Twig beetles are tiny (3 mm), dark brown insects that attack lateral shoots and twigs on pinyon and other pines. They mine out the cambium and pith on small twigs and branches and are often confused with Ips beetles. However, twig beetles are smaller, prefer thin bark and are found on smaller twigs and branches rather than larger branches or trunks. There is no boring dust at the base or a sunken appearance on the bark. The tree can be saved by pruning infested branches!
Twig beetles attack drought-stressed, recently-transplanted, weakened trees and are an early indicator for future tree problems. They are usually of secondary importance although a Pityopthorus twig beetle has been a problem in pinyon in combination with Ips.
Twig beetles can attack new growth that elongates after the first Ips spray (April) and before a second application (August). If twig beetles are attacking pines between applications, landowners can do the following: Reduce the number of trees sprayed to protect the most valuable ones;
Add a third spray in mid-May;
Alternate carbaryl and permethrin (Sevin® and Eight®) applications to avoid violation of directions on the labels.
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Updated Tuesday, October 13, 2015