Interaction of Glyphosate and Pelargonic Acid in Ready-to-Use Weed Control Products

2009 ◽  
Vol 23 (4) ◽  
pp. 544-549 ◽  
Author(s):  
Glenn Wehtje ◽  
James E. Altland ◽  
Charles H. Gilliam
Keyword(s):  
Weed Control ◽  
Pelargonic Acid ◽  
Control Efficacy ◽  
Yellow Nutsedge ◽  
Greenhouse Experiments ◽  
Equal Rate ◽  
Early Injury ◽  
And Control ◽  
Large Crabgrass

Glyphosate-based, ready-to-use weed control products often contain pelargonic acid (PA) at a concentration equivalent to that of the glyphosate. It remains unclear what benefit, if any, this combination provides. Greenhouse experiments using large crabgrass, yellow nutsedge, longstalked phyllanthus, and prostrate spurge were conducted to determine whether the addition of PA improved weed control efficacy compared to glyphosate alone. Glyphosate was applied at a series of rates, ranging from 0.11 to 1.12 kg ae/ha, either alone or with an equal rate of PA. Addition of PA to glyphosate was synergistic only in longstalked phyllanthus and yellow nutsedge, and this synergism was manifested only as an increase in the amount of early (i.e., 5 to 7 d after treatment) visual injury. Conversely, longer-term control and control of regrowth was either not affected or reduced by the addition of PA. We conclude that the addition of PA to glyphosate in ready-to-use weed control products is neither warranted nor justified. However, we also note that the increase in early injury that was observed in only two of the four species evaluated could be an important attribute for the consumers for which these products are targeted.

Weed Control Using an Enclosed Thermal Heating Apparatus

2012 ◽  
Vol 26 (4) ◽  
pp. 699-707 ◽  
Author(s):  
Jared A. Hoyle ◽  
J. Scott McElroy ◽  
J. Jack Rose
Keyword(s):  
Weed Control ◽  
Field Research ◽  
Control Treatment ◽  
Thermal Treatments ◽  
Application Timing ◽  
Yellow Nutsedge ◽  
Virginia Buttonweed ◽  
Turfgrass Establishment ◽  
Fall Application ◽  
Large Crabgrass

Weed control by heat or flaming typically uses flames to burn small weeds, directed away from desired crops. This research studied an enclosed flaming system for weed control before turfgrass establishment. Field research trials were conducted to explore the efficacy of a PL-8750 flame sanitizer at two application timings. Treatments included various application methods of PL-8750 flame sanitizer and common thermal and chemical weed control methods. Data were weed control relative to the control treatment. Species evaluated included carpetweed, Virginia buttonweed, spotted spurge, large crabgrass, goosegrass, old world diamond-flower, cocks-comb kyllinga, and yellow nutsedge. Turfgrass establishment was not successful in summer but was successful in fall. Fall-application timing trials resulted in > 60% tall fescue establishment at 6 wk after seeding (WAS) for all treatments. Summer-application timing trials resulted in unacceptable turfgrass establishment (≤ 18%) for all evaluated turfgrass species at 6 WAS. Broadleaf and grassy weeds were better controlled compared with sedge weeds. Overall, solarization; covered, emerged-weed flaming; and double applications of covered, emerged-weed flaming were the most successful treatments. Solarization controlled carpetweed, Virginia buttonweed, spotted spurge, large crabgrass, and goosegrass > 80% at 6 WAS. Weed control across thermal treatments were equal to or greater than the comparison chemical treatment (dazomet at 389 kg ha−1). Results indicate thermal weed control has potential for reducing weed populations before turfgrass establishment.

Integration of a Brassicaceae Cover Crop with Herbicides in Plasticulture Tomato

2009 ◽  
Vol 23 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Sanjeev K. Bangarwa ◽  
Jason K. Norsworthy ◽  
Edward E. Gbur
Keyword(s):  
Weed Control ◽  
Cover Crop ◽  
Fruit Yield ◽  
Palmer Amaranth ◽  
Marketable Yield ◽  
Purple Nutsedge ◽  
Yellow Nutsedge ◽  
Full Rate ◽  
Over The Top ◽  
Large Crabgrass

Weeds are a major constraint in tomato production, especially in the absence of methyl bromide. Field trials were conducted in 2006 and 2007 to evaluate the integrated use of a mustard ‘Caliente’ (a blend of brown and white mustard) cover crop with one-half and full rate PRE/POST herbicides for weed control and crop response in polyethylene-mulched tomato. Caliente was flail mowed and incorporated into the soil prior to forming beds. PRE herbicides were applied under polyethylene mulch, and POST herbicides were sprayed over the top of tomato. Full rates for S-metolachlor, halosulfuron, and trifloxysulfuron were 1,600, 27, and 7.9 g ai/ha, respectively. Caliente had no effect on weed control or tomato injury and yield. Except for large crabgrass control and tomato injury and yield, only the main effect of herbicide selection and application rate affected these parameters. Tomato injury was minimal (< 6%) from PRE- and POST-applied herbicides. S-metolachlor applied PRE provided 66% purple nutsedge, 67% yellow nutsedge, and 77% Palmer amaranth control at 4 wk after transplanting (WATP). S-metolachlor–treated plots at the full rate produced the highest marketable fruit yield among herbicide treatments, with jumbo fruit yield equivalent to the hand-weeded treatment. Trifloxysulfuron was the best POST-applied herbicide based on marketable yield and weed control. POST-applied trifloxysulfuron provided 41% purple nutsedge, 58% yellow nutsedge, and 55% Palmer amaranth control at 8 to 9 WATP. Halosulfuron applied PRE controlled purple and yellow nutsedge 70 and 78%, respectively, at 4 WATP, and POST-applied halosulfuron controlled purple nutsedge 74% and yellow nutsedge 78% at 8 to 9 WATP. Halosulfuron applied either PRE or POST failed to control Palmer amaranth and large crabgrass. Greater weed control and marketable tomato yield were achieved with full rates of herbicides. This research demonstrates no additional advantage of Caliente mustard when used with herbicides in tomato. None of the PRE or POST herbicides applied alone were sufficient to maintain season-long, broad-spectrum weed control and optimum marketable yield in tomato. Therefore, integration of PRE and POST herbicides at full rates is suggested.

Weed Management in Peanut with Herbicide Combinations Containing Imazapic and Other Pesticides

2009 ◽  
Vol 23 (1) ◽  
pp. 6-10 ◽  
Author(s):  
David L. Jordan ◽  
Sarah H. Lancaster ◽  
James E. Lanier ◽  
Bridget R. Lassiter ◽  
P. Dewayne Johnson
Keyword(s):  
North Carolina ◽  
Weed Control ◽  
Weed Management ◽  
Common Ragweed ◽  
Common Lambsquarters ◽  
Yellow Nutsedge ◽  
Pod Yield ◽  
Final Experiment ◽  
Pitted Morningglory ◽  
Large Crabgrass

Research was conducted in North Carolina to compare weed control by various rates of imazapic POST alone or following diclosulam PRE. In a second experiment, weed control by imazapic applied POST alone or with acifluoren, diclosulam, or 2,4-DB was compared. In a final experiment, yellow nutsedge control by imazapic alone and with the fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole was compared. Large crabgrass was controlled more effectively by imazapic POST than diclosulam PRE. Common lambsquarters, common ragweed, and eclipta were controlled more effectively by diclosulam PRE than imazapic POST. Nodding spurge was controlled similarly by both herbicides. Few differences in control were noted when comparing imazapic rates after diclosulam PRE. Applying either diclosulam PRE or imazapic POST alone or in combination increased peanut yield over nontreated peanut in five of six experiments. Few differences in pod yield were noted when comparing imazapic rates. Acifluorfen, diclosulam, and 2,4-DB did not affect entireleaf morningglory, large crabgrass, nodding spurge, pitted morningglory, and yellow nutsedge control by imazapic. Eclipta control by coapplication of imazapic and diclosulam exceeded control by imazapic alone. The fungicides azoxystrobin, chlorothalonil, pyraclostrobin, and tebuconazole did not affect yellow nutsedge control by imazapic.

scholarly journals Weed Control with Landscape Fabrics

1989 ◽  
Vol 7 (4) ◽  
pp. 129-133 ◽  
Author(s):  
Jeffrey F. Derr ◽  
Bonnie Lee Appleton
Keyword(s):  
Field Study ◽  
Weed Control ◽  
Cyperus Esculentus ◽  
Digitaria Sanguinalis ◽  
Yellow Nutsedge ◽  
Black Plastic ◽  
Hand Weeding ◽  
Preemergence Herbicides ◽  
Large Crabgrass

Abstract Six polypropylene landscape fabrics were compared with black plastic and preemergence herbicides for weed control. Large crabgrass [Digitaria sanguinalis (L.) Scop.] shoots and roots and yellow nutsedge (Cyperus esculentus L.) shoots penetrated all of the fabrics tested and developed into large plants. In greenhouse studies, black plastic plus mulch, and pennant (metolachlor) [2-chloro-N-(2ethyl-6-methylphenyl)-N-(methoxy-1-methylethyl)acetamide] at 4.5 kg ai/ha (4.0 lb/A) plus mulch provided equal, or greater control of large crabgrass than the landscape fabrics. In the field study, more time was required to hand-weed landscape fabrics covered with mulch than uncovered fabrics. When covered with mulch, hand-weeding time and weed shoot fresh weights were similar for black plastic, surflan (oryzalin) [4-(dipropylamino)-3,5-dinitrobenzenesulfonamide] at 2.2 kg/ha (2.0 lb/A), and the landscape fabrics.

scholarly journals Weed Control in Sweet Bell Pepper Using Sequential Postdirected Applications of Pelargonic Acid

2014 ◽  
Vol 24 (6) ◽  
pp. 663-667 ◽  
Author(s):  
Charles L. Webber ◽  
Merritt J. Taylor ◽  
James W. Shrefler
Keyword(s):  
Weed Control ◽  
Sweet Pepper ◽  
Application Rate ◽  
Bell Pepper ◽  
Pelargonic Acid ◽  
Yellow Nutsedge ◽  
Crop Injury ◽  
Application Rates ◽  
Control Research ◽  
The Impact

Pepper (Capsicum annuum) producers would benefit from additional herbicide options that are safe to the crop and provide effective weed control. Research was conducted in southeastern Oklahoma (Atoka County, Lane, OK) during 2010 and 2011 to determine the impact of pelargonic acid on weed control efficacy, crop injury, and pepper yields. The experiment included pelargonic acid applied unshielded postdirected at 5, 10, and 15 lb/acre, plus an untreated weedy control and an untreated weed-free control. ‘Jupiter’ sweet bell pepper, a tobacco mosaic virus-resistant sweet pepper with a 70-day maturity, was transplanted into single rows on 3-ft centered raised beds with 18 inches between plants (9680 plants/acre) on 28 May 2010 and 27 May 2011, respectively. Weeds included smooth crabgrass (Digitaria ischaemum), cutleaf groundcherry (Physalis angulata), spiny amaranth (Amaranthus spinosus), and yellow nutsedge (Cyperus esculentus). Pelargonic acid was applied postdirected each year in mid-June and then reapplied 8 days later. The 15-lb/acre pelargonic acid treatment resulted in the maximum smooth crabgrass control (56%) and broadleaf weed control (66%) at 1 day after the initial spray treatment (DAIT), and 33% yellow nutsedge control at 3 DAIT. Pelargonic acid at 15 lb/acre provided equal or slightly greater smooth crabgrass and broadleaf (cutleaf groundcherry and spiny amaranth) control compared with the 10-lb/acre application, and consistently greater control than the 5-lb/acre rate and the weedy control. Pelargonic acid was less effective at controlling yellow nutsedge than smooth crabgrass and broadleaf weeds. As the rate of pelargonic acid increased from 5 to 15 lb/acre, yellow nutsedge control also increased significantly for all observation dates. Increasing the pelargonic acid application rate increased the crop injury rating. The maximum crop injury occurred for each application rate at 1 DAIT with 7%, 8.0%, and 13.8% injury for pelargonic acid rates 5, 10, and 15 lb/acre, respectively. There was little or no new crop injury after the second postdirected application of pelargonic acid and crop injury following 3 DAIT for application rates was 2% or less. Only the 15-lb/acre pelargonic acid application produced greater fruit per hectare (4784 fruit/ha) and yields (58.65 kg·ha−1) than the weedy control (1196 fruit/ha and 19.59 kg·ha−1). The weed-free yields (7176 fruit/ha, 178.11 kg·ha−1, and 24.82 g/fruit) were significantly greater than all pelargonic acid treatments and the weedy control. Pelargonic acid provided unsatisfactory weed control for all rates and did not significantly benefit from the sequential applications. The authors suggest the pelargonic acid be applied to smaller weeds to increase the weed control to acceptable levels (>80%).

Interference and Control of Large Crabgrass (Digitaria sanguinalis) and Southern Sandbur (Cenchrus echinatus) in Forage Bermudagrass (Cynodon dactylon)

1998 ◽  
Vol 12 (4) ◽  
pp. 707-711 ◽  
Author(s):  
Robert H. Walker ◽  
Glenn Wehtje ◽  
John S. Richburg
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Cynodon Dactylon ◽  
Ground Cover ◽  
Weed Competition ◽  
Minor Importance ◽  
Digitaria Sanguinalis ◽  
Competitive Species ◽  
And Control ◽  
Large Crabgrass

Field experiments were conducted at two locations in central Alabama to evaluate competitiveness of large crabgrass and southern sandbur with ‘Tifton 78’ hybrid bermudagrass as influenced by diuron application and sprigging rate. Large crabgrass was the more competitive species. In late season, bermudagrass ground cover with no weed competition was 96% compared with 72 and 81% where large crabgrass and southern sandbur, respectively, were present. Similarly, large crabgrass and southern sandbur reduced the proportion of bermudagrass in the cumulative harvested forage by at least 59 and 38%, respectively. Application of diuron preemergence (PRE) at 1.1 kg ai/ha was more effective than postemergence (POST) application, both in terms of weed control and bermudagrass safety. With diuron applied PRE, large crabgrass and southern sandbur reduced the proportion of bermudagrass in the harvested forage only 32 and 25%, respectively. Increasing bermudagrass sprigging rate was beneficial for weed control but of relatively minor importance compared with diuron PRE.

Cultivation and Herbicides for Weed Control in Sweet Potato (Ipomoea batatas)

1990 ◽  
Vol 4 (3) ◽  
pp. 518-523 ◽  
Author(s):  
Norman C. Glaze ◽  
Melvin R. Hall
Keyword(s):  
Weed Control ◽  
Sweet Potato ◽  
Ipomoea Batatas ◽  
Late Season ◽  
Yellow Nutsedge ◽  
Herbicide Treatment ◽  
Large Crabgrass

Alachlor, chloramben, cinmethylin, diphenamid, fluazifop, fluazifop-P, metolachlor, metribuzin, napropamide, oryzalin, and sethoxydim were applied on transplanted sweet potato at Tifton, GA, during 1982 to 1985. The weeds most prevalent were large crabgrass, Florida pusley, smallflower morningglory, and yellow nutsedge. No significant phytotoxicity was observed from any herbicide treatment over the 4 yr. Cultivation at 4 wk is advantageous to eliminate early flushes of weeds which escape control and reform the beds. Alachlor or metolachlor at 4.5 and 3.4 kg ha-1, respectively, and metribuzin controlled weeds best. Although no serious phytotoxicity was evident, these treatments tended to cause lowered yields of marketable roots while marginally affecting total yields in most cases. Metribuzin was the only compound which controlled late-season broadleaf weeds such as smallflower morningglory effectively.

Use of F6285 for Weed Control in Peanut: Efficacy and Crop Injury1,2

1994 ◽  
Vol 21 (1) ◽  
pp. 65-68 ◽  
Author(s):  
W. Carroll Johnson ◽  
Benjamin G. Mullinix
Keyword(s):  
Weed Control ◽  
Field Studies ◽  
Severely Injured ◽  
Control Efficacy ◽  
Late Season ◽  
Yellow Nutsedge ◽  
Crop Injury

Abstract Field studies in 1991 and 1992 at Tifton and Attapulgus, GA evaluated the weed control efficacy and crop safety of F6285 on peanut. Treated peanut were stunted by F6285 and had chlorotic leaflet margins. The degree and persistence of injury varied according to rate of F6285. The lowest rate of F6285 (0.14 kg ai ha-1) produced the aforementioned symptoms early in the season, but peanut recovered by late season with no yield effects (P≤0.05). F6285 at 0.28 and 0.42 kg ha-1 severely injured peanut and reduced yields. Preemergence and vegetative emergence applications of F6285 were equally injurious. F6285 effectively controlled yellow nutsedge at rates as low as 0.14 kg ha-1, but sicklepod was not controlled at rates up to 0.42 kg ha-1. F6285 controlled yellow nutsedge more effectively that standard treatments of metolachlor or imazethapyr, but crop injury from F6285 was greater (P≤0.05) than from other herbicides.

Allyl Isothiocyanate and Metham Sodium as Methyl Bromide Alternatives for Weed Control in Plasticulture Tomato

2014 ◽  
Vol 28 (2) ◽  
pp. 377-384 ◽  
Author(s):  
Pratap Devkota ◽  
Jason K. Norsworthy
Keyword(s):  
Weed Control ◽  
Methyl Bromide ◽  
Allyl Isothiocyanate ◽  
Palmer Amaranth ◽  
Tomato Production ◽  
Tomato Plants ◽  
Yellow Nutsedge ◽  
Tomato Yield ◽  
Metham Sodium ◽  
Large Crabgrass

Isothiocyanates (ITCs) were evaluated as an alternative to methyl bromide (MeBr) for control of Palmer amaranth, large crabgrass, and yellow nutsedge; reduction of tuber density; and increase in marketable tomato yield in low density polyethylene (LDPE)-mulched tomato production. Allyl ITC was applied at 450, 600, and 750 kg ai ha−1; metham sodium (methyl ITC generator) was applied at 180, 270, and 360 kg ai ha−1; and MeBr plus chloropicrin (mixture of MeBr and chloropicrin at 67 : 33%, respectively) was applied at 390 kg ai ha−1. A nontreated weedy check was included for comparison. There was no injury to tomato plants following allyl ITC, metham sodium, or MeBr application. Allyl ITC at 750 kg ha−1or metham sodium at 360 kg ha−1controlled Palmer amaranth ≥ 79%, large crabgrass ≥ 76%, and yellow nutsedge ≥ 80% and was comparable to the weed control with MeBr. Highest rates of allyl ITC and metham sodium reduced yellow nutsedge tuber density (≤ 76 tubers m−2) comparable to the MeBr application. Total marketable tomato yield was ≥ 31.6 t ha−1in plots treated with allyl ITC at 750 kg ha−1or metham sodium at 360 kg ha−1. Marketable tomato yield from the highest rate of allyl ITC or metham sodium were similar to the yield (38.2 t ha−1) with MeBr treatment. Therefore, allyl ITC at 750 kg ha−1and metham sodium at 360 kg ha−1are effective alternatives to MeBr for Palmer amaranth, large crabgrass, and yellow nutsedge control in LDPE-mulched tomato.

scholarly journals Pelargonic Acid for Weed Control in Organic Vidalia® Sweet Onion Production

2014 ◽  
Vol 24 (6) ◽  
pp. 696-701 ◽  
Author(s):  
Wiley Carroll Johnson ◽  
Jerry W. Davis
Keyword(s):  
Weed Control ◽  
Winter Season ◽  
Field Trials ◽  
Pelargonic Acid ◽  
Yield Response ◽  
Clove Oil ◽  
Cool Season ◽  
Control Efficacy ◽  
Natural Sources ◽  
Main Effects

Cultivation using a tine weeder is a proven means to manage weeds in organic Vidalia® sweet onion (Allium cepa) production. If the initial cultivation is delayed, emerged weeds are not controlled. In these cases, herbicides derived from natural products could be used to control the emerged weeds before the initial cultivation. Clove oil has been evaluated for this use, but cool-season weed control is inconsistent during the winter season when Vidalia® sweet onion are grown. Pelargonic acid is a herbicide that can be derived from natural sources or synthesized. Field trials were conducted from 2011 through 2013 to determine the efficacy of pelargonic acid for cool-season weed control in organic Vidalia® sweet onion. All possible combinations of four herbicides and three cultivation regimes using a tine weeder were evaluated. Herbicides evaluated were pelargonic acid (3% and 5% by vol.), clove oil [10% by vol. (2011 and 2012)], d-limonene [14% (2013 only)], and a nontreated control. Cultivation regimes were twice (2×) and four times (4×) at 2-week intervals, and a noncultivated control. Main effects of cultivation and herbicides were independent for all parameters, with no improvement when used in combination. Cultivation 2× and 4× controlled cool-season weeds and improved onion yields, which is consistent with previous research. Pelargonic acid (5%) controlled weeds similar to clove oil (2011 and 2012) and d-limonene (2013), with cool-season weed control efficacy being inconsistent among all herbicides. Onion yield response to weed control from any of the herbicides, including pelargonic acid, also was inconsistent. In organic onion production, inconsistent cool-season performance using pelargonic acid is similar to other herbicides derived from natural sources.

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