Marasmius plicatulus

Marasmius plicatulus is a fungal pathogen that can affect various plant species, particularly those growing in high-moisture environments. While traditionally classified as a saprotrophic species, under specific agricultural conditions, it acts as a facultative parasite that can invade weakened plant tissues, leading to complex pathological processes.

The disease is caused by the activity of the fungus which belongs to the Marasmiaceae family. It spreads via basidiospores that colonize organic matter and plant tissues, leading to tissue degradation. The infection type is generally categorized as a necrotic disease, causing localized or systemic decay depending on the plant's resistance and environmental conditions.

The host range of this fungus primarily includes grasses, cereal crops, and ornamental plants. It is particularly damaging in nurseries or field conditions where planting density is high. Weakened or stressed plants, such as those suffering from nutrient imbalances or improper irrigation, are the most susceptible to primary infection.

Symptoms of the disease include the formation of necrotic spots, chlorosis (yellowing), and loss of turgor in leaves and stems. As the disease progresses, the visible growth of mycelial mats and small fungal sporocarps (mushrooms) can be observed on the affected parts of the plant. This leads to the eventual collapse of infected tissues and reduced crop vitality.

Environmental conditions that favor the rapid spread of Marasmius plicatulus include:

• Prolonged periods of high humidity and rainfall;
• Poor drainage leading to waterlogged soil;
• High planting density hindering air circulation;
• Accumulation of decaying plant debris on the field surface.

To manage and prevent the spread of this pathogen, integrated pest management (IPM) is recommended. This includes removing crop residues, improving soil drainage, ensuring proper plant spacing for adequate airflow, and applying appropriate fungicidal treatments when environmental conditions are conducive to disease outbreaks. Regular scouting is critical for early detection.