Giant Conifer Aphid: All You Need to Know for Healthy Trees

Giant conifer aphids are large insects known for feeding on conifer trees. Found in various regions, these aphids can reach up to 1/4 inch in size, with some wingless and others having wings source. They thrive in areas like North Carolina and reproduce actively, resulting in several generations each year.

These insects are known for inflicting damage on trees through their sap-feeding habits. Signs of a giant conifer aphid infestation include needle drop, yellowing, and curling of the needles, alongside dieback source. If detected early, measures such as using insecticidal soap or dislodging them with high-pressure water can help manage the infestation source.

Giant Conifer Aphid: Identification and Biology

Physical Characteristics

Giant conifer aphids are soft-bodied insects often found in large groups on their host trees1. Their coloration may consist of black or purple hues, depending on the species2. These aphids have distinct long legs, and may appear wingless or winged, with both forms occurring in adults3.

Life Cycle

The life cycle of giant conifer aphids begins with overwintering as eggs on the bark or needles of host trees4. In spring, the eggs hatch, and the emerging aphids start feeding on the sap of woody areas in the trees5. During the early season, populations primarily target the terminal growth and upper areas of the tree6.

Reproduction

Giant conifer aphid reproduction involves females laying eggs on the host tree’s needles in late summer7. Interestingly, throughout the summer months, these aphids reproduce asexually8. A key aspect of their reproductive cycle is the production of winged individuals, which can spread to other host trees and continue the aphid population growth9.

Host Conifers and Signs of Infestation

Affected Conifer Species

Giant conifer aphids are known to infest a variety of conifer species. Some common host conifers include:

  • Pine
  • Spruce
  • Hemlock
  • Fir
  • Juniper

Symptoms of Infestation

Infestations of giant conifer aphids are usually identified by the following symptoms:

  • Large colonies: Aphids often form large groups on trees, especially on the terminal growth and upper areas.
  • Damage to needles: Needles may exhibit yellowing, curling, and eventually needle drop.
  • Sooty mold: This dark fungus can develop on the bark, twigs, and foliage as a result of aphid feeding.

Damage Caused by Giant Conifer Aphids

Giant conifer aphids generally cause minimal damage to their host trees. However, some possible consequences of their infestations are:

  • Stress: Trees may suffer stress due to the aphids’ feeding habits, leading to dieback or weakened growth.
  • Root damage: Although not common, root damage can occur if aphid populations are high enough.

To sum up, giant conifer aphids can cause visible symptoms of infestation on various conifer species like needle yellowing, curling, and sooty mold formation. While the overall damage is typically minimal, it is still essential to monitor affected trees for signs of stress and root damage.

Natural Enemies and Biological Control

Predatory Insects

There are several predatory insects that serve as natural enemies of giant conifer aphids. These insects help reduce aphid populations and contribute to biological control.

  • Lady Beetles: Efficient in consuming aphids, lady beetles are useful for controlling aphid populations.
  • Lacewings: Known for their larvae’s ability to consume a large number of aphids, lacewings are essential predators in biological control.
  • Hover Flies: The larvae of hover flies, also known as flower flies, are important predators of aphids.
  • Bigeyed Bugs & Minute Pirate Bugs: These insects prey on aphids and contribute to their population control.

Pros of Predatory Insects

  • Natural control method
  • Can reduce the need for chemical pesticides
  • Prevent overpopulation of aphids

Cons of Predatory Insects

  • Can be challenging to sustain their populations in monoculture systems
  • Might not be as effective in extreme aphid outbreaks

Parasitic Wasps

Parasitic wasps are another group of natural enemies that help control aphid populations. They lay their eggs inside or on the aphids, and the wasp larvae feed on the aphids, eventually killing them.

Examples of parasitic wasps include:

  • Aphelinid Wasps: These small wasps are known to parasitize aphids, whiteflies, and other small pests.
  • Aphidiid Wasps: Specialized at attacking aphids, they lay their eggs inside the aphids, which are later consumed by the emerging larvae.

Pros of Parasitic Wasps

  • Provide targeted control of aphid populations
  • Can reduce the need for chemical pesticides
  • Sustainable pest control strategy

Cons of Parasitic Wasps

  • May be sensitive to ecological disruptions
  • Might not be effective against rapidly increasing aphid populations

Comparison between Predatory Insects and Parasitic Wasps

Features Predatory Insects Parasitic Wasps
Targeted Control Moderate High
Speed of Control Faster Slower
Longevity Shorter Longer
Influence of Environmental Factors Higher Lower

Integrated Pest Management Strategies

Non-Chemical Management

  • Strong stream of water: Spray affected plants with a strong stream of water to dislodge aphids.
  • Natural predators: Introduce beneficial insects like ladybirds and lacewings to manage aphid populations.
  • Insecticidal soap: Apply insecticidal soap targeting the aphids, which is less harmful to beneficial insects. More information here.

Chemical Management

There are two types of insecticides used for managing giant conifer aphids:

  1. Contact insecticides: These insecticides directly affect aphids upon contact. Examples include pyrethroids and neonicotinoids.
  2. Systemic insecticides: These are absorbed by the plant and transported through its tissues. Aphids feeding on the plant ingest the insecticide. Imidacloprid is a common systemic insecticide.

Pros and cons of contact insecticides:

  • Pros: Fast-acting, broad-spectrum control, and relatively inexpensive.
  • Cons: Can harm non-target organisms, may require multiple applications, and pests can develop resistance.

Pros and cons of systemic insecticides:

  • Pros: Long-lasting, providing extended control, and more targeted, as pests must feed on the plant to be affected.
  • Cons: Potential for exposure to non-target organisms, possible environmental concerns, and slower-acting than contact insecticides.
Insecticide Type Pros Cons
Contact Fast-acting, broad-spectrum, inexpensive Harm non-target organisms, resistance risk
Systemic Long-lasting, targeted control Environmental concerns, slower-acting

Remember to follow the integrated pest management guidelines and only use chemical management methods when necessary.

Preventing and Treating Giant Conifer Aphid Infestations

Cultural and Environmental Practices

  • Monitoring: Regularly check your plants, at least twice a week during rapid growth, to catch infestations early and effectively ,Hose off or prune out affected parts.
  • Natural predators: Encourage predators, such as ladybirds, which help to control aphid populations naturally.
  • Environmental stress: Ensure your plants are well-watered and properly maintained, as stressed plants become more attractive to pests.

Pesticide Selection and Application

  • Insecticidal soap: A gentle, eco-friendly alternative for controlling aphids without disrupting the balance of natural predators. This can be especially useful for trees under 10ft tall.
  • Systemic insecticides: For larger trees over 10ft tall, consider using a neonicotinoid systemic insecticide in the early to late spring. Be sure to follow label directions and consult a commercial pesticide applicator if unsure.
  • Cardboard wraps and Tanglefoot: On smaller trees, wrapping trunks with cardboard or applying a sticky barrier like Tanglefoot can prevent aphid migration.
Method Pros Cons
Insecticidal soap Eco-friendly, gentle Ineffective for larger trees
Systemic insecticides Effective for larger trees Require professional application
Cardboard wraps/Tanglefoot Prevents aphid migration Only suitable for smaller trees

Remember, it is important to follow Integrated Pest Management (IPM) practices and pesticide label directions when working with chemical controls. Homeowners can also consult home & garden fact sheets for more information on preventing and treating aphid infestations in their landscape.

Footnotes

  1. https://content.ces.ncsu.edu/giant-conifer-aphids

  2. https://urbanipm.montana.edu/entomology/resources/fact-sheets/giant-conifer-aphids.html

  3. https://extension.usu.edu/pests/ipm/ornamental-pest-guide/arthopods/aphids-adelgids/giant-conifer-aphids

  4. https://urbanipm.montana.edu/entomology/resources/fact-sheets/giant-conifer-aphids.html

  5. https://www.montana.edu/extension/pubs/a-guide-to-pests-problems-and-identification-of-ornamental-shrubs-and-trees-in-montana/insects/giant-conifer-aphids.html

  6. https://urbanipm.montana.edu/entomology/resources/fact-sheets/giant-conifer-aphids.html

  7. https://urbanipm.montana.edu/entomology/resources/fact-sheets/giant-conifer-aphids.html

  8. https://urbanipm.montana.edu/entomology/resources/fact-sheets/giant-conifer-aphids.html

  9. https://extension.usu.edu/pests/ipm/ornamental-pest-guide/arthopods/aphids-adelgids/giant-conifer-aphids

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 – Conifer Aphid

 

Found on the Christmas Tree
Fri, Jan 2, 2009 at 10:28 AM
EEK! I went to take down my Christmas tree, which we cut from a tree farm in Florida. Crawling all over my angel at the top of the tree were these bugs, ranging in size from tiny (rice-sized) to one or two about the size of a fine-point Sharpie head. It has six legs, three on each side. One set appears to protrude from nose, like antenna. The next, slightly larger set is a bit further back, and the third set is still on the middle part of the body, but much longer. It is tear-drop shaped, and the butt seems to have a bit of a point to it. It’s dark gray. I thought they were ticks, but it only seems to have 6 legs. They were ALL over the angel, and moved very quickly. I am trying to decide what to do with the tree, my first inclination is to pitch the whole thing but of course it has my most expensive decorations and lights on it.
Beverly J.
Orlando Florida

Conifer Aphid
Conifer Aphid

Hi Beverly,
We wanted to check with Eric Eaton before we misidentified your insect and caused you undue alarm.  According to Eric:  “The insect is a conifer aphid in the genus Cinara.  They tend to be gray or brown rather than green, and they are quite large for aphids, too.  So, no worries.”

Letter 2 – Conifer Aphids

 

Giant Conifer aphid?
Location: Washington County MD, tree farm on mountain
January 25, 2011 12:06 pm
This year we found the prettiest tree we’ve ever dressed up for Yule, a Fraser Fir, at our beloved cut-it-yourself Christmas Tree farm.
By the beginning of January we began to notice what we thought at first were mosquitoes in the house. But they didn’t sting, and after a week or so we discovered hundreds of them, some dead, & some dying or just lethargic, under the tree and all along the window ledges. Finally I did some research and took some photos. I’ve concluded they are aphids, but not sure they are conifer aphids, as their abdomens are not round and shiny, and every last one of them we’ve seen has wings. (I thought they only had 2 wings until I got a look at the silhouette photo on a large screen- they have 4!) They look more like a shot you have of a Giant Willow Aphid, but I think they are smaller (see my shot with the Sharpie for size).
The tree farm has many different species of evergreens, and is bounded by wild hedgerows and forests. This tree came from close to an edge, where there’s a creek.
The tree, BTW, shows zero evidence of damage, and is still drinking water nearly at the end of January, down to about a cup a day. (We like to stretch the season as far as it will go :^)
We are sad the bugs were awakened/born at the wrong time of year to survive, as they are harmless and clearly just want to go outside…but with temps in the teens, that’s a dead end.
Signature: Ms.Muffet

Giant Conifer Aphid

Dear Ms. Muffet,
Thanks for your wonderful letter.  We are rushed this morning and we really wanted to post your letter and photos, but we will have to do research and supporting links at a later time.  First we want to say that a tree is much more than a tree.  It is an ecosystem.  We do not mean to imply that you should not have a living tree for the holidays, especially since Christmas Tree farms help to drive the economy in a positive way, but when a living tree of any kind is cut, more than the tree dies.  Sometimes birds are forced to abandon a nest with fledglings left to die as they are too young to fly.  We are talking about trees in general and not just Christmas Trees.  Homeowners who decide to cut a tree should realize the consequences of their actions.  Developers rarely think of the environment when they destroy native open spaces to make room for hideously ugly housing developments or strip malls.  Swamps are viewed as wastelands instead of the thriving ecosystems that exist because of the natural environment.  Enough.  We step down from the soapbox now.
We will verify that these are Giant Conifer Aphids when we have a moment after work.  Aphids are amazingly complex creatures.   Females are able to reproduce parthenogenically without males, but they only produce genetic clones of themselves in vast quantities, which is why Aphids can be so problematic on cultivated roses and other plants.  The winged forms of Aphids are the sexually reproductive generation.  Often the winged forms are different from the earlier asexual forms.  We hope we have whetted your curiosity and that we have not offended you with our rant in the paragraph above.

Giant Conifer Aphid

Update: We believe your Giant Conifer Aphids in the genus Cinara match this individual on bugGuide rather closely.

Dear Daniel,
Thank you for your wonderful reply!  I am not at all offended, I couldn’t agree with you more. I have a giant soapbox of my own I use for the same subject.  :^)  Our own land is literally a nature sanctuary, on a “wildlife superhighway” that lines a waterway.  I don’t even prune a tree without great care and respect, let alone cut one down, and I fight for dead trees to remain standing too, since they house whole civilizations! We follow the ancient habit of bringing a real tree indoors in winter and keeping lights aglow to keep alive the emotional connection to the sun’s warmth and the web of life it supports, through the dark, cold, seemingly desolate times. We don’t do it casually but with great reverence. I think it’s a northern-climate human instinct as deep as our marrow, and that’s why it endures. For the same reasons, we do all we can to avoid robbing any creature of its life or home in the process. In my 55 years, I’d never seen this phenomenon with an evergreen.  I have indeed learned a lot about aphids in the last few days and am really fascinated and amazed. I will be looking into ways of preventing a repeat of the situation in the future. Once again, many thanks for your tremendous help in appreciating the miracles all around us.
Ms. Muffet

Giant Conifer Aphid on a Sharpee

Hi again Ms. Muffet,
We finally got around to posting your photo of a Giant Conifer Aphid on a Sharpee.  We always have our photo students use a Sharpee on RC prints, but a nice #2 pencil on Fiber Based paper is best.  Tell me Ms. Muffet, do you think people would want to take a Community College PHoto Class with me for $36 a unit?  I am going to explore teaching an online class, but that takes a year to get through curriculum.  LACC could offer a course in Digital Macro Photography of Nature and the best students can have galleries on What’s That Bug.  Though we teach digital photography classes, we do not have an online curriculum developed yet.   I would like your permission to use your photo of a Giant Conifer Aphid found on the yule tree grown in Washington County Maryland.

Letter 3 – Unknown Swarm is of Woolly Aphids

 

What the hell!
Location: Spokane Valley – Eastern Washington
October 23, 2011 6:56 pm
These are some sort of gnat I think, they’re all over our tree out front. So just what are they and may I assume it’s a mating sort of thing…. huge swarm for sure! Curious about what they are and are they going to harm the tree?
Signature: Paul

Swarm of Woolly Aphids

Dear Paul,
We wish your photo showed an individual insect more clearly as it is difficult to make out details.  Our initial guess is that these might be some type of benign Barklice, though we wouldn’t rule out some species of Ant.  How long has the swarm been present?  Did it quickly disperse?

Swarm of Woolly Aphids

We will try to get a second opinion for you.

Swarm of Woolly Aphids

Not ants … here are some individual shots. We’ve seen them flying around out in front of the house for about a week now, maybe more. They’re gnat-like and seem to have powdery white’ish butt… Good shots in this batch, should help quite a lot!

Woolly Aphid

Hi Again Paul,
Your new photos are a tremendous help.  These are Woolly Aphids in the subfamily Eriosomatinae.  Woolly Aphids have complex life cycles, often feeding on different plants at different stages.  Earlier in the year, most individuals are females that reproduce parthenogenically.  We believe the winged individuals are males.  You can compare your photo to this image on BugGuide.
  Here is another photo from BugGuide.  Knowing the host tree might help to identify the species.

Woolly Aphid

 

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 – Would you take an Online Photo class with the Bugman?

 

Dear Daniel,
Thank you for your wonderful reply!

Ms. Muffet

Giant Conifer Aphid on a Sharpee

Hi again Ms. Muffet,
We finally got around to posting your photo of a Giant Conifer Aphid on a Sharpee.  We always have our photo students use a Sharpee on RC prints, but a nice #2 pencil on Fiber Based paper is best.  Tell me Ms. Muffet, do you think people would want to take a Community College Photo Class with me for $36 a unit?  I am going to explore teaching an online class, but that takes a year to get through curriculum.  LACC could offer a course in Digital Macro Photography of Nature and the best students can have galleries on What’s That Bug.  Though we teach digital photography classes, we do not have an online curriculum developed yet.   I would like your permission to use your photo of a Giant Conifer Aphid found on the yule tree grown in Washington County Maryland in this posting advertising this exciting possibility.

ANNOUNCEMENT: Dear readers, if you think it is a good idea to take an online college credit Photography class with the Bugman, Daniel Marlos, MFA Art Center College of Design 1992 for $108, please leave a comment.  If I can promise 100 students to generate FTES for a struggling campus, I may be able to get permission from the VP of Academic Affairs.

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.

    View all posts
  • 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.

    View all posts

4 thoughts on “Giant Conifer Aphid: All You Need to Know for Healthy Trees”

  1. Cool! I’m not sure if it’s an example of what to do or what not to do, but the photo is all yours.

    Count me in for the photo course! What hardware requirements will there be? I’m using a new camera (Sony SLT A33) and the only lens I have for it so far is a wide range zoom. It isn’t really intended to do macro. For that shot I was relying on the camera’s 14MP and cropping. (And lots of tweaking with Photoshop. And an old photo-enlarger rig I use as an animation stand.) But just this last week I’ve learned about putting another lens, reversed, in front to get super macro. That’s how I got the silhouette shot, but I was just holding the additional lens (an old 50mm from a ancient film camera) by hand in front, and between that and the aphid’s itchy feet, it took about 20 tries to get that one marginally decent shot. So afterwards I ordered a coupling ring for the two lenses, & I’m looking forward to playing with it a lot more. At $6.99, it beats buying a macro lens!

    I’m very excited about your plan and hope you get enough of us for the class.

    Ms Muffet

    Reply
    • Hi again Ms Muffet,
      There was some Stream of Consciousness writing in my reply that was triggered by the Sharpie, and that led to the idea. It is still much to raw of an idea for me to provide too many details, but if this does come to fruition, there will definitely be an announcement comment that should come your way via this posting. Stay tuned.

      Reply

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