Insects & Diseases

Forest Health Protection surveys our forests to detect insect and disease outbreaks, provides assistance to land managers to manage pests and develops tools for detection and management.

Native forests and diseases are important components of forest ecosystems in Oregon and Washington. By affecting the growth and mortality of individual trees, they influence the species composition, stand structure, and ecological succession of forest stands. They also have many other important ecological roles, such as recycling nutrients, pollinating plants, and providing food for wildlife. Healthy forest ecosystems in the Pacific Northwest include thousands of species of forest insects and pathogens. They also occasionally can kill trees and impact forest health. Several native species of insects and diseases, such as mountain pine beetle and heterobasidion root disease, have had considerable impacts on forests in the Pacific Northwest.

Introductions of non-native invasive insects and diseases, such as the balsam woolly adelgid, Port-Orford-Cedar root disease and white pine blister rust, have had a significant and lasting detrimental impact on the ecology of the Pacific Northwest. The Forest Service and state partners work closely with APHIS to detect and manage these invasive pests.

Forest Health Publications and Reports

Annual Forest Health Highlights reports are available for Oregon and Washington from 1998 to the present, as well as Forest Insect and Disease Conditions reports that date back to 1933, 1-page Forest Disease Management Notes for 50+ forest tree diseases, and many other publications and reports about western forest insects and diseases.

View a catalog of online publications and links about western forest insects and diseases.

Currently featured: Douglas-fir Tussock Moth, a native defoliator

The Forest Insect and Disease Leaflet (FIDL) series includes a broad range of forest insects and pathogens that are found across North America with both conifer and broad-leaf hosts. Each leaflet describes its subject's distribution, appearance, life cycle, symptoms and management.

Western Forest Insects & Dise