What you need to know about this pest

spruce bark beetle
Images of the spruce bark beetle, an affected tree, and a beetle larval gallery. Images from U.S. Forest Service.

It’s hard to scan a forested hillside and see those dead spruce trees in among the green-leafed deciduous stands. The U.S. Forest Service and the Alaska Division of Forestry have good information on their websites about the spruce bark beetle. We’ll share those resources, and speak with foresters about this pest’s life cycle, how widespread the reach is in Southcentral Alaska, and what advice they offer for the homeowner on how to protect their own trees.

Here’s some of what we found out, from the Alaska Div. of Forestry:

  • spruce bark beetles are less than a quarter inch long
  • they infect Sitka, white and Lutz spruce, but rarely black spruce
  • they live in the thin phloem, or growing area, between the bark and the wood
  • a female can lay 10 to 150 eggs in galleries beneath the bark
  • when temperatures are above 60-degrees in mid-May through mid-July, the beetles fly to new host trees
  • they thrive on wind-thrown, fallen or injured trees
  • since the mid-1970s, these beetles have affected about 50 percent of the Kenai Peninsula’s forested land

Thanks for listening!


HOSTKathleen McCoy


  • Stephen Burr, forest entomologist, U.S. Forest Service
  • Jason Moan, Forest Health Program, AK Div.of Forestry



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  • LIVE: Monday, August 13, 2018 at 2:00 p.m.
  • REPEAT: Monday, August 13, 2018 at 8:00 p.m.