American Journal of Potato Research

, Volume 86, Issue 3, pp 183–187 | Cite as

Evidence that the Zebra Chip Disease and the Putative Causal Agent Can be Maintained in Potatoes by Grafting and In Vitro

  • James M. CrosslinEmail author
  • Joseph E. Munyaneza


In the last several years, a disorder of chipping potatoes that causes internal browning of raw tubers and very dark chip color when the tubers are fried has been described from the southwestern United States. The discoloration often shows as rays or stripes and the common name “zebra chip” (ZC) has been used to describe the disorder. Foliar symptoms include chlorosis, purpling of shoot tips, and leaf scorch. Aerial tubers are sometimes produced on diseased plants. The disease has been associated with the potato psyllid, Bactericera cockerelli, but a suspected pathogen that may be associated with the ZC disorder has only very recently been described. In our efforts to identify the causal agent we have been maintaining the disease in the greenhouse by tip grafting symptomatic potato shoots onto healthy plants of several commercially important cultivars of potatoes, including Atlantic, Russet Burbank, and Russet Norkotah. Most of the grafted plants subsequently developed ZC symptoms. Many of the grafted plants produced tubers with symptoms typical of the disease. In cultivar Atlantic, 104 of 138 grafted plants developed foliar symptoms of ZC and 72 of the grafted plants produced ZC-symptomatic daughter tubers. Grafted plants without foliar symptoms did not produce symptomatic tubers. Herein we report the results of these grafting experiments and describe the symptoms produced in grafted plants and daughter tubers. We have also maintained the disease by placing surface-sterilized symptomatic shoots onto growth medium in vitro. In addition, the putative ZC pathogen, a new Candidatus Liberibacter spp., has been detected in symptomatic grafted plants, symptomatic in vitro plants, and potato psyllids by PCR.


Potato diseases Zebra chip Potato psyllid Bactericera cockerelli 


En los últimos años se ha descrito en el sudoeste de EE.UU. un desorden en papas para fritura que causa el oscurecimiento interno de los tubérculos crudos y un color completamente oscuro de las hojuelas. La decoloración se muestra a menudo como rayas o franjas y se ha usado el nombre común de “hojuelas zebra (ZC)” para describirla. Los síntomas foliares incluyen clorosis, enrojecimiento de la punta de los brotes y chamuscado de las hojas. A veces se producen tubérculos aéreos en las plantas enfermas. La enfermedad ha sido asociada con el psílido de la papa Bactericera cockerelli, pero recientemente se ha descrito un patógeno que se sospecha esté asociado con el ZC. En el esfuerzo de identificar el agente causal hemos mantenido la enfermedad en el invernadero injertando los retoños de plantas sintomáticas a plantas sanas de varios cultivares de papa comercialmente importantes, incluyendo Atlantic, Russet Burbank y Russet Norkotah. La mayoría de las plantas injertadas desarrollaron síntomas de ZC. Muchas de las plantas injertadas produjeron tubérculos con síntomas típicos de la enfermedad. En el cultivar Atlantic, 104 de 138 de plantas injertadas desarrollaron síntomas foliares de ZC y 72 de las plantas injertadas produjeron tubérculos hijos sintomáticos. Plantas injertadas sin síntomas foliares no produjeron tubérculos sintomáticos. Por lo tanto informamos los resultados de estos experimentos y describimos los síntomas producidos en las plantas injertadas y los tubérculos hijos. Hemos mantenido también la enfermedad poniendo brotes sintomáticos esterilizados superficialmente en medio de crecimiento in vitro. Además, el supuesto patógeno de ZC, un nuevo Candidatus Liberibacter spp., ha sido detectado por PCR en las plantas sintomáticas injertadas, plantas sintomáticas in vitro y los psílidos de papa.


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Copyright information

© Potato Association of America 2009

Authors and Affiliations

  1. 1.Vegetable and Forage Crops Research UnitUSDA-ARSProsserUSA
  2. 2.Yakima Agricultural Research LaboratoryUSDA-ARSWapatoUSA

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