Plant streptococcosis

These microorganisms are classified as Gram-positive cocci. In agroecosystems, they often act as a secondary infection, colonizing plant tissues previously weakened by other pathogens or unfavorable environmental factors.

The pathogens exhibit high adaptability to various substrates. They are capable of surviving both in the soil and on the surface of plant debris, maintaining viability for extended periods.

Infection of plants occurs through natural openings, such as stomata or hydathodes, or through mechanical damage. Bacteria rapidly multiply in the intercellular spaces, secreting specific enzymes.

The intensity of the multiplication process directly depends on the availability of nutrients within the plant sap. Compromised epidermal integrity facilitates the entry of the pathogen into the plant's vascular system.

The primary symptoms of infection include the appearance of necrotic spots, which may eventually coalesce. Often, a chlorotic halo is observed around the affected areas, caused by tissue intoxication from bacterial metabolites.

Characteristic depressions or weeping ulcers may form on stems and leaf petioles. Under high humidity conditions, an exudate may appear, resembling a whitish or yellowish film on the surface.

When the vascular system is affected, the plant exhibits rapid wilting even if soil moisture is sufficient. This occurs due to the obstruction of conducting vessels by bacterial biomass.

Internal tissues of the affected organs often change color to dark brown or black. When the stem is cut, one can observe darkening of the vascular bundles, which is a hallmark sign of bacteriosis.

In fruits, the disease manifests as localized, sunken necrotic lesions that gradually expand, eventually turning the fruit into a soft, rotting mass with an unpleasant odor.

High humidity of air and soil favors the development of the disease. Excessive moisture creates an ideal environment for the activity of bacterial microflora on the epidermal surface.

The optimal temperature range for active spread of the infection is between +20 and +28 degrees Celsius. Sudden fluctuations in temperature regimes can also weaken the plant's immune system.

The presence of insect pests is a critical factor in disease transmission. By damaging plant tissues, insects act as primary vectors, spreading the pathogen from infected plants to healthy individuals.

Failure to follow crop rotation and leaving plant residues on the field contributes to the accumulation of inoculum in the soil, increasing the risk of recurring infection in the following season.

Excessive application of nitrogen fertilizers makes plant tissues softer and more susceptible to mechanical injury, which facilitates easier colonization by bacteria.

Streptococcosis leads to significant yield losses due to premature leaf drop and inhibited photosynthesis. Affected plants show a significant lag in growth and development compared to healthy ones.

The quality of fruits and vegetable produce is severely degraded. Damaged specimens lose their marketability and are unsuitable for long-term storage or transport.

In cases of mass infection outbreaks, there is a risk of total crop failure in specific areas, resulting in substantial direct economic losses for the farming operation.

The infection can lead to reduced seed germination if seeds were harvested from infected mother plants. Thus, the disease is also transmitted via the planting material.

Contaminated fields may require costly quarantine measures and restrictions on planting susceptible crops for several years to break the infection cycle.

The primary method of protection is the use of resistant varieties and hybrids, along with seed disinfection before planting. This minimizes the risks of primary infection.

An essential step is controlling insect vectors using insecticides. Timely treatment helps to disrupt the pathways of bacterial spread across the field.

Strict crop rotation should be followed, avoiding the planting of susceptible crops in the same area for at least 3-4 years. Thorough removal and disposal of all plant residues is mandatory.

The application of copper-based preparations helps create a protective barrier on the plant surface. Regular preventative treatments with biological fungicides are also effective.

Agrotechnical measures include maintaining optimal planting density to ensure better aeration, which lowers humidity levels in the crop canopy zone.