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ARS Home » Midwest Area » East Lansing, Michigan » Sugarbeet and Bean Research » Research » Publications at this Location » Publication #431825
Research Project: Sugar Beet Genetics and Pathogen Interactions

Location: Sugarbeet and Bean Research

Title: Disease nurseries from USDA-ARS/BSDF/MSU collaborative research, 2025

Author
item Hanson, Linda
item CORDER, HOLLY - Michigan State University
item Goodwill, Thomas

Submitted to: Review / Technical Review
Publication Type: Research Technical Update
Publication Acceptance Date: 2/5/2026
Publication Date: 3/9/2026
Citation: Hanson, L.E., Corder, H.J., Goodwill, T.R. 2026. Disease nurseries from USDA-ARS/BSDF/MSU collaborative research, 2025. Review / Technical Review. in Research Results 2025. Michigan Sugarbeet REACh. Bay City, MI. pg 13-14.

Interpretive Summary:

Technical Abstract: The annual cooperative disease nurseries were conducted in 2025 at the Saginaw Valley Research and Education Center near Frankenmuth, MI. The nurseries included were conducted to screen sugarbeet germplasm, breeding lines, and commercial varieties for Rhizoctonia root and crown rot or Cercospora leaf spot susceptibility, the most important root and foliar disease of beet in the US, respectively. Both nurseries were in a randomized complete-block design with 15-foot-long plots with 20-inch row spacing. The Rhizoctonia root and crown rot plots were single-row plots with five replications while the Cercospora leaf spot plots were two-row plots with four replications. The Cercospora nursery was planted April 30 and the Rhizoctonia root and crown rot nursery was planted May 12. Fields were managed using recommended practices for the region, except that seed was overplanted and thinned by hand with the generous assistance of Michigan Sugar Cooperative. The Cercospora leaf spot nursery was spray inoculated with a spore suspension July 1. The susceptible control averaged disease severity of 5.9 on August 20 using a 0 to 10 scale where 0 is no disease and 10 is complete defoliation. Commercial varieties in the nursery ranged from a low of 4.3 to a high of 6.8. As in 2024, the CR+ materials showed evidence for resistance-breaking. The Rhizoctonia nursery was inoculated with Rhizoctonia solani AG 2-2 on July 10. Roots were harvested and rated for root rot severity on August 5 to 8. The lowest disease average disease index in the inoculated nursery was 3.5 with 53.2% “harvestable” (rating of 3 or less) and the highest was 5.5 with 7.1% harvestable using a rating scale of 0 to 7 where 0 is no root rot and 7 is root completely rotted and percent harvestable ranging from 0 to 100%. The lowest average rating was for the resistant control. The susceptible control averaged 5.4 with 7.7% harvestable. A non-inoculated check was included as part of a test for comparison to inoculated plants for an experiment using drones to determine if disease severity could be estimated from foliar reading with visible wavelength light, near infrared, or other wavelengths. The susceptible and resistant checks averaged 1.1 (88.6% harvestable) and 0.9 (91.0% harvestable) respectively, indicating a low natural inoculum level in the field.