Weed Infestation Research Articles

Development of an HPPD-Inhibitor Resistant Wheat and Multiomics Integrative Analysis of Herbicide Toxicity and OsHIS1 Detoxification in Wheat.

Weed infestation in agricultural fields significantly diminishes crop yields. Herbicides are widely used as a primary method of weed control. Developing herbicide-resistant crops through the expression of resistant genes represents a sustainable approach. This study generated wheat germplasms highly resistant to 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicides by transforming the rice HPPD INHIBITOR SENSITIVE 1 (OsHIS1) gene into Xinong 511, conferring resistance to mesotrione at levels up to nine times the typical field application rate (1350 g ai ha-1). Agronomic trait evaluations under greenhouse and field conditions showed no additional effects on wheat. Herbicide susceptibility assays confirmed the specific resistance to different HPPD inhibitors. Transcriptome and metabolome analyses revealed regulation of flavonoid and photosynthesis-antenna protein pathways in the herbicide functional. Collectively, OsHIS1 could be applied in the production of herbicide-resistant wheat.

Effect of Nano Encapsulated Pendimethalin on Growth Attributes of Rice

Weed infestation is a major problem in upland rice of Kerala. Pendimethalin is a selective pre-emergent herbicide used to control broad-leaved and grassy weeds in rice fields. However, herbicides like pendimethalin often face losses in the agroecosystem through various pathways, reducing their effectiveness and potentially contaminating the environment, including groundwater. Encapsulation of herbicides is an innovative method designed to enhance their efficacy while minimizing environmental contamination, making herbicide application more efficient for weed control. A field experiment was carried out at the Instructional Farm, College of Agriculture, Vellayani, Kerala, India to evaluate the effect of different concentrations of Nano Encapsulated Pendimethalin (NEP) for weed management in upland rice. Synthesis of nano encapsulated pendimethalin was done at Department of Agronomy, College of Agriculture, Vellayani. The study revealed that nano encapsulated pendimethalin had significant influence on growth attributes over normal commercial formulations. Among all the growth parameters Nano Encapsulated Pendimethalin (NEP) with 4% starch aqueous phase at 1.0 kg ha-1 showed comparable result with hand weeding at 15 and 30 Days After Sowing (DAS). The nano encapsulated formulation had a particle size of 486.6 nm and zeta potential of -18 mV.

Effect of Changing Temperature and CO2 Concentration on Weed Dynamics and Behaviour: A Review

Agriculture and climate change are interwoven with each other in various measures, as climate change is the main culprit of biotic and abiotic stresses, which has adverse impact on crops and weed flora and the effectiveness of weed management strategies. Indeed weed physiology and crop productivity has been greatly influenced by several means of climate variability. Climate change causes a shift in weed population dynamics by altering the physiological pathways with the changing temperature and CO2 conditions. Climate change can affect crop-weed interactions by favouring C4 weeds in increased temperature scenarios requiring adaptation and mitigation strategies. Weeds can also shift their range by invading into new areas and higher latitudes or altitudes due to climatic variability affecting weed diversity, establishment, and management. These factors helps in understanding the crop interactions, weed infestation and herbicide efficacy. This review paper summarizes the challenges that occur due to climate change in weed behaviour requiring more attention on sustainable agricultural production.

Effects of Green Manure Cover Crops on Weed Suppression at Mashare and Liselo, Namibia

Small-scale farming communities in northern Namibia often encounter poor soil fertility and financial constraints. They don’t afford buying mineral fertilizers and herbicides, thus highlighting the need for cost-effective cropping systems that enhance productivity. While green manure cover crops (GMCCs) have been extensively studied elsewhere and shown to boost productivity, information on their use remains limited in Namibia. Experiments were conducted over two seasons (2016/2017-2017/2018) at Mashare Irrigation Training Center (MITC) and Liselo Research Station (LRS), which have different soil types, to explore the effects of rotating Pearl millet and maize with various GMCCs on crop weed populations. The experiments compared the effects of rotating nine different GMCCs with Pearl millet and maize separately against monocropping of Pearl millet and maize. Results showed that weed density varied across treatments and locations, with the highest densities observed in certain rotations, such as Pearl millet-pigeon pea and maize-pigeon pea, while the lowest densities were found in rotations involving lablab and velvet bean. This is indicative that lablab and velvet bean suppressed weeds better than all other GMCCs, while pigeon pea was vulnerable to weed infestation. Lablab exhibited the highest biomass yields. Overall, rotating Pearl millet and maize with cover crops demonstrated greater benefits compared to monocropping, emphasizing the need to identify suitable cover crops for specific niches to optimize productivity.

Environmental Impact and Decompsition of Polycyclic Aromatic Hydrocarbons (PAHs) in Urban Soils: Challenges and Future Directions

The rapid pace of urbanization and development has led to an increasing global concern over polycyclic aromatic hydrocarbons (PAHs) due to their persistent and widespread presence in the environment, posing significant threats to ecosystems and human health. PAHs originate from both natural and human-made sources and can be categorized based on their origin into pyrogenic, petrogenic, and biogenic products. Upon entering the environment, PAHs undergo various chemical and biological transformations, and their movement occurs through processes such as air-to-soil and soil-to-air transport. Composting, a green and cost-effective technology, offers a promising solution for PAH remediation. This process, which includes mesophilic, thermophilic, cooling, and maturing stages, can yield compost that is useful as fertilizer and soil amendment in agriculture. The success of composting depends on factors such as substrate bioavailability, oxygen levels, nutrient supply, and environmental conditions. While composting has shown effectiveness in reducing PAH levels, it is not without challenges, including the risk of weed infestation, greenhouse gas emissions, and odor pollution. The main obstacles in PAH remediation today are the limited bioaccessibility of PAHs and the insufficient focus on the formation of oxygenated PAHs during the process. Future research should address these challenges, particularly by improving PAH bioaccessibility and mitigating issues related to odor and greenhouse gas emissions.

Presumption of Herbicide Resistant Weeds and Yield of Boro Rice as Influenced by Pre- and Post-emergence Herbicides

In Bangladesh, weed infestation is a leading problem in rice cultivation and the sole dependency on post-emergence herbicides is ineffective. Therefore, a field experiment was carried out at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from December 2021 to May 2022. The study was done to determine the relative effectiveness of different pre-emergence herbicides and to presume the herbicide-resistant weeds and yield of boro rice as influenced by pre-and post-emergence herbicides. Four rice varieties: BAU dhan3 (V1), BRRI dhan28 (V2), BRRI dhan81 (V3), BRRI dhan96 (V4) and six herbicide managements: Control (H1), Hand Weeding at 30 DAT (H2), Bensulfuron methyl @ 980 g ha-1 (H3), Pretilachlor @ 2 L ha-1 (H4), Carfentrazon ethyl @ 208 mL ha-1 (H5), Ethoxisulfuron @ 200 g ha-1 (H6) were used in a randomized complete block design (RCBD) with three replications. The most dominant weed species in the experimental plots were Echinochloa crussgalli, Scirpus mucronatus, Monochoria hastata, Enhydra fluctuans and Oxalis europaea. This study found Ethoxisulfuron (H6) and Carfentrazon ethyl (H5) were the most effective weed management treatments for weed suppression and grain yield at twice the recommended doses. In this study, the highest grain yield (5.40 t ha-1), straw yield (6.80 t ha-1) and biological yield (12.20 t ha-1) were obtained from BRRI dhan81 (V3) with hand weeding (H2) and highest harvest index (45.60%) were obtained from BAU dhan3 (V1) with Pretilachlor (H4). Therefore, this result is useful for farmers at field level cultivation of boro rice.

Sole and sequential application of herbicides and botanicals for weed management in summer sesame

Weed infestation poses a significant challenge in sesame cultivation, leading to yield losses and decreased economic returns for farmers. The present study comprehensively analyses various weed control approaches, including allelopathic interaction with integrating herbicides and hand-weeding practices. The experiment was conducted at the Agriculture Farm, SOA, Odisha, during the summer of 2023 with 10 weed management treatments in RBD with 3 replications. The objective was to study different weed management practices, including the sole and sequential application of herbicides and botanicals, to control diverse weeds and enhance summer sesame growth, yield and profitability. The dominance of Digitaria sanguinalis (L.) Scop., Echinochloa colona (L.) Link. and Poa annua L. among grassy weeds and Melochia corchorifolia L., Cleome viscosa L. and Cassia tora L. among the broadleaved weeds were evident in summer sesame. The execution of different treatments showed that integrated use of aqueous leaf extract of Parthenium hysterophorus at 5 % concentration, followed by quizalofop-p-ethyl at 50 g/ha, was found on par with hand-weeding and brought down the weed count and biomass, which in turn increased the growth of summer sesame. The maximum yield of (793 kg seed/ha and 3035 kg stalk/ha) was registered under twice hand weeding. It was comparable with the spraying of aqueous leaf extract of Parthenium hysterophorus at 5 % concentration followed by (fb) quizalofop-p-ethyl at 50 g/ha (772 kg seed/ ha and 2968 kg stalk/ha). Economic analysis of sesame revealed that the maximum return (Rs. 37454/- per ha) and return/rupee (2.28) were recorded with aqueous leaf extract of P. hysterophorus at 5 % concentration fb quizalofop-p-ethyl at 50 g/ha treatment.

Effect of Different Weed Management Practices on growth and yield in Potato at Khumaltar, Lalitpur, Nepal

Potato (Solanum tuberosum L.) is the fifth most important crops in the world in terms of production with an estimate of 375 million metric tons. In Nepal, potato ranks second in terms of production and sixth in terms of area coverage. Potato production is affected by weed infestation. Weeds compete with crops for nutrients, water and other resources, which eventually reduce the crop yield. The critical period of crop-weed competition for potato is 25-40 days from planting depending on the climatic-zone and planting seasons. The most common method of weed control in Nepal is manual method, while herbicides are uses in less areas. Weeds are considered as the major problem in conventional and organic farming, due to lower yields by weeds and higher costs of labor for weed control. Mulching is one of the best and safest practice for effective weed management in potato due to which micro-climate manipulation is developed. Metribuzin is widely used herbicides in potato that controls a range of broadleaf weed species and suppresses many grassy weeds. To study the performance of different weed management practices in potato ten treatments were set up viz., three herbicides (pendimethalin@ 1.0 kg a.i ha-1, metribuzin@ 0.5 kg a.i ha-1 and atrazine @ 0.25 kg a.i ha-1) constituting seven treatments, one mulching with rice straw, one treatment with two manual hoeing, and another treatment with no any weed management practices as control.The treatments were laid out in RCB design with 4 replications. The potato variety Janak Dev was planted on 12th Feb 2021 and 23rd Jan 2022 with tuber rate of 4.1 t.ha-1 with row spacing of 60 cm and plant to plant 20 cm in a plot size of 4 x 3 meter in flat bed. Growth parameters such as plant height, plant fresh and dry biomass were recorded. Data on weed density, weed dry biomass, and tuber yield were taken.The economics of the different treatments were calculated. Among the treatments metribuzin@ 0.25 kg a.i ha-1 as pre-emergence proved effective in controlling weeds showing highest weed control efficiency (200.7 %) and tuber yield (32.79 t ha-1) . However, the treatment rice straw mulch @ 6 t ha-1 produced the highest tuber yield (38.31 t ha-1), 73.4 % increased yield over control, weed control efficiency(147.1%), economic benefit (NRS 13,40,850), benefit cost ratio (4.93).The treatment rice straw mulch @ 6 t ha-1 showed superiority among the different weeds management practices.

Weed community differences in row crops with varying input levels in Ghana

Abstract Peanut (Arachis hypogaea L.) and maize (Zea mays L.) are essential crops for Ghana’s economy and food security, but weed infestation poses a significant threat to their cultivation. Crop rotations influence weed communities, but little is known about these processes in peanut-cropping systems in West Africa. This study investigated the impact of different crop rotations and input levels on weed communities in Ghana over 3 yr. Results showed that low inputs (absence of herbicide and fertilization) favored species richness, while higher input levels (weed control with herbicides and fertilizer use) reduced it. Diversity and evenness were also affected by inputs, with varying patterns across locations and seasons. Weed population growth rates (λ) varied significantly by location and treatment; all management programs resulted in increasing weed populations. Principal component analysis revealed distinct associations between weed species and crop management. The majority of weed species exhibited a generalist behavior and did not associate with a particular management. However, billygoat weed (Ageratum conyzoides L.) and Benghal dayflower (Commelina benghalensis L.) were positively associated with high-input systems, while purple nutsedge (Cyperus rotundus L.) exhibited strong associations with low and medium inputs. The weed–crop rotation dynamics described here demonstrate how management drives the selection of weed species that are more pervasive and interfere with important food crops in Ghanaian agriculture.

Effects of Metribuzin on Soil Microbiome and Weed Management Under Varying Planting Practices and Potato Seed Dormancy

AbstractWeed infestation in potato field has become a major concern to smallholder farmers and environment, requiring sustainable intervention. This study aimed to determine (i) whether metribuzin application rate (0, 0.5, 1 (standard), 1.5, and 2 kg ai ha−1) has effects on soil microbes and soil nutrients in the short term using potted soil and (ii) the influence of potato seed dormancy (short; Shangi variety and long; Unica variety) and planting technique (surface, ridge, or furrow planting) on the efficacy of weed management practice (metribuzin (480 g L−1) herbicide and hoeing) in the field. Bacterial colony counts were recorded upon isolation from the potted soil. Soil nutrients were also analysed before and after metribuzin treatment. Data on crop growth (height and stem count), weed abundance, yield, costs, and revenues were recorded from a field experiment. Morphologically distinct bacterial strains were tested for Gram reaction and response to carbon utilization using analytical profile index kits (API 50 CH and 20 NE). In total, nine distinct bacterial strains were isolated and all were Gram positive, with variation in response to carbon substrates. Concentration of 2.0 kg a.i ha−1 significantly (p ≤ 0.05) reduced bacterial count in the first day, followed by an increase in the subsequent incubation days, while 1.0 and 1.5 kg a.i ha−1 concentrations had the highest colony development index and species richness. Significant effects of metribuzin on soil pH, total N, and total organic C in the short term were revealed. Notably, weedy plots had the highest Shannon weed index. Weeds reduced stem count and height growth by 57% and 62% respectively. Plots with Shangi had 9.8% lower weed count than those with Unica and hence higher yield was recorded from the former. While surface planting had the lowest weed control efficacy, crop growth attributes, and yield, furrow and ridge planting were not significantly different. Weed abundance and crop growth attributes in metribuzin and hand-hoed plots did not differ significantly, yet hoeing resulted in 5.30 t ha−1 above that obtained from plots managed using metribuzin. Higher dry matter and tuber yield were observed from hoed plots with Shangi planted in furrow or ridge. Use of metribuzin resulted in higher net benefit ratio and marginal rate of return than hand hoeing. The results reveal that use of metribuzin early and later in the potato growing phase can minimize weed infestation, but the efficacy depends on planting method and seed dormancy.

Laser Weeding Technology in Cropping Systems: A Comprehensive Review

Weed infestations pose significant challenges to global crop production, demanding effective and sustainable weed control methods. Traditional approaches, such as chemical herbicides, mechanical tillage, and plastic mulches, are not only associated with environmental concerns but also face challenges like herbicide resistance, soil health, erosion, moisture content, and organic matter depletion. Thermal methods like flaming, streaming, and hot foam distribution are emerging weed control technologies along with directed energy systems of electrical and laser weeding. This paper conducts a comprehensive review of laser weeding technology, comparing it with conventional methods and highlighting its potential environmental benefits. Laser weeding, known for its precision and targeted energy delivery, emerges as a promising alternative to conventional control methods. This review explores various laser weeding platforms, discussing their features, applications, and limitations, with a focus on critical areas for improvement, including dwell time reduction, automated navigation, energy efficiency, affordability, and safety standards. Comparative analyses underscore the advantages of laser weeding, such as reduced environmental impact, minimized soil disturbance, and the potential for sustainable agriculture. This paper concludes by outlining key areas for future research and development to enhance the effectiveness, accessibility, and affordability of laser weeding technology. In summary, laser weeding presents a transformative solution for weed control, aligning with the principles of sustainable and environmentally conscious agriculture, and addressing the limitations of traditional methods.

Weed management options in drum seeded wetland rice

High labour requirement and cost for raising nursery and transplanting of the seedlings has necessitated the shift from transplanted rice to direct-seeded rice. To reduce the requirement of large quantity of seeds, incidence of pests and diseases in broadcasting and to ensure uniform seed distribution for consistent crop growth and easier maintenance, mechanization is needed in direct-seeded rice. The major constraint experienced in wet DSR is the occurrence of high weed infestation as emerging seedlings in direct-sown fields are less competitive with concurrently emerging weeds. An experiment was conducted at M. S. Swaminathan Rice Research Station, Moncompu, Kerala Agricultural University during kharif and rabi 2021-22, with eight treatments and three replications in randomised complete block design to identify suitable cost-effective agronomic management practices to enhance the productivity of drum seeded rice and to maximise its resource-use-efficiency. The results revealed wet DSR using drumseeder as a viable crop establishment method for reducing the seed requirement, cultivation time, energy, cost of cultivation, pest and disease infestation, minimise plant stress due to transplanting and sustaining yield. There was significant variation in the yield and yield attributes in drum seeding depending on the weed management strategies adopted viz., two conoweedings, post emergent herbicide application, pre followed by post emergent herbicide application, post emergent herbicide application followed by conoweeding. Post-emergence application of Chlorimuron ethyl + Metsulfuron methyl @ 0.004 kg/ha and Penoxsulam + Cyhalofop butyl @ 0.135 kg/ha as tank mix at 18 DAS followed by conoweeding at 30 DAS was found economical in drum seeding which was on par yield with broadcasted crop yield under post emergent herbicide application.

ИЗУЧЕНИЕ ВЗАИМОСВЯЗЕЙ МЕЖДУ ГЛУБИНОЙ, СПОСОБАМИ ОБРАБОТКИ ПОЧВЫ И УРОЖАЙНОСТЬЮ КАРТОФЕЛЯ В ГОРНОЙ ЗОНЕ РСО-АЛАНИЯ

Depth and methods of soil cultivation for potatoes are among the most important agrotechnical techniques that allow increasing the yield of tubers without significant additional costs. The studies were conducted from 2020 to 2023, in the mountain-meadow subalpine zone in the Dargavs basin of the Republic of North Ossetia-Alania at an altitude of 1450 m above sea level (Dargavs village). The soil of the experimental site belongs to the mountain-meadow subalpine leached with a humus-illuvial horizon loamy on the eluvium of clay shale. Meteorological conditions during the years of the studies were noted as contrasting. Temperature conditions in the spring were relatively favorable, but during the flowering phase a decrease in air humidity and an increase in air and soil temperature were noted. Potatoes of the Farn variety were planted in the first ten days of May, harvested in the second ten days of September. Moldboard-less tillage methods do not significantly affect soil moisture, accumulation of available nutrients, crop yield and its quality compared to moldboard ones, but weed infestation increases. Plowing of mountain chernozems of the Republic of North Ossetia-Alania should be carried out to a depth of no more than 25 cm. Increasing the plowing depth to 35 cm or decreasing it to 15 cm causes a decrease in crop yield (subsoil tillage). Economic efficiency with moldboard plowing to a depth of 25 cm: profit from sales per 1 ha amounted to 283.1 thousand rubles. Increasing the plowing depth to 35 cm reduced profit to 56.1 thousand rubles, and decreasing it to 15 cm to 52.2 thousand rubles. The level of economic profitability amounted to 141.4; 165.7 and 147.2 %, respectively. When applying fertilizers at a dose of N60P60K60 and cultivating the soil with a flat cutter to a depth of 25 cm, the profit amounted to 247.1 thousand rubles per 1 ha with an economic profitability of 152.2 %.

An overview of the role of nanoherbicides in tackling challenges of weed management in wheat: A novel approach

Abstract One of the most significant biotic constraints that wheat production faces is weed infestation. Wheat is infested with different weeds that cause yield losses (up to 100%) that vary based on the type of weed, their density, and the environmental conditions. Chemical weed control is the most common method to control weeds in wheat. However, widespread herbicide resistance (>365 cases worldwide) has challenged the sustainability of this method. Use of nanoherbicides is a promising strategy to cope with the issue of herbicide resistance. To achieve weed control conditions during the whole growing season, nanoformulations of herbicides are a delivery strategy that involves covering an active component with various materials that vary in size from nano to nanoscale and then releasing the substance in a controlled manner. Nanoherbicides prevent leaching and volatilization of active components and premature degradation through photolysis, hydrolysis, and biodegradation. According to studies, nanoencapsulation of herbicides produces more targeted and less hazardous agricultural formulations. Using nanoherbicides in lower concentrations is beneficial. It lessens the long-term impacts of herbicide residues in wheat fields and the toxicity of these herbicides to the environment. It is also beneficial in eliminating the weeds without ever interacting with the crop plants, which eventually results in a greater wheat yield. This review provides a comprehensive overview of the emerging field of utilizing nanoparticles (NPs) in herbicides for effective weed management in wheat crops. This article explores the novel approach of integrating NPs with herbicidal agents, highlighting their potential benefits and challenges. The review also addresses the current state of research, recent advancements, and potential future directions in this evolving area of agricultural science.

Harnessing UAVs and deep learning for accurate grass weed detection in wheat fields: a study on biomass and yield implications

Weeds are undesired plants competing with crops for light, nutrients, and water, negatively impacting crop growth. Identifying weeds in wheat fields accurately is important for precise pesticide spraying and targeted weed control. Grass weeds in their early growth stages look very similar to wheat seedlings, making them difficult to identify. In this study, we focused on wheat fields with varying levels of grass weed infestation and used unmanned aerial vehicles (UAVs) to obtain images. By utilizing deep learning algorithms and spectral analysis technology, the weeds were identified and extracted accurately from wheat fields. Our results showed that the precision of weed detection in scattered wheat fields was 91.27% and 87.51% in drilled wheat fields. Compared to areas without weeds, the increase in weed density led to a decrease in wheat biomass, with the maximum biomass decreasing by 71%. The effect of weed density on yield was similar, with the maximum yield decreasing by 4320 kg·ha− 1, a drop of 60%. In this study, a method for monitoring weed occurrence in wheat fields was established, and the effects of weeds on wheat growth in different growth periods and weed densities were studied by accurately extracting weeds from wheat fields. The results can provide a reference for weed control and hazard assessment research.

Geographical Distribution and Abundance of Species of the Pycreus Genus in Rice Production Regions in Rio Grande do Sul

Theoretical Reference: Identifying, tracking, and analyzing weed infestation levels in rice crops are essential for developing more effective control strategies, ultimately enhancing efficiency, reducing costs, and minimizing environmental impact. This study focuses on the geographic distribution and abundance of species within the Pycreus genus (family Cyperaceae) in rice fields in Rio Grande do Sul (RS), Brazil. Method: During the 2005/06 growing season, collections and abundance assessments of Pycreus species were conducted across three irrigated rice fields located in three municipalities within five major rice production regions of RS. Plants were collected during vegetative or reproductive stages, dried, and identified using specialized literature. Specimens were then deposited as vouchers in the PEL Herbarium at the Department of Botany, Federal University of Pelotas. Results and Conclusion: The study revealed the presence of Pycreus species in rice fields across RS, with P. polystachyos (Rottb.) P. Beauv. being the most abundant and frequently observed species. P. macrostachyos (Lam.) J. Raynal and P. lanceolatus (Poir.) C.B. Clarke were also identified, though less commonly. The highest abundance of Pycreus species was recorded in the coastal physiographic region, particularly within the Internal Coastal Plain of Lagoa dos Patos and southern rice production areas. Implications of Research: These findings emphasize the need for targeted weed management strategies in rice cultivation, particularly in regions where Pycreus species are most prevalent, to enhance crop productivity and sustainability. Originality/Value: This study provides valuable insights into the distribution and abundance of Pycreus species in RS rice fields, contributing to the understanding of weed dynamics in rice production and offering a basis for the development of more effective control measures.

The Response of Insects and Weeds within the Crop to Variation in Sowing Density of Canola

The relationships between weeds and insects in canola stands with different seeding rates are not fully understood. Varying seeding rates in canola crops can create different conditions that affect both weed and insect populations and their interactions. The aim of this work was to determine the response of weeds and insects of selected taxa to different densities of canola stand densities and to clarify the interactions between weeds and insects in canola stands. The field experiment was conducted on a plot located in the cadastral area of the municipality of Pěnčín (Moravia, Czech Republic). The results show that a reduced canola sowing rate of oilseed rape leads to increased weed infestation, which is dominated by one taxon (Papaver rhoeas L.). The increase in weed infestation of canola stands is not reflected in an increase in the diversity of captured insects. Increased canola seeding rate improves weed suppression but increases the number of canola pest insects. A higher number of plants and more canola biomass increase the food supply and, thus, make the stand more attractive to canola pests. The taxon Brassicogethes aeneus dominated the pests species spectrum. Changing the seeding rate of canola results in a response in weed and insect populations. The standard recommended seeding rate is optimal in terms of competitive suppression of weeds and the occurrence of pests and trapped insects. Increasing or decreasing the seeding rate of rapeseed does not bring any benefits in terms of pest regulation or biodiversity. However, the results obtained indicate an interesting weed–insect interaction in the conditions of canola stands.

Intercomparison of Different Agrochemicals (Herbicides) and Manual Methods of Weed Control on Weed Population and Weed Control Efficiency in Wheat (Triticum aestivum L.) Crop in Himachal Pradesh Dist

Aims: A research study entitled Intercomparison of different Agrochemicals (Herbicides) and manual methods of weed control on weed population and weed control efficiency in wheat crop (Triticum aestivum L.) in Himachal Pradesh district Mandi. Study Design: The experiment was designed using a Randomized Block design method. Place and Duration of Study: Department of agronomy, School of Agriculture, Abhilashi university, Chail Chowk, Mandi, (H.P.) during the Rabi season of 2022-23. Methodology: The field trail was conducted with eight treatments and replicated thrice. The investigation included eight different weed control techniques i.e. T1 -weedy check, T2 - weed free, T3 - hand weeding at 30 DAS, T4 - 2, 4-D @ 0.5 kg a.i. ha-1 + Sulfosulfuron @ 0.02 kg a.i. ha-1 at 30 DAS,T5 - Pendimethalin @ 1.5 kg a.i. ha-1(P.E) + Quizalofop-ethyl @ 50 gm a.i ha-1 (PoE at 25 DAS) + one hand weeding, T6 - 2, 4-D @ 0.5 kg a.i. ha-1, T7 - 2, 4-D @ 0.5 kg a.i. ha-1 + one hand weeding at 30 DAS, T8 - 2, 4-D @ 0.5 kg a.i. ha-1 + two hand weeding at 30 and 45 DAS. Results: The investigation found that the most effective ways to control weeds are by keeping the area completely weed free by using pendimethalin @ 1.5 kg a.i. ha-1(P.E) + Quizalofop-ethyl @ 50 gm a.i ha-1(PoE at 25 DAS) + one Hand weeding (Treatment T2) was found the most successful in terms of achieving the lowest weed density and highest weed control efficiency. Application of pendimethalin @ 1.5 kg a.i. ha-1(P.E) + Quizalofop-ethyl @ 50 gm a.i ha-1 (PoE at 25 DAS) + one hand weeding was found to be better than using herbicides to reduce weed infestation in wheat crops. Conclusion: Based on the results, it can be concluded that integrated weed management practices weed-free treatment was the most effective option for managing weeds in wheat.

Effects of occasional tillage on soil physical and chemical properties and weed infestation in a 10-year no-till system

Few studies have investigated how one-time targeted tillage of long-term no-till fields impacts topsoil properties and weed dynamics. An on-farm trial was implemented in 2020 to test the effects of occasional tillage (OT) in Morocco with a long-term no-tillage (NT) system and rainfed field crops: durum wheat (Triticum durum), faba bean (Vicia faba minor), and chickpea (Cicer arietinum). Four treatments were established, namely, continuous NT with crop residues maintained (“NT + residue”); continuous NT with crop residues not maintained (“NT-residue”); shallow inversion tillage (“shallow OT”); and deep non-inversion tillage (“deep OT”). We assessed the effect of these treatments on soil physical and chemical properties in 0–10 and 10–20 cm soil depths after crop harvest of the 2020–2021 (year 1) and 2021–2022 (year 2) growing seasons corresponding to 1 and 2 years after OT, respectively. In addition, we evaluated the effect of the treatments on weed populations and the effect of the legume crop rotated with wheat on soil nitrogen (N) and weed density. In year 1, deep OT reduced the water content at field capacity and available water capacity at 0–10 cm compared to continuous NT; the cation-exchange capacity (CEC) under deep OT was lower than in NT-residue and NT + residue at 0–10 cm and 10–20 cm, respectively. Furthermore, deep OT increased ammonium-N (NH4-N) at 0–10 and 10–20 cm compared to NT + residue but reduced exchangeable potassium (K) at 10–20 cm depth compared to NT-residue. In year 2, shallow OT had lower total porosity at 10–20 cm than NT + residue, while shallow and deep OT recorded higher water-stable aggregates at 0–10 cm than NT + residue; at 10–20 cm, deep OT recorded lower CEC than NT + residue. However, deep OT had higher nitrate-N (NO3-N) and available sulfur (S) than NT-residue at 10–20 cm. Occasional tillage did not significantly affect 10 out of 19 of the soil properties evaluated, including soil organic matter (SOM), in all the years and did not help reduce the stratification of soil nutrients in NT. In year 1, 50 days after OT, deep OT reduced the weed density by 46% compared to NT + residue, while in year 2, 406 days after OT, shallow OT reduced weed density by 53% compared to NT-residue. Regarding the effect of the legume rotated with wheat, faba bean appeared to be the better preceding or following wheat crop as it resulted in higher residual soil mineral N and lower weed infestation than chickpea.

Bacterial allelopathy: an approach for biological control of weeds.

Weed infestation is one of the most damaging biotic factors to limit crop production by competing with the crop for space, water, and nutrients. Different conventional approaches are being used to cope with weed infestation, including labor intensive manual removal and the use of soil-degrading, crop-damaging, and environment-deteriorating chemical herbicides. The use of chemicals for weed control has increased 2-fold after the green revolution and their non-judicious use is posing serious threats to mankind, animals, and biodiversity. The detrimental effects of these approaches have shifted the researchers' attention from the last two decades towards alternate, sustainable, and eco-friendly approaches to cope with weed infestation. The recent approaches of weed control, including plant and microbial allelopathy have gained popularity during last decade. Farmers still use conventional methods, but the majority of farmers are very passionate about organic agriculture and describe it as a slogan in the developed world. The effectiveness of these approaches lies in host specificity by selective bacteria and differential response towards weeds and crops. Moreover, the crop growth promoting effect of microorganisms (allelopathic bacteria) possessing various growth promoting traits, that is, mineral solubilization, phytohormone production, and beneficial enzymatic activity, provide additional benefits. The significance of this review lies in the provision of a comprehensive comparison of the conventional approaches along with their potential limitations with advanced/biological weed control approaches in sustainable production. In addition, the knowledge imparted about weed control will contribute to a better understanding of biological control methods.