Sooty Mold on Citrus: Controlling the Underlying Insect Infestation Safely

Sooty Mold on Citrus: Controlling the Underlying Insect Infestation Safely

10 lemon + 3 orange trees (25 yrs, Corfu, Greece). Leaves/fruit black, sticky. Grandchildren play in garden—need safe treatment.

Diagnosis

• Sooty mold = fungus on honeydew from sap-sucking insects (aphids, scale, whiteflies).
• Not a disease—insect problem.
• Mold blocks light, reduces photosynthesis.

Safe Treatment

1. Wash off mold: Spray dilute soapy water, then strong rinse. Repeat as needed.
2. Control insects: Use horticultural oil (lightweight) or neem oil—organic, low toxicity, safe for kids/pets when dry.
3. Spray thoroughly (top/bottom). Repeat 3× at 2-week intervals.
4. For tall trees: Hire a professional with proper equipment.

Avoid

Systemic insecticides (imidacloprid) – contaminate fruit, harm bees, persist in soil.

Organic oils break the cycle safely.