Tomicus piniperda (Pine Shoot Beetle) - Fact Sheet

Identification

Adults are 3 to 5 mm long and cylindrical.Footnote 1 Footnote 2 Their head and thorax are shiny black while the elytra are reddishbrown to black.Footnote 3 Footnote 4 The head is visible from above. The elytral declivity is smooth and rounded.Footnote 1

Host Trees

Pinus (main host), Abies, Larix, Picea and Pseudotsuga.Footnote 1 Footnote 2

Location of Infestation within the Tree

Larvae feed on the inner bark along the bole from the root collar to the middle or lower crown. Immature beetles maturation feed and overwinter within shoots. Adults overwinter in short tunnels at the base of trees.Footnote 1 Footnote 5

Host Condition

Trees of all ages are attacked, with preference for larger standing brood trees (at least 12 cm in diameter). Dying, stressed (e.g. drought, defoliation, fire, snow) and healthy trees as well as recently cut stumps, felled trees and windthrow are preferred brood trees.Footnote 1 Footnote 5 Footnote 2 Shoot attack usually occurs above 1.8 m.Footnote 1 Footnote 6 Footnote 5

Distribution

Asia, northern Africa and Europe with introductions into eastern North America.Footnote 1 Footnote 7 Footnote 8 Footnote 9 Footnote 10

Signs and Symptoms

Breeding attacks are characterized by fine reddish-brown frass on the bark surface of trees. If relatively vigorous trees are attacked, whitish pitch tubes occur around entrance holes on the bark surface.Footnote 1 Adult beetles are associated with various species of blue stain fungi, which stain the sapwood.Footnote 1

Females construct individual monoramous, vertical (more or less) egg galleries within the inner bark that are 10 to 25 cm long and about 2 mm wide.Footnote 1 Footnote 2 Females lay eggs singly in niches on both sides of the egg gallery.Footnote 1 This species periodically sweeps its egg galleries clean of frass.Footnote 11 Larvae construct galleries, 4 to 9 cm long, that are perpendicular to the egg gallery.Footnote 1 Footnote 2

Immature beetles bore through the outer bark, creating round exit holes about 2 mm in diameter.Footnote 1 Footnote 10 Beetles then fly to the crowns of live, healthy pines of all ages and usually maturation feed on the current year's shoots.Footnote 1 Footnote 2 Beetles tunnel into the centre and bore outwards, hollowing out 2 to 10 cm of the shoot.Footnote 1 Shoot feeding does not kill the tree but causes reductions in height, diameter and volume.Footnote 1 Footnote 12 Damaged shoots display a round entrance hole (2 mm) and either one hollowed gallery or several short hollow galleries, which are usually surrounded by pitch. Damaged shoots are disfigured, turn yellow then red, droop, become dry and brittle, and eventually break off near the entrance hole.Footnote 1 Footnote 6 Footnote 2 After windstorms, branches break off and the tree appears pruned.Footnote 3

In late October to November the adult beetles move down the tree to the base of the trunk where they bore into the bark to overwinter.Footnote 2

Adult Tomicus piniperda (3-5 millimetre long) tunnelling in a shoot.

A - Adult T. piniperda (3-5 mm long) tunnelling in a shoot.

Tomicus piniperda egg (10-25 centimetre long) and larval (4-9 cm long) galleries. Note vertical orientation of egg galleries.

B - T. piniperda egg (10-25 cm long) and larval (4-9 cm long) galleries. Note vertical orientation of egg galleries.

Pitch tube surrounding entrance hole on brood tree.

C - Pitch tube surrounding entrance hole on brood tree.

Round entrance hole (2 millimetre wide) on infested shoot.

D - Round entrance hole (2 mm wide) on infested shoot.

Green flagging on shoot caused by maturation feeding.

E - Green flagging on shoot caused by maturation feeding.

Frass expelled from Tomicus piniperda entrance holes.

F - Frass expelled from T. piniperda entrance holes.

Red flagging caused by maturation feeding within current year's shoot.

G - Red flagging caused by maturation feeding within current year's shoot.

 

Photo credits

  • A Gyorgy Csoka, Hungary Forest Research Institute, Image 1231204, www.invasive.org, April 4, 2004
  • B William M. Ciesla, Forest Health Management International, Image 0017008, www.invasive.org, March 14, 2004
  • C Stanislaw Kinelski, Image 1258125, www.forestryimages.org, May 22, 2004
  • D Gyorgy Csoka, Hungary Forest Research Institute, Image 1231203, www.invasive.org, April 6, 2004
  • E Bruce Smith, USDA APHIS PPQ, Image 0805094, www.invasive.org, April 5, 2004
  • F Stanislaw Kinelski, Image 1258126, www.forestryimages.org, May 22, 2004
  • G Robert A. Haack, USDA Forest Service, Image 3225083, www.invasive.org, April 4, 2004
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