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United States Department of Agriculture

Agricultural Research Service

Research Project: Nonchemical Pest Control and Enhanced Sugar Beet Germplasm Via Traditional and Molecular Technologies Title: Sugar Beet Resistance to Rhizoctonia Root and Crown Rot: Where does it fit in?

Author
item Panella, Leonard

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: January 5, 2013
Publication Date: January 10, 2013
Citation: Panella, L.W. 2013. Sugar Beet Resistance to Rhizoctonia Root and Crown Rot: Where does it fit in? Meeting Abstract. Jan. 9-10, 2013.

Technical Abstract: In sugar beet (Beta vulgaris L.), Rhizoctonia root- or crown-rot is caused by Rhizoctonia solani (AG-2-2). Seedling damping-off in sugar beet is caused by R. solani of both anastomosis groups, AG-2-2 and AG-4. Rhizoctonia solani subgroup AG-2-2 IV had been considered to be the primary cause of Rhizoctonia root and crown rot in most sugar beet growing regions of the USA, but AG-2-2 IIIB also commonly causes disease in sugar beet. Especially in the Red River Valley, but also across the US, recent increases in production of crops susceptible to AG-2-2 IIIB such as soybean and corn in conjunction, with a decrease in acreage of non-host crops of AG-2-2 IIIB, are associated with a growth in the prevalence of AG-2-2 IIIB in sugarbeet growing area. And strains of AG-2-2 IIIB cause more severe disease on sugarbeet. Twenty-five years ago, Leach and Garber reviewed resistance to Rhizoctonia infection and concluded, "In general, while it has been possible to identify differences among cultivars or selections in susceptibility to Rhizoctonia infection, it is extremely rare that a high degree of resistance has been found or produced by selection or breeding within a susceptible host species." However, one of the most effective and environmentally safe ways to manage plant disease is with resistant germplasm. Soilborne pathogens like Rhizoctonia are often difficult to control chemically. Fumigation is expensive, providing only a temporary solution. The use of QuadrisJ provides the first real chemical control for this disease. However, timing of application is crucial. Additionally, spot spraying can be time consuming, and spraying a whole field because of a few patches of disease also can be expensive. The use of resistant germplasm, coupled with crop rotation, other cultural practices, and judicious use of chemical protectants, can provide excellent management of diseases caused by Rhizoctonia solani.

Last Modified: 11/20/2014
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