ABSTRACT
Thomas J. Burrill initiated phytobacterioiogy when he asserted that fire blight in pear was not caused by a fungus, but by a bacterium. In 1878 he wrote that in “the mucilaginous fluid from the browned tissue under microscope, the field is seen to be alive with moving atoms known in a general way as bacteria. When E. amylovora cells are needle inoculated into a host’s shoot, they apparently lie just as they were distributed throughout the puncture for the first 30 to 45 min. Approximately 1 hour after inoculation, the bacteria appear to be embedded in a jelly-like substance that is somewhat irregular in shape. The bacteria multiply in the jelly-like mass on the margin of the puncture among the lacerated cells, forming a biomass that invades the intercellular spaces of the cortical region, about ten cells proximal to the epidermis. The intercelluar spaces are large in this parenchymal tissue.
