Sticky Substance on Acer (Maple) Leaves: Honeydew from Aphids or Scale

Identify and Treat

The sticky coating is honeydew—excrement from sap-sucking insects (aphids or scale). Check leaf undersides and stems for small green/brown insects (aphids) or immobile bumps (scale).

Treatment

• Spray horticultural soap or oil, covering all surfaces, especially undersides.
• Repeat in 7-10 days to catch newly hatched nymphs.
• Ants farming the insects? Control ants with baits to help natural predators work.

Healthy maples tolerate light infestations, but heavy honeydew leads to sooty mold.