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2010 APS Annual Meeting

 

Survey of diseases of agronomic switchgrass in Tennessee
A. L. VU (1), M. M. Dee (1), T. Russell (1), O. L. Fajolu (1), K. D. Gwinn (1), J. Zale (1), B. H. Ownley (1)
(1) University of Tennessee, Knoxville, TN, U.S.A.
Phytopathology 100:S131

Switchgrass (Panicum virgatum L.) is a perennial warm-season (C4) native grass currently being investigated for use in biomass-based ethanol production in Tennessee. However, little is known about diseases that occur, or the impact of these diseases on the success of this crop. Reducing disease could significantly increase biomass yield and overall crop quality, particularly in the southeastern U.S. where large monocultures are being planted. The goal of this project was to identify fungal pathogens of switchgrass to gain an understanding of the role of disease in the overall efficiency and sustainability of switchgrass as a biofuel crop. Naturally infected ‘Alamo’ and ‘Blackwell’ switchgrass plants were collected from growers’ fields in Vonore, TN in summer 2009 and agronomic research plots in Knoxville, TN in winter 2007 through spring 2008. Fungi were isolated from diseased plants and pathogenicity was confirmed with Koch’s postulates in growth chamber studies. Several fungal pathogens were isolated also from seed. Pathogenic species of Alternaria, Bipolaris, Curvularia, and Fusarium have been identified; several of which have not been described previously on switchgrass, but are known to reduce quality and yield of other crops. Species identification was based on morphology of conidia and conidiogenous cells, colony characteristics, colony growth at various temperatures, and confirmed with internal transcribed spacer (ITS) sequences of ribosomal DNA.

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