Sorghum as a bioenergy crop in Alabama: Disease and yield evaluations
K. L. BOWEN (1), A. K. Hagan (1), A. C. Rocateli (2), R. L. Raper (3), E. B. Schwab (4), D. Bransby (2), F. J. Arriaga (5), K. S. Balkcom (5)
(1) Auburn University, Auburn, AL, U.S.A.; (2) Agronomy and Soils, Auburn University, AL, U.S.A.; (3) USDA-ARS Dale Bumpers Research Center, Booneville, AR, U.S.A.; (4) USDA-NRCS, Auburn, AL, U.S.A.; (5) USDA-ARS National Soil Dynamics Lab, Auburn, AL, U.S.A.
Phytopathology 100:S16

In Alabama, in 2009, several studies were monitored to evaluate the impact of various production practices on disease occurrence and the effect of diseases on yields of sorghum. Sweet sorghum cultivars, as well as grain and forage sorghum, were included in these studies. Fresh (biomass) and dry weights as well as juice and Brix (% sucrose) yields were recorded. In south-central Alabama (Brewton), the best cultivars, including ‘M81-E’ and ‘Dale’, yielded in excess of 80 tons per hectare fresh weight biomass in the absence of diseases. Zonate leaf spot (Gloeocercospora sorghi) was the dominant disease in south Alabama (Baldwin Co.); however, anthracnose (Colletotrichum graminicola) occurred primarily on the sweet sorghum M81-E. Anthracnose also predominated on sorghum in east-central AL (Macon Co.). In one Macon Co. trial, anthracnose was lower in conventionally tilled plots than those under conservation tillage. Brix was negatively related to anthracnose intensity on M81-E in south AL, while this dry matter yield was negatively related to anthracnose in east-central AL on forage sorghum. Increasing nitrogen rates had little if any impact on disease severity or any yield parameter in south AL. However, more severe anthracnose was found with higher nitrogen rates and with later planting dates in sweet sorghum in Macon Co.