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Ecology, Physiology, and Management of Cogongrass (Imperata cylindrica)


Cogongrass (Imperata cylindrica (L.) Beauv.) is a problem weed throughout tropical and subtropical regions of the world, and in the southeastern United States has invaded forests, rangeland, reclaimed mined areas, roadsides, and natural ecosystems. Invasive weeds such as cogongrass impede the restoration of mined land. Fundamental applied research was performed to develop environmentally and economically sound strategies to control cogongrass. Laboratory, greenhouse, and field research was conducted to study cogongrass reproduction, population genetics, apical dominance in rhizomes, and integrated management of cogongrass. Cogongrass, an obligate out crosser, is a prolific producer of wind blown seed with high genetic diversity. The apical buds and rhizomes of cogongrass are mostly dormant, some success was achieved in breaking bud dormancy. Autumn applications of glyphosate and imazapyr provided greater control than spring or summer applications. Discing alone provided only short-term control but 2 discings and split applications of imazapyr controlled cogongrass regrowth up to 96%, 12 months after treatment. Combinations of discing, herbicides, and revegetation with desirable plant species also provided control in some areas. Additional research is needed to determine the practices necessary to optimize the selection and establishment of desirable plant species for revegetation.