scholarly journals Cover Crop and Herbicide Combinations for Weed Control in Polyethylene-mulched Bell Pepper

2009 ◽  
Vol 19 (2) ◽  
pp. 405-410 ◽  
Author(s):  
Sanjeev K. Bangarwa ◽  
Jason K. Norsworthy ◽  
Edward E. Gbur

Field trials were conducted in 2006 and 2007 to evaluate the performance of ‘Caliente’ mustard cover crop and herbicide combinations for weed control in polyethylene-mulched bell pepper (Capsicum annuum). ‘Caliente’ mustard is a blend of brown mustard (Brassica juncea) and white mustard (Sinapis alba). Herbicide treatments included 1/2× and 1× rates of two pre-emergence (PRE) and two postdirected (PD) herbicides. PRE herbicides were applied 1 week before transplanting, whereas PD herbicides were applied at 4 to 5 weeks after transplanting. ‘Caliente’ mustard did not supplement weed control or improve bell pepper yield in herbicide-treated plots. There was a significant herbicide selection by application rate interaction for large crabgrass (Digitaria sanguinalis) control and bell pepper yield, but only the main effect of herbicide selection and application rate affected the control of purple nutsedge (Cyperus rotundus), yellow nutsedge (Cyperus esculentus), and palmer amaranth (Amaranthus palmeri). Bell pepper injury was not more than 9% from all herbicides and application rates. Except for large crabgrass, control of all weed species improved by increasing the application rate from 1/2× to 1×. S-metolachlor PRE provided more broad-spectrum weed control than other herbicides. Halosulfuron applied PRE or PD was selective to purple nutsedge and yellow nutsedge, whereas trifloxysulfuron performed better than halosulfuron on palmer amaranth and large crabgrass. Plots treated with the 1× rate of S-metolachlor or trifloxysulfuron produced the highest marketable bell pepper yield among the herbicide treatments, but no herbicide treatment allowed for marketable yield equivalent to the weed-free treatment.

2009 ◽  
Vol 23 (2) ◽  
pp. 280-286 ◽  
Author(s):  
Sanjeev K. Bangarwa ◽  
Jason K. Norsworthy ◽  
Edward E. Gbur

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.


2012 ◽  
Vol 26 (4) ◽  
pp. 763-768 ◽  
Author(s):  
Sanjeev K. Bangarwa ◽  
Jason K. Norsworthy ◽  
Edward E. Gbur

Methyl bromide is a common fumigant for effective weed control in polyethylene-mulched vegetable crops. However, the ban on methyl bromide in the United States has created a need to find a suitable alternative. This study investigated the herbicidal efficacy of phenyl isothiocyanate (ITC) as a methyl bromide alternative for weed control in polyethylene-mulched bell pepper during 2006 and 2007. Six rates of phenyl ITC (0, 15, 75, 150, 750, 1,500 kg ha−1) under low-density polyethylene (LDPE) or virtually impermeable film (VIF) mulch were tested against yellow nutsedge, Palmer amaranth, and large crabgrass. Additionally, a standard treatment of methyl bromide/chloropicrin (67 : 33%) at 390 kg ha−1under LDPE mulch was included for comparison. VIF mulch provided no advantage over LDPE mulch in either improving weed control or marketable yield in bell pepper. Unacceptable pepper injury (≥ 60%) occurred at the highest phenyl ITC rate of 1,500 kg ha−1at 2 WATP in both years, regardless of mulch type. Higher bell pepper injury was observed in 2006 (≥ 36%) than in 2007 (≤ 11%) at 750 kg ha−1of phenyl ITC. The lower injury in 2007 could be attributed to aeration of beds 48 h prior to transplanting. Regardless of mulch type, phenyl ITC at 2,071 (± 197) and 1,655 (± 309) kg ha−1was required to control yellow nutsedge, Palmer amaranth, and large crabgrass equivalent to methyl bromide in 2006 and 2007, respectively. Bell pepper marketable yield at all rates of phenyl ITC was lower than methyl bromide in 2006. In contrast, marketable yield in phenyl ITC at 750–kg ha−1was equivalent to methyl bromide in 2007. It is concluded that phenyl ITC should be applied at least 4.2 times higher rate than methyl bromide for effective weed control, and bed aeration is required to minimize crop injury and yield loss. Additional research is needed to test phenyl ITC in combination with other weed control strategies to obtain effective weed control with acceptable crop safety.


2013 ◽  
Vol 27 (3) ◽  
pp. 468-474 ◽  
Author(s):  
Pratap Devkota ◽  
Jason K. Norsworthy ◽  
Ronald Rainey

Methyl bromide (MeBr), classified as a Class I ozone-depleting substance, has been banned for ordinary agricultural uses. Weed control in commercial bell pepper production is complicated by the ban on MeBr and the lack of other available and effective soil fumigants. A field study was conducted to evaluate the effectiveness of allyl isothiocyanate (ITC) and metam sodium (methyl ITC generator) as MeBr alternatives for control of Palmer amaranth, large crabgrass, and yellow nutsedge; and for increasing marketable yields in low-density polyethylene (LDPE) –mulched bell pepper. Allyl ITC was applied at 450, 600, and 750 kg ha−1; metam sodium was applied at 180, 270, and 360 kg ha−1; and MeBr plus chloropicrin (67% and 33%, respectively) was applied at 390 kg ha−1. Allyl ITC and metam sodium did not injure bell pepper. Allyl ITC at 750 kg ha−1or metam sodium at 360 kg ha−1controlled Palmer amaranth (≥ 83%), large crabgrass (≥ 78%), and yellow nutsedge (≥ 80%) comparably to MeBr. Yellow nutsedge tuber density was ≤ 84 tubers m−2in plots treated with the highest rate of allyl ITC and metam sodium and was comparable to the tuber density in MeBr-treated plots. Although allyl ITC at 750 kg ha−1controlled weeds comparable to MeBr, total marketable bell pepper yield with allyl ITC was lower than the yield with MeBr. Conversely, total marketable bell pepper yield with the highest rate of metam sodium (53.5 ton ha−1) was equivalent to the yield (62.5 ton ha−1) in plots treated with MeBr. In conclusion, metam sodium at 360 kg ha−1is an effective MeBr alternative for weed control in LDPE–mulched bell pepper.


1997 ◽  
Vol 11 (3) ◽  
pp. 520-526 ◽  
Author(s):  
Theodore M. Webster ◽  
John W. Wilcut ◽  
Harold D. Coble

Experiments were conducted in 1991 and 1992 to evaluate the weed control effectiveness from several rates of AC 263,222 applied PPI and PRE (36 and 72 g ai/ha), early POST (EPOST) (18, 36, 54, or 72 g/ha), POST (18, 36, 54, or 72 g/ha), and EPOST followed by (fb) POST (27 fb 27 g/ha or 36 fb 36 g/ha). These treatments were compared to the commercial standard of bentazon at 0.28 kg ai/ha plus paraquat at 0.14 kg ai/ha EPOST fb bentazon at 0.56 kg/ha plus paraquat at 0.14 kg/ha plus 2,4-DB at 0.28 kg ae/ha. Application method had little effect on weed control with AC 263,222. In contrast, application rate affected control. Purple nutsedge, yellow nutsedge, prickly sida, smallflower morningglory, bristly starbur, common cocklebur, and coffee senna were controlled at least 82% with AC 263,222 at 36 g/ha (one-half the maximum registered use rate) regardless of application method. AC 263,222 at 72 g/ha (registered use rate) controlled sicklepod 84 to 93%, Florida beggarweed 65 to 100%, andIpomoeamorningglory species 89 to 99%. A single application of AC 263,222 at 36 g/ha or more controlled all weeds (with the exception of Florida beggarweed) as well or greater than sequential applications of bentazon plus paraquat fb bentazon, paraquat, and 2,4-DB. All rates of AC 263,222 applied POST and all application methods of AC 263,222 at 72 g/ha had better yields than the pendimethalin control.


2014 ◽  
Vol 24 (6) ◽  
pp. 663-667 ◽  
Author(s):  
Charles L. Webber ◽  
Merritt J. Taylor ◽  
James W. Shrefler

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%).


2014 ◽  
Vol 28 (2) ◽  
pp. 377-384 ◽  
Author(s):  
Pratap Devkota ◽  
Jason K. Norsworthy

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.


1996 ◽  
Vol 10 (4) ◽  
pp. 893-899 ◽  
Author(s):  
Nilda R. Burgos ◽  
Ronald E. Talbert

Studies were conducted at the Vegetable Substation in Kibler, AR, in 1992 and 1993, in the same plots, to evaluate weed suppression by spring-seeded cover crops and to determine the effects of cover crop and imazethapyr on no-till southern pea. A plot without cover, conventionally tilled before planting southern pea, served as control. Weed control treatments, applied as subplots in each cover crop, included a weedy check, handweeded check, and half and full rates of imazethapyr (0.035 and 0.07 kg/ha) followed by sethoxydim (0.22 kg/ha). Biomass of Palmer amaranth 6 WAR without herbicides, was less in Italian ryegrass and sorghum-sudangrass residues than in oat residue and no cover crop. Over the years, Palmer amaranth density increased 333% without cover crops and 28% with cover crops. Rice flatsedge density increased four to five times in oat and sorghum-sudangrass residues but remained the same in Italian ryegrass residue. In general, Italian ryegrass residue suppressed the most weeds. Oat residue was least suppressive. Italian ryegrass and sorghum-sudangrass also reduced southern pea stand. Regardless of cover crop and year, half and full rates of imazethapyr followed by sethoxydim equally reduced density of Palmer amaranth, goosegrass, large crabgrass, southwestern cupgrass, and rice flatsedge compared with the untreated check. Residual control of Palmer amaranth by imazethapyr was higher at the full rate than the reduced rate, regardless of cover crop. Half rate of imazethapyr followed by sethoxydim controlled 94 to 100% of Palmer amaranth, rice flatsedge, large crabgrass, and southwestern cupgrass late in the season, regardless of cover crop in 1992 and 1993. Southern pea yield in untilled plots with cover crops was two to three times lower than yield in plots with preplant tillage and no cover crops mostly because of reduction in crop stand in the presence of cover crops.


1999 ◽  
Vol 26 (1) ◽  
pp. 23-28 ◽  
Author(s):  
W. J. Grichar ◽  
P. A. Dotray ◽  
D. C. Sestak

Abstract Field experiments were conducted in 1995 through 1997 in south and west Texas to evaluate diclosulam [N-(2,6-dichlorophenyl)-5-ethoxy-7-fluoro(1,2,4)-triazolo(1,5c)-pyrimidine-2-sulfonamide] for weed control in peanut. Diclosulam applied preplant incorporated at 0.01 kg ai/ha in combination with ethalfluralin at 0.84 kg ai/ha controlled Texas panicum, Palmer amaranth, morningglory species, and golden crownbeard at least 95% and devil's-claw 91%. When diclosulam rates were increased to 0.02 kg/ha, yellow and purple nutsedge were controlled at least 89 and 72%, respectively. Diclosulam applied postemergence (POST) provided erratic yellow nutsedge control.


2017 ◽  
Vol 31 (5) ◽  
pp. 694-700 ◽  
Author(s):  
Peter M. Eure ◽  
A. Stanley Culpepper

Bell pepper producers are faced with the challenge of controlling weeds following the phase-out of methyl bromide (MBr). Numerous attempts have been made to find a single fumigant or herbicide to control a broad spectrum of weeds. Adequate weed control in bell pepper will likely require weed management systems utilizing both fumigant and herbicide options. A weed management system including the fumigant dimethyl disulfide (DMDS) plus chloropicrin (Pic) plus the herbicide napropamide prior to transplant followed byS-metolachlor POST may be necessary to replace MBr. Field experiments were conducted during 2010 and 2011 near Ty Ty, Georgia to determine bell pepper and weed response to DMDS plus Pic or in systems with napropamide and/orS-metolachlor. Bell pepper were not significantly injured by DMDS plus Pic or napropamide. Injury caused byS-metolachlor was transient and plants fully recovered by 4 weeks after treatment (WAT). Yellow nutsedge control 6 WAT using DMDS plus Pic applied at 468 or 560 L ha−1controlled yellow nutsedge 91 to 95%. Large crabgrass control 6 WAT was 92 to 100% when DMDS plus Pic was applied at 468 or 560 L ha−1with or without a(n) herbicide (S-metolachlor or napropamide). Palmer Amaranth control prior to harvest was 21, 64, and 85% using DMDS plus Pic at 374, 468, or 560 L ha−1, respectively. DMDS plus Pic applied at 468 or 560 L ha-1with napropamide followed byS-metolachlor POST gave 95 to 99% control of Palmer amaranth 6 WAT. Consistent weed control and optimum yields were obtained when DMDS plus Pic was used at 468 L ha−1plus napropamide beneath plastic mulch followed byS-metolachlor POST.


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
W. J. Grichar ◽  
P. A. Dotray

Field studies were conducted from 2007 through 2009 to determine weed efficacy and peanut (Arachis hypogaeaL.) response to herbicide systems that included ethalfluralin applied preplant incorporated. Control of devil's claw (Proboscidea louisianica(Mill.) Thellung), yellow nutsedge (Cyperus esculentusL.), Palmer amaranth (Amaranthus palmeriS. Wats.), and puncturevine (Tribulus terrestrisL.) was most consistent with ethalfluralin followed by either imazapic or imazethapyr applied postemergence. Peanut stunting was 19% when paraquat alone was applied early-postemergence. Stunting increased to greater than 30% when ethalfluralin applied preplant incorporated was followed byS-metolachlor applied preemergence and paraquat applied early-postemergence. Stunting (7%) was also observed when ethalfluralin was followed by flumioxazin plusS-metolachlor applied preemergence with lactofen applied mid-postemergence. Ethalfluralin followed by paraquat applied early-postemergence reduced peanut yield when compared to the nontreated check. Ethalfluralin applied preplant incorporated followed by imazapic applied mid-postemergence provided the greatest yield (6220 kg/ha). None of the herbicide treatments reduced peanut grade (sound mature kernels plus sound splits) when compared with the nontreated check.


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