The tiny insect can turn entire pine forests into bleak landscapes.
Mountain pine beetles, which have devastated lodgepole pine forests in western North America, have been found in a new type of tree, the jack pine.
Jack pines cross the entire continent, which could ultimately wipe out pines on the U.S. East Coast.
Cold temperatures currently keep the spread at bay, but they may not last as the climate warms.
The mountain pine beetle is one step closer to crossing North America and turning eastern pine forests into the same bleak landscapes that have scarred the Mountain West in recent years.
Some scientists say it is inevitable that the tree-killing insect will spread all the way east via a corridor of jack pines across northern Canada's boreal forest. The question is: When? Others are more skeptical.
Either way, researchers have now shown that the beetle has invaded a new species of pine on the eastern side of the Rocky Mountains in Alberta, Canada, with potentially serious consequences.
In a report published this week in Molecular Ecology, researchers analyzed DNA from trees at the frontier of the beetle invasion in Alberta to demonstrate that the beetle is now infesting jack pines in addition to lodgepole pines, its typical target.