Have your tree's leaves begun to develop brown, splotchy spots? In most cases, this symptom is caused by anthracnose, a fungal infection that can affect trees, garden plants and even grasses. The good news is that anthracnose is usually quite harmless. It should not kill your tree, but if you want to get rid of those ugly leaf splotches, there are ways to treat the condition.
What Causes Anthracnose?
Anthracnose can be caused by several different fungal species, including Colletotrichum gloeosporioides, Discula fraxinea and Apiognomonia errabunda. Various species of fungi infect different species of trees.
Usually, anthracnose appears after a prolonged season of wet weather. The older leaves and those located on the exterior of the tree may remain symptom-free, but inner leaves develop spots due to a lack of air circulation and constant moisture. Anthracnose fungi, like most fungi, requires moisture to thrive.
What Other Symptoms Does Anthracnose Cause?
If you look closely at a tree with splotchy leaves, you may also notice that the twigs have developed little sores on their ends and sides. This symptom is known as twig blight, and it happens in some, but not all cases of anthracnose.
In Chinese elm trees, anthracnose can cause cankers, which are like large ulcers, to form on the branches and trunk of the tree. In this case, anthracnose can be more dangerous, since the cankers may eventually girdle a branch or the trunk, causing that branch or the entire tree to die.
What Should You Do to Get Rid of Anthracnose?
There is not much you can do to get rid of anthracnose during the current growing season, but you can take steps to keep it from returning next season.
Start by promptly raking and disposing of any leaves that fall from the tree. Rake every week or two during the fall rather than waiting for all leaves to drop. The fungus that causes anthracnose spends the winter in the fallen leaves before re-infecting the tree the following spring, so getting rid of the leaves helps eliminate the fungus.
Also, have your tree trimmed to remove some of the branches toward the interior. This increases airflow through the branches, which helps keep the leaves dryer and therefore less susceptible to infection. Winter is the best time to trim trees since they are dormant and will suffer less sap loss.
If you have a Chinese elm tree impacted by anthracnose, you'll need to treat the disease a bit more aggressively. Have a tree care company come prune away branches that have developed cankers. This helps prevent the fungus from spreading to other branches. If cankers start appearing on the trunk, your tree care professional may recommend removing the tree.
How Can You Prevent Anthracnose?
If your trees are currently symptom-free, then you should take preventative measures to keep them that way. Anthracnose is less likely to strike healthy trees. Fertilize your trees once or twice a year, keep a good layer of mulch around them, and have them trimmed annually to keep them in good health, enabling them to more easily fight off the anthracnose fungus.
Keeping your yard dry will also reduce the risk of anthracnose. If you tend to get standing water, work on improving your yard's drainage by installing drain tile or digging some new ditches.
It's never fun to find out your tree has a fungal infection, but in terms of tree diseases, anthracnose is a minor one. With the right care, your tree will recover and be symptom-free next year. If your tree has developed some spots on its leaves or you want to prevent this disease in the future, contact Vista Tree Service Inc to schedule a trimming appointment today.