Detection and eradication of <i>Spongospora subterranea</i> in mini-tuber production tunnels

  • Jessica Wright Department of Microbiology and Plant Pathology, University of Pretoria
  • Alison K. Lees The James Hutton Institute, Invergowrie, Dundee
  • Jacquie E. van der Waals Department of Microbiology and Plant Pathology, University of Pretoria
Keywords: powdery scab, seed production, potato diseases, G0 tubers, obligate parasite


Powdery scab, a root and tuber disease caused by the pathogen Spongospora subterranea f.sp. subterranea (Sss), poses a major problem to potato producers worldwide because it affects potato quality. Inoculum can be seed-borne or originate from contaminated growing media or contaminated equipment. During 2006, a potato mini-tuber production facility in Ceres in the Western Cape Province of South Africa had an outbreak of powdery scab. The purpose of this study was to detect Sss in the production facility and identify the source or sources of contamination so that corrective measures could be taken to eradicate the pathogen. Swab samples were taken from numerous points in the facility in 2009 and Sss-specific primers (Sps1 and Sps2) were used in a polymerase chain reaction to detect Sss. Of 11 surfaces tested, 6 were positive for Sss. A second set of swab samples was taken after efforts were made to eradicate the pathogen through improved facility hygiene measures to determine whether these corrective measures were efficient. Corrective measures resulted in a disease-free harvest from 2009 onwards. This novel study has value for the mini-tuber industry as production tunnels can be tested for the presence of Sss and other pathogens before planting to ensure that, where suitable control measures are available, disease-free mini-tubers are produced.


1. Schulz S, Wells GJ, Baniya BK, et al. Decentralized on-farm seed potato production from pre-basic minitubers: A case study from Nepal. Exp Agr. 1998;34:487–495. >

2. Donnelly DJ, Coleman K, Coleman SE. Potato microtuber production and performance: A review. Am J Potato Res. 2003;80:103–115.

3. Badoni A, Chauhan JS. A note on micro tuber seed production of potato: Necessitate steps for Uttarakhand Hills. Report and Opinion. 2009;1(5): 9–11.

4. Ebbels DL. Incidence of tuber diseases in classified seed potatoes harvested in England and Wales, 1974–77. Plant Pathol. 1983;32:145–150.

5. Kotkas K, Rosenberg V. Disease eradication and propagation of the initial seed potato materials in Estonia. Potato Res. 1999;42:577–583. http://dx.

6. Rolot JL, Seutin H. Soilless production of potato minitubers using a hydroponic technique. Potato Res. 1999;42:457–469.

7. Struik PC. The canon of potato science: 25. Minitubers. Potato Res. 2007;50:305–308.

8. Braselton JP. Current status of the Plasmodiophorids. Crit Rev Microbiol. 1995;21:263–275., PMid:8688155

9. Cook WRI. The parasitic slime moulds. The Hong Kong Naturalist. 1932;1:29–39.

10. Christ BJ, Weidner RJ. Incidence and severity of powdery scab on potatoes in Pennsylvania. Am Potato J. 1988;65:583–588.

11. Harrison JG, Searle RJ, Williams NA. Powdery scab disease of potato – A review. Plant Pathol. 1997;46:1–25. 3059.1997.d01-214.x

12. Genet RA, Falloon RE, Braam WR, et al. Resistance to powdery scab (Spongospora subterranea) in potatoes – A key component of integrated disease management. Proceedings of the 1st International Symposium on Root and Tuber Crops: Food Down Under. Acta Hort. 2005;670:57–62.

13. Merz U, Walsh JA, Bouchek-Mechiche K, Oberhansli T, Bitterlin W. Improved immunological detection of Spongospora subterranea. Eur J Plant Pathol. 2005;111:371–379.

14. Van de Graaf P, Lees AK, Wale SJ, Duncan JM. Effect of soil inoculum level and environmental factors on potato powdery scab caused by Spongospora subterranea. Plant Pathol. 2005;54:22–28.

15. Bulman SR, Marshall JW. Detection of Spongospora subterranea in potato tuber lesions using the polymerase chain reaction. Plant Pathol. 1998;47:759–766.

16. Nakayama T, Horita M, Shimanuki T. Spongospora subterranea soil contamination and its relationship to severity of powdery scab on potatoes. J Gen Plant Pathol. 2007;73:229–234.

17. Jeger MJ, Hide GA, Van den Boogert PHJF, Termorshuizen AJ, Van Baarlen P. Pathology and control of soil-borne fungal pathogens of potato. Potato Res. 1996;39:437–469.

18. Tsror L, Aharon M, Erlich O. Survey of bacterial and fungal seedborne diseases in imported and domestic potato seed tubers. Phytoparasitica. 1999;27(3):215–226.

19. Muro J, Diaz V, Goni JL, Lamsfus C. Comparison of hydroponic culture and culture in a peat/sand mixture and the influence of nutrient solution and plant density on seed potato yields. Potato Res. 1997;40:431–438.

20. Merz U. Epidemiological aspects of powdery scab of potatoes caused by Spongospora subterranea. Paper presented at: Second Symposium of the International Working Group on Plant Viruses with Fungal Vectors; 1993 July 25–27; Montreal, Canada. Denver, CO: American Society of Sugar Beet Technologists; 1993. p. 103–106.

21. Iftikhar S, Ahmad I, Rattu A. Presence of Spongospora subterranea in soils of potato production areas in Gilgit and Hunza valley of Pakistan. Pak J Biol Sci. 2000;3:848–849.

22. Falloon RE. Control of powdery scab of potato: Towards integrated disease management. Am J Potato Res. 2008;85:253–260.

23. Van de Graaf P, Lees AK, Cullen DW, Duncan JM. Detection and quantification of Spongospora subterranea in soil, water and plant tissue samples using real-time PCR. Eur J Plant Pathol. 2003;109:589–597.

24. McCartney HA, Foster SJ, Fraaije BA, Ward E. Molecular diagnostics for fungal plant pathogens. Pest Manag Sci. 2003;59:129–142., PMid:12587866

25. Qu X, Kavanagh JA, Egan D, Christ BJ. Detection and quantification of Spongospora subterranea f. sp. subterranea by PCR in host tissue and naturally infested soils. Am J Potato Res. 2006;83:21–30.

26. Hanafi A. The sanitary quality of substrates: A key component in IPP and its potential role in the spread of invasive species of pests and diseases of greenhouse crops. Acta Hort. 2003;608:21–24.

27. Merz U, Martinez V, Schwarzel R. The potential for the rapid screening of potato cultivars (Solanum tuberosum) for resistance to powdery scab (Spongospora subterranea) using a laboratory bioassay. Eur J Plant Pathol. 2004;110:71–77.

28. Merz U. Powdery scab of potato – Occurrence, life cycle and epidemiology. Am J Potato Res. 2008;85:241–246.

29. Nitzan N, Boydston R, Batchelor D, et al. Hairy nightshade is an alternative host of Spongospora subterranea, the potato powdery scab pathogen. Am J Potato Res. 2009;86:297–303.