- X. vasicola pv. vasculorum appears to overwinter in infected crop residue from the previous growing season.
- Bacteria move from residue onto living plant tissue via rain splash. Bacteria can enter the plant through stomata or wounds.
- Symptoms often appear on the bottom leaves of a plant and spread upwards.
- Spread of secondary infection upwards through the canopy, from plant to plant, and into adjacent fields is facilitated by overhead irrigation or wind-driven rain.
Photo: Mike Wardyn; near Elsie, NE June 26, 2018