Streptomycosis

Streptomycosis is a plant disease caused by the soil-inhabiting actinomycetes known as Streptomyces albus. These bacteria naturally reside in the soil profile but can transition into parasitic pathogens when environmental conditions favor their proliferation and host plant susceptibility.

The primary crop affected by this pathogen is the potato, where it manifests as common scab. However, the disease is not restricted to potatoes; it can also affect a variety of other root crops such as carrots, radishes, and beets, leading to significant economic losses for farmers.

Symptoms of the disease are characterized by surface lesions, scabs, and corky outgrowths on the skin of tubers or roots. While these injuries often do not affect the internal quality of the vegetable, they severely impact marketability and increase susceptibility to secondary storage rots.

The development of Streptomyces albus is heavily influenced by soil factors. The pathogen thrives in neutral to alkaline soils, particularly during periods of high temperature and low soil moisture during the tuber initiation stage. Excessive application of fresh manure or lime often exacerbates the disease prevalence.

Effective management strategies include the use of disease-free planting material and the selection of resistant cultivars. Cultural practices such as crop rotation, maintaining adequate soil moisture during the critical tuberization phase, and using acidic fertilizers can significantly suppress the pathogen and protect the harvest.