Spread growth and reproductive potential for brown flatsedge (Cyperus fuscus)

Authors: Bryson, Charles; CARTER, RICHARD - Valdosta State University

Submitted to: Invasive Plant Science and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2010
Publication Date: 7/1/2010
Citation: Bryson, C.T., Carter, R. 2010. Spread growth and reproductive potential for brown flatsedge (Cyperus fuscus). Journal of Invasive Plant Science and Management. 3:240-245.

Interpretive Summary: Brown flatsedge is an annual non-native, invasive weed that continues to move south and westward in the U.S.A. It was apparently introduced from contaminated ballast in the Boston, MA, area during the late1800s. Brown flatsedge is reported new to Arkansas and Mississippi and biological and ecological growth parameters are presented from field observations and controlled greenhouse experiments. In optimum environmental conditions, brown flatsedge grows rapidly and populations are capable of producing multiple generations per year and from 69 million to 2.2 billion seeds per ha annually. Brown flatsedge plants produced seed by nine weeks after emergence and fruiting occurred by 5 weeks after emergence. Currently, brown flatsedge seems to be in the lag phase and is poised to infest native plant communities and rice production areas in the southeastern U.S.A. Additional research is needed to develop effective containment and control strategies to prevent brown flatsedge from becoming a major weed problem.

Technical Abstract: Brown flatsedge (Cyperus fuscus L.) is native to Europe, Asia, Indian subcontinent, and Mediterranean Region of Northern Africa. It was apparently introduced into North America in the late 1800s and has steadily moved southward and westward. Brown flatsedge is reported new to Arkansas and Mississippi herewith. Field observations from early spring until frost were made between 2003 and 2007 at populations present at three sites: Chicot County, Arkansas, and Pearl River and Washington counties, Mississippi. Under natural field conditions, brown flatsedge plants germinated from late March and early April until frost. The first inflorescences were observed in mid May and seed production continued until frost. In field populations the average number of scales per spikelet, inflorescences per plant, and spikelets per inflorescence were 15, 28, and 33, respectively. Greenhouse experiments were established in 2007 at Stoneville, MS, to determine growth parameters and the reproductive potential of brown flatsedge. In greenhouse experiments by 10 WAE, brown flatsedge plants were30.2 cm tall and 63.9 cm in diameter and dry weights were 1.4, 2.0, 1.0, 0.5, and 1.9 g for roots, leaves, culms, bracts, and inflorescences, respectively. Brown flatsedge culms and inflorescences appeared 5 WAE and by 9 WAE all plants were producing seed. Brown flatsedge may be in the lag phase and could pose a threat to natural plant communities and rice agriculture in Arkansas, Louisiana, Mississippi, Missouri, Tennessee, and Texas. Additional research is needed to develop inexpensive and effective control methods should brown flatsedge become a weed problem.