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ARS Home » Midwest Area » East Lansing, Michigan » Sugarbeet and Bean Research » Research » Publications at this Location » Publication #352025
Research Project: Genetic Characterization for Sugar Beet Improvement

Location: Sugarbeet and Bean Research

Title: Virulence of Rhizoctonia solani AG2-2 isolates on sugar beet (Beta vulgaris) in response to low temperature

Author
item MINIER, DOUGLAS - Michigan State University
item Hanson, Linda

Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2017
Publication Date: 12/1/2017
Citation: Minier, D.H., Hanson, L.E. 2017. Virulence of Rhizoctonia solani AG2-2 isolates on sugar beet (Beta vulgaris) in response to low temperature. Phytopathology. 107:S5.174.

Interpretive Summary:

Technical Abstract: Rhizoctonia solani AG2-2 is not only the causal agent of Rhizoctonia root and crown rot in sugar beet (Beta vulgaris) but it can also cause a seedling damping-off. Significant losses can occur in all regions where sugar beets are grown. One recommendation for managing seedling losses to R. solani is to plant early when the soil is still cool and the risk of infection is reduced. However, there are varying reports regarding what temperature presents a reduced risk with the most widely cited temperature below which R. solani becomes inactive being 15°C (60°F). In the current study, we evaluate the virulence of 35 R. solani AG2-2 isolates on sugar beet at 11°C and determine how virulence relates to the phylogenetic groups identified by Martin et al. (2014). Twenty-seven isolates had disease severity scores significantly higher than the controls when tested at 11°C and 16% of the inoculated plants were rated as dead at the end of the experiment indicating that even at 11°C, considerable stand losses are possible. Isolates in phylogenetic Group 2A were, on average, more aggressive than isolates in Group 2B at 11°C. While early season planting does provide some protection against damping-off, our data indicates that growers should not consider early planting to provide ‘no risk’ of R. solani infection. The risk in any particular field will depend on the specific isolates present as well as soil temperature, moisture and amount of inoculum.