Treating Scale Insects on Holly Bushes

Identification

White, cottony spots on holly leaf undersides are soft scale insects. Their honeydew excretion often leads to black sooty mold on upper leaf surfaces. The bush was planted in 2002 in Lancaster, PA.

Control Options

Apply horticultural oil or insecticidal soap thoroughly to leaf undersides. Repeat in two weeks to catch crawlers. For heavy infestations, a systemic insecticide (e.g., imidacloprid) applied as a soil drench provides longer control. Follow all label directions.

Prevention

Monitor annually in spring. Maintain plant health with proper mulching and watering to reduce susceptibility.