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Insects and diseases can pose serious threats to a forest’s health. Our foresters monitor insect and disease activity and trends, and respond to emerging threats to our communities’ forests.

Common Insect & Disease Concerns

By properly identifying the tree’s species and examining the specific symptoms of damage, you can make a reasonable diagnosis of the problem and select the proper treatment using this guide to Diagnosing Tree Disorders.

If your questions cannot be resolved with the information provided, please email the Montrose Field Office or call us at (970) 249-9051. Our foresters are available for consultation regarding insect and disease concerns.

Forest Insect & Disease Aerial Survey

The annual survey is led, coordinated and funded by the U.S. Forest Service. A small fixed-wing aircraft is flown between 1,000 to 1,500 feet above the treetops while surveyors mark on a map the location, number and identity of trees affected by insects or diseases. The CSFS has assisted in the aerial survey since the 1970s and began playing a larger role in 1997.

For more information, visit our Common Forest Insects & Diseases page.

Statewide Publications

Local Insects & Diseases by Tree Species

Dwarf mistletoe in Ponderosa pine, Ouray County
Dwarf mistletoe in Ponderosa pine, Ouray County

Ponderosa Pine

Piñon Pine


Tiger moth caterpillar in Piñon pine, Montrose County
Tiger moth caterpillar in Piñon pine, Montrose County


White Fir

Douglas fir Beetle, Ouray County
Douglas-fir beetle, Ouray County


Subalpine Fir

Ornamental Tree Insects, Diseases and Disorders


Learn More About the Montrose Field Office

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Map powered by the Colorado Forest Atlas from the Colorado State Forest Service