What is Clavibacter sp. known to cause?

Clavibacter species are recognized as pathogens that primarily cause bacterial canker in tomatoes. This particular disease is characterized by symptoms such as wilting, yellowing of leaves, and the presence of cankers on the stems of infected plants. The infection often starts at the crown or stem base and can progress to affect the entire plant, leading to significant yield losses.

Each of the other options refers to different diseases caused by other pathogens. Fire blight is caused by Erwinia amylovora, soft rot is primarily associated with various bacteria such as Pectobacterium and Dickeya, and powdery mildew is a fungal disease caused by various fungi in the order Erysiphales. Understanding the specific pathogens responsible for particular diseases is crucial for effective disease management and control in agricultural practices.