What Is Begonia Pythium Rot – Managing Begonia Stem And Root Rot

Begonia stem and root rot, also called begonia pythium rot, is a very serious fungal disease. If your begonias are infected, the stems become waterlogged and collapse. Exactly what is begonia pythium rot? Read on for information about this disease and tips for treating begonia pythium rot.

What is Begonia Pythium Rot?

You may have never heard of begonia stem and root rot. If your begonias are infected, you’ll likely want to know more about it. This is a disease caused by the fungal-like organism Pythium ultimum.

This organism lives in the soil and can subsist there for long periods of time. It is likely to become active when the ground is very wet and the weather is cool. The pathogen spores travel in water and are spread when infested soil or water is transferred to healthy areas.

When begonia stem and root rot infects your plants, they are likely to show a variety of symptoms. These include darkened foliage, blackened and rotting roots, rotting stems just above ground level, and collapsing crown.

Stem and root rot of begonia usually kills seedlings by damping off. It often leads to the death of mature plants too.

Treating Begonia Pythium Rot

Unfortunately, once your plants have been infected by begonia stem and root rot, it is too late to save them. There is no product for effectively treating begonia pythium rot. You should remove infected plants from the soil and dispose of them.

However, you can make efforts to prevent stem and root rot of begonia when you are first putting in the plants. Sterilize the soil or growing medium before planting and, if you must reuse pots, sterilize these as well. Don’t plant begonia seeds too deep.

Use bleach to disinfect any garden tools you use on the begonias. To avoid infection by stem and root rot of begonias, avoid overwatering and never apply water to the leaves or set the hose end on the ground. It’s also wise to avoid fertilizing the plants too much.

Keep the plants far enough apart to allow excellent ventilation. Use fungicide but rotate the type you use regularly.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.