Beetles' resurgence threatens NM pinon trees

They're back — the same species of bark beetle that decimated New Mexico's pinon trees a decade ago. Local arborists say populations of the match head-sized insect, also known as the ips or the engraver beetle, began increasing alarmingly at the summer's end. "Fortunately, their populations didn't explode until right at the very end of this season," said Rich Atkinson of Southwest Trees and Landscape. "If they had gotten going in the beginning, we'd be in greater trouble. Now, at least, folks can have warning and do something about it before (the beetles) emerge in the spring." Atkinson, Coates and other local tree experts say irrigating or applying insecticide can deter the beetles from infesting drought-stressed pinons, but once they have infected a tree with the blue-stain fungus they carry, the tree usually dies. The fungus retards the flow of moisture under the bark from the roots to the upper regions of the trees. "The fungus basically shuts down all the flow and corrupts the transmission of fluids," Atkinson said. "Once the beetles are in, the tree is dead — end game. The only thing you can do for your trees is basically try to prevent their chewing into the tree. And the only way to do that is to hydrate it to the point where its sap flow will spit the insect right back out — that's the natural defense — or coat it with chemicals that are detestable to the insects and they go somewhere else." There are more than 200 types of bark beetles. They are always present, but their numbers increase sharply during extended droughts. Millions of acres of pines in the Rocky Mountains, especially in Colorado and Wyoming, have been destroyed by an infestation that was identified in 1996, according to the U.S. Forest Service. In 2002, bark beetles turned to New Mexico's pinon, the state tree. By 2003, some were predicting the state would lose 80 to 85 percent of its pinons. By 2004, large swaths of pinon forests — for example, along Interstate 25 between Santa Fe and Eldorado — were dead. By 2005, the infestation began to subside. Bark beetle populations were back to normal by 2006...more