Scale and Woolly Aphids on Magnolia: Identification and Control

Scale and Woolly Aphids on Magnolia: Identification and Control

White bumps on magnolia stems and a sticky residue (honeydew) on leaves indicate an infestation of scale insects and/or woolly aphids. Both pests suck plant sap and excrete honeydew, which fosters sooty mold—a black, powdery fungus that coats leaves and stems.

Treatment

• For light infestations, scrub scales off with a soft brush and spray horticultural oil during dormancy.
• Systemic insecticides (imidacloprid) applied as a soil drench provide excellent control for both pests on larger trees.
• Monitor for crawler emergence in spring and target with insecticidal soap or neem oil if needed.

Healthy, well-watered magnolias tolerate minor infestations better. Avoid broad-spectrum insecticides that harm beneficial predators.