Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow. Fire blight affects members of the rose family – that means apples, pears, and plums. It is caused by a native, not introduced, bacterium that overwinters cankers and becomes active when spring brings warm temperatures and rain. Bees actually spread it from flower to flower and It causes plants to die back from the terminals – often the branch tip looks like a shepherd’s crook. Although we think of Bradford pear trees as having been brought here as ornamentals, actually the first Callery pear species were brought to the US to help combat a horrible infestation in pear orchards in the western states. Thousands of seeds were collected in Japan, Korea and China and planted on government research sites in both Oregon and Maryland to identify resistant varieties. Those selected individuals were eventually used as rootstock for commercial grown pear trees.