Cylindrocarpon rot

This pathogen is a soil-inhabiting fungus capable of persisting in the substrate for long periods via chlamydospores or mycelium within decaying plant debris.

The fungus is characterized by the production of microconidia, macroconidia, and chlamydospores, which allow it to survive in harsh environmental conditions.

It exhibits high ecological plasticity, enabling it to colonize the root systems of various plant species effectively under high soil moisture conditions.

Mycological identification is performed by isolating the pathogen from infected tissues onto culture media, where it forms distinct colonies with abundant spore production.

Host plants include various ornamentals such as lilies, daffodils, and tulips, as well as agricultural crops like ginseng, grapevines, and fruit tree seedlings.

The pathogen primarily attacks the root system and the root collar, leading to progressive necrotic lesions and the complete destruction of plant tissues.

In ginseng cultivation, this fungus is a major cause of massive plantation dieback, often manifesting as a specific type of root rot known as rusty root.

In bulbous plants, the infection destroys the basal plate, rendering the planting material unsuitable for further growth or long-term storage.

Nursery seedlings are particularly vulnerable, suffering from root decay that results in stunted growth, leaf chlorosis, and eventual plant mortality.

The disease development is most intense during periods of high soil humidity and moderate temperatures, typically occurring in the spring and autumn seasons.

Primary infection occurs through micro-wounds in the root system caused by transplanting, soil-dwelling insect damage, or waterlogged soil conditions.

The life cycle includes a dormant stage during unfavorable conditions and an active replication stage when a susceptible host is available.

Conidia are spread through splashing water, contaminated soil, agricultural tools, or the use of infected planting stock.

In greenhouse environments, the infection pressure can remain high throughout the year if irrigation and soil aeration are not properly managed.

The first symptoms of infection include a general decline in plant vigor, leaf yellowing, reduced growth rates, and the deformation of young shoots.

Inspection of the root system reveals brown or tan lesions that gradually coalesce, eventually covering large portions of the root tissue.

Roots become soft, watery, and eventually decay into a mushy mass, which can be easily detected when the plant is gently pulled from the soil.

Under high humidity conditions, a white or pinkish mycelial mat may develop on the affected surfaces, representing clusters of fungal spores.

In advanced stages of bulb infections, the basal plate is completely destroyed, and inner scales may appear translucent or discolored.

The primary control strategy is the implementation of crop rotation, excluding susceptible crops from infested fields for at least 5–7 years.

Improving soil drainage is a critical agronomic practice, as waterlogging is the main factor promoting the development of Cylindrocarpon rot.

Biological fungicides based on Trichoderma strains can help suppress the pathogen in the soil through mycoparasitism and niche competition.

• Treating planting material with appropriate fungicides.
• Prompt removal and destruction of severely infected plants.
• Using certified disease-free propagation material.
• Sterilizing soil mixes before planting susceptible crops.

Chemical fungicides are effective when applied at early stages, provided that application protocols are strictly followed and active ingredients are rotated to prevent resistance.