Weed Technology最新文献

{"title":"Methiozolin rate and application frequency influence goosegrass and smooth crabgrass control in turf","authors":"John M. Peppers, J. Scott McElroy, Pawel M. Orlinski, James Baird, Pawel Petelewicz, Mikerly M. Joseph, I. Alejandra Sierra-Augustinus, Marco Schiavon, Shawn D. Askew","doi":"10.1017/wet.2024.5","DOIUrl":"https://doi.org/10.1017/wet.2024.5","url":null,"abstract":"Methiozolin is labeled for goosegrass and smooth crabgrass control in golf course putting greens, but no peer-reviewed literature exists regarding this use. Greenhouse experiments were conducted evaluating goosegrass and smooth crabgrass response to increasing rates of methiozolin as affected by weed growth stage. In general, as weed growth stage increased, the methiozolin rate required to reduce weed biomass 90% (WR<jats:sub>90</jats:sub>) increased. Goosegrass was more sensitive to preemergence-applied methiozolin than smooth crabgrass, and the WR<jats:sub>90</jats:sub> was 30.4 and 118 g ai ha<jats:sup>-1</jats:sup> for goosegrass and smooth crabgrass, respectively. However, smooth crabgrass was generally more sensitive to postemergence-applied methiozolin than goosegrass. Subsequent field studies were conducted to evaluate goosegrass and smooth crabgrass control with methiozolin applied singularly or sequentially at standard preemergence timings. Results indicated methiozolin applied singularly or sequentially at the label-recommended rate (500 g ha<jats:sup>-1</jats:sup>) is not persistent enough to provide season-long control of goosegrass and smooth crabgrass. Ten field studies were conducted in Alabama, California, Florida and Virginia to evaluate frequent methiozolin application programs with the objective of providing selective, season-long goosegrass and smooth crabgrass control. Results from these studies indicate methiozolin can be safely applied to hybrid bermudagrass and creeping bentgrass putting greens despite exceeding the yearly maximum use rate for putting greens (2500 g ha<jats:sup>-1</jats:sup>) with some treatments. Methiozolin effectively controlled smooth crabgrass throughout the growing season in California and Virginia when ten biweekly applications were applied at 250 g ha<jats:sup>-1</jats:sup> or higher. In Florida, methiozolin did not acceptably (80%) control goosegrass regardless of application rate. In Virginia, methiozolin acceptably controlled goosegrass only when applied at rates and frequencies that exceeded the maximum yearly methiozolin usage rate. These data indicate that methiozolin has the potential to control smooth crabgrass preemergence when applied frequently, but does not provide acceptable goosegrass control at labeled rates.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"35 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139766119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation-based nozzle density optimization for maximized efficacy of a machine-vision weed control system for applications in turfgrass settings","authors":"Paweł Petelewicz, Qiyu Zhou, Marco Schiavon, Gregory E. MacDonald, Arnold W. Schumann, Nathan S. Boyd","doi":"10.1017/wet.2024.7","DOIUrl":"https://doi.org/10.1017/wet.2024.7","url":null,"abstract":"Targeted spray application technologies have the capacity to drastically reduce herbicide inputs, but to be successful, the performance of both machine vision (MV) based weed detection and actuator efficiency need to be optimized. This study assessed 1) the performance of spotted spurge recognition in ‘Latitude 36’ bermudagrass turf canopy using the You Only Look Once (YOLOv3) real-time multi-object detection algorithm, and 2) the impact of various nozzle densities on model efficiency and projected herbicide reduction under simulated conditions. The YOLOv3 model was trained and validated with a dataset of 1,191 images. The simulation design consisted of 4 grid matrix regimes (3 × 3, 6 × 6, 12 × 12, and 24 × 24), which would then correspond to 3, 6, 12, and 24 non-overlapping nozzles, respectively, covering a 50-cm wide band. Simulated efficiency testing was conducted using 50 images containing predictions (labels) generated with the trained YOLO model and, by applying each of the grid matrixes to individual images. The model resulted in prediction accuracy of a <jats:italic>F</jats:italic>1 <jats:italic>Score</jats:italic> of 0.62 <jats:italic>precision</jats:italic> of 0.65 and <jats:italic>recall</jats:italic> value of 0.60. Increased nozzle density (from 3 to 12) improved actuator precision and predicted herbicide-use efficiency with a reduction in false hits ratio from <jats:sup>∼</jats:sup>30% to 5%. The area required to ensure herbicide deposition to all spotted spurge detected within images was reduced to 18% resulting in <jats:sup>∼</jats:sup>80% herbicide savings compared to broadcast application. Slightly greater precision was predicted with 24 nozzles, but not statistically different from the 12-nozzle scenario. Using this turf/weed model as a basis, optimal actuator efficacy and herbicide savings would occur by increasing nozzle density from one to 12 nozzles with the context of a single band.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"38 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139766219","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salvage Treatments for Barnyardgrass (Echinochloa crus-galli) Control in Rice Following Simulated Failed Herbicide Application","authors":"Hunter D. Bowman, Jason A. Bond, Thomas W. Allen, Daniel B. Reynolds, Taghi Bararpour, Darrin M. Dodds, Thomas W. Eubank","doi":"10.1017/wet.2024.3","DOIUrl":"https://doi.org/10.1017/wet.2024.3","url":null,"abstract":"Florpyrauxifen-benzyl was commercialized in 2018 to target barnyardgrass and aquatic or broadleaf weeds. Field studies were conducted from 2019 to 2021 in Stoneville, MS, to evaluate barnyardgrass control following a simulated failure of florpyrauxifen-benzyl or other common postemergence (POST) rice herbicides. In the first field study, florpyrauxifen-benzyl was applied at 0 and 15 g ai ha<jats:sup>-1</jats:sup> to rice at the two- to three-leaf stage to simulate a failed application targeting barnyardgrass. Sequential herbicide treatments included no herbicide and full rates of imazethapyr, quinclorac, bispyribac-Na, and cyhalofop applied 7 or 14 d after florpyrauxifen-benzyl treatment. The second field study was designed to evaluate barnyardgrass control with florpyrauxifen-benzyl following simulated failure of POST rice herbicides. Initial herbicide treatments included no herbicide and half rates of imazethapyr, quinclorac, bispyribac-Na, and propanil. Sequential applications at 7 or 14 d after the initial herbicide treatments included florpyrauxifen-benzyl at 0 and 30 g ai ha<jats:sup>-1</jats:sup>. Results from the first study indicated barnyardgrass control 21 d after final treatment (DAFT) was greater with sequential treatments at 7 compared with 14 d after initial treatment (DA-I) with no initial application of florpyrauxifen-benzyl. Therefore, delaying sequential treatments until 14 d after initial florpyrauxifen-benzyl at 15 g ha<jats:sup>-1</jats:sup> allowed barnyardgrass to become too large to control with other rice herbicides. Rough rice yield was reduced in plots where quinclorac application was delayed from 7 to 14 DA-I with no initial application of florpyrauxifen-benzyl. The second study suggested that florpyrauxifen-benzyl application should be delayed 14 d after a herbicide failure. While no differences in barnyardgrass control 21 DAFT were detected whether florpyrauxifen-benzyl was applied 7 or 14 DA-I of any herbicide utilized, &gt;85% control was only achieved when florpyrauxifen-benzyl application was delayed 14 DA-I. These results demonstrate barnyardgrass control options following simulated failed applications of common rice herbicides.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"37 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139657737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emergence Timing of Smallflower Umbrella Sedge (Cyperus difformis), Barnyardgrass (Echinochloa crus-galli), and Bearded Sprangletop (Leptochloa fusca spp. fascicularis) in California Water-Seeded Rice","authors":"Katie E. Driver, Aaron Becerra-Alvarez, Mohsen B. Mesgaran, Kassim Al-Khatib","doi":"10.1017/wet.2024.2","DOIUrl":"https://doi.org/10.1017/wet.2024.2","url":null,"abstract":"Late-season weed emergence in California rice fields complicates decisions concerning the timing of control measures. The objective of this study was to predict the emergence of three problematic weed species in rice using thermal time models. Smallflower umbrella sedge, barnyardgrass, and bearded sprangletop seedlings were counted and removed daily at three locations across the Sacramento Valley rice-growing region in 2018. The accumulation of thermal time (growing degree day, GDD) commenced with the initial flooding of the fields at each location, utilizing the specific base temperatures corresponding to each species. The pattern of emergence as a function of GDD was modeled with a Weibull function. Root-mean-square values for comparing actual and model-predicted cumulative emergence values were 6 to 23%. Cumulative percent emergence initially increased rapidly for smallflower umbrella sedge and reached 90% emergence with accumulation of 13 GDD. Barnyardgrass emerged after smallflower umbrella sedge and reached 90% emergence with an accumulation of 124 GDD. Bearded sprangletop had a delay of 64 GDD compared to barnyardgrass to reach first emergence and reached 90% emergence at 215 GDD. The period of weed emergence at all field sites differed across the three species and led to a continuous spectrum of weed emergence over time. This study characterized the emergence of three economically important rice weeds and provided useful information for the timing of weed management. Typical herbicide applications on the day of seeding may have less efficacy on the late-emerging weeds, causing reduced weed control. Delaying herbicide applications, overlay of residual herbicides, or use of herbicides with longer residual activity are suggested to control late-emerging weeds.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"5 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139581210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Weed communities after decades of mineral fertilization and tillage treatments in a corn-soybean rotation","authors":"Marie-Josée Simard, Noura Ziadi","doi":"10.1017/wet.2024.1","DOIUrl":"https://doi.org/10.1017/wet.2024.1","url":null,"abstract":"Soil fertility and disturbance can potentially modify weed dynamics in a corn-soybean rotation. Knowing how added mineral fertilizers and tillage influence weed populations in the long term can provide insight into weed community shifts, which may affect future weed management requirements. The first objective of this study was to evaluate the effect of 24-25 years of nitrogen and phosphorus fertilization treatments, and tillage (moldboard vs. no tillage) on weeds (density, biomass and composition) before and after herbicide applications in 2016/corn and 2017/soybean. The second objective was to evaluate the effect of the same treatments six years after no post-emergence weed management in 2022/corn. Since the last evaluation performed in 2004, weed density, richness, and diversity increased, and more annual grasses were observed under both tillage regimes. No fertilization effect was observed on any weed variables, including composition, except for increased biomass when left to grow all season after crop planting. In managed plots, the density and biomass of annuals and perennials was generally higher in no-till, and discrepancies were highest for annual grass densities before herbicide application. Weed species richness and diversity based on counts were equivalent between tillage regimes, but total biomass was distributed between more species in no-till. Higher weed densities and concurrent weed biomass, observed in no-till, reduced crop yields in 2016/soybean only. The combination of low crop diversity and low use of residual herbicides during the trial potentially led to the observed species shifts and increased weed density.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"3 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139590445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of herbicide programs for the control of knotroot foxtail [Setaria parviflora (Poir.) Kerguélen] in bermudagrass pasture","authors":"Logan M. Dyer, Gerald M. Henry, Patrick E. McCullough, Jason Belcher, Nicholas T. Basinger","doi":"10.1017/wet.2023.98","DOIUrl":"https://doi.org/10.1017/wet.2023.98","url":null,"abstract":"Knotroot foxtail has become more prevalent and problematic in pastures and hayfields in the southeastern United States. There are currently gaps in herbicide programs for the management of this species in bermudagrass forage production. This study was conducted to determine the efficacy of programmatic approaches to control knotroot foxtail in bermudagrass with fall postemergence (POST) herbicide applications, with and without spring preemergence (PRE) herbicide applications. The study was a randomized complete block with a factorial arrangement of treatments and included a non-treated control for both fall and spring timings. Glyphosate at two rates (0.35 or 0.7 kg ae ha<jats:sup>-1</jats:sup>), nicosulfuron (0.07 kg ai ha<jats:sup>-1</jats:sup>) + metsulfuron (0.012 kg ai ha<jats:sup>-1</jats:sup>), and hexazinone (1.3 kg ai ha<jats:sup>-1</jats:sup>) were applied alone in the fall or followed by indaziflam (0.067 kg ai ha<jats:sup>-1</jats:sup>) or pendimethalin (4.46 kg ai ha<jats:sup>-1</jats:sup>) in the spring. Three harvests were conducted throughout the growing season to evaluate weed species (knotroot foxtail, large crabgrass, and horsenettle) and bermudagrass biomass as well as overall species composition. The combination of fall and spring treatments did not affect weed species or bermudagrass biomass. Therefore, treatment main effects were analyzed by fall or spring application timing. A spring application of either pendimethalin or indaziflam increased bermudagrass biomass when compared to the non-treated control. However, neither PRE herbicide effectively reduced knotroot foxtail biomass when compared to the non-treated control. Although, pendimethalin did reduce season-long knotroot foxtail composition. Spring PRE herbicides are an effective tool for forage producers, but further research is needed to identify effective herbicides and additional approaches for the control of knotroot foxtail.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"24 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462685","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of carrier water pH and hardness on imazapic efficacy for sicklepod (Senna obtusifolia L.) control in peanut","authors":"Olumide S. Daramola, Gregory E. MacDonald, Ramdas G. Kanissery, Barry L. Tillman, Hardeep Singh, Pratap Devkota","doi":"10.1017/wet.2023.96","DOIUrl":"https://doi.org/10.1017/wet.2023.96","url":null,"abstract":"Carrier water quality is an important consideration for herbicide efficacy. Field and greenhouse studies were conducted from 2021 to 2023 to evaluate the effect of carrier water pH and hardness on imazapic efficacy for sicklepod control in peanut. Imazapic was applied postemergence at 0.071 kg a.i ha<jats:sup>-1</jats:sup> with carrier water pH levels (5, 6, 7, 8 or 9); and hardness levels: 0 (deionized water), 100, 200, 400 or 500 mg L<jats:sup>−1</jats:sup> of CaCO<jats:sub>3</jats:sub> equivalent in separate field experiments. In greenhouse experiments, imazapic was applied to either 10-cm, 15-cm, or 20-cm-tall sicklepod at similar carrier water pH levels and hardness 0, 100, 200, 400, or 800 mg L<jats:sup>−1</jats:sup> of CaCO<jats:sub>3</jats:sub>. In the field study, sicklepod control, density and biomass reductions were lower with carrier water pH 5 or 9 compared with pH 7. In the greenhouse study, control was not different among carrier water pH levels when imazapic was applied to 10-cm sicklepod; however, when applied to 15-cm or 20-cm sicklepod, control was at least 25% greater with acidic (pH 5) compared with alkaline (pH 9) carrier water. Results from the field study showed that carrier water hardness ≤500 ppm did not reduce imazapic efficacy for sicklepod control. In the greenhouse study, regardless of sicklepod height, carrier water hardness 800 mg L<jats:sup>-1</jats:sup> reduced sicklepod control by 15% and biomass reduction by 17% compared with deionized water (pH 7). The effects of carrier water pH and hardness on imazapic efficacy did not compromise peanut yield in the field study. However, this study indicates both acidic and alkaline carrier water pH and hardness (800 mg L<jats:sup>-1</jats:sup> CaCO<jats:sub>3</jats:sub> L<jats:sup>-1</jats:sup>) has the potential to reduce imazapic efficacy on sicklepod, and appropriate spray solution amendments maybe be needed to maintain optimum efficacy.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"17 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139462461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphorus influence on the critical period of weed control in sweet corn","authors":"Alex G. Rodriguez, Hardev S. Sandhu, Alan L. Wright, D. Calvin Odero","doi":"10.1017/wet.2023.95","DOIUrl":"https://doi.org/10.1017/wet.2023.95","url":null,"abstract":"Understanding the effect of phosphorus (P) fertilization on weed interference with sweet corn is important for deciding appropriate fertilization levels and weed control programs. Field experiments were conducted in 2020 and 2021 in Belle Glade, FL to determine the influence of P fertilization levels (0 or residual P, 62.5, and 120 kg P<jats:sub>2</jats:sub>O<jats:sub>5</jats:sub> ha<jats:sup>-1</jats:sup>) on the critical period of weed control (CPWC) in sweet corn on organic soils. Experimental plots were subjected to increased duration of weed interference and weed-free period treatments for each P fertilization level. The beginning and end of the CPWC based on 5% and 10% acceptable yield loss levels were determined by fitting log-logistic and Gompertz models to represent the increasing duration of weed interference and duration of the weed-free period, respectively. The log-logistic curves did not estimate the beginning of the CPWC at 5% AYL for 0 and 125 kg P<jats:sub>2</jats:sub>O<jats:sub>5</jats:sub> ha<jats:sup>-1</jats:sup> because the estimated upper limits of the curves were lower than the 95% relative yield used for estimation of 5% AYL. Based on 10% AYL level, the length of the CPWC in sweet corn under optimum P fertilization level was estimated to be 27 days, from the six- to seven-leaf stage until the silking stage of growth. Reducing P fertilization by 50% increased the CPWC to 36 days, from the five-leaf stage until the silking to blister stage of growth. Lack of P fertilization increased the CPWC to 64 days, from sweet corn emergence until the blister to milk stage of growth. These results show that the beginning of CPWC in sweet corn is delayed and the end shortened as P fertilization level increases. Therefore, reduction in P fertilization will require a more intensive weed management program for sweet corn because of the prolonged duration of the CPWC.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139052088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Postemergence-directed applications of pendimethalin for control of early-season weeds in chile pepper","authors":"Akash Bajagain, E. Lehnhoff, Robert Steiner, Rebecca Creamer, Brian J. Schutte","doi":"10.1017/wet.2023.91","DOIUrl":"https://doi.org/10.1017/wet.2023.91","url":null,"abstract":"\u0000 In New Mexico chile pepper production, pendimethalin is traditionally applied shortly after crop thinning, which is 9 to 10 wk after crop seeding. Pendimethalin applications before crop thinning may be a method for controlling early-season weeds in chile pepper; however, chile pepper tolerance to early-season applications of pendimethalin is poorly understood. We conducted a greenhouse study to evaluate young chile pepper responses to pendimethalin. We also conducted a field study to determine weed and chile pepper responses to early-season, postemergence-directed (POST-directed) pendimethalin in combination with herbicides registered for preemergence (PRE) applications. The greenhouse study included three treatments administered when chile pepper was at the 4-leaf stage: 1) pendimethalin applied to foliage and soil, 2) pendimethalin applied soil only, and 3) a non-treated control. The field study included four treatments: 1) PRE applications of napropamide followed by POST-directed pendimethalin at 5 wk after crop seeding, 2) PRE applications of clomazone followed by POST-directed pendimethalin at 5 wk after crop seeding, 3) POST-directed pendimethalin without PRE herbicides, and 4) non-treated, weed-free control. We conducted the field study at two sites that differed in soil texture. Pendimethalin application rates were maximum labelled rates for the specific soil. Results from the greenhouse study indicated that pendimethalin applied to foliage and soil stunted two of five cultivars, whereas pendimethalin applied to soil did not affect chile pepper height, fresh weight, dry weight, and root area. Results from the field study indicated POST-directed pendimethalin did not affect chile pepper height or fruit yield, or cause visual symptoms of herbicide injury. POST-directed pendimethalin reduced the densities of weeds, including junglerice. The results of this study indicate that POST-directed applications of pendimethalin at 5 wk after crop seeding do not cause crop injury or yield loss, while providing some weed control benefits, in chile pepper.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"26 13","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138947214","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palmer amaranth (Amaranthus palmeri) control affected by weed size and herbicide spray solution with nozzle type pairings","authors":"K. B. Kouamé, Thomas R. Butts, J. Norsworthy, Jason Davis, L. B. Piveta","doi":"10.1017/wet.2023.92","DOIUrl":"https://doi.org/10.1017/wet.2023.92","url":null,"abstract":"\u0000 Palmer amaranth can grow 4.2 mm in height per degree day; hence, delays of a few days in weed control deployment can result in applications to larger than labeled weeds. Therefore, it is critical to understand the impact of plant size at the time of application in conjunction with herbicide spray solution and nozzle type pairings on the effectiveness of weed management programs in the Enlist E3 and XtendFlex production systems. Field experiments were conducted in 2020, in no-crop conditions, at the Milo J. Shult Agricultural Research & Extension Center in Fayetteville, AR, and the Jackson County Extension Center near Newport, AR, to evaluate the influence of Palmer amaranth size on its control with glufosinate, dicamba, and 2,4-D applied alone and in mixture with specific nozzle pairings as mandated by label requirements. Also, a laboratory experiment was conducted at the Lonoke Extension Center (Lonoke, AR) to evaluate the droplet size and velocity of the spray solutions and nozzles used for the field experiment. A 5- and 10-percentage point reduction in control was observed when applying dicamba (66%) and 2,4-D (63%) alone, respectively compared to each mixed with glufosinate (71% and 73%, respectively). Palmer amaranth density increased to 55, 73, 100, 115, and 140 plants m-2 when 15-, 25-, 41-, 61-, and 76-cm tall plants were sprayed, respectively, compared to when 5-cm tall plants were sprayed (9 plants m-2). Nozzle types did not impact weed control and density. The addition of glufosinate to 2,4-D increased the percentage of driftable fines compared to 2,4-D alone. Effective short- and long-term chemical control of Palmer amaranth will require growers to be timely with their weed management programs, overlay residuals, and expect the need for sequential applications.","PeriodicalId":23710,"journal":{"name":"Weed Technology","volume":"56 11","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138946242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}