A Technical Report from The Bartlett Tree Research Laboratories 381
All species of pines are attacked by insects known as borers. As a group, these insects are highly damaging because they feed under tree bark. Bark beetles also bore under the bark of pines, but do not tunnel into the wood. Both groups interrupt vascular tissue and damage phloem where feeding occurs. Pines that become stressed by drought or root damage are often rapidly killed by borers. Many pine borers carry fungi, which cause additional vascular plugging problems within the trees.