Bad news first, then the good!
Nothing can be done to change the
course of the disease after symptoms of blossom blast appear, and no further spread of the disease will occur after bloom.
Severe outbreaks of blossom blast on pears are usually associated with spring frosts because frost injury provides entry sites for infection.
- Center for Agriculture, Food and the Environment via university of MN.
Blossom Blast is a bacterial infection - not fungal. It's everywhere in the environment, and often spreads during spring rains, commonly targeting buds after a frost nips them a bit. It infects the plant because the plant is temporarily weakened and in a cold/moist environment.
so: bad news. You'll probably lose this year's harvest. Nothing can be done about that.
Good news: You don't need to replace the trees! This bacteria generally grows on the surface of plants and the tippy tips of fragile growth (like buds and ultra-baby leaves) during cooler rainy months. Once the tree grows some more foliage, and the weather warms up a bit, it'll be fine.
Try to pamper them a bit this year to get their health/strength back up to fight off the infection early. Next year you'll be starting fresh with the same trees.
While blossom blast infections can seriously reduce a year's harvest, the infection almost never spreads to larger branches. It is generally a one-season curse, not something that persists over the plant's lifetime.
sorry for this year's harvest.
Good luck!
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