Author
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Campbell, Larry |
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Fugate, Karen |
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Submitted to: Sugarbeet Research and Extension Reports
Publication Type: Experiment Station Publication Acceptance Date: 1/30/2002 Publication Date: N/A Citation: N/A Interpretive Summary: In recent years, sugarbeet root diseases have become more prevalent throughout Minnesota and eastern North Dakota. Rhizomania was positively identified in southern Minnesota in 1996 and has since been observed in the southern Red River Valley of North Dakota and Minnesota. Rhizomania resistant hybrids are available and provide the only practical control. Because of its persistence in the soil and the lack of effective control methods available, Aphanomyces is especially threatening. Any increase in root rots in the field will be accompanied by an increase in the proportion of roots with rot that are placed in storage piles. Information on the effects of root-rot severity on initial quality and storability would assist growers and agriculturalists when determining the disease severity that would justify not harvesting a field or if roots from diseased fields should be segregated and processed first. Respiration rates of roots with moderate or severe Aphanomyces were substantially higher than respiration rates of healthy roots. The higher respiration rates are not only indicative of high sugar loss but would increase storage pile temperatures and increase sugar losses of adjacent healthy roots. Neither Rhizomania nor Aphanomyces resistance appeared to be associated with higher respiration rates, in the absence of the diseases. Technical Abstract: In recent years, sugarbeet (Beta vulgaris L.) root diseases have become more prevalent throughout Minnesota and eastern North Dakota. Rhizomania (Beet Necrotic Yellow Vein Virus) was positively identified in southern Minnesota in 1996 and has since been observed in the southern Red River Valley of North Dakota and Minnesota. Rhizomania resistant hybrids are available and provide the only practical control. Because of its persistence in the soil and the lack of effective control methods available, Aphanomyces (caused by Aphanomyces cochlioides Drechsl.) is especially threatening. Any increase in root rots in the field will be accompanied by an increase in the proportion of roots with rot that are placed in storage piles. Information on the effects of root-rot severity on initial quality and storability would assist growers and agriculturalists when determining the disease severity that would justify not harvesting a field or if roots from diseased fields should be segregated and processed first. Roots with severe Aphanomyces had storage respirations rates four to five times higher than healthy roots and extractable sugar was reduced from 300 pounds per ton for healthy roots to 180 pounds per ton for roots with severe Aphanomyces. It appears that Rhizomania infected roots may have slightly higher respiration rates than healthy roots but the effect is considerably less than that associated with Aphanomyces. Neither Rhizomania nor Aphanomyces resistance appears to be associated with higher respiration rates, in the absence of the diseases. |
