THE SIGNIFICANCE OF CYPERACEAE AS WEEDS

Authors: Bryson, Charles; CARTER, RICHARD - VALDOSTA ST UNIV

Submitted to: Systematic Botany
Publication Type: Book / Chapter
Publication Acceptance Date: 1/18/2005
Publication Date: 12/22/2008
Citation: Bryson, C.T. and Carter, R. 2008. IN: Sedges: Uses, Diversity, and Systematics of the Cyperaceae. Eds., Charles T. Bryson and Richard Carter. The significance of cyperaceae as weeds. Systematic Botany, pp. 15-101.

Interpretive Summary: Purple nutsedge is considered to be the world's worst agricultural weed, while four other sedges are considered among the 40 worst agricultural weeds worldwide. About 10 percent of the species in the sedge family are considered weeds of agriculture, forests, natural, or urban areas. Many of the worst sedge weeds have been introduced from other regions, have become extremely invasive, and cause great economic losses in the most fertile and productive farmland worldwide. This publication is the most comprehensive overview of weedy sedges ever assembled. It provides information never before published on several sedge species that currently have restricted distributions, but possess all the traits of the most pernicious weedy sedges. Lists of weedy sedges and sedges known or suspected to be spread by human activity is also the most comprehensive ever assembled in a single publication.

Technical Abstract: Weedy Cyperaceae adversely affect natural plant communities and the health of humans and livestock and are major deterrents to agricultural and forest productivity. Most weeds are exogenous and have traits that give them biological and reproductive advantages over other plants. Of an estimated 8,000 species of weeds worldwide, only about 200 species cause approximately 95% of the problems in production of food, feed, fiber, and livestock. Weeds cost $ billions in agriculture, forestry, and urban areas and threaten diversity in natural communities worldwide. About 25% of the world's weeds are monocots. Of these, sedges are among the most troublesome and difficult to control. The most important cyperaceous weeds in terms of their adverse effect on agriculture include Cyperus rotundus L., C. esculentus L., C. difformis L., C. iria L., and the Fimbristylis miliacea (L.) Vahl/F. dichotoma (L.) Vahl complex, ranking first, sixteenth, thirty second, thirty third, and fortieth among the world's worst weeds, respectively. An overview is provided on cyperaceous weeds, including economic losses, population dynamics, control methods, identification, biology, ecology, dispersal mechanisms, spread, and discussions of major weeds of agriculture, forestry, urban areas, and natural communities.