Pre-emergence Application Research Articles

Integrating sequential applications of residual and postemergence herbicides for controlling Carolina redroot (Lachnanthes caroliniana) in cranberry beds

Abstract Carolina redroot (LAHTI) is a perennial weed of New Jersey cranberry beds. It is associated with “stand opening” areas that result from fairy ring dieback or other conditions of natural and anthropogenic origin. LAHTI accounts for significant yield reduction through direct competition with cranberry for nutritional resources. Field experiments were conducted from 2017 to 2022 on ‘Ben Lear’ and ‘Early Black’ cranberry beds in Chatsworth, NJ, to determine 1) the efficacy of residual herbicides labeled for use on cranberry, and subsequently, 2) to evaluate the value of overlapping preemergence applications of napropamide and postemergence applications of mesotrione for LAHTI control while minimizing crop phytotoxicity. Treatments in the first experiment included preemergence applications of dichlobenil or norflurazon at 2.2 and 4.5 kg ha−1 and napropamide a 6.7 kg ha−1. In the second trial, napropamide was applied preemergence annually to plots at 6.7 or 10.1 kg ha−1 either as a single or as two equally or unequally split applications spaced 30 d apart, followed by or not followed by mesotrione applied postemergence at 280 g ha−1 when LAHTI leaves emerged above the cranberry canopy. The preemergence herbicides dichlobenil applied at 4.5 kg ha−1 and napropamide provided ≥48% LAHTI control and ≥40% LAHTI biomass reduction 112 d after treatment (DAT), whereas norflurazon had no significant effect on LAHTI biomass. Less than 4% of crop injury and liquid formulation adapted to chemigation identified napropamide as an effective preemergence herbicide for LAHTI control. In the second trial, napropamide applied at 10.1 kg ha−1 followed by an application of mesotrione reduced LAHTI biomass by ≥73%. Splitting napropamide application reduced yield by 36% and berry weight by 12% compared with a single application at the dormant stage. Compared with the nontreated control, a single napropamide application at 10.1 kg ha−1 followed by an application of mesotrione increased yield by 38%. Information derived from these studies is already being used by growers to enhance the productivity and profitability of New Jersey cranberry fields.

Influence of Weed Management Practices and Biochar on Weed Dynamics of Fenugreek (Trigonella foenumgraecum L.)

A field experiment was conducted at Instructional farm, Rajasthan College of Agriculture, MPUAT, Udaipur (Rajasthan) during rabi season 2021-22 and 2022-23 to study the influence of weed management practices and biochar on weed dynamics of fenugreek. The experiment consists of eight weed management treatments and three biochar levels thereby involving 24 treatment combinations replicated thrice in factorial randomized block design. The pooled results revealed that pre-emergence application of oxyfluorfen 120 g ha-1 recorded significantly lowest density and dry matter of narrow-leaved, broad-leaved and total weeds and highest weed control efficiency (78.28%).

Weed Management Practices on Growth, Yield and Economics of Kharif Grain Sorghum

In the Kharif grain sorghum growing areas of Karnataka, the sorghum production suffers greatly due to weed problem, which offers limitations to crop. It was found that weed infestation become unmanageable throughout the growing period by the traditional methods of interculturing and manual weeding due to continuous and heavy rains during entire vegetative and early reproductive stages of Kharif sorghum. Hence, integration of herbicides with some cultural operations and use of pre-emergence, post-emergence herbicides in combination with mechanical methods can prove to be more successful. A field experiment entitled “Weed management in kharif grain sorghum” was conducted during Kharif 2019 at ARS, Hagari in deep black soil with neutral reaction (pH 7.50), organic carbon (5.5 g kg-1), available nitrogen (248.00 kg ha-1), available phosphorus (36.75 kg ha-1) and available potassium (312.00 kg ha-1). An experiment was laid out in Randomized Complete Block Design (RCBD) with three replications. There were fourteen treatments comprising of weed management practices. The dominant weeds observed in the experimental fields were among grasses Brachiaria reptans, while in broad leaved weeds, Amaranthus viridis and among sedges, Cyperus rotundus. Significantly lower population of grasses, sedges, and broad leaved weeds, weed dry weight, weed index (%) and higher weed control efficiency throughout the crop growth period was noticed in sequential pre-emergence application of atrazine 50 WP @ 0.50 kg a.i. ha-1 as PE fb 2,4-D Na Salt 80 WP @ 0.75 kg a.i. ha-1 as PoE at 25 DAS except weed free treatment. Atrazine 50 WP @ 0.50 kg a.i. ha-1 as PE fb 2,4-D Na Salt 80 WP @ 0.75 kg a.i. ha-1 as PoE at 25 DAS recorded significantly higher plant height, dry matter accumulation, leaf area, test weight, grain yield, straw yield, harvest index, gross return, net return and benefit cost ratio (160.8 cm, 183.4 gplant-1, 24.1 dm2 plant-1, 30.53 g, 4195 kg ha-1, 9891 kg ha-1, 29.80 %, Rs. 1,03,675ha-1, Rs. 71,636 ha-1and 3.24, respectively) except weed free and it was on par with atrazine 50 WP @ 0.50 kg a.i. ha-1 as PE fb IC at 25 DAS and HW at 25 DAS and IC at 40 DAS.

Postemergence-directed applications of pendimethalin for control of early-season weeds in chile pepper

Abstract 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 pendimethalin in combination with herbicides registered for preemergence applications. The greenhouse study included three treatments administered when chile pepper was at the four-leaf stage: (i) pendimethalin applied to foliage and soil, (ii) pendimethalin applied to soil only, and (iii) a nontreated control. The field study included four treatments: (i) preemergence applications of napropamide followed by postemergence-directed pendimethalin at 5 wk after crop seeding, (ii) preemergence applications of clomazone followed by postemergence-directed pendimethalin at 5 wk after crop seeding, (iii) postemergence-directed pendimethalin without preemergence herbicides, and (iv) nontreated, weed-free control. We conducted the field study at two sites that differed in soil texture. Pendimethalin application rates were maximum labeled 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, or root area. Results from the field study indicated that postemergence-directed pendimethalin did not affect chile pepper height or fruit yield, or cause visible symptoms of herbicide injury. Postemergence-directed pendimethalin reduced the densities of weeds, including junglerice. The results of this study indicate that postemergence-directed applications of pendimethalin at 5 wk after crop seeding do not cause crop injury or yield loss in chile pepper, while providing some weed control benefits.

Influence of Integrated Weed and Nutrient Management on Productivity and Profitability of Summer Maize (Zea mays) Under Rainfed Condition of Assam, India

A field experiment was conducted at the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat during the summer season of the year 2020 to evaluate the effects of integrated weed and nutrient management on weed growth, yield attributes and yield of summer maize. The experiment was laid out in factorial randomized block design and replicated thrice. The treatment consisted of three nutrient management practice viz., 100% RDF (N1); N1+ 25 kg ZnSO4/ha (N2) and 75 % RDN and 100 % P2O5 and K2O through chemical fertilizer (CF) + 25 % N through vermicompost + 25 kg ZnSO4/ha (N3) and four weed management practices viz., weedy check (WM1), live mulching with cowpea (WM2), WM2 + hand weeding at 25 and 45 DAS (WM3) and Atrazine 500g+Pendimethalin 500g/ha followed by hand weeding at 45 DAS (WM4). Experimental findings revealed that the different INM practices significantly affected the growth parameters, yield and yield attributes of summer maize. The maximum values of growth parameters were recorded in the treatment involving application of 75 % RDN and 100 % P2O5 and K2O through chemical fertilizer + 25 % N through vermicompost + 25 kg ZnSO4/ha (N3). Similarly, yield and yield attributing characters viz., weight of cob with and without husk, length of cob without husk, number of rows per cobs, grain per row, grain per cob, 1000 grain weight, shelling percentage, grain (23.76 q/ha) and stover (74.55 q/ha) yield. The growth, yield and yield attributing parameters of maize were significantly affected by the different weed management practices. Pre emergence application of Atrazine 500g+Pendimethalin 500g/ha followed by hand weeding at 45 DAS (WM4) resulted the highest value of yield. The highest grain (21.77 q/ha) and stover (71.12 q/ha) yield were recorded in the treatment WM4.The interaction effects of different nutrient and weed management practices were found not significant. The economic study revealed that the highest gross return (₹.1, 03816.00/ha), net return (₹.67, 956.00) and B: C (1.90) were recorded from the treatment combination N3WM4.

Performance evaluation of Oxadiargyl for effective weed management in sunflower

A field experiments with the objective to determine the performance evaluation of Oxadiargyl for effective weed management in sunflower was conducted under irrigated condition. The experiment was laid out in randomized block design consisting of nine treatments and replicated thrice. Weed free environment produced higher growth and yield parameters, however it’s on par with the other treatments T2 and T3 which are having combination of herbicide followed by hand weeding. Pre emergence application of Oxadiargyl @ 125g ai/ha fb hand weeding gave excellent control of all the weeds at all the stages of the crop and it recorded higher weed control efficiency and the lowest weed index. Highest net returns of Rs. 26,151/ha and benefit cost ratio of 1.47 was observed in Pre emergence application of Oxadiargyl @ 125g ai/ha fb hand weeding at 30 DAS.

Evaluation of the Impact of Herbicidal Weed Management Practices on Weed Density, Yield Attributes and Yield of Irrigated Chickpea (Cicer arietinum L.)

In the Rabi season of 2021-22, an experiment was conducted at the Agronomy Research Farm of CCS Haryana Agricultural University in Hisar. The aim was to examine how herbicidal weed management affects irrigated chickpea. The experiment was laid out in Randomised Block Design (RBD) with thirteen treatments, each repeated three times. The treatments included various herbicides applied at different stages, such as pre-plant incorporation (PPI), pre-emergence (PRE), and post-emergence (POE). Interestingly, the Ready mix (RM) herbicide application of pendimethalin + imazethapyr (RM) @ 1000 g a.i ha-1, applied both as PPI and PRE, outperformed the herbicides applied solely as PPI, PRE, or POE. Among the herbicidal treatments, the combined during PPI and PRE stages exhibited excellent control over a diverse weed population, leading to a significant increase in chickpea yield compared to the weedy check. The number of seeds per pod, pods per plant, and branches per plant varied significantly with different weed control treatments. Weed-free plots showed the highest values in these parameters. The uncontrolled growth of weeds in the weedy check resulted in a 55.2% reduction in seed yield as compared to weed-free plots. The maximum seed yield (1968 kg ha-1) and favorable yield attributes were observed in the weed- free treatment, statistically comparable to the yield obtained from two hand weeding at 30 and 50 days after sowing (1940 kg ha-1). Among herbicidal treatments, the highest seed yield was achieved with the PRE application of pendimethalin + imazethapyr (RM) @ 1000 g a.i. ha-1 (1827 kg ha-1). The dominant weed flora consisted of Chenopodium album, Fumaria parviflora and Anagallis arvensis. Density of different weed species was significantly influenced by different weed control treatments. All the weed control treatments significantly reduced the total weed density and dry matter accumulation by weeds in comparison to weedy check. Weed free and two hand hoeing reduced the weed population drastically which was statistically at par with PRE application of pendimethalin + imazethapyr (RM) at 1000 g a.i. ha-1. Chenopodium album, Fumaria parviflora and Anagallis arvensis were effectively controlled by RM irrespective of its time of application.

Study To Evolve Technology For Controlling Binding Weeds In Grown-Up Sugarcane Crop

Field investigations were carried out at Sugarcane Research Station, Cuddalore Tamil Nadu Agricultural University, to evolve technology for controlling binding weeds in grown-up sugarcane crops during 2015-18. The experiments were laid out in Randomized Block Design with three replications and the sugarcane variety tested wasCoC(SC)24. The treatments constituted of T1 – PE. atrazine @ 1.0 kg/ha and Po.Emetribuzin 0.75 kg/ha @ 60 DAP, T2 – PE atrazine 1.0 kg/ha and Po.E 2,4D Na salt 1.25kg/ha @ 60 DAP, T3 – P.E atrazine 1.0 kg/ha followed by weeding and earthing up on 75 DAP, T4 – Mechanical weeding by power tiller (45, 90 and 120 DAP), T5 – Intercropping of sun hemp and its incorporation as insitu on 60 DAP, T6 – Detrashing and mulching at 150th&210th DAP, and T7 – hand weeding and manual removal of weeds on 45, 90 and 120th days and T8 – Control. Based on the performance of herbicides, the Pre-emergence application of atrazine @ 1.0 kg a.i/ha followed bypost-emergence application of metribuzin @ 0.75 kg/ha on 60 days after planting was the best treatment for controlling weeds in grown-up sugarcane and also the yield attributes increased in sugarcane compared to control. The critical period of weed crop competition in sugarcane ranged between 27 and 50 days (Srivastava et al., 2003). Sugar yield as well as juice quality greatly affected by the application of weed control treatments. The presence of weeds in the sugarcane fields and no control has also led to a decrease in sugar yield (Roshan et al., 2006.; Patel et al., 2007; Kanchan, 2009) in proportion of sucrose, purity and brix ( Bahadar et al., 2004; Annual Report, 2012) . Generally, the increase in by weed growth one kilogram corresponds to a reduction in one kilogram of the crop. The reduction in cane yield due to weeds ranged from 40-60% (Kadam et al., 2011).

Nontarget Effects of Preemergence Herbicide Diuron in Hamlin and Valencia Sweet Orange (Citrus sinensis L. Osbek) in Florida

The prevalence of Huanglongbing (HLB) disease, also known as citrus greening, has compelled the citrus industry to change management practices to increase production. However, these changes, such as enhanced nutrition and irrigation programs, have caused weed proliferation, subsequently leading to increased use of herbicides. Thus, our study evaluated a popular preemergence herbicide active ingredient, diuron, for nontarget impacts on young Hamlin and Valencia sweet orange (Citrus sinensis L. Osbek) trees in two commercial orchards in southwest Florida. The treatments included the preemergence application of diuron at three rates (1.8, 3.6, and 7.3 kg a.i./ha), a weed-checked control (using postemergence herbicides: glufosinate ammonium + saflufenacil), and a nontreated control. The treatments were applied twice (in Fall 2021 and Spring 2022) in a randomized complete block with four replicates. Results indicate that over a 5-month period, the application of diuron generally had no significant impact on citrus root growth. Further, over a 2-month observation period for Hamlin and a 4-month observation period for Valencia, it was found that diuron application had no notable effect on fruit detachment force. Valencia trees treated with diuron high showed higher HLB disease severity at location 1. In addition, Hamlin trees treated with diuron low and medium showed higher fruit drop (∼19% more) than the untreated control at location 1. However, this trend was inconsistent across the locations and cultivars. This result suggests that increased disease severity and fruit drop were not associated with diuron treatment. Thus, our study finds diuron as a tree-safe option for preemergence weed suppression in citrus production, as long as it is used in accordance with the recommended dosage and restrictions stated on the herbicide label.

A systematic review of chemical weed management in peanut (Arachis hypogaea) in the United States: challenges and opportunities

AbstractHerbicides are the primary tool for controlling weeds in peanut (Arachis hypogaea L.) and are crucial to sustainable peanut production in the United States. The literature on chemical weed management in peanut in the past 53 yr (1970 to 2022) in the United States was systematically reviewed to highlight the strengths and weaknesses of different herbicides and identify current research gaps in chemical weed management. Residual weed control in peanut is achieved mainly with dimethenamid-P, ethalfluralin, pendimethalin, and S-metolachlor. More recently, the use of the protoporphyrinogen oxidase inhibitor flumioxazin and acetolactate synthase inhibitors, such as diclosulam, for residual weed control in peanut has increased considerably. Postemergence broadleaf weed control in peanut is achieved mainly with acifluorfen, bentazon, diclosulam, imazapic, lactofen, paraquat, and 2,4-DB, while the graminicides clethodim and sethoxydim are the major postemergence grass weed control herbicides in peanut. Although several herbicides are available for weed control in peanut, no single herbicide can provide season-long weed control due to limited application timing, lack of extended residual activity, variability in weed control spectrum, and rotational restrictions. Therefore, effective weed management in peanut often requires herbicide mixtures and/or sequential application of preplant-incorporated, preemergence, and/or postemergence herbicides. However, the available literature showed a substantive range in herbicide efficacy due to variations in environmental conditions and flushes of weed germination across years and locations. Despite the relatively high efficacy of herbicides, the selection of herbicide-resistant weeds is another area of increasing concern. Future research should focus on developing new strategies for preventing or delaying the development of resistance and improving herbicide efficacy within the context of climate change and emerging constraints such as water shortages, rising temperatures, and increasing CO2 concentration.

UAV-based Herbicide Application for Efficient Weed Management in Direct-seeded Rice

Background: Weeds are the key pest, which reduce crop productivity. Direct-seeded rice is very prone to early-stage weed infestation during initial crop development. Cultural and mechanical methods are difficult due to unavailability of labour and poor work efficiency. Hence, use of herbicides is an effective method for timely weed control. However, the efficacy of agrochemicals depends on the efficiency of spraying equipment. Conventional knapsack sprayers are used most often to spray herbicides but they are highly time-consuming, labour intensive and labour drudgery practices. Hence, the current experiment was aimed to study the efficiency of unmanned aerial vehicles (UAVs) on weed management. Methods: A field experiment was conducted at Tamil Nadu Agricultural University, Coimbatore during summer, 2022 to evaluate the efficacy of UAV-based herbicide application in direct-seeded rice. The study comprised of five weed management treatments such as pre emergence application of pretilachlor with safener and pyrazosulfuron through both UAV and knapsack sprayer and unweeded check as control. The experimental plot was laid out in a randomized block design with four replications. Result: The experimental findings showed that the application of pre-emergence pretilachlor significantly reduced the density and dry weight of grasses, sedges and broad leaved weeds in knapsack application. Moreover, it was found on par with UAV application of same herbicide without any phytotoxicity to rice seedlings. From the experiment, the application of pre-emergence pretilachlor through UAV is found to be more effective for timely weed control during early stages in direct-seeded rice, which reduce the labour intensity and drudgery than knapsack application.

Effect of different herbicide spray volumes on weed control efficiency of a battery-operated Unmanned aerial vehicle sprayer in transplanted rice (Oryza sativa L.)

The effect of spray volume on weed control in transplanted rice ecosystems using the Unmanned aerial vehicle (UAV) needs to be better understood for management in the advancements of UAV-based spraying technology. The present study aimed to find out the influence of varied spray volumes of 15 L/ha, 20 L/ha and 25 L/ha using the UAV and 500 L/ha using a Knapsack sprayer (KS) to compare the weed density, weed dry matter and weed control efficiency and yield in transplanted rice (Oryza sativa L.). Pre-emergence (PE) application of Pyrazosulfuron-ethyl at 25 g a.i./ha at three days after transplanting (DAT) and post-emergence (PoE) application of Bis-pyribac sodium at 25 g a.i./ha at 25 DAT were used as herbicide treatments. The results revealed that varied spray volumes significantly influenced the weed density, dry matter, and weed control efficiency of the UAV and KS. Application of herbicides using KS (500 L/ha) and UAV (25 L/ha) had better control on the weeds by reducing weed density and dry matter at 20, 40, and 60 DAT, with no significant difference. Higher grain yield and straw yield were recorded in KS (500 L/ha) and UAV (25 L/ha), with no significant difference. However, applying 25 L/ha had better weed control efficiency and higher yield, possibly due to optimum deposition. Considering the low volume application of UAV (25 L/ha) as compared with KS (500 L/ha), it is better to go for the optimal application of 25 L/ha, which is an energy-efficient and cost-effective, labour-saving approach compared to KS.

A Study in Scaffold Hopping: Discovery and Optimization of Thiazolopyridines as Potent Herbicides That Inhibit Acyl-ACP Thioesterase.

In the search for new chemical entities that can control resistant weeds by addressing novel modes of action (MoAs), we were interested in further exploring a compound class that contained a 1,8-naphthyridine core. By leveraging scaffold hopping methodologies, we were able to discover the new thiazolopyridine compound class that act as potent herbicidal molecules. Further biochemical investigations allowed us to identify that the thiazolopyridines inhibit acyl-acyl carrier protein (ACP) thioesterase (FAT), with this being further confirmed via an X-ray cocrystal structure. Greenhouse trials revealed that the thiazolopyridines display excellent control of grass weed species in pre-emergence application coupled with dose response windows that enable partial selectivity in certain crops.

Unveiling the efficacy of pre-emergent application of young Eucalyptus globulus leaves as a weed control strategy: Bridging macroscopic effects and cellular responses

Allelopathy, the inhibition of neighbouring plant growth by certain plants, can be particularly useful if applied in a targeted way for weed management. So, this study aimed to assess and characterize the herbicidal activity of fresh and dried leaves from young Eucalyptus globulus Labill. trees applied as a soil amendment. For this, fresh and dried leaves (FL and DL, respectively) were incorporated into the soil at different concentrations (0, 1, 5, and 10% w/w), where Portulaca oleracea L. seeds were sown. After 5 weeks of exposure, results revealed that the soil incorporation of DL at 10% (w/w) presented the strongest herbicidal properties, inhibiting seed germination by 63% and inducing the loss of cell viability. To unravel the possible mode of action and the main targets at both cellular and subcellular levels, an in vitro experiment was performed. Purslane seeds were sown in a nutritive medium containing different dilutions of an aqueous extract prepared with dried eucalyptus leaves. After 5 days of exposure, germinated seedlings were processed for transmission electron microscopy and histological analyses as well as for reactive oxygen species (ROS) in vivo detection by confocal laser scanning microscopy. Results revealed that the allelochemical release from DL induced ROS overproduction, resulting in the loss of cell integrity and organization, which was characterized by damage to several cellular sub-structures, along with enhanced accumulation of lipid droplets. Overall, the incorporation of DL into the soil can represent a sustainable alternative to reduce synthetic herbicide application and subsequent environmental contamination.

Impact of cereal rye cover crop on the fate of preemergence herbicides flumioxazin and pyroxasulfone and control of Amaranthus spp. in soybean

AbstractPreemergence herbicides associated with cereal rye (Secale cereale L.) cover crop (hereafter “cereal rye”) can be an effective waterhemp [Amaranthus tuberculatus (Moq.) Sauer.] and Palmer amaranth (Amaranthus palmeri S. Watson) management strategy in soybean [Glycine max (L.) Merr.] production. Delaying cereal rye termination until soybean planting (planting green) optimizes biomass production and weed suppression but might further impact the fate of preemergence herbicides. Limited research is available on the fate of preemergence herbicides applied over living cereal rye in the planting green system. Field experiments were conducted in Illinois, Kansas, Pennsylvania, and Wisconsin to evaluate the fate of flumioxazin and pyroxasulfone and Amaranthus spp. residual control under different cover crop management practices in soybean in 2021 and 2022 (8 site-years). A flumioxazin + pyroxasulfone herbicide premix was applied preemergence at soybean planting under no-till without cereal rye, cereal rye early terminated before soybean planting, and cereal rye terminated at soybean planting. Flumioxazin and pyroxasulfone concentrations in the soil were quantified at 0, 7, and 21 d after treatment (DAT), and Amaranthus spp. density was determined at postemergence herbicide application. The presence of cereal rye biomass intercepted flumioxazin and pyroxasulfone at preemergence application and reduced concentration in the soil when compared with no-till, mainly at 0 DAT. Main differences in herbicide concentration were observed between no-till and cereal rye treatments rather than cereal rye termination times. Despite reducing herbicide concentration in the soil, the presence of the cereal rye biomass did not affect early-season residual Amaranthus spp. control. The adoption of effective preemergence herbicides associated with a properly managed cereal rye cover crop is an effective option for integrated Amaranthus spp. management programs in soybean production systems.

Effect of Weed Management Practices on Growth, Yield of Vegetable Cowpea (Vigna unguiculata (L.) Walp.) cv. Kashi Kanchan

The present investigation contains seven different treatments viz., weedy check (control), weed free check (3 hand weeding) (first hand weeding at 25 DAS), pre-emergence application of Pendimethalin @ 6ml/L, pre-emergence application of Pendimethalin @ 6ml/L + one hand weeding, pre- emergence application of Pendimethalin @ 6ml/L + post emergence @ 40-50 g/ha at 25 DAS, post-emergence application of Metribuzin @ 525g/ha at 25DAS and post-emergence spray of Imazethapyr @ 100 g ai/ha at 25 DAS replicated thrice. The cowpea variety ‘Kashi Kanchan’ was used in experiment. Results of the experiment revealed that though, the weed free check (T2) recorded zero weed population and slightly higher values of growth and yield parameters but among tested treatments, pre-emergence application of Pendimethalin @ 6ml/L + one hand weeding (T4) and pre-emergence application of Pendimethalin @ 6ml/L + Quizalofop ethyl @ 40-50 g/ha at 25 DAS(T5) significantly reduced weed number (48.12 and 52.18/m2) and produced significantly highest plant height (47.30 and 45.98 cm), pod length (21.64 and 20.86 cm), number of pods/plant (35.94 and 34.18), average pod weight(11.18 and 11.06 g), green pod weight/plant (367.84 and 348.63g), green pod weight/plot (11.24 and 10.54 kg) and green pod yield per hectare(118.96 and 111.55q). However, these three treatments (T2, T4 and T5) were statistically at par with each other in terms of growth and yield parameters.Hence, these two weed management practices (T4 and T5) may serve as alternative of manual weeding and may be recommended for farmers of the central plain zone of Uttar Pradesh for higher returns from vegetable cowpea crop.

Herbicidal Management of Cuscuta spp. in Berseem (Trifolium alexandrinum L.) Crop

Aims: To correlate the efficiency of herbicides towards control of Dodder (Cuscuta spp.) in green forage and seed yield of berseem crop.
 Study Design: Randomized block design (RBD).
 Place and Duration of Study: Research cum Instructional Farm, Indira Gandhi Krishi Vishwavidyalaya, Raipur (C.G.) during the Rabi season of 2019-20.
 Methodology: The experiment consisted of three replications and ten treatments, in which oxyfluorfen was applied as pre-emergence herbicide and pendimethain was applied as pre-emergence and early post-emegence herbicide while imazethepyr, imazamox 35 % + imazethapyr 35 % (ready mix) and sodium acifluorfen 16.5 % + clodinafop-propargyl 8 % (ready mix) were applied as post-emergence herbicides in different proportion along with control.
 Results: No cuscuta infestation was observed during the experimentation period under any treatments (T1, T2, T3). Highest cuscuta length (41.20 cm), threads (3.00/m2), and dry weight (0.49 g/m2) were recorded just before 1st cutting with treatment (T7). Just before 2nd cutting, the highest cuscuta length (46.32 cm), threads (4.00/m2), and dry weight (0.74 g/m2) were recorded with treatment (T5) and before 3rd cutting, the highest cuscuta length (53.11 cm), threads (5.00/m2), and dry weight (1.06 g/m2) recorded under control (T10). No cuscuta infestation after herbicide application in all treatments. The significantly highest total green forage and seed yield of 60.12 ton/ha and 0.35 ton/ha were recorded under the pre-emergence application of oxyfluorfen 250 g/ha (T3) as compared to the rest of the treatments.
 Conclusion: The selective action of oxyflourfen, pendimethalin, and imazethapyr on berseem and non-selective control of weeds, including cuscuta spp., resulted in minimal weed competition during critical growth stages. This created a favourable environment for berseem, leading to improved growth, yield quality, and overall crop productivity. The effective herbicidal treatments played a vital role in enhancing berseem yield.

Sensitivity of weeds to herbicide Lumax and its effectiveness in grain maize crops

Sensitivity of weeds to Lumax herbicide under growing conditions with pre- and post-emergent application was studied. Evaluation of biological and economic efficiency of Lumax herbicide at different terms of use was given. The studies were conducted in 2020–2022 in the Primorsky Territory. The soil of the experimental plots is meadow-brown podzolized, containing 3–4% of humus in the arable horizon. The agricultural technique is based on no-tillage technology. The forecrop was soybeans. The hybrid population P 8521 was used in the field experiments. The sensitivity of 16 weed species was studied when used in pre-emergence applications and 18 when used on vegetative plants in the early stages of their development. Visual observations of plant development after treatments with Lumax herbicide were made. At soil application, the preparation inhibited the germination of lamb’s-quarters, pigweed, hemp nettle, barnyard grass, bur beggar-ticks, yellow-foxtail grass and green bristle grass, field milk thistle and yellow thistle. Sprouts of China jute, common persicaria and copper leaf were completely dead by the 7th day. Moderate sensitivity was shown by ragweed, hairy cupgrass, and dayflower. Trailing hollyhock proved to be resistant to this herbicide. When using Lumax on vegetating plants, 17 species were highly sensitive, with only hairy cupgrass being relatively sensitive. In field experiments in the grain maize crop, weed infestation averaged 531 plants/m2 with a total above ground mass of 3279 g/m2. The herbicide was applied at three times: before sprouting, in the phases of the 2-3rd and 5th-6th of corn leaves. There were advantages and disadvantages with each term of its use. At preemergence, it more actively suppressed annual grasses, while at late (the 5th-6th leaf phase) it suppressed perennial dicotyledons. Application of the herbicide in the 2nd-3rd corn leaf phase showed approximately equal effect on the weeds. Lumax effectively eliminated dayflower and annual dicotyledonous weeds. Regardless of the timing of application, it contributed to saving 29.8-36.7 co of corn grain/ha.

Effect of Weed Management Practices on Growth, Yield and Quality of Okra [Abelmoschus esculentus (L.) Moench

The present investigation entitled “Effect of weed management practices on growth, yield and quality of okra Abelmoschus esculentus (L.) Moench)” was conducted at Vegetable Research Farm, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur during kharif season 2022. The experiment was laid out in Randomized Block Design with seven different treatments viz. T1 = Pre-emergence application of Pendimethalin @ 6 ml /L, T2= Post emergence application of Quizalofop-ethyl @ 0.040 kg/ha ,T3 = Pre-emergence application of pendimethalin @ 6 ml/L + one hand weeding at 40 DAS , T4 = Post emergence application of Quizalofop-ethyl @ 0.040 kg ha-1 at 25 DAS + one hand weeding , T5 = Pendimethalin @ 6 ml /L as pre-emergence + Quizalofop-ethyl @ 0.040 kg ha-1 at 25 DAS , T6 = Weed free check (Three hand weeding) 20, 40 and 60 DAS , T7 = weed check control replicated thrice. The result of the study revealed that at 30 DAS maximum plant height (30.96cm) was reported in treatment T3 : Pre-emergence application of Pendimethalin @ 6 ml/L + one hand weeding at 40 days of sowing whereas at 60 and 90 DAS maximum plant height (75.50 and 113.53 cm) was reported in T6 : Weed free check (Three hand weeding) 20, 40 and 60 DAS. Maximum number of branches per plant (4.60)at 60 DAS was found in T3 : Pre-emergence application of Pendimethalin @ 6 ml/L + one hand weeding at 40 DAS and 90 DAS maximum number of branches per plant (5.86) was reported in T6 : Weed free check (Three hand weeding) 20, 40 and 60 DAS. Maximum number of nodes (17.83 ) at 60 days after sowing was noticed in treatment T3 = Pre-emergence application of Pendimethalin @ 6 ml/L + one hand weeding at 40 DAS and 90 Days after of sowing maximum number of nodes () was in treatment T6 = Weed free check (Three hand weeding) 20, 40 and 60 DAS. Maximum Pod diameter( 1.74cm) , fruit weight (12.88gm ), pod length( 14.1cm) , number of pods per plant( 25.66 ) , pod yield per plant ( 304.73gm) , pod yield per hectare (16.91 t), TSS( 3.2 Brix), crude fibre (8.46%) and cholorophyll content (1.18 mg) and relative cholorophyll content (54.39) .

Effect of Different Weed Management Practices on Growth and Yield of Cabbage (Brassica oleracea var. capitata L.)

As cabbage is cultivated with wide spacing, it is prone to profuse weed infestations, resulting in reduced crop yields and subsequent significant economic losses. A field experiment comparing different weed management treatments namely T1 (two hand weedings), T2 (paddy straw mulch), T3 (pre-emergent application of oxyfluorfen @ 1 kg a.i./ha), T4 (PE application of pendimethalin @ 1.5 kg a.i./ha), T5 (PE application of pendimethalin @ 1 kg a.i./ha + HW at 35 days after transplanting), T6 (PE application of oxyfluorfen @ 1 kg a.i./ha + HW at 35 DAT), T7 (weed-free) and T8 (weedy check) was conducted to evaluate their efficacy on growth, yield and economics of cabbage (Brassica oleracea var. capitata L.). The results revealed that the maximum value of plant height, number of unwrapped leaves, fresh weight of heads, dry weight of wrapped leaves and yield per hectare was obtained in plots under treatment T7 (weed free). Similarly, in terms of weed parameters minimum weed count, weed dry weight, weed index and maximum weed control efficiency were observed in treatment T7 (weed free). Maximum net return and benefit: cost ratio was observed under the treatment T5 (PE application of pendimethalin @ 1 kg a.i./ha + one HW at 35 DAT), making it an economically practical option for controlling weeds in cabbage.