Streptococcosis of plants

Streptococcosis is a type of bacterial infection affecting various agricultural and horticultural crops, caused by bacteria belonging to the Streptococcaceae family. Although often overlooked in favor of more common bacterial pathogens, these microorganisms can cause significant tissue decay and metabolic disorders within the host plant, leading to stunted growth or total loss of yield.

The primary mode of entry for these bacteria is through mechanical injuries, wounds left by pruning tools, or naturally occurring stomata during periods of high humidity. Once inside, the bacteria proliferate rapidly, producing enzymes that degrade the plant's cell walls, which leads to the formation of soft rot lesions and systemic tissue death.

Symptoms of the infection typically include localized yellowing (chlorosis) followed by rapid wilting of affected tissues. As the infection progresses, the tissues may become dark, water-soaked, and soft. In advanced stages, a foul odor may be present due to the secondary saprophytic organisms colonizing the dead plant tissue.

Environmental conditions play a key role in the spread of the disease. Warm, humid environments promote bacterial growth and movement through moisture films on leaf surfaces. Poor air circulation in greenhouse environments or dense plant spacing facilitates the rapid transition of the pathogen from infected to healthy plants via water splashing and contaminated hands or tools.

Management of this bacterial disease requires a multifaceted approach focused on prevention. Important practices include:

• Regular sterilization of agricultural equipment and tools;
• maintaining optimal humidity levels in greenhouse structures;
• implementing crop rotation schedules to break the disease cycle;
• using certified disease-free planting material.