|CUTTS, G.S. - University Of Georgia
|GREY, TIMOTHY - University Of Georgia
|VENCILL, WILLIAM - University Of Georgia
|LEE, R - University Of Georgia
|TUBBS, R - University Of Georgia
|Anderson, William - Bill
Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2010
Publication Date: 3/5/2011
Citation: Cutts, G., Webster, T.M., Grey, T.L., Vencill, W.K., Lee, R.D., Tubbs, R.S., Anderson, W.F. 2011. Herbicide effect on napiergrass (Pennisetum purpureum) control. Weed Science. 59:255-262.
Interpretive Summary: With increasing demands for energy, a need for alternate sources of energy is rising. There is an emphasis placed on evaluating cellulosic biofuel production as a practical alternative to crude oil-based liquid transportation fuels. Napiergrass has high biomass yields and has garnered potential as a possible feedstock for cellulosic biofuel production. A C4 perennial grass species found in tropical and subtropical areas throughout the world, napiergrass has been widely renowned to have the highest biomass productivity among herbaceous plants. Weed control during napiergrass establishment is a concern due to its slow early-season growth. Since commercial production has been limited, there are no herbicides registered for napiergrass production in Georgia. Napiergrass treated with pendimethalin plus atrazine had consistently greater dry biomass yields. Greater weed control was also observed, resulting in napiergrass with greater stem heights. Further analysis on other agronomic and economic establishment factors could determine the best herbicide option. Topical herbicide applications for weed control were also necessary during this study. Observations made with subsequent postemergence applications made in this study show strong potential for excellent weed control and crop tolerance to napiergrass. Further research is needed to explore these and other postemergence weed control options.
Technical Abstract: Napiergrass is a rapidly growing species under consideration for cellulosic biofuel production. However, information about agronomic production of napiergrass as a crop is lacking. Field screening studies were initiated to evaluate pre-emergence herbicides for weed control and napiergrass tolerance after autumn 2008 planting at Plains, GA and Fort Valley, GA. Treatments were applied prior to napiergrass emergence in March 2009 at both locations, and data collection included napiergrass stand counts, plant height, and biomass yield. At 12 weeks after application (WAA), stand counts were 1.0 plant per sq m at Fort Valley and 0.4 plant per sq m at Plains across all treatments. By 15 WAA, napiergrass had recovered from any herbicide injury, with no height differences. Napiergrass treated with pendimethalin plus atrazine yielded 55 and 86 Mg/ha at Plains and Fort Valley, respectively, compared to the nontreated control yield of 53 Mg/ha for both locations. Early season residual weed control is vital to napiergrass establishment and maximizing biomass yields.