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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Mountain Ash > Cracks in trunk or branches

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Mountain Ash > Trunk/Branches > Cracks in trunk or branches

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  • Image: Fireblight 1
  • Image: Fireblight 2
  • Image: Fireblight 3

Fireblight
Erwinia amylovora

  • Branch cankers have dark, sunken & cracked bark, sapwood is streaked reddish brown
  • Drops of sticky honey colored liquid can be seen on infected plant parts in warm wet weather
  • Infected leaves wilt, turn gray then dark brown
  • Young shoots bend over forming a "shepherd's crook"
  • Infected blossoms first turn gray, then black
  • Infected leaves & blossoms remain attached to the tree, often even in winter
  • Infected fruit are shriveled and discolored
  • More information on Fireblight...
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  • Image: Frost canker 1
  • Image: Frost canker 2
  • Image: Frost canker 3

Frost canker

  • Vertical splits or sunken dead areas of trunk or branches that are primarily on the south and southwest side
  • Occurs during winter, often noticed early spring
  • More information on Frost cankers...
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  • Image: Branch cankers 1
  • Image: Branch cankers 2

Branch cankers
Botryosphaeria dothidea

  • Leaves on girdled branches wilt, die and turn brown
  • Small blister like spots on branches exude, watery fluid
  • Branch infections grow to cracked, flakey, orange canker
  • Sunken brown spots on fruit, can grow to rot part or all of fruit
  • More information on Branch cankers...

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