PHILADELPHIA (CBS) - This “winter that just won’t end” has been trying for us humans, but it’s been murder on a type of bug that’s devastating Pennsylvania’s state tree.
Pennsylvania’s ranges of eastern hemlock have been an open salad bar for an invasive species, the hemlock woolly adelgid.
“Hemlock stands have been totally decimated,” says Donald Eggen, chief entomologist of the state Forest Pest Management. Counter-attacks have involved insecticides and deploying a predatory beetle, but our freezin’ season’s helped out too.
“Maybe there’s something nice that can be said about the cold temperatures is that when it does get down to starting about minus-10, you start getting mortality starting around 90-percent,” he said.
This doesn’t end the wooly adelgid threat because each survivor can produce up to 120 young a year, but it buys time for other control measures to work.
He says the cold has not been as lethal on another troublesome species.
“Emerald ash borer comes from Northern China, Mongolia and Eastern Russia. It gets cold there.”