The most damaging bark beetle species attacking Minnesota's pines are native engraver beetles (Ips species). Red (Norway) and jack pine are the most common victims of Ips pine engraver beetles, although white pine and spruce can also be infested. There are several other bark beetle species that inhabit pines, but they are rarely problematic. The management advice below applies to these other bark beetle species as well.
Ips pine engraver beetles can quickly kill a few upper-canopy branches and eventually the entire tree. Needles on attacked branches fade from green to yellow-green and then turn completely orange in a matter of weeks.
Fortunately, pine engraver beetles prefer to attack stressed pine trees or freshly-cut pine and spruce branches and trunks (called slash), so healthy trees are not usually harmed. Ips pine engravers cannot live in pines with loose bark or pines that have been dead for over a year.
It is not unusual to lose some mature pines in plantations from pine engraver beetles occasionally, so the loss of a few stressed trees should not cause concern. In some circumstances, if an area with many pines is damaged by wind, fire, or extreme drought, significant numbers of remaining pines can be attacked and killed by pine engraver beetles. Lightning strikes or thinning pines from late winter through summer without promptly removing slash can also promote pine engraver beetles attack of the remaining pines.
Ips pine engravers are found throughout Minnesota and are widely distributed in North America.