Dealing with Powdery Mildew on African Violets

African violets are one of the most popular flowering houseplants known for their colorful blooms and attractive fuzzy foliage. However, these plants can sometimes develop a fungal disease called powdery mildew. This white, powdery growth on the leaves and flowers can be frustrating for any African violet owner. In this article, we’ll discuss what causes powdery mildew on African violets, how to prevent it, and effective treatment options.

What Causes Powdery Mildew on African Violets?

Powdery mildew is caused by various fungal species in the order Erysiphales. The fungi produce masses of spores that appear as a white or gray “powder” on the surface of the plant.

Several factors can contribute to powdery mildew on African violets

• High humidity – Fungal spores thrive in humid conditions.
• Poor air circulation – Stagnant air allows spores to accumulate on leaves.
• Temperature fluctuations – Warmer days and cooler nights promote mildew growth.
• Low light – Plants stressed by insufficient light are more prone to disease.
• Overcrowding – Tight quarters make it easier for spores to spread between plants.

The spores are always present in the air to some degree. But when conditions are favorable, populations can explode, leading to visible outbreaks on susceptible plants

Preventing Powdery Mildew on African Violets

While powdery mildew can be difficult to prevent completely, the following cultural practices can help reduce the chances of problems:

• Provide good air circulation with fans, especially on humid days.
• Avoid overcrowding plants. Allow adequate spacing for air flow between plants.
• Keep temperatures as consistent as possible. Don’t allow more than 10°F difference between day and night temperatures.
• Provide bright, indirect light from an east or west window. Insufficient light stresses plants.
• Water carefully, avoiding wetting the leaves. Allow the soil surface to dry between waterings.
• Remove spent flowers to promote air circulation.
• Use a humidifier to maintain humidity between 40-60%. Higher humidity encourages fungal diseases.

Treating Powdery Mildew on African Violets

If your African violets do develop powdery mildew, take action right away to avoid severe infections:

Isolate infected plants to prevent the fungus from spreading. Discard any severely infected, dying leaves.

Increase air circulation with fans to disrupt the fungal life cycle.

Apply a baking soda spray – Mix 1 teaspoon baking soda per quart of water and spray plants to reduce spore germination.

Use commercial fungicides containing neem oil, sulfur, or other active ingredients. Always read and follow label directions.

Try organic sprays – Milk, vinegar, or compost tea may help control mildew. Test on a few leaves first.

Apply sulfur dust – This old-time remedy can be applied before mildew appears to deter fungal growth. But remove dust once infection subsides.

Dispose of plants that don’t respond to treatment. Severely infected violets often can’t be saved. Start fresh with new, healthy plants.

With vigilance and prompt treatment, powdery mildew doesn’t have to spell doom for your African violets. Pay close attention to growing conditions and cultural practices to discourage fungal diseases. And inspect plants frequently to spot problems early when they are easiest to control. With proper care, you can continue to enjoy the colorful blooms of healthy African violets for years to come.