Ai Ha Research Articles

Studies on Growth Characteristics of Hydrocarbon Producing Botryococus braunii

Two field experiments were conducted at Tamil Nadu AgriculturalUniversity, Coimbatore, Tamil Nadu to evaluate bioefficacy, phytotoxicityeffect if any of flupyradifurone 200 SL against whiteflies and leaf hoppersand its safety to non target invertebrates in brinjal during 2015 – 16. Theresults revealed that flupyradifurone 200 SL@ 175 g ai ha-1 was effective inreducing whiteflies and leaf hoppers population. The whiteflies per centreduction of 96.40 and 95.77 was obtained in first and second season,respectively. Similarly, regarding leaf hopper 96.35 and 97.92 per centreduction over control was recorded. The imposed treatments were foundsafer to non target invertebrates like spiders and coccinellids. Furthermore,no phytotoxic effect was observed even in treatments imposed withflupyradifurone 200 SL @ 75 and 150 g a.i. ha-1.

Broadleaf Weed Control with Halosulfuron Tankmixes in White Bean

Six field trials were conducted over a four-year (2017-2020) period near Exeter and Ridgetown, Ontario to determine the efficacy of halosulfuron tankmixes applied postemergence to control broadleaf weeds in white bean. Halosulfuron caused up to 4% injury in white bean at 2 and 4 weeks after treatment (WAT). Bentazon, acifluorfen, fomesafen, bentazon/acifluorfen, and bentazon + fomesafen caused 2% - 16% injury at 2 WAT and up to 3% injury at 4 WAT in white bean. The addition of halosulfuron to the aforementioned herbicides did not accentuate white bean injury. Reduced weed interference with the herbicides evaluated increased white been yield 50% - 90% compared to the weedy control; there was no difference in seed yield among herbicide treatments evaluated. At 4 WAT, halosulfuron at 25, 37.5 and 50 g ai ha-1 controlled velvetleaf 86%, 93% and 97%; redroot pigweed 83%, 85% and 89%; common ragweed 90%, 93% and 94%; common lambsquarters 27%, 28% and 36%; flower-of-an-hour 66%, 76% and 69%; and wild mustard 100%, 100% and 100%, respectively. Bentazon, acifluorfen, fomesafen, bentazon/acifluorfen, and bentazon + fomesafen controlled velvetleaf 73%, 14%, 52%, 42% and 68%; redroot pigweed 40%, 91%, 85%, 75% and 80%; common ragweed 36%, 81%, 92%, 68% and 84%; common lambsquarters 87%, 39%, 48%, 60% and 76%; flower-of-an-hour 90%, 66%, 63%, 73% and 83%; and wild mustard 97%, 97%, 100%, 99% and 100%, respectively. Halosulfuron tankmixed with bentazon, acifluorfen, fomesafen, bentazon/acifluorfen or bentazon + fomesafen controlled velvetleaf 90%, 51%, 68%, 75% and 90%; redroot pigweed 80%, 99%, 95%, 92% and 91%; common ragweed up to 94%, 97%, 93%, 94% and 95%; common lambsquarters 74%, 62%, 43%, 62% and 66%; flower-of-an-hour 92%, 78%, 74%, 82% and 87%; and wild mustard 100%, 100%, 100%, 100% and 100%, respectively. Weed density and dry biomass followed the same trend. This study concludes that the optimal halosulfuron tankmix is broadleaf weed species specific for weed management in dry bean production.

Trinexapac-ethyl as an Alternative to Reduce Lodging and Preserve Grain Yield and Quality of Rye

Trinexapac-ethyl (henceforth referred to as trinexapac) is a growth regulator that can mitigate some undesirable vegetative growth in Poaceae plants, reducing lodging and optimizing the distribution of photoassimilates to reproductive organs. The objective of this research was to evaluate the morphophysiological and productive responses of rye cultivars and trinexapac doses applied at different phenological stages of plants. Two field experiments were performed in two different seasons. In the 2015 growing season, 8 doses of trinexapac were evaluated: 0, 75, 85, 100, 115, 130, 150, 200 g ha-1 of active ingredient (a.i.), applied at the plant growth stage with the 4th node visible on the main stem (GS34). In the 2018 growing season, two cultivars (IPR 89 and BRS Serrano) and five doses of trinexapac were evaluated: 0, 50, 100, 150 and 200 g a.i. ha-1, applied at the plant growth stage with the 6th node visible on the main stem (GS36). The morphophysiological, productive and qualitative characteristics of grains were evaluated. In the 2015 season, trinexapac applied to shoot plants at GS34 only have low response in decreased plant lodging from around 20% to 10%. However, in the 2018 season, the application of trinexapac on plants at GS36, resulted in lower plant height, associated with reduced lodging and better quality of rye grains. Cultivar IPR 89 showed higher values for yield components and grain quality in comparison to cultivar BRS Serrano. Reduced lodging is dependent on speed of resumption of plant height growth, and the magnitude of response to trinexapac is also stage-cultivar-dose-dependent; in rye, the best response to trinexapac was found at GS 36 in comparison to GS 34, and for IPR 89 in comparison to BRS Serrano cultivar, respectively, with a dose range from 100 to 150 g ai ha-1. In conclusion, trinexapac (around 150 g a.i. ha-1), when applied to plants at GS36, reduces plant height, reduces the lodging index and enables the harvest of high-quality grains.

Reducing Grain Sorghum (Sorghum bicolor L. Moench) Injury From Postemergence Application of Mesotrione With Dicamba

Weed management in grain sorghum is limited by the number of herbicide options. A two-year (2017-2018) field study was conducted at the Mississippi State University Delta Research and Extension Center, in Stoneville, MS to evaluate the response of grain sorghum to mesotrione application alone or when tank-mixed with dicamba at the two-leaf and four-leaf growth stage of sorghum. Mesotrione was applied at 0.07 and 0.105 kg ai ha-1 alone or was tank-mixed with dicamba at 0.28 kg ae ha-1. Significant injury to grain sorghum from all herbicide treatments was observed compared with the untreated check. Increase in mesotrione application rate increased injury to grain sorghum from 14 to 19% at two-leaf and from 10 to 24% at the four-leaf stage by 4 weeks after application (WAA) in 2017. Adding dicamba to mesotrione reduced grain sorghum injury in both years. At 4-leaf sorghum application stage, mesotrione applied at 0.07 kg ha-1 resulted in greater grain yield than all other herbicide treatments, except mesotrione (0.105 kg ha-1) + NIS in 2017. Our results indicate that adding dicamba to mesotrione safes grain sorghum from injury caused by mesotrione alone.

Weed Dynamics in Maize (Zea mays L.) as Influenced by Pre and Post-emergence Herbicides under Temperate Conditions of Western Himalayan Region

Field experiments were conducted in 2017-18 during main cropping seasons of the year 2017 and 2018 at Dryland (Karewa) Agriculture Research Station, SKUAST-K to determine the effect of different post and pre emergence herbicides application on weed dynamics in maize (Zea mays L.). The experiment was laid out in randomized block design with four replications and variety used was Bio-605. Five treatments Five treatments viz, Atrazine 50% WP @ 1.0 kg ha-1 as pre-emergence and Paraquat dichloride 24% SL @ 0.5 kg ha-1, 2,4-D sodium salt 58% WSC @ 1.0 kg ha-1 as post-emergence herbicides (application at 2-3 leaf stage of weeds), hand weeding as standard check and weedy check as control were used. Effect of different herbicides on weed density was found significant. in plots managed with hand weeding, no weed was recorded. The Atrazine treated plots @ 1.0 kg ai ha-1 as pre-emergence had the weed population of 5.51, 5.4, 3.73, 5.12, 4.28 and 41.4m-2 , respectively in Echinochloa spp., Eleusine indica, Digitaria sanguinalis, Amaranthus viridis, Sorghum halepense and Cyperus spp. However, the maximum population of weeds was recorded in weedy check with 21.54 m-2, 20.87 m-2, 19.16 m-2, 21.5 m-2, 16.7 m-2 and 60.7 m-2. No significant difference was observed between Paraquat dichloride 24% SL @ 0.5 kg ai ha-1 and 2,4- D Sodium salt 58% WSC @ 1.0 kg ai ha-1 except for Cyperus spp. with density of 51.37 m-2 and 43.04 m-2 respectively. The potential of the atrazine in controlling weeds thereby enhancing yield of maize was found in this study.

Eficácia do herbicida flumioxazin no controle de Euphorbia heterophylla, na aplicação sobre diferentes tipos de palha e simulações de chuva: Controle de Euphorbia heterophylla com flumioxazin

In the spread of pre-emergent herbicides on straw, the type and quantity of this material and the physical-chemical characteristics of the herbicides, are decisive in the effectiveness of weed control. The objective of this work was to evaluate the efficacy of the flumioxazin herbicide in the pre-emergence control of the weed Euphorbia heterophylla L., when applied over different straw management and rain simulations. The experimental design was completely randomized, with four replications, organized in a 7x3 factorial scheme, with seven straw managements (without straw; B. ruziziensis with 3t ha-1 and 5t ha-1; B. ruziziensis+Z. mays with 3t ha-1 and 5t ha-1; Z. mays with 3t ha-1 and 5t ha-1) and three amounts of rain (10, 25 and 40mm) and the herbicide flumioxazim(120g ai ha-1). The control evaluation was carried out at 7, 14, 21, 28, 35 and 45 days after emergence(DAE) and at 45 DAE the dry mass of the aerial part. The highest percentages of control occurred in the application of flumioxazin on Brachiaria ruziziensis 3t ha-1 and 5t ha-1 and Zea mays 3t ha-1, with 86.25, 82.08 and 80.41% respectively. The 10 mm rain resulted in the lowest percentage of control of Euphorbia heterophylla. Thus, the type of straw and its quantity interfere in the control effectiveness.

Determination of The Efficacy of Some Herbicides on the Weeds in Safflower

Safflower is a conspicuous energy crop might be used as a biofuel and raw material source for vegetable oil and animal feed sectors. It has a potential to reduce energy and oil dependency of Turkey reached to a high level due to its capacity. Weeds can cause yield loss because they compete with the crop for water, light, space, and nutrients in safflower. Weed control practices, therefore, should be made efficiently to gain high safflower yield. The aim of this study is to determine the efficacy of pendimethalin, s-metolachlor, and chlorsulfuron to control weeds and the response of safflower to them. The field experiments were conducted during 2017-2019 in Gölbaşı, Ankara, Turkey. Pendimethalin and s-metolachlor were applied to the soil surface before crop sowing at 675.0, 1012.5, 1350 and 2700, and 686.25, 915.0, 1372.5 and 2745.0 g active ingredient (ai) ha-1, respectively. Chlorsulfuron was treated at 3.75, 4.95, 5.625, 7.5 and 15.0 g ai ha-1 to the weeds when they were 2-4 true leaf stage. Responses of safflower to the herbicides and the efficacy of these herbicides on the weed were visually evaluated 14 and 28 days after treatment (DAT) and before the harvest. Pendimethalin caused very slight crop injury, and the symptoms were disappeared at 28 DAT in 2017, but same symptoms were not observed in 2018. The crop injury caused by chlorsulfuron was transient when it was applied lower than at 5.625 g ai ha-1; however, chlorsulfuron at 7.5 and 15 g ai ha-1 injured persistently safflower plants. Pendimethalin provided moderate control on wild mustard and redroot pigweed at 1350 g ai ha-1 while s-metolachlor at 1372.5 g ai ha-1 sufficiently controlled redroot pigweeds, but not wild mustard. Weed control with chlorsulfuron at higher than 4.95 g ai ha-1 was good compared to lower rates.

Effect of weed management practices on transplanted finger millet (Eleusine coracana L.) in Bihar

A field experiment was conducted at Research Farmland, Bihar Agricultural University, Sabour, Bhagalpur, Bihar during kharif season of 2019 to evaluate weed management practices in transplanted finger millet. The experiment was laid out in randomized block design with three replication and consisting eleven treatment viz., T1 (Weedy check), T2 (Hoeing at 20 and 40 DAT), T3 (Pendimethalin @ 750 g ai ha-1 as pre-emergence), T4 (2, 4- D @ 750 g ai ha-1 as post-emergence), T5 (Bispyribac sodium @ 20 g ai ha-1 as post-emergence), T6 (Pendimethalin @ 750 g ai ha-1 as pre-emergence fb 2, 4-D @ 750 g ai ha-1 as post-emergence), T7 (Pendimethalin @750 g ai ha-1 as pre-emergence fb Bispyribac sodium @ 20 g ai ha-1 as post-emergence), T8 (Pretilachlor @1000 g ai ha-1 as pre-emergence), T9 (Pretilachlor @1000 g ai ha-1 as pre-emergence fb 2, 4- D @ 750 g ai ha-1 as post- emergence), T10 (Pretilachlor @1000 g ai ha-1 as pre- emergence fb Bispyribac sodium @ 20 g ai ha-1 as post- emergence) and T11 (weed free). The results revealed that sequential application of Pretilachlor @1000 g / Pendimethalin @750 g ai ha-1 as pre-em fb Bispyribac sodium @ 20 g ai ha-1 as post-emergence for higher yield, net return and B:C ratio of transplanted finger millet in Bihar.

INTERVAL BETWEEN SEQUENTIAL HERBICIDE TREATMENTS FOR SOURGRASS MANAGEMENT

ABSTRACT More than one herbicide application is usually necessary to manage glyphosate-resistant sourgrass in advanced stages of development efficiently during off-season fallow periods. The objective of this study was to determine the best interval between two sequential applications to control sourgrass, based on the number of days and tiller-height after the first treatment. Two experiments were conducted based on these criteria. Experiment 1 consisted of one application of glyphosate + clethodim (1140 ae ha-1 + 108 g ha-1) followed by glyphosate + clethodim or paraquat (400 g ai ha-1) at an interval of 10, 17, 24, 31, 28, or 45 days. Experiment 2 was conducted with the same herbicide treatments, but using the tiller-height as the criteria for the second application, which were 2-5, 6-10, 11-20, 21-30, and >30 cm. None of the treatments resulted in total sourgrass control during the evaluation period. Overall, treatments with glyphosate + clethodim in the second application were more efficient than paraquat. The most effective interval between sequential applications of glyphosate + clethodim was observed at 17 to 24 days. For paraquat, the best interval for the second application was 6-10 days. The most effective performances based on the tiller-height were found at 620 cm tall for glyphosate + clethodim and 6-10 cm tall for paraquat.

Southern Sandbur (Cenchrus echinatus L.) Control in Bermudagrass Pastures with Indaziflam Herbicide Systems

Field studies were conducted during 2019 growing season in north-central, south-central, and the Coastal Bend areas of Texas to evaluate indaziflam herbicide systems for southern sandbur control and Coastal bermudagrass tolerance. Indaziflam caused no bermudagrass stunting at any location when applied preemergence (PRE) at 0.04 to 0.07 kg ai ha-1. Glyphosate at 0.35 kg ae ha-1 caused bermudagrass stunting which ranged from 16 to 65% when evaluated 3 to 5 weeks after application; however, when evaluated at the end of the growing season, no bermudagrass stunting was evident when compared with the untreated check. Southern sandbur control with indaziflam, when evaluated 28 to 32 weeks after the initial indaziflam PRE application, ranged from 85 to 99% in north-central Texas, 65 to 95% in south-central Texas, and 95 to 100% in the Coastal Bend region. Southern sandbur control with pendimethalin PRE system ranged from 74 to 100%, 11 to 85%, and 100% in those regions, respectively. Indaziflam represents a safe option for forage and hay producers in Texas to control southern sandbur.

Use of the Premix of Atrazine, Bicyclopyrone, S-Metolachlor, and Mesotrione for Weed Control in Corn (Zea mays L.)

Field studies were conducted under conventional tillage from 2014 through the 2018 growing seasons in central, south-central, and the Panhandle regions of Texas to determine corn tolerance and weed efficacy of the four-way premix of atrazine plus bicyclopyrone plus mesotrione plus S-metolachlor (hereafter referred to as ABMS). No corn injury was noted at any location with any ABMS dose or application timing. Preemergence (PRE) applications of ABMS at 2.41 kg ha-1 controlled Palmer amaranth (Amaranthus palmeri S. Wats.) 73 to 100% while smellmelon (Cucumis melo L.) control was 100%. Annual sunflower (Helianthus annuus L.) control with ABMS at 2.41 kg ha-1 was 86% while a split application applied PRE followed by a postemergence (POST) application provided 99% control. Texas millet (Urochloa texana Buckl.) control with ABMS applied PRE ranged from 12 to 35% while broadleaf signalgrass (Brachiaria platyphylla [Griseb.] Nash) control was 100%. Browntop panicum [Urochloa fasciculate (Sw.) R. Webster] control with a PRE application of ABMS at 2.41 kg ai ha-1 was < 82% while jungle rice [Echinochloa colona (L.) Link] control was 98%. Control of a kochia (Kochia scoparia L.) with PRE applications of ABMS at 2.41 kg ha-1 was 95% while the split rate of 1.2 kg ha-1 applied PRE and POST provided 99% control. Corn yields were variable but in most instances all herbicide treatments improved yield over the untreated check. Excellent control of broadleaf weeds was observed with ABMS; however, annual grass control can be variable, especially with large-seeded annual grasses such as Texas millet.

INTERFERENCE OF SOIL COMPACTION ON DICLOSULAM RESIDUAL

O residual do herbicida no solo pode ser influenciado por diversos fatores incluindo a compactação do solo. O objetivo foi avaliar a influência dos níveis de compactação do solo na seletividade do herbicida diclosulam para a soja e efeito carryover no milho semeado em sucessão. O delineamento foi em blocos casualizados com 4 repetições. Os tratamentos em esquema fatorial 3x3, o fator A compactação (0, 10 e 20%) e o fator B as doses do herbicida diclosulam (0; 25.2 e 50.4 g i.a. ha-1) aplicado em pré-emergência. Após 90 dias da semeadura da soja, foi realizada coleta das plantas, abertura das colunas e semeados milho e pepino. Foram realizadas na soja as análises: fluorescência da clorofila a, massa seca da parte aérea (MSPA) e conteúdo de NPK das folhas aos 90 dias após a germinação (DAG). Para milho: fluorescência da clorofila a aos 15, 30 e 45 DAG. Para milho e pepino: estatura de plantas, comprimento das raízes, MSPA e massa seca da raiz aos 45DAG. A quantificação do resíduo do diclosulam por LC-MS/MS foi realizada aos 94 dias após aplicação do herbicida. Os dados foram submetidos à ANOVA (p ≤ 0,05) e comparadas pelo teste de Tukey a 5%. A soja em ambos os solos, não apresentou diferença nos parâmetros de crescimento e conteúdo de NPK, porém houve prejuízo nos parâmetros fotossintéticos. Não houve carryover causado a cultura do milho, independente da compactação do solo. Houve redução das plantas de pepino sendo agravado em solos compactados. Não foi detectado resíduo do diclosulam nos solos avaliados por LC-MS/MS.

Using Fluridone Herbicide Systems for Weed Control in Texas Cotton (Gossypium Hirsutum L.)

Studies were conducted during 2015 through 2018 in south-central, Coastal Bend, and Southern High Plains areas of Texas to evaluate fluridone herbicide systems for weed control and cotton response. Fluridone alone at 0.17 to 0.23 kg ai ha-1 followed by postemergence (POST) herbicides controlled Amaranthus Palmeri 82 to 100% season-long while Cucumis melo control ranged from 92 to 100%. Control of Urochloa Texana with fluridone alone ranged from 40 to 96% early-season while late-season control ranged from 37 to 96%. Fluridone plus fomesafen systems controlled A. Palmeri, C. Melo, and U. Texana at least 98% early season; however, late-season control of A. Palmeri was less than 70% while C. Melo control was 91% and U. Texana control was 80%. Adding a POST application of glyphosate to fluridone plus fomesafen improved control to at least 98% for all three weed species. Fluridone plus fluometuron combinations provided similar control to fluridone plus fomesafen. Adding glyphosate (POST) improved A. Palmeri control to at least 82% season-long. Cotton yields reflect the level of weed control with significantly better yields from fluridone systems compared with the weedy check. However, in the one year when the untreated was maintained weed-free, no differences in cotton yield were noted between the weed-free and any herbicide treatment.

Behavior of Five Sulfonylurea Herbicides and a Low-Dose Glyphosate on Cynodon nlemfuensis Pasture

African star grass (Cynodon nlemfuensis Vanderyst) is an excellent forage for animal feed, especially in tropical and subtropical climates. However, there is little information on weed management in African star grass pastures. Two experiments were carried out in 2017 and 2018 to evaluate the response of African star grass to five herbicides of the sulfonylureas chemical group and glyphosate at a low dose. The treatments were as follows: metsulfuron-methyl (Ally®) (7.8 and 15.6 g ai ha-1 plus 0.1% v/v mineral oil); chlorimuron-ethyl (Staron®) (15.0 and 30.0 g ai ha-1 plus 0.05% v/v mineral oil); halosulfuron (Sempra ®) (112.5 and 225.0 g ai ha-1 plus 0.1% v/v surfactant); ethoxysulfuron (Gladium®) (150.0 and 300.0 g ai ha-1); nicosulfuron (Sanson®) (60.0 and 120.0 g ai ha-1); glyphosate (Roundup Original®) (360 g ae ha-1); and a control without herbicide application. The herbicides nicosulfuron (60.0 and 120.0 g ai ha-1) and glyphosate were the most phytotoxic treatments; however, none of the treatments caused the total death of African star grass plants. The herbicides metsulfuron-methyl, chlorimuron-ethyl, halosulfuron and ethoxysulfuron were selective and are potential products for use in African star grass pastures.

Response of Soil Applied Herbicides at Different Application Timings on The Weed Control Efficacy and Phytotoxicity to Rice In Dry-seeded Condition

Dry-seeded rice (DSR) is a labor and water saving emerging production system. The use of pre-emergence herbicides was found to be the most effective weeds control measure under the DSR system. Although several herbicides are now available in market, the selection of right herbicides with a time of application is crucial for effective control of weeds as well as to reduce the phyto toxicity of crops. A field study in a split-plot design with three replications was conducted to evaluate the effect of application time of soil applied herbicides (viz., 3 times - before crop sowing, after crop sowing but before the first irrigation, and after sowing and first irrigation) and four weeding regimes (viz., weed free, partial-weedy, herbicide oxadiargyl 80 g ai ha-1, and pendimethalin 1000 g ai ha-1) on weed control efficacy, crop performance as well as phytotoxicity of applied herbicides under DSR system. Rice plant stand establishment was highly influenced by application time of herbicides and weeding regimes. Application of pendimethalin at 1000 g ai ha-1 significantly reduced the density of rice plant, more so as sowing was advanced. Compared with the non-treated (partial-weedy) treatment (190 to 195 rice plants m-2), pendimethalin application before sowing, after sowing but before irrigation, and after sowing and irrigation reduced rice plant density by 48, 25 and 12%, respectively. While no significant difference was observed on plant density due to the application of oxadiargyl 80 g ai ha-1, regardless of application time. In case of weed control efficacy for individual herbicides, pendimethalin effectively controlled weeds even spraying before sowing and irrigation; but comparatively less effective than spraying after irrigation. In controlling weeds, oxadiargyl was only effective when spraying after sowing and irrigation, but not before irrigation. Grain yield was significantly increased as the time of herbicide was delayed from before sowing (2.2-2.4 t ha-1), after sowing but before irrigation (2.5-2.6 t ha-1), and after sowing and irrigation (4.0-4.1 tha-1). The results suggest that pre-emergence herbicides should be applied after sowing and irrigation for controlling weeds effectively and also reduce crop toxicity under the DSR system.
 Bangladesh Agron. J. 2019, 22(1): 15-25

Weed Management in White Beans with Soil-Applied Grass Herbicides plus Halosulfuron

There are a limited number of soil-applied herbicides available for broad-spectrum weed control in dry bean production in Ontario, Canada. Four experiments were conducted from 2017 to 2019 in southwestern Ontario to compare the efficacy of six soil-applied grass herbicides [trifluralin (600 g ai ha-1), ethalfluralin (810 g ai ha-1), pendimethalin (1080 g ai ha-1), S-metolachlor (1050 g ai ha-1), dimethenamid-p (544 g ai ha-1) and EPTC (3400 g ai ha-1)] and halosulfuron (35 g ai ha-1) applied alone and in combination, applied preplant incorporated (PPI), on white bean tolerance and yield, and weed control efficacy. There was no white bean injury from the herbicide treatments evaluated. Grass herbicides (trifluralin, ethalfluralin, pendimethalin, S-metolachlor dimethenamid-P and EPTC) controlled velvetleaf 0% - 82%, pigweeds 87% - 99%, common ragweed 0% - 93%, common lambsquarters 81% - 99%, wild mustard 0% - 71%, barnyardgrass 98% - 100% and green foxtail 98% - 99%. Halosulfuron controlled velvetleaf 98%, pigweeds 94%, common ragweed 90% - 94%, common lambsquarters 97%, wild mustard 98% - 100%, barnyardgrass 19% - 24% and green foxtail 20% - 25%. Tankmixes of halosulfuron with soil-applied grass herbicides provided ≥93% control of the weed species evaluated. Reduction in density and biomass generally followed the same trend as visible control with herbicide treatments evaluated. Weed interference reduced white bean seed yield 70%. Seed yield was 53% - 66% of the weed-free control with trifluralin, ethalfluralin, pendimethalin, S-metolachlor and dimethenamid-P, 81% of the weed-free control with EPTC, 58% of the weed-free control with halosulfuron, and 87% - 95% of the weed-free control with halosulfuron tankmixes with the grass herbicides evaluated. Based on these results, halosulfuron in combination with trifluralin, ethalfluralin, pendimethalin, S-metolachlor, dimethenamid-p and EPTC, applied PPI at rates evaluated, can be used to effectively control common annual grass and broadleaf weeds in white beans.

Glyphosate-Resistant Canada Fleabane Control with Three-Way Herbicide Tankmixes in Soybean

Eight field trials (2 in 2016, 3 in 2017, 3 in 2018) were conducted in farmers’ fields with heavy infestations of GR Conyza canadensis (Canada fleabane, horseweed or marestail) to evaluate glyphosate (900 g ae ha-1) plus saflufenacil (25 g ai ha-1), 2,4-D ester (500 g ai ha-1) or paraquat (1100 g ai ha-1) applied preplant (PP) as 2-way tankmixes, or in 3-way tankmixes with sulfentrazone (140 g ai ha-1), flumioxazin (107 g ai ha-1) or metribuzin (400 g ai ha-1) for the glyphosate-resistant (GR) C. canadensis control in GR soybean. Glyphosate plus saflufenacil applied PP controlled GR C. canadensis as much as 90%. The addition of sulfentrazone, flumioxazin or metribuzin to the tankmix provided as much as 93%, 96% and 97% control of GR C. canadensis, respectively. Glyphosate plus 2,4-D ester applied PP provided as much as 59% control of GR C. canadensis. The addition of sulfentrazone, flumioxazin or metribuzin to the tankmix provided as much as 60%, 59% and 91% control of GR C. canadensis, respectively. Glyphosate plus paraquat applied PP provided as much as 85% control of GR C. canadensis. The addition of sulfentrazone, flumioxazin or metribuzin to the tankmix provided as much as 88%, 89% and 98% control of GR C. canadensis, respectively. Density and biomass reductions of GR C. canadensis with herbicides evaluated followed the same pattern as weed control evaluations. GR C. canadensis interference reduced soybean yield 66%. Reduced GR C. canadensis interference with the preplant herbicides evaluated provided soybean yield similar to the weed-free control. Results from this study show that glyphosate plus saflufenacil, glyphosate plus 2,4-D ester or glyphosate plus paraquat tankmixed with metribuzin can provide effective control of GR C. canadensis in GR soybean.

Persistence and dissipation behaviour of fipronil and its metabolites in sugarcane grown soil of South Gujarat

A field experiment was conducted at Main Sugarcane Research Station, Navsari Agricultural University, Navsari to study the dissipation behaviour of fipronil and its metabolites in sugarcane grown soil. The fipronil 0.3 GR was applied at standard and double dose i.e. 100 and 200 g ai ha-1 in gross plot when sugarcane crop was four month old. The soil sampling was done at 0 (2 hrs.), 1, 3, 5, 10, 20, 30, 60 and90 days after application of fipronil. In method verification, acetonitrile based extraction and dispersive clean-up approach adopted to quantify the residues of fipronil and its metabolites with gas chromatography (GC-ECD) from soil was accurate, precise and sensitive enough. Persistence study indicated that residues of fipronil progressively dissipated and reached BQL (

Weed management practices in direct seeded rice ecosystem in north western zone of Tamil Nadu

Field experiments were conducted to study the cost effective weed management practices in direct seeded rice at Regional Research Station, Tamil Nadu Agricultural University, Paiyur 635 112, Tamil Nadu, India in wet and dry seasons of 2015 and 2016 respectively in randomized block design with four replications. The treatments are pre- emergence application of Pendimethalin @ 1.0 kg ai ha-1 at 8 DAS followed by hand weeding at 25 DAS (T1 ), pre- emergence application of Pendimethalin @ 1.0 kg ai ha-1 at 8 DAS followed by post emergence application of Bispyribac sodium 25 g ha-1 at 25 DAS+ hand weeding at 45 DAS (T2 ) and Cono weeder weeding at 10 and 25 DAS (T3 ), Hand weeding on 15 and 30 DAS (T4 ) and Control - Weedy check (T5 ). The results revealed that, among the different weed control treatments, application of pre-emergence herbicide pendimethalin 1.0 kg ai ha-1 at 8 DAS with POE Bispyribac sodium 25g ha-1 at 25 DAS and HW on 45 DAS (T2 ) recorded higher grain yield of 6438 kg ha-1 with the B:C ratio of 2.77. With respect to weed control efficiency, application of pre-emergence herbicide pendimethalin 1.0 kg ai ha-1 at 8 DAS with POE Bispyribac sodium 25g ha-1 at 25 DAS and HW on 45 DAS (T2 ) recorded higher weed control efficiency of 81.0 % as compared with Cono weeder weeding at 10 and 25 DAS. Hence, it was concluded that considering the weed control efficiency, yield and economics, pre-emergence application of pendimethalin 1.0 kg ai ha-1 at 8 DAS with POE Bispyribac sodium 25g ha-1 at 25 DAS and HW on 45 DAS is recommended for weed management in direct seeded puddled rice to meet the challenges against labour scarcity and weed infestation in the field of small and marginal farmers.

Weeds found associated with wheat crop at Alahan Panjang, West Sumatra

Crop production is of major supports for ever-growing population. As for other crops, wheat cannot escape from weed interference which may result in significant loss of yield. Therefore, the success of agricultural practices depends on pest and diseases management including weeds. Agricultural chemicals such as herbicides has been widely applied to maximize crop yield including wheat. The present study was conducted to determine the appropriate herbicide to control weeds associated with wheat and wheat growth and yield. The experiment was carried out at farmer’s land at Batu Bagiriek, Jorong Galagah, Kenagarian Alahan Panjang, Solok, the Province of West Sumatra from May to September 2015. The experimental sites is located at 1.0729° S, 100.7831° E, 1616 m above sea level with temperature ranging from 20 to 25 °C. Three treatments i.e herbicide metsulfuron-methyl (25 g ai ha-1), herbicide 2,4 dimethylamine (1.5 L ai ha-1), and no weed control treatment were studied. Each treatment was replicated four times in a completely randomized design. Data were analysed with ANOVA and mean separation of Tukey HSD at 5%. Results demonstrate that herbicide 2,4 dimethylamine was best to control broad leaf weeds resulted in the highest yield of wheat grain of 6.14 tonnes/ha. Lawn grass (Axonopus compressus) and goose grass (Eleusine indica) were found to be dominant weeds.