Hi Patti,

Two of the most frustrating problems to have in a collection of begonias are bacterial and virus infections. What makes these problems so frustrating is that the symptoms are hard to diagnose, there are no guaranteed ways to avoid the problems, and most times the smartest thing to do is to remove and destroy any infected plants.
Management: Bacterial pathogens can survive and reproduce on the surface of asymptomatic plant tissues. Disease symptoms develop once the pathogen reaches high population levels on the plant surface. Sanitation is especially important for bacterial pathogens.  Most fungicides are not effective against bacteria. Copper-based products are helpful in limiting populations of surface borne populations of bacterial pathogens.

Thank you for using Ask Extension.

Pam
MSUE Master Gardener