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Poster: Biology & Disease Mgmt: Integrated Pest Mgmt


Production practices impact yield parameters and disease severity on sweet and forage sorghum grown as biomass feedstock
A. HAGAN (1), S. Scott (1), K. Bowen (1) (1) Auburn University, U.S.A.

Sweet and forage sorghum are potential feedstocks for energy and chemical industries but the impact of production practices on diseases is largely unknown. Planting date (PD), nitrogen (N) rate, and variety impact were assessed in 2011 and 2012 on plant populations, above ground dry matter (ADM) yield, total fermentable sugar concentration (°Bx), and anthracnose severity. A factorial with year as the main plot, PD as the split-plot, N rate as the split split-plot, and sweet and forage sorghum variety as the split split split-plot was used. Disease assessment and harvest was at soft dough. Plant population was not impacted by any variable. ADM yield segregated by year, PD, and variety. Generally, similar ADM yield was noted at all N rates. M81-E sweet sorghum ADM yield trended higher than forage sorghum. °Bx varied by year, PD, and variety with values declining at the later PD. M81-E had a higher °Bx than either forage sorghum with 1990 having a higher °Bx in 2011 than SS405 in 2012. Anthracnose differed by year, PD, N rate and variety where disease severity was highest in 2012, when sorghum followed sorghum, and summer weather was wetter than 2011. In both years, M81-E had less anthracnose damage than either forage sorghum with SS405 having a higher disease rating in 2012 than 1990 in 2011 due to rotation and drier summer in latter year. Higher °Bx and anthracnose ratings were seen at 88 than 22 kg N ha-1. Anthracnose ratings were lower at the April than June PD.