Population Dynamics, Route of Infection, and Velocity of Systemic Spread of in Infected Apple Branches.

Fire blight, caused by , is one of the most devastating diseases of apple and pear worldwide. Young trees are particularly susceptible to the shoot blight phase of the disease, and the rapid downward spread of from infected shoot tips throughout trees to the rootstock often results in the formation of girdling cankers that kill trees. We quantified and tracked the systemic migration of cells in field studies through infected shoot tissues to gain insight into the systemic movement of the pathogen.