visible damage or symptoms and consider applying products labeled for control of common pests on elderberries, such as organic options before leaf curl occurs. Always follow label instructions and make sure they are suitable for your specific growing conditions to ensure optimal plant health and growth.

Elderberry Borer Control and Prevention

Cultural Practices for Borer Control

• Planting: Choose healthy, disease-free plants for planting to reduce the likelihood of attracting elderberry borers.
• Pruning: Regularly prune dead, damaged, or infected elderberry stems to prevent borers from establishing a home. Remove pruned material from the area.
• Water and Nutrient Management: Provide 1-2 inches of water per week and balanced nutrients to ensure healthy plants that can better withstand pests like elderberry borers¹.

Chemical Treatment Options

Some chemical treatments are available for control of common pests on elderberry. Always follow label directions and restrictions when using chemical treatments.

Example of a chemical treatment:

• Product: Abound
• Application Rate: 6 to 15.5 fl. oz. per acre²

Natural Enemies of the Elderberry Borer

Several natural enemies help to control elderberry borer populations:

• Parasitic wasps: These wasps lay their eggs inside the borer larvae, eventually killing them.
• Birds: Woodpeckers, for example, feed on elderberry borer larvae found within the stems of the plant.

Comparison of Elderberry Borer Control Methods

Additional Considerations

Toxicity of Elderberry Plant Parts

Elderberry plants are known to contain toxic compounds called cyanogenic glycosides, particularly in their leaves, stems, and seeds. Consumption of these plant parts may lead to adverse health effects, such as nausea, vomiting, and diarrhea. Here are some key points to consider:

• Toxic parts: Leaves, stems, and seeds
• Symptoms: Nausea, vomiting, diarrhea

However, elderberries themselves are safe to consume when cooked, and they offer numerous health benefits.

Role of Birds in Elderberry Borer Ecology

Elderberry borers (Desmocerus palliatus) are a type of beetle that infests elderberry plants. Their larvae burrow into the plant’s stems and roots, causing damage and reduced vitality. Interestingly, birds play a significant role in the elderberry borer’s life cycle. They serve as natural predators and help control the beetle population by feeding on them.

For example, insectivorous birds like woodpeckers and chickadees can feed on larvae or adult beetles, which in turn aid in maintaining a balanced elderberry borer population. Here is a comparison of two common bird types that consume elderberry borers:

In conclusion, understanding the toxicity of elderberry plant parts and the role of birds in elderberry borer ecology is crucial to ensure safe consumption and efficient management of elderberry plants in your garden.

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 – Elderberry Borer Beetle

yellow and turquoise bug
Saw this bug while taking a walk. About an inch long for body.
Never saw such beautiful bright colors.
Looks like it’s been painted with metallic auto paint.
Kennett Square PA
Cathy &Carlos

Hi Cathy and Carlos,
This beauty is an Elderberry Borer, Desmocerus palliatus, also known as a Cloaked Knotty-Horn.   The larvae burrow into the  stems and roots of elderberry shrubs and the adults feed on pollen.

Letter 2 – Elderberry Borer in Canada

What kind of bug is this?
Location: St.John’s NL
July 12, 2011 6:34 pm
I found this bug in my backyard all over small tree. I’m worried that the bug could be dangerous and what its called. I’m going to get rid of them, but i want to know the best way possible.
Signature: worried

Dear worried,
Our geography is rusty, and we needed to decode your location, which we now realize is Newfoundland, Canada.  This elegant beetle is an Elderberry Borer.  We are guessing that the small tree is an elderberry tree and that the beetles are feeding on the pollen from the flowers.  They will help to pollinate the blossoms ensuring that the berries will follow.  BugGuide indicates that the species is uncommon, and we get very few photographs, so we hope you waited for our response before you got rid of this lovely beetle, which once appeared on a United States postage stamp.  The larvae of the Elderberry Borer or Elderberry Longhorn feed on the roots of the elderberry, but they are not considered to be a pest species.

Thank you for telling me what kingd of bug thats is, and i didnt get rid of them. I decided not to. Thanks a million

Letter 3 – Elderberry Borer

An Elderberry Borer?
Hi Bugman,
We saw this beetle flying across our garden. It’s alive and well, also very active and colourful! It appears to be an Elderberry long-horn beetle or Elderberry Borer. It was caught in Harbour Grace, Newfoundland, Canada. Do you know if it’s native to this region? Great website! Thanks,
Steve

Hi Steve,
This is an Elderberry Borer, Desmocerus palliatus, and it is a local species for your locale.

Letter 4 – Elderberry Borer

Black winged insect
Hi,
I killed this bug in my kitchen and was worried it was a cockroach. I checked all the cockroach ID pages and I don’t think this is one because of the small head. The insect is about 3/4 of an inch (2 cm) in length not including the antenna. Can you help me ID this bug. Thanks,
Matthew

Hi Matthew,
The photo you sent in does not seem to go with your letter, but it is an Elderberry Borer, Desmocerus palliatus.

Hi BugMan,
You just posted my bug and ID’s it Thanks. You’re right I sent the wrong PIC the first time. I love your site and I’m having great fun identifying the bugs I have in my yard. I found this ElderBerry Borer in the yard and my wife took a picture to see if we could figure out what it was. Thanks again,
Matthew

Letter 5 – Elderberry Borer

A Flying Beetle?
Fri, Jul 3, 2009 at 10:06 AM
Dear Bugman,
This lovely creature buzzed my face twice right in my eyes before flying slowly over to the wild grapevine and landing. It then waited for me to get a camera, but this was the best pic I could manage before it took off again. It’s about 1.5″ long, irridescent black-blue-green with an orange upper back. In the same backyard visit I saw a gorgeous dark-orange butterfly I’ve never seen before, but she wouldn’t land to pose for a pic. 🙂
Thanks, Elizabeth
Western Massachusetts, a backyard not far from a marshy thicketed area.

Hi Elizabeth,
Earlier today, we posted another photo of mating Elderberry Borers, Desmocerus palliatus, the same species as your photo.

Letter 6 – Elderberry Borer

beetle
Location: Graham County, NC (Snowbird Mountains)
June 1, 2011 7:47 am
I photographed this beetle in the mts. It was on a Mountain Ash. It is a beautiful insect.
Signature: Cherrie

Dear Cherrie,
This gorgeous beetle is an Elderberry Borer, Desmocerus palliatus.  According to BugGuide:  “Adults feed on pollen, found on flowers, especially those of elderberry,” and “Larvae feed on elderberry, Sambucus. Eggs are laid on stems, near base of plant. Larvae burrow into stems and then tunnel down to feed on living roots.”

Letter 7 – Elderberry Borer

So pretty I didn’t think it was real!
Location: Northern Michigan (lower peninsula)
June 20, 2011 11:54 pm
My friend posted this on her Facebook page, and I actually asked if it was real… the coloration made me think it was fake, or painted with glittery nail polish. She assured me that it was indeed real, and was in her friends hair, and ended up on this brush. Could you help with an identification? I would love to let her know!
Signature: Just me.

This beautifully colored beetle is an Elderberry Borer, Desmocerus palliatus, one of the Longhorned Borer Beetles in the family Cerambycidae.  According to BugGuide, it is uncommon.

Letter 8 – Elderberry Borer

Subject: Unknown bug
Location: Kanata north,ontario
March 4, 2017 7:29 am
Very curious to know what this bug is as we see different kinds of bugs we have never seen before .
Signature: Louise

Dear Louise,
This positively gorgeous beetle is an Elderberry Borer, Desmocerus palliatus, a species that according to BugGuide has:  “Larvae feed in living roots of black elderberry, Sambucus nigra. Adults feed on pollen, found on flowers, especially those of elderberry.”   The earliest BugGuide sightings are in May, and considering your location, we are surmising your images were taken during a different season.

Letter 9 – Elderberry Borer

Subject:  Elderberry Borer
Geographic location of the bug:  St. John’s Newfoundland
Date: 07/22/2018
Time: 10:07 AM EDT
Your letter to the bugman:  Hi I just want to share this pic of what I believe is an Elderberry Borer. I snapped a pic of this beauty on my back balcony July 20th 2018 here in St. John’s Newfoundland.
How you want your letter signed:  S Balwar

Dear S Balwar,
The Elderberry Borer, Desmocerus palliatus, surely is a beautiful beetle and we are thankful you submitted your image.  BugGuide still indicates it is “Uncommon” and notes it is found in “swampy areas and edges of streams with host plant.”

Letter 10 – Horned Powder-Post Beetle

Subject: Tale of two beetles
Location: Southern California, USA
May 20, 2015 2:45 pm
Hello Bugman!
I recently pulled the included two beetles from my Lindgren beetle trap. In our area here in southern California we’ve had large numbers of Pine trees in the area killed off by some type of pest. My trap is about 40 feet from several pines of various types. The trap has a generic methanol lure and one specific to western pine beetle.
I’d like to find out if the two beetles (image attached) are pests or just native harmless beetles. The one brown beetle is about 2/3 the size of a June bug (may be a small one) though their season is still about 4 weeks away normally.
The black beetle I’ve never seen before and it’s about 0.5 inches in length.
About 20 miles from my location the polyphagous shot hole borer has also been located.
Any help in Identifying these beetles would be greatly appreciated.
Thanks,
Signature: Eric

Dear Eric,
We believe, but we are not certain, that this is an Engraver Beetle in the genus Ips, based on an image of a False Five Spined Ips in “Insects of the Los Angeles Basin” by Charles Hogue, where it states:  “The adults of this species are very small (1/4 in., or 3 mm, long) and dark brown.  The prothorax is large and partly conceals the back of the head; the wing covers are finely haired and have linear series of punctures’ the antennae are clubbed.  The species develops under the bark of pines — in our area, primarily Monterey Pine.  Usually only unhealthy or cut trees are attacked, but healthy trees are sometimes infested.  The larvae make fine tunnels through the growth layer beneath the bark, and these tunnels may connect, girdling and killing the tree.”  BugGuide has a single dorsal shot of this species, but other members of the genus pictured on BugGuide have a similar profile.  The University of California Integrated Pest Management page includes the genus Ips in the table of Bark Beetles common in Southern California landscapes.  We will try to seek opinions from Eric Eaton and Arthur Evans.  Your other beetle looks like a May Beetle, commonly called a June Bug.

Hello Daniel,
Thank you very much for the quick reply.  Time to do some more research on the little beetle.
Thanks again.  I measured the beetle in question and he is 11mm long.  So almost 3 times the length of the Ips Engraver beetle.
http://cru.cahe.wsu.edu/CEPublications/FS085E/FS085E.pdf
So perhaps he is something a little different.  Or a giant 😛
Eric

Arthur Evans provides a correction
This is a bostrichid beetle, not a bark beetle. Where is it from? Size? Any other details might help to narrow down its identity.

Ed. Note:  Our response to Arthur Evans was:  “It is from Southern California and it is about .5 inch long” and we are now awaiting further information on this Horned Powder-Post Beetle in the family Bostrichidae where, according to BugGuide:  “Most species attack wood, either living, or in some cases, dead, including seasoned lumber. A few are associated with woody fungi or stored grain.”

Letter 11 – Mating Elderberry Borers

Blue and Yellow Beetle?
Fri, Jul 3, 2009 at 5:35 AM
Hi, My husband noticed these beetles all over a small tree in our backyard there are all mating and seem content to stay there doing just that… ther are kind of pretty but I am worried that they are not native to Newfoundland Canada.
Angela
Newfoundland Canada

Fear not Angela,
The Elderberry Borer, Desmocerus palliatus, is a native insect.  Considering the reported range of this Cerambycid Beetle, from Oklahoma to the east coast, and considering its striking beauty, we do not get as many reports as we would expect.  According to BugGuide, the habitat is “Swampy areas and edges of streams with host plant” and not many people live in swampy areas, so that might explain the dearth of identification requests.  BugGuide also has this information:  “Adults feed on pollen, found on flowers, especially those of elderberry, Sambucus. Life Cycle Larvae feed on elderberry, Sambucus . Eggs are laid on stems, near base of plant. Larvae burrow into stems and then tunnel down to feed on living roots. ”  We are very happy to be able to post your wonderful photo of a mating pair of Elderberry Borers.