Postemergence Herbicides Research Articles

Management of Glyphosate Isopropylamine-Resistant Goosegrass (Eleusine indica) Biotypes Through Pre- and Post-Emergence Herbicides

Management of Glyphosate Isopropylamine-Resistant Goosegrass (Eleusine indica) Biotypes Through Pre- and Post-Emergence Herbicides

Evaluation of post emergence herbicides spraying in maize (Zea mays L.) by using drone

Evaluation of post emergence herbicides spraying in maize (Zea mays L.) by using drone

Effect of pre-emergence and post-emergence herbicides for weed management in Mungbean [Vigna radiata (L.) Wilczek

Effect of pre-emergence and post-emergence herbicides for weed management in Mungbean [Vigna radiata (L.) Wilczek

Effect of Pre- and Post-Emergence Herbicides on Weed Control and Yield in Sunflower (Helianthus annuus L.)

Weeds are a major cause of yield and quality loss in sunflower (Helianthus annuus L.) crops. Therefore, weed control is important in sunflower production. In this context, the study was conducted in 2023 to determine the effectiveness of pre-emergence and post-emergence herbicides with different modes of action on weed population, dry weight of weeds and sunflower yield and yield components in sunflower. Four herbicides with different modes of action, three pre-emergence (aclonifen (A), pendimethalin (P), linuron (L) and one post-emergence (quizalofop-p-ethyl) (Q) and combinations of these herbicides were used in the study. To determine the effects of herbicides on weed populations and species, four different assessments were conducted at regular intervals. As a result of the study, a total of 10 weed species belonging to 5 families were detected in the trial area. The weed species with the highest density were Sorghum halepense (L.) Pers., Xanthium strumarium L., Convolvulus arvensis L. and Chenopodium album L. The study found that the effects of herbicides on weed populations and species varied. In the study, the highest rates of weed control were achieved in plots where both pre-emergence and post-emergence herbicides were used together. The highest weed control rate was observed in plots P+Q (96.66%). The highest effect on weed dry weight was obtained in plot L+Q with a rate of 89.63%. The highest weed dry weight was recorded in the weedy control plots. In the study, the highest yield (287.53 kg da-1) was obtained in the weed-free (hoe) control plot. Yield increases of 18% to 45% can be achieved by controlling weeds in sunflowers. As a result, herbicide efficacy on weed population and dry weight of weeds increased when herbicides were used in combination. Some herbicides have been shown to increase yields when used alone. However, it is important to use herbicides in combination to control more weed populations and prevent a potential resistance problem.

Assessing Herbicide-Resistance and Yield Optimization in Boro Rice (cv. BRRI dhan29) through Post-emergence Herbicides Applications

Effective weed management is crucial for achieving optimal crop performance and yield in rice cultivation. While post-emergence herbicides are commonly used to control weed population (WP), their effectiveness can vary based on the dosage and combinations applied. In this respect, an experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh, from December 2019 to May 2020 to predict herbicide-resistant weeds and assess the yield of boro (dry season irrigated) rice (cv. BRRI dhan29) in response to post-emergence herbicides. The experiment consisted of five post-emergence herbicides: Fenoxaprop-p-ethyl, Triafamone, Penoxsulam, Bispyribac-sodium, and Carfentrazone-ethyl, and four doses of herbicide: control, half of the recommended dose (RD), RD, and double the RD. Weed dry weight (DW), WP, and inhibition were significantly affected by different doses of herbicides. Ten weed species (WS) belonging to four families infested the experimental plots, with the most dominant being Echinochloa crus-galli, Scirpus mucronatus, and Scirpus articulatus. The lowest WP and DW, as well as the highest weed control efficiency (WCE), were achieved with double the RD of Penoxsulam and Triafamone, showing 91.09% and 90.13% efficiency, respectively, at 30 DAT. The tallest plants, highest number of effective tillers hill-1, highest grain yield, straw yield, biological yield, and harvest index were found with double the RD of Penoxsulam. In contrast double the RD of Triafamone produced the second-highest grain yield. Although double doses of herbicides increased yield, the variation was not significantly greater than the RD. Some weeds, particularly E. crus-galli, S. articulatus, Leersia hexandra, and Digitaria sanguinalis, survived even with double the RD of herbicides. This indicates a potential for herbicide-resistant weeds.

Response of Wheat to Pre-Emergence and Early Post-Emergence Herbicides

Response of Wheat to Pre-Emergence and Early Post-Emergence Herbicides

Agronomic and Technical Evaluation of Herbicide Spot Spraying in Maize Based on High-Resolution Aerial Weed Maps-An On-Farm Trial.

Spot spraying can significantly reduce herbicide use while maintaining equal weed control efficacy as a broadcast application of herbicides. Several online spot-spraying systems have been developed, with sensors mounted on the sprayer or by recording the RTK-GNSS position of each crop seed. In this study, spot spraying was realized offline based on georeferenced unmanned aerial vehicle (UAV) images with high spatial resolution. Studies were conducted in four maize fields in Southwestern Germany in 2023. A randomized complete block design was used with seven treatments containing broadcast and spot applications of pre-emergence and post-emergence herbicides. Post-emergence herbicides were applied at 2-4-leaf and at 6-8-leaf stages of maize. Weed and crop density, weed control efficacy (WCE), crop losses, accuracy of weed classification in UAV images, herbicide savings and maize yield were measured and analyzed. On average, 94% of all weed plants were correctly identified in the UAV images with the automatic classifier. Spot-spraying achieved up to 86% WCE, which was equal to the broadcast herbicide treatment. Early spot spraying saved 47% of herbicides compared to the broadcast herbicide application. Maize yields in the spot-spraying plots were equal to the broadcast herbicide application plots. This study demonstrates that spot-spraying based on UAV weed maps is feasible and provides a significant reduction in herbicide use.

Characterisation of low-level pyrasulfotole resistance and the role of herbicide translocation in wild radish (Raphanus raphanistrum)

The synthetic auxin 2,4-D and the 4-hydroxyphenylpyruvate dioxygenase inhibitor pyrasulfotole are phloem-mobile post-emergence herbicides, the latter applied in co-formulation with either bromoxynil (a contact herbicide causing leaf desiccation) or MCPA (another synthetic auxin). Previous studies have shown a wide range of 2,4-D translocation phenotypes in resistant populations of the agricultural weed Raphanus raphanistrum, but it was hypothesised that enhanced movement out of the apical meristem could contribute to resistance. Little is known about pyrasulfotole translocation or the effect of bromoxynil on pyrasulfotole movement. Therefore, the behaviour of pyrasulfotole and 2,4-D applied to the growing point of susceptible and resistant R. raphanistrum seedlings was assessed, along with the effect of bromoxynil on pyrasulfotole translocation. The small amount of herbicide directly contacting the growing point after spraying was sufficient to induce herbicide symptoms, and there was no enhancement of translocation away from the growing point in either pyrasulfotole- or 2,4-D-resistant populations. Bromoxynil had a slightly inhibitory effect on pyrasulfotole translocation in some populations, somewhat negating the minor differences observed among populations when pyrasulfotole was applied alone. Resistance to pyrasulfotole could not explained by enhanced metabolism or vacuolar sequestration of the herbicide. Overall, differential translocation in either the treated leaves or apical meristems does not appear to be a major determinant of resistance to pyrasulfotole or 2,4-D.

Efficacy of pre and post emergence herbicides on yield and economics of linseed (Linum usitatissimum L.)

Efficacy of pre and post emergence herbicides on yield and economics of linseed (Linum usitatissimum L.)

Cultivo de soja em área de arroz irrigado para reduzir a infestação de plantas daninhas

ABSTRACT Lowland rice in Santa Catarina (SC), Brazil, is grown as a sole crop, which has aggravated problems with weeds. In this context, the objective of this study was to evaluate the efficacy of weed management systems in soybean crops to decrease weed infestation in lowland rice production areas, using pre- and post-emergence herbicides. The experiment was conducted in Turvo, SC, from August 2021 to April 2022. A randomized block design with four replications was used, in a 6 × 5 factorial arrangement. The factors consisted of six pre-emergence herbicides treatments (S-metolachlor, diclosulam, sulfentrazone, sulfentrazone + diuron, pyroxasulfone + flumioxazin, and a control without herbicide), and five post-emergence herbicide treatments: control without herbicide, glyphosate at two rates (930 and 1,550 g a.e. ha-1), applied alone or in combination with clethodim. The herbicide sulfentrazone caused persistent phytotoxicity and resulted in the lowest soybean grain yield. The herbicide S-metolachlor was ineffective in controlling weed species, except barnyard grass, even when combined with post-emergence application. The poor control of these weed species does not result in significant interference, causing no significant decreases in grain yield of soybean crops grown in floodplain soils. The use of S-metolachlor, diclosulam, and pyroxasulfone + flumioxazin, combined with post-emergence application of glyphosate (930 g a.e. ha-1), resulted in highly effective control of barnyard grass, inhibiting weed seed production. Only the combination of glyphosate (1,550 g a.e. ha-1) with clethodim can suppress barnyard grass seed production without using pre-emergence herbicides.

Herbicide management for horseweed (Conyza spp.) control in post-emergence under flooded rice

This study aimed to assess the efficacy of commonly used post-emergence herbicides under flooded rice fields, for Conyza spp. control. The greenhouse experiment employed a factorial setup with factor A denoting the presence or absence of a water layer post-application, and factor B representing different herbicides, to C. sumatrensis. In field trials, were applied when the rice plantation was on V3 stage. Evaluations were control (%), roots and shoot dry weight of Conyza spp., as well as injury (%), number of grains per panicle, and grain yield (ha−1) of rice. The applications of imazapyr + imazapic, florpyrauxifen-benzyl, imazethapyr, penoxsulam, quinclorac, bentazon, triclopyr-butyl, saflufenacil and ethoxysulfuron followed by water layer entry led to Conyza spp. control surpassing 80% at 28 DAA. The herbicides florpyrauxifen-benzyl, quinclorac, triclopyr-butyl, and saflufenacil, without flooding after application, demonstrated Sumatran fleabane control equal to or greater than 80% at 28 DAA. Effective water layer management is crucial for Conyza spp. control in zero-grade rice cultivation areas.

Effect of post-emergence herbicides on weed dynamics and yield of soybean [Glycine max (L.) Merrill]

Effect of post-emergence herbicides on weed dynamics and yield of soybean [Glycine max (L.) Merrill]

Germination Biology of Three Cyperaceae Weeds and Their Response to Pre- and Post-Emergence Herbicides in Paddy Fields

(1) Background: Cyperaceae weeds have become a major type of weed in local paddy fields in China. (2) Methods: We assessed the impact of environmental factors, including temperature, light, salinity, water stress and soil depth, on the germination and emergence of three dominant Cyperaceae weeds: Cyperus difformis L., C. iria L. and Fimbristylis littoralis Gaudich. Using the dish dipping method, the performances of the pre- and post-emergence herbicides commonly used in paddy fields on three Cyperaceae weeds were evaluated using the pot method. (3) Results: The seeds optimally germinated at 35 °C in constant conditions and 25 °C/40 °C in alternating conditions. The seeds of the three Cyperaceae weeds were sensitive to light and could not germinate under dark conditions. The germination rate of the three weeds decreased with the increase in the NaCl concentration and water potential; the three weeds could not germinate at a 320 mmol·L−1 NaCl concentration and −0.1 MPa water potential. When the pH levels were 4 to 9, the germination rates of the three weeds were all greater than 80%. The burial depths to inhibit 50% of the emergence of C. difformis, C. iria and F. littoralis were 0.27, 1.06 and 0.42 cm, respectively. The control efficacy of the pre-emergence herbicides of pretilachlor, butachlor and oxyfluorfen on the three weeds were all above 90% at the recommended dose in the field. Halosulfuron-methyl, florpyrauxifen-benzyl and bentazone could effectively control the three Cyperaceae weeds; their performances on the three weeds at the 3- to 4-leaf stage were all above 82%. (4) Conclusions: The three Cyperaceae weed seeds have a strong adaptability to temperature, water potential, salinity and soil depth, and these weeds are sensitive to most pre- and post-emergence herbicides. Therefore, taking Cyperaceae weed seeds into the deep soil layer by tillage or selecting appropriate herbicides according to their growth stages can effectively control Cyperaceae weeds in rice fields.

Poa annua control in golf course putting green collars via fraise mowing

AbstractPoa annua L. control on golf courses is challenging, particularly in collars adjacent to putting greens where herbicide options are limited. Field research was conducted in Knoxville, TN from 2022 to 2024 to evaluate P. annua control efficacy following summer fraise mowing of putting green collars. Plots were arranged in a hybrid bermudagrass [C. dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy, cv. ‘Tifway’] collar adjacent to a creeping bentgrass (Agrostis stolonifera L.) putting green. A walk‐behind fraise mower (RR600 HDX; SISIS) was used to fraise mow plots (0.6 × 3 m) to depths of 8 or 15 mm. A non‐fraise‐mowed check (0 mm) was included for comparison. Plots were fraise mowed on June 20, 2022 and July 10, 2023 with recovery visually assessed thereafter relative to non‐fraise‐mowed check plots in each replication. Poa annua control was visually assessed 133 and 233 days after treatment relative to non‐fraise‐mowed check plots as well. In the absence of herbicide, summer fraise mowing of hybrid bermudagrass collars provided effective control (>89%) of P. annua for 133 days. Hybrid bermudagrass recovery from this mechanical control method was swift, which suggests that it could be incorporated into a weed management program with pre‐ and postemergence herbicides similar to harvest weed seed control methods used in crop production.

Two-Pass Weed Management Programs for White Bean

It is essential to implement effective weed management programs to minimize white bean yield loss from weed interference. Four field experiments were conducted during 2022 and 2023 to determine the efficacy of one-pass compared to two-pass weed control programs. This study evaluated trifluralin + S-metolachlor + imazethapyr or trifluralin + S-metolachlor + halosulfuron applied preplant incorporated (PPI), bentazon + fomesafen + quizalofop-p-ethyl applied postemergence (POST), and trifluralin + S-metolachlor + imazethapyr or trifluralin + S-metolachlor + halosulfuron applied PPI followed by (fb) bentazon + fomesafen + quizalofop-p-ethyl applied POST in white bean. There was minimal white bean injury (≤ 5%) with the herbicide programs evaluated. Weed interference decreased white bean yield 44%. Weed interference with bentazon + fomesafen + quizalofop-p-ethyl applied POST resulted in a 24% decrease in white bean seed yield compared to the weed-free control; however, all other PPI and PPI fb POST herbicide programs resulted in white bean seed yield that was similar to the weed-free control. Weed interference with the one-pass herbicide programs (PPI or POST) resulted in 17% lower white bean seed yield compared to the two-pass herbicide programs (PPI fb POST). Trifluralin + S-metolachlor + imazethapyr, applied PPI, controlled velvetleaf 85%, common ragweed 35%, common lambsquarters 96%, and green foxtail 80% at 8 weeks after the POST application (WAT). Trifluralin + S-metolachlor + halosulfuron, applied PPI, controlled velvetleaf 68%, common ragweed 87%, common lambsquarters 94% and green foxtail 56% at 8 WAT. Bentazon + fomesafen + quizalofop-p-ethyl, applied POST, controlled velvetleaf 86%, common ragweed 97%, common lambsquarters 34%, and green foxtail 29% at 8 WAT. Trifluralin + S-metolachlor + imazethapyr, applied PPI, followed by bentazon + fomesafen + quizalofop-p-ethyl, applied POST, controlled velvetleaf, common ragweed, common lambsquarters, and green foxtail 98, 97, 96, and 94%, respectively at 8 WAT. Trifluralin + S-metolachlor + halosulfuron, applied PPI, followed by bentazon + fomesafen + quizalofop-p-ethyl, applied POST, controlled velvetleaf, common ragweed, common lambsquarters, and green foxtail 97, 99, 97 and 93%, respectively at 8 WAT. Based on orthogonal contrast, the two-pass herbicide programs provided 17, 21, 20, and 38% greater control of velvetleaf, common ragweed, common lambsquarters, and green foxtail in comparison to the one-pass herbicide programs, respectively at 8 WAT. This study concludes that the two-pass herbicide programs of trifluralin + S-metolachlor + imazethapyr or trifluralin + S-metolachlor + halosulfuron applied PPI followed by bentazon + fomesafen + quizalofop-p-ethyl applied POST provides the most consistent weed control in white bean in Ontario.

Five years of conservation tillage and weed management in a rice-chickpea rotation of northern Gangetic Plains of India: Weed growth, yield benefits and economic profitability

Cropping system diversification of cereal-cereal systems with alternative systems preferably with pulses/legumes is demand of time across the globe for sustenance of natural resources and climate resilience. Rice-chickpea has been advocated as a futuristic cropping system in rice ecologies of South Asia for diversification of dominating rice-wheat system. However, the long-term sustainability of this system with respect to weed severity/growth, crop/system productivity, profitability, and yield stability under variable tillage, crop residues, and weed management practices has not been studied elaborately. Hence, present study was undertaken for five consecutive years in split-plot design with four tillage and residue management practices in main plot (conventional and zero tillage with and without residues), and three weed control practices (pre + post emergence herbicides and manual weeding) in sub-plot. Conservation tillage system comprising zero-tilled (ZT) direct seeded rice (ZTDSR) - ZT chickpea with rice residue retention (ZTDSR-ZTC+RR) led to the lower weed density in chickpea (by 10 %) and system (by 7 %) than conventional-tilled (CT) puddled transplanted rice - CT chickpea without residues (PTR-CTC-R; farmer practice). Among weed management practices, pendimethalin 1 kg a.i. ha−1 – metsulfuron-methyl + chlorimuron ethyl (ready-mix) 4 g a.i. ha−1 in rice and oxyfluorfen 150 g a.i. ha−1 – propaquizafop 100 g a.i. ha−1 in chickpea decreased the weed density in system by 14–22 % (p < 0.05) than pendimethalin + one hand weeding. The best weed management practice (pendimethalin – metsulfuron-methyl + chlorimuron ethyl) had significantly total weed density rice (by 7 %) and system (by 10 %) than current recommendation of the Indo-Gangetic Plains region (pendimethalin - bispyribac-sodium). It suggested that rotation of bispyribac-sodium with metsulfuron-methyl+chlorimuron ethyl (mixture herbicide) could reduce weed density and increase yield over time. Mean of five years indicated a non-significant yield difference among conservation and conventional tillage systems in rice. However, conservation tillage practice (ZTDSR-ZTC+RR) had 10 % higher chickpea yield and 4 % higher system yield (five years mean) over the PTR-CTC-R (p < 0.05). Further, conservation tillage comprising ZT in both crops in system with added residues (ZTDSR-ZTC+RR) resulted in an economic benefit of INR 22,000 than the conventional tillage in both crops without residues (PTR-CTC-R). Moreover, five years sustainable yield index was 16 % higher in ZTDSR-ZTC+RR system than conventional-tilled rice-chickpea system. Thus, conservation tillage with suitable pre- + post- emergence herbicides such as pendimethalin – metsulfuron-methyl + chlorimuron ethyl in rice and oxyfluorfen – propaquizafop in chickpea can reduce the weed density and enhance the crop and system productivity over time than conventional tillage. This system can also sustain the yields of component crops and system in long-run with higher yield stability over conventional tillage without residues. This system can be adopted in the cereal-cereal based cropping system of rice ecologies to diversify the system and to reverse the weed infestation and yield decline.

Optimizing herbicide types and concentrations: Crucial elements for achieving intensive cultivation of common buckwheat

An appropriate herbicide type and concentration is essential for effective weed management and enhancing crop yield. However, the optimal herbicide type and corresponding application concentration for controlling weeds in common buckwheat on the Loess Plateau region of Northwestern China remain unclear. To address this gap, experiments were conducted to investigate the effects of various herbicides on weed control, dry matter accumulation, and grain yield in common buckwheat, and to analyze the variances in weed control efficacy and grain yields of the optimal herbicides at different concentrations. The results showed that both metolachlor and quizalofop-P-ethyl demonstrated effective weed control with lower phytotoxicity. Dry matter accumulation was lower under metolachlor, with no significant differences observed among the post-emergence herbicide treatments. Importantly, metolachlor and quizalofop-P-ethyl promoted the allocation of dry matter to grains. Remarkably, metolachlor and quizalofop-P-ethyl increased the grain yield by 15.59% and 26.97%, respectively, compared to spraying an equivalent amount of water. Additionally, the m2.25, q0.9, and q1.2 treatments exhibited excellent weed control effectiveness. And the higher grainnumber per plant observed under m2.25, q0.9, and q1.2 contributed to the increase in grain yield. Consequently, m2.25, q0.9 and q1.2 increased the grain yield by 34.42%, 38.86% and 33.16%, respectively. These findings demonstrate that applying metolachlor and quizalofop-P-ethyl at 2.25 L ha−1 and 0.9 or 1.2 L ha−1 respectively, is beneficial for efficient weed management and yield enhancement in common buckwheat cultivation on the Loess Plateau region of Northwestern China. These studies provide important guidance for promoting common buckwheat cultivation in this region.

Assessing the effectiveness and evolution of pre and post-emergence herbicides in weed management for coriander (Coriandrum sativum L.)

Assessing the effectiveness and evolution of pre and post-emergence herbicides in weed management for coriander (Coriandrum sativum L.)

THE INFLUENCE OF HERBICIDE PROTECTION TECHNOLOGIES ON ECONOMICALLY VALUABLE TRAITS AND YIELD OF SUNFLOWER HYBRIDS IN THE CENTRAL FOREST-STEPPE OF UKRAINE

In the conditions of the Central Forest-Steppe of Ukraine during 2021–2023, the influence of herbicide protection technologies on the formation of plant height, basket diameter, oil content and yield of sunflower hybrids was studied. Twelve sunflower hybrids were studied: SY Bacardi CLP, NK Kondi, SUZUKA (Syngenta Crop Protection AG), LG5555 CLP, LG5580, LG59580 (Limagrain Europe), ЕS GENESIS, ES Bellamis CL, ES AROMATIC SU (Euralis Semences), P64LP130, PR64F66, P64LE25 (Pioneer Overseas Corporation). Sunflower hybrids were studied using classical, Express (or SUMO), Clearfield® Plus (CLP) herbicide protection technologies. Taking into account the agrometeorological conditions of sunflower hybrids cultivation and their genetic potential, it was found that under the Express Sun (or SUMO) herbicide protection technology of Dupont (consisting of sunflower hybrids resistant to tribenuron-methyl-based products), the most stable was the height of sunflower plants in SUZUKA (194–197 cm) and P64LE25 (206–207 cm) hybrids. According to the technology of herbicide protection Clearfield® Plus (CLP) by BASF (based on the resistance of sunflower hybrids to herbicides of the imidazoline group), the highest stability in plant height was shown by the hybrid LG5555 CLP (175–177 cm). According to the classical technology, using soil and post-emergence herbicides and graminicides with elements of mechanical control, the hybrid ES Bellamis SL had the greatest variation in plant height from 177 cm to 223 cm during the three years of research. The most stable was the diameter of the sunflower basket in the hybrid SI Bacardi CLP (22.3–22.5 cm) with Clearfield® Plus (CLP) herbicide protection technology. According to the Express Sun (or SUMO) herbicide protection technology, high indicators of the basket diameter were obtained in the hybrids ES AROMATIC SU (20.7–23.2 cm) and SUZUKA (19.3–23.3 cm). The highest yields per plot were recorded for hybrids SUZUKA (11.15 kg), ES AROMATIC SU (11.05 kg) and P64LE25 (10.84 kg) using Clearfield® Plus (CLP) herbicide protection technology. The hybrids that provided the best yields and formed high quality seeds were P64LE25 (3.86 t/ha), with an oil content of 47.2%; ES AROMATIC SU (3.95 t/ha), with an oil content of 47.1%; and SUZUKA (3.98 t/ha), with an oil content of 47.7%, using Clearfield® Plus (CLP) herbicide protection technology. With Express Sun (or SUMO) technology, the best hybrid was LG5580 (4.0 t/ha), with an oil content of 48.6%.

Efficacy of Sequential Applications of Pendimethalin 500 EC (Pendimight®) and Oxyfluofen 240 EC (Harris®) for Weed Control in Direct Seeded Onion (Allium cepa L.) in Sudan

A field study was carried out to evaluate the efficacy of pendimethalin 500 EC (trade name: Pendimight®) and oxyfluorfen 240 EC (trade name: Harris®) to control weeds in direct-seeded onion (Allium cepa L.). Pendimethalin and oxyfluorfen were applied solely at reduced rates (1.35 and 0.17 kg a.i. ha-1), and at the recommended rates (1.8 and 0.25 kg a.i. ha-1) as pre-and post-emergence herbicides, respectively. Both herbicides were also applied sequentially at the same doses. Ten weeks after sowing (WAS), the application of pendimethalin alone provided better weed control (62% - 65%) than oxyfluorfen alone (33% - 43%) when they were applied at the lower and recommended rates, respectively. Sequential applications of the two herbicides as pre-and post-emergence herbicides, outperformed applications of the two herbicides alone, and resulted in the best weed control (79% to 85%), lowest weed dry weight (18.35 to 35.60 g.m-2), significantly increased plant height and the number of leaves per plant, and resulted in a ten-fold higher onion yield (24.64 to 26.37 t. ha-1) compared with the Un-weeded control (2.27 t. ha-1). There were no significant differences observed between the treatments on the emergence (%) of onion seeds and the survival of onion seedlings. Sequential applications of pendimethalin and oxyfluorfen is a promising techniques for weed control in direct-seeded onions in Sudan.