A strategy for controlling Cercospora leaf spot, caused by Cercospora beticola, by combining induced host resistance and chemical pathogen control and its implications for sugar beet yield

Author(s):  
Saad Z. Morsy ◽  
Mohamed F. Shady ◽  
Moustafa I. Gouda ◽  
Bahnasy A. Kamereldawla ◽  
Mohamed A. S. Abdelrazek
2021 ◽  
Author(s):  
Rebecca Spanner ◽  
Jonathan Neubauer ◽  
Thies M. Heick ◽  
Michael Grusak ◽  
Olivia Hamilton ◽  
...  

Cercospora leaf spot (CLS) is a globally important disease of sugar beet (Beta vulgaris L.) caused by the fungus Cercospora beticola. Long-distance movement of C. beticola has been indirectly evidenced in recent population genetic studies, suggesting potential dispersal via seed. Commercial sugar beet “seed” consists of the reproductive fruit (true seed surrounded by maternal pericarp tissue) coated in artificial pellet material. In this study, we confirmed the presence of viable C. beticola in sugar beet fruit for 10 of 37 tested seed lots. All isolates harbored the G143A mutation associated with quinone outside inhibitor resistance and 32 of 38 isolates had reduced demethylation inhibitor sensitivity (EC50 > 1 µg/ml). Planting of commercial sugar beet seed demonstrated the ability of seed-borne inoculum to initiate CLS in sugar beet. Cercospora beticola DNA was detected in DNA isolated from xylem sap, suggesting the vascular system is used to systemically colonize the host. We established nuclear ribosomal internal transcribed spacer region amplicon sequencing using the MinION platform to detect fungi in sugar beet fruit. Fungi from 19 different genera were identified from 11 different sugar beet seed lots, but Fusarium, Alternaria, and Cercospora were consistently the three most dominant taxa, comprising an average of 93% relative read abundance over 11 seed lots. We also present evidence that C. beticola resides in the pericarp of sugar beet fruit, rather than the true seed. The presence of seed-borne inoculum should be considered when implementing integrated disease management strategies for CLS of sugar beet in the future.


Plant Disease ◽  
2010 ◽  
Vol 94 (11) ◽  
pp. 1272-1282 ◽  
Author(s):  
Gary A. Secor ◽  
Viviana V. Rivera ◽  
M. F. R. Khan ◽  
Neil C. Gudmestad

Cercospora leaf spot, caused by the fungus Cercospora beticola Sacc., is the most serious and important foliar disease of sugar beet (Beta vulgaris L.) wherever it is grown worldwide. Cercospora leaf spot first caused economic damage in North Dakota and Minnesota in 1980, and the disease is now endemic. This is the largest production area for sugar beet in the United States, producing 5.5 to 6.0 million metric tons on approximately 300,000 ha, which is 56% of the sugar beet production in the United States. This Plant Disease feature article details a cooperative effort among the participants in the sugar beet industry in this growing area and represents a successful collaboration and team effort to confront and change a fungicide resistance crisis to a fungicide success program. As a case study of success for managing fungicide resistance, it will serve as an example to other pathogen–fungicide systems and provide inspiration and ideas for long-term disease management by fungicides.


2009 ◽  
Vol 99 (7) ◽  
pp. 796-801 ◽  
Author(s):  
J. Khan ◽  
A. Qi ◽  
M. F. R. Khan

Cercospora leaf spot, caused by Cercospora beticola, is the most damaging foliar disease of sugar beet in Minnesota (MN) and North Dakota (ND). Research was conducted to characterize the temporal progression of aerial concentration of C. beticola conidia in association with the environment and disease severity in sugar beet. In 2003 and 2004, volumetric spore traps were placed within inoculated sugar beet plots to determine daily dispersal of conidia at Breckenridge, MN, and St. Thomas, ND. Plots were rated weekly for disease severity. At both locations, conidia were first collected in early July 2003 and late June in 2004. Peaks of conidia per cubic meter of air were observed with maxima in late August 2003 and in early September 2004 at both locations. Peaks of airborne conidium concentration were significantly correlated with the average temperature of daily hours when relative humidity was greater than 87%. Weekly mean hourly conidia per cubic meter of air was significantly (P < 0.01) associated with disease severity during both years and across locations. This study showed that C. beticola conidial numbers may be used to estimate potential disease severity that, with further research, could be incorporated in a disease forecasting model to rationalize Cercospora leaf spot management.


1968 ◽  
Vol 34 (1) ◽  
pp. 1-6
Author(s):  
Wataru IIDA ◽  
Kazuichi KUDO ◽  
Takashi KIMIGAFUKURO

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