Bacterial wilt of tea

The first visible symptom is the loss of turgor in young shoots and leaves, which initially appears only during the hottest hours of the day.

Subsequently, the wilting becomes irreversible. Leaf blades gradually turn yellow, starting from the edges, after which they become brown and necrotic.

Cross-sections of stems from infected plants reveal characteristic darkening of the vascular tissues, which serves as a diagnostic feature of vascular bacteriosis.

Under conditions of high humidity, bacterial exudates in the form of sticky drops containing a mass of bacterial cells may appear on the surface of infected tissues.

The final stage of the disease is the complete drying out of branches or the entire plant, leading to the death of the tea bush if emergency protection measures are not implemented.

The causative agent of this disease is the phytopathogenic bacterium Xanthomonas theicola. This microorganism belongs to the group of gram-negative rod-shaped bacteria specialized in infecting the vascular system of plants.

The disease is classified as a vascular bacteriosis, causing systemic damage to the entire shrub. Bacteria actively colonize the xylem, blocking the normal movement of water and nutrients through the vascular bundles.

The infection is characterized by high aggressiveness under favorable conditions. Bacteria multiply rapidly within plant tissues, secreting specific exoenzymes and polysaccharides that lead to vascular clogging.

The pathogen can survive in plant debris, soil, and tools used for maintenance. Dissemination occurs through raindrops, irrigation water, and insect vectors.

The biology of Xanthomonas theicola is closely linked to the plant's water regime, as the bacteria require high humidity for the initial colonization of stomata or mechanical wounds.

The development of bacterial wilt is most intense in warm and humid climates, typical of the main regions where tea is cultivated.

High relative humidity contributes to the survival of bacteria on plant surfaces and facilitates their entry into the plant interior.

The temperature optimum for Xanthomonas theicola growth is between +25°C and +30°C, coinciding with the active growth phases of tea plants.

Heavy rainfall and fog create ideal conditions for the spread of bacteria through water droplets, which are splashed onto healthy parts of the bush by wind.

Mechanical injuries resulting from careless pruning or harvesting create entry points for infection, significantly accelerating the infestation of plantations.

The main danger of this bacteriosis lies in the rapid decline of tea bush productivity and the degradation of the quality of the harvested raw material.

Massive infestation leads to a sharp reduction in healthy leaf surface area, which disrupts photosynthesis and weakens the entire plant.

The disease causes premature leaf drop, making quality harvesting impossible and reducing the yield of marketable tea leaves.

Prolonged exposure to the pathogen leads to root system exhaustion, making bushes more susceptible to other diseases and pests.

Without control, infection foci expand rapidly, potentially necessitating the removal of large sections of the plantation and resulting in significant economic losses.

The primary importance in protecting plantations lies in the use of resistant tea cultivars and hybrids adapted to local conditions.

Strict adherence to agronomic practices is essential, including correct spacing to ensure good aeration and reduce localized humidity.

Prevention includes mandatory disinfection of gardening tools after working with each plant to prevent mechanical transmission of bacteria.

The application of copper-based preparations in the early stages may slow the spread of infection, although chemical control of vascular bacteriosis is difficult.

• Removal and burning of infected bushes to contain the focus.
• Compliance with quarantine measures during the introduction of planting material.
• Control of pest populations that damage plant tissue integrity.
• Optimization of mineral nutrition to enhance plant immunity.