In The NoCo

The emerald ash borer is spreading across the Front Range. Here’s how to protect your trees

By In The NoCo,

Published July 8, 2025 at 5:40 AM MDT

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An adult Emerald Ash Borer adult sits on a piece of bark. — The emerald ash borer is a small green insect that has been spreading around the front range for a decade. However, you are unlikely to see them if you have an infected ash tree because they burrow beneath the bark.

A tiny, green insect that bores under the bark of ash trees is spreading in Colorado.

The emerald ash borer has been making its way around the Front Range for the last decade. It damages ash trees and often kills them. And this year it’s been spotted in Denver.

Ash trees make up about one in every six trees in the urban forests along the Front Range. So what can we do to protect ash trees and even fight back against this pest?

An Emerald Ash Borer larvae burrows through a slab of wood.

Karim Gharbi is a horticulture specialist with the Colorado State University Extension who’s been on our show before. Karim joined Erin O’Toole to talk about the emerald ash borer and give a more specific idea of what this so-called “green menace” looks like.

CSU Extension offers guidance on fall and winter watering to keep ash trees strong. If you’re looking for an arborist, Trees are Good offers suggestions.

For more info on Front Range pests, listen to In The NoCo conversations about Japanese beetles and miller moths.

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In The NoCo

KUNC's In The NoCo is a daily slice of stories, news, people and issues. It's a window to the communities along the Colorado Rocky Mountains. The show brings context and insight to the stories of the day, often elevating unheard voices in the process. And because life in Northern Colorado is a balance of work and play, we celebrate the lighter side of things here, too.

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Ariel Lavery

Ariel Lavery grew up in Louisville, Colorado and has returned to the Front Range after spending over 25 years moving around the country. She co-created the podcast Middle of Everywhere for WKMS, Murray State University’s NPR member station, and won Public Media Journalism awards in every season she produced for Middle of Everywhere. Her most recent series project is "The Burn Scar", published with The Modern West podcast. In it, she chronicles two years of her family’s financial and emotional struggle following the loss of her childhood home in the Marshall Fire.

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Erin O'Toole

As the host of KUNC’s new program and podcast In the NoCo, I work closely with our producers and reporters to bring context and diverse perspectives to the important issues of the day. Northern Colorado is such a diverse and growing region, brimming with history, culture, music, education, civic engagement, and amazing outdoor recreation. I love finding the stories and voices that reflect what makes NoCo such an extraordinary place to live.

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Brad Turner

Brad Turner is an executive producer in KUNC's newsroom. He manages the podcast team that makes In The NoCo, which also airs weekdays in Morning Edition and All Things Considered. His work as a podcaster and journalist has appeared on NPR's Weekend Edition, NPR Music, the PBS Newshour, Colorado Public Radio, MTV Online, the Denver Post, Boulder's Daily Camera, and the Longmont Times-Call.

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