WSU Extension


Bacterial blight 
Fire blight 
Cotoneaster webworm 
Spider mites 

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Caption: Cotoneaster fire blight
Photo by: R. Maleike
Cotoneaster : Fire blight
(revision date: 4/23/2014)

Fire blight is a bacterial disease which initially infects via flowers. Common symptoms include watersoaked spots on the bark, cankers at the base of affected twigs, and droplets of a dark bacterial ooze on the bark. Affected shoots often appear black and "scorched", wilt, and develop a characteristic "shepherd's crook" appearance as they die. The disease is easily transmitted by rain, wind, tools, and pollinating insects. Fire blight may also infect apple, pear, pyracantha, and crabapple. Bacterial blight caused by Pseudomonas may be mistaken for fire blight. Fire blight is not a problem in western Washington.
Management Options

Non-Chemical Management
  • Prune and destroy affected tissues during spring and summer. Make pruning cuts well below infected area. Sterilize tools between cuts.
  • Avoid overhead watering.
  • Fertilize moderately to prevent excessive growth of very susceptible shoots.
  • Species reported to be resistant to fire blight include Cotoneaster adpressus praecox and C. a. p. 'Boer', C. apiculatus, C. bacillaris, C. dielsianus and C. d. var. elegans, C. distica, C. foveolatus, C. franchetii, C. harroviana, C. integerriumus, C. mi
Select non-chemical management options as your first choice!

Chemical Management

None recommended


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Caption: Cotoneaster fire blight
Photo by: R. Maleike