It’s been a few years since we’ve had a truly cold, snowy winter. While most of us aren’t fans of temperature extremes, cold weather often sparks discussions of weather-related folk wisdom. One topic that’s coming up repeatedly is whether sub-freezing temperatures help reduce insect populations. Curious to see if there’s truth to this belief, I decided to do some research.
Extreme cold can reduce insect populations by killing overwintering insects, particularly those that emerge early. However, the severity of the impact depends on several factors, including the insect species, the duration of the cold snap, and how low temperatures drop. Sudden deep freezes can be especially harmful to insects that have already become active. Additionally, extreme cold can disrupt insect life cycles, delaying reproduction and affecting overall population numbers.
Insects are remarkably resilient and have evolved fascinating ways to survive harsh winters. While I’d love to believe that our recent cold temperatures will significantly reduce non-beneficial insect populations this spring, it’s not a guaranteed outcome. Freezing temperatures pose a threat, but many insects have developed strategies to endure the cold.
To understand how, let’s go back to science class. Insects are ectothermic, meaning they cannot generate their own body heat like mammals. Some, like honeybees and ants, survive winter by relying on their colonies. Ants, for example, spend the growing season gathering food, then seal off their nests once cold weather hits. Inside, they cluster together to conserve body heat and protect their queen.
Other insects enter a state similar to hibernation, called diapause, where they become almost completely metabolically inactive. During diapause, they don’t eat, drink, grow, or move, allowing them to conserve energy until conditions improve. This state can be triggered by cold temperatures, food scarcity, or changes in daylight hours.
Some insects take winter survival a step further by producing a natural antifreeze. Here’s another quick science refresher: When water freezes, it expands, and ice crystals can rupture cells. Certain insects can lower the freezing point of water inside their bodies, preventing ice formation and protecting themselves from cold damage.
While many insects are well-equipped to survive winter, there are still steps you can take to help control populations of unwanted pests. One effective method is scraping off egg masses from trees. Our region has seen a surge in spotted lanternflies, and destroying their eggs before they hatch can help prevent another outbreak. Another strategy is applying horticultural oils, such as neem oil or Bonide All-Seasons Horticultural Spray, to kill overwintering insects and smother their eggs. Just be sure to apply these treatments before leaves emerge in the spring.
However, pest control shouldn’t come at the expense of beneficial insects. One of the best ways to protect them is by doing nothing! Delaying garden cleanup provides vital winter shelter for helpful insects that rely on leaf litter, plant stems, and fallen bark. By waiting to tidy up, you support an entire ecosystem of beneficial insects that play a crucial role in your garden’s health.
As we get closer to spring, remember that if you have any questions related to gardening, lawn care, or pest control, we’re here to help! We don’t mind your questions. We don’t mind them at all!
