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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Soil Management and Sugarbeet Research » Research » Publications at this Location » Publication #301393
Title: Preparation on Inoculum of Rhizoctonia solani Kuhn for an Artificially Inoculated Field Trial

Author
item Vagher, Travis
item FENWICK, A - Beet Sugar Development Foundation
item Panella, Leonard

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/11/2014
Publication Date: 7/3/2014
Citation: Vagher, T.O., Fenwick, A.L., Panella, L.W. 2014. Preparation on Inoculum of Rhizoctonia solani Kuhn for an Artificially Inoculated Field Trial. Meeting Abstract. 74th IIRB Congress, Dresden, Germany, July 1-3, 2014.

Interpretive Summary:

Technical Abstract: Rhizoctonia crown root and rot, caused by Rhizoctonia solani Kühn, is a serious disease resulting in substantial economic losses in sugar beet production worldwide. A consistent, uniform disease pressure of the correct intensity is necessary to effectively screen sugar beet for resistance to Rhizoctonia crown root and rot in an artificially inoculated field trial. This study examined the substrate used to grow the R. solani inoculum, the method of substrate inoculation, and the pathogenicity of the different particle sizes within the inoculum. It was found that particles greater than 1.0 mm were the most consistently colonized and provided constant flow through the Gandy™ applicator, which is used to inoculate the field plots. The smaller particle sizes did not contain adequate amounts of the pathogen, contained substantial amounts of contaminating bacteria or fungi, and contributed to a varied rate of flow during distribution. We found hull-less barley the best performing substrate to inoculate with Rhizoctonia solani, and a liquid suspension of the pathogen in potato dextrose broth provided uniform colonization of the autoclaved barley during the incubation period. Mushroom spawn bags provided the ideal environment to reduce contamination and insure rapid colonization of the barley grain. The techniques described have increased the efficiency of inoculum production, decreased losses due to contamination, and guarantee a homogeneous inoculum in size and disease potential, which results in a uniform, consistent field infection.