Tree disease has been an ongoing problem for landscapers for decades and can be a costly and dangerous expense. There are several things you should look for when trying to determine which or if a tree is infected with the nearly one hundred diseases that have been known to infect trees. Knowledge of what to look for will assist you in diagnosing a diseased tree and allow you to take the appropriate steps to remove and trees that are infected.



Many factors that would lead you to believe a tree is diseased could just be contributed to birds, rodents, insect, hail damages as well as nutritional deficiencies and herbicidal injury. The more information you can obtain in the diagnosis of the disease will better allow you to assess the damage of your tree.

The symptoms of most tree diseases will vary from season to season. Make sure you are aware of what diseases are common in your geographic region and what seasonal symptoms these diseases possess. When trying to diagnose a tree it is vital to gather the freshest sample possible of the area of the tree you believe to be infected.

When diagnosing a tree for disease, one should take a systematic approach by looking at the entire tree including foliage, trunk, and branches. Consider root problems as a possible cause of most above ground problems such as abnormally colored leaves, spots or bumps in foliage, premature falling of the leaves, and deformed leaves.

Looking at the leaves of a tree is the obvious way to determine a tree is diseased. Are the leaf margins brown or discolored, do the leaves have holes, or are leafs misshapen? These could all be attributed to many things including disease of the tree. Compare the leaf findings to the symptoms of the tree disease found in your area to better diagnose what disease your tree could be infected with. Make certain to look for the freshest leaves on your tree to make sure you are getting a good sample of the problem and this will help exclude insect and bird damage as the culprit.

The second thing to consider when diagnosing a tree is the trunk and branches of the tree. Is there obvious injury to the trunk caused from machinery, vehicles, or animals? Check the bark on the trunk for insect activity including holes, tunnels, and chewing marks to eliminate these as factors for the tree's problems. Wet, sticky substances leaking from the side of the trunk would be one sign a person would look for to determine the wood has been infected with a disease or bacteria. Check the trunk for any obvious signs of decay or hollowing of the trunk as these too are symptoms common with many tree diseases. Peel back a portion of the trunk bark and examine the wood inside for coloration. If the wood is made up of brown or green streaks then it is possibly infected with a disease or virus. Once again, after compiling the list of symptoms from the examination of the tree trunk and branches, consult your list of local tree diseases to find out which diseases carry these symptoms.

Finally, when trying to determine if a tree is diseased, you should closely inspect the roots of the tree. Many symptoms that would cause a person to believe a tree is diseased can be quickly attributed to problems at the tree's roots. You need to determine if the roots were planted to shallow, have there been any physical injury to the roots, has the soil or terrain around the roots changed, has nearby soil been greatly compacted by a walkway or patio, have any plants or shrubs been planted nearby, has the soil become increasingly wet or dry, or have deicing salts been used near or around the area of the tree. All of these factors could result in damage to the above ground parts of the tree. After carefully inspecting the root system of the tree, you may easily be able to determine that your tree may not be infected but rather the root system is not in good condition.

In order to properly diagnose a tree with disease you must also need to know the exact species of the tree. Several diseases are related to specific trees and knowing which tree you are examining will decrease the number of diseases you will need to research. After looking closely at the leaves, trunk and branches, and the entire root system you should be able to properly diagnose your tree with the diseases that are prominent in your geographic area. Make sure take into account any symptoms of the tree that you discovered during your inspection and compare those symptoms to the ones produced by the various diseases.