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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous Trees > Ash > Sunken circular to irregular area on main trunk

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Ash > Trunk > Sunken circular to irregular area on main trunk

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  • Image: Smooth patch, multiple tree trunks
  • Image: Smooth patch, tree trunk
  • Image: Smooth patch, bark up close

Smooth Patch
Aleurodiscus sp. Dendrothele sp.

  • Sunken, relatively smooth, round to irregular area of bark on trunk or branches
  • Affected bark is often lighter in color
  • Small cream colored disks or saucer like fungal spore producing structures grow within affected area
  • Has no affect on the overall health of the tree
  • More information on Smooth Patch
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  • Image: Nectria canker, canker up close
  • Image: Nectria canker, large canker on trunk
  • Image: Nectria canker, reddish bumps around canker up close

Perennial Nectria canker
Neonectria ditissima

  • Sunken round to oval cankers with target shaped ridges of barkless wood on large branches or the main trunk
  • Small dark sunken area on twigs that can girdle and kill the branch
  • Red to reddish orange raised cushion like bumps can occasionally be seen on the edge of the canker
  • More information on Perennial nectria canker

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