How can I prevent powdery mildew on my begonia plant?

Powdery mildew is a common fungal disease that affects many plants, including begonias. To prevent powdery mildew on your begonia plant, provide good air circulation by spacing plants properly and avoiding crowding. Water at the base of the plant rather than overhead, as wet foliage can promote the growth of the fungus. If you notice signs of powdery mildew, remove and destroy any infected leaves or plants immediately. A solution of neem oil or a mixture of baking soda and water can also be used as a preventative measure or to control an existing infestation.