Toxicity, Absorption, and Translocation of Soil-Applied Chlorimuron in Yellow and Purple Nutsedge (Cyperus esculentusandC. rotundus)

Weed Science ◽  
1989 ◽  
Vol 37 (2) ◽  
pp. 147-151 ◽  
Author(s):  
Krishna N. Reddy ◽  
Leo E. Bendixen

The activity of soil-applied chlorimuron in yellow and purple nutsedge was studied in greenhouse and laboratory experiments. Soil-applied chlorimuron decreased tuber sprouting by 80% in yellow nutsedge and by 30% in purple nutsedge at 60 g ai/ha. Chlorimuron decreased shoot emergence by 53 to 83% and shoot growth by 85 to 99% in both species at rates as low as 10 g/ha. Previous exposure of tubers to chlorimuron-treated soil reduced tuber resprouting by 20 to 25% in herbicide-free soil at 60 g/ha in both species. There was no rate response in shoot emergence from tubers previously exposed to chlorimuron, but shoot dry weight decreased by 60 to 81% in both species at 60 g/ha. At 12 h after application, 47% of the total14C applied to the shoot in yellow nutsedge and 32% of that applied in purple nutsedge were absorbed. However, less than 1% of the total14C applied was translocated out of the shoot and into the roots and tuber in either species. In both species, 1.3% of the14C applied to the roots and tuber was absorbed and 0.1% was translocated out of the roots and tuber into the shoot at 12 h after application. The pattern of root- and tuber-absorbed14C distribution indicated that the14C absorbed by the tuber remained in the tuber and that absorbed by the roots was translocated to the shoots.

1995 ◽  
Vol 9 (2) ◽  
pp. 277-280 ◽  
Author(s):  
J. K. Peterson ◽  
H. F. Harrison

The allelopathic influence of sweet potato cultivar ‘Regal’ on purple nutsedge was compared to the influence on yellow nutsedge under controlled conditions. Purple nutsedge shoot dry weight, total shoot length and tuber numbers were significantly lower than the controls (47, 36, and 19% inhibition, respectively). The influence on the same parameters for yellow nutsedge (35, 21, and 43% inhibition, respectively) were not significantly different from purple nutsedge. Sweet potato shoot dry weight was inhibited by purple and yellow nutsedge by 42% and 45%, respectively. The major allelopathic substance from ‘Regal’ root periderm tissue was isolated and tested in vitro on the two sedges. The I50's for shoot growth, root number, and root length were 118, 62, and 44 μg/ml, respectively, for yellow nutsedge. The I50's for root number and root length were 91 and 85 μg/ml, respectively, for purple nutsedge and the I50for shoot growth could not be calculated.


1993 ◽  
Vol 7 (4) ◽  
pp. 900-905 ◽  
Author(s):  
John S. Richburg ◽  
John W. Wilcut ◽  
Glenn R. Wehtje

Greenhouse studies were conducted to determine the response of purple and yellow nutsedges to selective soil placement of 5 cm of soil treated with imazethapyr above and/or below the nutsedge tubers. Early postemergence (EPOST) or postemergence (POST) imazethapyr treatments at 71 g ai/ha as a foliar, soil, or foliar + soil application was also evaluated. Imazethapyr placement above or below the nutsedge tuber generally increased shoot number, shoot dry weight (SW), shoot regrowth dry weight (SRW), and root tuber dry weight (RTW) production in both species, 28 and 42 days after treatment (DAT) compared with the control. However, the 5-cm above + 5-cm below tuber treatment at 14, 28, and 42 DAT reduced purple nutsedge shoot number, SW, SRW, and RTW to 19, 7, 14, and 26% of the control, respectively. Yellow nutsedge shoot number was 103% of the control with the 5-cm above + 5-cm below tuber treatment 42 DAT. The 5-cm above + 5-cm below tuber treatment reduced yellow nutsedge SW, SRW, and RTW to 43, 44, and 23% of the control, respectively, 28 and 42 DAT. EPOST and POST foliar + soil and soil-only applications reduced SW 28 d after treatment (DAT) to 13% or less of the control for both species. SRWs of both species were ≤ 53% of the control 42 DAT for the soil-only application. The foliar-only treatment was the least effective in SW, SRW, and RTW reductions.


Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 111-115 ◽  
Author(s):  
John W. Wilcut

Greenhouse studies were conducted to determine purple and yellow nutsedge response to selective placement of a 5-cm layer of pyrithiobac sodium-treated soil above, below, or above and below nutsedge tubers. Pyrithiobac sodium at 36 or 72 g ae ha−1applied postemergence as foliar, soil, or foliar and soil treatments also was evaluated. Pyrithiobac sodium applied above, below, or above and below nutsedge tubers reduced yellow and purple nutsedge shoot number, shoot regrowth, and root-tuber dry weight at least 90%. Foliar-only treatment of pyrithiobac sodium was less effective at reducing emerged purple and yellow nutsedge numbers than application to soil only or to foliage and soil. Best reduction in yellow and purple nutsedge growth with pyrithiobac sodium was obtained with soil-incorporated treatments.


Weed Science ◽  
1994 ◽  
Vol 42 (3) ◽  
pp. 398-402 ◽  
Author(s):  
John S. Richburg ◽  
John W. Wilcut ◽  
Glenn R. Wehtje

Greenhouse studies were conducted to determine the response of purple and yellow nutsedge to selective placement of 5 cm of soil treated with AC 263,222 above and/or below nutsedge tubers. AC 263,222 applied early POST (EPOST) or POST at 71 g ai ha-1as a foliar, soil, or foliar + soil application also was evaluated. AC 263,222 applied below nutsedge tubers did not reduce purple or yellow nutsedge shoot number, shoot dry weight, shoot regrowth dry weight, or root-tuber dry weight. However, when it was applied above purple nutsedge tubers, shoot dry weight was reduced; and when it was applied above yellow nutsedge tubers, shoot dry weight and root dry weight were reduced. AC 263,222 applied 5 cm above + 5 cm below purple nutsedge tubers reduced shoot number, shoot dry weight, shoot regrowth dry weight, and root dry weight to 9, 4, 10, and 16% of the control, respectively, in purple nutsedge and to 23, 16, 9, and 15% of the control, respectively, in yellow nutsedge. AC 263,222 applied EPOST or POST reduced shoot dry weight, shoot regrowth dry weight, and root dry weight of purple nutsedge to less than or equal to 11, 7, and 27% of the control, respectively, and to less than or equal to 10, 16, and 29% of the control, respectively, for yellow nutsedge with no differences between application methods. The foliar and soil activity of AC 263,222 for purple and yellow nutsedge control provides an advantage over currently registered peanut herbicides.


Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 707-712 ◽  
Author(s):  
Krishna N. Reddy ◽  
Leo E. Bendixen

Greenhouse and laboratory experiments were conducted to study the activity of foliar-applied chlorimuron in yellow and purple nutsedge. Foliar-applied chlorimuron caused injury to both yellow and purple nutsedge at rates as low as 5 g ai/ha. Visible injury increased as rates increased from 5 to 20 g/ha at all weekly evaluation dates. At 28 days after application, there was 84% control of yellow and 100% control of purple nutsedge from 20 g/ha of chlorimuron. In both species, all rates of chlorimuron reduced shoot dry weight, inhibited secondary shoot production, and inhibited resprouting of parent tubers attached to treated plants. Over 92% of the applied label was recovered, when 15 μl of 3.46 mM14C-chlorimuron solution containing 0.18 μCi was applied to a 1 cm2area in the middle of the fourth fully expanded leaf. Over 12% of the total14C applied was absorbed, with over 15% of that being translocated within 1 day after application in both species. More than 76% of the absorbed14C in yellow nutsedge and 72% in purple nutsedge remained in the treated area. In both species, basipetal transport was limited. Analysis of plant tissue extracts by thin-layer chromatography indicated slow degradation of chlorimuron in both species. Susceptibility of yellow and purple nutsedge to chlorimuron appears to be due to the rapid absorption and translocation rates in relationship to the slow degradation rate of the active parent compound.


1995 ◽  
Vol 9 (1) ◽  
pp. 148-152 ◽  
Author(s):  
William K. Vencill ◽  
John S. Richburg ◽  
John W. Wilcut ◽  
Larry R. Hawf

Greenhouse studies were conducted to determine the response of purple and yellow nutsedge to selective soil placement of 5 cm of soil treated with MON-12037 above and/or below the nutsedge tubers. MON-12037 at 53 g/ai ha applied as a foliar, soil, or foliar + soil application also were evaluated. MON-12037 placement above, below, or above + below the nutsedge tuber decreased shoot number, shoot dry weight, shoot regrowth dry weight, and root-tuber dry weight production in both species, 30 and 60 d after treatment. MON-12037 applied as a foliar, soil, and foliar + soil treatment was effective in reducing purple nutsedge shoot regrowth dry weight to less than 5% of the non-treated control. Yellow nutsedge shoot regrowth dry weight from the foliar + soil and soil-only applications was less than 1% of the non-treated control.


Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 389-398
Author(s):  
Parsa Tehranchian ◽  
Jason K. Norsworthy ◽  
Matheus Palhano ◽  
Nicholas E. Korres ◽  
Scott McElroy ◽  
...  

A yellow nutsedge biotype (Res) from an Arkansas rice field has evolved resistance to acetolactate synthase (ALS)-inhibiting herbicides. TheResbiotype previously exhibited cross-resistance to ALS inhibitors from four chemical families (imidazolinone, pyrimidinyl benzoate, sulfonylurea, and triazolopyrimidine). Experiments were conducted to evaluate alternative herbicides (i.e., glyphosate, bentazon, propanil, quinclorac, and 2,4-D) currently labeled in Arkansas rice–soybean production systems. Based on the percentage of aboveground dry weight reduction, control of the yellow nutsedge biotypes with the labeled rate of bentazon, propanil, quinclorac, and 2,4-D was < 44%. Glyphosate (867 g ae ha−1) resulted in 68 and > 94% control of theResand susceptible yellow nutsedge biotypes, respectively, at 28 d after treatment. Dose-response studies were conducted to estimate the efficacy of glyphosate on theResbiotype, three susceptible yellow nutsedge biotypes, and purple nutsedge. Based on the dry weights, theResbiotype was ≥ 5- and ≥ 1.3-fold less responsive to glyphosate compared to the susceptible biotypes and purple nutsedge, respectively. Differences in absorption and translocation of radiolabeled glyphosate were observed among the yellow nutsedge biotypes and purple nutsedge. The susceptible biotype had less14C-glyphosate radioactivity in the tissues above the treated leaf and greater radioactivity in tissues below the treated leaf compared to theResbiotype and purple nutsedge. Reduced translocation of glyphosate in tissues below the treated leaf of theResbiotype could be a reason for the lower glyphosate efficacy in theResbiotype. No amino acid substitution that would correspond to glyphosate resistance was found in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene of theResbiotype. However, an amino acid (serine) addition was detected in the EPSPS gene of theResbiotype; albeit, it is not believed that this addition contributes to lower efficacy of glyphosate in this biotype.


2011 ◽  
Vol 29 (4) ◽  
pp. 220-222
Author(s):  
Kathryne J. Jernigan ◽  
Amy N. Wright

Abstract Research was conducted to screen four landscape shrub taxa for tolerance to repeated flooding events. Plants of Fothergilla × intermedia ‘Mt. Airy’ (dwarf witchalder), Ilex verticillata ‘Winter Red’ (winterberry), Clethra alnifolia ‘Ruby Spice’ (summersweet), and Viburnum nudum Brandywine™ (possumhaw) were flooded repeatedly over six weeks for 0 (non-flooded), 3, or 6 days with a draining period of 6 days between each flooding event. The experiment was repeated for a total of two runs. With the exception of F. × intermedia ‘Mt. Airy’, all taxa showed good visual quality and no reduction in root growth in either run, and effects on shoot growth were minimal. Size index of Clethra alnifolia ‘Ruby Spice’ was 27% higher in plants flooded for 0 or 3 days than in plants flooded for 6 days in run 1 only. Shoot dry weight of Ilex verticillata ‘Winter Red’ was actually 11% higher in plants flooded 6 days days than in plants flooded for 0 or 3 days in run 2. Size index of Viburnum nudum Brandywine™ increased with increasing flood length, and plants flooded for 6 days had a 9% higher SI than plants flooded for 0 days in run 1. With the exception of Fothergilla × intermedia L. ‘Mt. Airy’, all taxa appeared tolerant of and even thrived during flooding and would be appropriate shrub selections for a southeastern United States rain garden.


2001 ◽  
Vol 19 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Wallace G. Pill ◽  
James A. Gunter

Abstract This study was conducted to determine whether treating seeds of ‘Sensation Mixed’ cosmos (Cosmos bipinnatus Cav.) and ‘Bonanza Gold’ marigold (Tagetes patula L.) with paclobutrazol (PB) could suppress seedling growth. Seeds were soaked in solutions of 0, 500 or 1000 mg PB/liter (ppm PB) for 16 hours at 25C (77F) or they were primed [−0.5 MPa (−5 bars) for 7 days at 20C (68F)] in Grade 5 exfoliated vermiculite moistened with 0, 500 or 1000 ppm PB solltuions. Soaked and primed seeds were dried for 1 day at 19C (65F) and 25% relative humidity. These seeds and control (non-treated) seeds were sown into plug cells containing peat-lite. Increasing PB concentration decreased cosmos shoot height at 32 days after planting (DAP), but decreased emergence percentage, responses that were more pronounced with priming than with soaking. A 1 ppm PB growth medium drench [30 ml/cell(0.2 mg PB/cell)] and, to a greater extent a 10 mg PB/liter (ppm PB) shoot spray [2 ml/shoot (0.02 mg PB/shoot)], both applied at 10 DAP, resulted in greater cosmos shoot height suppression at 32 DAP than treatment of seeds with 1000 ppm PB. Soaking marigold seeds in 1000 ppm PB failed to decrease shoot height below those of plants from non-treated seeds at 32 DAP. However, exposure to 1000 ppm PB during priming of marigold seeds resulted in a similar shoot height suppression (13%) as the growth medium drench, and similar shoot dry weight reduction (21%) as the shoot spray. Suppression of shoot growth by this seed treatment was short-term since by five weeks after transplanting into 15 cm (6 in) pots, only marigold plants that had received the growth medium drench or shoot spray were smaller than those of control plants. Treating marigold seeds with 1000 mg ppm PB used about one-fifth the PB used to drench the growth medium.


2015 ◽  
Vol 33 (3) ◽  
pp. 137-141
Author(s):  
Bruce R. Roberts ◽  
Chris Wolverton ◽  
Samantha West

The efficacy of treating soilless substrate with a commercial humectant was tested as a means of suppressing drought stress in 4-week-old container-grown Zinnia elegans Jacq. ‘Thumbelina’. The humectant was applied as a substrate amendment at concentrations of 0.0, 0.8, 1.6 and 3.2% by volume prior to withholding irrigation. An untreated, well-watered control was also included. The substrate of treated plants was allowed to dry until the foliage wilted, at which time the plants were harvested and the following measurements taken: number of days to wilt (DTW), xylem water potential (ψx), shoot growth (shoot dry weight, leaf area) and root growth (length, diameter, surface area, volume, dry weight). For drought-stressed plants grown in humectant-treated substrate at concentrations of 1.6 and 3.2%, DTW increased 25 and 33%, respectively. A linear decrease in ψx was observed as the concentration of humectant increased from 0.0 to 3.2%. Linear trends were also noted for both volumetric moisture content (positive) and evapotranspiration (negative) as the concentration of humectant increased. For non-irrigated, untreated plants, stress inhibited shoot growth more than root growth, resulting in a lower root:shoot ratio. For non-irrigated, humectant-treated plants, the length of fine, water-absorbing roots increased linearly as humectant concentration increased from 0.0 to 3.2%. Using humectant-amended substrates may be a management option for mitigating the symptoms of drought stress during the production of container-grown bedding plants such as Z. elegans.


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