Reuters

 It’s killing some of the nastiest invasive insects around.

The hemlock woolly adelgid hails from Osaka, Japan. When it moved to the U.S. in the 1950s, it settled right in, facing no natural predators and feeding off the buffet of hemlock forests lining the eastern coast. Similarly, the gypsy moth, a European emigre, now gobbles up the leaves of millions of acres of trees each year. And the emerald ash borer, a beetle of Eurasian extraction, has killed millions of trees in North America in just over a decade, earning it the title of "worst forest problem in our lifetime" from a Colorado State University entomologist.

Together, these creatures now cause around $2.1 billion in economic losses in the U.S. each year. But they really don’t like the cold, it turns out. In fact, the one good thing about the unrelenting cold weather this winter is that it appears to be decimating the populations of destructive invasive insects that cost the US government and homeowners billions each year.

"This winter has been a godsend for the hemlock. Overnight temperatures dipped to minus 15 [Fahrenheit, or -26°C] here in Amherst [Massachusetts], and that’s cold enough to guarantee almost complete adelgid die-off," Joseph Elkington, a professor atthe  University of Massachusetts, Amherst, told the Worcester Telegram.

Elkington says that in some parts of North Carolina, subzero temperatures have killed 100 percent of the adelgids. In Massachusetts, around 80 percent of the population should die, according to a state official. Gypsy moths and emerald ash borers are similarly vulnerable to extreme cold; the U.S. Forest Service estimates that 80 percent of Minnesota’s emerald ash borers died in January. Other invasive insects, such as the southern pine beetle, which has been ravaging New Jersey, and the Asian stinkbug, may be dying off as well.

This undated file photo provided by the Minnesota Department of Natural Resources shows an adult emerald ash borer. The insect that could threaten one of South Dakota's most populous tree species moved even closer to the state in the past year. The emerald ash borer last year was found in Union County in southwestern Iowa, as well as in Boulder, Colo. South Dakota State University forestry expert John Ball said he thinks the Asian beetle will be found in South Dakota within five years. (AP Photo/Minnesota Department of Natural Resources
The emerald ash borer that’s eating America’s hemlocks. AP Photo/Minnesota Department of Natural Resources
 

Unfortunately, this is a kind of meteorological booby prize. The same extreme weather that may be causing polar vortexes is also making winters warmer on average—and that’s letting these insects live further and further north, making increasing swaths of the US hospitable to invasive species, which cause $143 billion in economic losses in the U.S. each year.

"Before this winter we had a couple of milder winters, likely representative of what will happen in the future, and the adelgid took off like gangbusters and killed a lot of hemlock in a matter of a couple of years," Elkington says. Those warmer winters will likely push the adelgid further north still, into Vermont, New Hampshire and Maine.
 

The cold may also kill off predator insects that forest officials have been releasing to take out invasive insects. For instance, parasitoid wasps that are supposed to control the emerald ash borer population in Michigan and other states are even more vulnerable to the cold than their prey, whose populations might recover more quickly as a result.

This post originally appeared on Quartz, an Atlantic partner site.

About the Author

Most Popular

  1. An aerial photo of downtown Miami.
    Life

    The Fastest-Growing U.S. Cities Aren’t What You Think

    Looking at the population and job growth of large cities proper, rather than their metro areas, uncovers some surprises.

  2. a photo of a BYD-built electric bus.
    Transportation

    A Car-Centric City Makes a Bid for a Better Bus System

    Indianapolis is set to unveil a potentially transformative all-electric bus rapid transit line, along with a host of major public transportation upgrades.

  3. Transportation

    When a Transit Agency Becomes a Suburban Developer

    The largest transit agency in the U.S. is building a mixed-use development next to a commuter rail station north of Manhattan.

  4. a photo of a tiny house in Oregon
    Design

    How Amazon Could Transform the Tiny House Movement

    Could the e-commerce giant help turn small-home living from a niche fad into a national housing solution?

  5. Warren Logan
    Transportation

    A City Planner Makes a Case for Rethinking Public Consultation

    Warren Logan, a Bay Area transportation planner, has new ideas about how to truly engage diverse communities in city planning. Hint: It starts with listening.

×