Two invasive insect species of concern in NE could have significant mortality of this year's population, if we can get cold enough. Both the Emarald Ash Borer (EAB) and Hemlock Woolly Adelgid (HWA) populations are susceptible to anomalous cold events, especially as temps approach -20F. "...researchers from the U. S. Forest Service and Minnesota Department of Agriculture found that the supercooling temperature for the Minnesota EAB population was about -13°F. Based on these results, a model was created that predicts that about five percent of EAB larvae should die when temperatures reach 0°F, 34 percent at -10°F, 79 percent at -20°F, and an impressive 98 percent should die at -30°F. (Venette, R.C. & Abrahamson, M. (2010) Cold hardiness of emerald ash borer PDF , Agrilus planipennis: a new perspective.)
Studies on the HWA show similar results. Also their mortality is higher when the cold occurs after a period of relatively milder conditions, as the insects gradually adapt their supercooling ability in sustained cold periods, so this event holds promise for a (temporary) setback for these insects in 2023 in NE. I'm cheering for -20F here overnight Friday for that reason alone. Seems like an ideal setup to hamper those invasives for a season anyway, while not prolonging the severe conditions for people and wildlife. Bring it!