Subzero cold snap bad for moth eggs but wasn't long enough to get rid of pine beetles

The cold this week may have been sufficient to kill moth eggs larvae in blankets but still lacked the oomph needed to terminate mountain pine beetles burrowed into Rocky Mountain forests."We need it to be sustained, at least two or three weeks" with temperatures of minus 20 or lower, said U.S. Forest Service spokeswoman Janelle Smith. "These short cold snaps will not do the job." That's because beetles' bodies produce insulation material that serves as an anti-freeze around them under tree bark. Beetles since 1996 have infested 4.6 million acres of forests in Colorado and Wyoming. Subzero temperatures in Denver, however, may have plunged low enough to zap moth eggs that lead to springtime unraveling of blankets, sweaters and fine rugs.