Submitted to: Plant Disease Management Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 25, 2013
Publication Date: March 11, 2013
Repository URL: http://handle.nal.usda.gov/10113/56007
Citation: Strausbaugh, C.A., Eujayl, I.A. 2013. Rhizoctonia root rot resistance in commercial sugar beet cultivars in Twin Falls County, ID, 2012. Plant Disease Management Reports. 7:FC075. Interpretive Summary: Rhizoctonia root rot caused by Rhizoctonia solani is of considerable concern in sugar beet production areas. Rhizoctonia root rot can reduce yield by 50% or more, but also seems to be on the increase and can be associated with losses in storage. The primary means of controlling this rot is host resistance. Thus, 26 commercial sugar beet cultivars were screened for resistance to this rot while using 3 different R. solani strains. Regardless of the strain used to screen the cultivars, the responses were similar. The most susceptible cultivars had most of the root surface area rotted. The three most resistant cultivars performed well against all strains and variables, but still had half the root surface area rotted. Additional efforts need to be made to get more resistance to this disease problem in commercial sugar beet cultivars.
Technical Abstract: Rhizoctonia root rot continues to be a concerning problem in sugar beet production areas. To investigate resistance to this disease in 26 commercial sugar beet cultivars, field studies were conducted with three Rhizoctonia solani AG-2-2 IIIB strains. Based on means for the 26 cultivars, surface rot ranged from 0 to 96% depending on the strain-cultivar combination. Both the number of dead plants and root surface area rotted resulted in significant (P < 0.0002) cultivar differences. Based on Spearman’s rank correlation coefficient, there was always a significant relationship (P < 0.0390) when comparing cultivar performance across all three strains regardless of disease variable. The three most resistant cultivars performed well against all strains and variables, but still had half the root surface area rotted. Additional efforts need to be made to get more resistance to this disease problem in commercial sugar beet cultivars.