Trypodendron spp; also Platypus, Gnathotrichus, and Xyleborus

Hosts - True firs, spruce, Douglas-fir, hemlock, larch, and pines.

Damage - Small diameter (one-sixteenth inch or less) holes are bored straight into tree, perpendicular to bole. Weakened, dying, or recently cut or killed trees are attacked. Galleries within the sapwood cause defect in logs. Some species extend galleries into the heartwood, and freshly cut lumber may be attacked before it has dried.

Identification - Entrance points (pinholes) are marked by piles of fine, granular, white boring dust in bark crevices. The main entrance gallery of Trypodendron penetrates sapwood from 1 to 2 inches before branching. Tunnels with brood chambers branch in a horizontal plane and cut across the grain of the wood. Holes and galleries are surrounded by a dark brown or black fungus stain. Adult Trypodendron are stubby, one-eighth to three-sixteenths inch long, and are generally shiny and dark brown to black.

Other genera have different body shapes, gallery dimensions, gallery patterns, and life cycles.

Similar damages - May be confused with other bark beetles; however, ambrosia beetles are the only ones which bore straight into bole producing fine, white boring dust.

Management - Since Ambrosia beetle damage is confined to moist unseasoned wood, no forestry treatments are warranted other than to maintain a vigorous growing stand of trees.