Forest Service

U.S. DEPARTMENT OF AGRICULTURE

FS–1219 | November 2023

Major Forest Insect and

Disease Conditions

in the United States: 2022
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Major Forest Insect and Disease Conditions

in the United States: 2022

Acknowledgments

The annual forest conditions report provides information generated through the combined efforts 

of U.S. Department of Agriculture (USDA), Forest Service employees; State agencies; and other 

partners. Their dedication to the monitoring, detection, suppression, treatment, and management 

of our forested lands for insects and disease makes this report possible.

Report compiled by S. Sky Stephens, Sheryl A. Romero, and Frank J. Krist (USDA Forest Service, 

Forest Health Protection).

Photo credit

Cover photo: Fall foliage from Foote Pond Overlook in the Huron-Manistee National Forests. 

Photo by Brendon O’Dell, USDA Forest Service.

Copies of this report are available from:

U.S. Department of Agriculture, Forest Service

Attn: Forest Health Protection

1400 Independence Avenue, SW

Stop Code 1110

Washington, DC 20250–1110

Email: stephanie.s.stephens@usda.gov

This report and other Forest Health Protection materials can be found online at:

https://www.fs.usda.gov/foresthealth
Forest Health Protection Offices/Regions

Preface

This report on the major insect and disease 

conditions of the Nation’s forests represents 

the 72nd annual report prepared by the U.S. 

Department of Agriculture, Forest Service. The 

report focuses on major insects and diseases 

that annually impact our Nation’s forests. This 

2022 update provides a national summary of 

the major changes and status of major forest 

pests with updated charts, tables, and maps. 

Additional information on these and other 

pests is available at: https://www.fs.usda.gov/

foresthealth/. 

The information in this report is provided by the 

Forest Health Protection program of the Forest 

Service and its State partners. This program 

serves all Federal lands, including National Forest 

System lands and lands administered by the 

U.S. Departments of Defense and the Interior, as 

well as Tribal lands. The program also provides 

assistance to private landowners through State 

foresters and other State agencies. Key elements 

of the program are administered by Forest 

Service and State program specialists to detect 

and report insect and disease epidemics through 

annual detection and monitoring surveys.

For additional information about forest health 

conditions, contact a Forest Service office (see 

map for office coverage) or your State forester.

USDA Forest Service

Washington Office

Stop Code 1110

1400 Independence Avenue, SW

Washington, DC 20250–1110

703–605–5344

USDA Forest Service

Northern Region (R1)

Federal Building

200 East Broadway

P.O. Box 7669

Missoula, MT 59807–7669

406–329–3308

USDA Forest Service

Rocky Mountain Region (R2)

1617 Cole Boulevard, Building 17

Lakewood, CO 80401

303–275–5350

USDA Forest Service

Southern Region (R8)

1720 Peachtree Road, NW

Atlanta, GA 30309

404–347–3540

USDA Forest Service

Eastern Region (R9)

626 East Wisconsin Avenue

Milwaukee, WI 53202

414–297–3600

USDA Forest Service

Alaska Region (R10)

3301 C Street, Suite 202

Anchorage, AK 99503–3956

907–743–9455

USDA Forest Service

International Institute of 

Tropical Forestry

Jardín Botánico Sur, 

1201 Calle Ceiba

San Juan, PR 00926

787–766–5335

USDA Forest Service

Southwestern Region (R3)

333 Broadway Boulevard, SE

Albuquerque, NM 87102

505–842–3247

USDA Forest Service

Intermountain Region (R4)

324 25th Street

Ogden, UT 84401

801–625–5759

USDA Forest Service

Pacific Southwest Region (R5)

1323 Club Drive

Vallejo, CA 94592

707–562–8921

USDA Forest Service

Pacific Northwest Region (R6)

1220 SW 3rd Ave.

Portland, OR 97204–3440

503–808–2913

CONTENTS

Forest Health Protection Offices/Regions ii

Preface iii

Introduction 1

2022 Highlights of Tree Mortality and Damage

from Insects and Diseases 2

Cogongrass 5

Rapid ‘Ōhi‘a Death 6

Beech Leaf Disease 7

Southern Pine Beetle 9

Emerald Ash Borer 11

Fir Engraver 13

Spongy Moth 15

White Pine Blister Rust 17

Hemlock Woolly Adelgid 19

Oak Wilt 21

Roundheaded Pine Beetle 23

Spruce Beetle 25

Sudden Oak Death 27

IMPORTANT: When interpreting maps throughout this document, note that data are displayed at the county scale 

only. For example, if damage was reported at just one location in the county, the entire county is displayed as affected. 

This standard convention is used because data for most pests are collected only at the county level. If the damage 

was reported at finer scales, many areas would not be visible at the scale used in this publication. The maps represent 

only what is reported as mortality or defoliation and not the total infestation of a particular pest. In any given year, 

some areas are not surveyed due to physical limitations, such as forest fires, weather events, or limited resources. Data 

collected from ground and aerial surveys used in this report represent a single snapshot in time for a given year. More 

frequent surveys are conducted in specific areas on a case-by-case basis. By combining these surveys over time, this 

report captures general trends and conditions of selected insects and diseases across multiple years.

ii MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 iii
Introduction

Insects and diseases play critical roles in maintaining 

healthy, resilient ecosystems. They also can be among 

the most serious economic and environmental threats 

to the forests and urban landscapes in the United 

States. Trees respond to environmental cues and may 

be positively or negatively impacted by these changes, 

altering ecosystem services derived from forested 

lands, including timber, recreation, tourism, clean 

water, energy, wildlife habitat, and jobs. To understand 

how conditions are changing and to protect species, 

forests are surveyed for insect and disease extent 

and intensity on an annual basis. Federal and State 

agencies and other stakeholders work together to use 

this information for management to ensure resilient 

forests are sustainable into the future. The overall tree 

mortality caused by insects and diseases varies by 

year and by pest, and cumulative effects can cause 

significant change.

TREE MORTALITY

In 2022, more than 8.4 million acres with tree mortality 

caused by insects and diseases was observed in the 

United States. A total of 462 million acres of forests 

were surveyed in 2022. The total tree mortality 

reported in 2021 was 5.8 million acres with 423 million 

acres of forests surveyed. Total tree mortality is difficult 

to compare year to year based on survey coverage. In 

some areas, specific queries can be made to identify 

localized change where surveys were completed in 

both years. 

In addition to mortality, defoliating pests can damage 

trees by eating leaves or needles, causing significant 

losses of foliage and altering forest health. A single 

defoliation event does not usually cause tree mortality; 

taken together with repeated attacks or severe abiotic 

factors, such as weather and drought, trees can 

succumb to these defoliating insects or be predisposed 

to other insects and disease impacts. In 2022, surveys 

identified 5.9 million acres of defoliation and other 

types of damage.

Every year, hundreds of native and nonnative insects 

and diseases damage our Nation’s forests. This report 

provides descriptions of major insects and diseases 

that contribute to annual tree mortality and damage. 

Additionally, the “Feature” section describes pests 

that the Forest Service and its partners are closely 

monitoring. While each pest is reported separately, 

multiple pests may be active in the same area causing 

mortality to multiple host trees, magnifying the 

change in forest condition and creating complex forest 

management challenges. 

For more information on all the mortality and damage 

agents, please visit:

https://www.fs.usda.gov/foresthealth/

462 million acres surveyed

SOUTHERN PINE BEETLE

SOUTHERN PINES

Additional trap detections in Maine after 

initial 2021 detection 

Over 9,000 acres with mortality reported

in New York

RAPID ‘ŌHI‘A DEATH

‘ŌHI‘A

Tree mortality continues to spread on 

Hawai’i Island

Tree wounding by invasive ungulates 

increases ROD infections in HI

BEECH LEAF DISEASE 

BEECH

Michigan confirms first occurrence

Foliar symptoms observed in forests and 

landscape trees in the Northeast

TREE MORTALITY SURVEY TRENDS 2013–2022

WHITE PINE BLISTER RUST

FIVE-NEEDLE PINES

Whitebark pine was designated as 

threatened under the Endangered 

Species Act

Whitebark pine mortality is extensive 

in high-elevation forests in the Western 

United States

FIR ENGRAVER

WESTERN FIRS

Mortality attributed to fir engraver on 

nearly 3.4 million acres

Drought conditions continue to promote 

fir engraver activity in the West

8.4

MILLION ACRES

WITH DEAD TREES

5.9

MILLION ACRES

WITH

TREE DAMAGE

EMERALD ASH BORER

ASH

First new State detection since 2018 occurred 

in Oregon 

Ash mortality continues in impacted States

SPONGY MOTH

HARDWOODS

Reduced defoliation reported across 

States heavily impacted in 2021

1.7 million acres with defoliation 

reported predominately in MI and PA

ALL TREE MORTALITY

8.4 MILLION ACRES

IN 2022

ACTIVITIES SUPPORTED BY FOREST HEALTH PROTECTION

BEECH LEAF 

DISEASE

SOUTHERN PINE 

BEETLE EMERALD ASH BORER RAPID ‘ŌHI‘A DEATH FIR ENGRAVER SPONGY MOTH WHITE PINE BLISTER RUST

Ongoing survey 

detection

Treatment of 

active infestations 

and thinning 

forests for 

prevention

Providing treatments, 

technical assistance, 

community response 

planning, and 

outreach

Detection survey, 

rapid response, 

sanitation, 

and resistance 

screening

Surveying, 

suppression, 

and developing 

management 

options

Eradication, 

suppression, and 

Slow the Spread 

Program

Surveying, 

resistance 

screening, and 

planting

2022 HIGHLIGHTS OF TREE MORTALITY AND DAMAGE 

FROM INSECTS AND DISEASES

FOREST HEALTH PROTECTION

SPONGY MOTH

1.7 M DEFOLIATION ACRES

IN 2022

FIR ENGRAVER

3.4 MILLION ACRES

IN 2022

 RAPID ‘ŌHI‘A DEATH

93,000 ACRES

IN 2022

462

MILLION ACRES

surveyed in 2022

8.4

MILLION ACRES

with dead trees in 2022

5.9

MILLION ACRES

with tree damage in 2022

1 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 2
Beech leaf disease Southern pine beetle Emerald ash borer Rapid ‘ōhi‘a death Fir engraver Spongy moth White pine blister rust * Other damage

*Includes damage from spruce budworm, western spruce budworm, western blackheaded budworm, spruce beetle and other 

western bark beetles, eastern larch beetle, browntaill moth, forest tent caterpillar, and many other less significant pests.

2022 INSECT AND DISEASE SURVEY—WATERSHEDS WITH TREE DAMAGE

3 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 4
Invasive plants are a major threat to our Nation’s 

forests and grasslands. Millions of acres across the 

United States are impacted by these invasive species, 

threatening the ecological integrity and biological 

diversity of our forests and causing significant negative 

economic impacts. The establishment and spread 

of invasive plants can displace native species and 

negatively impact soils, water, wildlife, recreation, 

forest productivity, and fire regimes. 

Cogongrass is one of the world’s worst invasive 

plants. First introduced in the early 1900s in Mobile, 

AL, cogongrass continues to spread. Cogongrass is 

native to southeast Asia and has become established 

throughout the Southeast in Texas, Louisiana, 

Mississippi, Alabama, Georgia, Florida, South Carolina, 

North Carolina, and Tennessee. Cogongrass suppresses 

other plants’ growth, displaces native plants and 

animals, and can alter fire regimes causing more 

frequent and intense fires. Cogongrass thrives in 

disturbed areas, including pastures, fields, forests, and 

transportation and utility rights-of-way. 

Mississippi, Alabama, and Florida are significantly 

impacted by cogongrass with over 1 million acres 

infested. In 2022, Georgia identified 152 new 

detections of cogongrass, bringing the total known 

infested area to nearly 500 acres across 73 counties. 

Additional reports of infestations were also made in 

South Carolina and North Carolina. 

Acreages with extensive cogongrass infestations 

are economically and ecologically degraded. Where 

cogongrass is widespread, eradication efforts are 

continuous, arduous, and expensive. Preventing, 

detecting, monitoring, and managing invasive 

species and restoring ecosystems impacted by these 

organisms is an immense and continuous task that 

requires collective efforts from local, State, and Federal 

agencies in addition to community support.

Cogongrass forest infestation. Photo by Chris Evans, University of Illinois, 

Bugwood.org.

FEATURE EXOTIC

Cogongrass impacts fire 

regimes in the South.

Cogongrass

Imperata cylindrica

Tree mortality spreads on 

Hawai’i Island.

Rapid ‘Ōhi‘a Death

Ceratocystis lukuohia and Ceratocystis huliohia

‘Ohi‘a (Metrosideros polymorpha) is the most common 

tree species in Hawaii’s native forests; it accounts for 

50 percent of all forest trees in the State. Growing from 

sea-level to nearly 8,000 feet in elevation, ‘ohi’a’ occurs 

in dry, mesic, and wet forests. ‘Ohi‘a-dominated forests 

cover 865,000 acres statewide, with 618,000 acres 

occurring on Hawai‘i Island.

In 2022, rapid ‘ohi‘a death (ROD) continued to spread 

on Hawai‘i Island, mostly filling in areas where only 

scattered mortality occurred. Surveys have determined 

that areas with invasive hoofed animals are 

experiencing higher incidence of ROD. On Kauai, both 

Ceratocystis species have been detected in multiple 

areas and managers on that island are responding 

with ROD containment strategies. Only C. huliohia

has been detected on Oahu, while a single detection 

of C. huliohia on Maui was destroyed and no further 

detections have been made on the islands making up 

Maui Nui. Limited ROD detections on Oahu and Maui 

indicate that ROD response strategies are making a 

difference in protecting high-value forests.

Cogongrass wildfire. Photo by Charles T. Bryson, USDA Agricultural Research 

Service, Bugwood.org.

INVASIVE PLANT RANGE

Typical staining caused by Ceratocystis sp. A in ‘ōhi‘a. 

Photo by J. B. Friday, University of Hawai`i.

ÌTree mortality continues to 

spread on Hawai’i Island

ÌTree wounding by invasive 

ungulates increases ROD 

infections in Hawaii

FOREST DAMAGE AND RANGE* HOST: ‘ŌHI‘A

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

*Annual insect and disease surveys are conducted by Forest Health Protection to detect 

forest pest damage and/or mortality when there are concerns about forest pest activity that 

can cause significant economic and environmental harm.

Damage Detections as of 10/31/2022

Defoliated ‘ōhi‘a tree infected with Ceratocystis huliohia. Photo by J. B. Friday, 

University of Hawai`i.

Nonnative Range in 2022

5 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 6
Banding and discoloration caused by several years of beech leaf disease 

infection. Photo by Matt Borden, Bartlett Tree Experts.

Dark interveinal bands indicating beech leaf disease infection. Photo by Matt Borden, Bartlett Tree Experts, Bugwood.org.

Bands at various severity levels indicating beech leaf disease infection. 

Photo by Matt Borden, Bartlett Tree Experts, Bugwood.org.

Cupped, shriveled, and misshapen leaves associated with beech leaf disease 

infection. Photo by Matt Borden, Bartlett Tree Experts, Bugwood.org.

Banding and discoloration caused by several years of beech leaf disease 

infection. Photo by Matt Borden, Bartlett Tree Experts, Bugwood.org.

EXOTIC

First detection in 

Michigan.

Beech Leaf Disease

Litylenchus crenatae mccannii

Beech leaf disease (BLD) continued to spread in the 

New England and mid-Atlantic States of Connecticut, 

Maine, Michigan, Massachusetts, Ohio, New Hampshire, 

New York, New Jersey, Pennsylvania, and Rhode Island. 

Damage has been observed in both 

forest and landscape settings. The 

disease has also been confirmed to 

occur in nurseries.

Beech leaf disease has been documented since 

2012 in areas of northern Ohio. In Connecticut and 

Massachusetts, BLD is confirmed in all counties. In 

Pennsylvania, 65 out of 67 counties had BLD positives 

in 2022. In New Jersey, two new counties reported 

the disease in 2022. The heaviest impacts of BLD 

occurred in the northeastern corner of the State. Beech 

leaf disease was first detected in St. Clair County, MI 

on private land in 2022 then subsequently in both 

Oakland and Wayne Counties. In Virginia, the disease 

has been identified in Fairfax County. Submitted 

samples to USDA’s Animal and Plant Health Inspection 

Service (APHIS) confirmed Litylenchus crenatae 

mccannii, the nematode responsible for BLD. 

HOST: BEECH

ÌMichigan confirms first occurrence

ÌFoliar symptoms observed in 

forests and landscape trees in the 

Northeast

FOREST PEST DETECTIONS* County Detections as of 10/31/2022

First Detected in 2022

First Detected in 2021

First Detected in 2020

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

*Forest pest detections are recorded at the county level when pest presence is determined and may not be reflective of damage severity.

7 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 8
FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

Pitch Pine Range

Affected State

Pest Not Yet Detected

Forest Service Region

Aerial view of southern pine beetle infestation. Photo by Andrew J. Boone, 

South Carolina Forestry Commission, Bugwood.org.

Loblolly pine mortality caused by the southern pine beetle. Photo by Erich G. Vallery, USDA Forest Service, Bugwood.org. Adult southern pine beetle on a pitch tube is evidence of an attack on the 

host. Photo by Erich G. Vallery, USDA Forest Service, Bugwood.org.

Blue staining in a cut log is a symptom of southern pine beetle damage. 

Photo by Erich G. Vallery, USDA Forest Service, Bugwood.org.

NATIVE

Monitoring traps 

detect additional 

southern pine 

beetles in Maine.

Southern Pine Beetle

Dendroctonus frontalis

In 2022, southern pine beetle (SPB) activity was 

observed on less than 14,000 acres. The SPB caused 

light mortality across Mississippi, Alabama, Georgia, 

South Carolina, and Florida with outbreak levels 

recorded on national forests in Mississippi and South 

Carolina. 

Scattered infestations of the SPB occurred across 

the Southern States, including Mississippi and 

South Carolina and to a much lesser extent in 

Georgia, Alabama, North Carolina, and Virginia, on 

approximately 3,400 acres. Southern pine beetle 

activity was reported in “spots”—areas of beetle 

activity typically less than 1 acre—in Alabama, Florida, 

Georgia, Mississippi, North Carolina, and Virginia. The 

Homochitto National Forest and Bienville National 

Forest in Mississippi and the Francis Marion National 

Forest in South Carolina saw the heaviest tree mortality 

caused by the SPB. 

In the New England and the mid-Atlantic States of 

Maryland, Pennsylvania, Delaware, Rhode Island, and 

New Hampshire, the only detections of SPB remained 

in traps, with a few exceptions. In Massachusetts, 

infested trees, two pitch pines, were detected for 

the first time. The SPB was reported in traps in 

Pennsylvania, New Hampshire, Rhode Island, and 

Maine. Pennsylvania State cooperators detected the 

SPB in a new county—Cumberland County—in 2022. 

Tree mortality or infestation was reported in New 

Jersey and New York. 

In the mid-Atlantic, tree mortality caused by the SPB 

was generally low. Tree mortality was only observed 

within limited portions of the New Jersey Pine Barrens.

HOST: SOUTHERN PINES

ÌAdditional trap detections in Maine 

after initial 2021 detection 

ÌOver 9,000 acres with mortality 

reported in New York 

9 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 10
Emerald ash borer adult. Photo by Dan West, Colorado State Forest Service.

Emerald ash borer galleries. Photo by David Cappaert, Bugwood.org.

EXOTIC

Oregon identified 

emerald ash borer 

in June 2022.

Emerald Ash Borer

Agrilus planipennis

The emerald ash borer (EAB) was detected in Oregon in 

2022. The Oregon find represents the first detection in 

the Pacific Northwest and the first new State since 2018. 

The EAB continued to spread to new counties within 

the 35 previously confirmed infested States with 

impact to urban and natural forests. Ongoing tree 

mortality and decline continues to have increased 

impacts on forests and their products and services. 

Throughout New England and the Eastern, midAtlantic, Central, and Southern States, tree decline 

and mortality caused by the EAB continued to impact 

urban and suburban communities and natural forest. 

Most States continued to identify additional impacted 

counties and communities. Mississippi, Florida, and 

Oklahoma remain uninfested. In the Great Plains and 

intermountain west the EAB continues to be active in 

Colorado, Kansas, Nebraska, and South Dakota. 

Surveying, trapping, biosurveillance, and monitoring 

and detection programs, combined with observations 

from citizens and green industry professionals, identify 

and quantify areas impacted by the EAB. Tree loss is a 

significant concern in newly impacted areas where ash 

resources are often concentrated in river corridors and 

in urban landscapes. 

OREGON IN FOCUS

On June 30, 2022, the emerald ash borer was detected 

in 16 small ornamental ash trees at an elementary 

school in Forest Grove, Washington County, OR. 

Additional infested trees were identified in nearby 

parks, street plantings, and private properties. Some 

of the infested trees were adjacent to native riparian 

forests and conservation plantings of Oregon ash, 

Fraxinus latifolia, an ash species native to the Western 

United States. Oregon ash occupies an important 

riparian niche providing shade, leaf and mast inputs, 

and bank stabilization to riparian habitats occupied by 

endangered fish and plants. 

The Oregon Emerald Ash Borer Readiness and 

Response Plan, prepared in 2018, was quickly 

implemented. The Oregon Department of Agriculture 

was declared the lead agency. An EAB Task Force, with 

approximately 40 members and subcommittees on 

communication, training, surveys and monitoring, 

integrated pest management, wood waste and wood 

utilization, research, and funding, was established and 

meets monthly. 

The public was encouraged to report suspected 

infested ash trees through the Oregon Invasive Species 

HOST: ASH Council’s “Report an Invader” application and phone 

number. Trained agency staff documented their visual 

surveys through a standardized electronic data sheet 

and dashboard. By the end of 2022 approximately 58 

infested trees had been confirmed with approximately 

120 suspected trees nearby. The infested trees all 

occupy approximately a 6-mile-diameter area from the 

initial detection. Washington County was quarantined 

in December 2022. 

In addition to the use of biocontrol agents, a treatment 

strategy known as “Slow Ash Mortality” (or SLAM) 

is being implemented in the Forest Grove area. 

Slowing ash mortality builds time to support survey 

efforts and make management decisions for ash in 

private, community, and forest landscapes. A priority 

for research is to investigate potential replacement 

species for Oregon ash. Seeds from Oregon ash have 

also been collected for safe storage, resistance testing, 

and future restoration efforts.

ÌFirst new State detection since 2018 

occurred in Oregon 

ÌAsh mortality continues in impacted 

States

FOREST PEST DETECTIONS*

First Detected in 2022

First Detected in 2021

First Detected in 2020

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

County Detections as of 10/31/2022

Washington County

*Forest pest detections are recorded at the county level when pest presence is determined and may not be reflective of damage severity.

11 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 12
Aerial view of white fir tree mortality caused by the fir engraver. Photo by William M. Ciesla, Forest Health Management International, Bugwood.org. Grand fir mortality caused by the fir engraver. Photo by Dave Powell, USDA Fir engraver beetle adult. Photo by Dan West, Colorado State Forest Service.

Forest Service, Bugwood.org.

NATIVE

Significant tree 

mortality in all 

species of true fir.

Fir Engraver

Scolytus ventralis

Ongoing drought and extreme summer temperatures 

continued to impact western fir forests. Tree mortality 

caused by the fir engraver continued throughout the 

Western United States in 2022. 

Mortality in fir forests caused by the 

fir engraver was reported on nearly 

3.4 million acres. 

In the Southwest, fir mortality was attributed to the fir 

engraver in Arizona and New Mexico. Arizona observed 

mortality on 43,000 acres of fir predominately on the 

Kaibab National Forest with additional mortality on the 

Coconino National Forest, Coronado National Forest, 

Grand Canyon National Park, and White Mountain 

Apache Tribal lands. New Mexico reported almost 

7,000 acres, double that observed in 2021, of fir 

mortality on the Cibola National Forest and Santa Fe 

National Forest. 

In the Pacific Northwest, tree mortality caused by the 

fir engraver continued, particularly in overstocked 

stands of fir on drought-prone sites and in trees 

infected with root disease. In Oregon, over a million 

acres with damage was reported by aerial detection 

surveys. This level of tree injury has not been recorded 

in over 75 years of aerial detection in Oregon. Many 

forests impacted by the fir engraver are also being 

impacted by chronic hot droughts, root disease, and 

balsam woolly adelgid. Mortality caused by the fir 

engraver is widespread in Washington throughout 

the Cascades.

In California, fir mortality attributed to the fir engraver 

beetle comprised over 77 percent of the total tree 

mortality observed in 2022. The State recorded 

approximately 28.1 million dead firs across almost 2 

million acres. Red fir mortality was most intense and 

widespread throughout the central Sierra Nevada 

Range. Mortality from fir engraver was most severe 

where red fir occurs in mature, fir-dominated stands 

at high elevations. White fir mortality was widespread 

but less severe in mixed conifer stands. Grand fir 

mortality was light to moderate throughout its range 

in northwestern California. 

Surveyors continued to detect the fir engraver across 

Idaho, Montana, Nevada, and Utah. In Utah, 30,000 

acres of fir mortality were attributed to the fir engraver. 

Significant fir mortality was observed around Lake 

Tahoe. The fir engraver beetle continues to impact 

white fir in southern Colorado. Aerial surveys detected 

4,600 acres of fir mortality, most notably around the 

town of Ouray and north of Durango where the 416 

Fire burned in 2018.

HOST: WESTERN FIRS

ÌMortality attributed to fir engraver 

on nearly 3.4 million acres

ÌDrought conditions continue to 

promote fir engraver activity in the 

West

FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

13 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 14
Oak and white pine damage from the spongy moth. Photo by Karla 

Salp, Washington State Department of Agriculture, Bugwood.org.

Spongy moth larva(e). Photo by Karla Salp, Washington State Department of Agriculture, Bugwood.org.

EXOTIC

Significant 

reduction of 

defoliation in 2021. 

Spongy Moth

Lymantria dispar dispar

Defoliation caused by the spongy moth decreased to 

1.8 million acres nationally from 2.5 million acres in 

2021. Spongy moth activity declined significantly in 

Michigan to approximately 370,000 acres compared to 

nearly 1.3 million acres in 2021. 

Defoliation by the spongy 

moth increased dramatically in 

Pennsylvania. 

In New York, the population of the spongy moth 

largely collapsed in 2022 and considerably less damage 

was observed. Localized pockets of severe defoliation 

occurred mainly in Schenectady, Saratoga, and Warren 

Counties. The presence of Nucleopolyhedrosis virus 

(NPV) and Entomophaga maimaiga was high resulting 

in high caterpillar mortality, effectively ending the 

outbreak that began in 2020. 

The spongy moth caused areas of severe defoliation in 

western Massachusetts where more than 30,000 acres 

with defoliation were detected. Vermont reported 

the second year of a spongy moth outbreak affecting 

43,000 acres, predominately in oak forests in western 

Vermont. Connecticut reported more than 76,000 acres 

with defoliation in the western part of the State. No 

defoliation was observed in Rhode Island. 

In Maine, the second year of the spongy moth 

outbreak resulted in approximately 55,000 acres with 

defoliation statewide. Surveyors reported extensive 

damage in southern Oxford County accounting for 

almost all the spongy moth activity in Maine. Damage 

was also reported in smaller pockets across the State. 

An additional 52,000 acres with defoliation was 

reported across the border in New Hampshire. 

The mid-Atlantic States of Delaware, West Virginia, and 

Ohio reported limited to no defoliation by the spongy 

moth. Pennsylvania and New Jersey reported high 

levels of the spongy moth activity with many large 

areas of severe defoliation. The nearly 900,000 acres 

of spongy moth defoliation reported in Pennsylvania 

is almost three times more than reporting in 2021. In 

New Jersey, the spongy moth defoliated more than 

15,000 acres, mostly in the southern part of the State. 

Maryland reported 20,000 acres with defoliation in the 

southeastern part of the State.

The Central States of Iowa, Illinois, Missouri, and 

Minnesota did not report any tree damage from the 

spongy moth. Less than 2,000 acres with defoliation 

were reported from Indiana. In Wisconsin, the spongy 

moth impacted over 117,000 acres—an increase over 

2021. Spongy moth populations collapsed in the 

HOST: HARDWOODS northern Lower Peninsula of Michigan following a 

record defoliation event in 2021. 

In the South, about 25,000 acres with defoliation by the 

spongy moth was reported in Virginia along the spine 

of the Appalachians, the Blue Ridge Mountains, and 

Shenandoah National Park. The spongy moth continued 

to be collected in traps in other Southern States.

Across the Western United States, the Forest Service 

conducted pheromone-based male spongy moth 

trapping surveys in coordinated efforts with USDA’s 

Animal and Plant Health Inspection Service (APHIS) 

and State and Tribal agriculture departments. Annual 

monitoring and detection traps were negative in the 

Western States with three exceptions—Washington, 

Oregon, and Montana. Delimiting trappings in 

response to detections in Western States conducted 

in response to positive catches in previous years were 

negative in 2022.

ÌReduced defoliation reported across 

States heavily impacted in 2021

Ì1.7 million acres with defoliation 

reported predominately in MI and PA

FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

**Federal Quarantine Area – Animal and Plant Health Inspection Service.

Damage in 2022

Damage in 2021

Damage in 2020

Quarantined Counties**

Affected State

Pest Not Yet Detected

Forest Service Region

15 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 16
Extensive whitebark pine mortality caused by white pine blister rust. Photo by Christy Cleaver, USDA Forest Service.

Bright red, recently killed (flagged) branches on limber pine. Photo 

by Christy Cleaver, USDA Forest Service.

Orange spores are produced within canker blisters on white pine 

branch. Photo by USDA Forest Service.

EXOTIC

Whitebark pine, 

a host species, 

is listed as a 

threatened 

species.

White Pine Blister Rust

Cronartium ribicola

HOST: FIVE-NEEDLE PINES

ÌWhitebark pine was designated as 

threatened under the Endangered 

Species Act

ÌWhitebark pine mortality is 

extensive in high-elevation forests 

in the Western United States

FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

In December, the U.S. Department of the Interior’s 

Fish and Wildlife Service listed whitebark pine, which 

occurs in high-elevation areas across the West, as 

threatened under the Endangered Species Act. The 

Species Status Assessment Report concluded that the 

primary damage agent affecting the conservation 

status of whitebark pine is the nonnative fungal 

disease white pine blister rust (WPBR). Additional 

threats to whitebark pine, including mountain pine 

beetle, wildfire, and climate change, have resulted 

in more than 50 percent mortality of whitebark pine 

across its range. 

White pine blister rust, caused by Cronartium ribicola, 

causes cankers on stems, limbs, and branches of 

all North American white pines, including limber, 

whitebark, bristlecone, southwestern white, western 

white, and eastern white. It can be observed on all 

ages of host trees from seedlings and saplings to 

mature trees. Even at low infection rates, branch 

cankers tend to kill cone-bearing branches, reducing 

the seed source for regeneration. 

Disease occurrence in whitebark pine includes 

approximately 500,000 acres above 5,000 feet on the 

high mountain tops in Idaho and Montana, from the 

Canadian border south to Glacier and Yellowstone 

National Parks. In the West, WPBR is most frequently 

found on whitebark and limber pines. Infected western 

white pine and sugar pine were found only along the 

California-Nevada border. 

In Wyoming, field observations in 2021 and 2022 

indicated evidence that a localized “wave-year” event 

had occurred. A “wave-year” is a marked by multiple 

periods of high relative humidity in the summer and 

fall leading to increased WPBR infections detected as 

stem and branch cankers. 

In Washington and Oregon, WBPR is found throughout 

the historic range of western white pine in the 

Olympic, Gifford Pinchot, Mt. Hood, and Willamette 

National Forests. Whitebark pine forests in the same 

national forests are also affected. Sugar pine is 

impacted in southwest Oregon. 

In New Mexico, WPBR infections were found around 

Hillsboro Peak on the Black Range of Gila National 

Forest in Sierra County. This 2022 detection is the 

first detection of WPBR in this mountain range and 

county. The infestation in the Sacramento and White 

Mountains of southern New Mexico is advanced and 

causing widespread crown dieback and mortality. 

In the East, WPBR remains a significant threat to eastern 

white pine regeneration and sapling-sized trees 

and stands throughout the State of Maine wherever 

white pine and its alternate hosts coexist. In Vermont, 

mortality of eastern white pine caused by WPBR was 

mapped by aerial survey throughout the State.

17 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 18
*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

Immature hemlock woolly adelgid crawler emerging from egg mass. Photo by Lorraine Graney, Bartlett Tree Experts, Bugwood.org. Tree decline and mortality caused by the hemlock woolly adelgid. Photo by 

William M. Ciesla, Forest Health Management International, Bugwood.org.

Immobile, white woolly masses at the base of needles on the underside of 

hemlock twig. Photo by Bruce Watt, University of Maine, Bugwood.org.

Hemlock tree mortality caused by the hemlock woolly adelgid. Photo by 

USDA Forest Service.

EXOTIC

An invasive 

threat to eastern 

and Carolina 

hemlocks.

Hemlock Woolly Adelgid

Adelges tsugae

The hemlock woolly adelgid (HWA) is a cryptic 

species with at least 10 distinct genetic lineages, 2 of 

which are considered established in the continental 

United States. In western North America, the linage 

is considered native and does not cause significant 

damage to western hemlocks. In the Eastern United 

States, a different linage established from Japan is 

considered invasive and causes high levels of mortality 

to eastern hemlocks. Introduced in 1951, the HWA 

can now be found throughout the range of hemlock 

in North America. In 2022, the HWA was observed 

causing damage on hemlock across nearly 6,000 acres 

in the East.

In the mid-Atlantic, HWA is found wherever hemlock 

occurs in Ohio, Pennsylvania, West Virginia, Maryland, 

and New Jersey. Several States reported additional 

counties with the HWA. In Maryland, 85 percent of the 

hemlock is located in the westernmost two counties 

and those stands have persistent HWA. In New Jersey, 

almost all the native hemlock in forests, isolated in the 

northwest, has been infested with the HWA. Hemlock 

woolly adelgid is also observed throughout the State 

on ornamental hemlock. Michigan and Indiana have 

observed areas of the HWA. 

In the Northeast, the HWA is found in Connecticut, 

Massachusetts, New York, New Hampshire, Rhode 

Island, and Maine. Throughout this area the HWA is 

persistent and caused varying levels of decline and 

mortality on eastern and ornamental hemlocks. Maine 

identified HWA in several new areas including near 

Acadia National Park in 2022. 

In the South, HWA is found in Alabama, Georgia, 

Kentucky, North Carolina, South Carolina, Tennessee, 

and Virginia. In Georgia and Kentucky, the HWA is 

found across the entire range of hemlock. In South 

Carolina, the HWA threatens eastern and Carolina 

hemlock, a small but important long-lived mountain 

tree species.

HOST: HEMLOCKS

ÌMortality occurs on eastern and 

ornamental hemlocks

ÌReported throughout the range

of hemlock

19 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 20
FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

View of actively wilting oak tree branches caused by the oak wilt disease. Photo by Steven Katovich, Bugwood.org.

Red oak mortality caused by oak wilt. Photo by Joseph O’Brien, USDA Forest 

Service, Bugwood.org.

Leaf discoloration and wilting is a symptom of the oak wilt disease. Photo 

by Ryan Armbrust, Kansas Forest Service, Bugwood.org.

Oak leaves with veinal necrosis. Photo by Ronald F. Billings, Texas A&M 

Forest Service, Bugwood.org.

NATIVE

An aggressive 

wilt disease of 

oaks.

Oak Wilt

Bretziella fagacearum

Oak wilt is an aggressive tree disease that impacts 

oaks. Oak wilt affects both red and white oak species 

killing oaks in forests, woodlots, and community 

landscapes throughout New England and the 

mid-Atlantic, Central, and Southern States of Ohio, 

Pennsylvania, Maryland, West Virginia, New York, Iowa, 

Indiana, Michigan, Missouri, Wisconsin, Minnesota, 

South Carolina, and Texas. 

Oak wilt was widely distributed over Pennsylvania, 

Ohio, Maryland, and West Virginia in 2022. In New 

York, two new sites were detected in Ontario and 

Yates Counties. In West Virginia, 52 of 55 counties 

have reported active oak wilt. In Pennsylvania, 34 out 

of 67 counties have confirmed oak wilt. In Ohio, oak 

wilt infections were identified in several areas with 

many confirmed pockets of infection in northwestern 

and east-central Ohio. In Indiana, 66 of 92 counties 

have confirmed occurrence of oak wilt. Most counties 

without oak wilt are in the east-central part of the 

State, which is predominately agriculture fields with 

limited woodlots and forest areas. 

In Michigan, oak wilt continued to increase within 

the oak resource in the Upper and Lower Peninsulas. 

In Minnesota, no new counties were identified. In 

Missouri, one positive result for oak wilt was reported 

in Henry County. In Wisconsin, oak wilt continues to 

cause pockets of mortality. Oak wilt was also found coinfecting bur oak with bur oak blight.

HOST: OAK

ÌAn aggressive tree disease of red 

oak species

ÌActively spreading among oaks

damaged or trimmed during April, 

May, or June each year

21 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 22
*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

Damage in 2022

Damage in 2021

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

Aerial view of tree mortality caused by the roundheaded pine beetle. Photo by Justin Backsen, USDA Forest Service. Tree mortality caused by the roundheaded pine beetle. Photo by John 

Nelson, USDA Forest Service.

An adult roundheaded pine beetle on a pitch tube is evidence of an attack 

on the host. Photo by Suzanne Marchetti, USDA Forest Service.

Tree mortality caused by the roundheaded pine beetle. Photo by Suzanne 

Marchetti, USDA Forest Service.

NATIVE

Bark beetle 

complexes 

contribute to 

mortality in 

southwestern 

Colorado.

Roundheaded Pine Beetle

Dendroctonus adjunctus

When multiple insects, diseases, and abiotic factors 

combine within a forest ecosystem, the resulting 

changes and tree mortality can be dramatic.

In 2022, the roundheaded pine beetle (RHPB), 

in conjunction with other bark beetles, caused 

approximately 4,500 acres with mortality across the 

area locally known as “the glade.” Beetle expansion has 

moved north towards the edge of the ponderosa forest 

on the Dolores Plateau. Fall ground surveys conducted 

indicate that the RHPB population continues to 

expand, usually in small pockets that grow significantly 

every year. Additional detections of the RHPB were also 

confirmed on the Uncompahgre National Forest.

The RHPB is a native insect that attacks ponderosa 

pine. An epidemic, or outbreak, of primarily RHPB 

began on the San Juan National Forest, CO, in 2014. 

The RHPB is often observed in conjunction with 

other native species of bark beetles, creating a bark 

beetle “complex” that kills trees and can complicate 

forest management. The RHPB was co-occurring in 

ponderosa pine stands with western pine beetle, 

mountain pine beetle, and engraver beetles. Compared 

to other beetles in the complex, RHPB attacks trees 

later in the year, resulting in trees being under attack 

by beetles for much of their growing season. Warmer 

than average temperatures combined with extreme to 

severe drought conditions in southwest Colorado over 

the last several years likely contributed to increased 

tree mortality caused by this bark beetle complex.

HOST: PONDEROSA PINE

ÌBeetles attack host trees in the fall

ÌOver 4,500 acres of mortality in 

southwest Colorado

23 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 24
Bark removal reveals an adult spruce beetle among packed frass. Photo by 

Steve Swenson, USDA Forest Service.

Engelmann spruce mortality caused by the spruce beetle. Photo by USDA Forest Service.

NATIVE

Cumulative tree 

mortality impacts 

high-elevation 

forests across 

range of spruce.

Spruce Beetle

Dendroctonus rufipennis

The spruce beetle continued to cause tree mortality 

across the range of spruce in the Western United States 

from Mew Mexico to Alaska. Several areas reported 

reduced tree mortality in 2022 where mature spruce 

have been depleted from the landscape.

In Alaska, spruce beetle activity was observed on 

roughly 48,800 acres. This is the least spruce beetle 

activity mapped annually since 2015. Nearly all spruce 

beetle activity mapped was in south-central Alaska, 

where the ongoing spruce beetle outbreak is now 

estimated to be in its seventh year. The outbreak has 

affected nearly 1.9 million cumulative acres since 

2016. Activity has declined greatly in areas that were 

impacted most severely early in the outbreak. Tree 

mortality caused by the spruce beetle was observed 

in all or portions of the Denali, Matanuska-Susitna, 

and Kenai Boroughs, as well as the Municipality of 

Anchorage. Ground observations have also confirmed 

mortality of black spruce caused by the spruce beetle. 

Almost 1,900 acres of black spruce 

mortality were attributed to spruce 

beetles in 2022. 

In the interior west, surveys indicated that tree 

mortality caused by spruce beetles remained 

present but was decreasing, with approximately 

29,000 acres reported. In Wyoming, about 14,000 

acres of mapped spruce beetle area occurred on the 

Bridger-Teton National Forest. The Shoshone National 

Forest continued to experience high levels of spruce 

mortality, and activity in Utah continued on the Ashley 

National Forest and Uinta-Wasatch-Cache National 

Forest. Tree mortality caused by the spruce beetle 

is expected to decrease as suitable host material is 

exhausted in the Uinta Mountains. In Montana and 

northern Idaho, tree mortality from spruce beetles was 

very low at less than 250 acres reported. 

In Colorado, tree mortality caused by spruce beetles 

continued to expand where there are suitable hosts, 

particularly in the San Juan National Forest, Gunnison 

National Forest, San Isabel National Forest, Arapahoe 

HOST: SPRUCE

ÌAttacks spruce trees across its 

range in North America

ÌMortality continues across the 

Western United States

FOREST DAMAGE AND RANGE*

and Roosevelt National Forests, and Rocky Mountain 

National Park. Overall acres reported declined in 2022 

to less than 30,000 acres. There are now many large 

areas with ongoing spruce beetle activity that have 

little mature spruce remaining. 

In South Dakota, small groups of the spruce beetle 

are scattered in the northern Bighorns in the Burgess 

Junction area. The Crater Ridge Fire that burned 

in the summer of 2021 in the northwest Bighorn 

National Forest resulted in standing, partially 

scorched Engelmann spruce that were attacked by 

the spruce beetle. 

In Arizona, spruce beetle activity was limited and 

predominately observed on the Kaibab National 

Forest. In New Mexico, the spruce beetle outbreak 

continued to kill Engelmann spruce in spruce-fir forests 

primarily on the Carson National Forest and the Santa 

Fe National Forest and adjacent lands. Some stands 

that have experienced several years of tree mortality 

from spruce beetles have less than 10 percent live 

spruce remaining.

FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

Affected State

Pest Not Yet Detected

Forest Service Region

Damage in 2022

Damage in 2021

Damage in 2020

Previous County Detections

25 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 26
Tree mortality caused by sudden oak death. Photo by Joseph O’Brien, USDA Forest Service, Bugwood.org. Leaf discoloration symptoms from sudden oak death. Photo by Joseph 

O’Brien, USDA Forest Service, Bugwood.org.

Discolored tissue and black zone lines beneath the bark of oak is a symptom of 

sudden oak death. Photo by Bruce Moltzan, USDA Forest Service, Bugwood.org.

Tanoak mortality caused by sudden oak death. Photo by USDA Forest Service.

EXOTIC

Survey and 

monitoring help 

determine where 

to slow the spread. 

Sudden Oak Death

Phytophthora ramorum

HOST: OAK AND TANOAK

ÌCounty-level quarantines in place

in California and Oregon

ÌDetection methods include stream 

baiting

Sudden oak death (SOD), caused by Phytophthora 

ramorum, is known to occur in natural forested areas 

in Oregon and California. It is a federally regulated pest 

with established quarantines in Curry County, OR, and 

the State of California. 

In 2022, no new infestations were detected outside 

of the SOD quarantine area. In California, one new 

satellite infestation was found near the European 

strain (EU1) detection from 2021. In Oregon, the 

current slow-the-spread program uses early detection, 

monitoring, and eradication treatments in areas 

outside the generally infested area to reduce the rate 

of disease spread and slow disease intensification. 

Surveying, detection, and monitoring efforts for 

SOD include ground, aerial, and stream bait surveys. 

Ground-based detection and delimitation surveys 

are conducted year-round near infested sites. Aerial 

surveys, conducted from fixed-winged aircraft and 

helicopter, take place four times per year, and are 

supplemented with high-resolution digital imagery. 

The primary aerial survey occurs when current-year 

tanoak mortality is most visible in July and October. 

Within the SOD quarantine area and in high-risk areas 

outside the quarantine area, a detection method called 

“stream baiting” is used. Stream baiting tests for the 

presence of P. ramorum in waterways, which can aid in 

detection of infested oaks upstream and supports early 

detection and mitigation. 

FOREST DAMAGE AND RANGE* County Detections as of 10/31/2022

*Annual insect and disease surveys are conducted by Forest Health Protection to detect forest pest damage and/or mortality when there are 

concerns about forest pest activity that can cause significant economic and environmental harm.

**Federal Quarantine Area – Animal Plant and Health Inspection Service. Only a portion of Curry County, OR, is included in the quarantined area.

Quarantined Counties**

Affected State

Pest Not Yet Detected

Forest Service Region

27 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 MAJOR FOREST INSECT AND DISEASE CONDITIONS IN THE UNITED STATES: 2022 28