Often, a tree may have a few leaves with spots, yet may not suffer significant setbacks due to this mild condition. Trees have thousands of leaves, after all, and can afford to lose a few. If your tree has a lot of leaf spots and seems to be dropping a high percentage of leaves due to the spots, it may need help. You'll want to have a professional come out to take a look and provide your tree diagnosis for its spots.
Here are some of the methods and strategies a tree care professional may use in this situation when facing a tree with spotted and damaged leaves.
Inspecting the spots' appearance
Different types of diseases and pests often cause different spots with different sizes, shapes, or colors. For example, a fungal leaf spot disease called Phyllosticta leaf spot causes spots that start out yellow and eventually turn black in the middle. These spots can be quite distinctive looking.
So in some cases, simply looking at the spots can allow an experienced tree care contractor to make a fairly accurate diagnosis. The professional will also check to see if any insects on the leaves appear to be related to the damage. For example, spider mites can cause spotting and stippling, and scale insects can be mistaken for spots themselves.
Checking the tree's surroundings
The surroundings can sometimes give a clue as to what may be causing the spots on your tree's leaves. For instance, a tree could suffer leaf spots due to a root problem or a vascular problem. Some possible issues in this category include root rot, which can cause yellowing and spotted leaves, and verticillium wilt, which can cause blotchy brown spots.
Root rot can often come about because a tree is planted in an area that has dense, poorly drained soil or in a low spot that all the water in your yard drains to. Then, the tree's roots don't get enough oxygen, and the fungal infections can thrive. So checking the tree's environment and surroundings can sometimes be key to identifying what's ailing it.
Trying antifungal treatments
In some cases, leaf spots may be obviously disease-related, but not easily identifiable as any specific bacteria or fungus. In this scenario, simply treating with an antifungal may function as a diagnostic step. Most leaf spot diseases are caused by a fungus rather than by bacteria, so a good antifungal treatment has a high chance of being effective.
If the treatment works, you can assume the issue was a fungus as expected. If not, your tree care professional may move on to the next step.
Sending a sample to a lab
If a tree's problem isn't easily identifiable, laboratory analysis may be needed to figure out what's going on. Tests, looking at the sample under the microscope, and similar procedures can often uncover the culprit. Your tree care professional may decide to send a sample to a lab for analysis if leaf spots are causing serious damage and proving tricky to identify.
The downside of sending a sample to a lab is that you'll likely have to wait a while for the sample to arrive at the lab and get processed. If your tree is severely damaged, though, that may not matter. You may decide to remove the badly damaged tree, and may simply want to know what went wrong so you can protect your other trees and avoid a reoccurrence.
These are some of the ways that your tree care professional may choose to work towards a diagnosis for your tree if it's suffering from spotted leaves. Keep in mind that some leaf spot conditions can look very similar to each other. So if your tree is struggling, you'll want to contact a professional for a diagnosis rather than trying to treat the problem on your own.
Reach out to a tree diagnosis professional for more information.
