ARS | Publication request: Rhizoctonia and Bacterial Root Rot in Sugarbeet

Submitted to: The Sugarbeet
Publication Type: Trade Journal
Publication Acceptance Date: February 9, 2010
Publication Date: April 8, 2010
Repository URL: http://http:/eprints.nwisrl.ars.usda.gov/1360/1/1337.pdf
Citation: Strausbaugh, C.A., Eujayl, I.A. 2010. Rhizoctonia and Bacterial Root Rot in Sugarbeet. The Sugarbeet. Spring Issue:11-12.

Technical Abstract: Root rot in sugarbeet can cause losses approaching 50% or more in Idaho. To assess the distribution of root rot fungi and their relationship to bacterial root rot, commercial sugar beet roots were collected at harvest time in the Intermountain West (IMW). Isolations for both fungi and bacteria were conducted using standard microbiological techniques and the root area rotted was assessed. In the field survey, root rot averaged 6% for individual roots when fungi were isolated individually, while root rot averaged 71 and 68% when bacteria were isolated individually or in combination with other organisms, respectively. 47% of the Rhizoctonia solani isolates were AG-2-2 IIIB and 44% were AG-4. The majority of the AG-2-2 IIIB isolates were from the western portion of the production area in Idaho, while AG-4 isolates were more evenly distributed throughout the production area. Lactic acid bacteria (primarily Leuconostoc and Lactobacillus) were the most frequently isolated bacteria from roots with a wet-bacterial rot. Traditionally fungal root rots have been the main focus of breeding programs, but with the larger root area rotted by lactic acid bacteria, especially Leuconostoc, these bacteria should not be ignored in breeding efforts. The interaction between the R. solani and Leuconostoc may require screening cultivars for both fungal and bacterial resistance to alleviate root rot problems in the IMW.