Twig beetles, Pityogenes spp., Pityopthorus spp.,

Fig. 91   Twig beetle boring dust can be found at entrance holes and caught at the base of the tree or branches.	Fig. 92  Egg gallery scoring the sapwood and inner bark.	Fig. 93  Twig beetle galleries.

Tree Species Attacked: Pines are the principal hosts, though a few specific species attack other conifers. Shaded branches on trees of all ages and young trees are susceptible.

Insect Description & Damage Symptoms: The adult beetles are light brown to almost black, and vary in length from 2 to 3.5 mm for the Pityogenes to a slightly smaller 1.5 to 3 mm for the Pityophthorus. The beetles attack weakened, dying, and newly felled small trees and branches. In young pine trees, they are often found in association with other serious damage agents, such as comandra blister rust and Warren's root collar weevil. Tiny spots of orange-coloured boring dust are visible on the bark at the beetle entrance holes, which are usually plentiful. Several egg galleries, each containing a female, radiate in a star-shaped pattern from a central wood chamber containing one male. The galleries score the sapwood and the inner bark.

Damage: Populations of twig beetles can build in slash from activities like spacing and pruning. When this occurs, the twig beetle can kill small trees.

Similar Damage: The plentiful, tiny spots of frass on the bark could be confused with ambrosia beetles, except the colour of ambrosia frass is white, as they bore into the wood rather than the bark.

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BC Ministry of Forests
Forest Practices Branch
P.O. Box 9513 Stn. Prov. Gov.
Victoria, BC
V8W 9C2

Section phone: (250) 387-8739
Section fax: (250) 387-2136

Last updated February 19, 2002