Impact of high soil pH on potato yields and grade losses to common scab

2002 ◽  
Vol 82 (3) ◽  
pp. 583-586 ◽  
Author(s):  
D. Waterer
Keyword(s):  
Solanum Tuberosum ◽  
Soil Ph ◽  
Common Scab ◽  
Streptomyces Scabies ◽  
Alkaline Soils ◽  
Multiple Cropping ◽  
Ph Change ◽  
Potato Common Scab ◽  
Potato Yields ◽  
Cropping Seasons

The influence of soil pH on yields and grade-out due to tuber damage by common scab (Streptomyces scabies) was evaluated over multiple cropping seasons for potato (Solanum tuberosum) grown on land heavily infested with S. scabies. Soils with a native pH of 8.0 were adjusted to pH 7.0 to 9.0 using elemental sulfur as an acidulant and calcitic lime as the liming agent. There was little change in total tuber yields over this pH range, but the incidence and severity of scab lesions declined as the pH increased above 8.5. Marketable yields after grade-out to scab were highest at pH 9.0. This study demonstrates that in alkaline soils losses due to potato common scab may be managed by adjusting the soil pH to a point unfavorable to the scab organism. The economics of this type of pH change and its impact on subsequent crops need to be considered. Key words: Common scab, Streptomyces scabies, Solanum tuberosum, liming

Management of common scab of potato using planting and harvest dates

2002 ◽  
Vol 82 (1) ◽  
pp. 185-189 ◽  
Author(s):  
D. Waterer
Keyword(s):  
Solanum Tuberosum ◽  
Disease Management ◽  
Common Scab ◽  
Potato Scab ◽  
Streptomyces Species ◽  
Early Planting ◽  
Streptomyces Spp ◽  
Harvest Dates ◽  
Tuber Grade ◽  
Cropping Seasons

The influences of planting and harvest dates on yields and grade-out due to tuber damage by common scab (Streptomyces spp.) were evaluated over three cropping seasons using two cultivars of potato (Solanum tuberosum) grown on land heavily infested with pathogenic Streptomyces species. Early planting and delaying the harvest enhanced yields in both cultivars, but also increased tuber grade-out due to excessive levels of scab. Delaying the harvest reduced marketable yields more than did early planting. The longer harvest was delayed after top-kill, the greater was the grade out due to scab. Increased losses to scab exceeded any increase in tuber yields obtained by delaying harvest. This study demonstrates that common scab of potato may be managed by minimizing the period the crop is in the ground, but that this method of disease management is achieved at the expense of yields. Early planting coupled with timely harvesting after kill-down of the tops appears to be an effective compromise between the objectives of maximizing yields while avoiding excessive grade-out due to common scab. Key words: Potato scab, Streptomyces scabies, Solanum tuberosum, agronomy

scholarly journals Positive and Negative Regulation of the Virulence-Associated Coronafacoyl Phytotoxin in the Potato Common Scab Pathogen Streptomyces scabies

2019 ◽  
Vol 32 (10) ◽  
pp. 1348-1359 ◽  
Author(s):  
Zhenlong Cheng ◽  
Luke Bown ◽  
Brandon Piercey ◽  
Dawn R.D. Bignell
Keyword(s):  
Pathogenic Bacteria ◽  
Common Scab ◽  
Regulatory Gene ◽  
Biosynthetic Gene Cluster ◽  
Streptomyces Scabies ◽  
Structural Genes ◽  
Disease Symptoms ◽  
Family Protein ◽  
Potato Common Scab ◽  
Important Virulence Factor

The potato common scab pathogen Streptomyces scabies produces N-coronafacoyl-l-isoleucine (CFA-Ile), which is a member of the coronafacoyl family of phytotoxins that are synthesized by multiple plant pathogenic bacteria. The CFA-Ile biosynthetic gene cluster contains a regulatory gene, cfaR, which directly controls the expression of the phytotoxin structural genes. In addition, a gene designated orf1 encodes a predicted ThiF family protein and is cotranscribed with cfaR, suggesting that it also plays a role in the regulation of CFA-Ile production. In this study, we demonstrated that CfaR is an essential activator of coronafacoyl phytotoxin production, while ORF1 is dispensable for phytotoxin production and may function as a helper protein for CfaR. We also showed that CFA-Ile inhibits the ability of CfaR to bind to the promoter region driving expression of the phytotoxin biosynthetic genes and that elevated CFA-Ile production by overexpression of both cfaR and orf1 in S. scabies increases the severity of disease symptoms induced by the pathogen during colonization of potato tuber tissue. Overall, our study reveals novel insights into the regulatory mechanisms controlling CFA-Ile production in S. scabies and it provides further evidence that CFA-Ile is an important virulence factor for this organism.

scholarly journals First Report of Streptomyces scabies Causing Potato Common Scab in Punjab, Pakistan

Plant Disease ◽  
2017 ◽  
Vol 101 (2) ◽  
pp. 378 ◽  
Author(s):  
A. Sarwar ◽  
Z. Latif ◽  
C. R. Osorio ◽  
C. Cabaleiro
Keyword(s):  
Common Scab ◽  
Streptomyces Scabies ◽  
First Report ◽  
Potato Common Scab

Irrigation as a Practical Means to Control Potato Common Scab (Streptomyces scabies)

1971 ◽  
Vol 20 (4) ◽  
pp. 157-163 ◽  
Author(s):  
D. H. Lapwood ◽  
L. W. Wellings ◽  
J. H. Hawkins
Keyword(s):  
Common Scab ◽  
Streptomyces Scabies ◽  
Potato Common Scab
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