Red Turpentine Beetle

Taxonomy

Domain	Eukarya
Kingdom	Animalia
Phylum	Arthropoda
Subphylum	Hexapoda
Class	Insecta
Subclass	Pterygota
Infraclass	Neoptera
Order	Coleoptera
Suborder	Polyphaga
Infraorder	Cucujiformia
Superfamily	Curculionoidea
Family	Curculionidae
Subfamily	Scolytinae
Tribe	Hylurgini
Genus	Dendroctonus

Scientific Name

Dendroctonus valens

Common Name

red turpentine beetle

Compiled by Whitney Cranshaw, Colorado State University:
Dendroctonus valens LeConte
Coleoptera: Scolytidae

Hosts

Most species of pine (Pinus species), especially older, large-diameter trees. Spruce (Picea species) are sometimes, although rarely attached by this species of bark beetle.

Damage and Diagnosis

Red turpertine beetle damage.

Pines and, rarely, other conifer species are sometimes attacked by the red turpentine beetle. Trees scorched near the base by fire or injured during construction are particularly susceptible. Turpentine beetle attacks are characterized by large, pinkish-purple pitch tubes confined to the lower few feet of the trunk. Beetles may be active throughout the warmer months, peaking in mid-summer.

Inner-bark feeding by red turpentine beetles does not produce a branched gallery pattern typical of most bark beetles. Rather, the adults make short, irregular tunnels and developing larvae feed as a group, excavating a irregular, round-edged patch under the bark (resembles the outline of a puffy cloud). Trees can survive attack, but resultant weakening can make hosts more susceptible to other bark beetles.

The red turpentine beetle is the largest bark beetle found in the region. They generally resemble other Dendroctonus species (e.g., mountain pine beetle) but are wine red and about 1/4 to 3/8 inch in length. Larvae, found under the bark, are legless cream-colored grubs with brown heads, somewhat C-shaped and up to 3/8 inch long.

Life History and Habits

Red turpentine beetle larvae.

Turpentine beetles favor large declining or injured trees. Pines scorched by fire, wounded by construction equipment or suffering from soil compaction and grade changes are common targets. They bore into the lower trunks, where large pink masses of resin, called pitch tubes, form at attack points. The adult beetles lay clusters of eggs within their tunnels, and when these hatch the larvae feed in groups, consuming irregular areas of cambium/phloem just under the bark. These areas may join each other and girdle the tree depending on the density of attacks. Adult attacks occur through the warm months. There are two to three generations per year.

Management

Cultural practices promoting tree vigor and preventing basal trunk wounds (hay bales surrounding trees on construction sites, for example) can help prevent attacks by red turpentine beetle. Preventive insecticide sprays (carbaryl) applied before adult attacks, are also effective.

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