During the hot Texas summer, plants can struggle with a pool of pathogens. Tubakia dryina, also known as Actinopelte Leafspot, is a pathogen most prevalent in red oaks but it can also infect white oaks and other oak variations. This disease can endure the mild Texas winters. Overwintering spores are dispersed once the summer rolls around. The spots are generally small (2 to 5 mm in diameter). They are round and reddish-brown in color. Some have a yellowish halo that surrounds the infection site. The disease is most severe in late summer and early fall.
Those spores that get dispersed in summer occur when it’s moist and wet. Since we’ve had a lot of rain this year, you might see it popping up on your oak trees. Usually symptoms occur at the bottom of the tree or within the trunk. They are the most favorable areas for the pathogen.
Actinolpelte leafspot is known to show up on trees that are under immense stress. If a tree is low in iron, it can become susceptible to Actinopelte leafspot. The fruiting structures can spread to leaf veins where they cause the most damage. They can kill leaves. Sometimes severe defoliation occurs. Actinopelte leafspot can infect trees that have fallen off the tree as well as leaves that are still on it so you’ll want to remove both the infected leaves on the ground as well as those on the tree.
On occasion, Actinopelte leafspot can be confused with Anthracnose, which we dealt with last week. (For more information on Spot Anthracnose, visit this article.) However, the spores from this disease are rather distinctive and can be easily deciphered under a microscope. Remember, we don’t diagnose tree diseases, but if your tree is sick, we can figure out the best course of action to take.
This disease can cause extensive damage, but it is not usually fatal to the live oak. Infected leaves should be destroyed and the tree should be fertilized slightly more than normal to stimulate new, healthy growth. Check your foliage for minor element deficiency. Newly planted trees, those planted within the first three years, are more subject to attack by this disease than well-established trees.
At Austin Tree, we will help you get your tree back to good health. If your tree has a fungal disease like Actinopelte Leafspot, we will make sure to get rid of the foliage infected. We will also suggest fertilization for your trees. Please call us at 512-341-8888. Again, we don’t diagnose tree diseases but we can treat infected trees.