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Management of leaf blight and stalk rot diseases in biomass sorghum (Sorghum bicolor) grown in the U.S. Mid-Atlantic

Christian Aguilar: Virginia Tech Tidewater Agricultural Research and Extension Center

<div>Biomass sorghum is currently being evaluated as an alternative crop and a potential feedstock for cellulosic ethanol production in the mid-Atlantic region. However, as a new crop, research pertaining to optimum agronomic practices is needed. Due to frequent rain events and high relative humidity, disease pressure by the sorghum anthracnose pathogen, <em>Colletotrichum</em> <em>sublineola</em>, is high. Therefore, sixteen high-biomass sorghum hybrids were evaluated at three field sites in Virginia under full-season and double-crop systems. Hybrids were visually screened for anthracnose leaf blight and stalk rot as well as lodging. Hybrid RX6 was the least susceptible to disease and lodging, while lines NS205 and NS204 were the most susceptible. Anthracnose susceptible hybrid NS212 was selected for evaluation of the efficacy of three fungicide formulations [fluxapyroxad + pyraclostrobin (Priaxor); azoxystrobin + propiconazole (QuiltXcel); and propiconazole (Tilt) combined with Priaxor]. Fungicides were applied at three timings, and anthracnose severity in treated plots was compared to a no fungicide control. A significant reduction in anthracnose was observed following a single application of Priaxor early in the growing season (<em>P</em> < 0.0001). However, due to chemical costs, fungicide control may not be an economical option for growers, and selection of disease resistant sorghum hybrids for biomass production is currently the best option for anthracnose management.</div>