Bacterial root rot

The first noticeable sign of the disease is a sharp inhibition of plant growth and leaf chlorosis, often mistaken for nutritional deficiencies.

Examination of the root system reveals characteristic browning and softening of the tissues. The roots turn brown or dark brown and produce a distinct foul odor.

A slimy coating is often observed on the affected roots, which is a direct consequence of active bacterial proliferation in the infection zone.

In chickpeas, symptoms often manifest as wilting of shoot tips during the day, followed by complete plant desiccation as the rot progresses.

Severe infection of the root collar causes the plant to be easily pulled from the soil, as most root hairs are completely destroyed.

The causative agent of this disease is the phytopathogenic bacterium Pseudomonas radiciperda. This microorganism is a Gram-negative rod capable of surviving for long periods in soil and on plant debris.

The bacterium actively colonizes the root system, entering the plant tissues through micro-cracks or natural damage sites. During its life cycle, the pathogen releases specific enzymes that break down root cell walls.

Unlike fungal infections, bacterial rots often develop latently, spreading rapidly through the plant's vascular system when conditions favor the pathogen.

In addition to direct damage, Pseudomonas radiciperda facilitates secondary tissue infection, weakening the plant's immunity against other soil-borne parasites.

In the soil profile, the bacterium is able to survive in the rhizosphere of a wide range of plants, making crop rotation a key tool in controlling this pathogen population.

Bacterial root rot development is most intense in heavy, waterlogged soils where oxygen deficiency occurs.

The optimal temperature range for the active multiplication of Pseudomonas radiciperda is between +20°C and +28°C, which coincides with the active growth phases of many legumes.

The presence of large amounts of undecomposed plant residues in the soil creates a favorable substrate for the accumulation of the infection in the agro-ecosystem.

Damage to the root system by pests, such as nematodes or soil-dwelling insects, significantly accelerates the penetration of bacteria into deep root tissues.

Excessive nitrogen fertilizer application, which promotes rapid vegetative growth, often reduces root resistance to bacterial infection.

The main damage consists of mass seedling death, leading to thinning of stands and a significant reduction in plant density in the field.

Plants that survive the infection lag significantly in development, have poorly developed root systems, and are unable to form a full crop of beans.

In cases of epiphytotic disease development, yield losses for legumes, including chickpeas, can reach 30–50% or more, depending on soil moisture intensity.

Reduction in grain quality is also a negative consequence of the disease, as impaired plant nutrition affects the thousand-kernel weight and grain filling.

The accumulation of the pathogen in the soil makes it impossible to grow susceptible crops for several seasons without implementing specific phytosanitary measures.

The primary protection measure is strict adherence to crop rotation, preventing the return of susceptible crops to the same area for at least 4–5 years.

Using high-quality seed treated with fungicides and bactericides helps protect seedlings during the early critical stages of development.

Agricultural practices aimed at improving soil aeration, such as loosening and proper cultivation, prevent the creation of anaerobic conditions suitable for bacteria.

• Applying balanced doses of potassium fertilizers to increase overall plant resistance.
• Timely destruction of weeds that can act as infection reservoirs.
• Application of biological products based on antagonistic strains of Bacillus subtilis.

In case of detected infection outbreaks, agricultural equipment must be disinfected to prevent mechanical transfer of bacteria between fields.