What's that sticky mess under the hackberries?

Aug 15, 2014

Winged adult woolly hackberry aphid. Photo by J.K. Clark.
Winged adult woolly hackberry aphid.
The hackberry woolly aphid (Shivaphis celti), sometimes called Asian woolly hackberry aphid, infests the widely planted Chinese hackberry (Celtis sinensis) and other Celtis species. Often, the first observed sign of a hackberry woolly aphid infestation is the sticky honeydew it produces, upon which blackish sooty mold grows, creating a sticky mess on leaves and surfaces beneath infested trees.

These aphids also secrete pale wax, which covers their bodies. Woolly aphids on shoot terminals and leaves appear as fuzzy, bluish or white masses, each about 1/10 inch or less in diameter. Winged forms have distinct black borders along the forewing veins and their antennae have alternating dark and light bands.

If you have a hackberry tree and are finding copious amounts of honeydew, confirm that these aphids and not the citricola scale, another pest of hackberries, are the cause before taking any action.

Learn more about this pest in the newly revised Pest Note: Hackberry Woolly Aphid by Andrew Lawson, CSU Fresno, and Steve Dreistadt, UC IPM.

By Karey Windbiel-Rojas
Author - Associate Director for Urban & Community IPM/ Area Urban IPM Advisor
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Attached Images:

Whitish wax and sticky honeydew from Asian woolly hackberry aphid on hackberry leaves. [Photo by J.K. Clark]

Whitish wax and sticky honeydew from Asian woolly hackberry aphid on hackberry leaves.