Efficacy Of Different Herbicides Research Articles

Herbicide Strategies for Weed Control in Rice Cultivation: Current Practices and Future Directions

Rice, as a staple food for more than half of the world's population, plays a crucial role in global food security. However, weed competition poses a significant challenge to rice cultivation, affecting yield and quality. To address this challenge, rice farmers have increasingly turned to chemical herbicides as a cost-effective alternative to labor-intensive manual weeding. This review paper explores the current practices and future directions in herbicide strategies for weed control in rice cultivation, with a specific focus on diverse approaches adopted in various agro-ecological regions, particularly in Pakistan. The paper begins by highlighting the importance of rice cultivation in global agriculture and the economic significance of the crop, emphasizing the need for effective weed management to ensure sustainable production. It discusses the impact of labor shortages and rising labor costs on weed control practices, driving the adoption of chemical herbicides, especially in direct-seeded rice cultivation. Additionally, the review underscores the importance of integrated weed management systems, which combine cultural practices, targeted herbicide applications, and legislative measures to optimize crop productivity while minimizing environmental impact. Furthermore, the paper evaluates the efficacy of different herbicides and their timing of application in managing weeds and maximizing rice yield. It synthesizes findings from recent studies to provide insights into the effectiveness of pre-emergence and post-emergence herbicides, as well as their impact on weed-crop competition and overall crop health. By analyzing the strengths and limitations of existing herbicide strategies, the review identifies opportunities for innovation and improvement in weed management practices. Overall, this review paper offers a comprehensive overview of herbicide strategies for weed control in rice cultivation, highlighting the need for sustainable and integrated approaches to address weed challenges while ensuring food security and environmental sustainability in rice-producing regions.

Efficacy of different herbicides for controlling grass predominant weed flora and achieving higher production in dual purpose linseed under mid hills of Himachal Pradesh

A field experiment was conducted to study the effect of herbicide treatments on the weed flora and the production of the dual-purpose Linseed. The results revealed that grassy weeds viz., Phalaris minor, Lolium temulentum and Avena ludoviciana constituted 43.2, 23.2 and 17.2% of the total weed flora at 90 DAS. Among the broadleaf weeds, Vicia sativa and Spergulla arvensis constituted about 8.4% of total weed flora. As the crop was mainly infested with grassy weeds, effective control of total weeds with the application of clodinafop 60 g/ha (Post.), pendimethalin 1.0 kg/ha (Pre.) and isoproturon 1.25 kg/ha (Post.) as equivalent to hand weeding twice resulted in significantly higher seed, straw, biological, oil and fibre yield of Linseed. As far as the economics is concerned, significantly higher net returns of ₹ 54401 and 3051/ha and net returns per rupee invested (2.01 and 1.90) were obtained by statistically similar treatments of clodinafop 60 g/ha (Post.) and pendimethalin 1.0 kg/ha (Pre.), respectively. Thus, depending upon the situation in dual-purpose Linseed, selecting either of these appropriate chemicals is the better option for controlling grass-predominant weed flora and obtaining higher yields (seed and fiber) with better returns.

Efficacy of Herbicides, Their Effects on Rice Yield Under Saturated Soil Condition

This study was carried out in containers which were placed outdoor to evaluate the efficacy of different herbicides with different mixtures on weed growth suppression in rice and their effects on rice grain yield under saturated soil water regime in two consecutive seasons (cropping season and off season) at the Universiti Putra Malaysia Farm, Serdang, Selangor, Malaysia during 2016 to 2017. Eight combinations of different herbicides, viz. T1, T2, T3, T4, T5, T6, T7 and T8 along with weed free and non-weeded treatments were used in the study following a RCBD. Weed composition in the experimental containers and their summed dominant ratio (SDR) at 60 days after planting were recorded from non-treated containers. Naturally grown eleven weed species mainly under the families of Poaceae, Cyperaceae and Pontederiaceae were found in the experimental containers. Based on the SDR values the dominant weed species were Monochoria vaginalis, Echinochloa crus-galli, and Fimbristylis miliacea in both the seasons. Results revealed that four herbicide treatments viz. Pretilachor fb Bentazon/MCPA (T1), Pretilachor+Pyribenzoxim fb Bentazon/MCPA (T2). Bispyribac-sodium fb Bentazon/MCPA (T2), Fenoxaprop+Ethoxysulfuron (T3), fb Bentazon/MCPA (T7) were superior in their effectiveness for weed control in both seasons and gave better rice grain yield with high economic return. Bangladesh J. Bot. 52(1): 37-44, 2023 (March)

Herbicide mixtures for post-emergence control of horseweed in coffee interrow

Glyphosate-resistant biotypes of horseweed (Conyza spp.) have been a constant problematic for coffee growers all over Brazil. Therefore, this work was developed with the objective of evaluating efficacy of different herbicides, applied isolated or in mixture, for horseweed control in coffee plantation interrows. A field trial was performed with the following treatments (g ha-1): glyphosate at 925, glufosinate-ammonium (GA) at 500, saflufenacil at 49, flumioxazin at 50, glyphosate + GA (925 + 500), glyphosate + saflufenacil (925 + 49), glyphosate + flumioxazin (925 + 50), GA + saflufenacil (500 + 49), GA + flumioxazin (500 + 50) and glyphosate + saflufenacil + clethodim (925 + 49 + 108), besides check plots without herbicide application. The treatment with clethodim was included considering a possible concomitant presence of sourgrass (Digitaria insularis (L) Fedde) in the areas. At the moment of herbicide application, horseweed was 40 cm tall in pre-flowering. Percent control was evaluated at 7, 14, 21 and 28 days after application (DAA), as well as mass of dry matter at 28 DAA. In general, adequate control of horseweed was obtained with glufosinate-ammonium applications, isolated or in mixture with glyphosate, saflufenacil or flumioxazin. Mixture of glyphosate and saflufenacil has also reached high control of horseweed infestation, without difference to GA treatments. As conclusion, horseweed infestations in coffee interrow may be efficiently controlled with tank mixtures of herbicide.

Effectiveness and selectivity of herbicides applied under preemergence conditions in weed management for coffee crops

The coffee plant is sensitive to weed competition, which negatively affects its growth and development. Thus, the proper and safe use of herbicides is extremely important for weed management to allow the crop to develop its maximum productive potential. The objective of this study was to evaluate the control efficacy of different herbicides under pre-emergence conditions and assess their selectivity for coffee crops. Two experiments were carried out in the field, in randomized block designs, with four replicates and eight treatments, totaling 32 experimental plots. The treatments were: unweeded control; weeded control; sulfentrazone + diuron 1.4 L ha-1; sulfentrazone + diuron 1.7 L ha-1; sulfentrazone + diuron 2.0 L ha-1; sulfentrazone + diuron with indaziflam 1.4 + 0.15 L ha-1; respectively, indaziflam 0.15 L ha-1; and oxyfluorfen + chlorimuron 3.0 L ha-1 + 0.08 kg ha-1, respectively. The treatments wereapplied prior to the emergence of weeds in a directed spray between the crop rows. Evaluations of weed control in the area, phytotoxicity to the crop, branch length, and internode distance of coffee were conducted at 30, 60, 90, and 120 days after treatment application (DAA). In general, all treatments guaranteed greater than 80% efficacy up to 60 DAA. After this, some treatments suffered reductions in efficacy, and did not guarantee satisfactory control up to 120 DAA. For Digitaria nuda, the most effective treatments were those that contained indaziflam alone or in combination with sulfentrazone + diuron, and oxyfluorfen + chlorimuron for 60 DAA. In both experiments and the two species analyzed, the indaziflam treatments guaranteed efficacy percentages above 80%, even at 120 DAA. All treatments were equally selective for the coffee plants under the conditions evaluated. Key words: Coffea arabica; Chemical control; Phytotoxicity.

Effectiveness of Herbicide to Control Rice Weeds in Diverse Saline Environments

To mitigate environmental pollution and food contamination caused by inappropriate and excessive herbicide usage, most potent herbicides should be screened to control rice weeds. A research trial was executed for assessing the comparative efficacy of different herbicides to control rice field weeds and to evaluate the toxicity on rice under normal (distilled water) as well as different salinity levels (4 and 8 dS m−1). The study was designed to select the most potent herbicide and its appropriate dose for weed control of rice crop in coastal areas. Fourteen herbicidal treatments were included weed free crop, Pretilachlor (0.25, 0.50, 0.375 and 0.75 kg a.i. ha−1), Propanil + Thiobencarb (0.6 + 1.2, 0.9 + 1.8, 1.2 + 2.4 and 1.8 + 3.6 kg a.i. ha−1), Bensulfuron + MCPA (0.03 + 0.05, 0.045 + 0.075, 0.06 + 0.1 and 0.09 + 0.15 kg a.i. ha−1) and weedy check (control). The results revealed that all tested herbicides in higher than recommended doses for non-saline rice fields were effective in controlling Cyperus iria, Echinochloa colona (salt-tolerant) and Jussiaea linifolia but showed in light injury in rice plants grown in non-saline soils. These higher doses of herbicides recorded severe crop injury under saline conditions indicating their differential efficacy from normal non-saline conditions. Treatments including Pretilachlor (0.375kg a.i. ha−1), Propanil + Thiobencarb (0.9 + 1.8 kg ai/ha), Bensulfuron + MCPA (0.06 + 0.1 kg a.i. ha−1) and Pretilachlor (0.50 kg a.i. ha−1) remained superior in terms of weed control and grain yield production under all salinitylevels at TanjungKarang, Malaysia. It is concluded that herbicides respond differently under saline conditions and optimization of their doses potentially prevent herbicidal injury in rice plants.

Control of Ailanthus altissima using cut stump and basal bark herbicide applications in an eighteenth‐century fortress

AbstractThe Cittadella di Alessandria (Italy) is a military fortification that was built in the 18th century. The site has recently been abandoned and is now colonised by weeds, including the invasive Ailanthus altissima. The aim of the study was to compare the efficacy of different herbicides (glyphosate, a mixture of aminopyralid + fluroxypyr and triclopyr + fluroxypyr) applied to cut stumps or to the basal bark of A. altissima. For the cut stump application, plants were first cut at the base and then immediately sprayed and for the basal bark application, the lower 50 cm of the plants was sprayed with the herbicides; untreated cut plants were used as a control, for comparison. Two runs per study were carried out (in summer 2015 and in spring 2016). Efficacy was assessed up to 2018 by counting the resprouts and their height in the cut stump application and, for the basal bark treatment, by measuring the variation in the plant circumference after treatment. The cut stump treatment carried out in summer greatly reduced the number of resprouts, compared to the spring treatment, to less than one sprout per plant when aminopyralid + fluroxypyr was used, and its efficacy lasted for about two years. The basal bark treatment did not control the species, but lower levels of variation in circumference and greater mortality were detected in plants treated with aminopyralid + fluroxypyr. Considering the high level of infestation of the site and the high risk of plant resprouting, repeated cut stump treatments with aminopyralid + fluroxypyr would be preferable to eradicate this invasive species.

Efficacy of different herbicides on weed dynamics and productivity of kharif maize (Zea mays) and their residual effect on succeeding wheat crop (Triticum aestivum)

Weeds are the major biotic constraints in maize crop due to its wider row spacing limiting its productivity. So, a field experiment was conducted during kharif and rabi seasons of 2015 and 2016, at RRS, Karnal, Haryana to study the effect of different weed control methods on weed flora, growth and yield of kharif planted maize, the residual effect of different herbicides applied in maize on succeeding wheat crop. Treatments included two pre-emergence (PRE) herbicides namely atrazine 750 or 1000 g/ha and alachlor 2000 g/ha along with three post-emergence herbicides (POST) atrazine 500 g/ha, 2,4-D 500 g/ha and tembotrione 120 or 140 g/ha +S (surfactant) at 35 days after sowing (DAS) were used. Hand weeding twice at 20 and 35 DAS, weedy check and weed free treatments were also included. Major weed species infesting the experimental field were Cyperus rotundus, Brachiaria reptans, Dactyloctenium aegyptium, Amaranthus viridis, Digera arvensis, Phyllanthus niruri and Portulaca oleracea. Among herbicide treatments at 50 DAS, alachlor 2000 g/ha as PRE fb tembotrione 120 g/ha provided the highest weed control efficiency (95.1 %). Maximum grain yield (6505 and 6903 kg/ha) and yield attributes of maize were obtained in weed free treatment which was statistically at par with alachlor 2000 g/ha fb tembotrione 120 g/ha +S at 35 DAS (T13) (6380 and 6816 kg/ha). No visual phyto-toxicity of any applied herbicide was observed on maize crop. All herbicide treatments employed in kharif maize, irrespective of their dose and application time did not show any residual carryover effect on succeeding wheat crop.

Efficacy of Different Herbicides on Echinochloa colona (L.) Link Control and the First Case of Its Glyphosate Resistance in Greece

E. colona is a C4 annual summer grass which is troublesome to major summer annual and perennial crops. Due to recent complaints by the farmers, the objectives of the present study were to evaluate the efficacy of penoxsulam, profoxydim, cycloxydim, cyhalofop-butyl, florpyrauxifen-benzyl and glyphosate against six E. colona accessions, and also to evaluate the response of these accessions to different rates of glyphosate in a dose-response experiment. In the first experiment, herbicides were applied at their maximum recommended label rates, while in the dose-response experiment, glyphosate was applied at six doses corresponding to 0, 1/4X, 1/2X, X, 2X, and 4X of the recommended rate. The dry weight of the biotypes TH8 and TH7 treated with profoxydim was 66% and 68% of the untreated control, respectively. The efficacy of cyhalofop-butyl against three accessions was lower than 30%, while two accessions were susceptible to this herbicide. The efficacy of penoxsulam against the biotypes ET2 and ET4 was lower than 10%, while dry weight of FT5 and TH8 was only reduced by 23%–28% as compared to the control. Cycloxydim application provided control higher than 75% at 21 days after treatment (DAT) of three accessions, while the majority of E. colona accessions was adequately controlled by the application of florpyrauxifen-benzyl. The response of the different accessions to glyphosate varied. The results of the glyphosate dose-response experiment revealed that the GR50 values of the resistant E. colona accessions ET2 and ET4 were up to 1098 and 1220 g a.e. ha−1 of glyphosate, respectively, whereas the GR50 value of the susceptible accession (FT5) was only 98 g a.e. ha−1. The resistance indices of ET2 and ET4 were 12.4 and 11.2, respectively, indicating that they have already developed resistance to glyphosate. Three more accessions could be also of developing resistant to glyphosate. This is the first report of glyphosate resistance from E. colona accessions in Greece, with indications of multiple resistance also present. Further research is needed in order to evaluate the efficacy of several herbicides under different soil and climatic conditions, conduct baseline sensitivity studies, reveal the evolvement of resistance patterns to glyphosate from accessions of Echinochloa spp., and search for alternative options of weed management in annual and perennial crops due to the clear indications of multiple resistance situations.

Evaluation of chemical weed control options in broadcast and drill sown direct seeded rice

Being a resource conservation technology under rice-wheat cropping system, increasing water crisis, lack and high cost labor forced grower to grow rice directly into the field called as direct seeded rice (DSR). High weed infestation impeded the adoption of direct seeded rice by farmers. Various tillage practices, stale seed bed, best selection of competitive rice cultivar, water management, hand weeding and mechanical weeded are components strategies to control weeds in DSR. In this perspective, one option to control weeds through herbicides. Therefore, a field study was conducted to evaluate the efficacy of pre and post emergence herbicides under different sowing methods. Application of bispyribac-sodium + benzsulfuron methyl as post-emergence (POST) following pre herbicides (Ethoxysulfuron ethyl) or as tank-mixture with bispyribac-sodium + benzsulfuron methyl and Oxadiargyl effectively reduced the density and biomass accumulation of diverse weed flora in DSR. High grain yield and 1000 grain weight was recorded in the same treatment under drill sown method of rice plantation. It has been concluded that bispyribac-sodium + benzsulfuron ethyl as post-emergence (POST) following PRE herbicides (Ethoxysulfuron ethyl) or as tank-mixture with bispyribac-sodium + benzsulfuron and Oxadiargyl not only reduce weed biomass and density but also increase the total number of tillers, plant height, number of grains per panicle, 1000 grain weight and grain yield under drill sown method of DSR. The objective of present study was to examine the efficacy of different herbicides applied alone or in sequence to reduce weeds infestation in broadcast and drill sown direct seeded rice. Keywords: Direct seeded rice; Herbicides; PRE; POST; Weed management http://dx.doi.org/10.19045/bspab.2020.90152

Evaluation of accord plus and Lanfida for control of Chenopodium spp. in wheat

(Triticum aestivum L.) is the world’s most widely cultivated and leading staple food. But their production is continuously decreased due to infestation of grassy and broadleaf weeds. Chenopodium album is most dominant broadleaf weed of wheat and other Rabi crops. Which limit the production of Rabi crops. Therefore, there is need to know about the current status of herbicide resistance/poor efficacy of different herbicides against C. album. The present investigation was conducted during the Rabi season of 2017-18 in the screen house of Department of Agronomy Chaudhary Charan Singh Haryana Agricultural University, Hisar (Haryana). Pot experiment was conducted in completely randomized design, replicated thrice using different herbicides namely Accord Plus and Lanfida applied at three doses (0.5X, X and 2.0X) in the experiment as post-emergence. Untreated pots were maintained as control for comparison. The results in general indicated that Chenopodium populations have poor efficacy was observed with Lanfida; however application of Accord Plus recorded complete control. Higher value of plant height, chlorophyll fluorescence, fresh weight and dry weight and lower value of EC was observed in the herbicidal treatments showing poor efficacy against the test populations. Accord Plus post-emergence (POE) application of other herbicides has already been recommended and promoted for the management of Chenopodium populations.

Bio-efficacy of different herbicides in cluster bean

A field experiment “Efficacy of different herbicides in cluster bean” was conducted during the kharif seasons of 2018 and 2019 at Research Farm of RRS, Rohtak. Major weed flora in experiment includes Trianthema portulacastrum, Digera arvensis, Echinochloa colona, Amaranthus viridies etc. The season long growth of weeds reduced cluster bean yield up to 43.4 % and 44.6% during 2018 and 2019, respectively as compared to weed free condition. Sequential application of clethodium 120 g/ha 4 WAS resulted into significantly higher visual weed control and better crop yield as compared to alone application of pendimethalin 1000 g/ha PRE, whereas alone application of imazethapyr 70 g/ha PRE and imazethapyr + imazamox (RM) 70 g/ha PRE remained at par with it including weed free conditions during both the years of study. Thus, alone application of imazethapyr 70 g/ha PRE and imazethapyr + imazamox (RM) 70 g/ha PRE may be more economical and suitable for getting higher weed control and cluster bean yield avoiding one more application of herbicides as sequential application.

Effectiveness of herbicides against weeds and their residual effect on soil and carrot (Daucus carota)

An experiment was conducted to study the efficacy of different herbicides for weed control in carrot (Daucus carota L.) and their residual effect on soil as well as on crop, at Research Farm of CCS Haryana Agricultural University, Hisar (2012–13 and 2013–14). Thirteen treatments includes pre-emergence application of three herbicides, viz. oxyfluorfen and oxadiargyl (80, 100, 120 g/ha and 100 g/ha + HW), and pendimethalin (1.0 kg/ha and 1.0 kg/ha + HW), two weedings at 30 and 60 DAS, weed free and weedy check (control) are replicated three times in Randomized Block Design. Residues of these herbicides were estimated in soil and root samples, using GC-MS/MS. Based on two years pooled data it was concluded that pre-emergence application of oxadiargyl 100 g/ha, oxyfluorfen 100 g/ha and pendimethalin 1.0 kg/ha integrated with one hand weeding at 30 DAS resulted in effective weed control (70–72%) in carrot without any phytotoxicity on crop and gave 79.5, 77.2 and 76.4% higher root yield over weedy check, respectively. The residues of these herbicides in soil, carrot root as well as in foliage were found below detectable level at the time of harvest.

Evaluation of different herbicides against weeds in mungbean (Vigna radiata L.)

A field experiment was conducted during kharif season of 2016 at Mahatma Gandhi Chitrakoot Gramodaya Vishwavidyalaya, Chitrakoot, Satna (M.P.) to study the efficacy of different herbicides against weeds in mungbean. The weed density recorded at 30 and 60 DAS was significantly lower under pendimethalin 30 EC + imazethapyr 2 EC (Ready mix) 0.75 kg/ha as pre-emergence (PE) followed by pendimethalin PE. However, significantly lower weed dry weight and statistically superior weed control efficiency were noted in twice hand weeding at 20 DAS and 40 DAS and pendimethalin + imazethapyr (R.mix.) 0.75 kg/ha at same stages of crop (30 and 60 DAS). While, yield attributes viz. pods/plant (21.8) was significantly higher in plot treated with imazethapyr 10 SL @ 40g/ha applied at 20 DAS and statistically at par with imazamox 35 WG+ imazethapyr 35 WG 60g/ha applied at 20 DAS and clodinafop - propargyl 8% + aciflourfen - sodium 16.5% (WP) 187.5 kg/ha applied at 20 DAS. Application of clodinafop - propargyl 8% + aciflourfen - sodium 16.5% (WP) 187.5 kg/ha at 20 DAS produced significantly maximum seed yield (531 kg/ha) of mungbean closely followed by imazethapyr 10 SL @ 40g/ha at (528 kg/ha) and pendimethalin 30 EC + imazethapyr 2 EC (R.mix) 0.75 kg/ha (521 kg/ha). However, stover yield (2699 kg/ha), gross returns (`58464/ha) and net returns (`43163/ha) were obtained significantly superior under clodinafop - propargyl 8% + aciflourfen - sodium 16.5% (WP) 187.5 g/ha.

Influence of integrated weed management on weed dynamics and productivity of chili

A field experiment was carried out at Vegetable Research Farm, Mahrajpur, Department of Horticulture, JNKVV, Jabalpur (M.P.) to study the efficacy of different herbicides and mulches against weeds in chili, It was recorded that dominant weed flora in the experiment was Eragrostis cillansis and Cyperus rotindus among monocot weeds, Chenopodium album, Melilotus alba, Anagallis aruensis and Parthenium hysterophorus among dicot weeds. Highest weed density of all the weed species, dry weed biomass were recorded in weedy check plots. Pendimethalin @ 1.5 l/ha + black polythene mulch resulted in the highest plant height (75.3 cm), number of primary branches per plant (15.66), number of fruits per plant (73.33), yield of red ripe fruit (134.7q/ha-1) and yield of dry fruit (22qha-1) followed by Pendimethalin @ 1.5 l/ha + paddy straw mulch. Therefore, pendimethalin @ 1.5 l/ha + black polythene mulch resulted in the most effective treatment in terms of weed suppression and yield enhancement of chili crop.

Efficacy of pre- and post-emergence herbicides on complex weed flora in direct-seeded rice (Oryza sativa) in the eastern plains

The efficacy of different herbicides as tank mixture was evaluated to control diverse and complex weed flora in direct-seeded rice (Oryza sativa L.) during 2014-2016 at research farm of ICAR Research Complex for Eastern Region, Patna. Pendimethalin followed by tank mixture of bispyribac + ethoxysulfuron provided better control on diverse weed flora under direct seeded rice (DSR), except some of the typical grassy weeds with a yield of 4.4 tonnes/ha and was followed by tank mixture application of bispyribac + azimsulfuron (4.0 tonnes/ha) with an increment of yield by 83 and 67 % over plots receiving pendimethalin alone (2.4 tonnes/ha). Tank mixture application of bispyribac +2, 4-D and fenoxaprop + ethoxysulfuron (3.8 t/ ha) also produced 58% more grain yield over pendimethalin treated plots. It was also observed that pendimethalin followed by bispyribac in isolation could not able tocontrol Trianthemaportulacastrum effectively (69/m2) but when applied in combination with ethoxysulfuron or azimsulfuron haseffectively controlled this species (18 and 25/m2). Strong negative correlation (r = -0.96, P < 0.001) was obtainedbetween weed dry matter at 45 days after sowing and yield during the years of experimentation. With linear regression, it was observed that rice crop likely to produce less than 40% grain yield if weed dry matter is more than 200 g/m2. Pendimethalin followed by bispyribac + ethoxysulfuron mixture produced similar grain yield (4.4 tonnes/ha) as that of weed free situation (4.5 tonnes/ha). At farmers' field bispyribac + ethoxysulfuron tank mixture produced significantly higher grain yield (4.3 tonnes/ha) as compared to bispyribac alone (3.3 tonnes/ha) and weedy check (2.2 tonnes/ha) too. The tank mixture of bispyribac with ethoxysulfuron needs further evaluation at different locations as the particular mixture has got potential to control diverse and complex weed flora in direct seeded rice.

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Herbicide efficacy for aquatic Alternanthera philoxeroides management in an early stage of invasion: integrating above‐ground biomass, below‐ground biomass and viable stem fragmentation

SummaryAlternanthera philoxeroides is a problematic invasive plant in many regions of the world that is difficult to control once naturalised. It poses a threat to agricultural productivity, biodiversity and social amenity values of aquatic environments. Significant research has been conducted internationally, regarding the efficacy of different herbicides for control of A. philoxeroides. However, no studies have looked at key aspects of control for effective management in an early stage of invasion of aquatic environments, hindering eradication and control programmes. This study evaluates the efficacy of herbicides and surfactants on key A. philoxeroides response metrics, including control of above‐ground biomass, below‐ground biomass and production of viable stem fragments. This study concluded that glyphosate (isopropylamine salt) minimises viable stem fragment production post‐herbicide application, compared with imazapyr and metsulfuron, thus reducing the potential for dispersal throughout catchments and waterways. In contrast, imazapyr and metsulfuron provided more effective control than glyphosate for A. philoxeroides growing on exposed embankments. We propose that an effective management strategy for early invasion of aquatic A. philoxeroides, using herbicides, would be to conduct initial applications of glyphosate to control overwater biomass and limit dispersal of viable stem fragments. Once infestations have been forced back to the embankment, imazapyr or metsulfuron treatments will provide longer term control.

Efficacy of different herbicides for controlling narrow leave weeds in wheat -crop at different locations under adaptive research zone Sheikhupura

Field experiment was conducted at three locations i.e. Adaptive Research Farm and two at farmers field during Rabi 2014-15 under ecological zone of Adaptive Research Farm Sheikhupura to study the efficacy of different post emergent herbicides against narrow leave weeds. The experiment was carried out in randomized complete block design (RCBD) with three repeats. Present study comprised of five treatments including control. The treatments comprised of Axial (penoxadin), Exit (clodinofop propargyl), Brake (fenoxaprop-p-ethyl), Proton (Isoproturon) and weedy check. The data were recorded on Plant height at maturity (cm), no. of grains per spike, spike length (cm), weed density m-2, 1000 grains weight (g), and grain yield (t ha-1). All treatments of herbicide significantly control the weeds causing significant reduction in weed mass and also improved the grain yield significantly in comparison with the check at three locations. Highest death of weeds (96.12, 97.09 and 98.95 %) and with maximum grain yield of 2846.7, 3320.0 and 3300.0 kg ha-1 which is 19.6, 39.6 and 39.9 % higher than weedy check were recorded in the penoxadin treated plot at three locations respectively. In the weedy check the weed density was 51, 126 and 127 weeds m-2 with grain yield 2380, 2376 and 2358 kg ha-1 at three locations respectively. Keywords: Wheat; Wheat weed density; Yield; Yield components; Herbicides http://dx.doi.org/10.19045/bspab.2017.60053

Evaluation of efficacy of different herbicides on weed dynamics and performance of dwarf fieldpea in Tarai soils of Uttarakhand, India

A field experiment was conducted during rabi season of 2010-2011 and 2011-12 at Pantnagar in tarai soil of Uttarakhand to study the effect of different herbicides on plant growth, weed dynamics, nutrient uptake and yield of dwarf fieldpea. Results revealed that uncontrolled weeds caused 27.3 and 39.4 per cent reduction in grain yield of dwarf fieldpea during first and second year, respectively as compared to two hand weedings done at 20 and 40 days after sowing (DAS). Among the chemical treatments, minimum nutrient removal of 3.0 kg N,0.5 kg P and 3.3 kg K ha-1by weeds was recorded under pendimethalin 1.0kg ha-1 (PE)+ imazethapyr 0.05 kg ha-1 (POE,30 DAS) as against 11.4 kg N, 1.96 kg P and 12.6 kg K ha-1, respectively in weedy check Two hand weedings done at 20 and 40 DAS, which remained at par with pendimethalin1.0 kg ha-1 (PE) + imazethapyr 0.05 kg ha-1 (POE, 30 DAS) and pendimethalin 1.0kg ha-1(PE) + quizalofop ethyl 0.05kg ha-1(POE, 30 DAS) caused significant reduction in weed dry weight and increased the value of plant height, number of leaves per plant and dry matter accumulation per plant as compared to weedy check. These treatments produced 27.1, 23.1 and 16.0 per cent more number of pods/plant and yielded 50, 40 and 35.7 per cent higher grain yield, respectively over weedy check. The maximum weed control efficiency was computed under two hand weedings followed by pendimethalin 1.0 kg ha-1 (PE)+ imazethapyr 0.05kg ha-1 (POE, 30 DAS) and pendimethalin 1.0kg ha-1 (PE)+ quizalofop ethyl 0.05 kg ha-1 (POE, 30 DAS).