Asian pear trees with brown, curling leaves are most likely infected with fire blight bacteria and can be treated with white vinegar, according to SF Gate. Spraying the plant every two weeks with a solution of 6 cups water and 4 cups white vinegar should bring the infection under control. All diseased limbs must be removed, using a shears dipped in chlorine bleach, to prevent the bacteria from spreading.Continue Reading
Copper products are the only fire blight treatment available to residential customers, and these don't provide adequate control over fire blight even with multiple applications, according to the University of California at Davis. New tissue is especially vulnerable, so it's best to avoid excess fertilization and heavy pruning, which encourage growth.
The best defense against fire blight is aggressive pruning and choosing tolerant varieties of plants. Removal of infected branches should be done in summer or winter, with dead branches removed to at least 100 feet away from the tree. Fast-moving infections should be removed as soon as they appear in spring. Cuts should be made with enough space around the canker to ensure that all infected tissue is removed. Asian pears, with the exception of Shinko, are very susceptible to fire blight. Less-susceptible pear trees include Bradford, Capitol and Red Spire. Young trees are generally more susceptible than mature ones.Learn more about Trees & Bushes