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Papers by A SUGANTHI

Research paper thumbnail of Determination of Chlorantraniliprole for Managing Helicoverpa Armigera and Spodoptera Litura in Cotton Ecosystem

Research paper thumbnail of Dissipation Kinetics and Dietary Risk Assessment of Chlorantraniliprole and Fipronil Residues on Moringa Oleifera Pods Using Lc-Ms/Ms

Moringa (Moringa oleifera, F: Moringaceae), popularly referred to as the 'drumstick tree' or 'hor... more Moringa (Moringa oleifera, F: Moringaceae), popularly referred to as the 'drumstick tree' or 'horse-radish tree' and colloquially known as 'Muringai' in Tamil, is a highly sought-after crop in the Indian subcontinent for its nutritious leaves. A modified QuEChERS method was developed for accurate and simultaneous detection and quantification the residues of the two insecticides from Moringa leaves using LCÀMS/MS. The method offered high degree of linearity (r 2 > 0.99), recovery (70À90 %), and precision (<20%) for analysis of both the insecticides. The matrix interferences, which is a prevalent complication in the analysis of leafy and dark-pigmented matrices, was suppressed by the developed method. Three decontaminating reagents of household importance À sodium chloride, acetic acid and sodium bicarbonate À were tested for their efficacy to reduce the insecticide residue on the Moringa leaves by washing. The combination of sodium bicarbonate carbonate and sodium chloride at 5% each, was found to be the more efficacious among the treatments lowering the chlorantraniliprole residues up to 85.71% and 71.79% in case of X and 2X doses of chlorantraniliprole while the same combination lowered the concentration of fipronil to 67.95 % and 61.15 % for the two doses of the insecticide sprayed on the Moringa leaves. Moringa is an underexploited crop which has immense potential for addressing the nutritional security in the country as well as for export owing to the demand. This work attempts to address the unscientific management practices in on the crop as well as to suggest measures for minimizing the current residue loads by taking the first stride towards developing regulatory limits, which could benefit the researchers and policy makers.

Research paper thumbnail of Dissipation kinetics, effect of household processing, and dietary risk assessment of the insecticide chlorantraniliprole residue in bitter gourd and soil

ENTOMON

A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to deter... more A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to determine the insecticide chlorantraniliprole residues in bitter gourd fruit, juice, and soil, according to the SANTE guidelines. A linear curve was obtained (R2 > 0.99) with LOD and LOQ at 0.003 mg kg-1 and 0.01 mg kg-1. The accuracy (87–102%) and precision (RSD <5%) of the method was found to be satisfactory. The dissipation pattern of chlorantraniliprole 18.5% SC was studied by spraying twice at ten days intervals, at the recommended dose (X) (25 g a.i. ha-1), and double the recommended dose (2X) (50 g a.i. ha-1). The initial deposit on bitter gourd was 0.72 and 1.41 mg kg-1 and residues persisted up to 15 and 20 days with a half-life of 2.44 and 2.79 days at X and 2X doses, respectively. Simple decontamination techniques were found to reduce residues to the extent of 30 to 80 per cent. The reduction of chlorantraniliprole residues in bitter gourd juice was 40-50 per cent by differe...

Research paper thumbnail of Dissipation kinetics, decontamination and dietary risk assessment of imidacloprid residue in bitter gourd and soil

Journal of Applied and Natural Science

Imidacloprid is a broad-spectrum neonicotinoid class insecticide with systemic action, widely use... more Imidacloprid is a broad-spectrum neonicotinoid class insecticide with systemic action, widely used on vegetables in India for the management of sucking insect pests. The overall pesticide usage profile in gourds growing districts of Tamil Nadu showed that imidacloprid as the most commonly used insecticide. The present study aimed to develop and validate an analytical approach for detecting imidacloprid and 6-chloronicotinic acid residues in bitter gourd fruit, juice and soil using LC-EI-MS (liquid chromatography coupled with electron ionization mass spectrometry) was undertaken. The persistence pattern, effect of household processing and risk assessment of imidacloprid on bitter gourd was studied by conducting field trials at single and double doses of 20 and 40 g a.i ha-1. Calibration curves showed a good linear relationship (r2>0.99) with the concentrations (0.0025–0.5 µg mL-1) of imidacloprid and 6-chloronicotinic acid. The limit of detection and quantification of the method w...

Research paper thumbnail of Dissipation Kinetics, Effect of Household Processing, and Dietary Risk Assessment of Chlorantraniliprole Residue in Bitter Gourd and Soil

A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to deter... more A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to determine chlorantraniliprole residues in bitter gourd fruit, juice, and soil, according to the SANTE guidelines. A linear curve was obtained (R2 > 0.99) with LOD and LOQ at 0.003 mg kg-1 and 0.01 mg kg-1. The accuracy (87–102%) and precision (RSD <5%) of the method was found to be satisfactory. The dissipation pattern of chlorantraniliprole 18.5% SC was studied by spraying twice at ten days intervals, at the recommended dose (X) (25 g a.i. ha-1), and double the recommended dose (2X) (50 g a.i. ha-1). The initial deposit on bitter gourd was 0.72 and 1.41 mg kg-1 and residues persisted up to 15 and 20 days with a half-life of 2.44 and 2.79 days at X and 2X doses, respectively. Simple decontamination techniques were found to reduce residues to the extent of 30 to 80 per cent. The reduction of chlorantraniliprole residues in bitter gourd juice was 40-50 per cent by different washing techni...

Research paper thumbnail of Impact of Neonicotinoid Insecticides on the Foraging Activity of Indian Honey Bee, Apiscerana indica (Fab.) in the Cotton Ecosystem

Madras Agricultural Journal

Indian honey bees are the important managed pollinators of several agricultural and horticultural... more Indian honey bees are the important managed pollinators of several agricultural and horticultural crops in India. At present, bee colony decline is the biggest crisis amongbeekeepers. The use of neonicotinoid insecticides is considered the prime factor, and they were found to cause a direct impact on bees by mortality and indirectly impair the foraging behavior of bees. Hence, the study aimed to assess the impact of neonicotinoids on the foraging activity of Indian honey bees. The neonicotinoids viz., imidacloprid 17.8 SL, clothianidin 50 WDG, thiamethoxam 25 WG, and thiacloprid 21.7 SC, along with organophosphate dimethoate 30 EC (chemical check) and control (no spray) were sprayed at field recommended doses on cotton crop. Foraging activity of the bees,viz.,incoming foragers with nectar and pollen load and outgoing foragers were counted at the hive entrance during the morning (09.00-11.00), afternoon (13.00-15.00), and evening (16.00-18.00) hours of the day. The data were recorded...

Research paper thumbnail of Effect of Decontamination and Processing on Insecticide Residues in Grape (Muscat Hamburg)

Field and laboratory experiments were conducted to study the effect of simple decontamination met... more Field and laboratory experiments were conducted to study the effect of simple decontamination methods and processing on imidacloprid, dimethoate, and emamectin benzoate residues in grapes and their processed products using Liquid-Chromatograph Mass Spectrometer validated method. Among the decontamination methods evaluated, sodium chloride (2%) solution was found effective and contributed to the reduction of imidacloprid (77.55%), dimethoate (83.27%) and emamectin benzoate (77.28%) residues in mature grapes. Grapes were processed into various products viz., fresh juice, squash and raisin as per standard effective steps for each product. Based on decontamination experiment findings, washing with sodium chloride (2%) solution was included as an additional step in the standard protocol and has resulted in substantial removal of surface residues of selected insecticides. The processing factor calculated was less than one for all the products.

Research paper thumbnail of Method Validation, Dissipation and Decontamination of Flubendiamide Residues in Lettuce using LC/MS/MS

Pesticide Research Journal, 2019

A method for determining flubendiamide residues in lettuce using LCMS/MS with negative electron s... more A method for determining flubendiamide residues in lettuce using LCMS/MS with negative electron spray ionization was developed and used for its residue analysis. Samples were extracted in acetonitrile and cleaned up by dispersive solid phase extraction with recovery of 70 to 120 per cent at RSD < 20 per cent. The residues dissipated on 25 and 30 d of application of flubendiamide at 24 and 48 g a.i. ha-1 respectively on lettuce. Tamarind water washing was found very effective for decontamination of flubendiamide residues from iceberg lettuce. It removed 91.62 and 82.11 per cent of residues at the recommended and double the recommended doses.

Research paper thumbnail of Impact of drought stress on simultaneously occurring pathogen infection in field-grown chickpea

Scientific Reports, 2019

Drought stress and pathogen infection simultaneously occur in the field. In this study, the inter... more Drought stress and pathogen infection simultaneously occur in the field. In this study, the interaction of these two stresses with chickpea, their individual and combined effect and the net impact on plant growth and yield traits were systematically assessed under field and confined pot experiments. The field experiments were conducted for four consecutive years from 2014–15 to 2017–18 at different locations of India. Different irrigation regimes were maintained to impose mild to severe drought stress, and natural incidence of the pathogen was considered as pathogen stress. We observed an increased incidence of fungal diseases namely, dry root rot (DRR) caused by Rhizoctonia bataticola, black root rot (BRR) caused by Fusarium solani under severe drought stress compared to well-irrigated field condition. Similar to field experiments, pot experiments also showed severe disease symptoms of DRR and BRR in the presence of drought compared to pathogen only stress. Overall, the results fro...

Research paper thumbnail of Impact of Decontamination Processes on the Reduction of Pesticide Residues in Green Chilli

Indian Journal of Entomology

This study has been designed to determine the extent of pesticide residue removal from chilli fru... more This study has been designed to determine the extent of pesticide residue removal from chilli fruits through common household practices. One time foliar application of quinalphos, profenophos, ethion, cyhalothrin, imidacloprid, and acetamiprid was done as a tank mix at recommended doses at 50% fruit formation stage. Samples were collected after 48 hr of spray, subjected to various decontamination treatments, and analysed using the validated QuEChERS method employing GC-ECD (Gas Chromatograph Electron capture detector), and Liquid Chromatograph Tandem Mass Spectrometer (LC-MS/MS). Compared to all the treatments, soaking in 5% acetic acid for one min was found to be most effective in the removal of quinalphos (23.68%), profenophos (19.47%), ethion (23.33%), and cyhalothrin (25.00%). The next best treatment was found to be soaking for one min in lukewarm water, which removed 20-30% of quinalphos, ethion, cyhalothrin, and acetamiprid residues.

Research paper thumbnail of Analysis of cyantraniliprole residues in beetroot and beet top using LC‐MS/MS, dietary exposure assessment, and evaluation of decontamination techniques

Journal of Environmental Quality

Research paper thumbnail of Acaricide Resistance in Tetranychus urticae Koch (Acari:Tetranychidae)-Global Scenario

Journal of Entomology, 2004

Research paper thumbnail of Phytochemical profile and toxicity of thyme-derived (Thymus vulgaris) essential oil against the exotic rugose spiraling whitefly (Aleurodicus rugioperculatus Martin) infesting coconut

Journal of Plantation Crops

Microwave-assisted heat extraction of thyme (Thymus vulgaris) yielded 1.64 per cent w/v of yellow... more Microwave-assisted heat extraction of thyme (Thymus vulgaris) yielded 1.64 per cent w/v of yellow to amber coloured and less viscous oil with a peculiar aroma. GC-MS analysis revealed the presence of 20 compounds, out of which thymol (51.94%), p-cymene (14.5%), γ-terpinene (10.09%), linalool (3.48%), and endo-borneol (3.95%) were the major compounds. Eggs, second instar nymphs and pupae of rugose spiraling whitefly (RSW) were subjected to contact toxicity assessment by complete immersion (dip method) in various concentrations of thyme oil. The results showed that essential oils at 0.35 per cent concentration exhibited 100 per cent mortality in the second instar nymphs. Thyme oil (0.5%) inhibited egg hatching and adult emergence to the tune of 100 per cent when the eggs and pupal stages were treated. Probit analysis indicated that the median lethal concentration (LC50) of thyme oil to eggs, second instar nymph sand pupal stages were 0.19, 0.13 and 0.21 per cent, respectively. Thyme o...

Research paper thumbnail of Bioefficacy, persistent toxicity, and persistence of translocated residues of seed treatment insecticides in maize against fall armyworm, Spodoptera frugiperda(J. E. Smith, 1797)

Crop Protection, 2022

The fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) emerged as a major threat to several... more The fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) emerged as a major threat to several maize growing countries worldwide. To manage this pest outbreak, farmers rely heavily on insecticides. Seed treatment with insecticides in maize is often the most pragmatic fall armyworm (FAW) management tactic. The aim of this work was to determine the bioefficacy, persistent toxicity, and persistence of translocated residues of insecticide seed treatments in maize used for the management of FAW. Bioefficacy of several seed treatment insecticides (Thiamethoxam, fipronil, tetraniliprole, chlorantraniliprole, cyantraniliprole + thiamethoxam, tetraniliprole + fipronil) was evaluated via foliar damage rating after crop emergence using the Tamil Nadu Agricultural University damage scoring scale. Persistent toxicity was assessed through a laboratory bioassay using the first instar larvae that fed on seed-treated maize leaves. Persistence of translocated residues was studied using Liquid Chromatography-Mass Spectrometry/Mass Spectrometry technique. Chlorantraniliprole 62.5 FS @ 6 ml kg − 1 seed provided the highest protection followed by cyantraniliprole + thiamethoxam 19.8 FS, tetraniliprole 480 FS, and tetraniliprole + fipronil 240 FS. An increase in damage rating was observed 10 and 12 days post crop emergence. at 10 and 12 days post crop emergence with treatments involving diamides, except for chlorantraniliprole. Thiamethoxam and fipronil seed treatments were ineffective in FAW larvae management. Chlorantraniliprole residues persisted for >26 days, and cyantraniliprole + thiamethoxam residues persisted for >16 days in maize seedlings. The field bioefficacy of diamide insecticides residues matched with their toxicity persistence in laboratory bioassays, revealing them as best fit seed treatments when compared with thiamethoxam and fipronil. Seed treatment in maize with these diamide insecticides will be useful up to 15 days post crop emergence in preventing FAW foliar damage.

Research paper thumbnail of Impact of Pesticide Exposure on Environment and Biodiversity: A Review

Agricultural Reviews, 2021

The use of pesticide in modern agriculture and public health sector has been increased tremendous... more The use of pesticide in modern agriculture and public health sector has been increased tremendously. Only 0.1% of pesticide applied to crops truly reaches the target, the rest of it enters into the environment. Several pesticides can persist in an ecosystem for longer periods accumulate in the body tissues of organisms and cause more health problems. Pesticide exposure generally occurs through ingestion, inhalation and skin contact or absorptions by intentionaly or unintentionaly which leads to acute and chronic health problems in non target organisms such as animals, birds, aquatic animals and human. A total of more than 100 articles related to impact of pesticide exposure were reviewed. To review the literature, we reviewed a number of studies, report and abstract between 1950 to 2020 using key words effect of pesticide on animals, birds, human, environment we used this term to search in in PubMed, ResearchGate and google scholar. Searching strategy also include cross-referencing ...

Research paper thumbnail of Flagellin and elongation factor of Bacillus velezensis (VB7) reprogramme the immune response in tomato towards the management of GBNV infection

Journal of Virological Methods, 2021

The present study investigates the reprogramming of plant defense system, upon interaction with M... more The present study investigates the reprogramming of plant defense system, upon interaction with MAMP (Microbe Associated Molecular Pattern) gene products including, flagellin (Flg) and elongation factor (EF-Tu) of Bacillus velezensis (VB7) and groundnut bud necrosis virus (GBNV) in tomato (Shivam). The MAMP gene products induced the plant defense genes including, PAL, PPO, LOX, JAR, MYC2 and PDF 1.2. Secondary metabolites of Bacillus spp. at 1000 parts per million (ppm) concentration effectively reduced GBNV symptom expression in cowpea (CO7) up to 83.1 % compared to untreated, GBNV inoculated, control. The secondary metabolites from B. velezensis (VB7) and B. licheniformis (Soya 1) reduced GBNV symptoms in cowpea (CO7) up to 1.7 lesions/cm2 leaf area compared to 8.6 lesions/cm2 in virus inoculated control. Further, field study revealed that the combined application of B. velezensis (VB7) and B. licheniformis (Soya1) at 1% (10 mL/L) as, soil and foliar application reduced the percent disease incidence (PDI) up to 10.5 (PDI) compared to 28.4 (PDI) in untreated control plants. Besides, it also improved the plant growth and yield up to 23.5 tonnes/ha compared to 13.8 tonnes/ha in untreated control.

Research paper thumbnail of Incidence of sorghum shoot fly and stem borer in forage sorghum grown under poplar, Populus deltoides Marsh. based agri-silviculture system

Journal of entomological research, 2001

Sorghum as sole crop recorded higher shoot fly and stem borer incidence than sorghum intcrcropped... more Sorghum as sole crop recorded higher shoot fly and stem borer incidence than sorghum intcrcropped with poplar tree. Among the two poplar tree systems, shoot fly incidence was found less in 15 × 2.5 m spacing than 10 × 2.5 m spacing but the reverse was true for stem borer. Within poplar systems the differences were not significant. HC 260 variety recorded higher number of egg and deadhearts due to shoot fly, and dead hearts, leaf injury and stem tunneling due to stem borer as compared to HC 171.

Research paper thumbnail of Analysis of tebuconazole residues in coconut water, kernel and leaves using LC–MS/MS

Food Chemistry, 2021

A method was validated for determining tebuconazole residues in coconut water, kernel and leaves ... more A method was validated for determining tebuconazole residues in coconut water, kernel and leaves using Liquid chromatography-Mass spectrometry/Mass spectrometry (LC-MS/MS) with electro spray ionization in positive ion mode. Samples were extracted with acetonitrile and subsequent clean-up was done using dispersive solid phase extraction. Recovery ranged between 70 and 114.39 % and the RSD was between 0.64 and 10.24 %. Root feeding studies with tebuconazole @ 5 and 10 mL/100 mL of water/tree revealed the presence of tebuconazole residues in coconut leaves until three days after treatment but dissipated to below quantifiable limit on 5th day at single dose while the residues went below quantifiable limit after 10 days at double the dose. Residues were below quantifiable limit in coconut water and kernel until three days. Data obtained from the study were used for estimating the risks associated with the exposures to tebuconazole residues in coconut.

Research paper thumbnail of Monitoring the resistance and baseline susceptibility of Plutella xylostella (L.) (Lepidoptera: Plutellidae) against spinetoram in Tamil Nadu, India

Crop Protection, 2021

Abstract Diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), is a destructive cosmo... more Abstract Diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), is a destructive cosmopolitan pest that affects cruciferous crops, and insecticides are the major tool used for control. This study aimed to evaluate the insecticide resistance status of P. xylostella collected from ten different locations of Tamil Nadu, India against a diverse group of insecticides used by farmers. The results showed that spinetoram and novaluron were highly toxic to P. xylostella with a resistance ratio of 1.89- to 13.85-fold and 5.01- to 16.93-fold, respectively, compared to a susceptible laboratory population. All field populations exhibited a low to moderate level of resistance against spinosad (2.14- to 21.78-fold), emamectin benzoate (3.74- to 41.26-fold), and indoxacarb (3.42- to 29.37-fold), whereas high levels of resistance were observed against chlorantraniliprole (36.67- to 124.72-fold), flubendiamide (12.66- to 93.63-fold), fipronil (31.99- to 156.24-fold), and cypermethrin (26.97- to174.84-fold). A significant correlation was found between the LC50 values of spinetoram and spinosad (P = 0.001). However, no significant correlation (P > 0.05) was observed between spinosyn and other insecticides suggesting a lack of cross-resistance with other groups of insecticides. The synergistic assay showed that the metabolic detoxification mechanisms may not be responsible for P. xylostella resistance against spinetoram. Hence, to prevent the development of resistance in P. xylostella, a combination of insecticides having different mechanisms of action should be used in rotation.

Research paper thumbnail of Method Validation of LC-MS/MS Analysis of Neonicotinoid Insecticides in Soil

Madras Agricultural Journal, 2017

A simple, sensitive and inexpensive analytical method was developed using solid-phase extraction... more A simple, sensitive and inexpensive analytical method was developed using solid-phase extraction for the simultaneous determination of five neonicotinoid insecticides in soil matrix using LC-MS/ MS and validated. The samples were extracted with acetonitrile and subsequent cleanup was done by dispersive solid-phase extraction (QuEChERS method). The quantification was carried out by liquid chromatography-tandem mass spectrometry with electrospray ionization source (LC-ESI-MS/MS). After the optimization of the extraction parameters, the method was validated by evaluating, linearity, limits of detection and quantification, precision (repeatability) and accuracy (recovery). Validation was based on analysis at three fortification levels and showed satisfactory recoveries (77.03 to 115.08 %) and high precision (RSDs between 2.01 to 13.83%). Low limits of detection and quantification could be achieved for all the five analytes ranging from 0.0007 to 0.002 and 0.002 to 0.008 μg/g, respectiv...

Research paper thumbnail of Determination of Chlorantraniliprole for Managing Helicoverpa Armigera and Spodoptera Litura in Cotton Ecosystem

Research paper thumbnail of Dissipation Kinetics and Dietary Risk Assessment of Chlorantraniliprole and Fipronil Residues on Moringa Oleifera Pods Using Lc-Ms/Ms

Moringa (Moringa oleifera, F: Moringaceae), popularly referred to as the 'drumstick tree' or 'hor... more Moringa (Moringa oleifera, F: Moringaceae), popularly referred to as the 'drumstick tree' or 'horse-radish tree' and colloquially known as 'Muringai' in Tamil, is a highly sought-after crop in the Indian subcontinent for its nutritious leaves. A modified QuEChERS method was developed for accurate and simultaneous detection and quantification the residues of the two insecticides from Moringa leaves using LCÀMS/MS. The method offered high degree of linearity (r 2 > 0.99), recovery (70À90 %), and precision (<20%) for analysis of both the insecticides. The matrix interferences, which is a prevalent complication in the analysis of leafy and dark-pigmented matrices, was suppressed by the developed method. Three decontaminating reagents of household importance À sodium chloride, acetic acid and sodium bicarbonate À were tested for their efficacy to reduce the insecticide residue on the Moringa leaves by washing. The combination of sodium bicarbonate carbonate and sodium chloride at 5% each, was found to be the more efficacious among the treatments lowering the chlorantraniliprole residues up to 85.71% and 71.79% in case of X and 2X doses of chlorantraniliprole while the same combination lowered the concentration of fipronil to 67.95 % and 61.15 % for the two doses of the insecticide sprayed on the Moringa leaves. Moringa is an underexploited crop which has immense potential for addressing the nutritional security in the country as well as for export owing to the demand. This work attempts to address the unscientific management practices in on the crop as well as to suggest measures for minimizing the current residue loads by taking the first stride towards developing regulatory limits, which could benefit the researchers and policy makers.

Research paper thumbnail of Dissipation kinetics, effect of household processing, and dietary risk assessment of the insecticide chlorantraniliprole residue in bitter gourd and soil

ENTOMON

A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to deter... more A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to determine the insecticide chlorantraniliprole residues in bitter gourd fruit, juice, and soil, according to the SANTE guidelines. A linear curve was obtained (R2 > 0.99) with LOD and LOQ at 0.003 mg kg-1 and 0.01 mg kg-1. The accuracy (87–102%) and precision (RSD <5%) of the method was found to be satisfactory. The dissipation pattern of chlorantraniliprole 18.5% SC was studied by spraying twice at ten days intervals, at the recommended dose (X) (25 g a.i. ha-1), and double the recommended dose (2X) (50 g a.i. ha-1). The initial deposit on bitter gourd was 0.72 and 1.41 mg kg-1 and residues persisted up to 15 and 20 days with a half-life of 2.44 and 2.79 days at X and 2X doses, respectively. Simple decontamination techniques were found to reduce residues to the extent of 30 to 80 per cent. The reduction of chlorantraniliprole residues in bitter gourd juice was 40-50 per cent by differe...

Research paper thumbnail of Dissipation kinetics, decontamination and dietary risk assessment of imidacloprid residue in bitter gourd and soil

Journal of Applied and Natural Science

Imidacloprid is a broad-spectrum neonicotinoid class insecticide with systemic action, widely use... more Imidacloprid is a broad-spectrum neonicotinoid class insecticide with systemic action, widely used on vegetables in India for the management of sucking insect pests. The overall pesticide usage profile in gourds growing districts of Tamil Nadu showed that imidacloprid as the most commonly used insecticide. The present study aimed to develop and validate an analytical approach for detecting imidacloprid and 6-chloronicotinic acid residues in bitter gourd fruit, juice and soil using LC-EI-MS (liquid chromatography coupled with electron ionization mass spectrometry) was undertaken. The persistence pattern, effect of household processing and risk assessment of imidacloprid on bitter gourd was studied by conducting field trials at single and double doses of 20 and 40 g a.i ha-1. Calibration curves showed a good linear relationship (r2>0.99) with the concentrations (0.0025–0.5 µg mL-1) of imidacloprid and 6-chloronicotinic acid. The limit of detection and quantification of the method w...

Research paper thumbnail of Dissipation Kinetics, Effect of Household Processing, and Dietary Risk Assessment of Chlorantraniliprole Residue in Bitter Gourd and Soil

A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to deter... more A single quadrupole liquid chromatography-mass spectrometry (LC-MS) method was validated to determine chlorantraniliprole residues in bitter gourd fruit, juice, and soil, according to the SANTE guidelines. A linear curve was obtained (R2 > 0.99) with LOD and LOQ at 0.003 mg kg-1 and 0.01 mg kg-1. The accuracy (87–102%) and precision (RSD <5%) of the method was found to be satisfactory. The dissipation pattern of chlorantraniliprole 18.5% SC was studied by spraying twice at ten days intervals, at the recommended dose (X) (25 g a.i. ha-1), and double the recommended dose (2X) (50 g a.i. ha-1). The initial deposit on bitter gourd was 0.72 and 1.41 mg kg-1 and residues persisted up to 15 and 20 days with a half-life of 2.44 and 2.79 days at X and 2X doses, respectively. Simple decontamination techniques were found to reduce residues to the extent of 30 to 80 per cent. The reduction of chlorantraniliprole residues in bitter gourd juice was 40-50 per cent by different washing techni...

Research paper thumbnail of Impact of Neonicotinoid Insecticides on the Foraging Activity of Indian Honey Bee, Apiscerana indica (Fab.) in the Cotton Ecosystem

Madras Agricultural Journal

Indian honey bees are the important managed pollinators of several agricultural and horticultural... more Indian honey bees are the important managed pollinators of several agricultural and horticultural crops in India. At present, bee colony decline is the biggest crisis amongbeekeepers. The use of neonicotinoid insecticides is considered the prime factor, and they were found to cause a direct impact on bees by mortality and indirectly impair the foraging behavior of bees. Hence, the study aimed to assess the impact of neonicotinoids on the foraging activity of Indian honey bees. The neonicotinoids viz., imidacloprid 17.8 SL, clothianidin 50 WDG, thiamethoxam 25 WG, and thiacloprid 21.7 SC, along with organophosphate dimethoate 30 EC (chemical check) and control (no spray) were sprayed at field recommended doses on cotton crop. Foraging activity of the bees,viz.,incoming foragers with nectar and pollen load and outgoing foragers were counted at the hive entrance during the morning (09.00-11.00), afternoon (13.00-15.00), and evening (16.00-18.00) hours of the day. The data were recorded...

Research paper thumbnail of Effect of Decontamination and Processing on Insecticide Residues in Grape (Muscat Hamburg)

Field and laboratory experiments were conducted to study the effect of simple decontamination met... more Field and laboratory experiments were conducted to study the effect of simple decontamination methods and processing on imidacloprid, dimethoate, and emamectin benzoate residues in grapes and their processed products using Liquid-Chromatograph Mass Spectrometer validated method. Among the decontamination methods evaluated, sodium chloride (2%) solution was found effective and contributed to the reduction of imidacloprid (77.55%), dimethoate (83.27%) and emamectin benzoate (77.28%) residues in mature grapes. Grapes were processed into various products viz., fresh juice, squash and raisin as per standard effective steps for each product. Based on decontamination experiment findings, washing with sodium chloride (2%) solution was included as an additional step in the standard protocol and has resulted in substantial removal of surface residues of selected insecticides. The processing factor calculated was less than one for all the products.

Research paper thumbnail of Method Validation, Dissipation and Decontamination of Flubendiamide Residues in Lettuce using LC/MS/MS

Pesticide Research Journal, 2019

A method for determining flubendiamide residues in lettuce using LCMS/MS with negative electron s... more A method for determining flubendiamide residues in lettuce using LCMS/MS with negative electron spray ionization was developed and used for its residue analysis. Samples were extracted in acetonitrile and cleaned up by dispersive solid phase extraction with recovery of 70 to 120 per cent at RSD < 20 per cent. The residues dissipated on 25 and 30 d of application of flubendiamide at 24 and 48 g a.i. ha-1 respectively on lettuce. Tamarind water washing was found very effective for decontamination of flubendiamide residues from iceberg lettuce. It removed 91.62 and 82.11 per cent of residues at the recommended and double the recommended doses.

Research paper thumbnail of Impact of drought stress on simultaneously occurring pathogen infection in field-grown chickpea

Scientific Reports, 2019

Drought stress and pathogen infection simultaneously occur in the field. In this study, the inter... more Drought stress and pathogen infection simultaneously occur in the field. In this study, the interaction of these two stresses with chickpea, their individual and combined effect and the net impact on plant growth and yield traits were systematically assessed under field and confined pot experiments. The field experiments were conducted for four consecutive years from 2014–15 to 2017–18 at different locations of India. Different irrigation regimes were maintained to impose mild to severe drought stress, and natural incidence of the pathogen was considered as pathogen stress. We observed an increased incidence of fungal diseases namely, dry root rot (DRR) caused by Rhizoctonia bataticola, black root rot (BRR) caused by Fusarium solani under severe drought stress compared to well-irrigated field condition. Similar to field experiments, pot experiments also showed severe disease symptoms of DRR and BRR in the presence of drought compared to pathogen only stress. Overall, the results fro...

Research paper thumbnail of Impact of Decontamination Processes on the Reduction of Pesticide Residues in Green Chilli

Indian Journal of Entomology

This study has been designed to determine the extent of pesticide residue removal from chilli fru... more This study has been designed to determine the extent of pesticide residue removal from chilli fruits through common household practices. One time foliar application of quinalphos, profenophos, ethion, cyhalothrin, imidacloprid, and acetamiprid was done as a tank mix at recommended doses at 50% fruit formation stage. Samples were collected after 48 hr of spray, subjected to various decontamination treatments, and analysed using the validated QuEChERS method employing GC-ECD (Gas Chromatograph Electron capture detector), and Liquid Chromatograph Tandem Mass Spectrometer (LC-MS/MS). Compared to all the treatments, soaking in 5% acetic acid for one min was found to be most effective in the removal of quinalphos (23.68%), profenophos (19.47%), ethion (23.33%), and cyhalothrin (25.00%). The next best treatment was found to be soaking for one min in lukewarm water, which removed 20-30% of quinalphos, ethion, cyhalothrin, and acetamiprid residues.

Research paper thumbnail of Analysis of cyantraniliprole residues in beetroot and beet top using LC‐MS/MS, dietary exposure assessment, and evaluation of decontamination techniques

Journal of Environmental Quality

Research paper thumbnail of Acaricide Resistance in Tetranychus urticae Koch (Acari:Tetranychidae)-Global Scenario

Journal of Entomology, 2004

Research paper thumbnail of Phytochemical profile and toxicity of thyme-derived (Thymus vulgaris) essential oil against the exotic rugose spiraling whitefly (Aleurodicus rugioperculatus Martin) infesting coconut

Journal of Plantation Crops

Microwave-assisted heat extraction of thyme (Thymus vulgaris) yielded 1.64 per cent w/v of yellow... more Microwave-assisted heat extraction of thyme (Thymus vulgaris) yielded 1.64 per cent w/v of yellow to amber coloured and less viscous oil with a peculiar aroma. GC-MS analysis revealed the presence of 20 compounds, out of which thymol (51.94%), p-cymene (14.5%), γ-terpinene (10.09%), linalool (3.48%), and endo-borneol (3.95%) were the major compounds. Eggs, second instar nymphs and pupae of rugose spiraling whitefly (RSW) were subjected to contact toxicity assessment by complete immersion (dip method) in various concentrations of thyme oil. The results showed that essential oils at 0.35 per cent concentration exhibited 100 per cent mortality in the second instar nymphs. Thyme oil (0.5%) inhibited egg hatching and adult emergence to the tune of 100 per cent when the eggs and pupal stages were treated. Probit analysis indicated that the median lethal concentration (LC50) of thyme oil to eggs, second instar nymph sand pupal stages were 0.19, 0.13 and 0.21 per cent, respectively. Thyme o...

Research paper thumbnail of Bioefficacy, persistent toxicity, and persistence of translocated residues of seed treatment insecticides in maize against fall armyworm, Spodoptera frugiperda(J. E. Smith, 1797)

Crop Protection, 2022

The fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) emerged as a major threat to several... more The fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) emerged as a major threat to several maize growing countries worldwide. To manage this pest outbreak, farmers rely heavily on insecticides. Seed treatment with insecticides in maize is often the most pragmatic fall armyworm (FAW) management tactic. The aim of this work was to determine the bioefficacy, persistent toxicity, and persistence of translocated residues of insecticide seed treatments in maize used for the management of FAW. Bioefficacy of several seed treatment insecticides (Thiamethoxam, fipronil, tetraniliprole, chlorantraniliprole, cyantraniliprole + thiamethoxam, tetraniliprole + fipronil) was evaluated via foliar damage rating after crop emergence using the Tamil Nadu Agricultural University damage scoring scale. Persistent toxicity was assessed through a laboratory bioassay using the first instar larvae that fed on seed-treated maize leaves. Persistence of translocated residues was studied using Liquid Chromatography-Mass Spectrometry/Mass Spectrometry technique. Chlorantraniliprole 62.5 FS @ 6 ml kg − 1 seed provided the highest protection followed by cyantraniliprole + thiamethoxam 19.8 FS, tetraniliprole 480 FS, and tetraniliprole + fipronil 240 FS. An increase in damage rating was observed 10 and 12 days post crop emergence. at 10 and 12 days post crop emergence with treatments involving diamides, except for chlorantraniliprole. Thiamethoxam and fipronil seed treatments were ineffective in FAW larvae management. Chlorantraniliprole residues persisted for >26 days, and cyantraniliprole + thiamethoxam residues persisted for >16 days in maize seedlings. The field bioefficacy of diamide insecticides residues matched with their toxicity persistence in laboratory bioassays, revealing them as best fit seed treatments when compared with thiamethoxam and fipronil. Seed treatment in maize with these diamide insecticides will be useful up to 15 days post crop emergence in preventing FAW foliar damage.

Research paper thumbnail of Impact of Pesticide Exposure on Environment and Biodiversity: A Review

Agricultural Reviews, 2021

The use of pesticide in modern agriculture and public health sector has been increased tremendous... more The use of pesticide in modern agriculture and public health sector has been increased tremendously. Only 0.1% of pesticide applied to crops truly reaches the target, the rest of it enters into the environment. Several pesticides can persist in an ecosystem for longer periods accumulate in the body tissues of organisms and cause more health problems. Pesticide exposure generally occurs through ingestion, inhalation and skin contact or absorptions by intentionaly or unintentionaly which leads to acute and chronic health problems in non target organisms such as animals, birds, aquatic animals and human. A total of more than 100 articles related to impact of pesticide exposure were reviewed. To review the literature, we reviewed a number of studies, report and abstract between 1950 to 2020 using key words effect of pesticide on animals, birds, human, environment we used this term to search in in PubMed, ResearchGate and google scholar. Searching strategy also include cross-referencing ...

Research paper thumbnail of Flagellin and elongation factor of Bacillus velezensis (VB7) reprogramme the immune response in tomato towards the management of GBNV infection

Journal of Virological Methods, 2021

The present study investigates the reprogramming of plant defense system, upon interaction with M... more The present study investigates the reprogramming of plant defense system, upon interaction with MAMP (Microbe Associated Molecular Pattern) gene products including, flagellin (Flg) and elongation factor (EF-Tu) of Bacillus velezensis (VB7) and groundnut bud necrosis virus (GBNV) in tomato (Shivam). The MAMP gene products induced the plant defense genes including, PAL, PPO, LOX, JAR, MYC2 and PDF 1.2. Secondary metabolites of Bacillus spp. at 1000 parts per million (ppm) concentration effectively reduced GBNV symptom expression in cowpea (CO7) up to 83.1 % compared to untreated, GBNV inoculated, control. The secondary metabolites from B. velezensis (VB7) and B. licheniformis (Soya 1) reduced GBNV symptoms in cowpea (CO7) up to 1.7 lesions/cm2 leaf area compared to 8.6 lesions/cm2 in virus inoculated control. Further, field study revealed that the combined application of B. velezensis (VB7) and B. licheniformis (Soya1) at 1% (10 mL/L) as, soil and foliar application reduced the percent disease incidence (PDI) up to 10.5 (PDI) compared to 28.4 (PDI) in untreated control plants. Besides, it also improved the plant growth and yield up to 23.5 tonnes/ha compared to 13.8 tonnes/ha in untreated control.

Research paper thumbnail of Incidence of sorghum shoot fly and stem borer in forage sorghum grown under poplar, Populus deltoides Marsh. based agri-silviculture system

Journal of entomological research, 2001

Sorghum as sole crop recorded higher shoot fly and stem borer incidence than sorghum intcrcropped... more Sorghum as sole crop recorded higher shoot fly and stem borer incidence than sorghum intcrcropped with poplar tree. Among the two poplar tree systems, shoot fly incidence was found less in 15 × 2.5 m spacing than 10 × 2.5 m spacing but the reverse was true for stem borer. Within poplar systems the differences were not significant. HC 260 variety recorded higher number of egg and deadhearts due to shoot fly, and dead hearts, leaf injury and stem tunneling due to stem borer as compared to HC 171.

Research paper thumbnail of Analysis of tebuconazole residues in coconut water, kernel and leaves using LC–MS/MS

Food Chemistry, 2021

A method was validated for determining tebuconazole residues in coconut water, kernel and leaves ... more A method was validated for determining tebuconazole residues in coconut water, kernel and leaves using Liquid chromatography-Mass spectrometry/Mass spectrometry (LC-MS/MS) with electro spray ionization in positive ion mode. Samples were extracted with acetonitrile and subsequent clean-up was done using dispersive solid phase extraction. Recovery ranged between 70 and 114.39 % and the RSD was between 0.64 and 10.24 %. Root feeding studies with tebuconazole @ 5 and 10 mL/100 mL of water/tree revealed the presence of tebuconazole residues in coconut leaves until three days after treatment but dissipated to below quantifiable limit on 5th day at single dose while the residues went below quantifiable limit after 10 days at double the dose. Residues were below quantifiable limit in coconut water and kernel until three days. Data obtained from the study were used for estimating the risks associated with the exposures to tebuconazole residues in coconut.

Research paper thumbnail of Monitoring the resistance and baseline susceptibility of Plutella xylostella (L.) (Lepidoptera: Plutellidae) against spinetoram in Tamil Nadu, India

Crop Protection, 2021

Abstract Diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), is a destructive cosmo... more Abstract Diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), is a destructive cosmopolitan pest that affects cruciferous crops, and insecticides are the major tool used for control. This study aimed to evaluate the insecticide resistance status of P. xylostella collected from ten different locations of Tamil Nadu, India against a diverse group of insecticides used by farmers. The results showed that spinetoram and novaluron were highly toxic to P. xylostella with a resistance ratio of 1.89- to 13.85-fold and 5.01- to 16.93-fold, respectively, compared to a susceptible laboratory population. All field populations exhibited a low to moderate level of resistance against spinosad (2.14- to 21.78-fold), emamectin benzoate (3.74- to 41.26-fold), and indoxacarb (3.42- to 29.37-fold), whereas high levels of resistance were observed against chlorantraniliprole (36.67- to 124.72-fold), flubendiamide (12.66- to 93.63-fold), fipronil (31.99- to 156.24-fold), and cypermethrin (26.97- to174.84-fold). A significant correlation was found between the LC50 values of spinetoram and spinosad (P = 0.001). However, no significant correlation (P > 0.05) was observed between spinosyn and other insecticides suggesting a lack of cross-resistance with other groups of insecticides. The synergistic assay showed that the metabolic detoxification mechanisms may not be responsible for P. xylostella resistance against spinetoram. Hence, to prevent the development of resistance in P. xylostella, a combination of insecticides having different mechanisms of action should be used in rotation.

Research paper thumbnail of Method Validation of LC-MS/MS Analysis of Neonicotinoid Insecticides in Soil

Madras Agricultural Journal, 2017

A simple, sensitive and inexpensive analytical method was developed using solid-phase extraction... more A simple, sensitive and inexpensive analytical method was developed using solid-phase extraction for the simultaneous determination of five neonicotinoid insecticides in soil matrix using LC-MS/ MS and validated. The samples were extracted with acetonitrile and subsequent cleanup was done by dispersive solid-phase extraction (QuEChERS method). The quantification was carried out by liquid chromatography-tandem mass spectrometry with electrospray ionization source (LC-ESI-MS/MS). After the optimization of the extraction parameters, the method was validated by evaluating, linearity, limits of detection and quantification, precision (repeatability) and accuracy (recovery). Validation was based on analysis at three fortification levels and showed satisfactory recoveries (77.03 to 115.08 %) and high precision (RSDs between 2.01 to 13.83%). Low limits of detection and quantification could be achieved for all the five analytes ranging from 0.0007 to 0.002 and 0.002 to 0.008 μg/g, respectiv...