Algeria tombusvirus

A characteristic sign is a mosaic pattern of coloration, where healthy green tissues alternate with patches of yellowing of varying intensity.

In some cases, leaf deformation occurs, manifesting as curling, crinkling, or a reduction in the surface area of the leaf blade compared to the norm.

Infected plants significantly lag behind in growth compared to healthy specimens, which is especially noticeable in the early stages of vegetative development.

During the generative phase, shedding of flower buds and the formation of underdeveloped, deformed fruits are possible, significantly reducing the marketable value of the harvest.

The causative agent of the disease is Tombusvirus algeriaense, a virus belonging to the genus Tombusvirus within the family Tombusviridae.

Viral particles have an icosahedral shape, with a diameter of about 30 nanometers, and the genome consists of a positive-sense single-stranded RNA.

This pathogen exhibits high stability in the external environment, which facilitates its survival in soil substrates and plant debris over long periods.

The virus is characterized by the absence of specific insect vectors in the classic sense; transmission occurs more frequently through mechanical contact or via contaminated soil.

The biology of the pathogen allows it to quickly adapt to conditions in protected growing environments, where high plant density promotes rapid spread.

The development of the virus is favored by optimal temperature conditions in the range of 20–25 degrees Celsius, which accelerate RNA replication in plant tissues.

The primary mode of infection is the contact of root systems with infested soil, where the virus can persist in stable forms.

Mechanical transmission of the pathogen through tools, work clothing, or during agricultural operations such as pruning plays a crucial role in its spread.

High soil moisture and waterlogging create favorable conditions for the survival of the virus in the root zone and subsequent penetration into the vascular system.

The lack of phytosanitary control over substrate and seed material quality leads to rapid epiphytotics in greenhouse farming conditions.

The harmfulness of Algeria tombusvirus lies in the systemic nature of the infection, which affects all vital functions of the plant.

Significant yield losses occur due to the disruption of photosynthetic processes, leading to plant exhaustion and reduced biomass accumulation.

Product quality decreases due to changes in the biochemical composition of fruits, loss of firmness, and poor visual appearance, rendering them unsuitable for sale.

Systemic infection leads to premature plant senescence, which shortens the active fruiting period and reduces the overall profitability of production.

In cases of severe outbreaks, total loss of the marketable harvest is possible, requiring radical measures to eradicate infection sources within the growing area.

The primary control measure is strict adherence to greenhouse hygiene, including the disinfection of tools, containers, and work surfaces using sodium hypochlorite solutions.

Regular monitoring of crops is necessary, and suspected plants must be immediately removed along with their root balls to prevent secondary spread.

The use of certified healthy seed material is recommended, and in cases of soil-based cultivation, heat or chemical sterilization of the soil before planting is essential.

The use of resistant cultivars and hybrids is the most economically viable prevention method, limiting the virus's ability to multiply.

• Disinfection of personnel hands and clothing when moving between greenhouse sections.
• Regular cleaning and disinfection of irrigation systems and drainage channels.
• Control of soil-borne pests that can facilitate the spread of the infection through damaged roots.