ORCID Profile
0000-0002-7657-1251
Current Organisation
Texas A&M University Kingsville
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Publisher: Cambridge University Press (CUP)
Date: 06-2012
Abstract: Experiments were conducted in the laboratory and screenhouse to determine the effects of scarification alternating day/night temperatures light, salt, and water stress seed burial depth and rice residue on seed germination and seedling emergence of threelobe morningglory, and to evaluate the response of this weed to commonly available POST herbicides in the Philippines. Germination was stimulated by seed scarification, suggesting that inhibition of germination in this species is mainly due to the hard seed coat. Germination of the scarified seeds was not influenced by the tested temperatures (alternating day/night temperatures of 25/15, 30/20, and 35/25 C) and light. The concentrations of sodium chloride, ranging from 0 to 250 mM, did not influence germination of the scarified seeds of threelobe morningglory. The osmotic potential required for 50% inhibition of maximum germination was −0.35 MPa, although some seeds germinated at −0.6 MPa. Seedling emergence was greatest for the seeds placed on the soil surface (96%), and emergence declined with increased burial depth in soil. The burial depth required for 50% inhibition of maximum emergence was 2.8 cm. No seedlings emerged from a burial depth of 6 cm or greater. Residues of up to 6 Mg ha −1 on the soil surface did not influence seedling emergence of threelobe morningglory. The herbicide 2,4-D at 400 g ai ha −1 provided excellent control of threelobe morningglory when applied at the four-leaf (100%) and six-leaf (97%) stages. However, at the eight-leaf stage, percent control was reduced to 67% and herbicide rate had to be increased twofold to achieve 95% control. The information gained from this study could contribute to developing components of integrated weed management strategies for threelobe morningglory. Soil inversion by tillage to bury weed seeds below their maximum depth of emergence and early application of an effective POST herbicide could serve as important tools for managing threelobe morningglory.
Publisher: Cambridge University Press (CUP)
Date: 09-2012
Abstract: The growth of spiny amaranth and longfruited primrose-willow was studied by growing them alone and in competition with 4 and 12 rice (cv. RC222) plants. Interference with 12 rice plants reduced the height of spiny amaranth beyond 6 wk after planting. The height of longfruited primrose-willow was significantly reduced by the crop interference starting from 4 wk after planting. Both weed species showed the ability to reduce the effects of rice interference by increasing leaf area, leaf and stem biomass in the upper half of the plant, and specific stem length. At 9 wk after planting, for ex le, longfruited primrose-willow had 89 and 99% leaf biomass in the upper half of the plant when grown with 4 and 12 rice plants compared with only 34% when grown alone. These values for spiny amaranth were 15, 29, and 72% when grown alone, with 4 rice plants, and 12 rice plants, respectively. Despite such plasticity, spiny amaranth's aboveground biomass at final harvest was reduced by 34 and 70% when grown with 4 and 12 rice plants, respectively, compared with its biomass without crop interference. The corresponding values for longfruited primrose-willow were 92 and 98%, respectively. These results suggest that uniform and high crop density could be an important tool to reduce competition from these weeds in direct-seeded rice.
Publisher: Elsevier BV
Date: 02-2015
Publisher: Hindawi Limited
Date: 2012
DOI: 10.1100/2012/123071
Abstract: The efficacy of bispyribac-sodium, fenoxaprop + ethoxysulfuron, and penoxsulam + cyhalofop was evaluated against barnyardgrass, Chinese sprangletop, junglerice, and southern crabgrass when applied at four-, six-, and eight-leaf stages. When applied at the four-leaf stage, bispyribac-sodium provided greater than 97% control of barnyardgrass, junglerice, and southern crabgrass however, it was slightly weak (74% control) on Chinese sprangletop. Irrespective of the weed species, fenoxaprop + ethoxysulfuron provided greater than 97% control when applied at the four-leaf stage. At the same leaf stage, penoxsulam + cyhalofop controlled 89 to 100% barnyardgrass, Chinese sprangletop, and junglerice and only 54% of southern crabgrass. The efficacy of herbicides was reduced when applied at the eight-leaf stage of the weeds however, at this stage, fenoxaprop + ethoxysulfuron was effective in controlling 99% of Chinese sprangletop. The results demonstrate the importance of early herbicide application in controlling the weeds. The study identified that at the six-leaf stage of the weeds, fenoxaprop + ethoxysulfuron can effectively control Chinese sprangletop and southern crabgrass, penoxsulam + cyhalofop can effectively control Chinese sprangletop, and bispyribac-sodium can effectively control junglerice.
Publisher: Cambridge University Press (CUP)
Date: 06-2013
Abstract: In Asia, a significant area under rice is affected by salinity. Salt stress can affect growth of crops as well as weeds. A study was conducted in a greenhouse to determine the effect of salinity (electrical conductivity [EC] of 1, 6, 12, 18, and 24 dS m −1 ) on growth of barnyardgrass, horse purslane, junglerice, and rice. Growth variables were analyzed using regression analysis. The tested levels of EC influenced leaf production of barnyardgrass and junglerice but not that of horse purslane. As compared with the control treatment (EC of 1 dS m −1 ), shoot biomass of barnyardgrass decreased by only 24% at 12 dS m −1 , whereas rice biomass declined by 59% at this level of EC. At EC of 24 dS m −1 , barnyardgrass still produced 4% of the biomass of the control treatment, whereas rice did not survive at this level of EC. Junglerice shoot biomass decreased by 73% at 18 dS m −1 EC compared with the control treatment, whereas rice shoot biomass declined by more than 86% at 18 dS m −1 EC. An EC of 10 dS m −1 was required to inhibit 50% shoot biomass of rice, whereas the EC to inhibit 50% shoot biomass of barnyardgrass and junglerice was 15 and 13 dS m −1 , respectively. Shoot biomass of horse purslane was not influenced by the tested levels of EC. At the highest EC (24 dS m −1 ), at which rice did not survive, horse purslane shoot biomass was similar to that of the control treatment. In all weed species, data for root biomass showed trends similar to those of shoot biomass. The results of this study suggest that weeds were more tolerant to salt than rice, and horse purslane was the most tolerant species among the weeds.
Publisher: Informa UK Limited
Date: 04-07-2013
Publisher: Cambridge University Press (CUP)
Date: 03-2013
Abstract: Weeds are the main constraint in the adoption of zero-till, dry-seeded rice systems because weeds and rice emerge simultaneously in these systems, and there is no standing water at crop establishment to suppress weeds. A study was conducted during the wet season of 2011 and the dry season of 2012 at the International Rice Research Institute to evaluate the performance of different herbicides in mechanized-sown, zero-till dry-seeded rice. Among the treatments evaluated, oxadiazon followed by penoxsulam + cyhalofop followed by one hand-weeding at 42 d after sowing, provided 23 to 35% higher yield than the nontreated control. The yields in the oxadiazon-treated plots were similar to those in the weed-free plots. Some weed species, including eclipta and doveweed, were not controlled by the evaluated herbicides. Therefore, there is a need to evaluate additional herbicides and to integrate them with cultural weed management strategies to manage such problematic weeds.
Publisher: Cambridge University Press (CUP)
Date: 12-2012
Abstract: Studies were conducted in a screenhouse to determine the interaction of rice residue as mulch (0, 3, and 6 t ha −1 ) and herbicides (nontreated, oxadiazon at 0.5 and 1.0 kg ai ha −1 , and pendimethalin at 1.0 and 2.0 kg ai ha −1 ) on seedling emergence and biomass of barnyardgrass, crowfootgrass, junglerice, and rice flatsedge. Regardless of the residue amount, crowfootgrass and junglerice were effectively controlled by all herbicide treatments. No seedlings of these weed species escaped the herbicides when applied in the presence of residue cover. There was no survival of barnyardgrass seedlings when both herbicides were applied on bare soil (without residue cover) however, some seedlings survived oxadiazon and pendimethalin when applied in the presence of residue cover. For rice flatsedge, the herbicide applications in the presence of residue cover resulted in lower weed control than in the absence of residue. These results suggest that some weed species can escape the application of PRE herbicides in conservation agriculture systems in which residue can bind soil-applied herbicides and result in lower efficacy.
Publisher: Elsevier BV
Date: 12-2013
Publisher: Cambridge University Press (CUP)
Date: 09-2013
Abstract: Crop residues acting as mulches can influence weed seedling emergence and weed biomass. A field study was conducted to evaluate the effect of rice residue amounts (0, 3, and 6 t ha −1 ) on seedling emergence of eight weed species in zero-till dry-seeded rice. The highest seedling emergence of spiny amaranth, southern crabgrass, crowfootgrass, junglerice, eclipta, goosegrass, and Chinese sprangletop was observed in the absence of residue. Seedling emergence of these weeds declined with increasing residue amounts however, the greatest and most substantial reductions in emergence occurred with 6 t ha −1 of residue. The presence of residue also resulted in less weed biomass than with the no-residue treatment. The emergence and biomass of threelobe morningglory seedlings, however, were not influenced by residue amounts. The use of residue also increased the time taken to reach 50% of maximum emergence for some species, for ex le, spiny amaranth and Chinese sprangletop. The results of our study suggest that the use of residue at high rates can help suppress seedling emergence and growth of many weeds. However, there is a need to integrate other weed management strategies with residue retention to achieve season-long weed control.
No related grants have been discovered for Seth Bernard Abugho.