Pine

Not known to transmit any human or animal pathogens.

Several fungi have been isolated from Ips sexdentatus, including some pathogenic ophiostomatoid blue stain fungi, but their status as a vector of pathogenic fungi to living trees remains unclear. See the CAPS Datasheet for additional information.

When trapping for woodborers or bark beetles, separate traps with different lure combinations by at least 30 meters (98 feet).

Look for areas with no other plants below the trap. Traps should be spaced at least 250 ft. from each other at a height of 5 to 6¹/₂ ft. above the ground.

The release rate of this lure is highly temperature dependent. However, CAPS has listed a conservative length of effectiveness of 56 days (8 weeks) that will be effective for even the warmest climates in the CAPS community.

Attacked trees may show obvious discoloration of their crowns, yellowing needles, branch dieback, entrance holes, frass or sawdust expelling from the holes, and resin flow. Infestation can also lead to infection by fungal pathogens that cause blue staining on the bark or wood. Note that these symptoms are general to many bark beetles and see the CAPS Pest Datasheet for images of infested trees.

The galleries formed by Ips bark beetles are characteristic for the genus. Ips sexdentatus females create multiple galleries along the trunk where they will deposit eggs, that often form a Y- or X-shaped pattern (see Fig. 5 in the Pest Datasheet).

A Likelihood of Establishment Map is now available. This survey should only be considered in the states with appropriate conditions and suitable hosts for this insect.

The map was produced by the SAFARIS Team. SAFARIS is a modeling framework that enables PPQ to quickly respond to emergencies, efficiently survey for pests, and assess potential pest impacts by collecting critical geospatial data and developing predictive models. SAFARIS is developed and maintained by the NC State University, Center for Integrated Pest Management (CIPM) with support from PPQ PPRA.

Surveys should take place when the temperature is 63°F or above, when flight activity is more likely to occur

Survey for I. sexdentatus in Pinus spp. forests and/or managed areas grown for timber. If other, less preferred host genera (i.e., Abies, Larix, Picea) are present and economically relevant, they can also be surveyed.

Ips sexdentatus infestations are typically unevenly distributed and patchy throughout the forest and could concentrate along forest edges. Surveyors should place traps across survey sites in an attempt to cover most of the area and should trap near forest edges and roadsides.

Any accumulation of dead or dying wood could attract I. sexdentatus, allowing populations to rapidly expand. For example, forests that have recently experienced a climatic or biotic event such as a hurricane, windstorm, fire, drought, or disease are an ideal target for survey because I. sexdentatus prefers to colonize the fallen or dying trees. Similarly, any forests with piles of cut logs present are a good target for survey because I. sexdentatus will readily attack this material and populations of the beetle may grow quickly.

Visual inspection is only useful to guide trap placement. Areas with dying trees, fallen trees, or piles of cut logs are ideal breeding sites for the beetles.

Morphological: Examine specimens under a good quality, high powered (preferably with up to 90X) dissecting microscope, with the help of a reference collection. Use screening aid for relevant geographical area.

Douglas et al. (2019) provides a dichotomous key to Ips bark beetles of the world with illustrations. This key is also available online at Key to the world species of Ips (Coleoptera: Curculionidae: Scolytinae) (lucidcentral.org).

There is a screening aid for I. sexdentatus available from the Identification Technology Program (ITP) by Joseph Benzel from 2015.

University of Florida IFAS Extension Datasheet for Ips sexdentatus

Bark and ambrosia beetles of the Americas provides images and information for native bark beetles, including native Ips species.

Ips sexdentatus can be confused with I. calligraphus (six-spined engraver beetle) and I. apache; they are present in the United States and have Pinus spp. as their main host. Ips calligraphus is present throughout the continental United States, while I. apache is only reported in Arizona.

All Ips species mentioned above have six spines in the concave apical part of the body. However, I. sexdentatus can be differentiated from other species by having the fourth one as the largest spine, while the others have the largest spine in the third position.

In the United States, other Ips species that may be found in traps and are most likely to be confused with I. sexdentatus include: I. bonanseai, I. borealis borealis, I. confusus (Pinyon pine beetle), I. cribricollis, I. grandicollis (five-spined engraver beetle), I. integer, I. knausi, I. paraconfusus (California five-spined ips), I. perturbatus (northern spruce engraver), and I. pini.

The screening aid provided in the Identification Resources section above mentions that during I. sexdentatus surveys in the United States the Ips species often captured include I. calligraphus, I. plastographus, and I. montanus.