Montrose - Daily Press

Jason Monroe

MONTROSE - Not even an abnormally cold winter is likely to stop the spread of the Ips beetle, a menace that is terrorizing pinyon forests across the Southwest.

"I'm looking into that (how cold it would need to be), but my gut feeling is that it would have to get really cold," said Colorado State University Tri-River Area Extension Office Entomologist Bob Hammon. "And I'm half joking Š that if it gets that cold, we'll have more problems than the beetle."

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The Ips beetle is a one-quarter inch long black beetle that burrows into the bark of the pinyon and kills the tree when its larvae feast on the cambium layer. The beetle spreads to trees that are stressed, as the drought has done to many trees in the Southwest, and may cause a more active fire season due to the number of acres of trees killed by the infestation. The Ips beetle is semi-immune to the cold because it goes into a resting state during the winter and its body produces sugars and other natural antifreezes that help keep it alive even when temperatures drop below freezing.

The subzero temperatures recorded in the over the past weeks, including the minus 11 spike recorded at the National Weather Service observation station at the Montrose Regional Airport on Jan. 5, and the lingering chill that continues to grip the area, is not likely to kill many of the pesky insects.

"A lot of the beetles will overwinter at the base of trees and use the snow as insulation. Š They are tough, and they are in protected spots - under the bark and under the snow. Some insects, it's going to have a major influence on," Hammon said, noting that insects such as spider mites, a pest in local sweet corn crops, could have their infestation delayed by 10 to 14 days if the cold weather persists. "You would need significant, long-term cold to put a dent in them."

Archuleta County, just east of Durango, has seen an 80 percent kill in the pinyon pine population due to an Ips beetle infestation. Dolores and Montezuma counties are seeing similar kills, with up to 90 percent of the pinyons in the area killed by the beetles. The area around Montrose has seen some Ips activity, mainly in a swath starting on the Uncompahgre Plateau and continuing to Paonia. The area around Log Hill has also seen a number of pinyons killed by the beetle.

Hammon, after consulting with U.S. Forest Service Entomologist Roy Mask, said "a long-term cold or a sudden drop (in temperature) Š over a matter of hours" would also be enough to help kill off the pests.

However, Hammon noted, a sudden swing in temperature severe enough to kill off the beetle could result in severe tree damage and actually kill the tree off due to freezing. The best measures to prevent infestation from the beetle are watering and thinning, Hammon said. "But if you don't survive the next few winters, thinning won't be a problem (because most of the trees will be dead)."

"The key to controlling them isn't the weather or thinning, it is to get moisture to the trees at the right time in the season so they can fight off the beetles themselves."

Contact Jason Monroe via e-mail

at jasonm@montrosepress.com.

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