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Extension > Garden > Diagnose a problem > What's wrong with my plant? > Evergreen Trees and Shrubs > Spruce > Frass on trunk

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Spruce > Trunk or branches > Frass on trunk

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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
2 of 2
  • Image: Spruce beetle 1
  • Image: Spruce beetle 2
  • Image: Spruce beetle 3

Spruce beetle
Dendroctonus rufipennis

  • Found in stands 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
  • Adult beetles are 1/4 inch long and black to reddish-brown; larvae are small, white legless grubs

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