Cylindrocladiella

The primary signs of infection are systemic rots affecting the root system and the root collar of plants. In young seedlings, lodging is often observed due to the destruction of tissues at the base of the stem.

The foliage of affected specimens gradually turns yellow, loses turgor, and subsequently browns and falls off. Upon detailed inspection of the roots, one can notice dark necrotic spots that eventually merge, covering the entire root system.

In the early stages of infection under high humidity, a barely visible whitish or creamy mycelial mat may appear on the surface of affected areas. This indicates active sporulation of the pathogen.

In ornamental and forest nurseries, the disease often manifests in patches where seedlings look stunted compared to healthy ones. Ultimately, the complete death of the root system and the whole plant occurs.

Internal root tissues, when sectioned, often exhibit characteristic browning of the vascular ring, which is a secondary sign of fungal hyphae penetration into the plant's conductive bundles.

The disease is caused by imperfect fungi of the genus Cylindrocladiella (family Nectriaceae). These are widely distributed soil-borne pathogens capable of surviving in the substrate for long periods as mycelium or chlamydospores.

These microorganisms are opportunistic parasites that frequently become active under environmental stress. They are capable of infecting both herbaceous plants and woody crops in nursery settings.

The taxonomy of the fungus is complex, and many Cylindrocladiella species were previously misclassified as representatives of related genera, such as Cylindrocladium. Accurate identification requires laboratory analysis of morphological spore and colony characteristics.

The pathogen has the ability to rapidly colonize organic matter in the soil, making it highly resistant to adverse conditions. It spreads easily through contaminated planting material and nursery equipment.

The biological cycle of the fungus includes both a saprotrophic stage and an active phase of invasion into the vascular system or roots of host plants, ensuring its high competitiveness in agroecosystems.

The key factor for fungal development is excessive soil moisture and poor substrate aeration. In waterlogged environments, the pathogen spreads as rapidly as possible through the soil solution.

A temperature range of 20–25°C is most favorable for the active growth of Cylindrocladiella mycelium. Under such conditions, the incubation period shortens and the intensity of infection increases.

Violation of agricultural practices, such as overcrowding of crops and poor air circulation in greenhouses, creates ideal conditions for the mass spread of the infection from sick to healthy plants.

The use of non-disinfected substrate or contaminated peat often becomes the primary source of the pathogen's introduction into protected environments, where the disease can develop year-round.

Stressed plants experiencing nutrient deficiencies or mechanical damage during transplanting become the most vulnerable to the introduction of fungal spores into their tissues.

The damage caused by the disease consists of premature death of young seedlings, leading to significant economic losses in nursery production. The disease can destroy up to 80% of planting material in favorable years.

In addition to direct mortality, Cylindrocladiella causes hidden plant degradation, leading to stunted growth, loss of aesthetic and commercial value, and unsuitability for sale or professional landscaping use.

The pathogen can harm many valuable crops, including eucalyptus, various conifers, and floral species. The wide host range makes the disease difficult to control under intensive farming conditions.

The accumulation of infectious inoculum in the soil makes it impossible to use infected plots for sensitive crops for several seasons without deep fumigation or soil treatment.

Systemic root infection disrupts water and mineral uptake, making plants extremely susceptible to other soil pathogens and intensifying the overall negative impact on the crop.

The primary protective measure is compliance with sanitary protocols: using only sterile substrates and healthy, certified planting material that has undergone prior inspection.

It is important to establish a proper irrigation schedule that prevents stagnant water in pots and beds. Drainage systems must ensure rapid water removal to prevent the development of root rot.

Chemical control methods include soil drenching with systemic fungicides active against oomycetes and other soil-borne fungi. Repeated treatments are performed at 10–14 day intervals according to regulations.

Biological products based on Trichoderma spp. show high efficacy in suppressing Cylindrocladiella populations in the rhizosphere by acting as natural antagonists to the pathogen.

• Regular disinfection of tools and equipment.
• Removal and destruction of all infected plants along with the surrounding soil.
• Maintaining optimal plant density to improve ventilation.
• Adjusting soil pH to values unfavorable for fungal growth.