Streptomycosis

Streptomycosis is a bacterial plant disease caused by actinomycetes of the species Streptomyces vendargensis. This soil-borne pathogen is widely known for causing scab, which significantly impacts the quality and marketability of root crops and tubers in various agricultural systems.

The disease primarily affects economically important crops such as potatoes, carrots, radishes, and beets. The bacteria survive in the soil as saprophytes, feeding on decomposing organic matter, which allows the pathogen to persist in fields for many years, making eradication extremely challenging for farmers.

Symptoms of the infection manifest as raised scabs, shallow pits, or deep corky lesions on the skin of the tubers or roots. These blemishes not only ruin the product's aesthetic value but also increase susceptibility to storage rot, leading to substantial economic losses post-harvest and during long-term storage.

The development of Streptomyces vendargensis is strongly influenced by soil conditions, particularly pH levels. The disease thrives in neutral to alkaline soils (pH 6.5–7.5) and is exacerbated by periods of low moisture during the tuber initiation stage, which creates a favorable environment for bacterial colonization of the root zone.

Effective management and prevention strategies include:

• Implementation of long-term crop rotation schemes.
• Application of physiological acidifying fertilizers to lower soil pH.
• Selection of resistant plant cultivars.
• Maintenance of adequate soil moisture during critical development stages.
• Use of clean, certified planting material to avoid introducing the pathogen into healthy soil.