If you have noticed white fuzz on the trees and leaves in your yard lately, it’s not snow or cotton — this white coating is actually insects. These white fluffy bugs are called Asian woolly hackberry aphids and typically appear in the Upper South region of the United States and in much of Asia. Although they don’t cause harm to humans, they are a nuisance to homeowners due to the sticky sap they produce.
Just like stink bugs, these pests usually appear in fall, with sightings reported in the Southeast, southern Midwest, Texas and California, according to HGTV. While the bugs don't bite or sting, they still cause a nuisance by producing a sweet, sticky honeydew as they feed on the sap of sugarberry and hackberry trees. The clear goop then falls on sidewalks, cars and anything below them.
The honeydew causes further annoyance by then promoting the growth of "sooty mold," a type of fungi that looks like, well, sooty mold. While the dark grit may cause trees to drop their leaves earlier, scientists haven't discovered any negative long-term effects. That doesn't mean homeowners don't want to get rid of the fluffy bugs though.
How to Get Rid of Woolly Aphids
To remove the fluffy aphids from your property, you can start by spraying them with water. A little bit of pressure from the hose can blast away aphids without stripping off foliage, advises horticulturist Amy Dismukes of the University of Tennessee. Prevent them from spreading further by giving shrubs plenty of TLC as well.
"As always, healthy plants are less prone to attack, so utilize some cultural controls to make your hackberry happy," she wrote in her Spring Hill Home Page column. That includes appropriate soil moisture, undisturbed roots and no fertilizers unless there's a nutrient deficiency.
Non-residual, contact insecticides may also reduce the woolly aphid population. Bonide Horticultural Oil or Safer Brand Insect Killing Soap can keep things in check, according to the University of California's Statewide Pest Management Program.
If the aphids plague your yard every year, consider applying a systemic insecticide like Bayer Advanced 12 Month Tree & Shrub Insect Control or Bonide Annual Tree & Shrub Insect Control Concentrate around trees' trunks in late winter or early spring. Never apply these products while plants bloom, as they can harm the aphids' natural enemies and important pollinators. Don't bother in the fall either, since the leaves will soon drop anyway.
While these pests may irritate you now, have hope knowing they won't stick around much longer. The first frost usually wipes mature aphids right out as their eggs over winter, creating a mess all over again next year.
Caroline is a writer and editor with almost a decade of experience. From 2015 to 2019, she held various editorial positions at Good Housekeeping, including as health editor, covering nutrition, fitness, wellness, and other lifestyle news. She's a graduate of the Medill School of Journalism and dreams of the day Northwestern will go back to the Rose Bowl.
Katarina Avendaño (she/her) is the senior SEO editor for Good Housekeeping, where she writes and edits lifestyle content and contributes to SEO strategy. Before joining GH in 2021, she was the digital editor at New York Family, where she was responsible for the website’s content and strategy. Katarina received her bachelor's degree in communications and Spanish from the University of Washington.
