Cylindrocarpon root rot

Above-ground, affected plants exhibit stunted growth, yellowing (chlorosis) of the foliage, and premature wilting, often starting from the lower leaves.

Inspection of the roots reveals deep pitting and rotting of the tissue, eventually leading to the total destruction of the plant's root system.

In high-humidity environments, a white or pinkish mycelial mat may become visible on the surface of the infected roots or at the base of the stem.

Seedlings and young plants often collapse at the root crown, leading to sudden plant death and significant gaps in the crop stands.

The disease is caused by the soil-borne fungus Ilyonectria destructans (formerly known as Cylindrocarpon destructans).

The pathogen is highly persistent due to the formation of chlamydospores, which allow the fungus to survive in the soil for several years without a host.

It has a broad host range, causing severe economic damage to ginseng, grapes, fruit trees, and various ornamental species.

Infection spreads easily through infested soil, contaminated planting equipment, movement of water, and infected nursery stock.

The fungus functions as both a parasite on living plant roots and a saprophyte on organic matter in the soil, making it extremely difficult to eradicate.

The development of Cylindrocarpon root rot is favored by high soil moisture and moderate temperatures, typically between 15°C and 22°C.

Poorly drained soils or excessive irrigation create waterlogged conditions that trigger spore germination and infection of the root zone.

Mechanical damage to roots, caused by pests or cultivation practices, provides easy entry points for the fungal mycelium to penetrate plant tissues.

Acidic soil conditions (low pH) are known to exacerbate the disease, as the pathogen thrives in these environments.

High planting density reduces air circulation, leading to stagnant microclimates that increase the risk of disease transmission between plants.

This disease is a major threat to the ginseng industry, where it can cause devastating losses, sometimes reaching nearly 100% of the harvest.

In fruit nurseries, it causes severe damage to young transplants, leading to high mortality rates and increased production costs.

Infected crops show significantly reduced vigor and yield, and they are much more susceptible to secondary attacks by other soil pathogens.

The quality of the harvested product is compromised, making it unsuitable for market, as decay continues to progress during transport and storage.

The long-term presence of Ilyonectria destructans in the soil forces producers to abandon fields or use expensive soil sterilization techniques.

The first line of defense is the rigorous selection of clean, disease-free planting material to prevent introducing the pathogen to new areas.

Crop rotation practices should be strictly followed, avoiding the cultivation of susceptible plants on infested land for at least 5 to 7 years.

Improving soil drainage and adjusting pH through liming can create an environment that suppresses the growth and activity of the fungus.

Chemical control involving seed treatments and soil drenching with appropriate fungicides is essential for managing the disease in intensive systems.

• Sanitizing tools and machinery before moving between plots.
• Removing and destroying all symptomatic plants and root debris.
• Promoting plant health through balanced fertilization and stress reduction.