Chapel Hill and Durham are known for their beautiful tree canopies, but they’re also home to a wide variety of tree pests and diseases. From destructive borers and sap-feeding insects to fungal pathogens and bacterial infections, tree health problems are common throughout central North Carolina.
Learning to identify the early signs of pest and disease problems is one of the best things homeowners can do to protect their trees. We’ll try to help in this regard by sharing some of the most common problems affecting local trees below, as well as the symptoms they cause and treatment options available.
Identifying Common Tree Pests and Diseases in Chapel Hill and Durham
Tree pests and diseases affect trees in different ways. Some tunnel beneath the bark and damage a tree’s vascular system, while others feed on leaves, sap, or tender new growth. Diseases can cause symptoms ranging from leaf discoloration and branch dieback to fungal growth and progressive canopy decline. The categories below cover some of the most common tree health problems that Chapel Hill and Durham homeowners may encounter.
Tree Borers
Tree borers tunnel beneath a tree’s bark, where they feed on the tissues responsible for transporting water and nutrients. Because much of the damage occurs out of sight, these pests can weaken or even kill trees before homeowners realize there’s a problem.
- Emerald Ash Borer: This destructive invasive insect attacks ash trees and can cause canopy thinning, bark splitting, and tree death if left untreated.
- Ambrosia Beetles: These tiny beetles are often identified by the distinctive “toothpick” strands of sawdust protruding from the bark of stressed trees.
- Dogwood Borer: This pest causes bark damage, swelling, and branch dieback in flowering dogwoods and other susceptible trees.
- Two-Lined Chestnut Borer: This boring insect commonly attacks stressed oak trees and causes browning leaves and progressive canopy decline.
- Pine Bark Beetles: These insects bore beneath the bark of pine trees and can cause rapid decline in weakened or drought-stressed specimens.
- Flatheaded Appletree Borer: This pest attacks a variety of hardwood trees and often leaves behind winding galleries beneath the bark.
Sap-Feeding Insects
Sap-feeding insects extract nutrients from leaves, stems, and branches, often reducing a tree’s vigor over time. Many of these pests also produce sticky honeydew or cause leaf discoloration that serves as an early warning sign of infestation.
- Aphids: These tiny insects feed on new growth and produce sticky honeydew that may attract ants and promote sooty mold growth.
- Scale Insects: These unusual pests often resemble small bumps or shells attached to bark, twigs, and leaves rather than living insects.
- Spider Mites: These tiny arachnids feed on foliage and may cause stippling, bronzing, and premature leaf drop during hot, dry weather.
- Lace Bugs: These sap-feeding insects cause leaves to develop a speckled or bleached appearance and are particularly common on ornamental trees and shrubs.
- Hemlock Woolly Adelgid: This invasive insect appears as white, cotton-like masses on eastern hemlock branches and can eventually kill untreated trees.
Leaf-Chewing Insects
Leaf-chewing insects feed directly on a tree’s foliage and can cause everything from minor cosmetic damage to severe defoliation. While healthy trees can often tolerate occasional feeding, repeated or widespread damage may leave trees vulnerable to additional stressors.
- Japanese Beetles: These metallic green beetles skeletonize leaves by consuming the tissue between the veins.
- Bagworms: These insects create protective bags from silk and plant material that hang from twigs and branches.
- Fall Webworms: These caterpillars build large silk webs around branch tips and feed on enclosed foliage during late summer and fall.
- Eastern Tent Caterpillars: These insects construct silken tents in branch crotches during spring and feed on newly emerging leaves.
- Sawflies: These caterpillar-like larvae feed in groups and can quickly defoliate susceptible trees.
- Walnut Caterpillars: These large, hairy caterpillars are capable of stripping walnut and hickory trees of their foliage.
- Spongy Moth Caterpillars: These voracious leaf feeders can cause significant defoliation of oaks and other hardwood species during severe outbreaks.
Common Tree Diseases
Not all tree health problems are caused by insects. Many fungal and bacterial diseases produce symptoms that closely resemble pest damage, including canopy thinning, leaf discoloration, branch dieback, and premature leaf drop.
- Anthracnose: This fungal disease causes irregular brown or black leaf blotches and is especially common during cool, wet spring weather.
- Powdery Mildew: This disease appears as a white, powder-like coating on leaves and young shoots of susceptible trees and ornamentals.
- Bacterial Leaf Scorch: This bacterial disease produces scorched-looking leaf margins that are often mistaken for drought stress or insect damage.
- Verticillium Wilt: This soilborne fungal disease causes wilting, yellowing foliage, and branch dieback that frequently affects only one section of the canopy.
- Needle Cast Diseases: These fungal diseases cause pine and spruce needles to discolor and drop prematurely.
- Leaf Spot Diseases: These diseases produce dark spots or lesions on leaves and may lead to premature leaf drop.
- Root Rot: This condition causes gradual canopy thinning, reduced vigor, and branch dieback that can resemble insect or drought damage.
- Dogwood Anthracnose: This fungal disease causes leaf spots, twig dieback, and cankers that may become fatal if severe.
- Cercospora Leaf Spot: This common disease affects crepe myrtles and causes reddish or brown leaf spots that can lead to premature defoliation.
- Beech Leaf Disease: This emerging disease causes dark banding between leaf veins and progressive canopy decline in affected beech trees.
Tree Pests and Diseases by Tree Species
Some pests and diseases strongly prefer specific tree species, making tree identification one of the most valuable tools for diagnosing problems. If you’ve noticed unusual symptoms on one of your landscape trees, reviewing the common issues associated with that species can help you narrow down the list of potential culprits.
Cypress & Arborvitae Tree Pests & Diseases
Leyland cypresses, arborvitaes, and other cypress relatives are popular privacy trees throughout Chapel Hill and Durham, but they can be particularly susceptible to pests and diseases when planted in stressful growing conditions or too closely together.
- Bagworms: These destructive pests frequently infest arborvitaes and cypress trees and can quickly strip foliage from entire branches.
- Seiridium Canker: This fungal disease causes branch dieback, resin flow, and progressive decline in Leyland cypress and related species.
- Cercospora Needle Blight: This disease causes the inner foliage of arborvitaes to turn brown and drop prematurely, often beginning near the lower branches.
- Spider Mites: These tiny arachnids may cause bronzing and thinning foliage during periods of hot, dry weather.
- Scale Insects: These sap-feeding insects can weaken trees and contribute to discoloration and reduced vigor.
- Phytophthora Root Rot: This serious root disease develops in poorly drained soils and can cause rapid decline or death in susceptible trees.
Cedar Tree Pests & Diseases
Eastern red cedars are hardy native trees that thrive throughout central North Carolina, but they aren’t immune to pest and disease problems. Several insects and fungal pathogens can affect their appearance, health, and long-term vigor.
- Bagworms: These insects construct protective bags from foliage and silk and can cause significant defoliation when populations are high.
- Cedar-Apple Rust: This fungal disease produces distinctive orange, gelatinous growths on cedar trees and requires both cedars and apple-family trees to complete its life cycle.
- Spider Mites: These tiny arachnids feed on foliage and may cause bronzing and discoloration during hot, dry weather.
- Scale Insects: These sap-feeding pests can weaken cedars and contribute to declining vigor over time.
- Root Rot: This condition can develop in poorly drained soils and may lead to canopy thinning and branch dieback.
Pine Tree Pests & Diseases
Pines are a defining feature of the North Carolina landscape, but they are susceptible to several insects and diseases that can cause rapid decline when left untreated.
- Pine Bark Beetles: These destructive insects can kill weakened or drought-stressed pine trees.
- Pine Tip Moths: These pests damage new growth and may cause shoot dieback.
- Needle Cast Diseases: These fungal diseases cause needles to discolor and drop prematurely.
- Sawflies: These caterpillar-like larvae feed on pine needles and can cause significant defoliation.
- Root Rot: This condition may weaken pine trees and contribute to instability and decline.
Oak Tree Pests & Diseases
Oak trees are among the most iconic trees in central North Carolina, but they’re susceptible to a variety of insects and diseases, particularly when stressed by drought, construction damage, or poor growing conditions.
- Two-Lined Chestnut Borer: This destructive boring insect frequently attacks stressed or declining oaks and causes canopy thinning and branch dieback.
- Spongy Moth Caterpillars: These voracious leaf feeders can cause widespread defoliation during severe outbreaks.
- Bacterial Leaf Scorch: This disease produces scorched-looking leaf margins and can contribute to long-term tree decline.
- Anthracnose: This fungal disease causes leaf spotting and premature leaf drop during cool, wet weather.
- Oak Leafrollers: These small caterpillars roll or tie leaves together while feeding on tender foliage.
Maple Tree Pests & Diseases
Maples are popular shade trees throughout Chapel Hill and Durham, but they can be affected by both sap-feeding insects and several common fungal diseases.
- Scale Insects: These sap-feeding pests commonly infest mature maples and may contribute to declining vigor.
- Aphids: These insects produce sticky honeydew and may cause leaf curling or distortion.
- Verticillium Wilt: This soilborne fungal disease causes wilting, yellowing foliage, and branch dieback.
- Anthracnose: This fungal disease causes irregular leaf blotches and premature leaf drop.
- Spider Mites: These tiny arachnids may cause stippling and bronzing during periods of hot, dry weather.
Dogwood Tree Pests & Diseases
Flowering dogwoods are beloved ornamental trees throughout North Carolina and are vulnerable to several significant pests and diseases.
- Dogwood Borer: This pest causes bark damage, swelling, and branch dieback in susceptible trees.
- Dogwood Anthracnose: This fungal disease can cause leaf spots, cankers, and progressive canopy decline.
- Powdery Mildew: This common fungal disease appears as a white coating on leaves and young shoots.
- Scale Insects: These insects may weaken trees and contribute to their overall decline.
Japanese Beetles: These metallic green beetles occasionally feed on dogwood foliage and flowers.
Crepe Myrtle Tree Pests & Diseases
Crepe myrtles are some of the most popular ornamental trees in central North Carolina and are particularly susceptible to a few well-known pests and diseases.
- Crepe Myrtle Bark Scale: This pest appears as white or gray waxy masses on trunks and branches and is often accompanied by black sooty mold.
- Aphids: These insects produce sticky honeydew that can coat leaves and promote mold growth.
- Powdery Mildew: This fungal disease appears as a white coating on leaves and flower buds.
- Cercospora Leaf Spot: This disease causes reddish-brown leaf spots and premature leaf drop.
- Spider Mites: These tiny pests may cause stippling and discoloration during hot, dry weather.
Cherry Tree Pests & Diseases
Both ornamental and fruiting cherry trees are susceptible to a variety of insect pests and fungal diseases.
- Eastern Tent Caterpillars: These caterpillars build silken tents during spring and can defoliate trees when populations are high.
- Japanese Beetles: These insects feed on cherry tree leaves and leave behind a characteristic skeletonized appearance.
- Peachtree Borers: These pests attack the lower trunk and root flare of susceptible trees.
- Black Knot: This fungal disease produces black, swollen growths on branches and twigs.
- Black Cherry Aphids: These sap-feeding insects cause leaves to curl and distort while producing sticky honeydew.
Birch Tree Pests & Diseases
Birch trees are attractive landscape specimens but are often susceptible to insects and diseases, particularly when growing in stressful environmental conditions.
- Bronze Birch Borer: This is the most significant insect pest of birch trees and can cause severe canopy dieback.
- Leafminers: These insects create winding tunnels within birch leaves that are visible from both sides.
- Anthracnose: This fungal disease may cause leaf spotting and premature leaf drop.
- Aphids: These sap-feeding insects produce honeydew that can lead to sooty mold growth.
- Root Rot: This condition may contribute to declining vigor in stressed trees.
Magnolia Tree Pests & Diseases
Magnolias are prized for their glossy foliage and spectacular flowers, but they are vulnerable to several common tree health problems.
- Magnolia Scale: This large scale insect produces copious amounts of honeydew and is frequently accompanied by black sooty mold.
- Tuliptree Scale: This related pest may also infest magnolias and contribute to declining tree vigor.
- Leaf Spot Diseases: These fungal diseases cause dark lesions on leaves and may reduce a tree’s ornamental appeal.
- Spider Mites: These tiny pests can cause bronzing and discoloration of magnolia foliage.
- Powdery Mildew: This fungal disease occasionally affects susceptible magnolia species.
Redbud Tree Pests & Diseases
Eastern redbuds are beautiful native trees that are generally easy to grow but can suffer from several common pests and diseases.
- Verticillium Wilt: This fungal disease causes wilting, branch dieback, and progressive canopy decline.
- Canker Diseases: These diseases produce sunken lesions on branches and stems that may girdle affected tissue.
- Leaf Spot Diseases: These fungal diseases may cause premature leaf drop and cosmetic damage.
- Scale Insects: These sap-feeding pests may weaken redbuds over time.
- Japanese Beetles: These insects occasionally feed on redbud foliage during the summer months.
Treatment Options for Tree Pests and Diseases
Fortunately, many tree pests and diseases can be successfully managed when they’re identified early. The right treatment will depend on the specific pest or pathogen involved, the severity of the problem, the tree species affected, and the overall health of the tree. In some cases, monitoring may be all that’s required, while others call for targeted treatments or ongoing plant health care.
- Monitoring: Not every tree pest or disease requires immediate treatment. In some cases, careful monitoring is the best way to determine whether intervention is necessary.
- Soil Treatments: Systemic products applied to the soil can help protect susceptible trees from certain insect pests by allowing the tree to absorb the treatment through its root system.
- Trunk Injections: Arborists may use trunk injections to deliver targeted treatments directly into a tree’s vascular system for certain pests and diseases.
- Horticultural Oils: These products are commonly used to manage scale insects, mites, and other sap-feeding pests by smothering them without harming the tree.
- Fungicide Treatments: Fungicides may help manage some fungal diseases when applied at the appropriate time and in accordance with industry best practices.
- Pruning: Proper pruning can improve airflow throughout the canopy, remove diseased or infested plant material, and reduce the spread of certain pests and pathogens.
- Plant Health Care (PHC): A proactive plant health care program can help improve tree vigor and reduce susceptibility to many pests and diseases over time.
- Tree Removal: In some cases, severely infested, diseased, or structurally compromised trees may need to be removed to protect nearby trees and property.
Frequently Asked Questions
Tree pests and diseases can be difficult to identify, especially since many problems produce similar symptoms. Here are answers to some of the questions Chapel Hill and Durham homeowners ask us most often.
How can I tell if my tree has a pest or a disease?
Many tree pests and diseases cause similar symptoms, including leaf discoloration, canopy thinning, branch dieback, and premature leaf drop. Identifying the tree species, evaluating the symptoms, and considering the time of year can help narrow down the list of potential causes.
What are the most common tree pests in Chapel Hill and Durham?
Some of the most common tree pests in central North Carolina include Japanese beetles, ambrosia beetles, bagworms, pine bark beetles, aphids, scale insects, and spider mites. The pests affecting your landscape will largely depend on the types of trees growing on your property.
Can healthy trees survive pest infestations?
In many cases, yes. Healthy trees are often capable of tolerating or recovering from minor pest infestations. However, severe infestations or attacks on stressed trees may require professional treatment to prevent long-term damage.
What are the warning signs that my tree is in trouble?
Canopy thinning, excessive leaf loss, branch dieback, unusual bark damage, fungal growth, and premature leaf discoloration are all common signs that a tree may be experiencing health problems. Early intervention often provides the greatest number of treatment options.
When should tree pests or diseases be treated?
Timing matters when treating tree health problems. Some treatments are most effective when applied preventively or during specific stages of a pest’s life cycle. The best treatment schedule will depend on the tree species, the problem being addressed, and the time of year.
Can tree diseases spread to other trees on my property?
Yes. Some fungal and bacterial diseases can spread to nearby trees, particularly when susceptible species are planted close together. Early identification and treatment can help minimize the risk of additional trees becoming affected.
When should I call a certified arborist?
If you’re noticing unexplained tree decline, significant pest damage, or symptoms that continue to worsen over time, it’s a good idea to schedule a professional evaluation. Certified arborists can accurately diagnose tree health problems and recommend the most effective treatment options for your landscape.
Protect Your Trees with Expert Plant Health Care
Whether you’ve noticed thinning foliage, unusual leaf spots, branch dieback, or signs of insect activity, the experienced arborists at Lubbers & Sons Tree Care are here to help. We’ll identify the underlying problem and recommend a customized treatment plan designed to keep your landscape healthy and thriving.
Contact Lubbers & Sons Tree Care today to schedule your professional tree health evaluation.
Sources and References
- NC State Extension Gardener Plant Toolbox – “Magnolia”
Horticultural profile of the magnolia genus covering species, growing requirements, native North Carolina magnolias, and common insect and disease problems.
https://plants.ces.ncsu.edu/plants/magnolia/ - Tree Care Industry Magazine – “Spotlight on Beech Leaf Disease”
Arborist-focused overview of beech leaf disease, its spread across the mid-Atlantic, New England, and upper Midwest, and current management considerations for tree care professionals.
https://tcimag.tcia.org/training/plant-health-care-strategies/spotlight-on-beech-leaf-disease/ - NC State Extension – “Common Disease Pests of Oak in North Carolina”
Diagnostic factsheet describing frequent oak diseases such as oak leaf blister, bacterial leaf scorch, and anthracnose, with symptom images and links to detailed guidance.
https://content.ces.ncsu.edu/common-disease-pests-of-oak-in-north-carolina - Hemlock Restoration Initiative – “Hemlock Woolly Adelgid”
Program resource detailing the biology, history, and impact of hemlock woolly adelgid (Adelges tsugae) on eastern and Carolina hemlocks, with links to treatment options.
https://savehemlocksnc.org/hemlocks-hwa/hemlock-woolly-adelgid/
