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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Deciduous > Basswood/Linden > Unusual color on branch or trunk

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Basswood/Linden > Trunk/Branches > Unusual color

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  • Image: Lichens 1
  • Image: Lichens 2
  • Image: Lichens 3

Lichens
Several species

  • Colorful patches on the bark of trunk and/or branches
  • Can be wrinkled, in scalloped sheets, lace-like pads, bushy tufts, paint-like spots or splashes
  • Forms can be flat against the bark surface or raised in leaf-like lobes, finger-like or hairy projections
  • Colors may be shades of gray, green, blue, yellow, orange, or red
  • More information on Lichens...
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  • Image: Perennial nectria canker 1
  • Image: Perennial nectria canker 2
  • Image: Perennial nectria canker 3

Perennial nectria canker
Neonectria galligena

  • Sunken dark brown cankers on main trunk or branches
  • Cankers become crater like cavities with age
  • Red to reddish orange raised cushion like bumps can occasionally be seen on the edge of the canker
  • Dead branches and twigs killed by girdling cankers
  • More information on Perennial nectria canker...
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  • Image: Branch cankers 1
  • Image: Branch cankers 2
  • Image: Branch cankers 3

Branch cankers
Botryosphaeria obtusa and other fungi

  • Cankers are brown to black sunken areas on branch that may have cracked bark and discolored sapwood
  • Leaves on random branches wilt, turn yellow then brown during the growing season
  • Random dead branches seen throughout canopy
  • Infected branches don’t leaf out in spring
  • Common on trees stressed by drought, winter injury, wounds, insect feeding or other factors
  • More information on Branch cankers...
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  • Image: Sooty mold 1
  • Image: Sooty mold 2
  • Image: Sooty mold 3

Sooty mold

  • Black, brown, or gray soot-like covering on leaf surfaces, or twigs
  • Sticky, shiny secretions on leaves from sap-sucking insects (aphids, leaf hoppers, psyllids, etc.)
  • Insects or signs of insect damage (distorted, pin-prick feeding marks, etc.) may be seen on leaves above the worst affected moldy areas
  • More information on Sooty mold...

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