Propesticides and Their Implications

With increasing knowledge of the biochemistry and genetics of major pest insects, weeds, and agricultural pathogens, the design of such selectivity becomes a part of pesticide development and is achieved by appropriate structural modification of the parent lead molecule which is called as propesticide. In a strict sense, a propesticide is a biologically inactive compound requiring structural transformation(s) after application to become pesticidally active. Various pesticides have come to the limelight of being a propesticide by carrying out studies on their metabolic fate in organisms. Studies on the metabolic fate of diafenthiuron in vitro by liver microsomes from various vertebrates revealed a variety of possible transformations of the thiourea. Few have been developed by reversibly masking the active ingredients. Fluorinated N-acylaziridine behaves as a propesticide of the fluorinated carboxylate and the hydrolysis of the former to 2-methylaziridine and carboxylate being activation pathway. Imidacloprid and the thiazolylmethyl analogue masked with oxodioxolyl group decomposed with half life of 15.4 and 11.4 h in alkaline and physiological salt solutions, respectively, releasing imidacloprid quantitatively. New propesticide with two effects of both benzoylphenyl ureas and carbamates were designed and synthesized

Electrochemical micro analytical device interfaced with portable potentiostat for rapid detection of chlorpyrifos using acetylcholinesterase conjugated metal organic framework using Internet of things

An Electrochemical micro Analytical Device (EµAD) was fabricated for sensitive detection of organophosphate pesticide chlorpyrifos in the food chain. Gold microelectrode (µE) modified with Zinc based Metal Organic Framework (MOF-Basolite Z1200) and Acetylcholinesterase (AChE) enzyme served as an excellent electro-analytical transducer for the detection of chlorpyrifos. Electrochemical techniques such as Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Differential Pulse Voltammetry (DPV) were performed for electrochemical analysis of the developed EµAD. The sensor needs only 2 µL of the analyte and it was tested within the linear range of 10 to 100 ng/L. The developed EµAD’s limit of detection (LoD) and sensitivity is 6 ng/L and 0.598 µ A/ng L−1/mm2 respectively. The applicability of the device for the detection of chlorpyrifos from the real vegetable sample was also tested within the range specified. The fabricated sensor showed good stability with a shelf-life of 20 days. The EµAD’s response time is of 50 s, including an incubation time of 20 s. The developed EµAD was also integrated with commercially available low-cost, handheld potentiostat (k-Stat) using Bluetooth and the results were comparable with a standard electrochemical workstation

Inclusion Distribution in Ingots - A Guide to Segragation Mechanism

The melting point of non-metallic inclusion, and their nature and distribution can be a guide in deciphering the mode of solidification and segregation in an ingot. A commercial ingot was sectioned, and examined micros-copically. Inclusion identification was carried out by optical method as well as by electron probe micro analy-sis. The exten of segregation was obtained by extensive spectro-chemical analysis. It has been found that the shape and position of bottom cone of negative segregation coincide with that of bottom cone of inclusions. A theory of ingot segregation has been suggested that the bottom cone of oxide inclusions is a result of incorporation of these inclusions inthe dendrites of equiaxed grains. The inclusions drop to the bottom end with the shower of relatively pure equiaxed grains. While the interdendritic fluid is enriched in elements like C, Mn, S, P, it is denuded of oxygen. Since the oxygen solubility is low, oxygen enrichment leads to immediate precipitation of oxides

Persistence of Azoxystrobin in/on Grapes and Soil in Different Grapes Growing Areas of India

Persistence of azoxystrobin was studied in/on grapes when applied @ 150 g ai ha−1 (recommended dose) and 300 g ai ha−1 (double the recommended dose) in three grapes growing states of India, namely Karnataka, Maharashtra and Tamil Nadu, in the year 2006–2007. A total of five sprays were given at an interval of about 15 days. Grapes and soil samples were collected after 5th spray, extracted and analysed by gas chromatography using electron capture detector. Half life of azoxystrobin on grapes varied from 5.4 to 11.2 days. Residues of azoxystrobin were much below the prescribed MRL (0.5 mg kg−1) after 21 days. The dissipation of azoxystrobin in soil followed first order rate kinetics with an average half life of 8.1 days at the recommended dose of application

Risk Assessment of a Synthetic Pyrethroid, Bifenthrin on Pulses

This work was undertaken to determine the pre-harvest interval of bifenthrin and to minimize its residues in pulses and thereby ensure consumer safety and avoid non-compliance in terms of residues violations in export market. Furthermore the residue dynamics in the soil under pulses was explored to assess the environmental safety. The residues of bifenthrin dissipated following first order kinetics. The residues in harvest time grains were below the maximum residue limit (MRL) of 0.02 mg/kg applicable for European Union. In soil the degradation rate was fast with a half life of 2–3 days. This work is of high practical significance to the domestic and export pulse industry of India to ensure safety compliance in respect of bifenthrin residues, keeping in view the requirements of international trade

Electrochemical micro analytical device interfaced with portable potentiostat for rapid detection of chlorpyrifos using acetylcholinesterase conjugated metal organic framework using Internet of things

An Electrochemical micro Analytical Device (EµAD) was fabricated for sensitive detection of organophosphate pesticide chlorpyrifos in the food chain. Gold microelectrode (µE) modified with Zinc based Metal Organic Framework (MOF-Basolite Z1200) and Acetylcholinesterase (AChE) enzyme served as an excellent electro-analytical transducer for the detection of chlorpyrifos. Electrochemical techniques such as Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Differential Pulse Voltammetry (DPV) were performed for electrochemical analysis of the developed EµAD. The sensor needs only 2 µL of the analyte and it was tested within the linear range of 10 to 100 ng/L. The developed EµAD’s limit of detection (LoD) and sensitivity is 6 ng/L and 0.598 µ A/ng L−1/mm2 respectively. The applicability of the device for the detection of chlorpyrifos from the real vegetable sample was also tested within the range specified. The fabricated sensor showed good stability with a shelf-life of 20 days. The EµAD’s response time is of 50 s, including an incubation time of 20 s. The developed EµAD was also integrated with commercially available low-cost, handheld potentiostat (k-Stat) using Bluetooth and the results were comparable with a standard electrochemical workstation

Fate of tribenuron-methyl in soil and water

52-54Persistence of tribenuron in different soil types (namely alluvial, black and red soil) having different pH values maintained at field capacity moisture regime and in water at three different pH levels i.e. 4, 7 and 9.2, respectively was studied under laboratory conditions at two levels of application, 1.0 and 2.0 mg–1. Samples were processed periodically and analyzed by HPLC. Tribenuron dissipated to 91.04-90. 41% in alluvial and black soil, whereas in red soil with pH 6.64, it dissipated to 94.7% by day 5 after fortification. The half-life values calculated from the first order dissipation kinetics varied from 1.67 in red soil with pH 6.1 to 3.47 in alluvial soil with pH 8.1, indicating that tribenuron is more persistent in soil with basic pH and degrades faster in acidic soil. Slowest dissipation was recorded at neutral and basic pH

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Not AvailablePesticide persistence and degradation in soil are influenced by factors like soil characteristics, light, moisture etc. Persistence of tricyclazole was studied under different soil moisture regimes viz., dry, field capacity and submerged in two different soil types viz., Inceptisol and Ultisol from Delhi and Karnataka, respectively. Tricyclazole dissipated faster in submerged (t1 /2 160.22-177.05 d) followed by field capacity (t1/2 167.17-188.07 d) and dry (tl /2 300.91-334.35 d) in both the soil types. Half-life of tricyclazole in Delhi field capacity soil amended with Blue Green Algae (BGA), was 150.5 d as compared to 167.1 d in unamended soil. In Karnataka soil amended with BGA the half-lives were 177.0 d compared to 188.0 d in unamended soil, indicating that BGA amendment enhanced the rate of dissipation of in both the selected soils. Tricyclazole was found to be stable in water over a pH range of 3-9, the half life in paddy field was 60.20 d and 5.47 din paddy soil and paddy water, respectively. Statistical analysis and Duncan's Multiple Range Test (DMRT) revealed significant effect of moisture regime, organic matter and atmospheric CO2 level on dissipation of tricyclazole from soil and pH of water (at 95% confidence level p <0.0001). (C) 2016 Elsevier B.V. All rights reserved.IARI fellowshi

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Not AvailableClothianidin is a widely used insecticide under Indian subtropical condition. The objective of this study was to generate residue data which aims to understand leaching potential of clothianidin [(E) - 1 - (2 - chloro - 1,3 - thiazol - 5 - ylmethyl) - 3 - methyl - 2 - nitroguanidine] through packed soil column. The maximum amount of clothianidin was recovered at 0-5 cm soil depth in both Manipur (67.15%) and Delhi soil (52.0%) under continuous flow condition. Manipur and Delhi soil concentrated maximum residue with or without farm yard manure (FYM) in 0-20 cm soil depth. The effect of varying the amount of water enhanced the distribution of residues in the first 0-5 cm layer. Among the tested soils, residue was detected in the leachate from Delhi soil (0.04 A mu g/mL). Clothianidin leaching was minimized in soil of Manipur compared to Delhi after incorporation of FYM. As the volume of water increased upto 160 mL, mobility increased and residues moved to lower depth. Clothianidin did not leach out of the 25 cm long soil columns even after percolating water equivalent to 415.42 mm rainfall. Clothianidin is mobile in soil system and mobility can be reduced by organic amendment application.IARIIndian Council of Agricultural Research (ICAR