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Woolly Aphids: What's That Fuzzy Fluffy White Stuff on My Tree?

Christine started writing about science online six years ago. She focuses on genealogy and natural sciences.

A woolly aphid colony.

A woolly aphid colony.

If you have discovered a tree with a fluffy, white, cottony looking growth on it, it's probably a colony of woolly aphids. Woolly aphids get their name from the fluffy, wax-like substance which covers their bodies and serves as a deterrent to other predators. At first glance, you may mistake them for a fuzzy mold.

What's That Fuzzy Stuff on My Tree?

From a distance, a woolly aphid colony can appear to be a fuzz or moldy growth on a tree branch. Looking at a woolly aphid colony from above, you see tiny black dots amongst the fuzzy, white, cottony substance. Those dots are the bodies of the woolly aphids.

The fluffy looking stuff is the waxy secretions that cling to the aphids' bodies. The wax secretions blow in the wind, adding to the cottony or wool-like appearance.

Are Woolly Aphids Bad for Trees?

Aphids, when in small numbers, do little damage to a tree. However, under favourable conditions, the aphid population can grow rapidly and cause serious damage to the tree during the growing season. Aphids attack trees by sucking the sap out of the leaves.

A close up look at a woolly aphid colony.

A close up look at a woolly aphid colony.

What Is a Woolly Aphid?

A woolly aphid, or Erisoma lanigerum, is a type of sucking insect that lives on the fluid of plants and trees. Adults are approximately 2 mm in length and are pinkish brown in color. Each adult woolly aphid can produce up to five young per day. The young woolly aphids are green or blue in color. After a few generations, winged adults develop to spread to new branches and nearby trees. They spread quickly, if not properly managed.

Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Family: Aphididae

Subfamily: Eriosomatinae

What Does a Woolly Aphid Eat?

Woolly aphids feed by inserting their needle-like mouth into plant tissue. This allows them to withdraw sap. They can feed on leaves, buds, bark, and even roots. As a result of feeding on sap, woolly aphids produce a sticky substance known as honeydew. This can lead to sooty mold on the plant.

Where Do Woolly Aphids Live?

Woolly aphids live all along the Northern Hemisphere. They are prevalent in states such as Vermont. That said, there are numerous species of aphids found throughout North America. These garden pests are usually most active in the springtime and decrease with a rise in temperatures.

What Is That Sticky Black Stuff Dripping From the Trees?

Woolly aphids secrete a sweet, sticky liquid called honeydew. The honeydew can drip to lower branches, leaves, and even the ground.

Honeydew is difficult to remove, but otherwise it doesn't cause any real problems. However, it does attract black sooty mold. Sooty molds are a type of fungi that grow on the sugary honeydew secreted by sap-sucking insects like aphids. Where there is black sooty mold there is always honeydew.

The picture below shows a black, sooty covering on the leaves in the center. The branch directly above the sooty covering was covered with the woolly aphids shown in the other two pictures.

Black sooty mold growing on honeydew.

Black sooty mold growing on honeydew.

Are Woolly Aphids Dangerous to People?

Some species of aphids have been reported to bite people in nature, especially species of large aphids. In general, this is quite rare. People who work with aphids in labs say that they often get bit, but they handle these insects very frequently. While it is not very common, it can happen. Nevertheless, the bite effects are not harmful. Furthermore, no known disease or parasite is transferred from aphids to humans.

How to Get Rid of Woolly Aphids

Having woolly aphids is not a major cause for concern. Severe cases are extremely rare and getting rid of a colony of them is fairly simple. The biggest hindrance is to the host plant or tree which may show signs of stunted growth, curling of the leaves, browning, or wilting.

The best solution for removing woolly aphids is to set your hose nozzle on full blast. Spraying them will knock them to the ground, and they will be unable to return to the host. Do this every few days until you no longer see any signs of them.

You can also spray them with soapy water and rub them off with a brush, rag, or sponge. It is not recommended that you use any type of pesticide on them because pesticides will do more damage to beneficial insects in your yard or garden than they will to the woolly aphids. Products containing Pyrethroids and Pyrethrin are effective on Apple woolly aphids.

How to Prevent Aphids

  • Regularly check plants for signs of infestation.
  • Encourage natural enemies like ladybirds, hoverflies, and lacewings to become established in the garden. Plant daisy-like flowers, yellow flowers, and the plant Limnanthes douglasii.
  • Avoid using broad-spectrum insecticides. These will kill beneficial insects (as well as aphids).
  • Encourage insect-eating birds such as blue tits. Hang feeders in winter and hang nest boxes in spring.
  • If you plant new apple trees, use rootstocks. Rootstocks are resistant to apple woolly aphids.

How Did I Get Aphids?

There are two ways aphids can get onto your indoor plants.

  1. There were eggs already on your plant when it was purchased.
  2. They flew in from the outside through an open window or door.

What Will Eat Aphids?

Lacewing larvae eat aphids and other small insects. They seize them with their curved jaws. They are up to 8mm long with tapered rear ends. They place sucked-out aphid skins among the bristles on their upper surface to camouflage themselves.

Are There Cheap Remedies for Aphids?

Soap and water can be used to kill aphids. The basic nature of household detergents makes them perfect for getting rid of mild aphid infestations. Dilute a few tablespoons of dish soap in a small bucket of lukewarm water, use a sponge or spray bottle to apply the mixture to the plants where aphids have taken hold.

Organic Remedies for Getting Rid of Woolly Aphids

  • Check tree shoots and bark regularly for signs of woolly aphids.
  • Scrub areas within easy reach with a brush and a bucket of soapy water.
  • Spray infested areas with a firm jet of water to help reduce aphid numbers.
  • Spray with natural fatty acids such as an insecticidal soap.
  • The parasitic wasp Aphelinus mali will attack aphids above ground level.
  • Aphid predators such as ladybirds, aphidoletes, hoverflies, and lacewing larvae can be encouraged by growing flowers which attract them.

Will Killing Aphids Ruin or Save My Garden?

While aphids play a major role in ecosystems, aphids will do harm to your garden. That said, It's important to use natural aphid killer for plants. While aphids are a nuisance, they also attract beneficial insects to your garden such as lady beetles and lacewings. Getting rid of aphids naturally can help protect the insects you want to keep around.

Aphid Genus and Where They Live

GenusRegion

Genus Anoecia

About 24 species in North America, Europe and eastern Asia.

Genus Aphis

There are about 500 species on a great variety of hosts all over the world.

Genus Toxoptera

About 4 species worldwide. They are of east Asian Origin.

Genus Melanaphis

Three European species and a few East Asian Species

Genus Brachycaudus

A genus of 50 species found mainly in the Palearctic.

Genus Corylobium

It is widely distributed in Europe and has been introduced to North America.

Genus Acyrthosiphon

A genus of about 80 species worldwide

Sources

ENTOMOLOGY at the University of Kentucky, "Woolly Apple Aphid".

Good Housekeeping, "The 10 Most Destructive Garden Insects and How to Get Rid of Them"

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2012 Christine Miranda

Comments

triumphman on September 01, 2019:

Just found a big infestation on a small tree. I thought it was fungus. Till I took one inside and examined it. It was a catarpiller with feathers White feathery wings all over the leaves. They ate most of the leaves. I sprayed them with a dish soap solution , Eco-oil, and warm water. It seemed make them curl up. I was concerned they would migrate to my deck and eat my vegees in my half 55 barrel planters. Watching closely now ! I need my vegees !

matt on September 10, 2018:

Starting fluid and a lighter work best. They aint fireproof

larry on September 03, 2018:

all my garden problems with powerdy leaves ,bigly came from my evergreen tree took care of cotton bugs thanks

Kenzie on September 23, 2017:

How do you get them away becouse they drive me crazy

Jill on August 19, 2017:

Dang! We call them "Who bugs" ie Horton hears a who. Thought they were precious,,,,,not so much now!

Janet Miller on July 20, 2017:

The sticky stuff is not all over my tree its gooie on the leaves and falls like snow from the tree i am worried about my health i have a lung condition copd need info asap. Ty

Jane Mckaig on June 18, 2017:

Thank-you so so much for this info. We thought we were going to have to chop our beloved apple tree down. My husband is out in the garden now blasting away with the hose pipe on full pelt!

Thurman Moore on October 20, 2016:

Thanks. I did spray them with soapy water but did not knock them off the tree. Will do that tomorrow. Too fr to use a hose so will put clear water in my fruit tree spray unit and use it. Very helpful.

country marian on October 03, 2016:

I have a yard full of trees that are covered with these pests. I certainly cannot wash them off with a water hose. For the past two years, I have had this problem but I am afraid to use insecticide for fear of killing birds and bees. The infestation is worse this year and I am afraid it will continue to get worse each year. This is a real problem because this black and sticky residue gets all over our cars, carport, and patio. The sticky leaves and residue gets tracked into the house. Should I break down and use Bayer Advanced Protect and Feed?

Ticia capps on September 29, 2016:

Mine are in a tree over the swimming pool, and cover it. How healthy are they for swimming?

Pinky on September 27, 2016:

I always treated my birch trees in early spring as the leaves appeared to get rid of aphids. Although the extension service will no longer recommend it (back in 1977; they did) I purchased Cygon 2E from the feed store and poured several ounces in a five gallon bucket, stir. Then following the perimeter of the upper tree line which is where your roots are int he ground, pour the watered solution. Results is No aphids for the year. When talking of a 60 ft. tree and aphid sap on vehicles, this was the only solution I found to work. I would not apply near run off to water sources or near edible gardens. Used this for over 23 years with great success. BTW, it also meant I never got aphids on my flowers as well.

Cristina on September 23, 2016:

How are you supposed to spray them off of 70ft tree?

Manish on September 11, 2016:

Thanks for the information posted, i noticed them in my yard in Houston a few weeks back and took the action of blasting them with the garden hose. Did not get all of them out in the first session, but will follow up with another in the coming days. Will post back with success :) hopefully.

Jay on September 06, 2016:

Just seen these today,cool to watch,thanks for the info on them

weaver on September 03, 2016:

The white woolly aphids seem to be only on new branches. I removed the small new branches from the tree and now I'm worried that those new small branches are where we would have had fruit next year. Am I right and should I stop removing the small new branches from the tree even though they are covered with the white woolly aphids? thanks.

Whyney1 on June 21, 2016:

I looked these suckers up last year ... in our house we've been referring to them as "sweater bugs," they look like they're wearing angora sweaters. I've been spraying with soapy water and will now try the hose method too.

Juniper on June 07, 2016:

Thank you, found them on a potted Olive Tree I bought in Tesco, have taken out of my greenhouse (it wouldn't survive outside up here in Shetland !) and put it in isolation in porch will try blasting with water hose

Nancy on August 02, 2015:

We just found this in our yard. We initially thought the black mold on the ground appeared to be a lightening strike. When we saw the fuzz covered branches above it we were quite concerned for our beautiful Maple Tree! What a relief to know our tree isn't dying. Thanks so much!

Brittany on January 07, 2014:

Thank you! Very informative. I found these buggers on my trees that we brought inside for the winter (they're saplings, and we're in an apt.). Good to know they're not harmful, and thank you for posting how to get rid of them.

Christine Miranda (author) from My office. on October 23, 2012:

Thank you for taking the time to read this Faisalb87. I appreciate your commenting.

Muhammad Faisal from Pakistan on October 23, 2012:

Nice Information

Christine Miranda (author) from My office. on September 11, 2012:

Yep, that's what I meant...pretty creeepy! :)

Annnie on September 11, 2012:

Pretty? CREEEEEPY!

Christine Miranda (author) from My office. on September 11, 2012:

Annie, I had heard of and seen green ones in vegetable gardens before but these Woolly one actually look so pretty. Until you realize its millions of little insects crawling around. Thank you for reading and leaving a comment.

Annnie on September 11, 2012:

Hi Christine.. this is an interesting hub. I took Agriculture in high school and one of the greatest challenges to farmers is Aphids. This is especially so in Africa where even the simplest of challenges can reduce a farmer's efforts to zero. I have seen the wooly aphids but the black common ones here are the worst. They lower farm yields considerably especially beans, maize (which you call corn), horticultural products especially french beans, kale and cabbage.

Christine Miranda (author) from My office. on September 09, 2012:

Thank you Bob. I have never seen anything like it. It covers the whole branch. Thanks for reading and taking the time to comment.

Bob Bamberg on September 09, 2012:

Great hub, Christine. I'm familiar with the wooly adelgid (looks similar and attacks hemlocks) but hadn't heard of the name wooly aphid. Around here it's known as a mealy bug and seems to be a particular problem of house plants. Thanks for the enlightenment. Voted up, useful and interesting. Regards, Bob

Christine Miranda (author) from My office. on September 09, 2012:

Thank you for reading and taking the time to leave a comment. If I had a choice I would take Woolly Aphids as they are white and fluffy looking, they hardly look like a bug at all. In all honesty though, I had the creepy crawlies while writing this hub. :)

Sasha Kim on September 09, 2012:

Eww.... ^_^ I don't like green aphids... I would hate to find woolly aphids in my garden ^_^ Glad to know they're easy to get rid of. Voted up and interesting!

Christine Miranda (author) from My office. on September 05, 2012:

@ Peggy. Thank you for stopping by and leaving a comment. The stark white of the aphids against the green leaves was quite unusual.

@ Teachable. It has been interesting to see the trail change from day to day over the summer. The Woolly Aphids have definitely been the most interesting so far. When the kids got off the bus I brought them into the woods and told them everything I discovered.

TeachableMoments from California on September 04, 2012:

Whooly Aphids?! The title alone caught my attention. Never heard of whooly aphids. Interesting. My daughter would have a blast investigating these things. Informative hub and I love the pics. Great job.

Peggy Woods from Houston, Texas on September 04, 2012:

This was interesting. I don't know if it was the same thing or not...but at one point there was a white web like film over some of my mother's oak trees and a tree expert said that she was not to worry. It was actually beneficial to the tree. It disappeared by itself. Your photos do make it look more fluffy and cotton like, so it was probably something else. Voted up, useful and interesting.