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Regional pressure

Regional Pest Alert Map

Where the major pests and diseases pressuring trees are established across the lower 48, how severe each one is, and when it peaks. Live alerts drop on when new detections and quarantines hit the news. Every marker links straight to diagnosis and treatment.

Pest pressure

66 hotspots across 22 pests & diseases · 60 live alerts

SevereHighModerateLowLive alert
AlabamaArizonaArkansasCaliforniaColoradoConnecticutDelawareDistrict of ColumbiaFloridaGeorgiaIdahoIllinoisIndianaIowaKansasKentuckyLouisianaMaineMarylandMassachusettsMichiganMinnesotaMississippiMissouriMontanaNebraskaNevadaNew HampshireNew JerseyNew MexicoNew YorkNorth CarolinaNorth DakotaOhioOklahomaOregonPennsylvaniaRhode IslandSouth CarolinaSouth DakotaTennesseeTexasUtahVermontVirginiaWashingtonWest VirginiaWisconsinWyoming

Hotspots are the established range centroids from the Pest & Disease library. Hover or tap a marker for detail, click through for treatment. Live alerts current as of Sep 10, 2026.

Live alerts

60 recent developments

SevereQuarantine
Asian longhorned beetle quarantine expanded in Charleston County, South Carolina

USDA APHIS expanded the ALB quarantine in Charleston County, adding 16.5 sq miles in Mount Pleasant and 25.2 sq miles in Hollywood, effective September 4, 2026, following confirmed infested trees found in both areas.

Mount Pleasant and Hollywood, Charleston County, SC
Sep 4, 2026Asian Longhorned Beetle
SevereQuarantine
ALB quarantine boundaries revised in Charleston and Dorchester counties, South Carolina

Clemson University updated Asian longhorned beetle quarantine boundaries effective August 23, 2026, expanding the Hollywood area quarantine and reducing the Mount Pleasant area following six years of eradication work. Survey crews have inspected over 596,000 trees and found 13,140 infested trees.

Charleston and Dorchester Counties, SC
Jul 10, 2026Asian Longhorned Beetle
HighNew detection
Spotted lanternfly population confirmed in Berrien and Washtenaw counties, Michigan

MDARD confirmed a spotted lanternfly population in Berrien County, a major grape-producing region, and a newly confirmed population in Washtenaw County as of September 10, 2026. Confirmed counties now include Berrien, Jackson, Lenawee, Macomb, Monroe, Oakland, Washtenaw and Wayne.

Berrien County, MI
Sep 10, 2026Spotted Lanternfly
HighNew detection
EAB identified for first time in Hayward, Sawyer County, Wisconsin

Emerald ash borer was found in an ash tree near Minnesota Avenue and 4th Street in Hayward, making it the seventh municipality in Sawyer County with a confirmed infestation.

Hayward, Sawyer County, WI
Aug 28, 2026Emerald Ash Borer
HighQuarantine
EAB detected in Bismarck, triggering quarantine in Burleigh County, North Dakota

EAB was found in Bismarck in late August 2026 during ash tree removals, the first detection in central North Dakota. Burleigh County is now under quarantine restricting movement of hardwood firewood and ash material.

Bismarck, Burleigh County, ND
Aug 27, 2026Emerald Ash Borer
HighQuarantine
Box tree moth quarantine imposed on Cape May, Cumberland, and Atlantic Counties, NJ

Box tree moth was first confirmed in New Jersey on June 10, 2026 in Cape May County and later in Cumberland County. By Aug 27, 2026 a quarantine covering Cape May, Cumberland, and Atlantic counties was in place, with all life stages active in southern New Jersey.

Cape May, Cumberland, and Atlantic Counties, NJ
Aug 27, 2026Rutgers Plant and Pest Advisory
HighRange expansion
Parasitoid wasps released in Chisago County as EAB spreads to 60 Minnesota counties

About 8,000 parasitoid wasps were released at Ki-Chi-Saga Park in Chisago County on August 26, 2026 as biological control against EAB. Emerald ash borer is now confirmed in 60 Minnesota counties.

Chisago County, MN
Aug 26, 2026Emerald Ash Borer
HighQuarantine
Box tree moth quarantine expanded to Caroline, Cecil, Kent, and Queen Annes Counties, MD

Maryland expanded its box tree moth quarantine effective Aug 24, 2026 to Caroline, Cecil, Kent, and Queen Anne's counties, bringing the total to eight Maryland counties under quarantine after confirmed infestations.

Caroline, Cecil, Kent, and Queen Annes Counties, MD
Aug 24, 2026Maryland Department of Agriculture
HighQuarantine
Asian longhorned beetle quarantine boundaries revised in Charleston and Dorchester counties, SC

Clemson University announced quarantine boundary revisions in Charleston and Dorchester counties effective August 23, 2026, expanding the Hollywood quarantine area and reducing the Mount Pleasant area based on survey results.

Charleston and Dorchester counties, SC
Aug 23, 2026Asian Longhorned Beetle
HighRange expansion
EAB confirmed in Atoka County, Oklahoma, expanding known state range

Oklahoma Forestry Services reported emerald ash borer in Atoka County, adding to infestations in seven other Oklahoma counties. Officials issued warnings and published an updated EAB map on August 23, 2026.

Atoka County, OK
Aug 23, 2026Emerald Ash Borer
HighRange expansion
Spotted lanternfly now established in all five Rhode Island counties

Rhode Island DEM reported on August 20, 2026 that spotted lanternfly is established statewide, with over 1,000 reports in July and over 1,500 in August, indicating rapidly increasing populations across the state.

Rhode Island (statewide)
Aug 20, 2026Spotted Lanternfly
HighNew detection
EAB confirmed in five new Texas counties in August 2026

Texas A&M Forest Service confirmed emerald ash borer in Delta, Erath, Hardin, Walker, and Wood counties on August 20, 2026, bringing new-county detections in Texas to eight for 2026.

Delta, Erath, Hardin, Walker, and Wood Counties, TX
Aug 20, 2026Emerald Ash Borer
HighQuarantine
EAB confirmed in Vancouver, WA; statewide firewood quarantine initiated

Washington state confirmed emerald ash borer in Vancouver after a specimen was identified in early August 2026. A statewide firewood quarantine was initiated the week of August 19 to contain the outbreak.

Vancouver, WA
Aug 20, 2026Emerald Ash Borer
HighSeasonal outbreak
Spotted lanternfly swarms reported across parts of New Jersey in summer 2026

New Jersey Department of Agriculture reported renewed summer spotted lanternfly infestations across parts of New Jersey as of August 12, 2026. Adults are feeding on sap from over 70 plant species and laying egg masses that fuel recurring outbreaks.

New Jersey (statewide)
Aug 12, 2026Spotted Lanternfly
HighRange expansion
EAB found in 20 Nebraska counties as spread continues statewide

Nebraska's July 2026 forest health report, released August 12, confirmed emerald ash borer in 20 counties, with new counties being added each year as the pest spreads through urban and rural tree populations.

Nebraska (statewide)
Aug 12, 2026Emerald Ash Borer
HighNew detection
EAB detected in Bristol and Jackman, Maine; quarantine expansion planned

Maine DACF reported in an August 11, 2026 bulletin that EAB was found in Bristol, Lincoln County marking the first detection there, and in Jackman, Somerset County, well outside the existing quarantine area. The state indicated the quarantine will be expanded.

Bristol, ME (Lincoln County)
Aug 11, 2026Emerald Ash Borer
HighRange expansion
Spotted lanternfly spreads to 10 communities in Hampshire County, MA

By late July 2026, spotted lanternfly infestations in Hampshire County, Massachusetts grew from 3 communities in August 2025 to 10 cities and towns, with confirmed spread into Sunderland in Franklin County.

Hampshire County, MA
Aug 7, 2026Spotted Lanternfly
HighNew detection
EAB confirmed for first time in Colorado Springs, El Paso County

Larvae found in a dying ash tree in northeast Colorado Springs were confirmed as EAB on Aug 6, 2026, marking the first detection south of Parker and Highlands Ranch in Colorado.

Colorado Springs, El Paso County, CO
Aug 6, 2026Emerald Ash Borer
HighNew detection
Emerald ash borer confirmed in Salem, Beaverton, Rockcreek, and Silverton, Oregon

Oregon Department of Forestry confirmed emerald ash borer in Salem, Beaverton, Bethany Lake Park in Rockcreek, and the Oregon Garden in Silverton in July 2026, announced August 6, 2026. The beetle is now known from five Willamette Valley counties.

Salem, Beaverton, Rockcreek, and Silverton, OR
Aug 6, 2026Emerald Ash Borer
HighQuarantine
Laurel wilt quarantine established across five Suffolk County towns, New York

NY DEC and NY Agriculture and Markets established a laurel wilt quarantine district in Suffolk County covering Huntington, Babylon, Smithtown, Islip, and Brookhaven, announced August 4, 2026. The invasive fungal disease had been confirmed in all five towns.

Suffolk County, NY
Aug 4, 2026LongIsland.com
HighRange expansion
Allegheny County, PA leads state in spotted lanternfly reports in 2026

Allegheny County recorded 104 citizen spotted lanternfly reports from January through June 2026, the highest of any Pennsylvania county. The pest is now confirmed in 56 of Pennsylvania's 67 counties.

Allegheny County, PA
Aug 2, 2026Spotted Lanternfly
HighQuarantine
Box tree moth confirmed and quarantined in Cape May County, NJ

USDA APHIS confirmed box tree moth at private residences in Cape May County, New Jersey, prompting a local quarantine order with movement restrictions on boxwood plants.

Cape May County, NJ
Jul 30, 2026Cape May County Municipal Utilities Authority
HighRange expansion
EAB detected in 16 new Maine municipalities including first detection in Bangor

Since early 2026, emerald ash borer has been confirmed in 16 new Maine municipalities including Bangor (Penobscot County) and Wilton (Franklin County). These represent significant municipal-level range expansions across the state.

Bangor, Penobscot County, ME
Jul 30, 2026Emerald Ash Borer
HighRange expansion
Spotted lanternfly confirmed across nine Hudson Valley counties, New York

As of July 28, 2026, confirmed spotted lanternfly infestations were reported across Columbia, Dutchess, Greene, Orange, Putnam, Rockland, Sullivan, Ulster, and Westchester Counties in New York's Hudson Valley.

Hudson Valley, NY
Jul 28, 2026Spotted Lanternfly
HighNew detection
First known oak wilt case in Monroe County found in town of Greece, New York

New York DEC confirmed oak wilt in a red oak in the town of Greece, Monroe County, in mid-June 2026. Officials removed the infected tree and are monitoring nearby oaks near English Road and Vintage Lane.

Town of Greece, Monroe County, NY
Jul 24, 2026Oak Wilt
HighNew detection
Elm zigzag sawfly first detected in Michigan in St. Clair County

Michigan MDARD confirmed the state's first detection of elm zigzag sawfly in St. Clair County on July 21, 2026, identified from samples submitted by an arborist via the Midwest Invasive Species Information Network.

St. Clair County, MI
Jul 21, 2026Michigan EGLE / MDARD
HighRange expansion
Aerial spongy moth treatments planned across four northern Minnesota counties

Minnesota Department of Agriculture announced aerial treatments for spongy moth infestations in Aitkin, Carlton, Pine, and St. Louis counties starting July 14, 2026, targeting confirmed outbreak sites in northern Minnesota forests.

Aitkin, Carlton, Pine, and St. Louis counties, MN
Jul 14, 2026Spongy Moth
HighNew detection
Spotted lanternfly confirmed in Jackson County, Michigan

On July 10, 2026, Michigan conservation leaders confirmed spotted lanternfly in Jackson County as well as Lenawee, Macomb, Monroe, Oakland, and Wayne counties, reflecting continued range expansion in southeastern Michigan.

Jackson County, MI
Jul 10, 2026Spotted Lanternfly
HighRange expansion
Southern pine beetle outbreaks continue on Cape Cod and islands, Massachusetts

Southern pine beetle outbreaks ongoing since 2023 are continuing in 2026 on Cape Cod, Martha's Vineyard, and Nantucket, targeting pitch pine. Officials urge reporting of suspected infestations amid continued bark beetle pressure.

Cape Cod, Martha's Vineyard, and Nantucket, MA
Jul 10, 2026Southern Pine Beetle
HighNew detection
First mass spotted lanternfly sighting of 2026 reported in Bristol, Tennessee

On July 6, 2026, WCYB reported the first mass sighting of spotted lanternfly in Bristol, Sullivan County, Tennessee. Tennessee Department of Agriculture has officially detected SLF in six Tennessee counties so far in 2026.

Bristol, Sullivan County, TN
Jul 6, 2026Spotted Lanternfly
HighNew detection
EAB detected north of Mapleton in Cass County, North Dakota

On July 2, 2026, North Dakota Forest Service confirmed a second EAB detection in Cass County, north of Mapleton and more than 12 miles from the first find in Fargo, indicating local range expansion.

North of Mapleton, Cass County, ND
Jul 2, 2026Emerald Ash Borer
HighQuarantine
Laurel wilt quarantine district established in Suffolk County, New York

New York DEC and Agriculture and Markets announced a laurel wilt quarantine district covering Huntington, Babylon, Smithtown, Islip, and Brookhaven in Suffolk County following disease confirmation in August 2025. The quarantine restricts movement of sassafras, spicebush, and untreated firewood.

Suffolk County, NY
Jul 1, 2026New York State DEC
HighRange expansion
Spotted lanternfly fully established throughout Fairfax County, Virginia

Fairfax County reports that spotted lanternfly, first detected in western Fairfax County in 2022, is now found throughout the county. Officials state that sighting reports are no longer needed due to the established population.

Fairfax County, VA
Jul 1, 2026Spotted Lanternfly
HighRange expansion
Spotted lanternfly now documented in 56 of 67 Pennsylvania counties

As of mid-2026, spotted lanternfly has been documented in 56 of Pennsylvania's 67 counties, showing continued spread across the state since the pest's first detection in Berks County in 2014.

Pennsylvania (statewide, 56 counties)
Jul 1, 2026Spotted Lanternfly
HighNew detection
Spotted lanternfly recorded for first time in Marion County, Ohio

On July 1, 2026, the first spotted lanternfly sighting in Marion County, Ohio was reported. Ohio is under a statewide SLF quarantine, and the insect continues to appear in new locations statewide.

Marion County, OH
Jul 1, 2026Spotted Lanternfly
HighQuarantine
Box tree moth found in Rio Grande triggers Cape May County boxwood quarantine

New Jersey confirmed box tree moth at residences in Rio Grande, Middle Township, Cape May County, in June 2026, placing the county under a boxwood quarantine restricting movement of plant material.

Rio Grande, Cape May County, NJ
Jun 1, 2026Cape May County Herald
HighQuarantine
Statewide spotted lanternfly quarantine in effect across all Maryland counties

The Maryland Secretary of Agriculture issued a quarantine order covering all 23 Maryland counties and Baltimore City. A March 2026 infestation ranking shows heavily infested areas in Baltimore City and central Maryland counties including Baltimore, Howard, and Prince George's.

Maryland (statewide)
Mar 1, 2026Spotted Lanternfly
HighQuarantine
Ohio implements statewide spotted lanternfly quarantine in February 2026

In February 2026, the Ohio Department of Agriculture implemented a statewide quarantine for spotted lanternfly following its spread across multiple counties. Trap installation at parks in Beavercreek, Greene County was planned for July 2026.

Beavercreek, Greene County, OH
Feb 1, 2026Spotted Lanternfly
HighNew detection
EAB newly detected in Young, Montague, and Clay counties, Texas

Texas A&M Forest Service confirmed emerald ash borer in Young, Montague, and Clay counties after adult beetles were captured in monitoring traps. These are new county records expanding EAB's known presence in north-central Texas.

Young County, TX
Jan 1, 2026Emerald Ash Borer
HighQuarantine
Oak wilt quarantine district active in Ontario and Yates counties, New York

NYS DEC maintains an oak wilt quarantine district in parts of Ontario County towns Bristol, South Bristol, and Naples, and Yates County towns Middlesex and Italy, based on confirmed infection centers identified in 2025, restricting oak material movement.

Ontario and Yates counties, NY (Finger Lakes region)
Jan 1, 2026Oak Wilt
HighRange expansion
Southern pine beetle outbreak continues on Cape Cod, Martha's Vineyard, and Nantucket

An ongoing southern pine beetle outbreak that began in 2023 continues in eastern Massachusetts, affecting pitch pine on Cape Cod, Martha's Vineyard, and Nantucket. The outbreak remains active as of mid-2026.

Cape Cod, MA
RecentSouthern Pine Beetle (Pine Bark Beetle)
HighQuarantine
Box tree moth confirmed in Rio Grande, Cape May County, New Jersey

Cape May County was placed under a boxwood quarantine after box tree moths were confirmed at private residences in Rio Grande. Officials said the county would remain under quarantine for at least several years.

Rio Grande, Cape May County, NJ
RecentCape May County Herald
ModerateQuarantine
Spotted lanternfly quarantine in effect across multiple northeastern Pennsylvania counties

Luzerne, Lackawanna, Wyoming, Bradford, Sullivan, and Venango counties remain under spotted lanternfly quarantine. As of September 4, 2026, Pennsylvania had not added any new counties to the quarantine list in 2026.

Luzerne and Lackawanna Counties, PA
Sep 4, 2026Spotted Lanternfly
ModerateNew detection
Verticillium wilt killing American elms in Massachusetts, UMass Extension reports

UMass Extension documented Verticillium wilt on American elm in Massachusetts, confirmed by lab culture of symptomatic branches as of September 3, 2026. The report warns Verticillium can kill American elms, especially when combined with drought stress.

Massachusetts
Sep 3, 2026Verticillium Wilt
ModerateSeasonal outbreak
Significant giant tar spot outbreak on Norway maple reported across Massachusetts

UMass Extension reported a significant outbreak of giant tar spot caused by Rhytisma acerinum on Norway maple in Massachusetts, with the disease causing premature leaf shedding especially in shaded trees. The report was published September 3, 2026.

Massachusetts
Sep 3, 2026UMass Amherst Extension
ModerateUpdate
Ohio removes about 4,000 acres from ALB quarantine in Clermont County

Ohio Department of Agriculture and USDA released roughly 4,000 acres in Tate Township, Clermont County from the ALB quarantine on August 23, 2026. About 37.8 square miles in the county remain under quarantine.

Tate Township, Clermont County, OH
Aug 23, 2026Asian Longhorned Beetle
ModerateQuarantine
Ohio extends statewide spotted lanternfly quarantine in 2026

Ohio extended a statewide spotted lanternfly quarantine in February 2026, restricting movement of trees and nursery stock. Franklin County has been under quarantine since 2023 and continues to report active infestations.

Franklin County, OH
Aug 11, 2026Spotted Lanternfly
ModerateRange expansion
Forest tent caterpillar defoliation rises to 60,000 acres in Aitkin County, MN

Minnesota DNR reported on August 10, 2026 that forest tent caterpillars damaged about 60,000 acres of trees in Aitkin County and surrounding counties, up from 41,200 acres in 2025. A larger outbreak in 2027 is being monitored.

Aitkin County, MN
Aug 10, 2026KAXE/KBXE
ModerateUpdate
Michigan issues statewide alert for Asian longhorned beetle during Tree Check Month

Michigan Invasive Species Program and USDA APHIS issued a statewide alert on August 10, 2026 urging residents to check trees for Asian longhorned beetle signs including round exit holes and bark scars. August is designated Tree Check Month for heightened surveillance.

Michigan (statewide)
Aug 10, 2026Asian Longhorned Beetle
ModerateRange expansion
Severe spruce budworm defoliation reported in Oneida and Vilas Counties, Wisconsin

Spruce budworm caused severe defoliation in northeastern Oneida County and southeastern Vilas County as of Aug 5, 2026, with budworms expanding onto hemlock and tamarack near Sugar Camp, Oneida County.

Oneida and Vilas Counties, WI
Aug 5, 2026Wisconsin DNR Forestry News
ModerateQuarantine
APHIS expands box tree moth quarantine to seven Ohio counties

Effective August 4, 2026, USDA APHIS added Ashtabula, Clark, Cuyahoga, Lake, Lorain, Lucas, and Preble Counties, Ohio to the federal box tree moth quarantined area following confirmed detections in 2025.

Multiple Ohio Counties (Cuyahoga, Lake, Lorain, Lucas, Clark, Preble, Ashtabula)
Aug 4, 2026USDA APHIS
ModerateUpdate
ALB quarantine area reduced by 7.4 square miles in Nassau and Suffolk Counties, NY

USDA APHIS removed 7.4 square miles from the Asian longhorned beetle quarantine in Nassau and Suffolk Counties, New York on July 30, 2026, following completed host-tree surveys and eradication activities. Portions of the quarantine in both counties remain in effect and eradication continues.

Nassau and Suffolk Counties, NY
Jul 30, 2026Asian Longhorned Beetle
ModerateRange expansion
Spotted lanternfly population expanding in Fairfield County, Connecticut

Environmental experts reported on July 24, 2026 that spotted lanternfly populations are increasing across Connecticut, with Fairfield County first affected in 2020 and the insect now spreading more widely.

Fairfield County, CT
Jul 24, 2026Spotted Lanternfly
ModerateNew detection
Oak wilt confirmed in Arlington, Tarrant County, Texas

The City of Arlington announced a confirmed oak wilt case in Arlington, Tarrant County in July 2026. Officials are advising residents on management practices and restrictions on pruning and wood movement to prevent spread.

Arlington, Tarrant County, TX
Jul 1, 2026Oak Wilt
ModerateSeasonal outbreak
Spotted lanternfly nymphs active statewide across Maryland under quarantine

A June 26, 2026 notice states spotted lanternfly nymphs are active throughout much of Maryland under an existing statewide quarantine. Residents are urged to destroy nymphs and report sightings to the Maryland Department of Agriculture.

Maryland (statewide)
Jun 26, 2026Spotted Lanternfly
ModerateNew detection
Box tree moth detected in Barnstable and Norfolk counties, Massachusetts

A June 26, 2026, UMass Extension update confirmed box tree moth in several Barnstable County communities and in Brookline, Norfolk County, prompting guidance for residents to report suspected finds.

Barnstable County and Brookline, Norfolk County, MA
Jun 26, 2026UMass Extension Landscape Message
ModerateSeasonal outbreak
Spotted lanternfly egg hatch and nymph activity documented in Worcester and Hampshire counties, MA

Massachusetts MDAR recorded SLF egg hatch in Worcester County as of May 8, 2026 and nymphs active on cultivated grapes in Belchertown, Hampshire County as of June 3, 2026. Nymph abundance increased on tree-of-heaven at UMass Amherst through June 17, 2026.

Worcester County, MA
Jun 19, 2026Spotted Lanternfly
ModerateQuarantine
Spongy moth quarantine expanded to Green and Sawyer counties, Wisconsin

USDA APHIS and Wisconsin added Green County and Sawyer County to the spongy moth quarantine area effective May 1, 2026, expanding the regulatory footprint in the state.

Green County and Sawyer County, WI
May 1, 2026Spongy Moth
LowSeasonal outbreak
Aspen leaf beetle defoliating young aspens in Vilas and Oneida counties, WI

Wisconsin forestry officials reported in early August 2026 that aspen leaf beetles were causing light to moderate defoliation of young quaking aspens in Vilas and Oneida counties, with scattered young white pines also experiencing significant defoliation.

Vilas and Oneida Counties, WI
Aug 1, 2026Wisconsin Department of Natural Resources
LowSeasonal outbreak
Fire blight observed in Massachusetts orchard in late June 2026

UMass Extension reported a minor fire blight outbreak in a Massachusetts orchard in its June 26, 2026 landscape message, with apple and peach trees affected. No specific city or county was named.

Massachusetts (unspecified location)
Jun 26, 2026Fire Blight
Tracked pests & diseases

14 high-priority threats tracked

Browse all entries
Severe6 entries
Severe
Asian Longhorned Beetle
Anoplophora glabripennis
Localized eradication zones in the Northeastern and Midwestern United States
Peak: Adults active and emerging July through October
Worcester, MA · Long Island / NYC, NY · Clermont County, OH
pestView treatment
Severe
Dutch Elm Disease
Ophiostoma novo-ulmi
Throughout the native range of American elm in the United States and Canada
Peak: Symptoms appear late spring through summer; bark beetle vectors active spring–fall
Minneapolis, MN · Denver, CO · Toronto-border / Buffalo, NY
fungusView treatment
Severe
Emerald Ash Borer
Agrilus planipennis
Eastern, central, and expanding western United States and southern Canada
Peak: Adults fly and lay eggs late May through August; larvae feed under bark spring–fall
Detroit, MI (introduction epicenter) · Chicago, IL · Pittsburgh, PA
pestView treatment
Severe
Hemlock Woolly Adelgid
Adelges tsugae
Eastern United States from the southern Appalachians to New England
Peak: Woolly masses most visible fall through spring; two generations feed Oct–June
Great Smoky Mountains, TN/NC · Shenandoah / Blue Ridge, VA · Catskills / Hudson Valley, NY
pestView treatment
Severe
Oak Wilt
Bretziella fagacearum
Eastern and central United States; severe in the Upper Midwest and central Texas
Peak: Spring and early summer (high infection risk from fresh wounds April–July)
Austin / Texas Hill Country, TX · Minneapolis–St. Paul, MN · Madison, WI
fungusView treatment
Severe
Southern Pine Beetle (Pine Bark Beetle)
Dendroctonus frontalis
Southeastern United States, expanding north; related bark beetles range across the West
Peak: Multiple generations spring through fall; outbreaks peak in summer droughts
Atlanta / north GA · Pine Barrens, NJ · East Texas piney woods
pestView treatment
High8 entries
High
Armillaria Root Rot
Armillaria spp.
Throughout the United States and Canada; a widespread soilborne root pathogen
Peak: Decline visible in summer drought stress; honey mushrooms appear in fall
Seattle, WA · Sierra Nevada, CA · Asheville / southern Appalachians, NC
fungusView treatment
High
Bacterial Leaf Scorch
Xylella fastidiosa
Eastern, southeastern, and central United States (xylem-feeding insect vectors)
Peak: Symptoms most visible mid-summer to fall (July–October)
Washington, DC metro · Philadelphia, PA · Charlotte, NC
diseaseView treatment
High
Bronze Birch Borer
Agrilus anxius
Northern United States and Canada, throughout the range of birches
Peak: Adults emerge and lay eggs late May through July; larvae tunnel under bark
Minneapolis, MN · Denver, CO · Chicago, IL
pestView treatment
High
Fire Blight
Erwinia amylovora
Throughout the United States wherever rosaceous trees grow; worst in warm, humid spring weather
Peak: Bloom through early summer, during warm, wet, humid weather
Yakima Valley, WA · Kansas City, MO · Raleigh, NC
diseaseView treatment
High
Spongy Moth (formerly Gypsy Moth)
Lymantria dispar
Northeastern and Great Lakes United States and eastern Canada, spreading south and west
Peak: Caterpillars feed and defoliate May–June; egg masses laid mid-summer overwinter
Hartford / central CT · Boston, MA · Grand Rapids, MI
pestView treatment
High
Spotted Lanternfly
Lycorma delicatula
Mid-Atlantic and Northeastern United States, spreading west and south
Peak: Nymphs spring–summer; conspicuous winged adults July–November; eggs overwinter
Reading / Berks County, PA (US epicenter) · Philadelphia, PA · Newark / northern NJ
pestView treatment
High
Thousand Cankers Disease
Geosmithia morbida (vectored by Pityophthorus juglandis)
Western United States and pockets of the East and Midwest where black walnut grows
Peak: Beetles active and galleries expand spring through fall; dieback shows in summer
Denver / Front Range, CO · Knoxville, TN · Boise, ID
fungusView treatment
High
Verticillium Wilt
Verticillium dahliae / Verticillium albo-atrum
Throughout the United States; a soilborne fungus persisting for years in soil
Peak: Symptoms appear in summer, often after heat or drought stress (June–September)
Columbus, OH · Minneapolis, MN · Portland, OR
fungusView treatment
Moderate6 entries
Moderate
Anthracnose
Apiognomonia / Discula / Colletotrichum spp.
Throughout the United States; worst in regions with cool, wet spring weather
Peak: Spring, during cool, wet, rainy weather at and just after leaf-out
Portland, OR · Washington, DC · Nashville, TN
fungusView treatment
Moderate
Apple Scab
Venturia inaequalis
Cool, humid regions of the United States and Canada, especially the Northeast and Upper Midwest
Peak: Primary infections in cool, wet spring weather (bud break through early summer)
Hudson Valley, NY · Grand Rapids, MI · Boston, MA
fungusView treatment
Moderate
Bagworms
Thyridopteryx ephemeraeformis
Eastern and central United States, particularly the Midwest and Southeast
Peak: Larvae feed and enlarge bags June–August; bags overwinter with eggs
Kansas City, MO · St. Louis, MO · Oklahoma City, OK
pestView treatment
Moderate
Cankerworm (Inchworm)
Alsophila pometaria / Paleacrita vernata
Eastern and central United States and southern Canada
Peak: Larvae feed and defoliate in spring (April–May) as leaves expand
Charlotte, NC · Richmond, VA · Boston, MA
pestView treatment
Moderate
Cytospora Canker
Cytospora / Leucostoma spp.
Throughout the United States; attacks stressed, drought- or winter-injured trees
Peak: Cankers expand in spring and fall; symptoms most visible in summer dieback
Denver, CO · Salt Lake City, UT · Minneapolis, MN
fungusView treatment
Moderate
Scale Insects
Coccoidea (various species)
Throughout the United States on a wide range of trees and shrubs
Peak: Vulnerable mobile 'crawlers' emerge late spring–summer (species dependent)
Atlanta, GA · Houston, TX · Long Island, NY
pestView treatment
Low2 entries
Diagnose & treat

Every marker traces back to a full diagnostic entry.

Symptoms, range, peak season, severity and treatment options — cross-linked to the tree species each pest attacks. The library is the source this map reads from.