Helpful Tips About Trees, Lawns, and Pests

4 Facts About Thousand Cankers Disease & Which Trees It Affects

Written by Joshua Malik | May 25, 2023 1:07:39 PM

When it comes to the trees on your Pennsylvania property, you want peace of mind that they’re going to live a long and healthy life. After all, your trees are an important part of your landscape.

Unfortunately, tree diseases can cause a lot of frustration and trouble. If leaves start turning colors or falling off, your tree could be infected by a disease such as thousand cankers disease.

We do see thousand cankers disease in trees and it’s important to understand what it is and what to do about it.

Facts about Thousand Cankers Disease

Here are a few things that can help you better understand this disease.

#1: It is caused by a Fungus AND a Pest

First and foremost, you want to know what is thousand cankers disease?

This disease is unique in that it’s caused by the combined action of a disease and a pest. Thousand cankers disease is caused by the fungus-carrying Walnut Twig Beetle. 

This pest is known to tunnel beneath the bark of walnut trees and create small cankers by spreading the fungus as the beetles feed inside the bark.

Over time, repeated attacks and growing cankers can start to cause serious trouble for your tree.

#2: Early Thousand Cankers Disease Symptoms Include Yellowing Leaves

Unfortunately, this disease can be difficult to diagnose since the problem is happening within the tree bark.

Early thousand cankers disease symptoms are yellowing, wilting leaves…and sometimes dead limbs in the upper area of the tree. 

Of course, those symptoms can be caused by other tree problems, which is why a professional diagnosis is important.

Upon close inspection of your tree, you might notice the beetle entry holes or even the discolored cankers beneath the bark.

#3: It is Especially Lethal to the Black Walnut Tree

You might also want to know what trees are affected by thousand cankers disease.

This disease primarily affects the Black Walnut (though it can affect other types of walnut trees, too). 

Unfortunately, in terms of its ability to do damage, it is the most lethal to the Black Walnut. In fact, since this disease was first discovered, it has caused the widespread death of many Black Walnuts across the country.

#4: There is No Cure for Thousand Cankers Disease

In terms of thousand cankers disease treatment, there is no cure for this disease. If your tree is determined to be infected, the best course of action is typically management of its overall health.

If your tree has not already been ravaged by disease, proper irrigation and fertilization can help maintain its overall health for the time being.

If we come to see your tree after this disease has already taken an aggressive hold, it may be too late, leaving tree removal as your best option.

Tree disease does not always mean death and there are some diseases that have cures and treatments. But when death is imminent, it is safer to remove your tree than to take any risks that it could fall.

While tree leaves that are black or falling off are an eyesore, disease that has progressed can also cause more serious problems such as decaying or dead tree limbs that pose a risk of falling.

Even when it’s not that severe, some trees may never fully recover from being stricken with a disease, like thousand cankers. They may look sickly or aesthetically unappealing for the rest of their life, leading you to choose to remove them based on appearance, which is a reasonable decision.

Choosing An Arborist to Care for Your Trees

While tree leaves turning yellow or wilting could be symptoms of a disease like thousand cankers, the truth is, you won’t know for sure until you have an expert evaluate your tree.

There are other pests or environmental stressors that can cause similar damage as well.

This is why it’s incredibly valuable to partner with tree care services that you truly trust. This would mean choosing a tree care service that employs Certified Arborists on staff.


When you have a Certified Arborist visiting your property regularly, you can gain peace of mind that they’ll spot potential problems early and develop action plans appropriately. Yes, sometimes that action plan might mean tree removal. But other times, there are diseases that can be treated and/or cured.

Once you get the proper diagnosis in place, you can move forward with the best plan for your property.

Choosing Joshua Tree Experts for All of Your Tree Concerns

At Joshua Tree Experts, this is something that we take seriously.

We know that tree issues like disease can be complex and really do require an expert opinion. Having a Certified Arborist from Joshua Tree will help you feel confident that your tree needs are being properly met.

At the end of the day, your wise choice in selecting an experienced tree service will allow you to cast your fears aside. With a true tree care expert handling your mature trees, there simply won’t be any reason to worry.

With the right care for your trees, you’ll gain valuable peace of mind. If you’re interested in having your trees inspected and their health assured, contact us for a free consultation or give us a call at 833-JTE-TREE.

Image Source: tree with thousand cankers, leaves with thousand cankers