Why Is My Ash Tree Dying? A Closer Look At The Causes

If you have an ash tree in your yard, you may have noticed some concerning signs of decline.

Ash trees are typically strong and resilient, so when they start to die, it can be alarming.

In this article, we will take a closer look at why your ash tree may be dying and what can be done to restore it.

We will explore the causes of ash tree death, such as borers, ash yellows, and ash anthracnose, as well as preventive maintenance and treatments for diseased ash trees.

So if you are worried about your ash tree, read on to learn more.

Short Answer

It is difficult to say why your ash tree is dying without knowing more information.

Common causes of dying ash trees include diseases, pests, environmental stress, and improper planting.

It is also important to consider if any construction or other activities have taken place in the vicinity of the tree.

If you still can’t figure out why your ash tree is dying, it is best to consult a certified arborist for an expert opinion.

What Causes Ash Trees to Die?

Ash trees are extremely susceptible to a variety of diseases, pests, and environmental stressors.

These can range from infestations of borers, to diseases such as ash yellows and ash anthracnose, to extreme weather conditions that cause premature defoliation and branch dieback.

In severe cases, all of these factors can lead to the eventual death of the entire tree.

Ash borers are small, wood-boring beetles that feed on the sapwood of ash trees.

These insects can cause extensive damage to the tree over time, leading to gradual decline and eventual death.

Ash yellows is a systemic disease caused by a phytoplasma, which can be spread by leafhopper insects.

This disease causes yellowing of the leaves, premature defoliation, and stunted growth.

Ash anthracnose is a fungal disease which causes leaf spots, defoliation, and branch dieback.

Environmental stressors such as extreme temperatures, drought, and soil compaction can also contribute to the death of ash trees.

If the tree is not given the proper care, such as regular pruning and fertilization, it can become more susceptible to these stressors and lead to premature death.

It is also important to immediately address any symptoms of disease or pests to keep the tree healthy and increase its lifespan.


Borers are a common and destructive pest of ash trees.

These small, wood-boring insects tunnel through the trees bark and sapwood, leading to a weakened tree structure and eventual death.

Symptoms of borer infestation include thinning or yellowing leaves, wilting branches, and small holes in the bark.

In severe cases, infested trees may be covered in sawdust-like frass.

To prevent borer infestations, it is important to regularly inspect ash trees for signs of infestation and address any issues promptly.

Pruning dead or dying branches and bark crevices, as well as removing any fallen debris from the area, can help to reduce the risk of borer infestation.

Additionally, it is important to use an insecticide to treat borer infestations and protect the tree from further damage.

Ash Yellows

Ash Yellows is a disease that affects ash trees and can cause premature defoliation, branch dieback, and eventual death of the entire tree.

It is caused by a phytoplasma, a type of microscopic organism similar to bacteria, which is spread by leafhoppers.

The disease affects the trees vascular system, preventing it from getting enough nutrients and water to stay healthy.

Symptoms include yellowing of the foliage, wilting, and stunted growth.

The disease is often difficult to diagnose since the symptoms look similar to other illnesses.

The best way to prevent Ash Yellows is by controlling the leafhopper population.

This can be done by using insecticides, or by removing any infected trees from the area.

Additionally, it is important to monitor the tree for signs of disease, and prune any infected branches to keep the tree healthy.

If the tree is already infected, there is no cure, but proper tree care can help to minimize the damage and prolong the trees lifespan.

Ash Anthracnose

Ash anthracnose is a fungal disease that affects ash trees, causing premature defoliation and branch dieback.

This disease is caused by a pathogen known as Gnomonia fraxini, which is found in the environment and can spread to ash trees through contact with infected leaves or branches.

Signs of ash anthracnose infection include dark, dead spots on the leaves, as well as yellowing and wilting.

Over time, the disease can cause defoliation and branch dieback, resulting in the eventual death of the tree.

It is important to take steps to prevent and treat ash anthracnose in order to keep your ash trees healthy and increase their lifespan.

This includes avoiding planting ash trees in areas with poor drainage, as wet soil can contribute to the spread of the disease.

Additionally, regular pruning and fertilization can help to reduce the risk of infection, as can removing any infected leaves and branches as soon as possible.

Using a fungicide can also help to control the spread of the disease, although it is important to follow the instructions carefully to avoid harming the tree.

With proper care and attention, you can help to ensure the health and longevity of your ash tree.

Preventative Maintenance

Preventative maintenance is key to keeping your ash tree healthy and preventing it from dying prematurely.

Regular pruning can help to keep the tree in good condition and reduce the risk of disease and pests.

Pruning should be done at least twice a year, in the spring and fall, to remove any dead, diseased, or broken branches and promote new growth.

Regular fertilization is also important to ensure the tree receives the nutrients it needs for healthy growth.

Fertilizing should be done at least once a year in the spring to provide the necessary nutrients for the trees growth.

Additionally, it is important to check the tree periodically for signs of pests or disease, such as unusual defoliation or discoloration of the leaves.

If any symptoms are noticed, it is important to take immediate action to address the problem and prevent it from spreading.

Signs of Disease and Pest Damage

When it comes to diagnosing why an ash tree is dying, some of the most common signs of disease or pest damage include premature defoliation (leaves turning yellow and dropping off before their normal fall coloration), branch dieback (dead or dying branches), and bark splitting or discoloration.

In addition to these visible signs, other clues may include woodpecker activity, the presence of sap-feeding insects, and the presence of fungal fruiting bodies.

Premature defoliation is often caused by diseases like ash yellows and ash anthracnose.

Ash yellows can result from a phytoplasma infection which is spread by leafhoppers, while ash anthracnose is caused by a fungal infection.

Both of these diseases can cause leaves to yellow and drop prematurely, and can eventually lead to branch dieback and tree death.

Borers are another common problem that can cause ash tree death.

These tiny insects bore into the tree and feed on the sap within, leading to weakened branches and dead patches.

Woodpeckers tend to be attracted to trees with borer activity, as they feed on these insects.

If you notice woodpecker activity near your ash tree, it could be a sign of borer infestation.

Finally, the presence of fungal fruiting bodies can also indicate a problem.

Fungal fruiting bodies are mushroom-like structures that form on the trunk and branches of the tree and are a sign of infection.

When this happens, it is important to take immediate action to address the issue and save the tree from further damage.

Treatments for Diseased Ash Trees

If an ash tree is showing signs of disease, it is important to take action as soon as possible to help it recover.

Depending on the type of disease present, there are a few different approaches that can be taken to treat a diseased ash tree.

For diseases caused by insects or other pests, such as borers, chemical treatments are often the most effective.

These treatments may include applying a pesticide to the tree, or injecting the tree with an insecticide.

It is important to consult an expert to determine the best treatment for the type of pest that is affecting the tree.

For diseases caused by fungi, such as ash yellows or ash anthracnose, fungicides may be necessary.

These treatments should be applied every two weeks to ensure that the fungus is eliminated.

Additionally, it is important to keep the tree as healthy as possible by ensuring that it is getting enough water and nutrients.

Finally, it is important to practice good tree care to help minimize the risk of disease in the future.

This includes regular pruning, fertilization, and avoiding excessive amounts of stress on the tree.

With proper care and regular monitoring, an ash tree can be kept healthy and vibrant for many years.

Final Thoughts

It is essential to take preventative maintenance steps to protect your ash tree from the various diseases, pests, and environmental factors that can lead to its death.

Regular pruning and fertilization can help to minimize the risk of these problems.

Furthermore, if you notice any signs of disease or pest damage, it is important to take quick action to address the issue and keep your tree healthy.

With the right knowledge and care, you can ensure that your ash tree will remain healthy and strong for years to come.

James Brown

James is a specialist in plants and a gardener. He spends practically all of his time cultivating and caring for plants. He currently has a large variety of plants in his collection, ranging from trees to succulents.

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