Tree pests and dying trees

What is killing the trees

Seventeen agents, fifty states, and the quarantine table almost every article on this subject gets wrong. Built from the forest health report your own state publishes every year, plus a live read of where people are photographing these things right now.

Tens of millions

Ash trees lost

USDA APHIS, on emerald ash borer

38 and DC

States with EAB detected

APHIS, as of April 23, 2026

Federal quarantines still live

and emerald ash borer is not one of them

State pages

each built on that state’s own report

The correction

The federal emerald ash borer quarantine does not exist

If you have read anything about ash trees in the last five years it probably showed you a map of quarantined counties. That map is a historical document. APHIS revoked the domestic emerald ash borer quarantine by final rule and redirected the programme into biological control, releasing parasitoid wasps instead of policing wood movement. Here it is in the agency’s own words, from its current emerald ash borer page:

APHIS removed its domestic EAB quarantine regulations in 2020. The final rule was effective January 14, 2021.

USDA APHIS, Emerald Ash Borer as of April 23, 2026

That is not the same as saying the beetle stopped mattering. The same page states that APHIS has “detected EAB infestations in 38 States and the District of Columbia”. What changed is who is responsible: in the absence of federal regulation, states are free to set their own rules for moving ash material, and several did. Meanwhile the quarantines people have never heard of are the ones still being amended by federal order.

Federal domestic quarantine status, checked against the issuing agency on August 28, 2026. Boundaries move by federal order several times a year, so check the agency rather than this table.
Agent	Federal status	What that means
Emerald ash borer	REPEALED	Removed by final rule 85 FR 81085, effective January 14, 2021. Federal effort moved to biological control. Some states kept quarantines of their own.
Asian longhorned beetle	ACTIVE	7 CFR 301.51. Massachusetts, New York, Ohio and South Carolina. Last amended July 30, 2026.
Spongy moth	ACTIVE	7 CFR part 301. Twenty states and the District of Columbia. Last amended April 15, 2026, adding two Wisconsin counties.
Sudden oak death	ACTIVE	7 CFR 301.92. Sixteen California counties and Curry County, Oregon.
Spotted lanternfly	NONE FEDERAL	No federal quarantine at all. State quarantines only, and they are redrawn most years.

What the states did next, which is the part nobody covers

Repealing the federal rule did not repeal the problem, and the fifty states went in different directions with it. Some had already gone first: Nebraska dropped its own quarantine eleven weeks before APHIS dropped the national one, and its agency page states the whole situation as clearly as any in the country.

The Nebraska Department of Agriculture (NDA) rescinded the Nebraska EAB quarantine on October 29, 2020. USDA rescinded the federal EAB quarantine on January 14, 2021. However, a number of states continue to maintain state EAB quarantine or firewood specific quarantines.

Nebraska Department of Agriculture, Emerald Ash Borer

Others followed the federal retreat and kept going. Tennessee dropped three forest pest quarantines in a single year, and Virginia went further than any other infested state by repealing its spotted lanternfly quarantine outright, which is the opposite of what everyone assumes those orders do.

In 2021, TDA repealed the existing Emerald Ash Borer, Pine Beetle, and Thousand Cankers Disease Quarantines. Currently TN has two plant pest exterior quarantines for boxwood blight and firewood.

Tennessee Department of Agriculture, Plant Pests and Quarantines

As of March 27, 2025, Virginia's spotted lanternfly quarantine has been repealed. This means that businesses moving regulated articles within Virginia are no longer required to hold a permit.

Virginia Department of Agriculture and Consumer Services, Spotted Lanternfly

The practical consequence for a reader is small and specific: there is no national rule about moving ash wood any more, and whether there is a rule where you are is a question with fifty different answers that change without much publicity. The state page for your state links the agency that would know, and that agency publishes the current boundary.

A fallen ash log with the bark gone, covered in winding S shaped larval tunnels and small dark exit holes — The record of an infestation, on a dead ash in southeastern Wisconsin that fell and lost its bark. Every winding channel is one larva that ate its way around the trunk under the bark. The small dark holes are where the adults left. “Bore remnants” by TheLostPariah, CC BY 4.0

The agents

What actually kills trees in America

Seventeen, chosen because people search for them by name or because a quarantine attaches to them. Half of the country’s tree mortality is not on this list at all: it is drought, storms, root damage from construction and old age, and in the western half of the country in particular the beetle is usually the finisher rather than the cause.

Emerald ash borer

Agrilus planipennis

Federal quarantine repealed

The reason the ash trees died. A half inch metallic green beetle whose larvae girdle the tree from the inside.

Kills: Ash (Fraxinus), and white fringetree
When you would notice it: May 15 to Sep 1: adult beetles, and thinning in the top of the crown. Then again Nov 1 to Mar 31: blonde bark where woodpeckers have stripped it, plus D shaped exit holes, both far easier to see with the leaves off.
Photographed in the United States: 4,362 research grade iNaturalist records, all time

Commonly confused with Every metallic green beetle in the Midwest gets reported as emerald ash borer, and most of them are six spotted tiger beetles or Japanese beetles. The tell is the tree, not the beetle: emerald ash borer is only ever on ash.

Spotted lanternfly

Lycorma delicatula

State quarantines only

The one people actually see. A planthopper that swarms trunks by the hundred and rains sticky honeydew on everything under it.

Kills: Rarely kills mature trees outright. Kills tree of heaven and grapevine, and stresses maple, walnut, birch and willow
When you would notice it: Jul 15 to Nov 15: adults, in numbers, on trunks and fences. Then again Oct 1 to May 15: egg masses on any hard surface, which is the stage that hitches a ride on your car.
Photographed in the United States: 91,063 research grade iNaturalist records, all time

Commonly confused with A lanternfly on your maple is not what is killing your maple. It is a real quarantine pest and a genuine nuisance, and it is also the thing people blame for damage that turns out to be drought, girdling roots or construction.

Hemlock woolly adelgid

Adelges tsugae

Not federally quarantined

White woolly dots on the underside of hemlock needles. The tree starves over several years and does not come back on its own.

Kills: Eastern and Carolina hemlock (Tsuga)
When you would notice it: Nov 1 to Apr 30: the white woolly egg sacs, which stand out most on bare winter branches.
Photographed in the United States: 7,880 research grade iNaturalist records, all time

Commonly confused with The woolly dots are easy to mistake for spider egg sacs or scale. Position is the tell: adelgid sits at the base of a needle, on the underside of the twig, in rows.

Beech leaf disease

Litylenchus crenatae

Not federally quarantined

Dark bands between the veins of a beech leaf, visible from underneath against the sky. First recorded in Ohio in 2012 and moving fast.

Kills: American beech (Fagus grandifolia), and ornamental European beech
When you would notice it: May 1 to Jul 31: dark interveinal banding on newly expanded leaves, seen from below looking up.
Photographed in the United States: 8,003 research grade iNaturalist records, all time

Commonly confused with Banded beech leaves look enough like drought scorch or anthracnose that people wave them off. The difference is geometry: beech leaf disease bands follow the veins in stripes, and they are darkest looking up through the leaf.

Spongy moth

Lymantria dispar

Federally quarantined

The caterpillar that eats a whole oak ridge bare in June, formerly called the gypsy moth. Still federally quarantined, and the boundary still moving.

Kills: Oak above all, plus aspen, birch, apple and many others. Repeated defoliation kills
When you would notice it: May 15 to Jul 15: caterpillars, frass falling like rain, and bare crowns in high summer. Then again Aug 1 to Apr 30: tan felt egg masses on trunks, walls, grills and wheel wells.
Photographed in the United States: 28,732 research grade iNaturalist records, all time

Commonly confused with A defoliated oak in June looks dead and usually is not. Healthy oaks refoliate. It is the second and third consecutive year, especially with drought on top, that kills them.

Asian longhorned beetle

Anoplophora glabripennis

Federally quarantined

The one the federal government is still actively trying to eradicate, tree by tree, in four states.

Kills: Maple above all, plus birch, elm, willow, horsechestnut
When you would notice it: Jul 1 to Oct 15: adults, which are large, glossy black with white spots and antennae longer than the body.
Photographed in the United States: 45 research grade iNaturalist records, all time

Commonly confused with Whitespotted pine sawyer is the common native beetle people mistake for it. If it is on a conifer it is not Asian longhorned beetle.

Oak wilt

Bretziella fagacearum

Not federally quarantined

A fungus that plugs an oak's water vessels. A red oak can go from green to bare in a few weeks in midsummer.

Kills: Red oak group fast, white oak group slowly
When you would notice it: Jun 1 to Aug 31: a single oak browning from the top down and shedding half green leaves while its neighbours stay green.
Photographed in the United States: 30 research grade iNaturalist records, all time

Commonly confused with Oak wilt, bur oak blight, anthracnose and plain drought all brown an oak. Only a laboratory can tell you which, and this is the single most common case where a homeowner needs a diagnosis before a decision.

Laurel wilt

Harringtonia lauricola

Not federally quarantined

A beetle the size of a sesame seed carries a fungus that kills a redbay in weeks. It has taken out redbay across the coastal South.

Kills: Redbay, swampbay, sassafras, avocado, and the rest of the laurel family
When you would notice it: Apr 1 to Oct 31: wilted brown foliage that stays hanging on the tree instead of dropping.
Photographed in the United States: 33 research grade iNaturalist records, all time

Commonly confused with Wilted leaves that stay on the tree is the diagnostic detail. Most dying trees drop their leaves; a laurel wilt redbay holds a full brown canopy for months.

Thousand cankers disease

Geosmithia morbida

Not federally quarantined

Thousands of tiny cankers, each around one beetle tunnel, that merge until the branch dies. Named for the arithmetic.

Kills: Black walnut and other walnuts (Juglans)
When you would notice it: Jul 1 to Sep 30: yellowing and thinning in the upper crown of a walnut, then branch by branch dieback over several years.
Photographed in the United States: No research grade iNaturalist records, which is a statement about photographers rather than about the pest

Commonly confused with Walnut anthracnose yellows and drops leaves every August in humid country and alarms people annually. Thousand cankers kills from the top down and does not recover.

Southern pine beetle

Dendroctonus frontalis

Not federally quarantined

A native beetle the size of a rice grain that in outbreak years kills pine by the stand, in expanding spots visible from the air.

Kills: Loblolly, shortleaf, Virginia and pitch pine
When you would notice it: Jun 1 to Oct 31: popcorn sized pitch tubes on the trunk, then a crown that fades yellow and then red.
Photographed in the United States: 92 research grade iNaturalist records, all time

Commonly confused with Ips engraver beetles and black turpentine beetle also attack stressed pines and are far more common in a drought year. Southern pine beetle is the one that kills healthy trees in expanding spots.

Dutch elm disease

Ophiostoma novo-ulmi

Not federally quarantined

The one that already happened. It removed the American elm from the American street between the 1930s and the 1970s and it is still here.

Kills: American elm, and other elms to varying degrees
When you would notice it: Jun 1 to Aug 31: flagging: one branch high in the crown yellowing and wilting while the rest of the tree is green.
Photographed in the United States: 1 research grade iNaturalist records, all time

Commonly confused with Elm yellows, elm leaf beetle and simple drought all yellow an elm. Flagging, one branch at a time from the top, is the classic Dutch elm pattern.

Beech bark disease

Cryptococcus fagisuga with Neonectria

Not federally quarantined

A scale insect first, then a fungus through the wounds it makes. Not the same thing as beech leaf disease, and the two now overlap.

Kills: American beech
When you would notice it: Sep 1 to Apr 30: a white waxy crust on the trunk, then sunken cankers, then a snapped stem in a wind event.
Photographed in the United States: 803 research grade iNaturalist records, all time

Commonly confused with Beech bark disease is on the TRUNK and beech leaf disease is on the LEAF. They are unrelated organisms with similar names attacking the same tree in the same forests, and confusing them is the most common mistake in this whole subject.

Sudden oak death

Phytophthora ramorum

Federally quarantined

The West Coast answer to "what is killing my oak". A water mould, federally quarantined, and there is no cure.

Kills: Tanoak and coast live oak above all, plus over a hundred other hosts
When you would notice it: Apr 1 to Sep 30: dark bleeding seeps on the lower trunk, then a whole crown browning over a few weeks in summer.
Photographed in the United States: 245 research grade iNaturalist records, all time

Commonly confused with The name is a lie about the timing. The tree has usually been infected for a year or more; what is sudden is the browning, not the disease.

Mountain pine beetle

Dendroctonus ponderosae

Not federally quarantined

The native beetle behind the red hillsides of the Interior West. Drought and warm winters are what turn it from background noise into an outbreak.

Kills: Lodgepole, ponderosa, limber and whitebark pine
When you would notice it: Jun 1 to Sep 30: pitch tubes and boring dust in bark crevices this year, red needles next year.
Photographed in the United States: 31 research grade iNaturalist records, all time

Commonly confused with Every red conifer in the Rockies gets called beetle kill. Drought, root disease, dwarf mistletoe and simple old age all do it too.

Spruce beetle

Dendroctonus rufipennis

Not federally quarantined

The dominant killer of spruce from Alaska to Colorado, and the one whose outbreaks track warm summers most clearly.

Kills: White, Engelmann, Sitka and Lutz spruce
When you would notice it: Jun 1 to Sep 30: reddish boring dust at the base of the trunk, and a crown fading to grey rather than red.
Photographed in the United States: 63 research grade iNaturalist records, all time

Commonly confused with A spruce crown killed by beetles goes grey, not red, which is why people miss it for a season longer than they miss mountain pine beetle.

Rapid ohia death

Ceratocystis lukuohia and C. huliohia

Not federally quarantined

Two fungi that can brown a whole ohia crown in a matter of days. It has killed more than a million trees on Hawaii Island.

Kills: Ohia lehua (Metrosideros polymorpha), the foundation tree of Hawaiian forest
When you would notice it: Jan 1 to Dec 31: a crown that browns from healthy to dead in days to weeks, holding its leaves.
Photographed in the United States: 2 research grade iNaturalist records, all time

Commonly confused with Ohia drop their leaves in drought too. The rapid ohia death pattern is a crown that browns and KEEPS its leaves.

Goldspotted oak borer

Agrilus auroguttatus

Not federally quarantined

Southern California's own Agrilus, a close relative of the emerald ash borer, doing to oaks what that one did to ash.

Kills: Coast live oak, California black oak, canyon live oak
When you would notice it: May 1 to Sep 30: D shaped exit holes, dark staining and weeping on the trunk, and thinning in the crown.
Photographed in the United States: 31 research grade iNaturalist records, all time

Commonly confused with A D shaped exit hole means an Agrilus, not specifically an emerald ash borer. On an oak in southern California it means this one.

The calendar

When you would notice each one

The answers here are less obvious than people expect, and several of the best windows are in winter. A hemlock owner who looks in July sees nothing; the same person in February sees white woolly dots along the underside of every twig. A darker band is the main window and a lighter one is a second window, usually a sign on the bark rather than the organism itself.

When in the year you would actually notice each one. A second, lighter band is a second window: several of these are easiest to spot in winter, when the leaves are off and the sign is on the bark.
Agent	J	F	M	A	M	J	J	A	S	O	N	D
Ash borer	second window	second window	second window	not typically visible	main window	main window	main window	main window	main window	not typically visible	second window	second window
Lanternfly	second window	second window	second window	second window	second window	not typically visible	main window	main window	main window	main window	main window	second window
Adelgid	main window	main window	main window	main window	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window
Beech leaf	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible
Spongy moth	second window	second window	second window	second window	main window	main window	main window	second window	second window	second window	second window	second window
Longhorned beetle	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window	not typically visible	not typically visible
Oak wilt	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	not typically visible	not typically visible	not typically visible	not typically visible
Laurel wilt	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window	main window	main window	main window	not typically visible	not typically visible
Thousand cankers	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	not typically visible	not typically visible	not typically visible
Pine beetle	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window	main window	not typically visible	not typically visible
Dutch elm	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	not typically visible	not typically visible	not typically visible	not typically visible
Beech bark	main window	main window	main window	main window	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window
Sudden oak death	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window	main window	main window	not typically visible	not typically visible	not typically visible
Mountain pine beetle	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window	not typically visible	not typically visible	not typically visible
Spruce beetle	not typically visible	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window	not typically visible	not typically visible	not typically visible
Rapid ohia death	main window	main window	main window	main window	main window	main window	main window	main window	main window	main window	main window	main window
Goldspotted borer	not typically visible	not typically visible	not typically visible	not typically visible	main window	main window	main window	main window	main window	not typically visible	not typically visible	not typically visible

An adult spotted lanternfly resting on a wooden rail, showing spotted grey forewings — An adult spotted lanternfly on a wooden rail in southeastern Pennsylvania in early October, which is peak adult season. At rest the wings are grey with black spots; the scarlet hindwing only shows when it jumps. “Adult Lycorma delicatula” by Walthery, CC BY-SA 4.0

The live layer

What iNaturalist can and cannot see

Every state page on this site carries a live read of iNaturalist: research grade records in that state in the last twelve months, which answers the narrow question “has anybody seen it here lately”. That dataset is a record of where people looked, holding a phone. It is not a survey, it is not a range map, and a zero means nobody photographed it rather than that it is not there.

The table below shows it. Read down the record counts and the split is stark: the agents you can photograph on a leaf or a trunk have thousands to tens of thousands of records, and the ones that live under bark or need a culture plate have tens, nationally, across the entire history of the platform. That gap measures visibility. It measures nothing at all about damage.

Research grade iNaturalist records in the United States, whole platform history. The gap between the top group and the bottom group is not a measure of how much damage each one does.
Agent	US records	Why
Spotted lanternfly	91,063	Sits on a leaf, a needle or a trunk where anybody can photograph it.
Spongy moth	28,732	Sits on a leaf, a needle or a trunk where anybody can photograph it.
Beech leaf disease	8,003	Sits on a leaf, a needle or a trunk where anybody can photograph it.
Hemlock woolly adelgid	7,880	Sits on a leaf, a needle or a trunk where anybody can photograph it.
Emerald ash borer	4,362	Sits on a leaf, a needle or a trunk where anybody can photograph it.
Beech bark disease	803	Lives under bark or high in the crown, where a phone camera cannot reach it.
Sudden oak death	245	Diagnosed in a laboratory, not from a photograph.
Southern pine beetle	92	Lives under bark or high in the crown, where a phone camera cannot reach it.
Spruce beetle	63	Lives under bark or high in the crown, where a phone camera cannot reach it.
Asian longhorned beetle	45	Lives under bark or high in the crown, where a phone camera cannot reach it.
Laurel wilt	33	Diagnosed in a laboratory, not from a photograph.
Mountain pine beetle	31	Lives under bark or high in the crown, where a phone camera cannot reach it.
Goldspotted oak borer	31	Lives under bark or high in the crown, where a phone camera cannot reach it.
Oak wilt	30	Diagnosed in a laboratory, not from a photograph.
Rapid ohia death	2	Diagnosed in a laboratory, not from a photograph.
Dutch elm disease	1	Diagnosed in a laboratory, not from a photograph.
Thousand cankers disease	0	Diagnosed in a laboratory, not from a photograph.

Counts read from the iNaturalist API on 2026-08-29, research grade only, place United States. 5 of the 17 agents tracked here get a live panel and a monthly curve; the other 12 get their number published here and no curve anywhere, because there is no curve in thirty records.

By state

Every state, and what its own agency documents

Each page is built on that state’s Forest Health Highlights report, the annual document every state forestry agency publishes in cooperation with USDA Forest Service Forest Health Protection. It is the only source that answers this question uniformly for all fifty states, and hardly anybody outside forestry has heard of it.

Northeast

Maine (Ash borer) · New Hampshire (Ash borer) · Vermont (Ash borer) · Massachusetts (Beech leaf) · Connecticut (Beech leaf) · Rhode Island (Beech leaf) · New York (Spongy moth) · New Jersey (Beech leaf) · Pennsylvania (Lanternfly)

Southeast

Delaware (Ash borer) · Maryland (Beech leaf) · Virginia (Pine beetle) · West Virginia (Spongy moth) · North Carolina (Ash borer) · South Carolina (Pine beetle) · Georgia (Pine beetle) · Florida (Pine beetle) · Kentucky (Ash borer) · Tennessee (Ash borer) · Alabama (Pine beetle) · Mississippi (Pine beetle) · Arkansas (Ash borer) · Louisiana (Pine beetle)

Midwest

Ohio (Beech leaf) · Michigan (Oak wilt) · Indiana (Oak wilt) · Illinois (Oak wilt) · Wisconsin (Ash borer) · Minnesota (Ash borer) · Iowa (Ash borer) · Missouri (Ash borer) · Kansas (Ash borer) · Nebraska (Ash borer) · South Dakota (Ash borer) · North Dakota (Ash borer)

Rockies

Colorado (Mountain pine beetle) · Wyoming (Mountain pine beetle) · Montana (Mountain pine beetle) · Idaho (Mountain pine beetle) · Utah (Spruce beetle) · Nevada (Mountain pine beetle)

Southwest

Arizona (Mountain pine beetle) · New Mexico (Spruce beetle) · Texas (Oak wilt) · Oklahoma (Pine beetle)

West

California (Sudden oak death) · Oregon (Sudden oak death) · Washington (Mountain pine beetle) · Alaska (Spruce beetle) · Hawaii (Rapid ohia death)

Three findings from reading all fifty

The ash story has an end date in some states. Wisconsin recorded its first emerald ash borer county in 2008 and its seventy second and last in 2024. Iowa has it in all ninety nine counties. Pennsylvania has hemlock woolly adelgid, beech leaf disease and emerald ash borer in all sixty seven of its counties. There is nowhere left in those states to move it to.
Negative findings are published and nobody surfaces them. New Hampshire and Connecticut tested suspect samples and confirmed no oak wilt. Montana states outright that emerald ash borer has not been detected there, and Wyoming that it has not been positively confirmed. Kansas says it remains free of thousand cankers disease. Those are answers to real searches.
Half the country is a different subject. The eastern invasive complex is not what kills trees in Nevada, New Mexico or Alaska. Those are bark beetle and drought states, and their pages say so instead of pretending an ash borer map applies.

Close view of grey beech bark speckled with irregular white waxy dots — Beech bark disease at Pictured Rocks National Lakeshore in Michigan, photographed by the National Park Service. The white wax is the scale insect. The fungus that actually kills the tree comes in through the wounds it leaves. “The bark of the beech tree showing signs of beech bark disease.” — National Park Service — Public domain

What to do

You have a dying tree

You have a dying tree. Here is where to go.

Whether to treat a tree or take it down is a decision for somebody standing under it with a credential and a licence. These are the three doors.

Find a certified arboristA diagnosis on a specific tree, and any decision about what to do with it, belongs to somebody standing under it with a credential. That is not us. International Society of Arboriculture keeps the directory.
Your state forest health programmeThe your state forest health programme is the body that documents what is actually here, and its annual report is what this page is built from.
Report a suspected pestAPHIS keeps the current contact for every state plant health director and state plant regulatory official. For a regulated pest, that call is the one that matters.

The one thing you can actually do

Almost every agent on this page reached almost every place it is by riding in a piece of wood somebody put in a car. USDA APHIS says it in three words on both its emerald ash borer page and its spongy moth page:

Buy local firewood and burn it on site. Do not move firewood.

USDA APHIS, Spongy Moth

APHIS links dontmovefirewood.org from its own pest pages, so that is where this page points too. The campaign is run by The Nature Conservancy and its text is copyrighted, so nothing on this site quotes it; the wording above is APHIS’s own and is in the public domain.

Split firewood logs with the bark peeled back to show winding beetle galleries in the wood beneath — Emerald ash borer found in wood intercepted at a California agricultural inspection station. This is the whole argument for the firewood rule in one photograph: the beetle was in the wood, and the wood was in a vehicle. “Emerald Ash Borer in firewood (5815090311)” — USDA Forest Service Pacific Southwest Region 5 — Public domain

Coverage

Coverage, and claims checked against the record

Beyond the fifty state pages

The District of Columbia, Puerto Rico, Guam and the other territories. The pages are organised by the fifty states. APHIS lists spotted lanternfly and spongy moth in the District of Columbia, and its pages are the source for the District and for the territories.
Any pest not in the tracked list. Fifty state forest health reports name several hundred damage agents between them, including white pine needle disease, winter moth, jack pine budworm, fir engraver, balsam woolly adelgid and western spruce budworm. The seventeen agents tracked here are the ones people search for by name plus the ones a state or federal quarantine attaches to. A state page names its report, which covers the rest.
Any treatment, product or removal decision. Treatment and removal are an arborist's call on a specific tree, and several of the materials involved are restricted use, so every page routes to a certified arborist and the state forest health programme rather than carrying a product or a verdict.

Claims checked against the record

That emerald ash borer is "the largest tree mortality event in modern North America". No federal source states it in those words, and it is contestable against chestnut blight, which removed an entire canopy species. What APHIS does state, and what these pages carry, is "the death and decline of tens of millions of ash trees in North America".
A federal emerald ash borer quarantine map. There has not been one since January 14, 2021. The current federal picture is the repeal, and the state pages carry the state orders that remain.
APHIS county level infestation polygons for emerald ash borer. The APHIS interactive map is served under the MRP Map and Data Disclaimer, which restricts the underlying data to "restricted government purposes only" and calls it "the sole property of MRPBS, APHIS or AMS". So these pages carry the count APHIS states in prose and link its map.
Verbatim quotation from dontmovefirewood.org. The campaign is run by The Nature Conservancy and its footer reads "All rights reserved", which is not a reuse grant for an ad supported site. It is linked, as APHIS links it, and the verbatim firewood wording comes from APHIS.
A per state oak wilt, laurel wilt or thousand cankers activity curve from iNaturalist. Nationally, across the whole history of the platform, those three have 30, 33 and 0 research grade US records. There is no curve there, only noise. The national numbers are published instead, as evidence of what the dataset cannot see.
That hemlock woolly adelgid is present in Alaska. iNaturalist carries four research grade Alaska records of Adelges tsugae. Four records is not a detection, no Alaska agency documents it, and the state's own forest health programme is about spruce beetle. The number is in the snapshot; the claim is not on the page.
Any state level pest presence taken from an iNaturalist count. These pages rest on the distinction between "somebody photographed it here" and "an agency documented it here". Presence comes from the agencies. iNaturalist answers a narrower question and is labelled as answering it.

Tree pest questions

Is there still a federal emerald ash borer quarantine?

No. USDA APHIS states it on its own current emerald ash borer page: "APHIS removed its domestic EAB quarantine regulations in 2020. The final rule was effective January 14, 2021." The final rule is 85 FR 81085. This is the single most common wrong fact about tree pests in America, and almost every consumer article about ash trees still shows a federal quarantine map that has not existed for five years. What APHIS does still say is that it has "detected EAB infestations in 38 States and the District of Columbia".

Which tree pests ARE still federally quarantined?

Three, and none of them is the one people expect. Asian longhorned beetle under 7 CFR 301.51 in Massachusetts, New York, Ohio and South Carolina. Spongy moth under 7 CFR part 301 across twenty states and the District of Columbia, a boundary that was last amended on April 15, 2026. Sudden oak death under 7 CFR 301.92 in sixteen California counties and one Oregon county. Spotted lanternfly, despite being the one everybody has heard of, has no federal quarantine at all; its quarantines are state ones and they are redrawn most years.

Why are all the ash trees dying?

Emerald ash borer, a half inch metallic green beetle from Asia first detected in North America in southeast Michigan in 2002. The larvae feed under the bark and cut the tree's plumbing, and USDA APHIS describes it as "responsible for the death and decline of tens of millions of ash trees in North America". Wisconsin's own report captures the arc better than any summary: the first county detection there was in 2008 and the seventy second and final county was recorded in 2024.

What is killing my oak?

It depends entirely on where you are, which is why this site has a page per state. In the Midwest and Texas the usual answer is oak wilt, a fungus that plugs the tree's water vessels and can take a red oak from green to bare in a few weeks in midsummer. In coastal California and southwestern Oregon it is sudden oak death. In southern California it is the goldspotted oak borer. Across the East a defoliated oak in June is usually spongy moth, and usually survivable. Only a laboratory can separate several of these.

When would I actually notice each of these?

That is what the calendar on this page is for, and the answers are less obvious than people expect. Hemlock woolly adelgid is easiest to find in the depth of winter, because the white egg sacs stand out on a bare branch and the insect is not moving. Emerald ash borer signs read best with the leaves off, when the blonded bark left by woodpeckers is visible from the road. Beech leaf disease shows in late spring on newly expanded leaves, from underneath, looking up.

Does iNaturalist tell you where these pests are?

It tells you where people photographed them, which is a different and narrower thing. It works well for the five agents that sit somewhere a phone camera can reach: spotted lanternfly, spongy moth, beech leaf disease, hemlock woolly adelgid and emerald ash borer, which have thousands to tens of thousands of US records each. It is effectively blind to everything else. Sudden oak death has killed millions of trees and has a few hundred research grade US records in the entire history of the platform. Presence on this site comes from the state agencies; iNaturalist answers only "has anybody seen it here lately".

What can an ordinary person actually do?

One thing, and every federal agency says the same thing. USDA APHIS puts it in seven words on its spongy moth page: "Buy local firewood and burn it on site. Do not move firewood." Long distance firewood movement is how most of these organisms reached most of the places they are. The goldspotted oak borer is thought to have arrived in San Diego County in oak firewood from Arizona, and it is now killing California oaks.

Who decides whether to treat or remove a tree?

A certified arborist standing under the tree. Several of these diseases can only be confirmed in a laboratory, and several of the materials used against these organisms are restricted use and need a licensed applicator. What this page publishes is what is documented in your state, when it shows itself, and the three places to go: a certified arborist, your state forest health programme, and the federal reporting route for a regulated pest.

Fall foliage by stateA dying tree is not autumn colour. Telling them apart starts with knowing when the real colour arrives.Ant season by stateCarpenter ants move into wood that is already decaying. Finding them is a symptom of the tree, not the cause.Termite swarm seasonThe other insect people find in dead wood, and the one that actually threatens the building.

A certified arborist working in the crown of a large elm tree that is being taken down — A certified arborist removing an infected elm in Saint Paul, Minnesota. This is the end of the road for Dutch elm disease and it is also the point of this whole page: the decision about a specific tree belongs to somebody standing under it with a credential. “Dutch Elm-3” — Susan G. Lesch — Public domain

Regulatory status and pest biology on this page are quoted verbatim from USDA APHIS and the National Park Service, which are works of the United States Government and in the public domain. Per state findings come from each state’s Forest Health Highlights report, hosted by the USDA Forest Service. Cooperative extension material is copyrighted and is never quoted here; where an extension or nonprofit source established a fact, it is restated in our words and the institution is named. iNaturalist counts are a record of where people looked. MyWild states no diagnosis, recommends no treatment and names no product.