Insects and Disease

We provide technical assistance and training to private landowners and forest managers, designed to minimize insect and disease risk.

 

Our focus is on prevention and suppression of damaging insects, diseases, and weeds before and during outbreaks. We promote restoration of tree species most suited to the soils and environment in order to grow long-lived, productive and healthy forests.

(click the image to read the Idaho Response Plan for Invasive Insect & Disease Tree Pests)
Prevention is the best means to protect trees. Treatments focused on prevention result in reduction of tree mortality; thinning dense stands, applying preventative chemical barriers, pruning and favoring existing tree species most resistant to forest pests are good examples. Pest surveys and monitoring can prevent a pest from increasing to damaging levels and reduce tree mortality, when early detection is followed by a rapid response.

The IDL Forest Health staff cooperate with other state and federal agencies to complete several annual pest detection and monitoring surveys.

• Aerial detection surveys locate, identify, and map insect damage agents and the impacted tree species across most forested lands in Idaho.
• Monitoring surveys for the native Douglas-fir tussock moth provides predictive data of the next cyclic outbreak and informs management decisions to control the pest.
• Pheromone trapping surveys for the European and Asian gypsy moths detect incipient populations. Early detection of non-native pests increases the probability that eradication efforts will be effective and prevent widespread, long-term damage and mortality to urban and rural forests.

Fact Sheets

• Spruce Beetle
• Red Turpentine Beetle
• Wood Borer
• Herbicide and Road Salt Damage in Trees
• Herbicide Damage from Silvicultural Treatments
• Armillaria Root Disease
• Root Disease
• Defoliating Insects
• Western Spruce Budworm
• Bark Beetles 
• Fir Engraver
• Western Pine Beetle
• Douglas-Fir Beetle
• Pine Engraver
• Mountain Pine Beetle
• Secondary bark Beetles in Douglas-Fir
• Topkill in Young Larch

Other Information

• 2022 Idaho Aerial Detection Survey Map
• 2021 Idaho Aerial Detection Survey Map
• 2019 Idaho aerial detection survey map
• Root diseases in the Inland Northwest
• Are your trees at risk? Bark beetle brochure
• Field guide to diseases and insect pests of northern & central Rocky Mountain conifers

Douglas-Fir Tussock Moth

• Douglas-fir Tussock Moth Fact Sheet 2022
• Douglas-fir Tussock Moth Fact Sheet 2021
• Douglas-fir Tussock Moth Fact Sheet 2020
• 2021 Douglas-fir Tussock Moth Report 
• 2020 Douglas-Fir Tussock Moth Report
• 2019 Douglas-Fir Tussock Moth Report
• 2018 North Idaho Douglas-fir tussock moth monitoring report
• Douglas-fir tussock moth management guide
• Douglas-fir tussock moth leaflet
• Forest Insect & Disease leaflet