Meet fire blight: a virulent bacteria that kills leaves, stems, fruit, whole branches and entire trees. But don’t fear, our Plant Health Care Department is ready to start the year by fighting off this destructive and predictable attacker. The most important tool in your arsenal against fire blight is timing. The only available defense is a preventative treatment that should be applied before the end of February to be effective.
While many fruit trees are susceptible to fire blight, the most common victim in urban landscapes is the evergreen pear. Valued for its glossy green leaves and white blossoms that bloom before the start of spring, it is actually this early bloom that makes evergreen pears such an easy target for fire blight. Look for clusters of brown, dead leaves like in the following pictures. These are clear indicators of fire blight.
The fire blight bacterium (erwinia amylovora) remains relatively dormant in infected trees throughout the winter. But as new growth begins in the spring, the infection spreads within infected trees and from infected trees to uninfected ones, usually through splashing water or insects attracted to blossoms.
Because the infection is exacerbated by new growth, it is important not to fertilize or heavily irrigate infected trees during the warmer months. Instead, talk to your tree care company about a dual-pronged approach of topical sprays and pruning to cut out infected branches. It is exceptionally difficult if not impossible to eradicate fire blight from a tree once it has been infected, but you can maintain an attractive appearance in your trees with appropriately timed chemical treatments and proper pruning practices.
It is a fact of our modern landscape that certain trees will continue to be susceptible to particular infections, whether bacterial, fungal or pest. If you would rather not maintain a scheduled tree care regime that includes plant health care, ask your arborist to help you create a proactive plan to remove and replace susceptible trees with varieties that meet your vision for the property, whether they be aesthetic, low maintenance, water efficient, or all three.