USDA has released an updated version of its emerald ash borer (EAB) map (PDF). It shows the counties in which authorities have detected the destructive, invasive beetle that is responsible for the deaths of tens of millions of ash trees in the United States.

The pest was first detected in the United States in Michigan in 2002. In 2019, the beetle has been newly detected in multiple counties in Minnesota, Missouri, Tennessee, New Jersey and Vermont, and one county each in Iowa and Delaware. It’s been detected in every state east of the Mississippi River except for Florida and Mississippi. The furthest west it has been detected is in Boulder, Colorado, where it was found in 2013. The pest has not made it further west since then.

Where it exists as a non-native pest, the EAB has no natural enemies to keep it in check. Authorities have attempted to control it and slow its spread by introducing tiny, parasitic wasps as biological control agents. These are not only attacking and killing the pests, but reproducing on their own.

The USDA Animal and Plant Health Inspection Service has proposed to remove EAB quarantines on the grounds that the extensive regulatory activities required to enforce them are no longer useful. Critics of this move say it’s premature. The comment period on this proposal has closed, but a final decision hasn’t been announced.

The USDA’s EAB Story Map gives a good primer on the pest, its spread across the United States, and the ongoing efforts to control it.