Determination of 73 multi-class pesticides in okra (Abelmoschus esculentus L.) fruits using LC-MS/MS and GC-MS/MS and estimation of analytical uncertainty of measurement.

This study developed a method to simultaneously determine 73 multi-class pesticides in okra fruit using LC-MS/MS and GC-MS/MS. The sample was extracted with acetonitrile and subsequent clean-up through dispersive-SPE method. The quantification level of the technique was 0.01 µg g-1 and compliance to the MRLs fixed by the regulatory bodies like EU and FSSAI. The recovery at 10, 50, and 100 µg kg-1 spiked levels; intra and inter-day precision at 50 µg kg-1 were found within 70-120% with RSD less than 15% with LC-MS/MS and GC-MS/MS. Measurement uncertainty was in the range of 1.81 to 12.91 µg kg-1 estimated at 50 µg kg-1. The matrix effects were slightly higher for LC than GC-compatible pesticides. Risk assessment for pesticides detected in the field and market samples found no hazardous to the consumers except profenofos. The proposed method is highly sensitive, reproducible for the complex matrix like okra, and meets the regulatory standards.

Determination of chlorantraniliprole 18.5% SC in the paddy ecosystem and its risk assessment.

Chlorantraniliprole belongsto theanthranilic diamide group is widely used against broad range of lepidopteron pests in a variety of vegetable and rice pests includingyellow rice stem borer and leaf folder. Supervised field trials were conducted duringRabi (2018-2019) and Kharif (2019) to evaluate the dissipation pattern and risk assessment of chlorantraniliprole 18.5% SC in paddy ecosystem following foliar application at 30 and 60 g a.i. ha-1 in two different cropping seasons.Modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) technique was used for the extraction of CAP residues with acetonitrile and determined by LC-MS/MS (ESI +).The limit of quantification (LOQ) was 0.01 µg g-1 for paddy leaf, straw, husk, and brown rice, respectively and 0.005 µg g-1 for soil. The average recoveries obtained were 84.30-88.92% from paddy leaf, 94.25-97.81% from straw, 90.21-93.38% from husk, 93.57-96.40% from brown rice and 89.93-91.14% from soil. The residues in paddy leaf dissipated within 35-40 days with a half-life of 4.33-5.07 days in Rabi and 3.92-4.86 days in Kharif at 30 and 60 g a.i. ha-1, respectively. The residues in soil dissipated within 15-21 days with a half-life of 14.44-15.75 days in Rabi and 13.33-14.44 days in Kharif at respective doses. At harvest chlorantraniliprole residues were not detected in straw, husk, and brown rice. The dietary risk of paddy leaf (green fodder) for cattle was found safe for consumption as the hazard index is less than one. Soil ecological risk assessment was found to be less than one (RQ < 0.1) for earthworms (Eisenia foetida) and arthropods (Aphidiusrhopalosiphi). The presentmethod could be useful inthe analysis ofchlorantraniliproleresidues in different cereals and vegetable crop ecosystems and application at recommended dose is safe for the final produce at harvest.

Characterization of phyto-components with antimicrobial traits in supercritical carbon dioxide and soxhlet Prosopis juliflora leaves extract using GC-MS.

This study aimed to screen the bioactive compounds from Prosopis juliflora leaf supercritical fluid extract and to assess its antimicrobial properties. Supercritical carbon dioxide and Soxhlet methods were used for extraction. The extract was subjected to Gas Chromatography-Mass Spectrometer (GC-MS) and Fourier Transform Infrared for the characterization of the phyto-components. When compared to soxhlet extraction, more components (35) were eluted by supercritical fluid extraction (SFE), according to GC-MS screening. Rhizoctonia bataticola, Alternaria alternata, and Colletotrichum gloeosporioides were all successfully inhibited by P. juliflora leaf SFE extract, which demonstrated strong antifungal properties with mycelium percent inhibition of 94.07%, 93.15%, and 92.43%, respectively, compared to extract from Soxhlet, which registered 55.31%, 75.63% and 45.13% mycelium inhibition respectively. Also, SFE P. juliflora extracts registered higher zone of inhibition 13.90 mm, 14.47 mm and 14.53 mm against all three test food-borne bacterial pathogens viz Escherichia coli, Salmonella enterica and Staphylococcus aureus respectively. Results obtained from GC-MS screening revealed that SFE is more efficient than soxhlet extraction in recovering the phyto-components. P. juliflora may provide antimicrobial agents, a novel natural inhibitory metabolite.

A new species and new record of the genus Pexicopia (Lepidoptera: Gelechiidae) feeding on Abutilon indicum from India.

A new species, Pexicopia tungabhadrai sp. nov. (Lepidoptera: Gelechiidae), feeding on Abutilon indicum is described from Karnataka, India. Also, this is the first report of the genus Pexicopia Common, 1958 from India. Images of adult moths, male and female genitalia and immature stages are provided.

Simultaneous determination of pesticide residues in pomegranate whole fruit and arils using LC-MS/MS.

An analytical method in pomegranate whole fruits and arils was developed in LC-MS/MS and validated as per SANTE/12682/2019. Samples were extracted following acetonitrile-based modified QuEChERS protocol. The method was linear and the coefficient of determination ranged between 0.998 and 0.999. Through this method, all the pesticides were detected and quantified at 10 µg kg-1. The accuracy test at 10, 50, and 100 µg kg-1 spiking level recorded recovery between 70 and 120% and RSD less than 15% in both matrices. No significant matrix effect was observed for most pesticides. Intra (RSDr) and inter-day (RSDwr) precision estimated at 50 µg kg-1 found acceptable RSD in both matrices. Measurement uncertainty at 50 µg kg-1 was in the range of 4.02 to 16.12 µg kg-1. Quantifying pesticides in pomegranate whole fruits, peel, and arils using the proposed method is highly suitable and reproducible for 74 pesticides in a short run time of 25.00 min.

Simultaneous determination, dissipation and decontamination of fungicides applied on cabbage using LC-MS/MS.

A method for simultaneous determination of carbendazim and tebuconazole residues in cabbage was developed and validated in LC-MS/MS. Samples were extracted and purified following the modified QuEChERS procedure, which enabled the elution of carbendazim and tebuconazole at 0.96 and 5.31 min, respectively. LOD and LOQ were 0.0005 and 0.0015 mg kg-1, respectively. Mean recovery was in the range of 78.94 to 104.89% for carbendazim and 76.07 to 98.62% for tebuconazole. The field samples recorded residues of 0.274 and 0.481 mg kg-1; and 0.194 and 0.392 mg kg-1 at single and double dose for carbendazim and tebuconazole, respectively. Half-life values were 2.17 and 2.99 for carbendazim and 2.74 and 2.81 for tebuconazole at single and double dose, respectively. Decontamination with saltwater wash followed by cooking and lemon water wash found superior in the removal of residues more than 90%.

Evidence for facultative migratory flight behavior in Helicoverpa armigera (Noctuidae: Lepidoptera) in India.

Despite its deleterious impact on farming and agriculture, the physiology and energetics of insect migration is poorly understood due to our inability to track their individual movements in the field. Many insects, e.g. monarch butterflies, Danaus plexippus (L.), are facultative migrants. Hence, it is important to establish whether specific insect populations in particular areas migrate. The polyphagous insect, Helicoverpa armigera (Hübner), is especially interesting in this regard due to its impact on a variety of crops. Here, we used a laboratory-based flight mill assay to show that Helicoverpa armigera populations clearly demonstrate facultative migration in South India. Based on various flight parameters, we categorized male and female moths as long, medium or short distance fliers. A significant proportion of moths exhibited long-distance flight behavior covering more than 10 km in a single night, averaging about 8 flight hours constituting 61% flight time in the test period. The maximum and average flight speeds of these long fliers were greater than in the other categories. Flight activity across sexes also varied; male moths exhibited better performance than female moths. Wing morphometric parameters including forewing length, wing loading, and wing aspect ratio were key in influencing long-distance flight. Whereas forewing length positively correlated with flight distance and duration, wing loading was negatively correlated.

Simultaneous determination of 79 pesticides in pigeonpea grains using GC-MS/MS and LC-MS/MS.

Pigeonpea grains are important sources of vegetarian proteins. It is the paramount importance to check the pesticide residues due to their frequent use during production. The LC-MS/MS and GC-MS/MS analytical method was developed and validated for the simultaneous determination of 79 pesticide residues in pigeonpea. The LOD and LOQ of the analytical method were in the range of 0.53 to 3.97 and 1.60 to 10.05 µg kg-1, respectively, with a correlation coefficient of more than 0.997. Average recoveries were in the range of 80 to 118.8%, with the RSD of less than 15%. Measurement uncertainty (Ux) for pesticides was in the range of 3.42 to 12.76 µg kg-1 evaluated at 50 µg kg-1. The method was applied to analyze the sample collected from the farmer's field. This method could be useful for routine analysis of selected pesticide residue for monitoring purposes.

Genome Mining and Expression Analysis of Carboxylesterase and Glutathione S-Transferase Genes Involved in Insecticide Resistance in Eggplant Shoot and Fruit Borer, Leucinodes orbonalis (Lepidoptera: Crambidae).

The shoot and fruit borer, Leucinodes orbonalis (Lepidoptera: Crambidae) is the major cause of low productivity in eggplant and insecticides being the mainstay of management of L. orbonalis. However, field control failures are widespread due to the evolution of insecticide resistance. Taking advantage of the whole genome sequence information, the present study investigated the level of insecticide resistance and the expression pattern of individual carboxylesterase (CE) and glutathione S-transferases (GSTs) genes in various field collected populations of L. orbonalis. Dose-mortality bioassays revealed a very high level of resistance development against fenvalerate (48.2-160-fold), phosalone (94-534.6-fold), emamectin benzoate (7.2-55-fold), thiodicarb (9.64-22.7-fold), flubendiamide (187.4-303.0-fold), and chlorantraniliprole (1.6-8.6-fold) in field populations as compared to laboratory-reared susceptible iso-female colony (Lo-S). Over-production of detoxification enzymes viz., CE and GST were evident upon enzyme assays. Mining of the draft genome of L. orbonalis yielded large number of genes potentially belonging to the CE and GST gene families with known history of insecticide resistance in other insects. Subsequent RT-qPCR studies on relative contribution of individual genes revealed over-expression of numerous GSTs and few CEs in field populations, indicating their possible involvement of metabolic enzymes in insecticide resistance. The genomic information will facilitate the development of novel resistance management strategies against this pest.

Mitochondria COI-based genetic diversity of the cotton leafhopper Amrasca biguttula biguttula (Ishida) populations from India.

Amrasca biguttula biguttula (Ishida), the cotton leafhopper, is a polyphagous insect pest of Asia and Southeast Asian countries. We sequenced a mitochondrial COI gene fragment from 67 individuals of cotton leafhopper collected from 7 major cotton growing states of North, Central, and South India. Genetic divergence analysis of leaf hopper population across India confirmed the presence of single species. Thirty haplotypes, in total, were determined across different regions of India. While population from North India was dominated by single haplotype, the south and central Indian populations show dispersion of different haplotypes across the region. The neutrality test rejection for the north Indian population also suggests population expansion. The genetic differentiation and gene flow analysis together confirmed the phylogeographic structure of the A. biguttula biguttula Ishida as isolated by distance.