Wood boring insects feed on the inner wood (xylem) of roots, trunks, branches or shoots of a plant. While there are hundreds of wood boring species that are not considered pests, some species can cause branch dieback or even mortality. Recently transplanted young plants and stressed plants are most susceptible to attack from wood boring insects. Damage occurs when the larvae of wood boring insects chew through the nutrient and water transporting tubes of the plant.

Serious internal damage is hidden inside tree trunks, roots, and branches.