Crop & Pest Report

Accessibility


| Share

Managing Rhizoctonia Root Rot of Sugarbeet (06/02/16)

The fungus Rhizoctonia solani causes Rhizoctonia damping-off, crown and root rot of sugarbeet in North Dakota and Minnesota.

Managing Rhizoctonia Root Rot of Sugarbeet

The fungus Rhizoctonia solani causes Rhizoctonia damping-off, crown and root rot of sugarbeet in North Dakota and Minnesota.  Rhizoctonia is listed as the most important production problem for sugarbeet growers since 2009. Growers are using more Rhizoctonia tolerant varieties coupled with seed treatments to protect from damping-off. The most widely used seed treatment is Kabina, which gives about four to five weeks of protection. It is recommended that growers use a post emergent fungicide to protect plants from crown rot and root rot. Crown rot is initiated when soil with inoculum is thrown into the crown at cultivation, and during heavy rainfall or flooding. Crown rot has not been a major issue with the adoption of Roundup Ready sugarbeet and the concurrent reduction or non-use of cultivation for weed control. Root rot has been a major issue for growers. Fields with no fungicide seed treatment for control of Rhizoctonia should be treated before the daily average soil temperature at the 4-inch soil depth reaches 65°F and preferably timed just prior to a rainfall (¼ to ½ inch) event. Fields planted with Kabina or Kabina and Rizolex (or Vibrance) treated seeds can be treated with an effective fungicide such as Quadris, Priaxor and Proline when the plants are at the 4 to 6-leaf stage. The fungicide needs to get into the soil and as close as possible to the roots so treatment should be done before the leaves cover too much of the soil.  Timing the fungicide application before a half-inch rainfall is ideal to get the fungicide to protect the roots and target the pathogen in the soil. Many growers with early planted sugarbeet have applied a fungicide and have had timely rains to move the products into the soil and surrounding roots which should result in adequate protection. Growers with replanted beets, especially in a field with a history of moderate to severe Rhizoctonia should also make a timely fungicide application to protect against Rhizoctonia root rot.  

ppth.khan.1

Mohamed Khan

Extension Sugarbeet Specialist

NDSU & U of MN

This site is supported in part by the Crop Protection and Pest Management Program [grant no. 2017-70006-27144/accession 1013592] from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed are those of the website author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

USDA logo

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.