Cold Snap Fails To Lower Tick, Beetle, and Nematode Numbers on Cape Cod

Cape Cod's brutal winter won't shrink populations of lone star ticks, southern pine beetles, and beech leaf nematodes, according to local entomologists. The sub-freezing temps weren't cold enough to wipe out the disease-causing species that migrated to the area from southern states.

Lone star ticks survive harsh winters by lying dormant and hitting pause on development, explained Cape Cod Cooperative Extension entomologist Escher Cattle. This species triggered an outbreak of Alpha-gal syndrome on Martha's Vineyard—a tick-borne disease that can cause an allergy to red meat.

"Lone star ticks are pretty hardy to the cold, at least way hardier than we are," said Escher Cattle, per Provincetown Independent. "They've been able to handle the same temperatures that deer ticks and dog ticks do."

Snow works like a blanket. It shields dormant ticks tucked into leaf litter and soil. Air temps below 5 degrees Fahrenheit for at least eight hours can kill them, but six inches of snow keeps the cold from penetrating. The pests also make antifreeze-like compounds in their bodies that drop the freezing point of their blood.

Southern pine beetles face different odds. These insects destroy whole stands of pitch pines in just a few years and have damaged forests on Long Island. They can withstand air temps of 4 to 5 degrees Fahrenheit but live in tubes of pitch high up in trees, where they don't get snow insulation.

"I'm cautiously optimistic about how the cold weather could be affecting the southern pine beetle infestations," Cattle said. "The populations in Mashpee and Falmouth may face significant mortality as a result."

Stephen M. Smith works as a plant ecologist with Cape Cod National Seashore. He said the cold snaps will set back the beetle population for now. The insects can multiply and bounce back from such events, he said. The seashore has had no active infestations that have resulted in tree mortality so far.

Beech leaf nematodes will also make it through winter. The microscopic worms cause leaves to deform, curl, and wither. They burrow into shoot buds that shield them from cold weather, Smith said.

Cattle said ticks can wake from dormancy when air temps climb above 35 degrees Fahrenheit. He suggests wearing permethrin-treated shoes and socks for walks in the woods or yardwork once temps rise. Full-body tick checks are needed after hiking or working outdoors.

"It might feel silly in the dead of winter," he said, "but when it comes to avoiding tick-borne disease, prevention is key."