Bark Aphids: All You Need to Know for a Healthy Garden

Bark aphids are a common pest that can cause damage to a variety of plants.

These small, soft-bodied insects are typically found on the bark of trees and shrubs, feeding on the plant’s sap.

Female Bark aphids are usually, 6 mm in length, with a 3.5 mm wide abdomen, 3 mm long antennae, and 9 mm long posterior legs. Winged aphids are slightly bigger.

In color, they are either light or dark brown and may have a few small spots here and there on their bodies.

Bark Aphids
Bark Aphids

It’s important for gardeners and homeowners to understand how to identify and manage bark aphids effectively.

To help control these pests, you can use less toxic methods such as periodic strong sprays of water or employ biological control methods, like introducing beneficial insects.

Being well-informed about these insects and their behavior can make a significant difference in maintaining the health of your plants.

What are Bark Aphids?

Bark aphids are small insects that belong to the family Aphididae. They primarily feed on plant sap from the bark, leaves, and other parts of their host plants.

Species Information

  • Domain: Eukaryota
  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Insecta
  • Order: Hemiptera
  • Suborder: Sternorrhyncha
  • Family: Aphididae
  • Genus: Longistigma
  • Species: L. caryae

Physical Characteristics

  • Size: Usually 6 mm long
  • Body shape: Pear-shaped
  • Antennae: Two long antennae present
  • Wings: May develop wings to migrate
  • Soft-bodied
  • Brown colored

Life Cycle

  1. Eggs: Laid on host plants in winter
  2. Nymphs: Hatch in spring and go through four stages
  3. Adults: Winged or wingless, reproduce

The life cycle of bark aphids consists of the following stages:

StageDescription
EggsLaid on host plants during winter, often near buds or bark
NymphsHatch in spring and go through four developmental stages
Adult aphidsCan be winged or wingless; reproduce both sexually and asexually

Giant Bark Aphid, Winged

Bark Aphids and Plants

Feeding Habits

Bark aphids feed on the sap of plants. They use their slender “beak” to pierce the bark, stems, or leaves of various plants and suck out the sap.

These feeding habits make them a nuisance when they infest plants in great numbers. Bark aphids usually attack trees, shrubs and vegetable plants

As per BugGuide it can attack the following trees:  “American elm, live oak, pine oak, blackjack oak, post oak, hickory, sycamore, pecan, and golden rain tree.”

Impact on Plant Health

These tiny pests can cause significant damage to plants if left unchecked. Their feeding on plant sap leads to several issues, such as:

Honeydew: As aphids feed on plant sap, they excrete a sweet, sticky substance called honeydew. This can lead to other pest infestations or cause a sticky residue on surfaces.

Sooty mold: Honeydew can also promote the growth of sooty mold, a black mold that grows on the honeydew and can block sunlight, hindering photosynthesis.

Galls: Some species of aphids inject a substance into the plant tissue as they feed, causing abnormal growths called galls. These galls can disfigure the plant and inhibit growth.

Apart from this, bark aphids can event transmit viral diseases to plants as they feed.

Bark Aphids and Other Insects

Natural Predators

Bark aphids have several natural predators that help control their populations, including:

  • Ladybugs: Effective predators known to consume aphids
  • Lacewings: Their larvae, known as lacewing larvae, are skilled at hunting aphids
  • Parasitic wasps: Lay eggs inside aphids, eventually killing them while providing a food source for the wasp larvae
  • Hoverflies: Their larvae feed on aphids
PredatorEffectivenessBenefit
LadybugsHighConsumes many aphids
Lacewing larvaeHighEliminates aphids
Parasitic waspsModerateReduces aphid numbers
HoverfliesModerateFeeds on aphids

Aphids and Ants

Ants and aphids share a mutually beneficial relationship. Ants feed on the honeydew produced by aphids, while the aphids receive protection from ants against potential predators like ladybugs and lacewings.

This ant-aphid relationship can result in large numbers of aphids on trees and shrubs.

Breaking the aphid-ant relationship helps to reduce aphid infestations and allows beneficial insects to naturally control aphid populations.

By minimizing honeydew-producing insects, ants can be discouraged and attracted to alternative food sources, promoting the presence of aphids’ natural predators.

Conclusion

In conclusion, bark aphids are small, brown, pear-shaped insects that belong to the aphid family.

They pierce the bark, stems, or leaves of trees, shrubs, and vegetable plants and suck out the sap. These pests produce honeydew, a sticky substance that attracts ants and sooty mold.

They can also cause galls and transmit viral diseases to plants. You can use natural predators, such as ladybugs, lacewings, parasitic wasps, and hoverflies, to help control their populations.

Reader Emails

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

Letter 1 – Giant Bark Aphids and Yellow Jacket

Subject: mass of bugs on downed sycamore
Location: Baltimore, MD
August 20, 2012 11:08 pm
I noticed masses of this bug on a sycamore that had been downed by a recent storm. This part of the tree was leaning, not on the ground. The tree is located in a park in woods near freshwater wetland.
I’ve included one photo with a bee to provide size comparison.
Thanks.
Signature: Martha

Giant Bark Aphids and Yellow Jacket

Hi Martha,
You have submitted photos of Giant Bark Aphids,
Longistigma caryae, and here is what we learned about them on BugGuide

“This is the largest aphid in North America with adults averaging about 1/4 inch long. They also have long legs which makes them appear even larger. Males and some females are winged but egg laying females are wingless.

They are brown with black markings (giving them somewhat of a mottled appearance) and have short, black cornicles. When alive they are often partially covered with a bluish white, waxy secretion.  

BugGuide continues:  “Activity usually begins in late April in Oklahoma. An adult female gives birth to live young and a colony is formed on the underside of the branches of the host tree.

Several generations occur during the summer and fall. Activity continues into mid-November in some years. Late in the fall females lay eggs in bark crevices or on the smooth bark of smaller limbs.

The eggs are yellow when laid but later turn black. They are the overwintering stage.”  Sycamore is listed on BugGuideas a host plant and the complete list of host plants is:  “American elm, pin oak, live oak, post oak, blackjack oak, pecan, hickory, sycamore, and golden rain tree. Other trees which might be infested include maple, basswood, birch, beech, walnut, chestnut, and willow.” 

We suspect the felled tree was oozing sap which attracted the Yellow Jacket.

Giant Bark Aphids

Letter 2 – Giant Bark Aphid

Subject: Unidentified insect – white w/ black dots, wings
Location: Port Arthur, TX
November 29, 2012 10:29 pm
Hello!
Every day I take several trips to my backyard to check the pool for any insects or spiders that may have fallen in. Today (11-29-2012) I found this little insect which is one I have never seen before. I’ve tried doing a bit of investigating on my own, but this has me stumped.
Signature: Casey B

Giant Bark Aphid

Hi Casey,
According to BugGuide, the Giant Bark Aphid,
Longistigma caryae, is:  ” the largest aphid in North America with adults averaging about 1/4 inch long. They also have long legs which makes them appear even larger. Males and some females are winged but egg laying females are wingless.” 

The host trees, according to BugGuide, are:  “American elm, pin oak, live oak, post oak, blackjack oak, pecan, hickory, sycamore, and golden rain tree. Other trees which might be infested include maple, basswood, birch, beech, walnut, chestnut, and willow.”

Giant Bark Aphid

Letter 3 – Giant Bark Aphids

Subject: What are these?
Location: Washington, DC
May 18, 2015 5:39 pm
Today, 05/18/05, I took this picture on a tree in Washington, DC. I thought they were spiders at first, and then I noticed that a couple have wings! I’ve done a ton of internet research and I can’t find anything like them. Please help!
Signature: ?

Giant Conifer Aphids
Giant Bark Aphids

These are Giant Bark Aphids, Longistigma caryae, the largest Aphids in North America.

Oh my god, thank you SO much!!!  They sure are! 🙂

As an unrelated aside, we learned this morning while watching CNN that the popular internet initials OMG have another meaning.  The report on the Waco, Texas melee refers to the Outlaw Motorcycle Gangs as OMG.

Letter 4 – Giant Bark Aphid

Subject: Whats this bug?
Location: Hillsboro, MO
October 21, 2015 2:58 pm
I was feeding my
Cows and after i was done i went to sit down on the fourwheeler and then saw this bug land on it dont know what it is please help?!
Signature: I dont know this question?

Is there anyone working for this site?

Please understand that we have a very small staff that does this as a labor of love. We cannot answer all submissions (not by a long shot). But we’ll do the best we can!

Giant Bark Aphid
Giant Bark Aphid

We really do try to respond to as many requests as possible.  Thanks for resubmitting your image.  This is a Giant Bark Aphid,  Longistigma caryae, which you can find pictured on BugGuide

According to BugGuide:  “This is the largest aphid in North America with adults averaging about 1/4 inch long. They also have long legs which makes them appear even larger. Males and some females are winged but egg laying females are wingless.

They are brown with black markings (giving them somewhat of a mottled appearance) and have short, black cornicles. When alive they are often partially covered with a bluish white, waxy secretion. ” BugGuide also notes that host plants include: 

“American elm, pin oak, live oak, post oak, blackjack oak, pecan, hickory, sycamore, and golden rain tree. Other trees which might be infested include maple, basswood, birch, beech, walnut, chestnut, and willow. ”

Wow thankyou so much! And sorry about the rush. Awrsome website thankyou for the help

Letter 5 – Giant Bark Aphid

Subject:  Large abdomen bug with wings
Geographic location of the bug:  Southern Alabama, USA
Date: 11/16/2017
Time: 12:10 PM EDT
I’ve scoured the site, but have come up empty.  Could you identify this bug? Looks like flight would be impossible, I’m stumped!
How you want your letter signed:  Sam

Giant Bark Aphid

Dear Sam,
This is an Aphid, and after searching BugGuide, we believe it is a Giant Bark Aphid,
Longistigma caryae

According to BugGuide:  “This is the largest aphid in North America with adults averaging about 1/4 inch long. They also have long legs which makes them appear even larger.

Males and some females are winged but egg laying females are wingless. They are brown with black markings (giving them somewhat of a mottled appearance) and have short, black cornicles. When alive they are often partially covered with a bluish white, waxy secretion.” 

Host trees include:  “American elm, pin oak, live oak, post oak, blackjack oak, pecan, hickory, sycamore, and golden rain tree. Other trees which might be infested include maple, basswood, birch, beech, walnut, chestnut, and willow.”

Giant Bark Aphid

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.

  • 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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