? bacterial blight on chrysanthemum

 One stem of a chrysanthemum plant has had the leaves turn brown and
collapse. The browning started with leaves at tha tip of the stem and in
each leaf from nearest the stem spreading along the veins. Google has
thrown up a reference to bacterial blight but there does not seem to be
much info around suggesting that it is not common. Has anyone else had
this problem ?

Thanks

Paul
SW London