Weed Management Programs Research Articles

Crop Residues Mulch as Organic Weed Management Strategy in Maize

Crop residues mulching can be opted for organic and sustainable weed management in maize. A 2‐year field study was conducted to evaluate the influence of different crop residues on weeds dynamics and productivity of maize under semi‐arid conditions. Chaffed herbage (2–3 cm) of four crops viz., sorghum, sunflower, rice, and maize was mixed in different combinations (each crop at a rate of 6 t ha−1) and was surface applied as mulch. A weedy check and s‐metolachlor + atrazine application treatments were also established for comparison. Infestation of weeds had a negative impact on maize growth and yield. Nevertheless, surface applied mulches were helpful in suppressing weed pressure and improving maize growth and yield performance. Among different mulching combinations, the rice + sunflower + maize herbage recorded the maximum reductions in density and dry biomass of horse purslane and purple nutsedge compared with weedy check control. Total weeds suppression by this treatment was almost similar with s‐metolachlor + atrazine application. A maximum increment in terms of crop growth rate, total dry matter accumulation and grain yield was observed due to the mulching of rice + sunflower + maize. All the mulching combinations significantly enhanced the quality of maize as compared with weedy check and the sorghum + sunflower + maize was more effective for maize quality. Taking together, the results depicted that crop residue mulches can effectively suppress weed growth along with enhancing growth, yield and quality of maize, suggesting that it can be successfully employed in organic weed management programs in maize.

The Critical Period for Weed Control (CPWC) in Potato (<i>Solanum tuberosum</i> L.)

Accurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used to assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.

Weed Control in Cotton by Combinations of Microencapsulated Acetochlor and Various Residual Herbicides Applied Preemergence

Residual herbicides are routinely recommended to aid in control of glyphosate-resistant (GR) Palmer amaranth in cotton. Acetochlor, a chloroacetamide herbicide, applied PRE, controls Palmer amaranth. A microencapsulated (ME) formulation of acetochlor is now registered for PRE application in cotton. Field research was conducted in North Carolina to evaluate cotton tolerance and Palmer amaranth control by acetochlor ME alone and in various combinations. Treatments, applied PRE, consisted of acetochlor ME, pendimethalin, or no herbicide arranged factorially with diuron, fluometuron, fomesafen, diuron plus fomesafen, and no herbicide. The PRE herbicides were followed by glufosinate applied twice POST and diuron plus MSMA directed at layby. Acetochlor ME was less injurious to cotton than pendimethalin. Acetochlor ME alone or in combination with other herbicides reduced early season cotton growth 5 to 8%, whereas pendimethalin alone or in combinations injured cotton 11 to 13%. Early season injury was transitory, and by 65 to 84 d after PRE treatment, injury was no longer noticeable. Before the first POST application of glufosinate, acetochlor ME and pendimethalin controlled Palmer amaranth 84 and 64%, respectively. Control by acetochlor ME was similar to control by diuron plus fomesafen and greater than control by diuron, fluometuron, or fomesafen alone. Greater than 90% control was obtained with acetochlor ME mixed with diuron or fomesafen. Palmer amaranth control was similar with acetochlor ME plus a full or reduced rate of fomesafen. Acetochlor ME controlled large crabgrass and goosegrass at 91 and 100% compared with control at 83 and 91%, respectively, by pendimethalin. Following glufosinate, applied twice POST, and diuron plus MSMA, at layby, 96 to 99% control was obtained late in the season by all treatments, and no differences among herbicide treatments were noted for cotton yield. This research demonstrated that acetochlor ME can be safely and effectively used in cotton weed management programs.

WATER USE EFFICIENCY, GROWTH AND YIELD OF WHEAT CULTIVATED UNDER COMPETITION WITH Setaria

ABSTRACT Understanding the critical period of weed competition is indispensable in the development of an effective weed management program in field crops. Current experiment was planned to evaluate the critical growth period ofSetaria and level of yield losses associated with delay in weeding in rain-fed drip irrigated wheat production system of Saudi Arabia. Field experiment was conducted to evaluate the effect of weeding interval (07-21, 14-28, 21-35, 28-42 and 35-49 days after sowing) and drought stress (75% and 50% of field capacity) on Setaria growth, wheat yield and water use efficiency. Season long weedy check and wellwatered (100% FC) plots were also maintained for comparison. Weeding interval and drought stress significantly (p ≤ 0.05) affected the growth and yield of Setaria and wheat. Drought stress from 75% to 50% FC resulted in reductions of 29-40% in Setaria height, 14-27% in Setaria density and 11-26% in Setaria dry biomass. All weeding intervals except 35-49 DAS significantly suppressedSetaria growth as compared with control. Delay in weeding increased weed-crop competition interval and reduced wheat yield and yield contributors. Therefore, the lowest yield of 1836 kg ha-1 was attained for weeding interval of 35-49 DAS at 50% FC. Water use efficiency and harvest index increased with decreasing FC levels but reduced with delay in weeding. Correlation analysis predicted negative association ofSetariadensity with wheat yield and yield contributors and the highest negative association was for harvest index (-0.913) and water use efficiency (-0.614). Early management of Setaria is imperative for successful wheat production otherwise yield losses are beyond economical limits.

Nonconventional Weed Management Strategies for Modern Agriculture

Weeds are a significant problem in crop production and their management in modern agriculture is crucial to avoid yield losses and ensure food security. Intensive agricultural practices, changing climate, and natural disasters affect weed dynamics and that requires a change in weed management protocols. The existing manual control options are no longer viable because of labor shortages; chemical control options are limited by ecodegradation, health hazards, and development of herbicide resistance in weeds. We are therefore reviewing some potential nonconventional weed management strategies for modern agriculture that are viable, feasible, and efficient. Improvement in tillage regimes has long been identified as an impressive weed-control measure. Harvest weed seed control and seed predation have been shown as potential tools for reducing weed emergence and seed bank reserves. Development in the field of allelopathy for weed management has led to new techniques for weed control. The remarkable role of biotechnological advancements in developing herbicide-resistant crops, bioherbicides, and harnessing the allelopathic potential of crops is also worth mentioning in a modern weed management program. Thermal weed management has also been observed as a useful technique, especially under conservation agriculture systems. Last, precision weed management has been elaborated with sufficient details. The role of remote sensing, modeling, and robotics as an integral part of precision weed management has been highlighted in a realistic manner. All these strategies are viable for today's agriculture; however, site-specific selection and the use of right combinations will be the key to success. No single strategy is perfect, and therefore an integrated approach may provide better results. Future research is needed to explore the potential of these strategies and to optimize them on technological and cultural bases. The adoption of such methods may improve the efficiency of cropping systems under sustainable and conservation practices.

Evaluation of Weed Management Programs and Response of FG72 Soybean to HPPD-Inhibiting Herbicides

Field experiments were conducted at two locations in Missouri in 2012 and 2013 to evaluate herbicide programs in 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor-resistant soybean, referred to as FG72 soybean, and their tolerance to four HPPD-inhibiting herbicides. At the Columbia location, PRE followed by (fb) POST and two-pass POST treatments provided 97% or greater control of all weeds except ivyleaf morningglory. At Moberly in 2012, PRE fb POST treatments provided 95% or greater control and 100% biomass reduction (BR) of glyphosate-resistant (GR) waterhemp, with the exception of isoxaflutole at 0.04 kg ha−1plusS-metolachlor at 0.6 kg ha−1plus metribuzin at 0.2 kg ha−1. In 2013, PRE fb POST treatments provided greater than 89% control and 93% BR. Two-pass POST treatments of isoxaflutole plus glyphosate always provided greater control and BR of GR waterhemp compared with glyphosate fb glyphosate. However, at Columbia, where glyphosate-susceptible weeds were present, there were no differences in control or BR between two-pass POST treatments. In the soybean tolerance experiment, isoxaflutole provided the lowest levels of injury. Applications of tembotrione at the 1× rate resulted in the greatest injury in both years. Topramezone at the 1× rate always provided less injury than tembotrione, but was always similar in BR. The 2× rates increased soybean injury over the 1× rate for the third trifoliate (V3) application, but not for the PRE and first-flower (R1) applications. V3 and R1 applications of isoxaflutole and mesotrione resulted in similar injury, height reduction, and BR to soybean 28 d after application in 2012 and 2013. Overall these results indicate that FG72 soybean could allow the use of HPPD-inhibiting herbicides such as mesotrione PRE along with isoxaflutole PRE and POST to provide an additional herbicide mechanism of action that was not previously available in soybean.

Study of <i>Parthenium hysterophorus</i> L. Extracts (First Clean-Up Fractions) on Seed Germination Behaviour in Search of Bioactive Fractions for Preparation of Bioherbicide Formulations

Increase in productivity is directly related with increase pesticide consumption. So there is a strong desire to use “greener” chemistry to produce more toxicologically and environmentally benign pesticides and natural products. In this present study, a comparison was made to evaluate the phytotoxicity potential of first cleanup fractions obtained from sequentially extracted solvent (ethyl-acetate, methanol) extracts of Parthenium hysterophorus L. (aerial parts) in vitro through bench-top seed germination assay (Vignaradiata L.). One-way analysis of variance (ANOVA) followed by Duncan’s multiple range test (DMRT) were done for statistical analysis of the data. The study reveals that germination, growth and vigour was significantly (P<0.05) reduced by ethyl-acetate and methanol fractions. A significant changes in soluble and insoluble sugar content, protein, amino acid content and cellular metabolic activity was aslo observed by 1F3, 1F4, 1F6, and 1F9 fractions. The present study concluded that phytotoxicity of four fractions (1F3, 1F4, 1F6, and 1F9) from ethylacetate and methanolic crude extracts of Partheniumhysterophorus could be exploited as potential bioherbicide for future weed management programme and the development of bioherbicide for commercial use.

Maximizing Weed Control in Florida Citrus

With Florida citrus growers and production managers being “squeezed” between rising production prices and declining yields from citrus greening, there’s more call than ever to reduce citrus production costs. Controlling weeds is a major expense, amounting to 11% of the total $2,278 annual production cost per acre for the 2014–2015 season. This revised 3-page fact sheet teaches the six essential components of an effective weed-management program to help maintain the profitability of this vital Florida industry. Written by Stephen H. Futch and Brent Sellers, and published by the Horticultural Sciences Department, September 2015.

Study of <i>Parthenium hysterophorus</i> L. Extracts (First Clean-Up Fractions) on Seed Germination Behaviour in Search of Bioactive Fractions for Preparation of Bioherbicide Formulations

Increase in productivity is directly related with increase pesticide consumption. So there is a strong desire to use “greener” chemistry to produce more toxicologically and environmentally benign pesticides and natural products. In this present study, a comparison was made to evaluate the phytotoxicity potential of first cleanup fractions obtained from sequentially extracted solvent (ethyl-acetate, methanol) extracts of Parthenium hysterophorus L. (aerial parts) in vitro through bench-top seed germination assay (Vignaradiata L.). One-way analysis of variance (ANOVA) followed by Duncan’s multiple range test (DMRT) were done for statistical analysis of the data. The study reveals that germination, growth and vigour was significantly (P<0.05) reduced by ethyl-acetate and methanol fractions. A significant changes in soluble and insoluble sugar content, protein, amino acid content and cellular metabolic activity was aslo observed by 1F3, 1F4, 1F6, and 1F9 fractions. The present study concluded that phytotoxicity of four fractions (1F3, 1F4, 1F6, and 1F9) from ethylacetate and methanolic crude extracts of Partheniumhysterophorus could be exploited as potential bioherbicide for future weed management programme and the development of bioherbicide for commercial use.

Row spacing impacts the critical period for weed control in cotton (Gossypium hirsutum)

The knowledge on the critical crop-weed competition period is important for designing an efficient weed management program. Field studies were conducted in 2012 and 2013 at the Agricultural Research Institute, Kahramanmaras, Turkey to determine the effects of three row spacing (50, 70 and 90 cm) on the critical period for weed control (CPWC) in cotton. A four parameter logistic equation was fit to data relating relative crop yield to both increasing duration of weed interference and length of weed-free period. The relative yield of cotton was influenced by the duration of weed-infested or weed-free period, regardless of row spacing. In cotton grown at 50 cm row spacing, the CPWC ranged from 117–526 growing degree days (GDD) (V2–V11 growth stages) in 2012 and 124–508 GDD (V2–V10) in 2013 based on the 5% acceptable yield loss level. At 70 cm row spacing, the CPWC ranged from 98–661 GDD in 2012 (V2–V13) and 144–616 GDD (V2–V12) in 2013. At 90 cm row spacing, the CPWC ranged from 80–771 GDD in 2012 (V1–V14) and 83–755 GDD (V1–V14) in 2013. In order to obtain a 95% weed-free yield, the weed management should start at 16 days after crop emergence (DAE) and continued until 52 DAE (V2–V11) for crops grown in 50 cm row spacing, 15 and 60 DAE (V2–V13) for 70 cm row spacing and 11 and 67 DAE (V1–V14) for crops grown in 90 cm row spacing. This suggests that cotton grown in narrow row spacing (50 cm) had greater competiveness against weeds compared with wider row spacing (70 and 90 cm). Cotton growers can benefit from these results by improving cost of weed control through better timing of weed management.

Effectiveness of Herbicides for Control of Hairy Vetch (Vicia villosa) in Winter Wheat

A field experiment was conducted in 2009–2010 at Pennsylvania and Maryland locations, and repeated it in 2010–2011 to test the effectiveness of POST-applied herbicides at fall and spring timings on seeded hairy vetch in winter wheat. A total of 16 herbicide treatment combinations was tested that included synthetic auxins, acetolactate synthase (ALS) inhibitors, and a protoporphyrinogen oxidase inhibitor. Spring applications tended to be more effective than fall applications. Among synthetic auxins, clopyralid (105 g ae ha−1) and treatments containing dicamba (140 g ae ha−1) were effective at both timings, resulting in greater than 90% hairy vetch control at wheat harvest. Pyroxsulam and prosulfuron applied at 18 g ai ha−1provided the most effective hairy vetch control (> 90%) at both application timings among ALS inhibitors. Spring applications of several herbicides provided moderate (> 80%) to high (> 90%) levels of hairy vetch control, including: 2,4-D amine (140 g ae ha−1), mesosulfuron-methyl (15 g ai ha−1), tribenuron-methyl (13 g ai ha−1), and thifensulfuron/tribenuron-methyl treatments (16 and 32 g ai ha−1). Winter wheat injury was evaluated, but symptoms were negligible for most treatments. Winter wheat yields declined with increasing hairy vetch biomass. Fall herbicides may be prioritized to reduce hairy vetch competition during the fall and early spring growing season. Our research has established that several synthetic auxin and ALS-inhibiting herbicides, applied POST in fall or spring, can be safely used in winter wheat to control hairy vetch in an integrated weed management program.

Evaluation of POST-Harvest Herbicide Applications for Seed Prevention of Glyphosate-Resistant Palmer amaranth (Amaranthus palmeri)

Recent increases in the prevalence of glyphosate-resistant (GR) Palmer amaranth mandate that new control strategies be developed to optimize weed control and crop performance. A field study was conducted in 2012 and 2013 in Jackson, TN, and in 2013 in Knoxville, TN, to evaluate POST weed management programs applied after harvest (POST-harvest) for prevention of seed production from GR Palmer amaranth and to evaluate herbicide carryover to winter wheat. Treatments were applied POST-harvest to corn stubble, with three applications followed by a PRE herbicide applied at wheat planting. Paraquat alone or mixed withS-metolachlor controlled 91% of existing Palmer amaranth 14 d after treatment but did not control regrowth. Paraquat tank-mixed with a residual herbicide of metribuzin, pyroxasulfone, saflufenacil, flumioxazin, pyroxasulfone plus flumioxazin, or pyroxasulfone plus fluthiacet improved control of regrowth or new emergence compared with paraquat alone. All residual herbicide treatments provided similar GR Palmer amaranth control. Through implementation of POST-harvest herbicide applications, the addition of 1,200 seed m−2or approximately 12 million seed ha−1to the soil seedbank was prevented. Overall, the addition of a residual herbicide provided only 4 to 7% more GR Palmer amaranth control than paraquat alone. Wheat injury was evident (< 10%) in 2012 from the PRE applications, but not in 2013. Wheat grain yield was not adversely affected by any herbicide application.

Early season weed mapping in sunflower using UAV technology: variability of herbicide treatment maps against weed thresholds

Site-specific weed management is defined as the application of customised control treatments only where weeds are located within the crop-field by using adequate herbicide according to weed emergence. The aim of the study was to generate georeferenced weed seedling infestation maps in two sunflower fields by analysing overlapping aerial images of the visible and near-infrared spectrum (using visible or multi-spectral cameras) collected by an unmanned aerial vehicle (UAV) flying at 30 and 60 m altitudes. The main tasks focused on the configuration and evaluation of the UAV and its sensors for image acquisition and ortho-mosaicking, as well as the development of an automatic and robust image analysis procedure for weed seedling mapping used to design a site-specific weed management program. The control strategy was based on seven weed thresholds with 2.5 steps of increasing ratio from 0 % (herbicide must be applied just when there is presence or absence of weed) to 15 % (herbicide applied when weed coverage >15 %). As a first step of the imagery analysis, sunflower rows were correctly matched to the ortho-mosaicked imagery, which allowed accurate image analysis using object-based image analysis [object-based-image-analysis (OBIA) methods]. The OBIA algorithm developed for weed seedling mapping with ortho-mosaicked imagery successfully classified the sunflower-rows with 100 % accuracy in both fields for all flight altitudes and camera types, indicating the computational and analytical robustness of OBIA. Regarding weed discrimination, high accuracies were observed using the multi-spectral camera at any flight altitude, with the highest (approximately 100 %) being those recorded for the 15 % weed threshold, although satisfactory results from 2.5 to 5 % thresholds were also observed, with accuracies higher than 85 % for both field 1 and field 2. The lowest accuracies (ranging from 50 to 60 %) were achieved with the visible camera at all flight altitudes and 0 % weed threshold. Herbicide savings were relevant in both fields, although they were higher in field 2 due to less weed infestation. These herbicide savings varied according to the different scenarios studied. For example, in field 2 and at 30 m flight altitude and using the multi-spectral camera, a range of 23–3 % of the field (i.e., 77 and 97 % of area) could be treated for 0–15 % weed thresholds. The OBIA procedure computed multiple data which permitted calculation of herbicide requirements for timely and site-specific post-emergence weed seedling management.

Herbicide-Based Weed Management Programs in Erect, Thornless Blackberry

Field studies were conducted in 2009/2010 and 2011 in North Carolina to determine the influence of herbicide-based weed management programs on weed control and blackberry tolerance. Treatments consisted of five programs with a late fall-early winter herbicide application followed by (fb) an early spring herbicide application: flumioxazin fb flumioxazin, simazine fb terbacil, terbacil fb oryzalin plus simazine, norflurazon fb oryzalin plus simazine, and terbacil fb S-metolachlor plus simazine. A sixth program consisted of winter-applied dichlobenil. Crop tolerance and weed control were recorded at the physiological crop stages of budbreak, flowering, and harvest.

Cost-benefit analysis blueprint for regional weed management: Nassella neesiana (Chilean needle grass) as a case study

We describe a bio-economic model for Nassella neesiana (Chilean needle grass) that estimates the net benefit of a containment programme for the weed in Canterbury as the difference between the cost of containment and the costs incurred over time should the weed spread within sheep and beef pastoral systems. Logistic spread is assumed with the maximum area that could be invaded (772,080 ha) determined by constraining a climate niche model for the weed to susceptible farm system types within productive land use capability classes. The current size of the invaded area (80 ha) was determined by field observations in Canterbury in 2008, and the spread rate (201 years to 90% saturation) was derived from observations in the adjacent Marlborough region. With these assumptions, and discounting at 8% per year over 100 years, the net benefit is negative NZ$173,178 ($83,900–$257,078) and containment would not be economically worthwhile. However, the net benefit is positive over a range of lower discount rates and higher spread rates, revealing a need for robust estimates of these parameters. The model presented here provides a generic blueprint for meeting the requirements of the Biosecurity Act with respect to evaluating proposed regional weed management programmes.

Nitrogen application influenced the critical period for weed control in cotton

The critical knowledge of crop-weed competition period is important for designing weed management strategies in cropping systems. Field experiments were conducted in 2012 and 2013 growing seasons at the Agricultural Research Institute, Kahramanmaras, Turkey to determine the effect of three nitrogen (N) rates (0, 150 and 300 kg N ha−1) on the critical period for weed control (CPWC) in cotton. A four parameter log-logistic model was fit to the two sets of relating relative crop yield to data obtained from increasing durations of weed interference and lengths of weed-free period. In both the years and regardless of the N application rate, the relative yield of cotton decreased with increasing duration of weed-interference and increased with increasing duration of weed-free period. The application of N fertilizer delayed the beginning of the CPWC in cotton. At the 0 kg N ha−1, the CPWC ranged from 44 to 537 GDD (growing degree days) (7–51 days after crop emergence [DAE]) in 2012 and 87–605 GDD (14–57 DAE) in 2013 based on the 5% acceptable yield loss. At the 150 kg N ha−1, the CPWC ranged from 124 to 597 GDD (18–56 DAE) in 2012 and 183–551 GDD (22–49 DAE) in 2013. Depending on the N application rate, weed-free conditions need to be established as early as one week after crop emergence and maintained as late as eight weeks after crop emergence to avoid more than 5% loss in cotton yield. These findings could help cotton producers improve the cost effectiveness and efficacy of their weed management programme under different N application rates.

Switchgrass Establishment and Biomass Yield Responses to Fungicide and Insecticide Seed Treatments

Switchgrass (Panicum virgatum L.) is being evaluated for both forage and bioenergy in the Great Plains of the USA. Management strategies to improve switchgrass seedling vigor and emergence may result in more successful switchgrass stands due to better competitive advantage for switchgrass seedlings over weedy species. The objectives of this field experiment were to determine the effects of seven broad‐spectrum fungicide and insecticide seed treatments on the establishment and yield of lowland type ‘EG1101’ switchgrass. The combination of fungicide + insecticide (regardless of formulation) tended to result in taller seedlings and greater seedling densities and stands of switchgrass as compared to untreated control (UTC), fungicide only, and insecticide only. These advantages didn’t result in greater switchgrass dry matter (DM) yield, probably due to adequate stands (>1–2 plants per ft2) that were achieved by all fungicide–insecticide seed treatments including UTC. However, given the relatively small cost per acre of seed treatments, there may be early‐season benefits to treating seeds with a broad‐spectrum insecticide as an insurance measure to increase switchgrass seedling vigor and reduce the chance of stand failure, especially when used with a proven weed management program.

Management options of invasive Elodea nuttallii and Elodea canadensis

Elodea nuttallii and Elodea canadensis , two invasive submerged and rooted aquatic macrophyte species, are receiving increasing attention for their rapid and lasting invasion of many freshwater habitats throughout Europe, Asia and Australia. This review summarizes the present scientific knowledge about means of controlling E. nuttallii and E. canadensis within of aquatic weed management programs. Both species exhibit high growth rates with a high tolerance to wide ranges of environmental conditions, low vulnerability to grazing and other stress factors, high distribution and reproduction potential, and relatively high resistance to common conventional aquatic weed management procedures. Possibilities for the further use of harvested Elodea biomass are presented and novel approaches to the improvement of the monitoring and management of Elodea plagues are discussed.

The Critical Period for Weed Control: Revisiting Data Analysis

There is an ever-larger need for designing an integrated weed management (IWM) program largely because of the increase in glyphosate-resistant weeds, not only in the United States but also worldwide. An IWM program involves a combination of various methods (cultural, mechanical, biological, genetic, and chemical) for effective and economical weed control (Swanton and Weise 1991). One of the first steps in designing an IWM program is to identify thecritical period for weed control(CPWC), defined as a period in the crop growth cycle during which weeds must be controlled to prevent crop yield losses (Zimdahl 1988).

Eco-Friendly Weed Control Options for Sustainable Agriculture

Background: Weeds are unwanted plants playing a very important role in different eco-systems and many of them cause enormous direct and indirect losses. The losses include interference with cultivation of crops, loss of biodiversity, loss of potentially productive lands, loss of grazing areas and livestock production, erosion following fires in heavily invaded areas, choking of navigational and irrigation canals and reduction of available water in water bodies. Weed management takes away nearly one third of total cost of production of field crops. In India, the manual method of weed control is quite popular and effective. Of late, labour has become non-availability and costly, due to intensification, diversification of agriculture and urbanization. The usage of herbicides in India and elsewhere in the world is increasing due to possible benefits to farmers and continuous use of the same group of herbicides over a period of time on a same piece of land leads to ecological imbalance in terms of weed shift and environmental pollution. The complexity of these situations has resulted in a need to develop a wholistic sustainable eco-friendly weed management programme throughout the farming period. Objectives: This study reviews the different approaches used in sustainable weed control options. Conclusion: Sustainable farming has the ability to save the natural resources for the future and develop the farm in the little expense, a transition to sustainable weed control is required for environmental, social and economic reasons and sustainable weed management is socially acceptable, environmentally benign and cost-effective.