Bark Beetle Infestation Could Spell Doom for Plants in Colorado

Bark beetles have evolved to feed on various types of trees, However, drought conditions have caused the population of these beetles to grow at faster levels.
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The spring is almost upon us, and as the colder climate begins to make way for warmer, more friendly skies, an agricultural expert is raising concerns over the possibility of a plant pest to start growing in alarming numbers.

Recently, Dan West, an entomologist with the Colorado State Forest Service, explained on its official website that the spruce beetle (a species of bark beetle indigenous to the United States) could make a comeback in the new season, and could even grow to become a statewide problem.

A Rough Summer for Colorado Plants

The bark beetles have evolved to feed on various types of trees, with many of them acting as a form of natural control to cull weaker trees over time. However, West explained in the post that drought conditions have caused the population of these beetles to grow at faster levels.

These beetles have affected about 2 million of the 24.5 million forest acres across Colorado in the past two decades, West explains. This level of devastation was made possible through a partnership with another pest, the Western Spruce Budworm.

While the spruce beetle feeds on a plant’s phloem layer (that transports sugars to its roots), the spruce budworm focuses more on the needles of spruce trees. Their action weakens the ability of trees to photosynthesize. But, when joined by the hampered sugar transportation system caused by the spruce beetle, West warned that trees are acutely vulnerable at this point.

Forested Acreage Affected by Spruce Beetle in Colorado, 1996-2018
Forested Acreage Affected by Spruce Beetle in Colorado, 1996-2018. Source

However, despite the bleakness of the situation, West pointed out that there are various natural controls and human-made processes that can identify these pests and contain their spread. For instance, he pointed out that temperature regimes and natural precipitation could help in a forest ecosystem.

He explained further, “The strategy for controlling spruce beetles is by adding resilience, making certain trees more vigorous during periods of drought.”

An Old Foe Resurfaces

The spruce beetle has been named the most damaging pest of the year in Colorado for the eighth consecutive year, and forest managers across the state have been paying more attention to it, actively searching for ways they can help manage its spread. Last year, the USDA Forest Service, Rocky Mountain Region, and Colorado State Forest Service conducted an aerial survey and survey map. The results were published last month, which revealed that spruce beetle affected 89,000 acres of high-elevation Engelmann spruce across Colorado.

Although the report showed that the number of acres affected by the beetle had reduced for the 5th year in a row, it still revealed that the pests have continued to expand their footprint by infiltrating previously inaccessible areas. In 2019, the pest affected up to 25,000 new forest acres. Its primary points include portions of the San Juan Mountains as well as forestlands in and around the Rocky Mountains. Parts of the Sawatch Range and West Elk Mountains also saw the presence of the pests.

Colorado isn’t the only state in the country that’s trying to fend off an imminent pest invasion. Over in Hawaii, the state Department of Agriculture has announced that the Avocado lace bug has spread massively across the state, adding that farmers need to buckle up and prepare for an imminent invasion.

The Department explained that the bug was first seen last December in Oahu, and soon after, several plants across shops and farmlands started to show infestation signs. The Department has now collaborated with the University of Hawaii College of Tropical Agriculture and Human Resources to issue a comprehensive guide for farmers to spot them.

Robin Watson

Robin owns his own Landscape Gardening company based in the UK and has over 10 years professional experience working outdoors, creating beautiful landscapes for his clients in the UK. He is also a keen garden-grower and maintains his own fruit and vegetable gardens. He also has a level 3 Certificate in Practical Horticulture from The Royal Horticultural Society and is currently working on his first book about gardening. Contact him at

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