Unfortunately, there are a number of potentially serious diseases that can infect trees across Virginia.
Some cause little more than seasonal leaf damage, but others quietly attack roots, bark, or internal tissues until a tree begins to decline. And because different diseases can produce similar symptoms, knowing what you’re looking at isn’t always straightforward.
But recognizing trouble early can give you more options for protecting your trees. We’ll try to help you do exactly that by identifying some of the common tree diseases in Virginia, outlining the warning signs to watch for, and highlighting the treatments that may help.
Common Tree Diseases in Northern Virginia
Northern Virginia’s oaks (Quercus spp.), maples (Acer spp.), dogwoods (Cornus spp.), beeches (Fagus spp.), and other landscape trees face diseases caused by fungi, bacteria, water molds, and even microscopic worms called nematodes.
We’ve organized the following diseases by the parts of the tree they primarily affect. This isn’t an exhaustive list, but it covers many important threats homeowners should recognize.
Vascular & Wilt Diseases
A tree’s vascular system moves water and nutrients between its roots and canopy. Diseases that interfere with this system can cause wilting, leaf scorch, premature leaf drop, and branch dieback.
Some of the most important vascular diseases affecting Virginia trees include the following.
Bacterial Leaf Scorch (Xylella fastidiosa)
Bacterial leaf scorch is a serious, chronic disease of Northern Virginia’s oaks, especially members of the red oak group, such as pin oaks (Quercus palustris) and northern red oaks (Q. rubra). It also affects elms (Ulmus spp.), sycamores (Platanus spp.), and other hardwoods.
The bacteria are spread by sap-feeding insects such as leafhoppers, sharpshooters, and spittlebugs. The bacteria interfere with water movement, causing leaf margins to turn brown while surrounding tissue may remain yellow or green, typically from late summer into fall.
Symptoms of bacterial leaf scorch may not appear for a year or two after infection, but many infected trees will decline and die within 5 to 7 years.
Verticillium Wilt (Verticillium spp.)
Verticillium wilt is a soilborne fungal disease that affects maples, redbuds (Cercis spp.), and numerous other hardwoods. The fungi enter through roots and spread into the water-conducting tissues, causing leaves to wilt, scorch, or drop prematurely.
Symptoms sometimes develop on just one branch or a few branches. The fungi can also travel in infested soil, wood, and contaminated tools, so wood from infected trees shouldn’t be chipped for mulch.
Dutch Elm Disease (Ophiostoma spp.)
Dutch elm disease primarily affects elm trees and, rarely, some of their close relatives, such as zelkova trees (Zelkova spp.). It spreads through elm bark beetles and root connections between neighboring elms.
Wilting and browning leaves may first appear on individual branches before the disease spreads through the canopy. Without effective management, susceptible elms can decline rapidly.
Oak Wilt (Bretziella fagacearum)
Oak wilt is a serious fungal disease that disrupts water transport in oak trees.
Infected red oaks may develop browning leaves, premature leaf drop, and rapid canopy decline. The fungus is carried by sap-feeding beetles to fresh wounds, especially in spring, and can move underground through connected roots between neighboring oaks.
In Virginia, oak wilt has been documented mainly in the western part of the state. Because several other conditions can resemble oak wilt, suspected cases may require laboratory diagnosis.
Canker & Bark Diseases
Canker diseases damage localized areas of a tree’s bark and underlying tissue, sometimes creating sunken lesions, cracks, or patches of dead bark. When cankers expand around branches or stems, they can interfere with water and nutrient movement and cause dieback.
Biscogniauxia (Hypoxylon) Canker (Biscogniauxia spp.)
Often associated with drought-stressed oaks and other hardwoods, biscogniauxia canker may become apparent when sections of bark peel away, exposing the dark fungal tissue beneath. Affected trees may also show thinning foliage and branch dieback.
The fungus often lives harmlessly inside healthy oaks and becomes damaging only after drought or other stress weakens them. Once the fungal mats appear, decline can be rapid, so keeping trees healthy before trouble starts is an important part of managing risk.
Phytophthora Bleeding Cankers (Phytophthora spp.)
Certain Phytophthora species can cause cankers on trunks and lower stems, particularly when trees grow in excessively wet conditions. Beeches (Fagus spp.), maples, and oaks are especially susceptible.
Splashing rain can carry spores to the lower trunk, and bark wounds from lawn equipment give the pathogen an entry point. Dark, discolored bark and fluid seeping from affected areas may be visible, although bleeding alone doesn’t confirm the disease.
Seiridium Canker (Seiridium spp.)
Leyland cypress (× Cuprocyparis leylandii), commonly planted for privacy screening in Northern Virginia, is particularly vulnerable to seiridium canker. The fungus spreads mainly through rain-splashed spores during wet weather.
The disease produces dark, cracked lesions on stems and branches, sometimes accompanied by resin. Individual branches may turn reddish-brown and die, leaving noticeable gaps in an otherwise green screen. Drought stress can make the damage more severe.
Botryosphaeria Canker (Botryosphaeria spp. and related fungi)
Botryosphaeria canker affects many ornamental trees and shrubs, especially those weakened by drought, injury, or poor growing conditions. It also affects Leyland cypress, where it’s easily confused with seiridium canker.
Symptoms include sunken or discolored bark, wilting leaves, and dying branches. Because several fungi can produce similar symptoms, identifying the underlying problem helps determine the appropriate management approach.
Thousand Cankers Disease (Geosmithia morbida)
Thousand cankers disease affects black walnut (Juglans nigra) trees and involves a fungus carried by the walnut twig beetle. As beetles tunnel beneath the bark, numerous small cankers may form and eventually interfere with water and nutrient transport.
Although the disease has been documented in Northern Virginia, subsequent surveys found that it was far less widespread and damaging than originally feared. In fact, Virginia lifted its quarantine in 2024 after determining that the disease posed little threat to healthy walnut trees.
Root & Belowground Diseases
Root diseases are particularly concerning because the damage often develops out of sight. As roots deteriorate, trees may struggle to absorb water and nutrients, and severe decay can weaken their anchorage.
Two important examples include the following.
Phytophthora Root Rot (Phytophthora spp.)
Phytophthora root rot is caused by water molds that thrive in wet, poorly drained soils. Dogwoods, beeches, maples, white pines (Pinus strobus), and azaleas (Rhododendron spp.) are among its many hosts.
Symptoms often resemble drought stress and may include yellowing leaves, reduced growth, and gradual canopy thinning. The pathogen moves in splashing water and runoff and often arrives on infected nursery plants. Improving drainage and addressing root-zone conditions are important parts of managing this disease.
Armillaria Root Rot (Armillaria spp.)
Armillaria root rot affects numerous hardwoods and conifers, sometimes causing extensive root and lower-trunk decay.
Signs may include thinning foliage, branch dieback, white fungal growth beneath the bark, and dark, rootlike structures called rhizomorphs. Clusters of honey-colored mushrooms sometimes appear near the base in autumn.
Advanced infections can weaken structural roots, making an assessment especially important when the tree stands near a home, driveway, or frequently used outdoor space.
Twig & Foliar Diseases
Leaf and twig diseases often produce the most visible symptoms, from spotted or distorted leaves to premature defoliation. Some are largely cosmetic, while others can cause lasting damage or progressive decline.
Beech Leaf Disease (Litylenchus crenatae subsp. mccannii)
Beech leaf disease is associated with a microscopic nematode rather than a fungus or bacterium. It affects American beeches (Fagus grandifolia) and European beeches (F. sylvatica) and has become an important concern in the Mid-Atlantic.
To identify beech leaf disease, look for dark bands between leaf veins, thickened or curled leaves, and thinning canopies. Repeated damage can weaken trees, particularly younger beeches. Severely affected trees may decline over several years, with some dying within 5 to 7 years.
Anthracnose (Several Fungal Pathogens)
Anthracnose refers to a group of fungal diseases affecting dogwoods, sycamores, oaks, maples, and other hardwoods. These fungi spread through rain, dew, and insects.
Symptoms commonly include irregular brown leaf spots, distorted foliage, and premature leaf drop. Many anthracnose infections cause limited lasting damage, but dogwood anthracnose, caused by Discula destructiva, can also infect twigs and branches and seriously threaten flowering dogwoods (Cornus florida).
Powdery Mildew (Various Fungi)
Powdery mildew creates a recognizable white or gray powdery coating on leaves and young shoots. Dogwoods, crape myrtles (Lagerstroemia indica), and many ornamental plants are susceptible. On flowering dogwoods, it has overtaken anthracnose as the most serious disease.
Although infections are often more unsightly than dangerous, severe cases can distort foliage and reduce growth.
Leaf Spot Diseases (Cercospora, Tubakia, and Other Fungi)
Leaf spot diseases produce brown, tan, or dark lesions that vary in shape and size depending on the pathogen and host tree. Many of these fungi spread through wind and splashing rain, so outbreaks tend to follow wet growing seasons.
Tubakia leaf spot is especially common on oaks in the red oak group. It typically appears in mid- to late summer as reddish-brown spots or blotches, often along leaf veins. Heavy infections can cause early leaf drop, but established trees usually recover without lasting damage.
Cedar-Apple & Related Rust Diseases (Gymnosporangium spp.)
Rust diseases affect junipers (Juniperus spp.) and susceptible members of the rose family, including crabapples (Malus spp.) and hawthorns (Crataegus spp.).
Depending on the host, symptoms may include yellow-orange leaf spots, swollen twigs, or conspicuous orange fungal growths on junipers. These fungi require different host plants to complete their life cycles, making nearby plant selection relevant to disease management.
Fire Blight (Erwinia amylovora)
Fire blight is a bacterial disease affecting pears (Pyrus spp.), apples, crabapples, hawthorns, and related plants. Insects, rain, and wind spread the bacteria in spring, and pruning during the growing season can spread it further.
Infected flowers and young shoots wilt and darken, sometimes developing the distinctive hooked appearance known as a shepherd’s crook. Severe infections can spread into branches and produce cankers, making timely diagnosis and appropriate pruning especially important.
Wood & Structural Decay Diseases
Some fungi gradually break down the wood inside living trees. Unlike leaf diseases, internal decay may remain hidden until fungal fruiting bodies appear or structural weakness becomes apparent.
A tree can even maintain a relatively full canopy while significant decay develops within its trunk or roots.
Ganoderma Butt & Root Rot (Ganoderma spp.)
Ganoderma fungi can decay roots and lower-trunk wood in numerous hardwood species.
Shelf-like fungal structures, called conks, may appear near the tree’s base. Because advanced decay can weaken structural roots and trunk wood, these signs warrant professional evaluation.
Inonotus & Related Heart Rots (Inonotus and Pseudoinonotus spp.)
These fungi cause internal wood decay in oaks and other hardwoods, sometimes entering through wounds or damaged branches.
Fungal fruiting bodies may develop on trunks or major limbs, but decay can progress without obvious external symptoms. The location and extent of damage determine how seriously the tree’s structural strength is affected.
Laetiporus Brown Rot (Laetiporus spp.)
Commonly called chicken of the woods, Laetiporus fungi produce distinctive orange and yellow shelf-like growths on trunks, branches, or near the base of trees.
They cause brown rot that can significantly weaken affected wood. Even if the canopy looks healthy, the presence of these fungi deserves attention when the tree could fall or shed branches onto people or property.
Kretzschmaria Root & Butt Decay (Kretzschmaria deusta)
Also known as brittle cinder fungus, Kretzschmaria deusta affects the roots and lower trunks of susceptible hardwoods, including beeches and maples. Wounds at the base of the trunk from mowers and string trimmers are common entry points.
Its fruiting structures may begin as gray patches before becoming hard, black crusts. The fungus can cause serious internal decay without dramatic canopy symptoms.
Take Photos of Mushrooms & Conks
Mushrooms growing from a trunk, major branch, or around a tree’s base can provide important clues about hidden decay. Some appear only briefly, so take clear photographs before they disappear.
Include close-ups and wider views showing where the growth occurs. These photos can help your arborist evaluate the problem, although identifying a fungus doesn’t automatically reveal how much sound wood remains.
How Are Tree Diseases Treated?
There’s no single treatment that works for every tree disease. The best approach depends on the pathogen, tree species, severity of infection, and overall growing conditions.
Some treatments help suppress disease or protect new growth. Others focus on removing infected tissue, improving tree health, or managing structural risks.
Fungicides & Other Targeted Disease Treatments
Certain fungal diseases can be managed with appropriately timed fungicide applications. Depending on the diagnosis, treatments may be applied to foliage, bark, soil, or through trunk injections.
Phosphite-based products may also be useful against certain Phytophthora diseases and in specific disease-management programs. However, fungicides and phosphites are not universal cures, and established internal decay cannot be reversed by spraying a tree.
Antibiotic Treatments
Some bacterial diseases, including bacterial leaf scorch, may be managed with specialized antibiotic treatments administered by qualified professionals.
These treatments may temporarily suppress symptoms or slow decline, but they generally do not eliminate the underlying infection. Repeated treatment and monitoring may be necessary.
Pruning & Sanitation
Removing infected branches can help manage certain canker diseases, fire blight, and other problems when the infection is limited to accessible tissues.
The timing and location of cuts matter. Improper pruning can create additional wounds, remove too much healthy foliage, or contribute to disease spread. Severely affected material may also require appropriate disposal.
Soil & Root-Zone Care
Healthy roots are essential to a tree’s ability to tolerate disease. When compacted soil, poor drainage, or buried root collars contribute to decline, correcting those conditions may improve the tree’s prospects.
Depending on the site, care may include soil testing, root collar excavation, aeration, vertical mulching, or drainage improvements. These practices support root function but do not directly cure every root disease.
Biostimulants & Preventive Plant Health Care
Biostimulants and other soil-support treatments may be appropriate for some trees experiencing environmental stress or poor root-zone conditions. Their benefits depend on the product and application method used, as well as the underlying problem.
A broader plant health care program can combine inspections, monitoring, targeted treatments, and improvements to growing conditions. Rather than waiting for severe symptoms, this approach helps identify developing problems and manage them before damage becomes extensive.
Disease Diagnosis Doesn’t Always Mean Removal
Some tree diseases can be managed through targeted treatments, pruning, or improvements to growing conditions. Others may require ongoing monitoring rather than immediate intervention.
The best course of action depends on the diagnosis, the extent of damage, and whether the tree remains structurally sound.
Structural Support & Tree Removal
When disease has weakened major branches, roots, or trunk wood, treatment alone may not address the safety concern.
In selected cases, cabling or bracing can help support structurally compromised branches. However, these systems cannot restore decayed wood or make every tree safe to retain.
If decay or decline has progressed too far, removal may be the most appropriate option. An RTEC Treecare arborist can evaluate the tree’s condition, surrounding targets, and available alternatives before recommending that step.
Tree Diseases in Virginia: Frequently Asked Questions
Tree problems can be confusing, especially when drought, pests, and disease all leave similar clues. Here are answers to some common homeowner questions.
What are the most common tree diseases in Northern Virginia?
Common tree diseases in Northern Virginia include bacterial leaf scorch, anthracnose, powdery mildew, leaf spot diseases, verticillium wilt, Phytophthora root rot, and various canker and wood decay diseases. Beech leaf disease is a newer but growing concern in the region.
How can I tell whether my tree has a disease?
Watch for unusual leaf discoloration, wilting, premature leaf drop, branch dieback, bark lesions, fungal growth, or progressive canopy thinning. These symptoms can also result from environmental stress or insects, so diagnosis is important before treatment.
Can a diseased tree recover?
Sometimes. Many leaf diseases cause temporary damage, while other infections can be managed to slow decline. Recovery depends on the disease, its progression, the tree’s overall health, and whether effective management options are available.
Can tree diseases spread to neighboring trees?
Yes, some pathogens spread through insects, airborne spores, rain splash, infected plant material, or connected roots. Others persist in soil. However, not every disease is highly contagious, and susceptibility varies among tree species.
Should I spray fungicide on a tree with brown leaves?
Not before identifying the cause. Brown leaves can result from drought, root problems, insects, bacterial infections, or fungal diseases. Fungicides only help with certain diseases and often work best when applied at specific times.
Does a mushroom growing on my tree mean it needs to be removed?
Not necessarily. Some mushrooms indicate decaying wood, but the structural implications depend on the fungus, its location, and the extent of decay. An arborist can evaluate whether the tree can be retained safely.
When should I call an arborist about a potentially diseased tree?
Arrange an evaluation when symptoms worsen, recur over multiple seasons, affect major branches, or involve the trunk or roots. Sudden wilting, extensive dieback, or signs of structural instability deserve especially prompt attention.
Protect Your Virginia Trees with Professional Disease Care
A diseased tree doesn’t always need to come down. But the earlier you understand what’s causing the problem, the more options you may have for managing it.
Whether you’re seeing unusual leaf spots, declining branches, or signs of root decay, RTEC Treecare’s ISA-certified arborists can help you understand what’s happening and what to do next.
Contact RTEC Treecare to schedule an evaluation and take the next step toward protecting your trees.
Sources & References
- Virginia Cooperative Extension – “Bacterial Leaf Scorch of Landscape Trees”
Virginia Tech extension publication (SPES-568NP) identifying red oaks as the most commonly affected hosts in Virginia, with elms and sycamores also common; describes late-summer marginal scorch with a yellow band, symptoms spreading branch by branch over years, and antibiotic injections that slow the disease but do not cure it.
https://pubs.ext.vt.edu/3001/3001-1433.html - University of Delaware Cooperative Extension – “Bacterial Leaf Scorch”
Mid-Atlantic extension fact sheet (revised 2025) explaining that Xylella fastidiosa is spread by leafhoppers, sharpshooters, and spittlebugs; that symptoms may take a year or two to appear; that northern red oak and pin oak have been especially affected in Mid-Atlantic residential landscapes since the early 1990s; and that infected trees can die within 5 to 7 years.
https://udel.edu/content/dam/udelImages/canr/pdfs/extension/factsheets/Bacterial-Leaf-Scorch.pdf - Virginia Cooperative Extension – “Verticillium Wilt of Shade Trees”
Virginia Tech extension publication (450-619/SPES-571NP) identifying maples and redbuds among susceptible hosts and explaining that the soilborne fungi enter through roots, causing wilting, scorched or browning leaves, defoliation, and vascular streaking, sometimes on only one branch or a few branches; also warns that the fungi move in infested soil, wood, and tools and that infected wood shouldn’t be chipped for mulch.
https://pubs.ext.vt.edu/450/450-619.html - NC State Extension – “Dutch Elm Disease”
Extension fact sheet explaining that elm bark beetles and root grafts spread the fungus, describing wilting and browning on individual branches (flagging), and noting that infected elms can die within a year.
https://content.ces.ncsu.edu/dutch-elm-disease-1 - Virginia Department of Forestry – “Beech Leaf Disease”
State forestry agency page attributing beech leaf disease to the nematode Litylenchus crenatae subsp. mccannii, noting that it may spread through insects, birds, rain splash, and wind, describing banding between leaf veins and curled, thickened leaves, noting that infected trees can die within 2 to 10 years, and documenting the first Virginia detection in Prince William County in 2021.
https://dof.virginia.gov/forest-management-health/forest-health/insects-and-diseases/beech-leaf-disease - USDA Forest Service – “Virginia Forest Health Highlights 2024”
Federal–state forest health report tracking beech leaf disease from Prince William County (2021) into Fairfax (2022), Loudoun and Stafford (2023), and Clarke and New Kent (2024) counties; supports the disease’s status as a growing Northern Virginia concern.
https://www.fs.usda.gov/foresthealth/docs/fhh/VA_FHH_2024.pdf - University of Maryland Extension – “Beech Leaf Disease”
Mid-Atlantic extension fact sheet confirming that both American and European beeches are susceptible and that younger understory beeches are especially vulnerable.
https://extension.umd.edu/resource/beech-leaf-disease-0 - Don’t Move Firewood (The Nature Conservancy) – “Oak Wilt”
National forest-pest outreach program describing oak wilt’s range as extending through western Virginia, identifying red oaks as the most vulnerable hosts, and explaining spread by sap-feeding beetles to fresh wounds (especially in spring) and through root grafts between oaks.
https://www.dontmovefirewood.org/pest_pathogen/oak-wilt - Virginia Department of Agriculture and Consumer Services – “Diseases of Regulatory Concern”
State regulatory page reporting that 2021–2022 surveys could not detect thousand cankers disease at many previously confirmed Virginia sites and that the state’s quarantine was repealed in August 2024.
https://www.vdacs.virginia.gov/plant-industry-services-diseases-of-regulatory-concern.shtml - NC State Extension – “Biscogniauxia (Hypoxylon) Canker”
Extension fact sheet explaining that the fungus lives harmlessly in healthy oaks until drought or other stress triggers disease, that fungal mats push bark off to expose dark tissue, that oaks often die within weeks once fungal mats appear, and that maintaining tree vigor is the primary management strategy.
https://content.ces.ncsu.edu/biscogniauxia-hypoxylon-canker - UMass Extension – “Phytophthora Bleeding Canker”
Landscape fact sheet noting that Phytophthora thrives in wet soils, that splashing rain and bark wounds from lawn equipment help it reach and infect the lower trunk, that bleeding cankers alone don’t confirm the disease, and that phosphite applications have proven effective against Phytophthora.
https://www.umass.edu/agriculture-food-environment/landscape/fact-sheets/phytophthora-bleeding-canker - University of Maryland Extension – “Seiridium and Botryosphaeria Canker of Leyland Cypress”
Regional extension guidance on Leyland cypress cankers, including scattered branches that yellow and turn reddish-brown, resin near cankers, rain-spread spores in wet spring weather, how Botryosphaeria (little resin, fruiting bodies under the bark) differs from Seiridium, and drought stress as a key trigger for both diseases.
https://extension.umd.edu/resource/seiridium-and-botryosphaeria-canker-leyland-cypress - Penn State Extension – “Phytophthora Root Rot on Woody Ornamentals”
Extension article explaining that poorly drained or wet soils favor Phytophthora, listing hosts including dogwood, beech, maple, white pine, rhododendron, and azalea, describing spread through splashing water, runoff, and infected nursery plants, describing wilting and stunting symptoms, and emphasizing prevention because no chemicals cure an infected plant.
https://extension.psu.edu/phytophthora-root-rot-on-woody-ornamentals - Penn State Extension – “Armillaria Root Rot of Trees”
Extension article describing white fungal fans beneath the bark, dark rhizomorphs that can grow several feet through soil from stumps to nearby trees, honey-colored mushrooms at the tree base in autumn, and the greater vulnerability of trees stressed by drought or root injury.
https://extension.psu.edu/armillaria-root-rot-of-trees - University of Maryland Extension – “Dogwood Anthracnose”
Extension fact sheet explaining how dogwood anthracnose spreads by rain, dew, and insects and moves from leaves into twigs and limbs, causing dieback that can kill infected trees, and noting that powdery mildew has now become the most serious dogwood disease.
https://extension.umd.edu/resource/dogwood-anthracnose - University of Wisconsin–Madison Extension – “Tubakia (Actinopelte) Leaf Spot”
Extension article identifying red oak group species as most susceptible, describing dark brown to reddish-brown spots that often form along leaf veins in July and August, noting that spores spread by wind and rain splash, and explaining that the disease is usually cosmetic because it appears late in the season.
https://hort.extension.wisc.edu/articles/tubakia-actinopelte-leaf-spot/ - Penn State Extension – “Fire Blight in Ornamentals”
Extension article identifying Erwinia amylovora as the cause, listing pear, apple, crabapple, and hawthorn as hosts, and describing blackened blossoms and shoots, shepherd’s crook tips, sunken cankers, spread by insects, rain, and wind in spring, and dormant-season pruning well below cankers because growing-season pruning can spread the disease.
https://extension.psu.edu/fire-blight-in-ornamentals - UMass Extension – “Root and Butt Rot Caused by Kretzschmaria deusta”
Landscape fact sheet identifying beeches and maples as key hosts, describing gray fruiting bodies near the soil line that darken to black, noting that canopy symptoms can be minimal even as wood loses strength, and identifying mower and string-trimmer wounds as common entry points.
https://www.umass.edu/agriculture-food-environment/landscape/fact-sheets/root-butt-rot-caused-by-kretzschmaria-deusta - UMass Urban Tree Program – “Wood Decay Fungi on Living Trees”
University fact sheet covering Ganoderma and Laetiporus (chicken of the woods), describing the brown rot Laetiporus causes as leading to rapid strength loss, and treating conks on trunks as warning signs.
https://www.umass.edu/urbantree/factsheets/25wooddecayfungi.html
