Absidia repens

Absidia repens is a filamentous fungus belonging to the order Mucorales. While it primarily acts as a soil-dwelling saprotroph that decomposes organic matter, it is also recognized as an opportunistic plant pathogen capable of causing significant damage to agricultural crops, particularly during the early stages of development.

The fungus affects a variety of plant species, including vegetable crops and cereals. It is particularly dangerous in nursery and greenhouse environments, where it targets germinating seeds and developing root systems. Infection often occurs during the seedling stage, leading to "damping-off" or root rot, which can destroy large numbers of young plants in a short period.

The primary clinical signs of infestation include the softening and browning of root tissues, reduced vigor, and the eventual collapse of the seedling. A distinctive, fluffy, off-white to greyish mycelial mat often develops on the soil surface around the affected plant or directly on the decaying stems, serving as a diagnostic indicator of the pathogen's activity.

The spread of Absidia repens is heavily dependent on environmental conditions, specifically high humidity and moderate to warm temperatures. Soil compaction, poor drainage, and excessive irrigation are the primary drivers that facilitate the rapid colonization of host tissues. Spores can persist in the soil for extended periods, remaining dormant until favorable conditions emerge.

Effective management and protection strategies are crucial for minimizing losses. These include thorough soil sterilization in greenhouses, the use of certified pathogen-free seeds, and the application of appropriate fungicidal seed treatments. Maintaining proper aeration, preventing waterlogging, and practicing good sanitation by removing decaying plant matter are essential to suppress the pathogen and ensure healthy crop development.