Location: Sugarbeet and Bean ResearchTitle: Rhizoctonia crown and root rot disease nursery
|CORDER, HOLLY - Michigan State University|
Submitted to: Annual Beet Sugar Development Foundation Research Report
Publication Type: Research Notes
Publication Acceptance Date: 3/31/2017
Publication Date: 4/1/2017
Citation: Hanson, L.E., McGrath, J.M., Corder, H., Goodwill, T.R. 2017. Rhizoctonia crown and root rot disease nursery. Annual Beet Sugar Development Foundation Research Report. Denver, Colorado: Beet Sugar Development Foundation. [CD-ROM].
Technical Abstract: The BSDF cooperative CRR Eastern Evaluation Nursery Rhizoctonia crown and root rot Evaluation Nursery in 2016 was a randomized complete-block design with five replications in 15 feet long, one-row plots (20 in row spacing), at the Saginaw Valley Research and Education Center near Frankenmuth, MI. Fertilizer was applied at 70lb N/A preplant. Seed was planted on May 8. Perpendicular alleyways were planted two weeks later. Weed control was using glyphosate at standard recommendations. The field was thinned by hand with the generous help of Michigan Sugar Cooperative. Inoculation with dry, ground, barley grain inoculum of Rhizoctonia solani isolate R-1 (AG-2-2) was applied to the crown of the plants on at a rate of 6 g per meter on June 28. A Gandy electrically driven applicator was used to apply the inoculum and the field was watered afterwards to ensure moisture for infection. Beets were harvested August 8-11 with a single row harvester. Each root was rated for rot on a scale of 0 (no damage) to 7 (dead plant with root completely rotted). A weighted average for disease severity per plot was determined (on a continuous scale between 0 and 7) to create a disease index (DI) for each entry. Analyses of variance (PROC ANOVA/GLM) were performed on disease indices. Variety disease index means for the entire nursery ranged from 4.8 to 6.8 (mean = 5.9), with the percent of roots classified as “harvestable” (less than 25% of the root rotted) ranging from 0% to 39% for the different varieties.