Ips engraver beetles in the United States: what the forest services and extension record
What the Texas A&M Forest Service, the Colorado State Forest Service and Utah State University Extension say about Ips engraver beetles: the species named, the pine and spruce hosts, the galleries, the stress and fresh-wood conditions the sources link to attacks and how they compare with other bark beetles.
Checked against the sources at the bottom of this page on October 9, 2026. Rules, fees and pay change: the source has the last word.
This page describes what the named sources say. It is not a diagnosis of any tree and does not say what should be done with one. None of the three pages read lists Ips engraver beetles as regulated or notifiable. Each section names its source, all read on October 9, 2026. The group has a row in insect pests of trees, which compares it with the other bark beetles and pests listed there.
Names and what the sources call them
The Texas A&M Forest Service says Ips bark beetles are also known as pine engraver beetles and describes them as small, cylindrical, brown to black insects that feed and lay eggs in the inner bark of pine trees. The Colorado State Forest Service uses the name ips beetle, adds that they are also called engraver beetles, and describes bark beetles that live and tunnel beneath the bark of pine and spruce, injuring and killing the tree. Utah State University Extension has a page headed pine engraver. The sources therefore differ on the group name, and the species differ by region.
Species and sizes as the sources give them
| Source and region | Beetle and size | Where on the tree |
|---|---|---|
| Texas A&M Forest Service, East Texas | Eastern six-spined engraver, Ips calligraphus, about 5 mm. | Large-diameter material such as the trunk or large branches. |
| Texas A&M Forest Service, East Texas | Eastern five-spined engraver, Ips grandicollis, about 4 mm. | Medium-sized material such as the upper trunk and large branches, or small-diameter trees. |
| Texas A&M Forest Service, East Texas | Small southern pine engraver, Ips avulsus, about 3 mm. | Almost always branches in the tops of trees. |
| Colorado State Forest Service | Ips beetles of 1/8 to 3/8 inch, reddish brown to black, similar in appearance to the mountain pine beetle. | Under the bark of pine and spruce. |
| Utah State University Extension | Pine engraver adults of about 1/6 inch, reddish brown to black, with a concave rear end surrounded by four prominent spines. | Phloem of ponderosa, Jeffrey, lodgepole and jack pine and other stressed pines; trees killed from the top down. |
Texas A&M says all three of its species infest and kill southern yellow pines and that it is not uncommon to find all three in one tree. It says the species are told apart by the number of spines on each side of the abdomen and the part of the tree they use.
Galleries and signs
Texas A&M says the beetles build vertical egg galleries shaped like the letters Y, H or I, from an inch or two to over a foot long, etched into the inside of the bark and the outer sapwood, and calls them the easiest way to identify engraver attacks. It says the small southern pine engraver also makes an unbranched I-shaped gallery, and that if only that species attacks, the top of the crown may die while the lower limbs stay alive. Colorado says mature beetles tunnel and produce a yellowish- or reddish-brown boring dust that collects in bark crevices or at the base of the tree, that small round exit holes show the beetles have finished developing in that part of the tree, and that woodpeckers may indicate infestation. Utah lists pitch tubes and sawdust-like frass and says males mate with several females, producing a diagnostic gallery pattern. Colorado and Texas A&M both say the signs resemble those of other bark beetles. Texas A&M compares the winding S-shaped galleries of southern pine beetle with the engraver Y, H and I patterns; see southern pine beetle and mountain pine beetle.
Life cycle
Utah says the beetles mostly overwinter as adults under bark, in limbs or in duff, emerge in early spring when temperatures pass 50 degrees Fahrenheit, have two to three generations a year, and that the larvae are the damaging stage. Texas A&M says generations overlap, that one can take as little as 21 days when summer temperatures consistently reach the 90s, and that East Texas typically sees five generations of bark beetles a year. Colorado gives no generation count.
Conditions linked to attacks
Texas A&M says engraver beetles do not usually kill a significant number of pine trees but breed harmlessly in fresh logging debris and weakened trees, that they are rarely the sole cause of a death, and that attacks are usually scattered with only a few trees involved. It says stands with drought, fire damage, storm damage or other disturbance are more likely to see mortality, that in extremely rare cases Ips can infest a thousand or more trees in a short period, and that even then not all infested pines die. Colorado names two factors in that state: prolonged drought stress and freshly cut wood, which it calls the preferred breeding site. Utah describes the pine engraver as able to introduce fungal pathogens. Texas A&M also cautions that fall needle flags and a dying lower branch are normal in pines and do not on their own indicate bark beetles, and that a crown whose upper third or half has turned red is likely to have been attacked by engraver beetles.
Status and where to ask
None of the three pages names a quarantine or a report line. Texas A&M tells readers to connect with a local forester or a certified arborist for concerns, and Colorado links a quick guide to the piñon ips beetle. This page gives no treatment steps, product names, rates or timings. For who may apply pesticides see pesticide licences.