Name: Pissodes strobi

Alias: White pine weevil. The adults are brown beetles white spots on their back. They have a long elephant trunklike nose and antennae protruding halfway down this nose. The larvae are hatched in cavities on the tree. They live under the bark and can be found by peeling the bark back of an area on a tree that is suspected for infestation. If the larvae are present, the bark will be easy to peel. As they move on from larvae to pupae, they bore into the tree. As they emerge, they leave perfectly round holes that look like the tree has been peppered with buckshot.

Crimes: Both the adults and the larvae feed on the terminal shoots, causing them to wilt and die in a signature “shepherd’s crook” appearance. They also feed on all new growth of pines, spruce and other conifers. Infected trees will appear sparse and their color will go from faded green to yellow or brown. Their exit holes can also be unsightly for wood used for asthetic purposes.

Redeeming Qualities: None known.

Sentence: Insecticides do exist to take care of white pine weevil, but they must be timed precisely when the adults are ovipositing — or laying eggs — in the spring. These insecticides are applied at the terminals of the tree. Chemicals can be avoided by removing infected branches, which also can reduce populations. It is best to prune back and destroy affected branches in the summer before the adults emerge, which is around mid-August to September.

For more information on dangerous and beneficial bugs, call UI Extension educator Joseph Sagers at 208-270-4031 or email

Load comments