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Fire blight, a disease that attacks more than 100 species of flowering plants, fruit trees and other trees, is caused by the bacteria Erwinia amylovora. The disease usually attacks blossoms first, and then moves up through the tree, attacking the branches.

Pest of the Month: Fire Blight

By Jesse Lee


 


What does it look like?


Fire blight, a disease that attacks more than 100 species of flowering plants, fruit trees and other trees, is caused by the bacteria Erwinia amylovora. The disease usually attacks blossoms first, and then moves up through the tree, attacking the branches.


Infected flowers wilt and turn black or brown, and as the disease progresses to the branches, oozing cankers form on the tree. Fire blight can kill or severely damage infected trees.


 


Host material and range


Fire blight affects rose species and fruit trees, especially apple and pear trees, throughout the United States. The disease also affects trees like mountain ash, cotoneaster and hawthorns.


 


Current threat


Fire blight is fairly easily spread by rain, insects, birds and animals, as well as through transmission from watering or other gardening practices. Warm weather provides optimal conditions for the spread of fire blight.


Because it spreads so freely and easily, preventative measures are extremely important in controlling the disease.


 


Prevention tips


Traditionally, foliar-applied antibiotics like streptomycin or terramycin have been used to combat or prevent fire blight infestation. Another antibiotic, oxytetracycline, has been labeled for tree injection treatment. Most antibiotic treatments must be applied at the height of fire blight season, usually in the spring.


In addition to antibiotics, phosphite treatments have shown significant positive results in preventing or suppressing fire blight. Phosphites can be trunk-injected or applied topically, and, because of their long residual time, can be applied well in advance of early spring infections — allowing applicators to spread out their workload and provide early treatment.


 


Treatment tips


Trees already infected with fire blight should have the infected branches pruned, and proper care should be taken in disposing of the materials, including burning or disposal far from surrounding trees or plants. Make sure that any tools or other materials that may have come in contact with infested trees are properly cleaned and cared for.


 


Jesse Lee is with Epic Creative, Wis. Article provided by Mauget, a leader in micro-injection and micro-infusion tree care. Contact Mauget or visit www.Mauget.com to learn more about fire blight and how you can treat this and other diseases.

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