How to recognize and combat white rot or downy rot in pome fruit trees

Rosellinia necatrix is ​​a pathogenic fungus that causes the disease known as white or woolly rot in pome fruit trees. This fungus is characterized by its ability to survive in soil and infected plant remains for long periods. It produces sclerotia, resistance structures that allow it to persist in adverse conditions. When humidity and temperature conditions are favorable, the fungus germinates and forms mycelium, which colonizes the roots of the plants. The mycelium of R. necatrix is ​​white and cottony, hence the common name of the disease. As the fungus invades the root tissues, it degrades the cellular structure, causing necrosis and eventually death of the plant. On the surface of the soil, a white mycelial layer can be observed, which is indicative of the presence of the fungus. Additionally, R. necatrix has the ability to produce spores that are dispersed through water and contact with contaminated tools, perpetuating infection in the orchard.