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.
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
- Eggs: Laid on host plants in winter
- Nymphs: Hatch in spring and go through four stages
- Adults: Winged or wingless, reproduce
The life cycle of bark aphids consists of the following stages:
| Stage | Description |
|---|---|
| Eggs | Laid on host plants during winter, often near buds or bark |
| Nymphs | Hatch in spring and go through four developmental stages |
| Adult aphids | Can be winged or wingless; reproduce both sexually and asexually |
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
| Predator | Effectiveness | Benefit |
|---|---|---|
| Ladybugs | High | Consumes many aphids |
| Lacewing larvae | High | Eliminates aphids |
| Parasitic wasps | Moderate | Reduces aphid numbers |
| Hoverflies | Moderate | Feeds 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
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.
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
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.”
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: ?
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!
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
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.”
Aphids reproduce through parthenogenesis. 🙂