American Potato Journal

, Volume 68, Issue 8, pp 515–524 | Cite as

Effects of inoculum density and cultivar resistance on common scab of potato and population dynamics ofStreptomyces scabies

  • Anthony P. Keinath
  • Rosemary Loria


The interaction ofStreptomyces scabies, causal agent of common scab, and its potato host was examined under scab-conducive conditions in the greenhouse. Three potato cultivars with different levels of resistance to common scab were inoculated with four levels of two rifampin-resistant strains ofS. scabies. In general, scab severity increased linearly with an increase in log10 of the inoculum, but both cultivar resistance and strain ofS. scabies affected the slope of the regression line. Rhizosphere and rhizoplane populations ofS. scabies also increased with increasing soil population. One strain ofS. scabies consistently had higher rhizosphere and rhizoplane populations than the other strain. However, rhizosphere population was not consistently related to scab severity, scab incidence, cultivar resistance, or strain virulence.

Additional Key Words

Solanum tuberosum Chippewa Superior rhizosphere rhizoplane 


Se examinó la interacción deStreptomyces scabies, el agente causal de la sarna común, y su hospedante la papa, bajo condiciones controladas de la sarna en el invernadero. Se inocularon tres cultivares de papa con diferentes niveles de resistencia a la sarna común, con cuatro niveles de dos variantes deS. scabies resistentes al rifampin. En general, la severidad de la sarna se incrementó linealmente con un incremento en el log10 del inóculo, pero tanto la resistencia del cultivar como las variantes deS. scabies afectaron la pendiente de la línea de regresión. Las poblaciones deS. scabies en la rizosfera y sobre la superficie de la raíz se incrementaron también al incrementarse la población en el suelo. Una variante deS. scabies tuvo consistentemente poblaciones más altas en la rizosfera y en la superficie de la raíz que la otra variante. Sin embargo, la población de la rizosfera no estuvo constantemente relacionada a la severidad e incidencia de la sarna, ni a la resistencia del cultivar o virulencia de la variante.


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Copyright information

© Springer 1991

Authors and Affiliations

  • Anthony P. Keinath
    • 2
  • Rosemary Loria
    • 1
  1. 1.Department of Plant PathologyCornell UniversityIthaca
  2. 2.Beltsville Agricultural Research Center-WestUSDA, ARS, Biocontrol of Plant Diseases LaboratoryBeltsville

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