Mildew on Begonias

Begonias add a beautiful burst of color to your home. Sometimes they also add something unwelcome: mildew growth that can take away from the plant's appearance and damage it.

Issues

• Begonias can be damaged by mildew growth. The fungus, which looks like a powdery or dusty whitish or grayish coating, damages and kills the plant tissue beneath it. This results in poor plant growth and can cause the begonia to drop its leaves, according to Cornell University Plant Disease Diagnostic Clinic.

Control

• Reduce the risk of mildew spreading from a begonia to other plants by removing all dropped leaves and dead portions of plants. Reduce the humidity levels around the plant. If the mildew does not fade on its own, you can spray the begonia with a fungicide containing potassium bicarbonate or neem oil.

Prevention

• Some begonias are more likely to develop problems with mildew than others. If mildew has been an issue in the past, you might want to choose a more resistant variety. Keeping humidity levels in your home low and making sure the begonia has good air circulation around it will reduce the risk of mildew returning, according to the American Begonia Society.