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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Evergreen Trees and Shrubs > Spruce > Dead branches or leader

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Spruce > Trunk or branches > Dead branches or leader

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  • Image: Cytospora canker 1
  • Image: Cytospora canker 2
  • Image: Cytospora canker 3

Cytospora canker
Leucostoma kunzei

  • Needles on one or more branches turn completely brown or purplish brown then fall off
  • Scattered dead branches occur throughout the tree, often starting on the lower branches and then spreading upward
  • Clear to white resin encrusted cankers on infected branches
  • Common on Colorado blue spruce, or very stressed spruces
  • More information on Cytospora canker...
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  • Image: White pine weevil 1
  • Image: White pine weevil 2
  • Image: White pine weevil 3

White pine weevil
Pissodes strobi

  • Terminal leader dead or dying, curled into a shepherd’s crook
  • Branches in whorls near the top may also wilt and die
  • Repeated attacks can leaves trees looking bushy
  • Drops of pitch can be seen on terminal shoots in spring
  • Larvae are whitish, legless and up to 2/5 inch long
  • Adults are 1/4 inch long, brown body with patches of white and orangish brown scales
  • More information on White pine weevil...
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  • Image: Spruce beetle 1
  • Image: Spruce beetle 2
  • Image: Spruce beetle 3

Spruce beetle
Dendroctonus rufipennis

  • Most commonly reported in older white spruce in northern Minnesota, particularly along the North Shore
  • Prefers larger trees, 12 inch diameter trees or larger
  • Needles discolor yellowish green to reddish brown
  • Reddish brown sawdust around exit holes and on the bark and on the ground
  • Pitch tubes develop around exit holes
  • Trees eventually die
  • Beetles can build-up populations in trees knocked down in wind or ice storms
  • Adult beetles are 1/4 inch long and black to reddish-brown; larvae are small, white legless grubs
  • More information on Spruce beetle...
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  • Image: Northern spruce engraver beetle 1
  • Image: Northern spruce engraver beetle 2
  • Image: Northern spruce engraver beetle 3

Northern spruce engraver beetle
Ips perturbatus

  • Reddish brown frass around exit holes and on the bark and on the ground
  • Found mostly on white spruce in plantations, rarely in home landscapes
  • Needles discolors to yellowish-green to red, branches can die back
  • Creates distinctive galleries under bark
  • Adult
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  • Image: Small spruce weevil 1
  • Image: Small spruce weevil 2
  • Image: Small spruce weevil 3

Small spruce weevil
Pissodes rotundatus

  • Found mostly in spruce plantations, rarely in home landscapes
  • Needles discolor yellowish green to reddish brown
  • Can find woodpeckers attacking infested trees
  • Often found in dead or dying spruce, they are generally regarded as secondary invaders, they are not often the cause of tree death
  • Chip cocoons are diagnostic for this weevil (found under bark)
  • Adults are 1/4 inch long, dark brown to black body
  • Larva is small legless whitish grub

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