|Carter, Richard -|
Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 24, 2011
Publication Date: February 24, 2012
Citation: Bryson, C.T., Carter, R. 2012. Growth, reproductive potential, and control strategies for deeproot sedge (Cyperus entreianus). Weed Technology. 26(1):122-129. Interpretive Summary: Deeproot sedge was probably introduced into the United States prior to 1940, but it was not recognized until 1990. Since 1990, deeproot sedge has spread at an alarming rate and is now known from 70 counties in Alabama, Florida, Georgia, Louisiana, Mississippi, and Texas. Research determined that this sedge is capable of moving much further northward and eastward in the United States. Moderate deeproot sedge populations can produce over 4 million seed per ha and the seed can persist in the soil for several years. All established deeproot sedge plants overwintered at Stoneville, MS. Mowing alone did not kill this sedge; however, weekly mowing prevented seed production. Several herbicides provide adequate control of deeproot sedge. Single herbicide applications of glyphosate, glufosonate, hexazinone, and MSMA provided better than 85% control and more than a 7-fold reduction of plant biomass. Additional research is needed to continue to develop preventative and control strategies for deeproot sedge.
Technical Abstract: Greenhouse, growth chamber, and field studies were conducted at Stoneville, MS in 2000-2008 to determine the growth rate, reproductive and overwintering potential, and control of deeproot sedge. In growth chamber studies, deeproot sedge growth rate (height) and plant dry weights were greatest for 25/35 C (night/day) when compared to regimes of 5/15, 15/25, and 20/30 C. Based on the average number of scales (fruiting sites/spikelet), spikelets/inflorescence, and culms/plant, deeproot sedge reproductive potential was 2.6-, 6.2-, and 17.4-fold greater than Surinam sedge, green sedge, and knob sedge, respectively. A single plant of deeprooted sedge produced an average of 85,500 achenes annually. Mowing at 15-cm height weekly prevented achene production, but did not kill deeproot sedge plants. The average number of inflorescences produced was 1.2 to 4 times greater in two and one yr old deeproot sedge plants, respectively, when compared to unmowed plants. Mature deeproot sedge achenes were produced between monthly mowings. In a 3-yr field study, glyphosate, glufosinate, hexazinone, and MSMA provided greater than 85% control of deeproot sedge and above the soil live deeproot sedge plant dry weights were reduced by 50, 64, 68, 72, 86, and 93% by dicamba, halsulfuron-methyl, MSMA, hexazinone, glufosinate, and glyphosate, respectively. All (100%) deeproot sedge plants one yr old or older overwintered at Stoneville, MS, 33oN latitude.