Volume-55 | Issue-1(January-March)| Year 2023

Bibliographic analysis, Invasive alien weeds, Modelling, Species distribution modelling

Invasive alien weeds are of great concern because of their capability of spreading fast, their high competitiveness and ability to settle in new areas within short period of time. Thus, they are the second biggest threat to biodiversity after habitat destruction. It is therefore necessary to prevent the introduction, establishment, and spread of these invasive alien weeds (IAWs) into newer areas. Ecological niche modelling (ENMs) and species distribution modelling (SDMs) are two commonly used approaches in theoretical and applied studies in ecology to study the species behavior in future climatic conditions. In this study, we undertook a bibliographic analysis of scholarly articles on the modelling studies on species invasion under current and future climatic scenarios. In addition, results of different studies on modelling and prediction on distribution of IAWs on global as well as India level were also discussed. Study revealed that researchers started getting interest and published more work in the subject between 2015 and 2020. The greater number of related articles were published in the subjects such as ecology, biology, habitat and climate change and published mostly by Wiley, Elsevier and Springer publishers.  Further, the shortcomings of species distribution modelling and future prospects were also discussed. 

Cultivars competitiveness, Hybrids, Rice, Varieties, Weed management

Weed competitive ability of six rice cultivars including three hybrids [Arize 6129 (short duration); Arize 6444 (medium duration), Arize Dhani (long duration)] and three varieties [Swarna Shreya (short duration); Rajendra Sweta (medium duration); MTU 7029 (long duration)] was evaluated under three weed pressures i.e. low weed pressure [pre-emergence application (PE) of pretilachlor 0.60 kg/ha at 2 days after transplanting (DAT) followed by (fb) post-emergence application (PoE) of bispyribac-sodium 30 g/ha at 20 DAT  fb 1 hand weeding (HW) at 35 DAT; medium weed pressure (pretilachlor PE at 2 DAT  fb bispyribac-sodium PoE at 20 DAT) and high weed pressure (weedy check)]. Experiment was conducted during rainy seasons of 2018 and 2019 at the ICAR-Research Complex for Eastern Region Patna, Bihar. The major weeds recorded with transplanted rice were Brachariaria ramosa, Trianthema portulacastrum, Cyperus rotundus, Echinochloa colona, Caesulia axillaris and Physalis minima. Rice hybrids, viz. Arize 6444 and Arize Dhani, and rice variety Swarna Shreya recorded significantly lower weed biomass compared to other varieties. Weeds reduced rice grain yield by 31.37%. Long-duration and short statured rice variety MTU 7029 was more susceptible to weed competition compared to other varieties and hybrids. Early duration hybrid Arize 6129 recorded low weed pressure, maximum rice grain yield (6.57 t/ha) and economic returns.

Direct-seeded rice, Florpyrauxifen-benzyl + cyhalofop-butyl, Herbicide, Weed management, Wet-seeded rice

Weed infestation is the major yield limiting factor in direct wet-seeded rice (WSR). Herbicides use is gaining acceptance among the farmers as it is easy, economical, time saving, and efficient to manage weeds. The herbicide mixtures with different modes of action are preferable to use in rotation. An experiment was conducted to evaluate and identify a suitable pre-mix herbicide mixture and its dosage rate to get optimum weed management and rice yield in WSR during  wet seasons of 2017 and 2018 at research farm of ICAR–National Rice Research Institute, Cuttack, Odisha, India using randomized complete block design with three replications. Nine treatments were tested including: viz. post-emergence application (PoE) of florpyrauxifen-benzyl + cyhalofop-butyl at 120, 150, 180 and 360 g/ha; florpyrauxifen-benzyl at 25 and 30 g/ha PoE; bispyribac-sodium 30 g/ha PoE; weed free and weedy check. Among the herbicide treatments, florpyrauxifen-benzyl + cyhalofop-butyl 150 g/ha PoE was most effective to control weeds with the lowest weed density, biomass, and weed index, lower weed persistence index and highest weed control index, weed control efficiency, crop resistance index, treatment efficiency index and weed management index at 60 days after sowing in WSR with higher rice grain yield, and was at par with the weed free. In weedy check, 40% rice yield loss was recorded. Thus, florpyrauxifen-benzyl + cyhalofop-butyl 150 g/ha PoE may be recommended for effective weed control in direct wet-seeded rice. 

Allelopathy, Cultural management, Organic wheat, Plant extract, Weed management

Weed management is a major constraint in organic wheat production systems and integration of non-herbicidal weed management practices is the only available option. The present study was conducted at two locations during 2019-20 to evaluate the efficiency of allelopathic water extracts coupled with cultural practices in managing the weeds in organic wheat. The treatments consisted of two wheat varieties (tall and dwarf) and seven weed management treatments. The taller wheat variety PBW 677 had significantly lower weed biomass (21.4 to 28.2%) at harvest and higher grain yield (7.4 to 15.4%) than the dwarf variety Unnat PBW 550 and recorded better net returns and B:C at both the locations. Among the weed management treatments, hand weeding twice recorded maximum reduction in weed density (44.6 to 46.2%), and weed dry biomass (44.6% to 58.2%) at 75 days after sowing (DAS). The next best treatment in reducing weed density (38.9 to 45.3%) and dry biomass (41.1 to 46.5%) was line sowing of pre-germinated wheat seeds + wheel hoeing. This was followed by line sowing of pre-germinated wheat seeds + plant extract spray. The corresponding increases in wheat grain yields with above mentioned treatments at location I and II, compared to weedy check, were 69.6 and 66%; 42.7 and 51.8%, and 17.7 and 30.7%, respectively. Under labour constrained situations, line sowing of pre-germinated wheat seeds followed by wheel hoeing or application of mixed plant extract of sorghum, sunflower and raya at 18 L/ha each at 25 and 50 DAS of wheat can provide effective weed management, higher grain yield and better economic returns in organic wheat production.

Atrazine, Economics, Maize, Tembotrione, Weed control efficiency, Weed management

A field experiment was conducted at Punjab Agricultural University, Krishi Vigyan Kendra, Pathankot, Punjab, India during Kharif 2016 and 2017 to identify the best herbicides-based weed management practices in maize (Zea mays L.). The treatments consisted of pre-emergence (PE) application of atrazine 1000 g/ha, pendimethalin 750 g/ha, pendimethalin 750 g/ha + atrazine 750 g/ha and post-emergence (PoE) application of tembotrione 110.2 g/ha, tembotrione 110.2 g/ha + atrazine 625 g/ha and 2,4-D amine salt 580 g/ha, hand weeding twice at 15 and 30 days after sowing (DAS) and weedy check. A randomized complete block design with three replications was used. The tembotrione 110.2 g/ha + atrazine 625     g/ha (tank mix) PoE at 25 DAS recorded the highest weed control efficiency (94.2%), maize grain yield (4.43 t/ha), net monetary returns ( 28047.3) and B:C (1.77).

Atrazine, Allelopathic water extracts, Herbicide combination, Halosulfuron-methyl, Sugarcane, Weed Management

A field experiment was conducted during 2016-17 and 2017-18 at Agricultural Research Farm of Institute of Agricultural Sciences, BHU, Varanasi. The experiment was laid out in split plot design with five treatments in main plots and five treatments in sub plots. In main plots, there were five herbicide combinations, viz. pre-emergence application (PE) of atrazine 2 kg/ha at 3 days after planting (DAP) followed by (fb) post-emergence application (PoE) of halosulfuron-methyl 150 g/ha at 45 DAP, metribuzin 2 kg/ha fb halosulfuron-methyl 150 g/ha, triazinone 1.0 kg/ha fb halosulfuron-methyl 150 g/ha, weed free and weedy check. In sub-plots, five aqua based plant/allelopathic extracts were tested, viz. cow urine (500 L/ha), parthenium extract (15%), sunflower + sorghum + maize extract (15%), eucalyptus extract (15%) and water (600 L/ha). The lowest weed density and biomass, weed index (WI), NPK uptake by weeds and the highest weed control efficiency (WCE) were recorded with atrazine 2 kg/ha PE fb halosulfuron-methyl 150 g/ha PoE in combination with sorghum + sunflower + maize extract, while need based hand weeding recorded higher cane yield.

Cotton, Economics, Mechanical weeding, Pendimethalin, Power tiller, Pyrithiobac-sodium, Weed management

Field experiments were conducted under irrigated condition during winter seasons of 2020-21 and 2021-22 (September to February) at Cotton Research Station, Tamil Nadu Agricultural University, Srivilliputtur to study the comparative efficacy of mechanical and chemical weed management methods in cotton. Six treatments were evaluated in a randomized block design with four replications. The treatments consisted of control (no weeding), weed free check, pre-emergence application of (PE) pendimethalin at 1.0 kg/ha followed by (fb) one hoeing at 45 days after sowing (DAS), pendimethalin at 1.0 kg/ha fb post-emergence application (PoE) of pyrithiobac-sodium at 62.5 g/ha at 25 DAS fb one hoeing at 45 DAS, weeding by power tiller at 25 and 45 DAS, pendimethalin PE at 1.0 kg/ha fb weeding by power tiller on 25 and 45 DAS. Pendimethalin PE fb pyrithiobac-sodium PoE fb one hoeing recorded the higher cotton growth and yield attributes except boll weight along with lesser weed density and biomas and higher weed control efficiency. This was on par with that of pendimethalin PE fb weeding by power tiller at 25 and 45 DAS and pendimethalin PE fb one hoeing at 45 DAS and significantly superior than weeding by power tiller at 25 and 45 DAS. Application of PE fb PoE herbicide fb one hoeing also registered the highest seed cotton yield which were comparable with that of pendimethalin fb weeding by power tiller at 25 and 45 DAS. The cost of cultivation was drastically reduced by mechanical weeding. The economic analysis showed that higher net income and benefit cost ratio were associated with PE herbicide application fb weeding by power tiller at 25 and 45 DAS followed by weeding by power tiller at 25 and 45 DAS. 

Cotton, Stale seed bed technique (SSBT), Cover crops, Legumes, Weed management

Integrated weed management approach is preferable to manage weeds effectively and economically. A study was carried out at Central Institute for Cotton Research, Regional station, Coimbatore to study the efficacy of stale seed bed technique (SSBT) in integration with weed smothering legumes as cover crops (CC) in managing weeds of irrigated cotton production system. The experiment was conducted during winter season of 2015-16 and 2016-17 cropping season in a randomized block design with four replications. Six weed control treatments viz., SSBT + CC - Mimosa invisa, SSBT + CC - Crotalaria juncea, SSBT + CC- Sesbania aculeata, SSBT + CC -Vigna unguiculata , SSBT + CC - Desmanthus virgatus along with one hand weeding (HW) at 30 days after seeding (DAS) was common to all cover crop treatments. They were compared against pre-emergence application (PE) of pendimethalin 1.0 kg/ha at 3 DAS followed by (fb) hand weeding twice at 30 and 60 DAS. The weed pressure was reduced significantly with SSBT integrated with leguminous cover crops when compared to currently recommended practice of pendimethalin PE fb hand weeding twice. The integration of SSBT to exhaust weed seed bank and growing of leguminous cover crops like Crotalaria juncea and Vigna unguiculata to smother weeds reduced weed pressure and hence recommended as an effective, sustainable weed management options in irrigated cotton production system

Greengram, Herbicides, Pendimethalin + imazethapyr (ready-mix), Weed management

A field study was conducted to assess the effect of different sole and ready-mix herbicides on weeds and productivity of summer greengram in Odisha,  during summer season of 2020 and 2021 at Agricultural Research Station, Chatabar, Faculty of Agricultural Sciences, IAS, SOADU, Bhubaneswar. Eight treatments, viz. pre-emergence application (PE) of pendimethalin 0.75 kg/ha at 1 day after sowing (DAS),  post-emergence application (PoE) of imazethapyr 75 g/ha at 20 DAS, pendimethalin + imazethapyr 0.75 kg/ha PE at 1 DAS, quizalofop-ethyl 50 g/ha PoE at 20 DAS,  fenoxaprop-p- ethyl 50 g/ha PoE at 20 DAS, sodium-acifluorfen 16.5% + clodinafop-propargyl 8% 245 g/ha PoE at 20 DAS, hand  weeding twice at 15 and 30 DAS and weedy check, were replicated thrice in the randomized block design.  Hand weeding twice at 15 and 30 DAS registered significantly lowest density and biomass of all categories of weeds as well as total weeds and it was closely followed by pendimethalin + imazethapyr (ready-mix) 0.75 kg/ha PE. Pendimethalin PE and imazethapyr PoE recorded at par value of density and biomass of grasses, broad-leaved and total weeds. Hand weeding twice at 15 and 30 DAS registered the highest seed yield (1076 kg/ha) of greengram along with higher yield attributing characters like number of pods/plant (29.23), seeds/pod (7.90) and number of branches/plant (8.88) and it was closely followed by pendimethalin + imazethapyr (ready-mix) 0.75 kg/ha PoE. Highest net return ( 39,809/ha) and return per rupee invested (2.12) was registered  with  pendimethalin + imazethapyr (ready-mix) 0.75 kg/ha PE. 

Blackgram, Haloxyfop, Herbicides, Phytotoxicity, Rice, Weed management

Blackgram (Vigna mungo (L.) Hepper) is one of the most remunerative legume crop which grown in Kharif or summer season. An experiment was conducted to evaluate the activity and selectivity of the post-emergence herbicide haloxyfop on weeds growth and blackgram productivity during Kharif season of 2015 and 2016 at N.E. Borlaug Crop Research Centre, G.B.P.U.A& T, Pantnagar, Uttarakhand. The  grass weeds: Echinochloa colona (15.5 and 15.0%), Eleusine indica (48.6 and 32.3%), Dactyloctenium aegyptium (18.3 and 22.0%), Digitaria sanguinalis (3.5 and 6.4%), Brachiaria spp. (2.8 and 3.3%) and Panicum maximum (11.3 and 21.0%) dominated the field (during 2015 and 2016, respectively).The lowest weed density and biomass, and highest weed control efficiency and blackgram seed yield were recorded with post-emergence application (PoE) of haloxyfop  135 g/ha followed by and at par with its lower dose (108 g/ha) during both the years and  statistically at par with standard check quizalofop-ethyl 50g/ha, only during 2015. No phytotoxicity occurred to blackgram on 1, 3, 5, 7, 10, 15 and 30 days after application at any of the tested haloxyfop doses and was found safe for growing succeeding transplanted rice as rice growth and yield were not affected by any of the doses of haloxyfop. 

Internal Transcribed Spacer (ITS), Molecular diagnosis, Orobanche aegyptiaca, Parasitic plant, Rapeseed-Mustard, Soil testing

Orobanche are the devastating holoparasitic weeds causing extensive damage to the mustard cultivation in India. Considering the tedious species identification from a single seed and seed longevity in the soil for years, the mitigation of this weed is difficult. Therefore, development of molecular diagnostic assay specific to Orobanche aegyptiaca is required for weed management. In this study, a polymerase chain reaction (PCR) based strategy was optimised using internal transcribed spacer (ITS) based markers to identify the Orobanche species predominant in the mustard fields. Genomic DNA was extracted from tissue and soil samples artificially inoculated with seeds of Orobanche spp. and subjected to PCR analysis. ITS primers amplified a 350bp PCR product specific to O. aegyptiaca confirming its dominance in mustard crop fields of India. Furthermore, soil and tissue samples were collected from the seven farmer fields of Rajasthan and subjected to PCR analysis using ITS-350 primers. ITS-350 primers amplified all the soil/tissue samples confirming the specificity of the method and markers applied. It was also found that one Orobanche plant could attach itself to the host plant through many haustoria and also many Orobanche plants could attach to the one mustard plant through individual haustorium. This assay can also be applied to identify seed contaminants in commercial seed lots. A small soil sample taken from the mustard field can provide clues about the infestation likely to affect crop yield and productivity. Based on diagnosis suitable recommendations for crop management and input on fertilizer doses can be provided to the farmers on timely basis. 

Economics, Pendimethalin, Seed purity, Tithonia diversifolia, Sesame, Weed management 

Weed control is an important component of crop management as it determines the crops productivity, quality and the profitability. A field trial was conducted in 2019 rainy season at Research and Training Farm of Centre for Dryland Agriculture, Bayero University Kano (BUK) (11°58'52.5" N and 008°24'48.6") and National Horticultural Research Institute at Bagauda, Kano (11°33’25.93" N and 008°23’11.97" E), Nigeria. The experiment was aimed at evaluating weed management strategies effect on quality and profitability of sesame production. Eleven weed management treatments were laid out in randomized complete block design replicated thrice. Weedy check recorded the largest number of broad-leaved, grasses and sedges weed species in both locations. The pre-emergence application (PE) of pendimethalin followed by (fb) a hoe weeding at 6 weeks after seeding (WAS) recorded the highest sesamum seed yield, seed oil contents and physical purity when compared to other weed control treatments at both locations. Hoe weeding twice at 3 and 6 WAS had the highest seed yield (1223 kg/ha and 1212 kg/ha), total variable cost ($973 and $963) and gross revenues ($1065 and $1056) than other weed control treatments, at both the locations. Hoe weeding twice at 3 and 6 WAS resulted into higher seed yield, but it is not economical due to labour cost involved. Pendimethalin 1.0kg/ha PE fb post-emergence application (PoE) of Tithonia diversifolia (Hemsl.) A. Gray leaf extract 5% w/v at 6 WAS had higher net return ($309 and $317) and benefit cost ratio (1.50 and 1.52) proving to be more economical and could therefore be recommended in the study area.

Cashew orchards, Cote D’Ivoire, Weeds survey, Weed diversity, Weed infestation

The cashew orchards development and productivity faces several constraints, which include weeds. This study aims to assess the degree of infestation of weeds in cashew orchards by monitoring their density, richness and diversity in 108 cashew orchards in four regions of Côte d’Ivoire. In each plot of the 100 m² of each of the cashew orchards selected, weeds were identified and the individuals of herbaceous species were collected and counted whereas the trees and shrubs were counted without being up rooted. There were 295 weeds species belonging to 194 genera and 58 families of angiosperms. Regional data revealed 101 species and 50629 individuals in the Bounkani, 165 species and 70618 individuals in the Kabadougou, 156 species and 13597 individuals in the Gontougo and 164 species and 196257 individuals in Marahoué. A high negative relation was found between the orchards’ age and the weeds infestation level in the cashew orchards.

Cost saving, Garlic, Narrow crop weeder, Raised beds, Weed control factor, Weed management

Currently, manual weeding is done in garlic, with hand tools like Khurpi or hand pulling which is a cumbersome operation. The cost of weeding by manual method alone accounts for more than one-fourth of the total cultivation cost in garlic. Tractor drawn mechanical weeding helps reduce time consumption and drudgery of manual weeding in non-herbicidal growing systems. A soil bin study with laboratory model weeder was carried out to investigate the effect of number of tines (soil working tool), depth of operation and forward speed of simulated weeds on weed control factor (WCF). The experimental study showed that the number of tines, depth of operation and forward speed significantly affected the WCF and it increased with an increase of all the three parameters. Three tines operated at 75 mm depth at 3 km/h speed gave the maximum value of WCF. Depth of operation of tine was the predominant factor influencing the WCF. Based on the soil bin investigation, tractor-drawn weeder was developed with multiple flexible round tines that vibrate perpendicular to the tractor direction to remove weeds from the soil. Developed weeder was evaluated for managing weeds in garlic crop grown on raised beds. The effective field capacity and field efficiency were observed as 0.18 ha/h and 76.62%, respectively, at forward speed of 2 km/h. The plant damage and weeding efficiency was observed as 1.61 and 68.64%, respectively. The cost saving due to usage of the developed weeder, in comparison with the existing manual weeding, was 51.3%. The machine has potential for adoption by farmers growing garlic on raised beds. 

Economics, Herbicides, Turfgrass, Weed management

A field experiment was conducted to test the efficacy of different weed control treatments on control of turfgrass weeds in the established lawn of Bermuda grass ‘Selection No. 1’ at Punjab Agricultural University, Ludhiana during winter and summer seasons of 2021. The experiment was laid out in a randomized complete block design with 15 treatments i.e., post-emergence application (PoE) of isoproturon 0.937 kg/ha, mesosulfuron + iodosulfuron 0.014 kg/ha, clodinafop + metribuzin 0.216 kg/ha, 2,4-D amine 0.50 kg/ha, bispyribac-sodium  0.025 kg/ha, metribuzin 0.120 kg/ha, metsulfuron 0.005 kg/ha, carfentrazone-ethyl 0.020 kg/ha, metsulfuron + carfentrazone-ethyl 0.025 kg/ha, metsulfuron-methyl + chlorimuron-ethyl 0.004 kg/ha, ethoxysulfuron 0.018 kg/ha, halosulfuron 0.050 kg/ha, atrazine 1.0 kg/ha, hand weeding twice at 15 days interval and weedy check. The PoE of isoproturon 0.937 kg/ha, mesosulfuron + iodosulfuron 0.014 kg/ha, clodinafop + metribuzin 0.216 kg/ha, bispyribac-sodium 0.025 kg/ha, metribuzin 0.120 kg/ha and ethoxysulfuron 0.018 kg/ha provided complete control of Poa annua, a winter season weed, which was at par with hand weeding twice, whereas, in summer season, clodinafop + metribuzin  0.216 kg/ha  PoE reduced the density and biomass of Digitaria sanguinalis and Dactyloctenium aegyptium. Bispyribac-sodium 0.025 kg/ha was found effective against Dicanthium annulatum. Metsulfuron + carfentrazone-ethyl 0.025 kg/ha PoE provided complete control of broad-leaved weeds, viz. Gnaphalium purpureum, Oxalis corniculata, Desmodium triflorum, Coronopus didymus in winter season and Boerhavia diffusa and Alysicarpus vaginalis in summer season. Halosulfuron 0.050 kg/ha PoE effectively controlled Cyperus rotundus upto 45 days after spray (DAS) during winter season. Metsulfuron + carfentrazone-ethyl 0.025 kg/ha PoE recorded highest weed control efficiency (WCE) (72.9 %) during winter, whereas in summer clodinafop + metribuzin 0.216 kg/ha PoE recorded highest WCE. Sward height and dry biomass of turfgrass were found negatively correlated with the weed biomass in both of seasons. Phyto-toxicity was observed with clodinafop + metribuzin (0.216 kg/ha) PoE, however, the grass recovered after 35 DAS in winter season.

Greengram, Sulfosulfuron, Weed management, Wheat, Zero tillage

An experiment was conducted on zero-till (ZT) wheat grown after greengram at Jhansi during 2019-20. Broad-leaved weeds dominated (90-95%) the field, with limited occurrence of grassy weeds (5-10%). Weed density was higher under conventional tillage (CT) than ZT. Wheat grain yield was the highest under ZT, but there was no effect of greengram residue along with ZT. Pre-emergence application (PE) of pendimethalin followed by (fb) post-emergence application (PoE) of sulfosulfuron provided effective control of weeds, and improved weed control efficiency (88.2–90.5%). Herbicidal efficiency index also was maximum with pendimethalin PE fb sulfosulfuron PoE. The improved profitability with enhanced productivity of wheat can be achieved with ZT with application of glyphosate before sowing wheat after greengram and usage of sulfosulfuron PoE for controlling weeds. The greengram residues along with ZT may prove beneficial in the long-run.

Crop residues, Economics, Maize hybrids, Planting methods, Weed management, Zero-tillage

A field experiment was conducted at Chaudhary Charan Singh Haryana Agricultural University, Regional Research Station, Karnal during rainy season (Kharif ) 2015. Two planting methods, viz. zero tillage and raised beds each with and without residues were evaluated with three maize hybrids (HQPM-1, HM-4 and HM-10) and two weed management treatments viz. pre-emrgence application (PE) of atrazine 750 g/ha followed by (fb) hand weeding (HW) at 30 days after seeding (DAS) and unweeded check, in a split plot design. Dactyloctenium aegyptium, Brachiaria reptans, Eragrostis tenella, Portulaca oleracea, Ammania baccifera and Cyperus rotundus along with some other broad-leaved weeds  (BLW) predominated the experimental field. Zero tillage with residues and atrazine 750 g/ha PE fb 1 HW at 30 DAS recorded the lowest density and biomass of weeds, at 20 and 40 DAS, greater number of grains/cob, grain yield and net returns. However, the benefit- cost ratio (B:C) was maximum with zero tillage without residue. Lower weed density was observed with maize hybrid HM-10 and HM-4 as compared to HQPM-1. The minimum biomass of BLW, maximum number of grains/cob, grain yield, net returns and B:C were observed with hybrid HM-4, while the minimum biomass of grassy weeds and sedges was with HM-10. 

Cultivars, Green fodder yield, Inter cropping, Maize, Row spacing, Tembotrione, Weed management

A field experiment was conducted at Forage Research Farm, Department of Plant Breeding and Genetics, PAU, Ludhiana and Regional Research Station, Gurdaspur during the Kharif season of 2020 in fodder maize to evaluate the impact of different weed management treatments on the relationship amongst weed parameters, fodder maize crop characters and green fodder yield. Green fodder yield of maize showed a significant positive correlation with weed control efficiency, maize plant dry weight and plant height. On the contrary, these parameters were negatively correlated with the weed density and biomass at the knee high stage of the crop. The average of the two locations indicated that a unit increase in weed density and biomass reduced maize fodder yield by 0.0655 and 0.083 t/ha, respectively. Similarly, the increase in the maize fodder yield due to a unit increase in weed control efficiency was estimated at 0.166 t/ha.

Cowpea, Establishment method, Imazamox + imazethapyr, Line sowing, Weed management

 A field study was carried out at College of Agriculture, Vellanikkara during October- December 2020 to study the effect of different crop establishment and weed management methods on the productivity of cowpea. Treatment consisted of two crop establishment methods, viz. broadcast seeding and line sowing and six weed management treatments, viz. hand weeding twice 20 and 40 days after seeding (DAS), post-emergence application (PoE) of imazethapyr + imazamox (pre-mix) 40 g/ha at 15-20 DAS, imazethapyr + imazamox 40 g/ha (pre-mix) PoE at 15- 20 DAS followed by (fb) hand weeding at 40 DAS, imazethapyr 40 g/ha PoE at 15- 20 DAS, imazethapyr, 40 g/ha PoE at 15- 20 DAS fb hand weeding 40 DAS and unweeded control. The highest cowpea yield was recorded with hand weeding twice (937.67 kg/ha), followed by imazethapyr + imazamox 40 g/ha PoE at15- 20 DAS fb hand weeding (877.30 kg/ha). Line sown crop recorded higher cowpea yield compared with broadcasting. Imazethapyr + imazamox 40 g/ha PoE at 15- 20 DAS fb hand weeding at 40 DAS use in broadcasted seeded and line sown cowpea resulted in higher grain yield, net return and B:C and hence can be recommended as a cost effective weed management practice for enhancing productivity of broadcasted seeded and line sown cowpea. 

Mulching, Onion, Oxyfluorfen, Pendimethalin, Weed management

Onion (Allium cepa L.) is a widely grown vegetable crop in India. Onion production is severely affected by the weed menace which hampers onion growth and yield. A study was conducted at Birsa Agricultural University, Ranchi during 2018 to identify the best feasible method for weed management in onion. Treatments tested include: plastic mulch, available weed mulch at 6t/ha, paddy straw mulch at 7 t/ha, cover crop, pre-emergence application (PE) of oxyfluorfen 0.5 kg/ha, pendimethalin 1 kg/ha PE, mechanical weeding, hand weeding and weedy check. Amongst the treatments, black plastic mulch was found to be most effective in controlling weeds with minimum weed density and biomass, weed index (%) and highest weed control efficiency (%) as compared to other treatments. Onion grown with black plastic mulch showed better onion growth in terms of maximum plant height, number of leaves/plant, neck thickness and maximum onion yield attributes like average bulb weight, average bulb diameter and bulb yield. However, pendimethalin PE recorded highest net returns and B:C as it was cost effective.

2,4-D amine salt, Glyphosate, Non-cropped areas, Oxyfluorfen, Paraquat, Weed management 

A field experiment was conducted during rainy season in 2019-20 at Navsari Agricultural University, Navsari to identify efficient herbicides and their combinations to manage weeds in non-crop situation. The experiment was laid out in a randomized block design replicated thrice with seven weed management treatments involving herbicides i.e. glyphosate, paraquat, oxyfluorfen, 2,4-D amine salt along with mowing and weedy check. All treatments significantly reduced the weed density and biomass compared to weedy check. Glyphosate 3.0 kg/ha effectively controlled weeds registering negligible weed biomass at 60 days after application (DAA). Glyphosate 2.0 kg/ha alone or in combination with 2,4-D amine salt 2.0 kg/ha (tank-mix) and glyphosate + oxyfluorfen 2.0 kg/ha (ready-mix) were at par in their efficacy to control weeds up to 60 DAA and up to 30 DAA, respectively. Paraquat 4.0 kg/ha and paraquat 2.0 kg/ha + 2,4-D salt 2.0 kg/ha (tank-mix) were found effective up to two weeks only. Thus, glyphosate 2.0 kg/ha alone or in combination with 2,4-D amine salt 2.0 kg/ha (tank-mix) may be used to effectively minimize the weeds biomass and resurgences significantly up to 60 DAA with highest weed control efficiency. 

Chocolate weed, Insects mortality, Leachate, Pulse beetle, Rice weevil, Storage pests, Weeds usage  

Insecticidal potential of whole plant leachate of chocolate weed (Melochia corchorifolia L.) on storage pests, viz. Callosobruchus maculatus (F.) and Sitophilus oryzae (L.) was assessed under laboratory conditions. Results revealed that whole plant leachate of M. corchorifolia had insecticidal action against C. maculatus and S. oryzae. Mortality rate of storage pests was found to be concentration dependent and the highest leachate concentration (15 %) resulted in significantly higher mortality rate. LC50 and LC 95  values  for the mortality of  rice weevils and pulse beetles after 48 h of treatment were 11.69, 15.50 mg/L and 32.89 and 43.45 mg/L, respectively. The result clearly indicated the presence of a toxicant or growth inhibitor principle in the whole plant leachate of M. corchorifolia. Identification and isolation of active ingredient in the whole plant leachate of M. corchorifolia will help to develop an eco-friendly biopesticide against C. maculatus and S. oryzae.