The emerald ash borer kills ash trees in America’s forests and backyards. 

(Photo: USDA by CC 2.0)

Colorado and other states across the country would benefit from tougher strategies aimed at preventing the spread of forests pests like the emerald ash borer, a new study says.

It estimates that the cost of addressing the impact of invasive insects is more than $2 billion a year nationally. Gary Lovett, the paper’s lead author says a lot of pests come in on shipping containers.

“They might come in on a port and can be shipped to Denver or somewhere else," Lovett said. "Anywhere that’s receiving large amounts of goods internally should be a focus of that kind of surveillance and eradication effort."

Lovett says many states have surveillance programs for forests pests—but those near where imported goods enter the United States should be beefed up.

The emerald ash borer was detected in Boulder in 2013. Since the pest entered the country, it’s killed millions of ash trees across the Midwest.