A field experiment was conducted during Kharif  (rainy season) 2014 and 2015 at Zonal Agricultural Research Station, V.C. Farm, Mandya, to identify suitable weed management practices for wet (drum)-seeded rice under Southern dry zone of Karnataka. Among the various treatments, pre-emergence application of bensulfuron-methyl 0.6% + pretilachlor 6% GR10 kg/ha fb post-emergence application of bispyribac sodium 25 g/ha at 20 days after sowing (DAS) being on par with weed free check, recorded significantly higher net monetary returns and B: C ratio.  Uncontrolled weed growth caused 48.23-50.0% reduction in grain yield of wet (drum)-seeded rice.

Bispyribac-sodium, Economics, Sequential application, Weeds, Wet (drum)-seeded rice

Tank mixing of herbicides is commonly practiced by farmers for control of a wide spectrum of weeds to save labour and reduce cultivation costs. However, little is known of the probable effects of herbicide mixing on herbicide efficacy. Field experiments were conducted in 2019-20 and 2020-21 in the Kole area of Thrissur district, Kerala, India to assess the feasibility of tank mixing of commonly used herbicides. The treatments involved tank mixtures and sequential applications of fenoxaprop-p-ethyl, chlorimuron-ethyl + metsulfuron-methyl, carfentrazone, bispyribac-sodium, and cyhalofop-butyl + penoxsulam. Hand-weeded and unweeded controls were also included for comparison. Tank mixing of fenoxaprop-p-ethyl with broad-leaf herbicides reduced its efficacy against Echinochloa colona, as compared to sequential application. The mixture of cyhalofop-butyl + penoxsulam with chlorimuron-ethyl + metsulfuron-methyl was more effective against E. colona than the former applied alone. This mixture also caused greater biomass reduction of Cyperus iria as compared to the sole application of cyhalofop-butyl + penoxsulam. Tank mixing of fenoxaprop-p-ethyl with bispyribac-sodium was more effective against Echinochloa stagnina and C. iria as compared to their sequential application, but this mixture was less effective against E. colona. A similar trend was observed with total weed biomass production. Highest rice yield attributes and grain yield (3.97 t/ha) were recorded with tank mixed application of cyhalofop-butyl + penoxsulam and chlorimuron-ethyl + metsulfuron-methyl, followed by the mixture of fenoxaprop with bispyribac-sodium. 

Bispyribac-sodium, Carfentrazone, Chlorimuron-ethyl, Metsulfuron-methyl, Cyperus iria, Echinochloa colona, Fenoxaprop-p-ethyl

Field experiments were conducted during Rabi (winter season) 2018-19 and 2019-20 to study the effect of sequential application of herbicides on productivity and profitability of transplanted rice. Pre-emergence (PE) application of pretilachlor 750 g/ha fb ready-mix post-emergence (PoE) application of triafamone + ethoxysulfuron 60 g/ha recorded significantly higher grain yield which was found to be at par with two hand weedings. Sequential application of pretilachlor 750 g/ha fb triafamone + ethoxysulfuron 60 g/ha proved to be more effective in minimising total weed biomass (5 g/m2), weed index (4%) and enhancing weed control efficiency (96%), grain yield (5.4 t/ha), net returns (47.0 x103 /ha) and benefit cost ratio (1.9) than weedy check. Tank-mix application of fenoxaprop-p-ethyl 60 g/ha with ethoxysulfuron 18.75 g/ha or chlorimuron + metsulfuron 4 g/ha after pretilachlor 750 g/ha showed phytotoxicity at 5 days after application (DAA) of herbicide, which got recovered at 30 DAA.

Grain yield, Phytotoxicity, Post-emergence herbicide, Weed control efficiency

Manipulation of crop fertilization with weed management is a promising agronomic practice in reducing weed interference in crops. With this hypothesis, an experiment was conducted at the Birsa Agricultural University, Ranchi, Jharkhand, India during rainy seasons (Kharif) of 2018 and 2019 to study the effect of nutrient and weed management practices on dry direct-seeded rice under split plot design. 100:50:40 kg/ha of N:P:K along with pretilachlor 750 g/ha (pre-emergence) fb bispyribac-Na 25 g/ha (post-emergence) recorded highest grain yield (5.54 t/ha)owing to higher effective tillers and grains/panicle to the extent of 73.5 and 82.8 percent, respectively compared to the minimum attained under lowest nutrient level 60:30:20 kg/ha of N:P:K under weedy check. The combination of 100:50:40 kg/ha of N:P:K along with pretilachlor750 g/ha fb bispyribac-Na 25 g/ha recorded maximum weed management index (5.11) and agronomic management index (4.11) at 60 DAS and higher gross returns ( 1,16928/ha), net returns ( 93376/ha) and B:C (3.13) as compared to rest of the treatment combinations.

Agronomic management index, Weed control efficiency, Weed indices, Weed management index, Weed persistence index

In central India, most of the arable and disturbed non-arable lands are vulnerable to invasions of field sowthistle (Sonchus oleraceus L.) during winter and summer. Its infestation has threatened the resident biodiversity and has also posed the possibility of spread to adjoining areas. The present study was conducted to know the biology of S. oleraceus, its impact and suggest suitable management strategies to restrict its further spread. In wheat, pendimethalin fb metsulfuron-methyl (678 fb 4 g/ha) recorded the lowest density and biomass of S. oleraceus (2 no./m2 and 0.5 g/m2, respectively) with 92.3% weed control efficiency (WCE) followed by clodinafop + metsulfuron (60+4 g/ha), which were statistically comparable. Similarly, in chickpea, pendimethalin + imazethapyr (900+60 g/ha) recorded the lowest density and biomass of S. oleraceus (3 no./m2 and 1.1 g/m2, respectively) with 86.9% WCE, where density was comparable to propaquizafop + imazethapyr (50+75 g/ha). The lower density of S. arvesnsis recorded with higher grain yield of wheat (5.10 t/ha) and seed yield of chickpea (2.25 t/ha). The highest density and least yield recorded in control plots.

Biology, Chickpea, Emergence, Impact and management, Sonchus arvesnsis, Wheat

Field experiment was conducted in naturally Striga hermonthica (Witchweed) infested field in the Kassena-Nankana East district of the upper East region, Ghana during the 2018 cropping season. This was to investigate effects of Striga tolerant pearl millet varieties intercropped with cowpea on S. hermonthica and crop yield. The study was done in a 4 x 3 factorial experiment consisting of four pearl millet varieties (Akad-kom, Kaanati, Naad-kohblug and Waapp-naara) and three cropping patterns (sole millet, millet-cowpea (1:1) and millet-cowpea (2:1) laid out in a randomized complete block design with three replications. Results showed that Striga emergence and shoot biomass was highest with Waapp-naara variety, which led to low grain yields (1.78 t/ha). Grain yield of Akad-kom (1.89 t/ha) was outstanding with millet-cowpea (1:1) as the best cropping pattern. Millet-cowpea (1:1) cropping pattern had the lowest Striga numbers and shoot biomass. Naad-kohblug variety and MC (1:1) cropping pattern gave best total LER of 1.44 and 1.41, respectively. Grain yield negatively correlated with Striga count (r = -0.42). Millet-cowpea (1:1) cropping pattern exhibited suicidal germination of Striga seeds, enhanced soil fertility and promoted Striga seed bank depletion of 46%. Resource poor farmers in Striga endemic areas could plant Akad-kom and Naad-kohblug varieties as sole crops or intercropped with cowpea (1:1) to manage Striga hermonthica and maximize grain yields.

Pearl millet varieties, Cowpea, Cropping systems, Intercrop, Striga hermonthica, Grain yield, Land equivalent ratio

Field experiments were conducted to evaluate the bio-efficacy and phyto-toxicity of sodium acifluorfen 16.5% + clodinafop-propargyl 8% EC as post-emergence against weed flora in groundnut during Kharif (rainy season) 2015 and summer 2016 at UAS, GKVK, Bengaluru, Karnataka. Different post-emergence herbicides were applied at 22 days after sowing (DAS) and compared with two rounds of hand weeding at 20 and 45 DAS. The results revealed that sodium acifluorfen 16.5% + clodinafop-propargyl 8% EC (206.25 + 80 g/ha) recorded higher pod (1.44 and 1.65 t/ha) and haulm yield (1.59 and 1.89 t/ha) in 2015 and 2016. Higher economic yield under this treatment was attributed to the reduced weed density, weed dry weight, weed index and higher weed control efficiency and higher herbicide efficiency index. Post-emergence application of sodium acifluorfen 16.5% + clodinafop-propargyl 8% EC was found non-phytotoxic to groundnut as well as succeeding crop (finger millet).

Clodinafop-propargyl, Groundnut, Sodium acifluorfen, Weed density, Yield

Field experiments were conducted at Tamil Nadu Rice Research Institute, Aduthurai, Thanjavur district, Tamil Nadu, India to evolve efficient and economic weed management practices for irrigated blackgram during Kharif (rainy season) 2018 and winter 2018-19. The results revealed that pre-emergence application of pendimethalin1.0 kg/ha on 3 DAS fb acifluorfen-sodium (16.5%) + clodinafop-propargyl (8% EC) 187.5 g/ha on 20 DAS effectively reduced weed density and dry matter production. Consequently, higher seed yields of 1.05 and 1.01 t/ha in the Kharif and winter seasons were recorded, respectively. The increase was 15.2, 78.7, and 9.2, 86.9% over hand weeding twice, unweeded check in Kharif and winter seasons, respectively. Among the treatment combinations, adoption of pendimethalin fb acifluorfen-sodium + clodinafop-propargyl on 20 DAS had highest gross return ( 64,234 and 72,383/ha), net return ( 37,374 and 44,722/ha) and B:C (2.39 and 2.62) during Kharif and winter seasons, respectively. Hence, this weed management practice could be a viable and cost effective in irrigated blackgram for enhancing production and productivity of blackgram.

Blackgram, Early post-emergencem, Pre-emergence, Nail weeder, Weed management

A field experiment was carried out at Agronomy Farm, College of Agriculture, Vellanikkara in, Kerala, India a randomized block design consisted of ten treatments having three replicates during the years 2019 to 2021 to develop a conservation agricultural practices for upland rice-vegetable-green manure cropping system. It has been found that different conservation treatments had a significant effect on weed density, weed dry matter production, weed control efficiency, yield and economics in okra (lady finger). The results revealed that the lowest density and dry matter of weeds were recorded in direct-seeded rice in flat bed + green manuring followed by okra with crop residue mulch at 30,60,90 DAS and at harvest. Highest weed control efficiency (59-67%) and yield (16.47 t/ha) in okra was registered in direct-seeded rice in flat bed + green manuring followed by okra with crop residue mulch. The highest weed density and weed dry matter production was noticed in direct-seeded rice in flat bed-okra. While considering the whole cropping system the highest B:C was found in direct-seeded rice in flat bed + green manuring followed by okra-green manure based cropping system (3.31).

Brown manuring, Crop residue mulch, Flat bed, Green manuring, Raised bed, Rice-okra cropping system

The noxious Kongwa weed (Astripomoea hyoscyamoides VatkeVerdc.) has been reported to cause enormous damage to crops and pastures in various parts of Tanzania, particularly Kongwa District of Tanzania. This paper assesses spread risk of potential pathways for the entry and spread of it in Kongwa District. The research progressed in two stages­ with the first stage comprising a review of relevant local and international literature on the means of weed spread. Secondly, a household survey using a semi-structured questionnaire was conducted in Kongwa district to collect data on various land use practices that are associated with the spreading of the weed. Risk assessment framework containing six criteria was applied to the identified potential pathways. Pathway risk for each pathway was evaluated and assigned an intensity rating score through an analysis of the interviewee answers using Statistical Package for the Social Sciences (SPSS) software version 26. Results showed that, the most high-risk pathways were livestock movements and stock fodder transportation (81%) and agricultural produce and inputs (77%) which was attributed to the existing land use type in Kongwa. The medium risk pathways were farming tools, equipment, machines, footwear and clothing (75%) and water dispersal (56%). The low-risk pathways were wind dispersal (44%), construction activities (43%), escape from research sites (30%), ornamental plant trade (28%), tourism (25%) and introduction via exotic plant species (20%). Based on these findings, government and other stakeholders are advised to allocate weed preventive resources in the order of the threat level posed by a particular pathway

Dissemination, Noxious Kongwa weed, Pathways, Pathway risk analysis, Risk assessment

The application of pesticides is one of the important aspects of a crop production system. The development of a single spraying system for all types of pesticide application is a solution for a cost-effective and efficient crop production system. Standardizing the droplet sizes at different operating pressure of hollow cone nozzle will be a solution for controlling the weeds as well as the other pests. A small tractor-operated hollow cone-based boom sprayer was developed to overcome said problems. The developed sprayer can be mounted on three-point linkage and can be operated by tractor PTO. The developed system was evaluated for 0.1, 0.2 and 0.3 MPa of operating pressure through water-sensitive papers and ImageJ software. Under this pressure, the selected hollow cone nozzle produced medium to coarser droplet size. The highest VMD of 346.4 µm was obtained under operating pressure of 0.1 MPa and the least VMD of 277.1 µm was obtained under operating pressure of 0.3 MPa. The increase in operating pressure causes a reduction in droplet size. However, the relative span (RS) was increasing with a decrease in operating pressure. It was 0.72 at an operating pressure of 0.3 MPa and increased to 1.27 at an operating pressure of 0.1 MPa. The highest weed control efficiency (WCE) of 88.1% was obtained under 0.1 MPa of operating pressure. However, the operating pressure does not had significant effect on WCE.

Boom sprayer, Hollow cone nozzle, Small tractor, Volume mean diameter, Weed control efficiency

The information on efficacy of new low-dose herbicides and herbicide mixtures is very limited in transplanted rice. An experiment was conducted, to study the effect of herbicides and herbicide mixtures on weed control in transplanted rice. Lower weed density and dry weight was recorded with florpyrauxifen-benzyl + cyhalofop-butyl and penoxsulam + cyhalofop-butyl which was at par with hand weeding at 20 and 40 DAT. Herbicide mixtures were more effective to control weeds than single application of either pre- or post-emergence herbicides. Higher grain and straw yields were obtained with florpyrauxifen-benzyl + cyhalofop-butyl EC 150 g/ha PoE fb hand weeding at 40 DAT which was comparable to minimum competitive plot. 

Herbicide mixtures, Transplanted rice, Weed control efficiency, Weed density, Weed dry-weight

Rumex spp. is the major broad-leaf weed of irrigated wheat. Manual weeding is not feasible in wheat crop sown with a narrow spacing and weed management thus is accomplished through application of herbicides. The poor efficacy of otherwise effective herbicides so far against this weed has come to the fore indicating the likelihood of herbicide resistance. Hence, the present study was carried out during Rabi of 2017-18 at screen house of College of Agriculture, Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana, India to evaluate herbicide resistance in Rumex spp. and its management in wheat crop using four test populations of Rumex spp. named as HHH (HAU Hisar), UPH (Ujha, Panipat), JHH (Jind), and JJR (Jhajjar). Three herbicides - carfentrazone, mesosulfuron + iodosulfuron and 2,4-D ester at three doses (0.5X, X and 2.0X) with one unsprayed control were taken as treatments in the pot experiment under completely randomised design (CRD) replicated thrice. Results indicated that all the populations have attained resistance against mesosulfuron + iodosulfuron even at double of the recommended dose. Higher values of plant height, chlorophyll fluorescence, dry weight and lower value of electrical conductivity was observed in mesosulfuron + iodosulfuron treated plants. Carfentrazone provided moderate control to all populations even at double of the recommended dose. The application of 2,4-D ester at double of the recommended doses provided 77-100% control of all populations except UPH where lower efficacy continued even at double dose. Resistance thus confirmed in Rumex dentatus requiring alternate herbicides for field level effective management.

2,4-D ester, Carfentrazone, Chlorophyll fluorescence, Mesosulfuron + iodosulfuron, Rumex spp.

A field experiment was conducted during the Rabi (winter) season of 2016-17 at Agricultural Farm, Institute of Agriculture, Visva-Bharati, Sriniketan, West Bengal to study the effect of tillage and weed management on weed growth, productivity and profitability of wheat. The experiment was laid out in a split-plot design with three replications comprising of two tillage and six weed management practices in main and sub plots, respectively. Results showed that zero tillage registered significantly lower density of grasses and total weeds as compared to conventional tillage. Among the weed management practices, weed free plot registered significantly higher grain yield (3.6 t/ha), which was statistically at par with the application of both the doses (25 and 35 g/ha) of sulfosulfuron ethyl + metsulfuron-methyl and clodinafop-propargyl + metsulfuron-methyl 96 g/ha. Zero tillage with the application of sulfosulfuron-ethyl 75% + metsulfuron-methyl 5% WG 35 g/ha fetched the highest net return ( 40,119/ha) and return per rupee invested (2.3), which was comparable with sulfosulfuron-ethyl 75% + metsulfuron-methyl 5% WG 25 g/ha. Thus, in late sown wheat, zero tillage along with pre-mix application of sulfosulfuron-ethyl 75% + metsulfuron-methyl 5% WG 25-35 g/ha and clodinafop-propargyl + metsulfuron-methyl 96 g/ha at 30 DAS appeared to be promising for effective weed control and higher productivity as well as profitability. 

Clodinafop + metsulfuron-methyl, Pre-mix, Sulfosulfuron + metsulfuron methyl, Wheat, Zero tillage

The field experiment was conducted during 2014-16 in Rabi (winter) season (October - December) at Agricultural Research station, Kovilpatti, Tamil Nadu, India. The treatment combinations comprised of three dates of seeding, viz. last week of September, 2nd week of October and last week of October in main plot with four weed management treatments, viz. pendimethalin 0.75 kg/ha pre-emergence application (PE) fb hand weeding (HW) on 20 days after seeding (DAS), pendimethalin 0.75 kg/ha PE fb quizalofop-ethyl 50 g/ha post-emergence application (PoE) on 20 DAS, pendimethalin 0.75 kg/ha PE fb imazethapyr 50 g/ha PoE on 20 DAS, imazethapyr 50 g/ha + quizalofop-ethyl 50 g/ha (tank mix) PoE at 20 DAS in the sub plot. The seeding during last week of September registered increased growth and yield parameters, viz. dry matter production (DMP), leaf area index (LAI), number of pods/plants, pod length, number of seeds/pods which reflected on increased grain yield (850 kg/ha). Among the weed management treatments, pendimethalin 0.75 kg/ha PE fb HW on 20 DAS recorded significantly lower weed density and weed biomass which in turn produced increased growth and yield attributes and yield of the crop which was followed by application of pendimethalin 0.75 kg/ha PE fb quizalofop-ethyl 50 g/ha PoE on 20 DAS.

Greengram, Growth, Herbicides, Seeding dates, Weed control, Yield 

A field experiment was conducted at Horticulture Polytechnic College, Navsari Agricultural University, Paria, Gujarat, India to determine the effect of mulching and herbicides on weed infestation, yield and economics of tomato cultivation under drip irrigation system. The experiment comprised of four mulches, viz., black polyethylene, silver polythene, red polythene and paddy straw; two herbicide treatments i.e. pendimethalin 1.0 kg/ha pre-emergence + one hand weeding at 45 days after transplanting (DAT), pendimethalin 1.0 kg/ha pre-emergence + quizalofop-p-ethyl 0.04 kg/ha post-emergence PoE at 45 DAT along with a weed free treatment and a weedy check. Results revealed that black polythene mulch recorded highest weed control efficiency (37.86%), minimum weed index (0.00%), highest yield (82.45 t/ha), maximum net realization and highest benefit cost ratio (2.20). Therefore, it is suggested that the black polythene (50 µ) mulching may be used for effective weed management and optimal yield of tomato under drip irrigation system.

Pendimethalin, Quizalofop-p-ethyl, Mulching, Tomato, Weed control efficiency

The present experiment was conducted to study the effect of different mulching materials and herbicide application on weed growth parameters, weed control efficiency (WCE) and corm yield in gladiolus variety ‘Punjab Glance’. The experiment was laid out in a randomized block design with three replications each using polythene mulches of colours, viz. black 25µ, silver on black 25µ, transparent 25µ and white 50 µ along with rice straw mulch at concentrations of 1.0 kg, 1.5 kg and 2.0 kg/m2 respectively. The predominant weeds observed were Oenothera laciniata, Coronopus didymus and Poa annua during November to March. The black and silver on black polythene mulch 25µ along with pendimethalin 0.5 kg/ha reported minimum total weed count, total weed fresh and dry weight. The hand-weeded plot showed maximum WCE (100%) followed by pendimethalin 0.5 kg/ha (99.9%) and similar results were recorded under black and silver on black polythene mulch 25µwith 99.8and 99.5% WCE respectively. The black polythene mulch 25µ best promoted plant growth in terms of corms per plant (1.8) cormels per plant (28.5) and corm weight (61.2 g). It suppressed the weeds efficiently with weed count of only (2.3/m2) from November to March.

Gladiolus, Integrated weed management, Mulch, Weed control efficiency

A field experiment was conducted under loamy sand soil during Kharif (rainy season), 2018 at Swami Keshwanand Rajasthan Agricultural University, Bikaner to evaluate the bio-efficacy of herbicides in clusterbean as affected by time of application. Results revealed that imazethapyr + imazamox at 50 g/ha as PoE (20 DAS) and pendimethalin + imazethapyr at 0.80 kg/ha as PE resulted in the lowest weed density and dry weight of both monocot and dicot weeds. Higher weed control efficiencies were also noted under these treatments. Plant height, pods per plant, seeds per pod and seed and straw yields, net returns and benefit: cost ratio were also superior with imazethapyr + imazamox at 50 g/ha as PoE (20 DAS) and pendimethalin + imazethapyr at 0.80 kg/ha as PE compared to the other treatments.

Clusterbean, Herbicide, Imazethapyr, Pendimethalin, Weed control

Ten weeds/wild plants belonging to six families, viz. Martynia annua, Cleome viscosa, Physalis minima, Cestrum diurnum, Amaranthus spinosus, Costus speciosus, Croton sparsiflorus, Datura metel, Solanum indicum and Solanum sisymbriifolium were recorded as the host plants of Ralstonia solanacearum from Sundanban region of West Bengal, India. Among them, Martynia annua and Cleome viscose were recorded first time from India. These weed hosts enable the survival of the bacterial pathogen in absence of crop hosts, and play a significant role in widespread incidence of bacterial wilt of cultivated vegetable crops in West Bengal.

Bacterial wilt, Ralstonia solanacearum, Sundarbans, Wild host, Weeds