Some Good News About Winter: It's Killing Invasive Insects

The cold weather that has entrenched parts of the U.S. this winter is proving to be quite the pesticide.

This winter’s deep freeze is putting a number of invasive insects on ice in many states, theWashington Post reports.

The U.S. Forest Service says up to 80 percent of all emerald ash borers in St. Paul, Minn. died when January temperatures fell to -20°. The frigid temperatures are also making a difference in Wisconsin, where the ash borer population is plummeting.

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Ash borers – "the worst forest problem in our lifetime," according to a Colorado State University entomologist – prey on ash trees, which provide wood used for items ranging from baseball bats to church pews. They cause $2.1 billion in economic losses each year in the U.S., Quartz reports.

But it turns out these pesky bugs don't like the cold.

Mary Holleback of the Riveredge Nature Center in Saukville, Wis. tells WISN that scientists believe the cold weather is killing borer larvae.

“If it gets to be 20 below zero for a sustained amount of time, you kill off about 80 percent of them,” she said.

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Other invasive insects – the hemlock woolly adelgid in Massachusetts, southern pine beetle in New Jersey, gypsy moths and the Asian stinkbug – may be affected as well.

While this sounds like good news, the cold doesn't mean the end of bugs, which made their way to the U.S. from all over the world and thrived in relatively warm winters.

University of Maryland entomology professor Mike Raupp said what we’re seeing is more like a reprieve than a victory over the invasive insects.

Raupp added it may take 10 years to study whether cold weather can kill off a significant number of pests.