Ceratorhiza hydrophila

The first visual symptoms of the disease appear as darkening of the root collar and roots. Tissues turn brown or dark, becoming soft and water-soaked.

Affected areas often show a white or grayish web-like growth, which is the vegetative body of the fungus. This mycelium is particularly noticeable under conditions of high humidity.

Infected plants show stunted growth; leaves begin to yellow and wilt prematurely, even with sufficient watering. This occurs due to damage to the vascular system of the roots.

In cases of severe infection, the root system is almost completely destroyed, leading to plant death. Damping-off of seedlings is a common symptom due to the rotting of stem tissues at the soil surface.

Upon inspection of the root system, one can often observe a characteristic constriction at the root collar, a typical sign of rhizoctonia-like infections.

The causal agent of the disease is the microscopic imperfect fungus Ceratorhiza hydrophila (formerly classified within the Rhizoctonia group). This is a soil-borne pathogen that persists in the substrate as mycelium or sclerotia.

This fungus belongs to a group of rhizoctonia-like pathogens known for their strong saprotrophic ability. It effectively colonizes organic debris in the soil, allowing it to survive for long periods outside of host plant roots.

The biology of the pathogen is closely tied to soil water status. The fungus produces enzymes that degrade plant cell walls, facilitating the invasion of root and stem tissues.

Ceratorhiza hydrophila is characterized by a wide host range, frequently occurring on various plant families, especially those grown under high humidity or in hydroponic systems.

The mycelium grows actively upon contact with the root system, forming dense networks. During its life cycle, the pathogen releases toxins that contribute to the general inhibition of plant physiological processes.

The primary factor triggering the disease is excessive soil or substrate moisture. The fungus thrives in anaerobic or waterlogged conditions, which is reflected in its species name (hydrophila).

The optimal temperature range for active mycelial spread is typically within moderate values, though the pathogen can remain active across a wide temperature spectrum.

Poor aeration of the root system, caused by soil compaction or overwatering, significantly accelerates the infection process in healthy tissues.

The use of non-disinfected tools, contaminated seeds, or recycled substrate contributes to the rapid spread of the pathogen throughout a field or greenhouse facility.

Failure to rotate crops and the accumulation of plant debris in the topsoil create a favorable nutrient source for the build-up of Ceratorhiza hydrophila inoculum.

This disease causes significant economic losses, resulting in massive seedling mortality and a substantial decline in the marketability of mature produce.

The infection leads to thin, uneven stands, requiring costly replanting and increasing overall production expenses.

Damage to the root system sharply reduces plant productivity, even if plants do not perish completely. Yield decreases, and the quality of fruits and vegetables declines due to disrupted metabolic processes.

In greenhouses and hydroponic systems, the pathogen can spread through the entire system within a short time, potentially leading to total crop failure.

Long-term persistence of the pathogen in the soil complicates the cultivation of susceptible crops for several years without the use of aggressive sterilization methods.

The foundation of management is adherence to agronomic practices aimed at preventing water stagnation and ensuring adequate soil aeration.

Quality disinfection of seed material before sowing is essential, utilizing modern fungicides or biological control agents.

Implementing effective crop rotation is recommended to avoid long-term cultivation of related crops in the same area, combined with the timely removal of plant debris.

The use of biological fungicides based on Trichoderma helps suppress the pathogen in the soil by creating a competitive environment for beneficial microorganisms.

• Use of resistant varieties.
• Regular greenhouse ventilation.
• Monitoring substrate moisture levels.
• Disinfection of tools and equipment.
• Isolation of infected plants.