One of the most enjoyable aspects of trees is how clearly communicative they are. As seasons come and go, threes frequently change through displays of colors, thickness, and growth when they’re healthy. However, much like a whiney toddler with a cold, trees are also very clear communicators when they aren’t feeling well.
Even if we only check on our trees once a month, they make it clear when they are stressed by drought, injury, weather, pests, and diseases. Foliage that was once brightly colored and lush may suddenly thin and prematurely brown. Or perhaps new cankers have developed on the trunk or branches.
No matter the issues, trees will show at least some symptoms as they cry out for our help and attention. Never ignore signs that something is amiss. When it comes to fungal diseases, early diagnosing and treatment are often the only chance to save your tree.
So whether you’re worried your tree is already infected or you’re just determined to keep your trees healthy, you’ve found the right place. Here are some of the most common fungal diseases affecting trees in Dallas/Fort Worth (DFW) and how you can treat them.
Hypoxylon Canker
Cause and Affects
Relatively common in the DFW area, Hypoxylon canker is a tree disease caused by the Hypoxylon atropunctatum fungus. Hypoxylon canker is an opportunistic fungus which means it’s mainly a concern for unhealthy/sickly trees.
Hypoxylon canker attacks trees that have been stressed or weakened by weather, drought, poor nutrition, physical injury, root damage, or pests. When a tree is unhealthy, it opens the window for this fungus to cause cankers (dead lesions) on the bark, trunk, and branches.
Hypoxylon canker is most commonly present as a symptom of a sick tree. It is essentially a straw that breaks the camel’s back, pushing sick trees over into death.
Hypoxylon canker is a common occurrence during periods of drought, and trees stressed by drought are particularly susceptible. As droughts are a normal part of life in Texas, this fungus remains an issue in the DFW area.
Tree Species Affected
Hypoxylon canker affects quite a few species of trees native to North Texas. This fungus primarily attacks oaks, but it is also common on many hardwoods. The most susceptible trees include oak, elm, sycamore, and pecan.
Signs and Symptoms
- Loss of leaves beginning on the uppermost branches, leaving them looking lifeless and dead.
- Bark peeling off the branches and trunk.
- In the areas where bark has peeled away, dark spores appear. After a few weeks, the spores then disappear and gray-colored wood becomes visible. Months later, these gray areas turn black and appear burned.
Treatment
Unfortunately, trees infected with hypoxylon canker disease cannot be cured. This fungal disease is fatal for the tree and usually kills the sick tree relatively quickly.
As there is no cure for this killer of sick trees, your best option is to keep your trees healthy with preventative maintenance. In fact, the best prevention for all tree diseases is the proper and healthy maintenance of trees.
Many people think that trees require zero care or maintenance, but that is simply not the case. Continue reading to learn about proper preventative maintenance.
Fire Blight
Cause and Affects
Fire blight is a fungal disease caused by the bacterium Erwinia amylovora. This bacteria hides away in the cankers of trees through winter, laying in wait till tree growth resumes in the spring. Once tree growth picks up, the bacterium emerges in the form of a tan liquid that oozes out of the tree’s surfaces.
After fire blight invades, it could cause either a simple localized infection and die off or spread through the branches infecting the entire tree.
Fire blight often infects trees that have been injured by pests, weather, or physical damage. When tree wounds are left open and vulnerable, this fungus can easily invade. The infection and spread of fire blight occur most often with wet, humid conditions.
Tree Species at Risk
Fire blight most often attacks fruit trees. Pear trees and apple trees are particularly susceptible. Fire blight can be spread from tree to tree by means of bees and birds that frequent these fruit trees.
Signs and Symptoms
- Fire blight is so named because the leaves and blooms of infected trees blacken rapidly and appear burned.
- Leaves have brown/black blotches; leaves also curl/shrivel.
- Branches develop dark-colored cankers, and these cankers may ooze a sticky liquid.
- Twigs wilt and curl from the tip on downward, turning black and looking like a curved hook.
Treatment
Fire blight can spread very fast, but there’s no reason for it to be fatal if it’s spotted and treated. If you notice signs of fire blight on your tree, prune away the infected areas and limbs and remove any fallen leaves. Infected leaves and limbs should be carefully removed to not spread the infection further.
A great way to reduce the likelihood of fire blight spreading in your trees is to do preventative pruning in the winter before the bacteria seep out in the spring. Preventative fungicides in the winter are also effective at reducing bacteria. The best option is to have a professional lawn care company like Gecko Green treat your trees and shrubs for you.
Anthracnose Disease
Cause and Affects
Anthracnose is one of the more commonly seen fungal diseases in DFW. Although anthracnose is not usually fatal to trees, it does severely weaken them. Anthracnose can spread rather quickly, especially in the cool, wet, windy weather of spring. This fungal disease can be very problematic because as it weakens healthy trees, those trees become more stressed and vulnerable to other diseases and pests.
Tree Species at Risk
There are many hardwood trees commonly found in DFW that are vulnerable to anthracnose disease. Ash, maple, sycamore, and dogwood trees are all susceptible. However, in DFW, oaks are the most susceptible to this fungal disease.
Signs and Symptoms
- Premature defoliation, some trees may drop leaves entirely.
- Gnarled, curling leaves with brown spots along the veins.
- Cankers on twigs.
Treatment
Repeated annual defoliation severely weakens trees infected with anthracnose, so the earlier you spot this disease, the better. Treatment may or may not be necessary to keep your diseased tree alive. Fungicides do not eliminate anthracnose.
However, they are an effective way to protect the portions of your trees that haven’t yet been infected.
If your tree is infected with anthracnose, you should consider hiring a lawn care company to monitor and treat the diseased tree for you. Keeping anthracnose at bay can be tricky. A lawn care company like Gecko Green can correctly time, select, and apply treatments with more potent, commercial-grade products.
Winter pruning is also an effective way to improve tree health by removing damaged and infected branches. Although the infected leaves and branches removed may be dead, the anthracnose fungus on these dead parts can still survive and spread. For this reason, be sure to carefully remove any infected parts.
Mushroom Root Rot (Oak Root Rot)
Cause and Affects
Mushroom or oak root rot is a troublesome, widespread disease caused by the Armillaria species of fungus. As the name suggests, the fungus attacks trees’ roots, causing decay, reduced growth, stress, and weakness.
This fungus attacks weak, sickly trees as well as healthy trees. Root rot may rapidly kill the infected tree outright. However, it could also severely weaken trees over time, leaving them vulnerable to other disease and pest issues.
Tree Species at Risk
Mushroom root rot attacks a wide range of orchard and shade trees and shrubs. Some species such as chinaberry, junipers, peach, and plum are particularly susceptible.
Signs and Symptoms
- Mushrooms growing at the base of tree.
- Leaves show premature discoloration, turning yellow and brown early.
- A white fungus is visible beneath the bark. Try peeling away a piece of bark near the base to check for this white fungus.
Treatment
Overall, fungicides and treatments have not proven very effective against this aggressive fungal disease. The best way to stop mushroom root rot is to avoid it and prevent it from affecting your trees. The fungus more easily affects stressed trees, so avoid tree stress with proper care. Read our prevention section below for more tips.
Be aware that this fungus can survive for decades on dead roots. Any areas affected by mushroom root rot must be treated carefully to avoid spread. Consider hiring a lawn care company to help you with proper removal, fumigation, and treatments.
Dutch Elm Disease
Cause and Affects
Dutch elm disease is a fungal disease found in trees caused by the Ceratocystis ulmi fungus. Although this disease is not a widespread problem in the DFW region, it is still found in North Texas. Dutch elm disease is spread by bark beetles infected with the causal fungus.
Unfortunately, this fungal disease nearly always causes plant death. Tree death can be rapid or take place over several years. The fungal infection spreads from the top of the tree, working downward, and once the roots are infected, death is imminent.
Tree Species at Risk
As indicated by its name, this disease attacks elms. One of the more common and popular trees in DFW, the Cedar Elm, is susceptible to Dutch elm disease.
Signs and Symptoms
- Loss of foliage.
- Leaves wilt and yellow, beginning at the top of the tree and continuing downward
- On some trees, leaves may wilt so quickly that they dry and fall while still green.
- Some affected twigs may wilt and curl from the tip on downward, looking like a curved hook.
Treatment
Unfortunately, spotting Dutch elm disease early enough for effective treatment with products is rare. Typically, when a tree is diagnosed with this fungal disease, the only step to be taken is tree removal and chemical treatment of the region.
In some cases, pruning of infected areas and fungicide treatments can be an effective way to save the tree. Still, your best option is to contact a lawn care company for guidance.
This fungus is easily spread to other trees, so careful removal is necessary.
Bacterial Leaf Scorch
Cause and Affects
Bacterial Leaf Scorch is caused by the bacterium Xylella fastidiosa. It is one of the less common tree diseases in DFW. This fungal disease is spread by insects that carry the bacteria from affected trees to others.
Essentially, this fungal disease severely affects the flow of water within infected trees, causing them to dry out. This greatly harms the tree by restricting water flow between roots and leaves and weakens the tree making it more susceptible to other disease and pest issues
Tree Species at Risk
Several tree species in DFW are vulnerable to bacterial leaf scorch. Many oak species can be affected, such as the bur, shingle, live, pin, and more. Sycamores, boxelders, dogwoods, maples, and more are also susceptible to this disease.
Signs and Symptoms
- Leaves will begin to prematurely turn brown midsummer, and by fall, leaves will all be brown.
- The outer edges of the leaves will display a brown border. This band separates the dead tissue from the living, green tissue.
Treatment
Unfortunately, there is no cure for bacterial leaf scorch. Once the bacteria is present, proper management to delay death is the only option. This fungal disease robs trees of their ability to effectively circulate water, so supplemental irrigation and mulching is a good start. Be sure to monitor your trees for signs of disease.
If you have any infestations, you should contact a lawn care company for management guidance.
Prevention is Paramount!
Unfortunately, many of the fungal diseases that commonly affect trees in the DFW area are untreatable and fatal. Even the diseases that aren’t fatal can severely weaken your trees leaving damage that can last for years. The best way (and sometimes the only way) to protect your trees from fungal disease is prevention through proper management and monitoring.
Whether you decide to keep an eye on your trees or hire a lawn care company to keep a lookout for you, someone should regularly monitor your trees’ condition. Although many people believe that trees require little to no care, the least we can do for them is to check in on them.
Know what your trees look like when they’re healthy so you can spot the symptoms when they’re not. Early detection of illness, physical harm, disease, fungus, and wounds on our trees is their greatest hope of survival. Never overlook symptoms of sickness or damage in your trees.
In addition to regular monitoring, tree diseases can widely be prevented by keeping your trees healthy and strong. Fungal infections are primarily opportunistic, and it is much easier for them to invade a stressed, weakened tree. Adequate irrigation and watering are vital for trees, especially new plantings.
New trees require infrequent, deep watering for at least their first 2-3 years.
Mulch is also an excellent way to help your trees retain moisture and regulate soil temperatures. In times of drought in DFW, you will need to check your trees for signs of drought stress and potentially supplement all your trees with water.
Correct tree care will also require good pruning practices and proper wound care for any injuries your tree sustains. Avoid over-pruning as too many wounds provide easy access for pest and disease invasions. During droughts or dry-spells, be sure to tend to any tree wounds promptly.
Tree & Shrub Care with Gecko Green
Without proper care, trees and shrubs start to weaken. Finding the time and energy to monitor and maintain healthy trees can be challenging. Our tree and shrub care program for North Texas is thorough and comprehensive, with eight strategically timed visits a year.
Our professional teams are equipped with the experience and agronomical knowledge to keep your trees thriving year-round. Call Gecko Green today for a free quote!
