Rhizoctonia Stem Canker

Severe stem cankers can lead to production of tubers on aerial plant parts.

Causal Agent:

Rhizoctonia solani


Pathogen of potatoes everywhere. Infection of young plants is encouraged by cool soil. Rhizoctonia is easily and commonly moved on seed tubers. Disease in the field is initiated by both soil-borne and seed-borne inoculum. Infected sprouts can be killed, leading to delayed emergence and weak plants. Triggers for formation of sclerotia, called black scurf, on daughter tubers are not well-understood.


  1. Minimize seed-borne inoculum by purchasing seed with minimal black scurf.
  2. Reduce sprout infection by minimizing the time from planting to emergence.
  3. Crop rotation will help reduce the populations of Rhizoctonia solani that are specific to potato.
  4. Certain fungicides applied to seed pieces or in furrow at planting can reduce stem canker and black scurf caused by Rhizoctonia.

Further Reading:

Pacific Northwest Pest Management Handbooks

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Insects, Diseases, Nematodes, & Beneficial Organisms

Find out more information about insects, diseases, nematodes, and beneficial organisms for Potatoes.

About The Northwest Potato Research Consortium

In February 2012 the state potato commissions in Washington, Idaho, and Oregon officially launched a new cooperative effort in research. The aim of this initiative is to increase cooperation and efficiency of the research programs funded by the three potato commissions that total about $1.5 million annually. It will also work toward comprehensive research results reporting process that aims to get useful information to the growers and industry members who need it. This website is a big part of that effort. Research results, integrated pest management guidance, and production information of many kinds will be presented here. For feedback or suggestions on this site, please contact Raina Spence, Manager of the Consortium.

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