How to Remove Sooty Mold

Sooty mold is a black or bluish mold that can be found growing on a variety of plants. This mold is both unsightly and damaging to your plants. The sooty mold coats branches and leaves with a velvet-like layer of mold. This mold may interfere with the plant’s natural process of photosynthesis. This can impeded the growth of the plant and make it more susceptible to diseases. Sooty mold grows when a sticky substance--called honeydew--is secreted by pests onto the plants. To control sooty mold you must rid the plant of the pests causing the problem.

Things You'll Need

• Water
• Bucket
• Mild dish-washing liquid that does not contain bleach
• Garden sprayer
• Garden hose
• Horticultural oil

Instructions

1. Create a cleaning solution to remove the sooty mold. Pour 1 gallon of water into a bucket. Add a few drops of a mild dish-washing liquid that does not contain bleach.

2. Pour the cleaning solution into a garden sprayer.

3. Soak the plants with the cleaning solution to remove the sooty mold. This solution will only remove the surface sooty mold. It will not kill it.

4. Rinse the cleaning solution from the plants by hosing them down with a garden hose.

5. Fill a clean garden sprayer with horticultural oil. Each brand and type of horticultural oil will have its own set of specific instructions. Follow all directions and warnings for your brand of oil.

6. Spray the plants liberally with the horticultural oil. Spray on a warm, sunny day when there is not much wind.

7. Wait 10 days and apply another treatment of horticultural oil to the plants.

Tips & Warnings

• Use horticultural oil that is approved for your specific type of plants.

• Apply the horticultural oil on a day when the temperature will not reach above 90 degrees F.

References

• Ohio State University Extension: Sooty Molds on Trees and Shrubs
• University of Minnesota Extension: Scale Insects of Trees and Shrubs
• The Yard Fairy Inc.: Dormant Oil as an Eco-Friendly Pesticide