Piñon pines devasted by fungus

Piñon pines devasted by fungus, bugs

August 9, 2001

THE DEVASTATION wrought by a fungus and a type of beetle shows in these dying piñon-pine trees on the property of Bill Proud on County Road P.

By Janelle Holden
Journal Staff Writer

An epidemic number of piñon-pine trees are dying in Montezuma County this summer, killed by a seemingly unstoppable fungus and vulture-like beetles who feed on the tree.

"It’s almost like a wildfire," explained Kenny Smith, a Montezuma County extension agent. Smith said he first noticed the problem in 1996, but the trees have been dying at their fastest rate this year.

"We’ve had a lot of trees die up here suddenly. I think it may partly be the drought," said Marilyn Colyer, bio-technology supervisor at Mesa Verde National Park. Colyer estimated that 1 to 2 percent of the piñon pines at Mesa Verde are dying, and the mortality rate may rise to 5 percent by the end of the summer.

Kent Grant, a forester for the Colorado Forest Service office in Durango, said the deaths are linked to a black-stain root disease, and an Ips beetle outbreak.

"A lot of the problems with the piñon-juniper seem to be aggravated by drought," explained Grant. "This is kind of nature’s way of taking care of stands that become overly dense and past their prime in many cases, and also maybe this is a reaction to the drought and other conditions."

Black stain is a fungal root disease spread through the root systems of piñon pines. So far, the fungus cannot be killed by any known chemical, and other than quarantine, little can be done. The fungus causes grayish-black streaks on the normally white tissue of the piñon pine. Once the fungus or drought weakens the trees, piñons are ripe for an infestation of the Ips beetles, which can help finish it off. But both can act independently of each other, said Grant.

Trees beset by both the disease and beetles often display the same symptoms, so unless the bark and underbark is inspected, it’s hard to tell what is causing the trees to lose their color and eventually turn Halloween orange. Trees can die as quickly as within three weeks of discoloration.

Although it didn’t work at Mesa Verde, the spreading might be controlled by digging a trench around the fringe of the infected area and clear-cutting the diseased trees. Unfortunately, this heavy work is outside the purview of Montezuma County.

"There’s no money to do it, and on top of that there’s no preventive treatment," Smith said.

Whether the epidemic could leave only the "j" in what foresters commonly call "pj," or piñon-juniper forest, is not yet known.

"It’s hard to predict where it’s headed," explained Grant. "Some of these insect and disease problems tend to be cyclical."

For landowners looking for evidence of the beetle, the extension office advises looking for a yellow or red boring dust in bark crevices on the tree trunk. Masses of pitch or half-inch pitch tubes also may be found sporadically on the trunk.

Landowners should also be aware that the dead trees on their property could cause a significant fire hazard. "It’s advisable to get dead trees out and burn them in a safe fashion, probably in the winter when we have snow," explained Smith.

Most of the dead trees are dying in pockets around the county. Some of the worst areas can be seen from Highway 145 between Dolores and Cortez.

"It seems to find a line," said Bill Proud, who owns 35 acres off of County Road 32.1 that have been hit. Proud said "hundreds" of trees have died on his property since he and his wife, Gayle Prior, bought the property four years ago.

"I can cut down 20 to 30 trees, and then I can do a 360 and there’s 20 to 30 more left to cut," said Proud. "It’s just an ugly experience."

But Proud is somewhat resigned to the whole phenomenon. "It’s part of nature," he said, looking at a meadow behind his house that was formerly filled with living trees.

Ric Plese, a horticulturist at Cliffrose Gardens, said some of his clients noticed the beetles clicking inside of the trees when they walked by them, and have come in to the store to ask for an insecticide.

Plese said the most effective chemicals have been taken off the market or are no longer mixed to treat this particular beetle.

Sevin, for instance, an insecticide manufactured by GardenTech, no longer contains molasses, the ingredient Plese thinks is necessary to kill the beetles. He recommends applying systemic insecticides such as disulfoton or acephate to the tree.