More Powdery Mildew Talk

By Nancy Manozzi

Powdery mildew distracts from the appearance of your African violet. While not always a major threat to the life of a violet, any unchecked disease or condition can have a negative effect on your plant. Powdery mildew can rapidly go through a collection. The mildew looks like a white or grayish powder, dusted all over the leaf of the plant. This mildew will affect all parts of your African violet, including new and old leaves, the leaf's undersides, petioles, flower stalks, and petals. The mildew spores have a small sucker that penetrates the surface of the plant. It sucks the sap of the leaves for food. Powdery mildew spores are always present in your plant room. It is the environmental condition that triggers the activism of airborne fungus of the disease. The conditions listed below are major causes:

1. High humidity

2. Temperature fluctuation -- high temperatures in the day and very cool temperatures in the evening and night

3. Stale air (old air)

4. Poor air circulation

5. Plants crowded too close together

6. Low light intensity.

You can prevent powdery mildew by changing the environment of your plant room. The two most important aspects of growing conditions that prevent powdery mildew are air movement and spacing your plants. Adding a fan into the room is a good idea. Space the African violets so that the leaves do not touch each other.

Another non chemical treatment is Lysol spray. This is a decent alternative if you don’t want to use a chemical. DO NOT spray directly on the plants, but around the growing area. The propellant is very cool and can kill the tender leaves.

The one product that most people use today to control powdery mildew is Phyton 27, a copper sulfate based product. Application is to spray every 7 to 10 days when the disease appears. Always read the instructions first. Follow the directions for one gallon of water with Phyton 27. Other chemicals that may be used are benomyl and funginex.

A few words of wisdom: the best situation is to NOT get powdery mildew in the first place by following the suggestions above and do not use any method on all of your plants. Try your method of choice on a few plants first. If all looks OK after a week or two, you’re probably safe to use the method on more of your collection.