Apple Cotton Root Rot Control: Treating Apple Cotton Root Rot Symptoms

Cotton root rot of apple trees is a fungal disease caused by a very destructive plant disease organism, Phymatotrichum omnivorum. If you have apple trees in your backyard orchard, you probably need to learn about apple cotton root rot symptoms. Read on for what to look for if you have apples with cotton root rot, as well as information on apple cotton root rot control.

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.

Teo Spengler

Teo Spengler has been gardening for 30 years. She is a docent at the San Francisco Botanical Garden. Her passion is trees, 250 of which she has planted on her land in France.