IMPACT OF ROOT DISEASES ON STORAGE

Authors: Campbell, Larry; Fugate, Karen

Submitted to: Sugarbeet Research and Extension Reports
Publication Type: Proceedings
Publication Acceptance Date: 1/24/2003
Publication Date: 1/31/2003
Citation: CAMPBELL, L.G., KLOTZ, K.L. IMPACT OF ROOT DISEASES ON STORAGE. 2002 SUGARBEET RESEARCH AND EXTENSION REPORTS, cooperative extension service, North Dakota State University. 2003. v. 33 p. 254-257.

Interpretive Summary: In recent years, Aphanomyces root rot and rhizomania have become more prevalent throughout the sugarbeet production areas of Minnesota and eastern North Dakota. Accompanying any increase in root disease in the field will be an increase in the proportion of diseased roots placed in storage piles. Information on the effects of root disease on initial quality and storability would, therefore, 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 rate and extractable sucrose per ton were determined for roots exhibiting varying degrees of Aphanomyces or rhizomania symptoms. Respiration rates of roots with moderate or severe Aphanomyces were substantially higher than respiration rates of healthy roots. The higher respiration rates of Aphanomyces infected roots are not only indicative of higher sugar loss but would also increase storage pile temperatures and increase sugar loss in adjacent healthy roots. The impact of genetic resistance on storage properties appeared to be negligible as neither rhizomania nor Aphanomyces resistance was associated with higher respiration rates in the absence of disease.

Technical Abstract: In recent years, the sugarbeet (Beta vulgaris L.) root diseases, Aphanomyces and rhizomania (causal agents Aphanomyces cochlioides Drechal. and Beet Necrotic Yellow Vein Virus, respectively), have become more prevalent throughout Minnesota and eastern North Dakota. Accompanying any increase in root disease in the field will be an increase in the proportion of diseased roots placed in storage piles. Information on the effects of root disease on initial quality and storability would, therefore, 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 rate and extractable sucrose per ton were determined for roots exhibiting varying degrees of Aphanomyces or rhizomania symptoms. Respiration rates of roots with moderate or severe Aphanomyces were substantially higher than respiration rates of healthy roots. Initial observations of the effects of rhizomania on sugarbeet root storage properties suggest that rhizomania is not nearly as detrimental to root storability as Aphanomyces, however, this indication is based on limited data. The impact of genetic resistance on storage properties appeared to be negligible as neither rhizomania nor Aphanomyces resistance was associated with higher respiration rates in the absence of disease.