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An experiment was conducted to find out the effect of different weed control methods on growth, flowering and flower yield in African marigold (Tagetes erecta L.) cv. Pusa Narangi Gainda at the Department of Floriculture and Landscape Architecture, College of Agriculture, Indira Gandhi Agricultural University, Raipur, Chhattisgarh during the kharif season 2016-17. The experiment consisted of twelve treatments combination of different weed control methods. The results indicated that application of pendimethalin @ 1.0 kg/ha followed by one hand weeding at 30 DAT resulted in the maximum plant height (45.33 cm, 80.63 cm and 101.53 cm at 25,50 and 75 DAT, respectively), number of primary and secondary branches plant-1 (3.27, 6.87 and 10.67 primary branches and 8.60, 20.13 and 36.50 secondary branches at 25, 50 and 75 DAT, respectively), maximum plant spread (68.17 cm ), earliest 50 per cent flowering (47.00 days), significantly biggest flower (6.97 cm), maximum weight of flowers plant-1 (126.73 g.), flowers yield ha-1 (136.85 q). Similar treatment i.e. Pendimethalin 30% EC @ 1.0 kg ha-1 (PE) followed by one Hand Weeding at 30 DAT resulted the highest B:C ratio (3.98) followed by Pendimethalin 30% EC @ 1.0 kg ha-1 (PE) + Fenoxaprop - p-ethyl 9.3% EC @ 0.10 kg ha-1 at 30 DAT (PoE) with B: C Ratio (1:3.60) as compared to other treatments. The minimum values for these parameters were recorded in unweeded treatment.

A hydrolytic transformation study was conducted in water of pH 4.0, 7.0 and 9.2 to evaluate the effect of pH on persistence of a new readymix formulation of fomesafen and quizalofop-ethyl. The water samples were fortified at 0.5 and 1 µg mL−1 levels and analysed at 0 (2 h), 1, 3, 7, 15, 30, 60, 90, 120, 150 days interval. Both the analytical methods were validated following SANTE guideline and found accurate based on average recovery of 80–100%, Relative standard deviation (RSD)

Weeds are the major limiting factor for optimum soybean production in India. The herbicide mixture of fomesafen and quizalofop-ethyl provides effective control of a broad spectrum of weeds, but its fate in the tropical soybean ecosystem is unknown and also the risks involved to the consumer and the environment are still unexplored. Hence, a supervised field trial was conducted following the post-emergence application of fomesafen 12% + quizalofop-ethyl 3% in two consecutive seasons. The dissipation of fomesafen followed biphasic double first order in parallel kinetics, whereas quizalofop-ethyl dissipation followed first order kinetics. A significant difference in the persistence of fomesafen was observed due to seasonal variation of meteorological parameters. However, the variation was significant only in plant, but non-significant in soil, in case of quizalofop-ethyl. The overall shorter persistence of both fomesafen and quizalofop-ethyl was recorded in warmer climatic conditions of Season I than Season II. The results thus indicated that care must be taken during application of this herbicide mixture in cold climatic regions, since both the herbicides may exhibit higher stability. The absence of end-point residues at harvest concluded that the formulation is safe for application in tropical agroclimate. The low chronic dietary toxicity and low soil ecological toxicity indicated that the herbicide mixture will offer no threat against consumer health and soil ecosystem. However, there was a concern about the toxicity against soil algal population which needs to be reconfirmed by further studies.

An analytical method was developed to simultaneously determine pyridate, quizalofop-ethyl, and cyhalofop-butyl in brown rice, soybean, potato, pepper, and mandarin using LC-MS/MS. Purification was optimized using various sorbents: primary–secondary amine, octadecyl (C18) silica gel, graphitized carbon black, zirconium dioxide-modified silica particles, zirconium dioxide-modified silica particles (Z-SEP), and multi-walled carbon nanotubes (MWCNTs). Three versions of QuECHERS methods were then tested using the optimal purification agent. Finally, samples were extracted using acetonitrile and QuEChERS EN salts and purified using the Z-SEP sorbent. A six-point matrix-matched external calibration curve was constructed for the analytes. Good linearity was achieved with a determination coefficient ≥0.999. The limits of detection and quantification were 0.0075 mg/kg and 0.01 mg/kg, respectively. The method was validated after fortifying the target standards to the blank matrices at three concentration levels with five replicates for each concentration. The average recovery was within an acceptable range (70–120%), with a relative standard deviation

Field experiment was conducted to find out the effect of pre-emergence(PE) and early post-emergence (EPoE) herbicides on weed control inirrigated blackgram at College of Agricultural Technology, Kullapuram- Theniduring 2015-2016. In this experiment, weed management practice of preemergenceapplication of Pendimethalin 30 EC 1.0 kg a.i. ha-1 at 3 daysafter sowing (DAS), early post-emergence application of Quizalofop ethyl@50 g a.i. ha-1 at 15 DAS, early post-emergence and Imazethapyr each @50 g a.i. ha-1 at 15 DAS and their combinations of Pendimethalin @ 1.0 kgha-1 at 3 DAS followed by either Quizalofop ethyl or Imazethapyr each @50 g a.i. ha-1 were tested against hand weeding twice at 20 and 40 DAS,weedy check and weed-free check as controls in randomized block designreplicated thrice. Among the different weed management practices, preemergenceapplication of Pendimethalin 1.0 kg a.i. ha-1 (3 DAS) followedby Imazethapyr @ 50g a.i. ha-1 as EPoE (15 DAS) recorded relatively lesserproportion of broad-leaved weeds (30.90 and 49.16%) and higher WeedControl Efficiency (WCE) of 91.27 at 60 DAS. Application of pendimethalin1.0 kg a.i. ha-1 PE (3 DAS) followed by Imazethapyr @ 50g a.i. ha-1 as EPoE(15 DAS) registered significantly taller plants (42.22 cm), higher dry matterproduction(2649 kg ha-1), more number of pods per plant (44.19), seedsper pod(5.57) and higher grain yield (1052 kg ha-1). Thus, pre-emergenceapplication of pendimethalin 1.0 kg a.i. ha-1 (3DAS) followed by Imazethapyr@ 50g a.i. ha-1 as EPoE (15DAS) recommended as effective and economicweed management practices on the basis of better weed control, crop growth,and yield of irrigated blackgram.

The effects of biosolids, ZnO, and ZnO/biosolids on soil microorganism and the environmental fate of coexisting racemic–quizalofop–ethyl (rac-QE) were investigated. Microbial biomass carbon in native soil, soil/biosolids decreased by 62% and 52% in the presence of ZnO (2‰, weight ratio). The soil bacterial community structure differed significantly among native soil, soil/biosolids, soil/ZnO, and soil/biosolids/ZnO based on a principal co-ordinate analysis (PCoA) of OTUs and one-way ANOVA test of bacterial genera. Chemical transformation caused by ZnO only contributed 4% and 3% of the overall transformation of R-quizalofop-ethyl (R-QE) and S-quizalofop-ethyl (S-QE) in soil/ZnO. The inhibition effect of ZnO on the initial transformation rate of R-QE (rR-QE) and S-QE (rR-QE) in soil only observed when enantiomer concentration was larger than 10 mg/kg. Biosolids embedded with ZnO (biosolids/ZnO) caused a 17%–42% and 22%–38% decrease of rR-QE and rS-QE, although rR-QE and rS-QE increased by 0%–17% and 22%–58% by the addition of biosolids. The results also demonstrated that the effects of biosolids on agricultural soil microorganism and enantioselective transformation of chiral pesticide was altered by the embedded nanoparticles.

The enantioselective catabolism of the two enantiomers of the aryloxyphenoxypropionate (AOPP) herbicide, quizalofop-ethyl (QE), in environment by microorganisms is of great interest. In this study, Sphingobium sp. strain QE-1, capable of transforming both enantiomers of QE, was successfully isolated. A novel gene qeH, encoding an esterase capable of initially transforming (R)/(S)-QE to (R)/(S)-quizalofop acid [(R)/(S)-QA], was cloned. QeH showed the highest identity (36.9%) to the β-lactamase MT1414, and the purified QeH displayed optimal activity for (R)-QE at 40 °C and pH 7.0. QeH preferentially hydrolyzed (R)-QE than (S)-QE. Based on molecular docking analyses, the distance between the ligand molecule and the coordination atom was shorter when (R)-QE occupied the active sites as compared to that of (S)-QE, which resulted in a stronger ligand binding affinity for (R)-QE. Besides the two enantiomers of QE, QeH could also convert many other AOPP herbicides with different catalytic efficiency (clodinafop-propargyl > fenoxaprop-P-ethyl > fluazifop-P-butyl > cyhalofop-butyl). This study will enhance our understandings of the enantioselective catabolism of AOPP herbicides by microorganisms.

The experiment was conducted during Kharif season of 2006 at Junagadh (Gujarat) to study the weed dynamics and yield as influenced by various weed control practices with different fertility levels in soybean [ Glycine max (L.) Merril]. Results indicates that at 20 DAS the treatment W 1 (Pre-emergence pendimethalin @ 0.5 kg ha -1 + HW and IC at 30 DAS) recorded lowest number of monocots, dicots and sedges weeds next to W 5 (Weed free upto 60 DAS through hand weeding). Similarly at 40 and 60 DAS the treatment W 3 (Post-emergence imazethapyr @ 75 g ha -1 at 25 DAS + HW and IC at 45 DAS) also reported minimum number of weeds next to W 5 . The lowest dry weight of weeds was recorded under treatment W 5 followed by W 4 and W 3 . Application of 40:80:40 kg NPK ha -1 recorded significantly higher values of weed count and total dry weight of weeds and grain yield compared to other levels. The treatment W 4 (2 HW + 2 IC at 20 and 40 DAS) was found at par with treatment W 5 in respect of grain yield.

The effects of herbicides, alone application or in combination with insecticides, on performance of soybean [Glycine max (L.) Merrill] were examined at ICAR- Indian Agricultural Research Institute, New Delhi during rainy seasons of 2013 and 2014. Alone application of imazethapyr 10 SL @ 1.0 l/ha or in combination with indoxacarb 14.5 SC @ 300 ml/ha and rynaxypyr 20 SC @ 100 ml/ha lowered monocot and dicot weed count, reduced weed dry matter and increased weed control efficiency in comparison with other herbicide and insecticide applications, individual or in combinations. These results suggested that the imazethapyr can effectively control different categories of weeds, especially of monocots in soybean field. However, seed yield, net returns and B: C ratios were higher in the quizalofop ethyl 5 EC (1.0 l/ha) applied plots followed by combined application of rynaxypyr 20 SC (100 ml/ha) + quizalofop ethyl 5 EC (1.0 l/ha)).

A field experiment was conducted during rainy seasons of 2011 and 2012 at Udaipur to evaluate the effect of weed control and sulphur on yield and quality of soybean [Glycine max (L.) Merrill]. The twenty eight treatment combinations comprising 7 weed management treatments (weedy check, pendimethalin 1.0 kg ha-1 pre- emergence, quizalofop-ethyl 50 g ha-1 and imazethapyr 100 g ha-1 post-emergence at 15 DAS, pendimethalin, quizalofop-ethyl and imazethapyr followed by hoeing and weeding at 30 DAS) in main plot and 4 rates of sulphur application (00, 20, 40 and 60 kg ha1) in sub plot were laid out in split plot design with three replications. All weed control treatments reduced weed dry matter at harvest during both the years. Pendimethalin followed by hoeing and weeding at 30 DAS was significantly superior in reducing weed dry matter of broad-leaved, narrow-leaved and total weeds at harvest over rest of the treatments. All weed control treatments significantly enhanced straw and biological yield of soybean over weedy check. Pendimethalin followed by hoeing and weeding at 30 DAS produced significantly higher pooled seed (2168 kg ha-1), straw (3167 kg ha-1) and biological (5335 kg ha-1) yields compared to other treatments. Sulphur rates had no significant effect on weed dry matter at harvest. Across the years, increasing level of S application up to 40 kg ha-1 resulted in significantly increased straw yield, biological yield and harvest index of soybean. Increasing rate of sulphur application up to 40 kg ha-1 tended to significantly increase protein and oil yield.

Mechanisms of herbicide resistance were studied in a quizalofop–ethyl-resistant barnyardgrass biotype. Acetyl-coenzyme A carboxylase (ACCase) sensitivity to quizalofop-p-ethyl was measured by high-performance liquid chromatography and the trend in ACCase gene expression over time was determined using real-time polymerase chain reaction. The results showed that an insensitive ACCase was present in Geqiushan resistant plants (R), with a resistance index of 106. The basal ACCase activities in Geqiushan R and Geqiushan susceptible plants (S) were similar, at 1.20 and 1.17 ng malonyl-CoA min−1µg−1extract protein, respectively. Basal ACCase gene expression in Geqiushan R was similar to that in Geqiushan S. The relative expression of ACCase gene decreased after spraying quizalofop–ethyl at 60 g ai ha−1in Geqiushan S, whereas it was almost not changed in Geqiushan R. From these results we concluded that plastid ACCase sensitivity change might be responsible for the resistance and gene overexpression does not play a role in this resistance.

The lethal and sublethal effects of three post-emergence herbicides, 2,4-D ethyl ester (Weedkill 80WP), imazethapyr (Pursuit 10EC) and quizalofop ethyl (Tergasuper 5EC) fortified with artificial diets were studied on larvae of Spilarctia obliqua Walker (Lepidoptera: Arctiidae). Quizalofop ethyl and imazethapyr caused significant reduction of pest survival at almost all levels; however, 2,4-D ethyl ester was nontoxic. Interestingly, LC50 data (0.230 and 0.855% for quizalofop ethyl and imazethapyr, respectively) obtained from probit analysis were almost equal to labeled doses (x) of quizalofop ethyl (x = 0.16%) and imazethapyr (x = 0.625%), which shows the high toxicity of these compounds against S. obliqua larvae. Among the three herbicides, imazethapyr caused sublethal effects on this pest, increasing the larval period at almost all concentrations tested in the artificial diet. Considering the markedly significant effect of quizalofop ethyl on pest survivorship with no sublethal effect, we suggest incorporating it into the integrated pest management module for S. obliqua in legumes or oilseed crops with other biorational insecticides. Based on toxicity, imazethapyr can be a potential candidate for integrated management of S. obliqua. However, because of its sublethal effects, we advocate caution while using it in the presence of pest infestations.

Quizalofop ethyl, a phenoxy propionate herbicide is used for post emergence control of annual and perennial grass weeds in broad-leaved crops in India. The experiments were designed to study the harvest time residues of quizalofop ethyl in black gram for two seasons. At harvest time, the residues of quizalofop ethyl on black gram seed, foliage and soil were found to be below the determination limit of 0.01 mg kg(-1) following a single application of the herbicide at 50 and 100 g a.i. ha(-1) for both the periods. Application of the herbicide is quite safe from a consumer and environmental point of view.

Several derivatives of heterocyclic-oxy phenoxy propionic acid have been known as selective herbicides. During extensive investigations on this series with various condensed heterocyclic moieties, the quinoxalinyloxy phenoxy propionic acid derivatives were found to show an excellent herbicidal activity against grass weeds. Among them, ethyl 2- [4- (6-chloro-2-quinoxalinyloxy) phenoxy] propionate, (code No.NC-302, quizalofop ethyl) showed a potent herbicidal activity. It is commercialized as a novel post-emergence herbicide. In this paper, facile syntheses of substituted quinoxalines and quizalofop ethyl derivatives are described in detail.

選択性除草剤として,フェノキシプロピオン酸エステルあるいはピリジルオキシプロピオン酸エステルが知られている。著者らはフェノキシあるいはピリジルオキシに代わって縮合ヘテロ環を幅広く検討する中,キノキザリン類の中に細葉雑草の除草に卓効のある,有望な化合物群を見いだした。その中で,キザロホップェチル(コード No. NC-302 )は特に強い効力を持ち,茎葉処理型除草剤として企業化された。その工業化に際し,キノキザリン環部の合成は大きな課題の一つであったが,汎用な原料から合成できる簡単な方法を見いだした。また,キザロホヅプェチルは不斉炭素を持ち,光学異性体が存在するが,その有効成分は(R)-(+)体であり,ラセミ体にくらべて2倍の効果を持つ。(0)0(+)体の製造は,分割法ではなく,光学活性な原料を使いラセミ化させない方法で行っている。また,(R)-(+)体は,ラセミ体とは異なり結晶型が二つ存在する。この分測晶析法が発見され,(R)一(+)体の工業化が可能となった。本論文では,特に光学活性キザロホップエチルと,その重要な中間体である2-(4ヒドロキシフェノキシ)プロピオン酸エチルの製造法について,詳しく述べる。

Several derivatives of heterocyclic-oxy phenoxy propionic acid have been known as selective herbicides. During extensive investigations on this series with various condensed heterocyclic moieties, the quinoxalinyloxy phenoxy propionic acid derivatives were found to show an excellent herbicidal activity against grass weeds. Among them, ethyl 2- [4- (6-chloro-2-quinoxalinyloxy) phenoxy] propionate, (code No.NC-302, quizalofop ethyl) showed a potent herbicidal activity. It is commercialized as a novel post-emergence herbicide. In this paper, facile syntheses of substituted quinoxalines and quizalofop ethyl derivatives are described in detail.