Sooty Mold on Foxtail Palms: Caused by Scale or Aphids

Sooty Mold on Foxtail Palms: Caused by Scale or Aphids

Three foxtail palms with black fungus (sooty mold) on leaves, sticky residue, but growing well: sooty mold grows on honeydew from sap-feeding insects (scale or aphids), not a parasite itself.

Control

• Inspect fronds/undersides for brown oval bumps (scale) or small soft insects (aphids).
• Bayer Advanced Tree and Shrub Insecticide soil drench kills insects systemically.
• Sooty mold will weather off or can be washed with mild soap water.

Note

Laundry detergent spray is ineffective on the cause; target the insects. Bayer product works in 1–2 weeks, protects 1 year.