Beetle – Bark beetles

Common Name: Beetle – Bark beetles
Latin Name: Ips, Scolytus, and Dendroctonus.
Common Family Name: Bark beetles
Latin Family Name: Scolytidae

Other Names: Ambrosia beetles, turpentine beetles, engraver beetles, shothole borer, timber beetles

Origin: Most bark beetles are native to North America, although many species also have been introduced over the years.

Biology: These are some of the most destructive insects in North America, to the health of living trees. They bore into the cambium tissues and feed in this thin area of living cells, killing trees quickly. They also may spread diseases to the tree, such as Dutch Elm Disease or Sudden Oak Decline. They do not infest milled lumber and will not survive in wood built into a structure, and their presence in a structure is due primarily to infested firewood being present inside. Various common names are given to the species to describe their activity or evidence of their presence. In general there is one generation per year, with all the feeding done by the larvae. The ambrosia beetles in this family leave feeding channels stained dark and devoid of fecal matter. Shothole borers leave many tiny little holes in the bark following adult emergence, and engraver beetles leave feather-shaped galleries just below the bark of the tree.

Identification: Bark beetles may easily be confused with small Bostrichid beetles – bamboo borer and lead cable borer – but easily are distinguished by their antennae. The antenna of a Scolytid bark beetle consists of a number of very small basal segments followed by a much larger, compact club made from 2 or 3 segments. Their head is usually visible when viewed from above, although the prothorax does enclose much of the head. They are without the rough ridges that are present on the top of the prothorax of the Bostrichid beetles. Evidence of bark beetle galleries is often seen in structural wood members, but always as evidence present prior to the milling of the lumber. This will usually be the evidence of the Ambrosia bark beetles as narrow channels or small holes with the interior black, and without any fecal matter present.

Characteristics Important in Control: Control is not needed for structural situations, as the beetles are not present in structural wood, and cannot infest it. If present in firewood the wood should be removed to the outside. Their presence in living trees will not be covered here.

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