Didymiaceae

The Didymiaceae family belongs to the Myxomycetes group, which are commonly known as slime molds. In agricultural environments, they can be problematic as they occasionally colonize living plant tissues, particularly in high-humidity habitats, acting as facultative pathogens that disrupt plant development.

The pathogen's lifecycle involves a mobile plasmodium stage, which moves across the substrate, followed by the formation of sporangia. These structures are often visible as crusty or powdery deposits on stems and leaves, which can be mistakenly identified as common fungal infections, complicating the diagnostic process.

Crops most susceptible to these organisms include leafy vegetables, strawberries, and ornamental plants kept in greenhouses. The damage occurs when the slime mold covers the surface of the plant, physically inhibiting gas exchange, photosynthesis, and increasing the risk of secondary infections by bacteria or true fungi.

Outbreaks of Didymiaceae are directly linked to irrigation management and environmental conditions. Warm, humid, and stagnant air conditions provide the necessary environment for the plasmodium to proliferate. Frequent overhead irrigation without adequate drying time creates a recurring risk for crop health.

To mitigate the impact of Didymiaceae, focus on environmental and cultural control strategies:

• maintain optimal spacing between plants to enhance air circulation;
• avoid overhead irrigation during late hours to prevent prolonged moisture;
• remove debris from the field or greenhouse floor to eliminate reservoirs;
• utilize appropriate contact fungicides if the colonization persists or affects crop quality.