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United States Department of Agriculture

Agricultural Research Service

Title: Relations of cercospora beticola with host plants and fungal antagonists

Authors
item Lartey, Robert
item Ghoshroy, Soumitra - NEW MEXICO STATE UNIV.
item Caesar, Thecan
item Lenssen, Andrew
item Evans, Robert

Submitted to: American Phytopathological Society Press
Publication Type: Book / Chapter
Publication Acceptance Date: August 28, 2008
Publication Date: February 26, 2010
Citation: Lartey, R.T., Ghoshroy, S., Caesar, T., Lenssen, A.W., Evans, R.G. 2010. Chapter 7: Relations of cercospora beticola with host plants and fungal antagonists. In: Lartey R.T., Weiland, J.J., Panella, L., Crous, P.W., and Windels, C.E., editors. Cercospora Leaf Spot of Sugar Beet and Related Species. St. Paul, MN: American Phytopathological Society Press. p. 77-90.

Interpretive Summary: Cercospora beticola Sacc., the causal agent of Cercospora leaf spot (CLS) of sugar beet, is the most serious disease problem of sugar beet. When not managed, CLS can result in significant root yield loss, reduced sugar content of beet roots, poor sugar extraction, and root storage life. Management of CLS of sugar beet has been a high priority for the sugar beet industry. We initiated research on interaction among host plants, fungal antagonists and C. beticola as a step towards an improved comprehensive management system against CLS. This system is based on: (1) Rapid detection, identification and subsequent elimination of alternate hosts, (2) Critical examination of interactions between the pathogen and host plants, and (3) Examination and understanding of the basis for antagonism by potential biological agents. Investigations focused on interaction of C. beticola with a newly confirmed host, safflower, and sugar beet in addition to the fungal antagonists, Trichoderma spp. and Laetisaria arvalis. The research provides the foundation for rapid detection and identification of alternate crop and weed hosts that could lead to selection of appropriate crops for rotation with sugar beet, as well as elimination of potential alternate hosts. A critical examination of biological interactions between C. beticola and various hosts, such as safflower and sugar beet, may provide clues on breeding for resistance. Finally, a novel approach to combat CLS would be to decrease or even eliminate primary inoculum with microbial antagonists.

Technical Abstract: Sugar beet, a probable native of the humid parts of western and southern Asia was developed in Europe from the beet root, (Runkelrübe). First US, sugar factory was established in Northampton, Massachusetts in 1837. Ensuing success of the US sugar industry should be credited to Goessmann, a chemist at the Massachusetts Agricultural College. The first successful sugar beet based sugar factory was built at Alvarado, California in 1870. Cercospora leaf spot (CLS) of sugar beet caused by Cercospora beticola Sacc., was first described by Saccardo in 1876. Ten years after description of the genus, the disease was noted as one of the most destructive diseases of sugar beet in Germany. Within three decades of establishment of the sugar beet industry in the US and two decades of description of the pathogen, CLS was established as a serious problem for the sugar beet industry. Today, the disease is still considered to be the most important foliar disease of sugar beets and has been reported wherever sugar beet is grown, causing significant root yield loss, reduced sugar content of beet roots, sugar extractable sugar and root storage life. Current management strategies of CLS include cultural practices, use of resistant varieties, predictive models for when to spray fungicides, scouting and application of fungicides. In this paper, we present results of ongoing work as steps toward developing an improved comprehensive management system against CLS. These are based on: (i) Rapid detection, identification and subsequent elimination of alternate hosts, (ii) Critical examination of interactions between the pathogen and host plants to understand the basis for resistance against C. beticola, and (iii) Examination and understanding of basis for antagonism by potential biological agents. The work forms the basis for rapid detection and identification of alternate crop and weed hosts that could lead to selection of appropriate crops for rotation with sugar beet, as well as elimination of potential alternate hosts. A critical examination of biological interactions between C. beticola and various hosts such as safflower and sugar beet may provide clues on breeding for resistance. Finally, a new approach to combat CLS could be direct control of C. beticola, decrease or even eliminate primary inoculum from target sources with fungal antagonists such as Trichoderma spp and Laetisaria arvalis.

Last Modified: 8/1/2014
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