The angel winged begonia is a favorite among flower gardeners and landscapers. An eye-catcher, this begonia gets its name from its unique leaves that resemble outstretched angel wings. The angel winged begonia is a tropical plant that needs high humidity, adequate air circulation, full sun and lots of water to thrive. When these needs are not met, the plant becomes more susceptible to disease.
Begonias afflicted with this fungal disease first develop circular spots of what looks like white powder. As the fungus multiplies, the spots grow larger until the plant looks like it is covered with the powdery dust. Control powdery mildew by pruning the affected foliage as soon as possible. Even a mild case of powdery mildew can injure an angel winged begonia. Once the affected foliage and any leaf litter has been removed, spray the plant with a fungicide prescribed for use on powdery mildew.
Botrytis is a fungal disease that causes splotches of the angel winged begonia to become soggy and brown. If left untreated, these soggy brown areas will spread and eventually kill the begonia. Botrytis is a sign that you need to prune the interior of your plant to improve air circulation and stop overhead watering. To control the spread of the disease, prune the brown area out of the plant or cut off the affected cane, then sterilize the cut with methylated spirits. Finally, remove any dropped leaves or flowers--they may harbor fungal spores.
Bacterial Leaf Spot
Bacterial leaf spot causes small, pimple-like spots to develop on the angle winged begonia's leaves. Close inspection under a bright light will reveal that the pimples appear transparent. As the disease progresses, the small spots will spread and run together, and a slimy ooze will emanate from any cuts or wounds in the plant. Mild infections can be controlled by pruning infected tissue, but heavily infected plants should be uprooted and thrown away.
Stem rot is caused by a fungus that enters the crown of the begonia through a wound in the plant. Once established inside the plant tissue, it eats away at it, making it soft and unable to support the weight of the plant. The stems will eventually collapse. There is no cure for stem rot. Infected plants should be discarded as soon as possible to stop the spread of the disease.