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Pine Shoot Borer

Characteristics:

  • Eggs: Elliptical-shaped eggs are yellowish and about .3 millimetres in diameter. They are hard to see if laid on the needle sheath.
  • Larvae: Larvae are rarely seen as they tunnel into branches to eat the pith. Larvae have dirty white bodies and dark heads. They can grow up to 13 millimetres in length over a period of 42 to 55 days. When fully grown, the larvae chew an exit hole from the branch and drop to the ground.
  • Adults: Adult moths emerge anytime from late April to early June. Their forewings are coppery-red with 2 dark grey bands; their hind wings are grey brown.

Identifying infestations:

  • Weakened shoots or branches: Larvae tunnel into a branch where it joins the trunk to eat the wood (pith.) However, the bark is left intact. The weakened shoot drops or breaks.
  • “Shaved” or red needles along branches: Larvae stunt or kill needle growth in trees as they tunnel into a branch to eat its pith. This action causes needles to appear “shaved” closer to the trunk and “longer” at the end of the branch. Needles may also fade or turn red.

IPM Toolkit:

  • Preventive tools:
    • The borer attacks fast growing pines more than slow growing pines.
  • Physical tools:
    • Prune infected branches.
  • Biological tools: Not applicable
  • Least toxic chemical tools: Not applicable