Cylindrocarpon macrodidymum

Cylindrocarpon macrodidymum is a soil-borne fungal pathogen belonging to the kingdom Fungi, phylum Ascomycota, and family Nectriaceae. It is now frequently associated with the Ilyonectria species complex, which is recognized as a major cause of root infections in various perennial woody crops. This pathogen is considered a significant threat to agricultural productivity worldwide.

The fungus primarily targets crops such as grapevines (Vitis vinifera), apple trees, and kiwifruit. It is known to cause severe root rot, basal necrosis, and vascular decay, which are often referred to as black foot disease in vineyards. The destruction of root tissue prevents the plant from absorbing vital nutrients and water, leading to a general decline in plant vigor.

The biology of Cylindrocarpon macrodidymum is characterized by its ability to persist in the soil for extended periods as chlamydospores. These resting structures are highly resistant to adverse environmental conditions. Infections typically occur through root wounds or natural openings when the plant is stressed by excessive soil moisture, poor drainage, or cold temperatures.

The economic impact of this pathogen is severe, especially in young plantations where it can lead to high rates of mortality. Infected plants show stunted growth, leaf chlorosis, and reduced yield. As the disease progresses, the entire root system may become necrotic, making it impossible for the plant to recover or sustain itself, ultimately resulting in the loss of entire orchard or vineyard blocks.

Effective management and control strategies include the following practices:

• Prioritizing the use of clean, certified, and disease-free nursery stock.
• Improving soil drainage to prevent conditions favorable for fungal growth.
• Sterilizing pruning tools to prevent the mechanical spread of spores.
• Applying fungicides during the nursery propagation phase or at planting.
• Implementing integrated pest management (IPM) to maintain plant health and vigor.