Tree diseases are illnesses in trees and shrubs caused by fungi, bacteria, and environmental stress such as extreme temperatures, drought/flooding, broken branches, and pollution. Our Certified Arborists are trained in diagnosing and treating tree diseases. After evaluating the trees and shrubs on your property our experts will create a customized program to treat the disease and suppress it from reoccurring in the future.
Common Tree Diseases in the Mid-Atlantic
Anthracnose & Leaf Spot Diseases:
Leaf spot is a common term used to describe a number of diseases that creates spots on the foliage of trees and shrubs. Leaf spots are most commonly caused by fungi but can be caused by bacterial infections as well. One of the most well-known leaf spot diseases in our area is called Anthracnose.
The main symptom of leaf spot diseases is lesions on the tree’s leaves. Spots will vary in size and color depending on the specific kind of leaf spot the tree is infected with; however, most spots tend to be brownish. Aside from its unsightly appearance, it can cause early leaf drop as well as wilting and curled leaves,
Targets: Dogwoods, Ash, Oaks Sycamores, Maples, and other deciduous hardwoods.
Bacterial Leaf Scorch:
Bacterial Leaf Scorch the bacteria Xylella fastidiosa. The bacteria attack shade trees and clogs the tree’s xylem. Xylem is one of the two types of transport tissues in trees; by clogging these tissues the bacteria restrict the flow of water from the roots to the tree’s crown. This results in dehydration and causes the tree’s leaves to brown and appears to be under drought stress even when the tree has access to enough water.
Bacterial Leaf Scorch is a chronic disease that if left untreated will cause dieback, secondary invaders, branch death, and ultimately death.
Targets: Oaks, Elms, Sycamore, Sweet Gum
Dutch Elm Disease:
Dutch Elm disease is caused by a fungus spread by the elm bark beetle. Historically, it is one of the most destructive diseases to shade trees in North America. Out of the 77 million elms in North America in 1930, over 75% had been lost by 1989. The Elm population across the United States is still battling this detrimental disease.
Dutch Elm Disease causes leaf wilting, curling, and yellowing of leaves, leaf drop, and will eventually kill your tree.
Fire blight is a common and destructive disease caused by the bacterium Erwinia amylovora. The infection enters the tree through open flowers and new shoots in the spring.
Fire blight causes leaves to blacken and curl giving a fire-scorched appearance. It can cause lesions on fruits and cankers on the branches and trunk. Without proper treatment, infected trees will die.
Targets: Apple, Crab Apple, Pears, Hawthorn
Oak wilt is a disease caused by the fungus Ceratocystis fagacearum. It can spread through insects and connections between tree roots, there are no resistant or immune oak species. Oak wilt can kill a tree within a single season!
Oak wilt causes leaf discoloration, wilt, defoliation, and ultimately the death of the tree from the top down.
Targets: All species of oaks. Red oaks succumb to the disease faster than white oaks.
Powdery mildew is a fungal disease affecting a wide variety of plant species. While powdery mildew alone is not lethal, it does weaken trees and creates an unsightly appearance. This fungus spreads through spores carried by the wind and rain.
The infection begins as round white spots on leaves and stems. Then, as the fungus spreads, it appears as white/gray dust that encompasses most of the tree. Leaves may become curved or twisted and can prematurely turn yellow.
Targets: Dogwoods, Crape Myrtles, Ash, Roses, Elm, Maple, Magnolia, Oak, Euonymus, and more.
Sooty Mold & Honeydew:
Honeydew is the excrement of plant-sucking insects such as scale and aphids. Many homeowners confuse honeydew with sap. Trees do not drip sap. If you have “sap” dripping from your tree it is honeydew and is a telltale sign of an insect infestation.
Sooty mold is a fungus that grows on top of honeydew and coats the leaves of your trees to the point where they can no longer absorb sunlight. This interrupts photosynthesis and the tree will not be able to produce the nutrients they need for survival. If your trees and shrubs turn black, you most likely have a sooty mold problem caused by an insect infestation.
Targets: The insects that cause honeydew and thus sooty mold to develop target hundreds of species. The most susceptible species in this area include; Maples, Oaks, Linden, Birch, Crape Myrtles, Ash, and Tulip Poplars.
Verticillium Wilt is a disease caused by the soil-borne fungi Verticillium albo-atrum and Verticillium dahliae. The fungus invades through the roots of susceptible trees and shrubs and then spreads through the plant’s vascular system. Once the Xylem, the tree’s water transportation system, is infected it becomes clogged and water can no longer reach the tree’s leaves. Verticillium is common and affects several hundred species of trees and shrubs.
Verticillium Wilt causes leaf curling, drying, small yellow foliage, leaf scorch, and slow growth. Often times the symptoms are seen on one side or section of the tree.
Targets: Ash, Azalea, Cherry, Certain species of Dogwood or Linden, Locust, Magnolia, Maple, Oak, and Redbud.
How Often to Check Your Trees for Disease or Damage
With many tree diseases, early detection is vital in keeping your tree healthy. Your trees should be checked at least three times a year – once at the start of the growing season, once throughout the season, and then a final check before winter. Some diseases can spread quickly and cause irreversible damage. It’s important to always keep an eye on your plants, but with a busy schedule that is not always realistic.
That’s why we designed our Plant Health Care Inspections, which allows our environmental experts to inspect and treat your property throughout the growing season! With our Canopy Protection Program. we will be on-site at least seven times throughout the year, which allows us to closely monitor the development of any pests or diseases. You can be at ease knowing someone is keeping a close eye on your yard!
Not interested in a complete canopy program? No worries, there are still signs and symptoms you can look for on your own! If you notice any unusual changes to your trees, be sure to reach out to our experts as soon as possible, to see if treatment is necessary.
How to Perform a Tree Examination
There is nothing wrong with taking the time to inspect your tree on your own! We rely on diligent homeowners to let us know if there are any sudden changes to their trees in between our healthcare visits. There is no hard and fast checklist of what to do, but take the time to look at your tree up close. First, inspect the bark for holes, cracks, or patches of decay. Stand under your tree and look directly up into the canopy – do you see a lot of dead branches or areas not leafing out? Then look down at the roots – any roots encircling the base can harm your tree. While you are taking the time to look at your beloved plants, be sure to look out for these common symptoms!
Common Signs of Tree Diseases
Canopy dieback refers to the decline of a tree’s canopy. When you step back and look at your tree it may look sparse and not as full as other trees during this time of year.
Cause: Canopy dieback is a sign of overall health decline. This can be caused by an insect or disease, old age, stressors such as drought, extreme weather, and soil compaction.
|Early Leaf Drop:
Early leaf drop refers to the leaves of your trees falling during the spring and summer.
Cause: It is important to notice this symptom as it is often associated with serious root and soil disorders. Early leaf drop can also indicate vascular diseases and boring insects.
Exit/Entry Holes:Exit or Entry holes are small holes in the bark of your tree, typically round, oval, or d shaped.
Cause: These holes are a sign that your tree is infested with boring insects. Some pests can carry fungi and diseases which can infect your tree.
|Leaf Discoloration & Spots: Leaf discoloration and spots refer to the overall browning and yellowing of leaves, and leaves with colored spots.
Cause: Spots and discoloration can be indicators of many issues including drought, disease, insects, and root issuesPhoto Credit: Paul Bachi, University of Kentucky Research and Education Center, Bugwood.org
Noticing other symptoms on your trees? Check out these 8 Signs Your Tree is Sick for more info!
Normal Tree Variations Not to be Concerned About
As a typical homeowner, it can be difficult to tell the difference between changes in your tree that indicate illness and normal changes throughout seasons and their lifespan. Here we will go over what are common health symptoms and what signs are typically not alarming.
Trees normally have a little lean to them. The trunk of a tree curves because of the tree’s ability to adapt over time to the changing availability of sunlight. The tree’s root system will grow to accommodate this off-center weight distribution. However, if a tree suddenly begins to lean, starts leaning after a storm, if the soil around the tree is heaving, or if there are gaps in the soil near the stem of the tree the tree may be at risk of falling.
If you spot insects on your property such as bees, ladybugs, green lace wigs, or praying mantis you don’t need to worry. These bugs are what we call beneficial insects. Beneficial insects are species that perform valued services like pollination and pest control. These insects will police your landscape and keep harmful insects that want to hurt your trees and shrubs in check.
In most cases, bark coming off of a tree is not a good sign, however, it is perfectly normal for crepe myrtles! If you didn’t grow up seeing the bizarre phenomena of bark peeling off of crape myrtles, then it would understandably be alarming. Have no fear, this is normal healthy behavior for them!
How to Treat Common Tree Diseases
Although trees have natural immune systems, there are many times when Mother Nature cannot heal the trees on your property. In these cases fungicides, antibiotics, or other forms of treatment may be applied through injections, spraying, or soil drenches to control insects & diseases. Our Certified Arborists are trained, licensed, and experienced in diagnosing and treating tree insects and diseases using our SmartTreat™ Process. Our Arborists will create a customized program to treat the disease and keep it from reoccurring in the future. As always, we recommend preventative care to help your tree stay healthy all year long to resist infection from pests and diseases!
What Is The SmartTreat™ Process?
RTEC’S SmartTreat™ process is a highly effective and environmentally sensitive approach to pest and disease management in our suburban environment. The SmartTreat™ process uses the life cycles of pests and their interaction with the environment to provide more effective pest management solutions all while using fewer chemicals on your property.
Tree Diseases can progress rapidly. As soon as you see signs that your tree is diseased call an Arborist to come to take a look. If left untreated, over time the damage can become too extensive and the tree or shrub may not be able to be saved through disease treatments.
Need Help With A Tree Disease?
Meet With An Arborist Or Call 703.573.3029 To Book An Appointment Via Phone
Worried your tree is infected with a tree disease? Use our online booking system or call 703.573.3029 to schedule a consultation with an arborist to diagnose your tree disease.