Doctor of Philosophy (PhD)


Plant, Environmental Management and Soil Sciences

Document Type



E. polystachya introduced at stand densities (SD) of 10,000 through 70,000 stolon segments/ha produced 5.4 to 6 stolons/introduced segment; however, 130,000 through 520,000 SD produced 1.4 to 2.1 stolons per introduced segment indicating increased intra- and inter-specific competition. Stolon production was greater than 160,000 plants/ha with 30,000 through 520,000 SD. The 520,000 SD produced a total stolon length of 318 km/ha and no difference was observed for the 260,000 SD. Total node production was 290,000 nodes/ha with an average of 29 nodes/introduced segment in the 10,000 SD and 5.4 to 9.8 nodes/introduced segment with 70,000 or greater SD indicating greater inter- and intra-specific competition. Total biomass indicated similar trends with increasing densities. In a depth of emergence study, E. polystachya shoot emergence was 31, 63, and 44% for stolons planted at the 0, 1.3, and 2.5 cm depth, respectively. Shoot emergence was 25% for 5 cm depth, which was similar to the 0 and 2.5 cm depth. In a greenhouse study, glyphosate controlled E. polystachya 91% and control was 65 to 78% for all herbicides evaluated. When treated with glyphosate, biomass production was 19% of the nontreated E. polystachya. Two studies evaluated herbicides labeled for Echinochloa crus-galli (L.) Beauv. control in rice for activity on E. polystachya. The first study included: 448 g/ha clomazone PRE, 448 g/ha clomazone plus 420 g ai/ha quinclorac delayed PRE, 448 g ai/ha pendimethalin plus 420 g/ha quinclorac DPRE, 70 g/ha imazethapyr at EPOST, and 175 g ai/ha mesotrione PRE. Each PRE herbicide was followed by 315 g/ha cyhalofop POST. The second study included: 208 g ai/ha cyhalofop EPOST fb 315 g/ha cyhalofop LPOST, 22 g ai/ha bispyribac EPOST fb 22 g/ha bispyribac LPOST, 66 g ai/ha fenoxaprop EPOST fb 86 g/ha fenoxaprop LPOST, 70 g ai/ha imazethapyr EPOST fb 70 g/ha imazethapyr LPOST and 50 g ai/ha penoxsulam MPOST. Each POST program was assessed with and without 448 g ai/ha clomazone PRE. In the first study, clomazone, imazethapyr, and pendimethalin plus quinclorac controlled E. polystachya 78 to 80%. In the second study, treatments including cyhalofop, imazethapyr, and penoxsulam controlled E. polystachya 76 to 84%.



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Committee Chair

Eric Webster