Fire blights on Bartlett pear tree #633428 - Ask Extension


Fire blights on Bartlett pear tree #633428

Asked May 09, 2020, 2:22 PM EDT

What can I spray on the other pear and apple tree to ensure they will not get infected?

Clatsop County Oregon

Expert Response

Fire-Blight is caused by a bacterium that overwinters in cankers on infected trees.  Pruning tools and splashing rain spread this bacterium.  A temperature of 65 degrees or higher for 24 hours plus a trace of rain is necessary for the infection.  Insects such a as aphids, ants, flies, wasps, and leafhoppers can spread the disease.  

For cultural control; remove and burn all traces of blight.  Be sure to soak cutting tools in 10% Clorox solution or rubbing alcohol or Pine-sol after every cut to keep from spreading the bacterium.  Cut 4 to 6 inches beyond discoloration.

Dormant sprays of copper compounds plus oil can delay or reduce inoculum production in cankers missed after normal pruning.  Regular bactericide sprays during main bloom season are effective.

Consult your local nursery for these products and, as always, read and follow the label instructions completely.

Thank you for your question.

Linda Holmes Replied May 13, 2020, 5:25 PM EDT

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