Mountain Pine Beetle -
Dendroctonus ponderosae

Mountain Pine Beetle larvae, 1/8 - 1/4 inch Beetle larvae trapped in pitch tube                    Mountain Pine Beetle larvae, adult 1/4 inch
Scott Tunnock, USDA Forest Service,                                         USDA Forest Service,
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Pitch tubes on tree trunk  mountain pine beetle galleries
Mark McGregor, USDA Forest Service,    Leslie Chong, Simon Fraser University,
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HOSTS: All native and introduced species of pine.

DESCRIPTION: Adult beetles are cylindrical, stout bodied beetles, about 1/4 inch long, and brown to black in color. The larvae are white-yellowish, legless grubs with a dark head.

LIFE CYCLE: Larvae spend the winter under the bark. They feed throughout the spring and then pupate in early summer. Depending on the species of host tree the beetle will emerge in mid to late summer to attack new host trees. After they mate the female forms a vertical tunnel and lays about 75 eggs. When the eggs hatch, the larvae tunnel away from the egg gallery which produced a characteristic pattern in the wood. Look for pitch tubes and red boring dust in bark crevices and on the ground.

CONTROLS:

Cultural: Woodpeckers and clerid beetles feed on Mountain pine beetle adults and larvae. Do not allow trees to become overcrowded. Keep trees watered during July and August. Maintain pH at <6.5; mulch with composted fir or pine bark 1 - 2 inches deep. Remove and destroy infested trees.

Chemical: Carbaryl (liquid formulation) can be applied to tree trunks 30 - 35' high before May first. One treatment is good for two seasons.

Trapping - Anti-aggregation pheromone see Bark Beetle Pheromone Use Table.


Missoula County Extension Office; Missoula, Montana 59808 - Updated for 2006