powdery mildew on Begonia Masoniana
Quick answer
If your Begonia Masoniana has powdery mildew, the most likely cause is: Begonia masoniana grows from a creeping rhizome, placing it squarely in the rhizomatous begonia group, and that group is documented to come down with powdery mildew when the plants are continually subjected to poor air circulation and dank, stagnant conditions around the foliage, while the same plants will not endure constantly wet foliage or consistently damp roots.
Start here:
- 1. Move the plant into a well-ventilated spot with good light but no direct sun and open a window or run a small fan so the air around the leaves does not go stagnant.
- 2. Spray affected leaves with a fungicide labelled for powdery mildew on ornamentals, covering both surfaces, then pick off and bin any badly infected leaves rather than composting them, and water only at the soil surface so the foliage stays dry.
Why Begonia Masoniana gets powdery mildew
begonia masoniana
Begonia masoniana grows from a creeping rhizome, placing it squarely in the rhizomatous begonia group, and that group is documented to come down with powdery mildew when the plants are continually subjected to poor air circulation and dank, stagnant conditions around the foliage, while the same plants will not endure constantly wet foliage or consistently damp roots.
How to reverse powdery mildew on Begonia Masoniana
- 1
Move the plant into a well-ventilated spot with good light but no direct sun and open a window or run a small fan so the air around the leaves does not go stagnant.
- 2
Spray affected leaves with a fungicide labelled for powdery mildew on ornamentals, covering both surfaces, then pick off and bin any badly infected leaves rather than composting them, and water only at the soil surface so the foliage stays dry.
- 3
Repot annually in spring into a free-draining mix in a shallow container that matches the rootball, since begonias do not like to swim in their pots and damp roots make mildew outbreaks far worse.
Keep powdery mildew off this Begonia Masoniana
Provide high humidity without spraying water directly onto the leaves, aim the watering can at the soil surface rather than over the foliage, keep the plant in good indirect light in a room with steady air movement, and never let the compost stay constantly wet.