“That is a bracing cold, an invigorating cold. Lord, is it cold!” – Sheldon Cooper
It is inevitable that when the temperatures drop below zero we are asked “Will this extended period of extremely low temps kill off ticks?”
First, the bad news. We do not expect the cold to directly affect blacklegged or dog ticks as they are adapted to this climate and will survive just fine under the blankets of leaf litter and snow.
The good news, followed by some bad news, is we are basically looking at a reversal of the large quantities of ticks in 2017 that began in 2015 when oaks in New York underwent a mast seeding event. (In simple terms, there was an enormous amount of acorns on the ground across the state. If you want to delve more deeply into the mast year phenomenon, check out Mechanisms of mast seeding: resources, weather, cues, and selection.) Abundant quantities of food led to a large quantity of small mammals in 2016. Large numbers of small mammals led to a substantial number of ticks in 2017. Researchers at the Cary Institute of Ecosystem Studies have decades of field research to back up the relationship, and lag time, between mast years and Lyme disease risk.
Which brings us to the current frigid weather, and probably even more importantly, the ice under the snow, and how it will impact small mammals. Animals that have a harder time finding food are more likely to (in order of lessening consequences) die of starvation, succumb to other stresses such as disease or predation, fail to mate, give birth to fewer young, and give birth less often. In a nutshell, there should be fewer hosts come spring. And fewer hosts eventually lead to fewer ticks. Good so far.
But there is some bad news, too. During the time of high tick numbers and fewer small mammal hosts, each of us, and our companion animals, are at greater risk of coming into contact with questing ticks. So as soon as the temperatures rise into the mid-30s (and we know you will be out enjoying the veritable heat wave), ticks will be questing and we need to Steer Clear of Ticks and the Diseases They Carry — the IPM Way.
I am afraid the search for a reason to fully embrace the cold continues.