What is Apple Cotton Root Rot?
What is apple cotton root rot? It’s a hot-weather fungal disease. Apple cotton root rot symptoms usually appear from late June through September with the high summer temperatures. Cotton root rot of apples is caused by a fungus that can attack some 2,000 species of plants, including apple, pear trees, and other fruit, as well as nut and shade trees. The disease is also called phymatotrichum root rot, Texas root rot, and ozonium root rot. The fungus is prevalent in calcareous clay loam soils with a pH range of 7.0 to 8.5 and in areas with high summer temperatures.
Symptoms of Apples with Cotton Root Rot
Unlike root rot that is caused by excess water in the soil, cotton root rot symptoms are caused by the specific fungus. The disease travels in the soil and can cause enormous damage to cotton and other crops in the south. Symptoms of apples with cotton root rot include bronzing of leaves followed by rapid plant dieback. The trees suddenly turn dark shades, then the foliage and branches crisp. Another symptom often used to establish the cause of death is fungal strands on affected apple tree roots. This is usually done when the dead tree is being removed.
Apple Cotton Root Rot Control
Unfortunately, apple cotton root rot control methods are not very effective. In apple trees, no control methods have proved consistently reliable. Some gardeners, recognizing that this root rot is prevalent in alkaline soils, try to acidify the soil as a method of apple cotton root rot control. If you wish to try this, add massive amounts of sulfur to the soil before planting your trees. A more reliable method of apple cotton root rot control is planting resistant plants. Unfortunately, few, if any, apple varieties fall into that category.
