Preemergence Applications Of Imazethapyr Research Articles

Efficacy of New Generation Herbicides in Soybean (Glycine max. L)

A field experiment was conducted at Agricultural Research Station, Adilabad, Telangana during Kharif, 2022 to assess the efficacy of new generation herbicides in soybean (Glycine max. L). The experiment was laid out in randomized block design with 11 treatments and replicated thrice. Results revealed that among herbicidal treatments, pre-emergence application of Diclosulam 84% WDG @ 26 g ha-1fb post-emergence of Fluazifop-p-butyl 11.1% w/w + Fomesafen 11.1% w/w SL @ 250 g ha-1 recorded lowest weed density, biomass, weed index and higher weed control efficiency, seed and haulm yield. It was followed by pre-emergence application of Imazethapyr 2% EC + Pendimethalin 30% EC mix @ 960 g ha-1fb post-emergence Fluazifop-p-butyl 11.1% w/w + Fomesafen 11.1% w/w SL @ 250 g ha-1.

Weed Management in Clusterbean under the Application of Different Agrochemicals and Phosphorus Levels

Among the Kharif legumes clusterbean (Cyamopsis tetragonoloba L. Taub) is important crop and popularly known as “Guar” in India. A field experiment was conducted during Kharif 2013 at Agronomy Farm, S.K.N. College of Agriculture, Jobner, Jaipur (Rajasthan) to evaluate the weed management in clusterbean under the application of different agrochemicals and phosphorus levels. The treatments comprising 6 weed control treatments (Weedy check, one hand weeding at 20 DAS, two hand weeding at 20 and 40 DAS, pendimethalin at 0.75 kg/ha, imazethapyr at 100 g/ha and fenoxoprop-p-ethyl at 70 g/ha and four levels of phosphorus (0, 20, 40 and 60 kg/ha) assigned to main and sub plots of spilt plot design, respectively and replicated thrice. Results showed that HW twice at 20 and 40 DAS and pre emergence application of imazethapyr at 100 g/ha resulted significant reduction in weed density and weed dry matter in comparison to most of the treatments. Results further indicated that application of 60 kg P2O5/ha in clusterbean recorded the highest density and dry weight of weeds at all the stages. Maximum weed control efficiency was recorded under two hand weeding at 20 & 40 DAS.

Effect of pre- and post-emergence herbicides on growth and nutrient uptake of weeds in urdbean (Vigna mungo) crop under Shivalik foothills plains of Jammu

A field study was conducted during the summer seasons of 2015 and 2016 at the Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Chatha, Jammu and Kashmir, to study the effect of pre- and post-emergence application of herbicides on nutrients uptake by weeds and blackgram or urdbean [Vigna mungo (L.) Hepper] crop. A significant reduction in weed density and weed biomass was observed with 2 hoeing. Further, among the herbicidal treatments, imazethapyr + pendimethalin @ 1,000 g/ha as pre-emergence and imazethapyr + imazamox 80 g/ha as post-emergence significantly reduced the weed density and weed biomass. The lowest nutrient depletion by weeds, highest grain and stover yields and nutrient uptake by urdbean crop were recorded with pre- emergence application of imazethapyr + pendimethalin @ 1,000 g/ha. Thus, pre-emergence application of imazethapyr + pendimethalin @ 1,000 g/ha may be used for effective weed-management for achieving the higher seed yield (786 kg/ha and 743 kg/ha) in urdbean crop, as it provided higher net returns of (`45,205/ha and 41,364/ ha) and benefit: cost ratio of (2.56 and 2.29) to resourceful farmers of sub-tropical conditions of Jammu region.

Impact of integrated weed management practices soil microbial count and grain yield in black gram (Phaseolus mungo L.)

A field investigation was carried out during Kharif season in 2010 at Agronomy Department Farm, Dr.Panjabrao Deshmukh Krishi Vidyapeeth, Akola, to evaluate the effect of four herbicides (imazethapyr, pendimethalin, fenoxyprop-p-ethyl and quizalofop -p-ethyl ) applied at different rates with different time of application (pre-emergence,post emergence and combination of both) and cultural practices on soil microflora and yield of black gram (Phaseolus mungo). Data revealed that different chemicals and cultural weed control practices were exhibited their superiority over weedy check and reduced the crop weed competition by controlling the annual and broad leaved weeds. Among all the weed control treatments, pre-emergence application of pendimethalin @ 1.5 kg/ha showed higher yield per ha (10.05) and in case of in microbial study, bacterial, fungal and actinomycetes count before spraying of herbicide was non-significant but microbial count was reduced after spraying of herbicides as compared to before spraying of herbicides,as a result(before and after spraying of herbicide) pre-emergence application of imazethapyr at 75 g ha-1[(25.11, 17.10 ) ,( 19.50, 10.84) and (22.30,16.10)] showed the lower microbial count. In case of weedy check(26.90, 20.60 and 23.98) showed maximum microbial count followed by weed free (26.50, 20.30 and 22.60 ), among all the weed control practices.

Impact of imazethapyr and its ready-mix combination with imazamoxto control weeds in blackgram

The bio-efficiency of imazethapyr and its combination with imazamox or pendimethalin in comparison to hand weeding against weeds, their effect on growth, yield and phytotoxicity on black gram and residual effect on succeeding mustard crop were studied during 2014–15 and 2015–16. Hand weeding twice resulted in the highest overall weed control efficiency followed by pre-emergence application of imazethapyr + imazamox 80 g/ha, preemergence imazethapyr + imazamox 70 g/ha and pre-emergence imazethapyr + pendimethalin 1000 g/ha. Hand weeding twice and pre-emergence imazethapyr + pendimethalin 1000 g/ha were comparable to pre-emergence imazethapyr + imazamox 70 g/ha for seed yield. With every increase of one weed per square metre, the blackgram seed yield was reduced by 2.1 kg/ha. Similarly with every g/m2 increase in weed weight, the blackgram yield was subjected to fall by 5.1 kg/ha. The economic threshold levels i.e. No/m2 and g/m2 with the weed management practices studied varied between 8.3–42.0/m2 and 3.5–17.6 g/m2. Weed persistence index (WPI) was lowest and crop resistance index (CRI) was highest in the hand weeding twice treatment. Post-emergence application of imazethapyr 70 and 80 g/ha and imazethapyr + imazamox 70 and 80 g/ha caused mild toxicity during 2014 and had therefore lower crop resistance index. Efficiency index was the highest under hand weeding followed by preemergence application of imazethapyr + imazamox 80 g/ha, pre-emergence imazethapyr + pendimethalin 1000 g/ha and pre-emergence imazethapyr 80 g/ha. Weed index indicated 55.4% reduction in yield of blackgram due to weeds. Preemergence imazethapyr 80 g/ha, imazethapyr + imazamox 80 g/ha, imazethapyr 70 g/ha and imazethapyr + pendimethalin 1000 g/ha had higher overall impact index than hand weeding due to lower cost. Residual effect/phytotoxicity was not observed on succeeding crop of mustard during 2014 and 2015 as well.

Response of weed management practices on the Productivity of urdbean (Vigna mungo L. Hepper)

A field Investigation was carried out to evaluate the effect of hand weedings and herbicides on the weed flora, growth and yield of urdbean (Vigna mungo). The experiment was conducted during kharif season 2011 in loamy sand soil, to study the effect of different Ten weed management treatments comprising weedy check, weed free, one hand weeding (HW) at 20 days after sowing (DAS), two HW at 20 and 40 DAS, trifluralin at 0.75 kg/ha, alachlor at 1.5 kg/ha, imazethapyr at 0.10 kg/ha, trifluralin at 0.75 kg/ha + HW at 30 DAS, alachlor at 1.5 kg/ha + HWat 30 DAS and imazethapyr at 0.10 kg/ha + HW at 30 DAS on urdbean. Results showed that the maximum plant height was recorded under weed free treatment at all the growth stages and the maximum dry matter accumulation of 108.88 and 159.31 g per metre row length at 50 DAS and harvest stages was obtained under imazethapyr at 0.10 kg/ha + HW at 30 DAS treatment that was significantly higher by 17.8, 21.8, 24.6, 31.8 and 56.0 per cent at 50 DAS and 20.4, 17.6, 25.4, 29.0 and 50.1 per cent at harvest stage over imazethapyr at 0.10 kg/ha, one HW at 20 DAS, alachlor at 1.5 kg/ha, trifluralin at 0.75 kg/ha and weedy check treatments, respectively.. Application pre emergence application of imazethapyr at 0.10 kg/ha + HW at 30 DAS was found the most effective treatment with regard of grain yield (1403 kg/ha) and net returns (Rs 34815/ha). Two hand weedings done at 20 and 40 DAS also produced grain yield of 1392 kg/ha with net returns of Rs 33469 /ha.

Effect of weed management practices on yield, weed control efficiency, weed index and economics in summer groundnut (Arachis hypogaea L.)

A field experiment was conducted during summer 2009 under irrigation on weed management practices in summer groundnut (Arachis hypogaea L.). The experiment was conducted at the College of Agriculture and Zonal Agricultural Research Station farm, Shimoga, Karnataka, India. Recommend cultural practices recorded a higher pod yield (2880 kg ha-1), which was statistically in par (p>0.05) with pre-emergence application of imazethapyr at 100 g a. i. ha-1 (2791 kg ha-1). Application of herbicides recorded a higher weed control efficiency compared to farmer’s practice and weedy check. Among the herbicides tested, the pre-emergence application of imazethapyr (100 g a.i. ha-1) performed better than alachlor (2.0 kg a. i. ha-1), metolachlor at 1.0 kg a.i. ha-1) and pendimethalin (1.0 kg a. i. ha-1). Pre-emergence application of imazethapyr (100 g a. i. ha-1) recorded a higher net returns (Indian 53,220 ha-1) and a higher benefit:cost ratio (2.22) among the herbicide treatments.

Potential Use of Imazethapyr Mixtures in Drill-Seeded Imidazolinone-Resistant Rice

The efficacy of imazethapyr in drill-seeded imidazolinone-resistant rice was evaluated in Louisiana in 2000 and 2001. Imazethapyr was applied preemergence (PRE), or no PRE, followed by a postemergence (POST) application of imazethapyr alone, or in a mixture with bensulfuron, bentazon plus aciflurofen, carfentrazone, halosulfuron, propanil plus molinate, triclopyr, or V-10029. Imazethapyr applied PRE followed by a POST application of imazethapyr controlled barnyardgrass equivalent to or higher than other treatments evaluated. Red rice control at 35 days after postemergence treatment (DAT) was 66 to 81% with imazethapyr applied PRE followed by any POST application, but a reduction in control was observed with a POST application of imazethapyr. Although alligatorweed control increased with POST applications, these treatments suggested only suppression. Hemp sesbania control never exceeded 10% with imazethapyr-only treatments and at 35 DAT, all POST applications, except bensulfuron, increased control above 84%. Rice yield increased with treatments receiving a PRE application of imazethapyr compared with no imazethapyr applied PRE.

Tolerance of Black Beans (Phaseolus vulgaris) to Soil Applications ofS-Metolachlor and Imazethapyr1

This study was conducted to evaluate the tolerance of two black bean cultivars, AC Harblack and Midnight Black Turtle, to preplant incorporated (PPI) and preemergence (PRE) applications of S-metolachlor at 1.6 and 3.2 kg ai/ha, imazethapyr at 0.075 and 0.15 kg ai/ha, and S- metolachlor plus imazethapyr at 1.6 plus 0.075 and 3.2 plus 0.15 kg ai/ha, respectively, at Exeter and Ridgetown, Ontario, Canada, in 2001 and 2002. There were generally no differences between the two cultivars in their responses to the herbicide treatments. PPI and PRE applications of S- metolachlor did not reduce black bean growth or yield. The PPI and PRE applications of imazethapyr alone or in tank mixture with S-metolachlor at the low and high rates did not have a significant effect on plant height, dry weight, seed moisture content, or yield at Ridgetown but caused as much as 14% visual crop injury at Exeter and reduced plant height, dry weight, and yield as much as 25, 40, and 49%, respectively. The higher rate of either herbici...

Tolerance of cranberry beans (Phaseolus vulgaris) to soil applications of s-metolachlor and imazethapyr

There is little information on the tolerance of cranberry beans to preplant incorporated (PPI) and preemergence (PRE) applications of s-metolachlor and imazethapyr, eithe r alone or in tank mix combination, for selective weed control in cranberry beans in Ontario. Tolerance of two cranberry bean cultivars, Hooter and SVM Taylor, to PPI and PRE applications of s-metolachlor, imazethapyr and their tank mix combination at the label rate (1×) and twice the label rate (2× ) were studied at two Ontario locations (Exeter and Ridgetown) in 2001 and 2002. There were no differences between the two cultivars in their responses to the herbicide treatments. PPI and PRE applications of s-metolachlor alone at the 1× and 2× rate had no effect on visual crop injury and no negative effect on plant height, dry weight and yield compared to the control. The PPI and PRE applications of imazethapyr at the 1× rate did not result in significant visual crop injury, and had no negative effect on bean height and dry weight, but at the 2× rate there was significant visual crop injury, a decrease in height with the PPI application and decreased dry weight with PPI and PRE applications. No negative effect o n cranberry bean yield was observed with the application of imazethapyr at either the 1× or 2× rates. The PPI and PRE applications of the tank mix of s-metolachlor plus imazethapyr at the 1× rate did not result in significant visual crop injury or decreases in bean plant height or dry weight. At the 2× rate, there was significant visual crop injury, a decrease in bean plant height with PPI and PRE applications and decreased dry weight with the PPI application. The tank mix of s-metolachlor plus imazethapyr at the 1× rate had no effect on yield, but the PPI application at the 2× rate caused a decrease in yield at 1 of the 4 site-years. Key words:

Grassland Legume Establishment with Imazethapyr and Imazapic

Legumes are important components of grassland communities in North America and have potential to improve grassland productivity and diversity. Weeds can interfere with the establishment of legumes and increase probability of stand failure. Four experiments were conducted from 1994 to 1997 to determine if the imidazolinone herbicides imazethapyr [2‐[4,5‐dihydro‐4‐methyl‐4‐(1‐methylethyl)‐5‐oxo‐1H‐imidazol‐2‐yl]‐5‐ethyl‐3‐pyridinecarboxylic acid] and imazapic [(±)‐2‐[4,5‐dihydro‐4‐methyl‐4‐(1‐methylethyl)‐5‐oxo‐1H‐imidazol‐2‐yl]‐5‐methyl‐3‐pyridinecarboxylic acid] applied preemergence at 70 g a.i. ha−1 could reduce weed interference and improve establishment of seeded grassland legumes. Six native legumes and one introduced legume, crownvetch (Coronilla varia L.), were planted into prepared seedbeds at sites near Mead, NE. Legume response to the herbicides varied among species and sites. Crownvetch, partridgepea [Chamaecrista fasciculata (Michx.) Greene; syn. Cassia chamaecrista L.), and purple prairieclover (Dalea purpurea Vent.) exhibited tolerance to both imazethapyr and imazapic in most experiments and their establishment, as indicated by stem density and/or forage yield collected 14 mo after planting, was improved when treated with the herbicides in weedy environments. Imazapic treatment injured leadplant (Amorpha canescens Pursh), Canada tickclover [Desmodium canadense (L.) DC.], and roundhead lespedeza (Lespedeza capitata Michx.), resulting in lower stem densities and/or forage yields than when imazethapyr was applied. Based on these findings, preemergence application of imazethapyr and imazapic can be used to reduce weed interference and improve the establishment of certain grassland legumes.

Protection of Corn (Zea mays) and Sorghum (Sorghum bicolor) from Imazethapyr Toxicity with Antidotes

Antidotes were evaluated under greenhouse conditions for their ability to prevent injury to corn and sorghum from imazethapyr. Corn was more tolerant to imazethapyr and more effectively protected from imazethapyr toxicity than sorghum. Naphthalic anhydride (NA)3, CGA 92194, or flurazole treatment of corn seed reduced plant injury from preemergence applications of imazethapyr. Corn injury from postemergence applications of imazethapyr was decreased by seed treatment with NA or CGA 92194. Sorghum injury from preemergence applications of imazethapyr was not reduced by seed treatment with the antidotes. NA treatment of sorghum seed was the most effective antidote treatment for decreasing injury from postemergence applications of imazethapyr but the level of sorghum protection was much less than that achieved with corn. Corn seedlings grown from NA-treated and untreated seed absorbed equal amounts of14C into the roots from nutrient solution containing14C-imazethapyr. The NA-treated corn plants translocated less of the absorbed14C to the shoots than the untreated plants. NA treatment of corn seeds increased the rate of imazethapyr conversion to soluble metabolites 2-and 10-fold in the corn seedling roots and shoots, respectively. The increased rate of imazethapyr metabolism in corn following NA seed treatment may be responsible for the protection from imazethapyr toxicity.