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Multi–locational supervised field trials were conducted in different agro–climatic regions in India to study dissipation of trifloxystrobin and tebuconazole in tomato after spraying a combination formulation (trifloxystrobin 25% + tebuconazole 50%, 75WG) at recommended doses: (i) single (trifloxystrobin 87.5 g a.i. ha−1 + tebuconazole 175 g a.i. ha−1) and (ii) double (trifloxystrobin 175 g a.i. ha−1 + tebuconazole 350 g a.i. ha−1). Fruit samples were extracted with ethyl acetate using a modified QuEChERS method. The residues (parent fungicides + metabolite) were analyzed and confirmed by GC–ECD and GC–MS, respectively. The half–life (t1/2) of trifloxystrobin and tebuconazole in tomato varied from 1.08 to 1.72 and 1.13 –to 1.64 days at single; and 1.27 to 2.13 and 1.24 to 1.96 days at double dose, respectively. Since maximum residue limit (MRL) at pre–harvest interval (PHI) of 5 days is impractical, as tomato is usually harvested and consumed almost everyday after the last spray, the risk assessment was performed at minimum PHI of 1 day. Accordingly, on the basis of supervised field trial data and using OECD MRL calculator, MRL of 0.5 and 1.5 mg kg−1 at single dose were proposed for trifloxystrobin and tebuconazole in/on tomato, respectively.

The study was aimed to develop a nano form of an existing fungicide for improving plant protection and reducing crop losses caused by fungal pathogens. The protocol for the preparation and estimation of nanohexaconazole was developed. Technically pure hexaconazole was converted into its nanoform using polyethyleneglycol-400 (PEG) as the surface stabilizing agent. Nanohexaconazole was characterized using Scanning Electron Microscopy (SEM) and Dynamic Light Scattering (DLS) studies. The average particle size of nanohexaconazole was about 100 nm. An analytical method was also developed for quality control of the nanofungicide by GLC fitted with flame ionization detector. Its limit of detection was 2.5 ppm. Fungicidal potential of nanohexaconazole was better in comparison to that of conventional hexaconazole. Hydrolytic and thermal stability studies confirmed its stability at par with the conventional formulation of fungicide. Impact of nanohexaconazole on soil nitrifiers was tested in vitro and there were no significant adverse effect in their numbers observed as compared to conventional registered formulation, proving the safety of the nanofungicide.

Multi-location supervised field trials were conducted in India at four locations of the All India Network Project (AINP) on Pesticide Residues to study the persistence, dissipation and risk assessment of flubendiamide and deltamethrin on cucumber (Cucumis sativus). Residues of flubendiamide and deltamethrin on cucumber resulting from three spray applications of a combination formulation (flubendiamide 90% + deltamethrin 60%, 150 SC) at recommended (22.5 + 15 g a.i./ha) and double the recommended (45 + 30 g a.i./ha) dose were analysed. On the basis of persistence and dissipation studies, the half- life (T1/2) of flubendiamide on cucumber varied from 1.40 to 2.98 (recommended dose) and 1.55 to 2.76 days (double the recommended dose), while that of deltamethrin ranged from 2.5 to 4.9 (recommended dose) and 2.7 to 3.9 days (double the recommended dose) at the four locations. On the basis of supervised field trial data and using OECD calculator, MRLs in the combination product of 3 mg kg-1 for flubendiamide and 1.5 mg kg-1 for deltamethrin has been proposed for consideration by the Food Safety and Standards Authority of India (FSSAI). Codex, EU and EPA have fixed MRL of 0.2 mg kg-1 for flubendiamide and deltamethrin.

Bacteria capable of degrading the sulfonated azo dye Red HE7B were isolated from textile mill effluent contaminated soil. The most efficient isolate was identified as Bacillus sp. Azo1 and the isolate could successfully decolorize up to 89 % of the dye. The decolorized cultural extract analyzed by HPLC confirmed degradation. Enzymatic analysis showed twofold and fourfold increase in the activity of azoreductase and laccase enzymes, respectively, indicating involvement of both reductive and oxidative enzymes in biodegradation of Red HE7B. Degraded products which were identified by GC/MS analysis included various metabolites like 8-nitroso 1-naphthol, 2-diazonium naphthalene. Mono azo dye intermediate was initially generated from the parent molecule. This mono azo dye was further degraded by the organism, into additional products, depending on the site of cleavage of R–N=N–R molecule. Based on the degradation products identified, three different pathways have been proposed. The mechanism of degradation in two of these pathways is different from that of the previously reported pathway for azo dye degradation. This is the first report of a microbial isolate following multiple pathways for azo dye degradation. Azo dye Red HE7B was observed to be phytotoxic, leading to decrease in root development, shoot length and seedling fresh weight. However, after biotreatment the resulting degradation products were non-phytotoxic.

Nanohexaconazole is a highly efficient fungicide against Rhizoctonia solani. Nanoparticles are alleged to adversely affect the non-target organisms. In order to evaluate such concern, the present study was carried out to investigate the effect of nanohexaconazole and its commercial formulation on sensitive nitrogen fixing blue green algae (BGA) and bacteria. Various activities of algae and bacteria namely growth, N-fixation, N-assimilation, Indole acetic acid (IAA) production and phosphate solubilization were differently affected in the presence of hexaconazole. Although, there was stimulatory to slightly inhibitory effect on the growth measurable parameters of the organisms studied at the recommended dose of nanohexaconazole, but its higher dose was inhibitory to all these microorganisms. On the other hand, the recommended as well as higher dose of commercial hexaconazole showed much severe inhibition of growth and metabolic activity of these organisms as compared to the nano preparation. The uses of nanohexazconazole instead of hexaconazole as a fungicide will not only help to control various fungal pathogens but also sustain the growth and activity of these beneficial microorganisms for sustaining soil fertility and productivity.

Eggplant shoot and fruit borer (ESFB), Leucinodes orbonalis G. is a key pest of eggplant, Solanum melongena L. Organophosphates (OP) having high toxicity and persistence are used to control the pests in many developing countries, despite availability of new insecticides with better qualities. Field evaluation of thiacloprid and indoxacarb were carried out against ESFB, with an OP insecticide, methyl parathion. Two Bacillus thuriegensis (Bt) based formulations namely Biolep and PUSA Bt and two azadirachtin formulations namely Neem Seed Kernal Extract (NSKE) and Nimbo Bas were also evaluated against ESFB for the management of the pest. HPLC and GC methods for the estimation of indoxacarb, thiacloprid and methyl parathion from the fruits were developed and their dissipation patterns and safety parameters were compared. For indoxacarb, the method involving Florisil gave highest recovery (88%) whereas average recoveries of other methods varied from 59% to 82%. The mean initial deposits of indoxacarb on fruits were 2.60 mg/kg to 3.64 mg/kg and 2.63 mg/kg to 3.68 mg/kg from 75 and 150 g·ai/ha treatments from two-year field studies. The half-life of indoxacarb was 3.0 d - 3.8 d from both years. The Theoretical Maximum Daily Intake (TMDI) was found to be 0.446 mg/person/day to 0.643 mg/person/day for day-1 residues which is in par with the Maximum Permissible Intake (MPI) of 0.6 mg/person/day. The TMDI from 3 d residues was found to be less than the MPI calculated with the data of 3 d residues which ensures better margin of safety. For thiacloprid, the method involving Florisil gave highest recovery (89%). The mean initial deposits of thiacloprid on fruits were 3.39 to 5.40 mg/kg and 3.40 to 5.39 mg/kg from 30 and 60 g·ai/ha treatments from both years. The half-life values were determined to be 11.1 and 11.6 d for both years. The TMDI from maximum residues observed for first day for both the treatments during first year trials was found to be 0.682 to 1.098 mg person/day, which was higher than the MPI of 0.72 mg/person/day, which proved that the application is toxic to humans. Thiacloprid at the experimented doses (30 and 60 g·ai/ha) was found not effective to manage ESFB and was not safe for human consumption after a waiting period of 3 days. For methyl parathion, the method involving Florisil gave highest average recovery (89%). The initial residues on fruits from recommended dose declined from 3.60 to 3.12 mg/kg in one day and 0.27 mg/kg in twentyfive days from 100 g·ai/ha. Similar pattern was observed with higher dose also. The dissipation rate constants were 0.123 and 0.140 for 100 and 200 g·ai/ha treatments, respectively. The half life values ranged from 6.0 to 7.4 days. Using dose (100 g·ai/ha), the residues reached safe level only after 20 days. A minimum gap of 20 days after the last application of the insecticide to the harvest is impractical for this crop. The efficacy of methyl parathion against ESFB was good at lower dose, but due to its toxic residue profile there is a high health risk. Biolep at both doses were not effective against ESFB, however PUSA Bt gave better control against ESFB at similar dose. NSKE was found effective against ESFB, however NimboBas found to be non-effective against ESFB.

A series of twenty substituted 3,4-dihydropyrimidine derivatives were prepared and characterized by TLC, IR, 1H NMR, 13C NMR spectroscopic data and elemental analysis. These were screened for insecticidal activity by the film residue method against the pulse beetle (adzuki bean weevil, Callosobruchus chinensis). 4-(2′-Chlorophenyl)-6-phenyl-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00201 mg/cm2), 4-(2′-chlorophenyl)-6-p-tolyl-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00122 mg/cm2), 4-(4′-methoxyphenyl)-6-(4″-methylphenyl)l-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00164 mg/cm2), 4-(4′-chlorophenyl)-6-(4″-methoxyphenyl)-3,4-dihydropyrimidine-2(1H)-thione (LC50 0.00175 mg/cm2) were found to be more effective than dichlorvos (2,2-dichlorovinyl dimethyl phosphate, LC50 0.00243 mg/cm2), a commercial insecticide recommended for managing Callosobruchus chinensis.

An alkalotolerant Pseudomonas strain was enriched and isolated from effluent of the pulp and paper industry. This strain was able to degrade dibenzofuran and utilize it as a sole source of energy and carbon. The GC-MS based detection of various intermediary metabolites of biodegradation suggested the involvement of angular as well as lateral pathway of dibenzofuran biodegradation. The GC-MS based detection of various intermediary metabolites of biodegradation suggested the involvement of angular as well as lateral pathway of dibenzofuran biodegradation. This diverse dioxygenation property of the strain allowed it to utilize various recalcitrant chlorinated xenobiotics and PAHs compounds. This strain showed optimum utilization (~85%) of dibenzofuran (200 mg l⁻¹) within 36 h at pH 10 at 40 °C. The growth of the strain was supported by a wide range of environmental conditions such as temperature, pH, and concentration of dibenzofuran, suggesting that it can be used for in situ bioremediation of dioxin-like compound.

A series of twenty 3,5-disubstituted isoxazoles were synthesized (using conventional and microwave methods) by the reaction of substituted chalcones with hydroxylamine hydrochloride and characterized by TLC, IR, 1H NMR, 13C NMR spectroscopic data and elemental analysis. The compounds were screened for insecticidal activity against the pulse beetle, Callosobruchus chinensis. Compounds 1a (LC50 36 mg L−1), 1d (LC50 110 mg L−1), 2c (LC50 93 mg L−1) and 5b (LC50134 mg L−1) were more effective than the recommended organophosphorous insecticide dichlorvos (2,2-dichlorovinyl dimethyl phosphate) (LC50 155 mg L−1). These compounds provide a lead for designing new substances endowed with insecticidal activity.

Studies were undertaken to analyze the residues of commonly used pesticides viz. chlorpyrifos, endosulfan, dicofol, cypermethrin, fenvalerate, propargite, malathion, phorate, carbendazim, carbosulfan, thiamethoxam, and mancozeb in apple of integrated pest management (IPM) and non-IPM samples collected from the IPM and non-IPM fields of Shimla. We also present a method for the determination of these pesticides in apple samples. Residues of chlorpyrifos, endosulfan, dicofol, cypermethrin, fenvalerate, and propargite were analyzed by gas chromatography, while residues of carbendazim, carbosulfan, and thiamethoxam were analyzed by high-performance liquid chromatography. Residues of mancozeb were determined by a colorimetric method. Recoveries of all of the pesticides ranged from 61.30 to 95.46% at 0.1, 0.2, and 1.0 microg g(-1) levels of fortification with relative standard deviations ranging between 0.8 and 8.7. Apples from IPM and non-IPM orchards were analyzed for these pesticides using a developed method. Except for carbendazim and chlorpyrifos, the residues of all of the pesticides analyzed were below detectable limits. Although residues of carbendazim and chlorpyrifos were below the prescribed limits of maximum residue levels in both IPM and non-IPM orchards, residues were lower in apples from IPM orchards.

BACKGROUND: Thiacloprid [(Z)-3-(6-chloro-3-pyridylmethyl)-1,3-thiazolidin-2-ylidenecyanamide; Calypso™] is a systemic insecticide having persistence in the plant system. It was chosen for the management of the eggplant shoot and fruit borer, Leucinodes orbonalis Guen. Management of this insect pest is difficult because it harbours inside the shoot and fruit portions of eggplant. The persistence of thiacloprid on eggplant has not been studied in India. The Food and Agriculture Organisation (FAO) has proposed its maximum residue limit (MRL) on eggplant as 0.7 mg kg−1, and there is a need to validate this value. Since residues were found to be above this level, five different decontamination agents were tested for the decontamination of thiacloprid from eggplant. RESULTS: The half-life of thiacloprid was 11.1 and 11.6 days from trials in 2 years. Safety factors such as theoretical maximum daily intake (TMDI) and maximum permissible intake (MPI) were used to arrive at a risk assessment to human health from the analytical data obtained from the field trials. Thiacloprid at the doses tested (30 and 60 g AI ha−1) was not effective in managing eggplant fruit borer. A waiting period of 3 days before harvest of the fruits after insecticide application and a processing factor (PF) could not ensure a sufficient margin of safety (MOS). Subjecting the data to a processing factor of 60% could not bring the residues below the proposed MRL. CONCLUSION: Thiacloprid is not found to be an appropriate and effective agent for application to eggplant. Either the proposed MRL needs to be revised or good agricultural practice involving thiacloprid for plant protection in eggplant cultivation is required. Copyright © 2008 Society of Chemical Industry

Mango (Mangiferae indica L.) is an important exporthorticultural crop of India. Various insects and diseasesinfest the fruit especially in the fruiting season. The com-mon insect pests are mango leafhopper, mealy bug, leafwebber, inflorescence midge and fruit fly. The major lossof about 60% is due to leafhopper and mango leafhopper.These pests infest the mango at the floral and bud stage tofruit setting, tender leaves and small fruits. The crop pro-tection measures undertaken to control pest infestation in-volves spray of insecticides along with biological andcultural practices.India produces 65% of the world’s mango crop,9,000,000 MT, but with very little export. Although, Asiaaccounts for 75% world production, its dominance does nottranslate into international trade. The presence of pesticideremnants in mango lowers the export quality of mangofruits in the international market. To increase foreign trade,under the WTO regime, it is imperative to produce pesti-cide free mangoes.The insecticides commonly applied by the farmers areendosulfan, parathion methyl, chlorpyrifos, cypermethrinand fenvalerate. This paper presents a method for theestimation of the multi-class pesticides in mango and theirrecovery.Materials and MethodSolvents like acetone, dichloromethane, hexane (analyticalgrade), were distilled before use. Adsorbents neutral alu-mina and Florisil were activated before use. Pesticidestandards of methyl parathion, endosulfan, chlorpyrifos,cypermethrin and fenvalerate were of analytical gradequality. Gas Chromatogram instrumen-Shimadzu GC-17Afitted with an auto-sampler and ECD detector was used foranalysis. Other minor equipments required were rotaryevaporator and Waring blender, etc.Individual stock standard solutions (1,000 lg/mL) ofparathion methyl, endosulfan, chlorpyrifos, cypermethrinand fenvalerate were prepared in hexane (analytical grade).Working standard solutions of each pesticide was preparedby serial dilutions to 100 lg/mL, which was further dilutedto 0.1–10 lg/mL as per detector response. All the stocksolutions were stored at 4 C. Appropriate aliquot of indi-vidual pesticides solutions were taken and a mixture of fivepesticides of 100 lgmL

Lactofen, a member of the diphenyl ether chemical family, shows great potential for the control of broadleaf weeds associated with leguminous crops. It presents a high degree of selectivity when applied post-emergence to soybean and peanut crops. This paper presents the persistence of lactofen under a soybean crop under various conditions, including without remediation techniques, under soil solarization with polyethene sheets, and soil solarization followed by straw amendment. The results indicate that dissipation is faster when using the soil solarization technique (set II) compared to no treatment (set I) and is further enhanced by tstraw amendment, where almost 90% dissipation was recorded (set III). The dissipation followed first-order kinetics with a half-life that varied from 30 to 10 days. The half-life of lactofen was 15 days in treatments of soil solarization and straw amendments alone, indicating that both techniques have to be used in combination to achieve successful remediation of soil. Use of biodegradable polythene/substitute material will make this process a popular technique and may also improve its commercial viability.

Smart formulations based on nanomaterials have the capability to reduce the consumption of hazardous pesticides and their impact on human health and environment. Nanoformulations of agrochemicals have the potential to improve food productivity without compromising with the ecosystem. In the present work, controlled release nanocapsules containing acetamiprid were prepared by polyelectrolyte complexation of two natural macromolecules, i.e. alginate and chitosan. The size, morphology and chemical interaction studies of the prepared nanocapsules were investigated by Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The zetapotential studies revealed stability of the nanocapsules. TEM results show spherical morphology of the nanocapsules. The encapsulation efficiency was found to be 62% as quantified by Ultra High Pressure Liquid Chromatography (UHPLC). Nanocapsules were analysed for controlled release in vitro at three different pH. Maximum release was observed at pH 10 followed by pH 7 and 4, respectively. A non-Fickian release mechanism was found to be followed by the nanoformulation. A controlled release pattern was also found from nanoformulation as compared to commercial formulation in soil. Thus this formulation can reduce the frequency of application of pesticides by controlling the release and will subsequently reduce their side effects.

β-Cyfluthrin [α-cyano-4-fluoro-3-phenoxybenzyl-3(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate] pesticide has been in agricultural use in the recent years for controlling Lepidopteran pests affecting solanaceous crops. The extensive use of synthetic pyrethroids like β-cyfluthrin has resulted in wide spread environmental contamination. The purpose of this study was to isolate bacteria from soil and to determine their ability to degrade β-cyfluthrin and identify the intermediates in culture broth using spectroscopy. An aerobic bacterium capable of degrading β-cyfluthrin was isolated by enrichment culture. The 16S ribosomal DNA sequence of the isolate (strain S1) had 100% identity to the sequence from Pseudomonas stutzeri. Finally products formed during degradation of β-cyfluthrin have been identified as α-cyano-4-fluoro-3-phenoxybenzyl-3(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylate (M.W. 341); 4-fluoro-3-phenoxy-α-cyanobenzyl alcohol (M.W. 243) and 3(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanecarboxylic acid (M.W. 208).

The impact of seed dressing and standing crop treatment (SC) with chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro pyridyl) phosphorothioate] and quinalphos [O,O-diethyl O-quinoxalin-2-yl phosphorothioate] on the oxidative capability of the soils of two semi-arid regions of tropical India were studied by monitoring their dehydrogenase activities (DHA) and capacities for reduction of iron (Fe3+) for three consecutive crop seasons. In the sandy loam, the metabolites of quinalphos inhibited both reduction of Fe3+ and DHA whereas chlorpyrifos was found stimulatory. The metabolites of chlorpyrifos namely 3,5,6-trichloro-2-pyridinol (TCP) and 3,5,6-trichloro-2-methoxy pyridine (TMP) stimulated DHA but were significantly inhibitory to reduction of Fe3+. The stimulatory effect of TCP and TMP suggested their utilization as substrates by soil microbes. In the loamy sand, chlorpyrifos and quinalphos inhibited the overall DHA within a field but stimulated DHA of the rhizospheric microbes. Standing crop treatments with quinalphos and chlorpyrifos caused prolonged inhibitory effects on reduction of Fe3+ while seed treatments caused fluxes of shorter durations. The inhibitory effects on reduction of Fe3+ were more prolonged with chlopyrifos than with quinalphos. Pesticide treatments at the recommended doses increased the yield of groundnut (Arachis hypogaea L.) pods that had no residual pesticides. Adverse effects of agronomic importance on DHA and reduction of Fe3+ were not observed during this study.

Esterase enzyme was isolated from goat intestine and partially purified to explore whether it can degrade β-cyfluthrin, a synthetic pyrethroid insecticide. The products of the reaction were identified in order to propose its path of degradation to innocuous non-toxic compounds. This is the first report for testing the suitability of such esterase enzyme for degrading a synthetic pyrethroid insecticide.

Effects of seed treatments with chlorpyrifos [5 g of active ingredient (ai) kg(-1) of seed] and quinalphos (6.25 g of ai kg(-1) of seed) and standing crop treatments with chlorpyrifos (800 g of ai ha(-1)) and quinalphos (1000 g of ai ha(-1)) on arginine deamination and mineralizable nitrogen were monitored, in the sandy loam and loamy sand soils of two tropical semiarid fields, for three consecutive crop seasons. The arginine ammonification activity of rhizospheric microbes was inhibited after seed treatment with chlorpyrifos and quinalphos and their principal metabolites, 3,5,6-trichloro-2-pyridinol (TCP) and 3,5,6-trichloro-2-methoxypyridine (TMP) and 2-hydroxyquinoxaline and quinoxaline-2-thiol, respectively. Quinalphos produced transient inhibitions, whereas chlorpyrifos and its metabolites (TCP and TMP) exerted a greater inhibition in both loamy sand and sandy loam soils. Arginine ammonification by nonrhizospheric microbes was stimulated by standing crop treatments with both pesticides. In the loamy sand soil, the parent compounds stimulated rhizospheric N-mineralization, whereas the metabolites were inhibitory. However, nonrhizospheric N-mineralization was inhibited by both chlorpyrifos and quinalphos and stimulated by their metabolites. A higher magnitude of inhibition of arginine deamination in the loamy sand than in the sandy loam soil could be due to greater bioavailability of the pesticides in the former, resulting from lesser sorption of the pesticides due to alkalinity of the soil and its low content of clay and organic carbon. Although both pesticides affected mineralizable nitrogen, seed treatment with quinalphos and standing crop treatment with quinalphos and chlorpyrifos produced the most significant effects. The recommended doses of the pesticides not only efficiently controlled whitegrubs, which increased pod yields, but also left no residues in harvested kernels. They also caused no long-term inhibition of ammonification, which could have been of significant concern during the short crop period in semiarid areas where nitrogen determines plant productivity.

The dissipation of 14C carbaryl in undisturbed soil cores, and of quinalphos (25EC and 20AF) after seed and soil treatments, was investigated under field use conditions, in a semi-arid groundnut field. Residues were analyzed by TLC and HPLC and additionally by LSC for 14C carbaryl. The harvested seed kernels were also tested for the presence of insecticide residues. The movement of carbaryl was limited to 15 cm depth in the loamy sand of Jaipur and was detected till 120 days (DT50 of 14.93 days) after application. Bound residues and 1-naphthol had a DT50 of 11.45 and 13.68 days, respectively. Irrespective of the three types of soil samples investigated, the principal metabolite formed on seed and soil treatments with quinalphos, was 2-hydroxyquinoxaline. With seed treatment, a thiol metabolite of quinalphos was also detected. Higher yields of groundnut were realized with quinalphos treatments in comparison to those from control. Post-harvest, no pesticide residues were found in seeds.

The study deals with the facile synthesis of catenated nanosulfur by entrapping elemental sulfur with polyethylene glycol 400 with the help of bottom up approach. The synthesized nanosulfur was studied by transmission electron microscope (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and thermogravimetric analysis (TGA). The average size was about 35.5 ± 8.5 nm which was confirmed by TEM distribution curve fitted with Gaussian model. XRD shows that the synthesized nanosulfur was crystalline in nature. FTIR study confirmed that PEG was encapsulated over catenated nanosulfur. TGA confirmed the stability of nanosulfur up to 200 °C as there was no significant change in the differential weight with respect to temperature 200 °C. The active ingredient of this encapsulated nanosulfur was 0.62 g/g which was estimated by UHPLC.

The recently registered insecticide, imidacloprid, was applied to three vegetable crops at 20 and 40 g AI ha−1. The persistence of the parent insecticide and its translocation, along with the quantification of the metabolites formed on these crops are presented. The parent insecticide dissipated with a half-life of 3–5 days and persisted longest on mustard leaves. The detectable limit of the HPLC method was 0.01 µg g−1. The metabolites 1-(6-chloropyridin-3-yl-methyl)imidazolidin-2-one and 6-chloronicotinic acid were found to be translocated by day 10 in eggplant, cabbage leaves and mustard leaves but not in cabbage curd. The MRL of imidacloprid is not documented by the FAO/WHO on these crops and comparison of the MPI with the TMRC, calculated on the residue data generated in this study, establishes the safety of the schedule. © 2000 Society of Chemical Industry

Intensive application of organochlorine pesticides in agriculture and medicinal parasitology coupled with high stability of these pesticides in the environment resulted in their spreading all over the globe.The world over the use of HCH in agriculture has been banned . However , it is still being used in animal sheds and public health . The compulsive use of HCH is the low cost of the insecticide. Its use has recently been banned and the use of lindane is being favoured in agriculture. Lindane is the active constituent of HCH and its use should be beneficial in terms of insect control and it will not pose any environmental problem due to the accumulation of the more persistent beta isomer of HCH. Though, HCH is not used in many countries there are reports of its residues in the environment, probably caused by long range transport from other areas (Cleeman et.al 1995 ). Monitoring of vegetables ( Lal et al. 1969; Mukherjee and Gopal 1996), milk (Mukherjee and Gopal 1993) ,drinking and ground water (Gopal and Mukherjee,1999; Allchin 1991) 1 lakes ( Dua et al. 1998), fishes ((Mugachia et al.1992) have recorded the presence of HCH residues . Because of the ability of HCH to dissolve in fats they get accumulated in the adipose tissues of animals and men (Waliszewskei et.al.1995) and have also been detected in breast milk ( Barkatina et .al .1998) .

Two soil fungi, namely Aspergillus niger and Trichoderma viride were evaluated for the degradation of chlorpyrifos. T. viride has been found to be more active, 95.7% of chlorpyrifos degraded in the presence of T. viride as compared to 72.3% in A. niger by day—14. The toxic metabolite of chlorpyrifos, 3, 5, 6‐trichloropyridinol was not detected during the 14‐day incubation period.

Fluvalinate was applied on chickpea crop at (i) 0.056, (ii) 0.112 and (iii) 0.56 kg a.i. ha‐1 to evaluate its rate of dissipation. Two major degradation products of fluvalinate formed on the crop were identified and characterised as phenoxybenzoic acid and 2‐[2‐chloro‐4‐(trifluoromethyl)anilino]‐3‐methylbutanoic acid. They were estimated in day‐5 and day‐10 samples of chickpea crop as their methyl esters by gas liquid chromatography.

Phytotoxic and agro beneficial properties of antimicrobially efficient Sulfur nanoparticles (SNPs) and ZnO nanoparticles (ZNPs) were evaluated on Mung (Vigna radiata). Mung seeds were germinated with an increasing concentration gradient of nanoparticles. The extent of phtotoxicity were assessed depending upon the effect of used nanoparticles on physical factors (relative root and shoot length, dry weight and area of leaves), photosynthetic pigments (chlorophyll, carotene and xanthophyll content) and mitochondrial stress indicator level (thiol), A simultaneous study was undertaken to understand the effect of SNPs and ZNPs on overall plant growth and nutrition. The nutritive values of nanoparticles were determined in terms of total lipid and protein content. All the aforementioned biochemical assays were performed in triplicate for statistical viability.

Thiacloprid is a systemic neonicotinoid. The study hypothesized that difference may be seen in the rate of dissipation of thiacloprid when applied on non-transgenic and transgenic cabbage. Thiacloprid was estimated by HPLC. Half life of thiacloprid in transgenic as well as in normal cabbage ranged between 12.3–13.1 days in two doses of application. Under field condition, after 15 days, 59.2 % and 54.3 % dissipation was recorded at lower and higher rates of application in transgenic cabbage, where as the insecticide dissipated 57.5 % and 59.1 % for single dose and double dose application, respectively in non-transgenic cabbage. The study establishes that there is no significant difference in dissipation of a systemic pesticide in transgenic versus non-transgenic cabbage. Decontamination of thiacloprid contaminated cabbage was carried out by different chemical treatments. The application of 0.5 % NaHCO3 (an edible alkali) may be recommended for decontamination. Thiacloprid residues in the day-3 field samples of cabbage could be reduced below Japanese MRL (1.0 mg kg−1) by treating with 0.5 % NaHCO3 solution for 1 h.

Crop losses due to bacterial pathogens are a major global concern. Most of the available pesticides for these pathogens suffer from various drawbacks such as complicated synthesis, high cost, high toxicity, pesticide resistance and environmental hazards. To overcome these drawbacks, the present study was undertaken to find a potent bactericide. Therefore, a series of compounds comprising bioactive furyl and oxazolone rings was synthesized under microwave irradiation and screened for in vitro antibacterial activity. The reactions were completed in fewer than 2 minutes with minimal use of solvents and resulted in high yields. These compounds were screened for antibacterial activity against plant pathogens, Xanthomonas oryzae, Ralstonia solanacearum and nitrifying bacteria, Nitrosomonas species under laboratory conditions. Five compounds were active as antibacterial agents against Xanthomonas oryzae and Ralstonia solanacearum. However, all compounds were effective against the Nitrosomonas species and the best one was 2-furyl-4-(3-methoxy-4-hydroxybenzylidene)-5(4H)-oxazolone. The study revealed the fast and environmentally friendly synthesis of bioactive title compounds, which also hold promise to be used as prototypes for the discovery of potent analogues.

The organochlorine insecticide endosulfan is a mixture of two stereoisomers, alpha and beta. The degradation of the more persistent beta isomer was shown using the soil microorganism Aspergillus niger. The relatively rapid rate of degradation of beta‐endosulfan as compared to control, formation of endosulfan diol and absence of formation of the toxic metabolite endosulfan sulfate suggest the possibility of developing a non‐chemical method for degrading endosulfan.

The pure individual stereoisomers of endosulfan, alpha-endosulfan and beta-endosulfan, were applied as emulsifiable concentrates to chickpea crop at the rate of 175 g a.i. ha -1 and 50 g a.i. ha -1 , respectively. The dissipation rate of these isomers revealed that alpha-endosulfan interconverted to beta-endosulfan in minor quantities, while it was converted into endosulfan sulfate on chickpea leaves in significant amounts. On application, beta-endosulfan was converted to endosulfan sulfate and alpha-endosulfan in relatively smaller amounts. The study indicates that the beta stereoisomer of endosulfan is more persistent because it is resistant to interconversion and metabolic change

A field trial was conducted to study (i) whether there is interconversion of stereoisomers of hexachlorocyclohexane (HCH) on a plant and (ii) the rate of dissipation of lindane on chickpea in a sub-tropical climate. The lack of formation of the beta and delta isomers on application of pure alpha- or gamma-HCH showed that these stereoisomers of HCH did not interconvert on chickpea. The residues of the alpha and gamma isomers dissipated rapidly on chickpea leaves with half-lives of three and four days respectively (.)

Extractable residues of endosulfan stereoisomers and its toxic metabolite, endosulfan sulfate, on a vegetable, an oilseed and a pulse crop were determined by gas-liquid chromatography. The study revealed that the alpha isomer degraded faster than the beta isomer. Beta-endosulfan accumulated during the first three days following the treatment. Endosulfan sulfate residues appeared a few days after application and decreased with time. The total endosulfan residues in the seeds from treated mustard ranged from 0.08 to 0.12 mg kg -1 and were at or below the limit of determination (0.02 mg kg -1 ) in chickpea seeds following harvest

Analysis of selenium solubility in solutions of iodine in carbon disulfide shows that selenium iodides are formed, according to the equilibrium nSe+I 2 =SenI 2 . Selenium-77 NMR spectra of these solutions exhibit 4 principal peaks, which are assigned to Se 3 I 2 (α-Se and β-Se), Se 2 I 2 , and SeI 2 , as supported by their concentration dependence, chemical shifts, and half-height line widths. The main selenium iodide formed is Se 2 I 2 .

The persistence patterns of three synthetic pyrethroids—fenvalerate, tau-fluvalinate, lambda-cyhalothrin—and an organophosphorus insecticide, monocrotophos, on eggplant (Solanum melongena L.) have been evaluated. The extractable residues ranged from 0.05 to 0.45, 0.01 to 0.40, 0.003 to 0.09 and 0.09 to 0.32 μg g−1 for fenvalerate, tau-fluvalinate, lambda-cyhalothrin and monocrotophos, respectively. Fenvalerate was the most persistent among the four, followed by monocrotophos, lambda-cyhalothrin and tau-fluvalinate. The Maximum Residue Limit (MRL) of these pesticides on S. melongena has not yet been documented. The present data may be useful for establishing MRL and assessing the amount of pesticide residues in this vegetable.

Indoxacarb was applied at 75 and 150 g a.i. ha(-1) for two years to an eggplant (Solanum melongena L.) crop grown in the field plots in order to evaluate its efficacy for management of the lepidopteron pest, shoot and fruit borer. The residues of the insecticide were quantified by high-pressure liquid chromatography (HPLC). The mean initial deposits of indoxacarb on eggplant fruits were found to be 2.60-2.634 mg kg(-1) and 3.64-3.68 mg kg(-1) from the two rates of applications, respectively. They declined with time and reached to non-detectable (< 0.02 mg kg(-1)) after 15-20 d. Residues dissipated with a half-life of 3.0-3.8 d from both first and second-year application. A 3 d waiting period for harvest of fruits after insecticide application and processing resulted in the residue levels that were below the Codex maximum residue limit (MRL) of 0.5 mg kg(-1) thereby achieving a maximum safety and minimum risk to consumers. The best combination of chemicals for decontamination of indoxacarb was found to be by washing with a mixture of alkali and potassium permanganate (KMnO(4)) thereby resulting in the removal of 67.5% and 59.2 % residues for 5 and 10 microg g(-1) spiking doses, respectively. Major products formed on reaction of indoxacarb with alkali were identified by electron spray ionization chromatography/mass spectrometry (ESI/MS). The per cent reduction on the weight and number basis of treated eggplant plots were compared to those observed in control plots to demonstrate the effectiveness of indoxacarb treatment on shoot and fruit borer population.

Studies were conducted to analyze the residue of commonly used pesticides viz. methyl parathion, chloropyrifos, endosulfan, cypermethrin, fenvalerate, carbendazim, imidacloprid and carbaryl in mango, Dashehari variety, integrated pest management (IPM) and non-IPM samples were collected from the IPM and non-IPM orchards, Lucknow, India. We also present a method for the simultaneous determination of these pesticides in mango samples. Residues of methyl parathion, chloropyriphos, endosulfan, cypermethrin, fenvalerate were extracted from the samples with acetone: cyclohexane: ethyl acetate in the ratio 2:1:1 followed by cleanup using neutral alumina. Analysis was performed by gas chromatography-electron capture detector (GC-ECD) with a megabore column (OV-1). Residues of carbendazim, imidacloprid and carbaryl were extracted with acetone and after cleanup, analysis was performed by high performance liquid chromatography (HPLC) using photo diode array (PDA) detector. Recoveries of all the pesticides ranged between 72.7-110.6%, at 0.1 and 1.0 microg g(-1) level of fortification. The residues detected in non-IPM samples of mango were found to be below the prescribed limits of maximum residue limit (MRL) while IPM samples were free from pesticide residues.

The paper presents a method for residue analysis of flubendiamide in rice (Oryza sativa), which includes improved extraction, cleanup and determination of flubendiamide in rice seeds, husk and straw by using LC with UV detection. Safety evaluation of this insecticide in rice has been carried out after applying its soluble concentrate (SC) formulation at recommended dose (30 g a.i. ha(-1)) and double of the recommended dose (60 g a.i. ha(-1)) on rice crop. MRL of flubendiamide on rice grain can be proposed as 0.2 mg kg(-1).

Iprodione (3-(3,5-dichlorophenyl)-N-isopropyl-2,4-dioxoimidazolidine-1-carboxamide) bio-assayed against fungi Alternaria brassicicola and Sclerotinia sclerotiorum was found to be highly effective for inhibiting these desapers. Inhibition of A. brassicicola was 100% up to the dose of 75 ppm and for S. sclerotiorum there was 50% inhibition for the same concentration. Formulation of the pesticide was applied @ 500 and 1000 g. a.i./ha on the cabbage crop grown in the fields. Residues in the edible sample of cabbage were analyzed by gas choromatography for the fungicide and its metabolites. The dissipation of residues of the fungicide and its bio-efficacy against two fungi are presented. It dissipated from 3.72 to 0.072 microg/g on cabbage head by 15 days after treatment. The EC50 values of iprodione were found to be 11.5 ppm and 79.4 ppm for A. brassicicola and S. sclerotiorum, respectively. Half-life of iprodione was found to be 3 days for both cabbage head and leaves. The compatibility of the fungicide with a bio agent, T. harzianum was also studied and these two were not found to be compatible.

A simplified method for estimating extractable residues of oxydemeton methyl (demeton-S-methyl sulphoxide) as its sulphone from crop matrix was developed. Oxydemeton methyl was oxidised with meta-chloroperbenzoic acid (MCPBA) to yield the oxydemeton methyl sulphone (demeton-S-methyl sulphone). The identity of the product was confirmed by IR, H-NMR and mass spectroscopy. The average percent recovery of the procedure is 90–95%. The limit of determination is 0.05 μg/ml.