The Silver Lining to Falling Mercury: Celebrating a Deep Freeze

JAN 13

Has everyone thawed out from last week's deep freeze? While for most of us the plummeting temperatures meant staying indoors or wearing an extra layer of clothes, some rejoiced at the dropping mercury. Who would those crazy people be, you might ask? Entomologists, foresters, and naturalists see a silver lining to the extreme cold, a cold which has the potential to thwart or even kill invasive insects attacking our treasured native plants and trees.

One insect threatened by the cold is the wooly adelgid, a pest that destroyed hundreds of thousands of Eastern hemlocks since arriving to the United States from Japan in the 1950s. The tiny, aphid-like insect pierces the base of needles and sucks out the tree's nutritional supply. But Mother Nature has a way of leveling the playing field: temperatures just a few degrees below freezing are lethal for the wooly adelgid.

Another insect that hits a speed bump due to the cold is the emerald ash borer. Cutting an S-shape tunnel under the bark of ash trees, the borer feeds on the ash's conductive tissues, restricting the tree's necessary supply of water and nutrients. Though they have strategies against being killed by the cold (such as emptying their stomach of anything that could freeze), the emerald ash borer will die when the weather gets cold enough. Temperatures of minus 20 to 30 degrees Fahrenheit can kill as much as half the population.

Other harmful insects threatened by extreme temperatures are the southern pine beetle, some varieties of ticks, and even bed bugs. Though this is encouraging, scientists know that our climate can't be counted on as the primary means of eradicating these harmful insects. As the weather warms up, insect populations can rebound. Weather is an important tool, but population management continues to be the name of the game for entomologists.

So the next time the forecast is frighteningly frigid, just remember the silver lining - Mother Nature is doing her part to protect our natives. So light a fire, bundle up, and look forward to the spring time when you can see more of your favorite native trees and plants thriving after a cold, but advantageous winter!