Crotons with Black Sticky Substance: Sooty Mold from Insects—Oil Treatment

Crotons covered in black sticky goo, fence too. Cut back, scrubbed. What is it? Will it infect soil?

Diagnosis: Sooty Mold

Fungus growing on honeydew excreted by sap-sucking insects (aphids, scale, whitefly, mealybug). Mold harmless; insects damaging.

Fix

1. Spray crotons with horticultural oil late afternoon.
2. Next morning: blast with hose—washes off mold + dead insects.
3. Repeat in 7–10 days.
4. Soil not infected—mold needs honeydew.

Prevention

Monitor for insects. Early oil spray = no mold.