Common scab

Common scab is a plant disease of root and tuber crops caused by a small number of Streptomyces species, specifically S. scabies, S. acidiscabies, S. turgidiscabies and others.

Common scab mainly affects potato (Solanum tuberosum), but can also cause disease on radish (Raphanus sativus), parsnip (Pastinaca sativa), beet (Beta vulgaris), and carrot (Daucus carota).

[1] Common scab symptoms are variable and can range from surface russeting to deep pits in root and tuber vegetables.

[3] The first known reference to common scab dates back to 1825 when it was included in John Claudius Loudon's Encyclopaedia of Agriculture.

[6] Common scab is a prevalent plant disease that is caused by the bacteria Streptomyces and it can affect a wide range of taproot crop hosts.

[citation needed] The life cycle of Streptomyces scabies or common scab in potato starts out as the pathogen overwinters in tubers left behind in the soil.

As spring comes around, some of the hyphal like growths from mycelium develop cross walls that break into asexual spores and disperse through wind, rain, or movement of soil.