Bark Beetles
Red Turpentine Beetle
Dendroctonus valens (LeConte)

Hosts:  Pines

Figure 114. Figure 114. Large pitch tubes at bases of ponderosa pine indicate red turpentine beetle attacks.

Symptoms/Signs:  The best indicators of red turpentine beetle attack on pines are: large pink-white pitch tubes on the lower bole; accumulations of reddish brown sawdust at the base of the tree and in bark crevices; and accumulations of cream to pink colored crystallized resin granules at the tree base. The egg galleries under the bark are fairly wide and linear to irregular in shape. Galleries extend downward from the entry hole 7 cm to 1 m and may even extend into large roots.

Adults are reddish brown, cylindrically shaped beetles approximately 8 mm in length. Larvae are white, legless grubs.

Figure 115. Figure 115. Red turpentine beetle frequently attacks fire-damaged ponderosa pine as indicated by pitch tubes and frass.

Biology:  The number of generations varies from 1 to 2 years in the coldest portions of its range to 2 to 3 generations per year in the warmest areas. Attacks are made in the lower bole of pines. Attacks occur throughout warm weather but peak by midsummer. These beetles often attack trees scarred by fire.

Effects:  Through repeated attacks this beetle can sometimes kill trees; however, more often it weakens trees, predisposing them to fatal attack by other bark beetle species. In successful attacks, a patch of bark ranging from a few square cm to a square m or more may be killed. Red turpentine beetles frequently colonize fire-scorched ponderosa pines.

Similar Insects and Diseases:  This beetle is distinguished from other bark beetles by the large size of the pitch tubes, galleries and the beetle itself.

References:  2, 24, 95

Figure 116a. Figure 116a. Granola-like crystallized resin material can occur around bases of pine trees attacked by red turpentine beetle.
Figure 116b. Figure 116b. Granola-like crystallized resin material can occur even below the soil on primary roots.
Figure 117. Figure 117. Egg and larval galleries of red turpentine beetle. Note that larval feeding occurs in a gregarious fashion.
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