Broadleaf Herbicides Research Articles

Chemical weed management in wheat (Triticum aestivum) using ready-mix and tank-mix herbicides

A field experiment was conducted at the Bichpuri, Agra, Uttar Pradesh during the winter (rabi) seasons of 2011–12 and 2012–13, to evaluate the effect of different grass and broad-leaf herbicides as sole and ready-mix application on weed control in wheat (Triticum aestivum L.). Ready-mix application of herbicides proved better than their alone application in suppressing weed number and dry weight. Application of sulfosulfuron + metsulfuron (25 + 4 g/ha) resulted in the highest weed-control efficiency (WCE) as well as herbicide efficiency (HEI) and lowest weed index of 94.8%, 2.97 and 3.3 respectively. The highest grain and stover yield of 4.05 and 6.39 t/ha were obtained from weed-free treatment, although this remained statistically at par with sulfosulfuron + metsulfuron (25 + 4 g/ha) and both the treatments resulted in an increase of 34.6 and 30.2% in grain yield as compared to weedy check respectively. The highest net returns ( 43,200/ha) and benefit: cost ratio (2.40) were obtained with ready-mix application sulfosulfuron metsulfuron (25 + 4 g/ha) among the tested herbicide treatments.

Control of Echinochloa spp. and Leptochloa fascicularis with the novel dihydroorotate dehydrogenase inhibitor herbicide tetflupyrolimet in California water-seeded rice

Abstract The spread of herbicide-resistant weeds is considered a major problem for rice production in California, and there is a need for new herbicides. Tetflupyrolimet is a new herbicide with a novel dihydroorotate dehydrogenase–inhibiting site of action that has strong activity on grasses. Three field studies were conducted at the California Rice Experiment Station in Biggs, CA, in 2022 and 2023 to (1) determine control of watergrass species and bearded sprangletop with tetflupyrolimet, (2) characterize the effects of tetflupyrolimet combined with other herbicides on weed control and rice, and (3) determine the response of rice cultivars to tetflupyrolimet. In the first study, tetflupyrolimet was applied at preemergence (PRE) or at the 1- to 2-leaf stage of rice (POST) at 0.1, 0.125, or 0.15 kg ai ha−1 followed by carfentrazone. Tetflupyrolimet provided ≥99% control of watergrass species and 100% bearded sprangletop control regardless of the rate or application timing, while showing no crop injury symptoms or yield reduction. In the second study, tetflupyrolimet was applied PRE or POST at 0.1 or 0.15 kg ai ha−1 followed by herbicides labeled for use in California rice production. Tetflupyrolimet provided ≥98% control of watergrass species, which was better than the grower standard treatment, and ≥97% control of bearded sprangletop. In the third study, tetflupyrolimet was applied PRE or POST at 0.125, 0.15, 0.25, or 0.3 kg ai ha−1 followed by carfentrazone. The six California rice cultivars evaluated, ‘M-105’, ‘M-206’, ‘M-209’, ‘M-211’, ‘L-208’, and ‘CM-203’, did not show any trend of crop injury caused by tetflupyrolimet. Overall, tetflupyrolimet provided a high level of control of watergrass species and bearded sprangletop without causing visual rice injury or yield reductions, regardless of rice cultivar, when applied alone or in combination with commonly used sedge and broadleaf herbicides in California water-seeded rice.

Control of multiple-herbicide-resistant waterhemp with acetochlor-based herbicide mixtures in soybean

Abstract Waterhemp has evolved resistance to Group 2, 5, 9, 14, and 27 herbicides in Ontario, Canada, making control of this challenging weed even more difficult. Acetochlor is a Group 15, chloroacetanilide herbicide that has activity on many small-seeded annual grasses and some small-seeded annual broadleaf weeds, including waterhemp. The objective of this study was to ascertain if acetochlor mixtures with broadleaf herbicides (dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin), applied preemergence (PRE), increase multiple-herbicide-resistant (MHR) waterhemp control in soybean. Five trials were conducted over 2 yr (2021 and 2022). The acetochlor mixtures caused ≤7% soybean injury, except acetochlor + flumioxazin, which caused 19% soybean injury. Acetochlor applied PRE controlled MHR waterhemp 89% at 4 wk after application (WAA). Dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin controlled MHR waterhemp 59%, 67%, 58%, 64%, and 86%, respectively, at 4 WAA. Acetochlor applied in a mixture with dicamba, metribuzin, diflufenican, sulfentrazone, or flumioxazin provided good to excellent control of MHR waterhemp; control ranged from 91% to 98% but was similar to acetochlor applied alone. Acetochlor alone reduced MHR waterhemp density and biomass 98% and 93%; acetochlor + flumioxazin reduced waterhemp density and biomass by an additional 2% and 7%, respectively. This research concludes that acetochlor applied in a mixture with flumioxazin was the most efficacious mixture evaluated for MHR waterhemp control.

Synthetic auxin herbicides do not injure intermediate wheatgrass or affect grain yield

AbstractIntermediate wheatgrass (IWG) is a cool-season perennial grass developed as a dual-purpose grain and forage crop. One barrier to adopting this crop is a lack of information on the effects of herbicides on IWG for grain production. An experiment was conducted to evaluate herbicide effects on IWG grain yield, crop injury, and weed control over 2 yr (2019 to 2021) at sites in Wisconsin, Minnesota, New York, and North Dakota. This evaluation included broadleaf herbicides registered for use on wheat: 2,4-D amine, clopyralid, MCPA, and a mixture of clopyralid + MCPA (all are categorized as Group 4 herbicides by the Weed Science Society of America). Each herbicide or mixture was applied at 1× and 2× the labeled wheat application rate to newly planted and established (1- to 5-yr-old) IWG stands in the fall or spring. Herbicides were applied during IWG tillering or jointing stages in the fall or during the jointing stage in the spring. Across site years, application timing, herbicide, and application rate showed no effect on IWG grain yield or plant injury. Broadleaf weed control ranged from 71% to 92% across herbicide treatments relative to the nontreated check at the Wisconsin site, whereas weed control at the Minnesota site was variable among treatments. At the New York site, herbicides were equally effective for broadleaf weed suppression, whereas weed pressure was very low at the North Dakota site and treatments did not affect weed cover. The results show that newly planted and established stands of IWG are tolerant to the synthetic auxin herbicides 2,4-D amine, clopyralid, and MCPA when applied during tillering or jointing in the fall or during jointing in the spring. Synthetic auxins represent a potentially useful tool for weed control in IWG cropping systems, especially for problematic broadleaf weed species.

Reducing herbicide input and optimizing spray method can minimize nontarget impacts on native grassland plant species.

Invasive plants threaten biodiversity worldwide and effective management must control the target invader while conserving biodiversity. Herbicide is often used to control invasive plants, but potential negative impacts on biodiversity have led to spot spraying being recommended over boom spraying to minimize the exposure of nontarget species to chemicals. We examined the influence of herbicide application methods on off-target plant communities in threatened temperate grasslands of southeastern Australia, where spraying with the broadleaf herbicide fluroxypr is commonly used to control St. John's wort, Hypericum perforatum L. It is well established that fluroxypr effectively controls H. perforatum but few studies have examined its impact on native forbs. A spray drift experiment using water-sensitive cards indicated that ground surface coverage was higher for spot spraying (91%-99%) than for boom spraying (5%-31%). We established a replicated, 3-year, before-after-control-impact experiment across 48 1-m2 quadrats to determine how three herbicide application methods (spot spray, fine boom and coarse boom) affected nontarget native forbs, the group most likely to be affected by broadleaf herbicides. This experiment was conducted in grasslands where H. perforatum was almost absent, so responses would reflect the direct impacts of the chemical, rather than structural changes resulting from removal of the target invader. Spot spraying decreased the probability of occurrence of native leguminous forbs, while increasing the occurrence of exotic leguminous forbs and the richness of all exotic species and exotic annual forbs. Spot spraying reduced the occurrence of the native Desmodium varians and the abundance of the native Chrysocephalum apiculatum. During this 3-year study, native species appeared to be impacted either directly by fluroxypr or indirectly by increased competition with exotic species. Where herbicide application is deemed crucial in these grasslands, we recommend boom spraying when H. perforatum density is moderate to high. Spot spraying should only be used when the density of H. perforatum is very low. Given the regional variation in H. perforatum density, the spatial scale of invasion, soil depth, and conservation values, we present a decision tree to assist managers in evaluating the costs and benefits of chemical control, indicating situations where alternative or modified methods could be used.

Use of multivariate analysis and machine learning methods to characterize traits contributing to wheat yield diversity

Aim of study: Regarding the third largest staple food crop in the world, determining the factors affecting wheat yield is of great importance. This study aimed to determine useful subsets of agronomic traits and evaluate the order of importance of traits in grain yield. Area of study: Fars province, Iran. Material and methods: In total, the data corresponding to 22 agronomic traits was collected from six different regions (Darab, Kavar, Marvdasht, Fasa, Lar, and Khonj) of 90 farms of Fars province, Iran as the most important wheat-growing regions. Multivariate statistical analysis (correlation, stepwise regression, and principal component analysis (PCA)) and machine learning modeling approaches, such as partial least squares regression (PLSR) and support vector regression (SVR) models, were applied to agronomic traits. Main results: The findings, based on integrated approaches such as correlation, stepwise regression, and PCA, highlighted that number of spikes m-2, grain number spike-1, and thousand-grain weight had a major impact on the yield followed by awn length, spike length, narrow leaf herbicide, broadleaf herbicide, time to plant maturity (month), and soil salinity. Besides, PLSR with nine inputs (nine selected traits) displayed better prediction capability (R2=85 %, RMSE=0.32, MSE=0.10, and BIAS=-0.05) than that with all twenty-two input traits. Research highlights: Integrated multivariate statistical analyses and machine learning regression methods could be a powerful tool in determining traits that have a significant impact on yield. These achievements can be considered for future breeding programs.

Establishment of Tall Fescue Seeded after Postemergence Broadleaf Herbicide Application

Successful weed control before seeding is necessary for proper turfgrass establishment. However, herbicide labels differ in the time required between application and seeding. The objective of this research was to determine the influence of four postemergence broadleaf combination herbicides on tall fescue (Festuca arundinacea) cover, normalized difference vegetation index (NDVI), and canopy height when seeded 0, 3, 7, and 14 days after herbicide application. Herbicide treatments included the following: 1) a nontreated control; 2) 0.03 lb/acre carfentrazone-ethyl + 0.09 lb/acre methylchlorophenoxypropionic acid (MCPP) + 1.44 lb/acre 2,4-dichlorophenoxyacetic acid (2,4-D) + 0.30 lb/acre dicamba; 3) 0.20 lb/acre fluroxypyr + 0.01 lb/acre halauxifen-methyl + 1.44 lb/acre 2,4-D choline; 4) 0.20 lb/acre triclopyr + 0.003 lb/acre pyraflufen-ethyl + 1.72 lb/acre 2,4-D + 0.14/acre dicamba; and 5) 0.04 lb/acre penoxsulam + 0.04 lb/acre sulfentrazone + 0.40 lb/acre 2,4-D + 0.11 lb/acre dicamba. Penoxsulam + sulfentrazone + 2,4-D + dicamba reduced tall fescue cover, NDVI, and canopy height compared with the nontreated. This research demonstrates seeding between 0 to 14 days after an application of carfentrazone-ethyl + MCPP + 2,4-D + dicamba, fluroxypyr + halauxifen-methyl + 2,4-D choline, or triclopyr + pyraflufen-ethyl + 2,4-D + dicamba will result in successful tall fescue establishment under the conditions evaluated in these experiments.

Aplicações de herbicidas em pré e/ou pós-emergência da soja podem afetar a qualidade de sementes?

ABSTRACT Soybean cultivation requires herbicide application in the off-season, before emergence for weed desiccation, and after emergence. It is believed that the use of preand post-emergent herbicides combined with preharvest application may negatively affect the quality of soybean seeds. As such, the present study aimed to assess the effect of preand post-emergent herbicides on soybean seed quality. Five field experiments were conducted during the 2018/2019 and 2019/2020 growing seasons to investigate the effects of synthetic auxins and pre-emergents, acetyl-CoA carboxylase (ACCase) inhibitors, broadleaf herbicides, and s-metolachlor or clomazone on the quality of soybean seeds. Dicamba application combined with the pre-emergent herbicides imazethapyr/flumioxazin before soybean planting reduced seed vigor and germination. ACCase inhibitors in association with broadleaf herbicides before planting had no effect on seed quality. Applying s-metolachlor (up to 2,880 g of active ingredient [ai] ha-1) or clomazone (up to 1,800 g ai ha-1) was safe for seed germination, even when used after soybean emergence.

Epigaeic spider response to sagebrush steppe restoration treatments

Epigaeic (ground-active) spiders are dominant predators of arthropods and are important prey for vertebrates in sagebrush steppe systems. As part of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP), the response of epigaeic spiders to sagebrush steppe restoration treatments was evaluated. Spiders were pitfall trapped pre-treatment and for up to 7 years post-treatment at 20 sites in the interior western United States. Spider species, functional groups, and communities were analyzed as regards site conditions and in response to treatments (prescribed fire, mechanical, and herbicide) designed to restore sagebrush steppe lands encroached by piñon–juniper woodlands (Pinus and Juniperus spp.) and invaded by cheatgrass (Bromus tectorum). A total of 10,149 epigaeic spiders were caught during the 8-year sampling period (2006–2014), comprising 18 families, 51 genera, and 109 species. Ten species are currently undescribed, including two species of jumping spiders (Salticidae), two species of funnel spiders (Agelenidae), and a species of trapdoor spider (Euctenizidae). Nearly 70% of adult catch comprised the 10 most commonly collected species; 50 species were caught fewer than five times. Spiders of the family Gnaphosidae (ground spiders) dominated the collection (65% of adults), followed by wolf spiders (Lycosidae; 12%), jumping spiders (8%), and crab spiders (Thomisidae; 4%). Fewer gnaphosids were caught in plots with higher tree cover, and this pattern was reversed by tree removal. There was no significant epigaeic spider response to the broadleaf herbicide tebuthiuron, nor to mowing or clear-cutting. Mastication caused a subtle increase in epigaeic spider richness at Utah juniper sites. Prescribed fire decreased abundance and richness of epigaeic spiders in the short term (1 year post-treatment), with catch at most sites converging to control levels by Year 2 post-treatment; application of the annual herbicide imazapic at treeless sites may have amplified this effect slightly in the short term. In general, gnaphosid catch and richness closely paralleled litter and bunchgrass cover. These patterns suggest that while gnaphosid spiders are not sagebrush-obligate species per se, these spiders prefer habitat conditions that provide more hiding cover, in the form of litter and vegetation, found more often in treeless sagebrush steppe plant communities and in woodland communities that have relatively lower tree cover.

Intra‐site sources of restoration variability in severely invaded rangeland: Strong temporal effects of herbicide–weather interactions; weak spatial effects of plant community patch type and litter

Abstract Invasions by exotic annual grasses (EAGs) are replacing native perennials in semiarid areas globally, including the vast sagebrush‐steppe rangelands of western North America. Efforts to eradicate EAGs and restore perennials have had mixed success, especially in relatively warm and dry areas where EAGs had high dominance prior to intervention. Greater consideration of the ecological sources of variability in EAG treatment outcomes may improve success. We hypothesized that herbicide and restoration outcomes would be influenced by restoration strategy (type of herbicide, seeding or planting, timing of treatment) and underlying spatial variability associated with plant community patch type and litter, all applied in a landscape‐scale experiment in a severely invaded area in Southern Idaho, USA. EAGs, specifically medusahead (Taeniatherum caput‐medusae [L.] Nevski), were strongly reduced for up to 3 years (maximum observation period) by the pre‐emergent herbicide indaziflam, whereas the pre/post‐emergent imazapic reduced EAGs only when applied twice. Indaziflam effects were greater when post‐spray moisture was greater, and also when co‐applied with imazapic, but reapplying indaziflam did not lead to additional reduction of EAGs. Imazapic and indaziflam each stimulated species‐specific, secondary invasion by exotic and/or invasive tall forbs. Application of the broadleaf herbicide aminopyralid provided only a fleeting 1 year of control of a dominant, highly noxious forb skeletonweed (Chondrilla juncea L.). Underlying heterogeneity in plant community patch type (dominant herb species) explained only ∼5% of variation in the herbicide effects, and manipulation of litter prior to spraying had no effect. Several years of seedings and planting resulted in no establishment of native perennials. Herbicides, especially indaziflam, appear to be an effective tool for reducing EAGs for multiple years in the challenging restoration conditions we evaluated, particularly if their application coincides with suitable moisture. However, restoring the perennials required for longer term resistance to reinvasion is a serious challenge that could be avoided with preservation of perennials.

Determination of Efficacy of Broad Leaf Herbicides on Various Weed Floras in Wheat Field under Rain Fed Production System

Determination of Efficacy of Broad Leaf Herbicides on Various Weed Floras in Wheat Field under Rain Fed Production System

FirstAct for Efficacy in ACCase-Tolerant Grain Sorghum

The objective of this study was to compare FirstAct with several tank mix partners for efficacy in herbicide-tolerant grain sorghum. FirstAct (quizalofop) alone or in tank mixtures controlled Johnsongrass 94% or more. However, tank mixing FirstAct with any broadleaf herbicide was generally antagonistic to Palmer amaranth control. Minor sorghum injury was 5% or less by four weeks after postemergence treatment. Sorghum yields increased with all postemergence treatments except with atrazine alone.

WILD BITTER GOURD, MOMORDICA CHARANTIA L. (CUCURBITACEAE): A CREEPING WEED OF OIL PALM AND ITS MANAGEMENT

This paper reviews information on the biological aspects and discusses briefly the weediness of wild bitter gourd (WBG) including its management, in oil palm plantations. WBG is considered a serious weed in oil palm plantations because: i) it can grow into blanket sheet in the inter-row areas in immature and mature plantings, ii) it can encroach onto immature palms which is difficult to control and increase risks of herbicide phytotoxicity during routine circle spraying, and iii) it can grow as epiphytes on palm trunks requiring control (both as a weed and also sources of seeds for further infestation). The control of WBG in oil palm plantations involves various measures which include preventive measures (planting legume covers, maintenance of natural covers, mulching) and applied measures (manual and mechanised weeding, chemical control). The planting of legume covers and the maintenance of a less competitive natural cover of selected indigenous species in oil palm plantations are sound methods of weed management including the exclusion of noxious weeds (like WBG). When WBG encroaches onto immature palms, manual weeding or decreeping is the only safe method of weed control. Post emergent chemical control of M. charantia has been reported by many researchers and they make no recommendations for the efficacy or suitability of these herbicides against M. charantia in named crops. A WBG herbicide evaluation with six herbicide treatments gave effective control after three rounds of spraying. These are: (i) paraquat + metsulfuron methyl at 2.8 L + 75 g per hectare, (ii) glyphosate + metsulfuron-methyl at 1.5 L + 75 g per hectare, (iii) glufosinate-ammonium at 3 L per hectare, (iv) fluroxypyr at 2 L per hectare, (v) dicamba at 1.5 L per hectare and (vi) triclopyr at 1.5 L per hectare. In any spraying programme to eradicate thick sheet growth of WBG in inter-row areas, three rounds of spraying were required to achieve complete eradication by killing off the original weed stand and killing off any regeneration/new seedlings from germination of seeds. However, the risks of crop phytotoxicity limits the choice of herbicide to only spraying of paraquat + metsulfuron-methyl at 2.8 L + 75 g per hectare and glufosinate-ammonium 3 L per hectare for the control of WBG and other weeds around the periphery of the immature palm during circle spraying. More important, careful spraying by trained operators to minimise lower frond contact is required. Paraquat is not available now and may be replaced with sodium chlorate (sodium chlorate + metsulfuron-methyl at 5.5 kg + 75 g per ha). Another approach can be the sequential spraying of the herbicide mixtures: two rounds of spraying glyphosate + metsulfuron-methyl and the third spraying with only a single selective broadleaf herbicide (fluroxypyr, or dicamba, or triclopyr) to kill any WBG regeneration in order to allow the growing of soft grasses as natural covers. Keywords: Momordica charantia, wild bitter gourd, weed, oil palm plantations, management

The Joint Action of Some Broadleaf Herbicides on Potato (Solanum tuberosum L.) Weeds and Photosynthetic Performance of Potato

Herbicide mixtures are a modern weed management practice as they reduce herbicide application. This study aimes to evaluate the effect of metribuzin, halosulfuron and flumioxazin applied individually and as mixtures (metribuzin:halosulfuron and metribuzin:flumioxazin) on Chenopodium album, Amaranthus retroflexus, and potatoes on biomass and chlorophyll-a fluorescence in 21 experiments. The individual herbicide experimental design was a randomized completely block design with seven doses and three replications. The factorial experiments were performed on the basis of randomized completely block design in three replications for binary mixture experiments. Flumioxazin was very potent in controlling C. album, A. retroflexus, and injured potatoes with a 50% effective dose (ED50) of 1.21, 0.54, and 12.23 g ai·ha−1, respectively. Both mixtures of metribuzin:halosulfuron and metribuzin:flumioxazin generally showed an antagonistic effect on both weeds and potato in 12 independent experiments. Metribuzin, halosulfuron, and flumioxazin significantly decreased photosystem II activity by decreasing the maximum quantum efficiency (Fv/Fm). The metribuzin:halosulfuron mixtures almost followed the Additive Dose Model for Fv/Fm, whilst there was an antagonistic effect for the metribuzin:flumioxazin that was closely related to biomass. The results indicated that mixtures were generally antagonistic, and the endpoint choice is pivotal when assessing the joint action of mixtures.

Analysis of Weed Growth in Rabi Crop Agriculture Using Deep Convolutional Neural Networks

Weed interference for the duration of crop establishment is a severe difficulty for wheat in North India [22.9734 ° N, 78.6569 ° E]. In situ far-flung detection for precision herbicide application minimizes the danger of both crop damage and herbicide input. This research paper focuses on the comparative study of crop growth and its effect at three different places in Madhya Pradesh [24.5840° N, 81.5020° E] India[20.5937° N, 78.9629° E]. These weed species included Pigweed (Amaranthaceae ), Goosefoot [Chenopodiaceae], Wild oat species (Poaceae), livid amaranth (Amaranthus blitum L.), Fathen[Chenopodiaceae (L.) Wild.], and Bermuda grass (Poaceae L.) a significant weed for rabi crop production in India with sensitivity to clopyralid, is the best available put up broadleaf herbicide. The intention of the Takes a look to assess the accuracy of four different CNNs architectures to locate the weed images of the Rabi crop of the family of various Rabi crops growing in competition with Rabi crops at 3 sites in Madhya Pradesh. Four CNNs have been compared, including object detection-primarily based ResNet-50, image classification-based VGGNet-16, Inception v4 and EfficientNet-B7 the EfficientNet-B7 networks have been trained to hit upon both leaves or canopies Everlasting of weeds. Image classification the use of ResNet-50 and VGGNet-16 was largely unsuccessful all through validation with whole pics (Fl-score < 0.04). CNN training elevated the usage of cropped photographs Eternal Broad Fall detection at some stage invalidation for VGGNet (F1-score = 0.77) and ResNet-50 (F1-Score = 0.62). The rabi crop weed leaf-trained inception V4 and EfficientNet-B7 achieved the highest F1-Score (0.94) and F1 Score (0.96) respectively, The aim of leaf-based EfficientNet-B7 extended false positives, even though such errors could be won over with extra training images for network desensitization training. Photograph-based faraway sensing rabi crop will become the most viable CNN test for weeds in competition with the EfficientNet-B7 crop.

Weed Management in White Bean With Pre-plant Incorporated Herbicides

Five field experiments were conducted in Ontario Canada during 2018-2020 to determine the level of crop injury, weed control and white bean yield with up to four-way mixtures of herbicides applied preplant incorporated (PPI). The trials were arranged in a factorial design: Factor 1 was &amp;ldquo;Grass herbicide&amp;rdquo; including no grass herbicide, trifluralin, S-metolachlor and trifluralin + S-metolachlor and Factor 2 was &amp;ldquo;Broadleaf herbicide&amp;rdquo; including no broadleaf herbicide, halosulfuron, imazethapyr and halosulfuron + imazethapyr. At 2 and 4 weeks after emergence (WAE), there was minimal (&amp;le; 4%) white bean injury. At 8 weeks after herbicide application (WAA), trifluralin, S-metolachlor or trifluralin + S-metolachlor averaged across Factor 2 controlled velvetleaf 69, 71 and 62%, respectively; halosulfuron, imazethapyr and halosulfuron + imazethapyr averaged across Factor 1 controlled velvetleaf 75, 95 and 97%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled pigweed 93, 90 and 97%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled pigweed 97, 79 and 98%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor provided poor (&amp;le; 32%) control of common ragweed while halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled common ragweed 86, 53 and 87%, respectively. The 4-way tankmix of trifluralin, S-metolachlor, halosulfuron + imazethapyr controlled common ragweed 95%. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled common lambsquarters 81, 38 and 91%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled common lambsquarters 94, 97 and 99%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor provided poor (&amp;le; 46%) control of wild mustard while halosulfuron, imazethapyr and halosulfuron + imazethapyr provided excellent (&amp;ge; 97%) wild mustard control. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled barnyardgrass 70, 85 and 94%, respectively, and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled barnyardgrass 9, 50 and 59%, respectively. At 8 WAA, trifluralin, S-metolachlor and trifluralin + S-metolachlor controlled green foxtail 89 to 98% and halosulfuron, imazethapyr and halosulfuron + imazethapyr controlled green foxtail 19, 69 and 67%, respectively. Weed interference reduced white bean yield 76%. Generally, white bean yield reflected the level of weed control. Based on these results, the 2- and 3-way tankmixes of herbicides evaluated generally provide similar weed control as the 4-way tankmixes.

Emergence and Growth of Tall Fescue Seedlings after Postemergence Broadleaf Herbicide Application

Effective weed control prior to seeding is essential for proper turfgrass establishment since competition from weeds can cause sward establishment to fail. Herbicides with multiple active ingredients from different chemical families could increase weed control efficacy, but hinder the establishment of newly seeded turf. Research trials were initiated in the fall of 2020 in Olathe and Manhattan, KS, to determine if tall fescue (Schedonorus arundinaceus) could be seeded earlier after application than stated on the herbicide labels. Overall, this study demonstrated that seeding between 0 to 14 days after an application of carfentrazone-ethyl + MCPP + 2,4-D + dicamba (SpeedZone), fluroxypyr + halauxifen-methyl + 2,4-D Choline (GameOn); or triclopyr + pyraflufen-ethyl + 2,4-D + dicamba (4-Speed XT) had little or no effect on tall fescue growth under the conditions evaluated in these experiments. In general, herbicide manufacturers must consider altering label reseeding intervals before using the results reported herein as guidelines.

Influence of hard water on 2,4-D formulations for the control of dandelion

AbstractThe herbicide 2,4-D is used in a variety of cropping systems, especially in grasses because it is a selective postemergence broadleaf herbicide. However, the most common formulation (2,4-D dimethylamine) is antagonized when mixed in hard water. The objective of this research was to determine which formulations of 2,4-D or premixes of various formulations of synthetic auxin herbicides are subject to hard water antagonism. Formulations surveyed for hard water antagonism in the first experiment included 2,4-D dimethylamine, 2,4-D diethanolamine, 2,4-D monomethylamine, 2,4-D isopropylamine salt, 2,4-D choline salt, 2,4-D isooctyl ester, and 2,4-D ethylhexyl ester. Synthetic auxin formulation types in the second experiment included water-soluble, emulsifiable concentrates and emulsion-in-water. All formulations were mixed with both soft and hard water (600 mg CaCO3 L−1) and applied to dandelions to determine whether antagonism occurred in hard water. Water-soluble (amine and choline) 2,4-D formulations were antagonized by hard water, but water-insoluble (ester) 2,4-D formulations were not antagonized. Similar results were found by formulation type with water-soluble synthetic auxin premixes antagonized but emulsifiable concentrates not antagonized. Furthermore, water-soluble salt formulations were not antagonized when formulated in premixes with other synthetic auxin herbicides as an emulsion-in-water. This research demonstrates that all 2,4-D water-soluble formulations and water-soluble premixes with phenoxycarboxylic acid herbicides are subject to hard water antagonism. Formulations of 2,4-D containing emulsifying agents protect against antagonism by the water-insoluble nature of ingredients in their formulation.

Production and Assessment of Potato Material Resistant to the Broadleaf Herbicide Bentazone

In potato cultivation, the problem of controlling broadleaf weeds could be solved with the production of plants resistant to the broadleaf herbicide bentazone. Plant tissue culture technology and herbicide screening technology were used to select bentazone-resistant potato materials and to analyse the physiological and biochemical characteristics of their resistance. Potato microtubers were used as explants. Results showed that the optimum medium for screening the resistance was the Murashige and Skoog medium + 1 mg/L indoleacetic acid + 4 mg/L zeatin + 60 mg/L bentazone (pH 5.8). Forty-one regenerated buds were obtained by screening culture. After treatment with 48% bentazone aqueous solution (700 mg/L and 1296 g a.i./ha), one resistant product was obtained. Exposure to bentazone (1296 g a.i./ha) reduced the physiological indices of both the resistant and control potato plants. However, compared with control, the photosynthetic indices and acetyl-CoA carboxylase activity of resistant selection only decreased slightly and increased significantly from the lowest level, and the content of malondialdehyde, an indicator of plant stress, was also less affected.

Removal of herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) from saline industrial wastewater by reverse osmosis and nanofiltration

Conventional reverse osmosis (RO), a novel temperature-swing RO (TSRO), and tailored nanofiltration (NF), were investigated to target the removal of the chlorophenoxy broad-leaf herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) from saline (HCl-rich) wastewater at pH between 1 and 2. Batch concentration by RO at 17.5 bar using BW30 and SW30 membranes showed similar performance, where BW30 showed rejections of 95.3% for MCPA and 25.9% for acid, but initial flux of 13 L.m−2.h−1 declined by 82% upon reaching 80% volume recovery. For the novel TSRO using BW30 and swing temperature from 24°C to 45 °C based on MCPA solubility tests, practical higher overall flux was achieved while showing similar MCPA rejection, but with slightly higher acid rejection of 37%. Pilot scale NF using NF270 and NF90 membranes showed decreased rejections of both MCPA and acid. The NF270 showed rejections of 71.3% for MCPA and 16.8% for acid. But despite lower MCPA rejection, its high flux up to 80% volume recovery could be used with RO or other treatments to meet MCPA discharge requirements. RO and NF are therefore suitable for MCPA removal from saline (HCl-rich) wastewaters, but novel temperature swing RO process offers potential to achieve higher MCPA rejection simultaneously to higher overall flux at practical volume recoveries.