Last Updated on February 16, 2021
After two weeks of sub-zero temperatures in the Twin Cities, is there a silver lining with Emerald Ash Borer (EAB) being eliminated? Sadly, no.
While the extreme cold likely killed off some EAB, not enough insects were killed to justify ending protective treatments.
How Does EAB Survive the Winter?
February of 2021 saw record-breaking low temperatures in the Twin Cities and across the state. It may be hard to believe insect larvae could survive those conditions, but thanks to special physical adaptations many do. As the Minnesota Department of Natural Resources explains, some insect larvae also spend the winter insulated by tree bark, or by burrowing below the snow line, which further increases their chance of survival.
Is There Any Good News?
Minnesota winters and polar vortex events could be seen as a helpful bonus in EAB management. However, easing up on preventative treatments in the hope that extreme weather will take care of EAB would be a mistake. According to the MN DNR, “While frigid winter temperatures may be an added benefit for now, we should not allow the cold to give us a false sense of security when it comes to actively managing Minnesota’s ash resource.”
On the bright side, extreme cold may give Minnesota a slight advantage in preserving ash trees. Continued treatment will be even more effective in dealing with an EAB population that has been weakened or reduced. On the other hand, as an invasive species, EAB enjoys many advantages, such as a lack of natural predators. If left unchecked, its population can bounce back leaving high-value ash trees just as vulnerable as they were before.
What Can You Do?
- Avoid spreading EAB—never transport ash logs, lumber, brush, or wood chips from a quarantined into a non-quarantined area.
- Consult a licensed arborist—see if your ash tree is a good candidate for treatment, or removal and replanting with another species.
- Contact your City Forester—ask if they have an EAB management plan, or click here to see if you live in one of Rainbow Treecare’s Partner Cities.