Fire blight
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May 25, 2024
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Fire blight is a common problem for homeowners with pear and quince trees, as well as apples, crabapples, and Pyracantha. The symptoms of the disease are shoots, flowers, and fruits that wilt, blacken, and die. If infections are not removed, the whole tree may die. The bacteria Erwinia amylovora overwinter in limb cankers and may grow rapidly in warm, humid conditions.
The book “Pests of the Garden and Small Farm” by the UC Division of Agriculture and Natural Resources advises treating fire blight. Cut diseased branches back about nine inches into healthy wood. Making such severe cuts may seem like butchering the tree, but it’s necessary. Sterilize pruning tools in disinfectant to avoid spreading the pathogen from one part of the tree to the next. A dilute copper fungicide can be applied during the bloom period as a preventive measure. Antibiotics, such as streptomycin and terramycin, are often used in commercial orchards.
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Katie Martin