Pear Tree Fire Blight

Fire blight is a bacterial disease caused by Erwinia amylovora that attacks members of the Rosaceae family - especially pear and apple - and is active in North American home orchards from zones 3-11; it commonly infects during bloom when bees and insects move bacteria from flower to flower, and when rain or heavy dew help bacteria move into nectaries, so watch trees the way you would common orchard hosts like apples during bloom.

Timing matters: infections are most likely during warm, wet stretches in spring bloom and can continue into early summer on young, succulent shoots. After bloom, the bacterium can overwinter in branch cankers that later serve as infection sources. Routine seasonal checks at bloom and again in early summer let you catch new strikes early and avoid bigger problems later.

Fire blight is bacterial, not fungal, which changes management: fungicides do not control it, and sanitation plus physical removal of infected tissue plus targeted biological or chemical tools are the primary home-garden options. Compare disease patterns carefully because fungal leaf spots, quince rust, or frost damage can look superficially similar but require different responses; for a closer comparison of orchard hosts read the contrast between apple and pear susceptibility where it helps explain why pears often show faster collapse.