Persistence evaluation of fluopyram + tebuconazole residues on mango and pomegranate and their risk assessment.

The persistence of combination formulation of fluopyram 200 + tebuconazole 200-400 SC was evaluated across different agro-climates in India for the management of fungal diseases in two commercially important fruit crops, mango and pomegranate. The residues were extracted using quick easy cheap effective rugged and safe (QuEChERS) method and quantification was done on liquid chromatography-tandem mass spectrometry (LC-MS/MS). The fungicide degradation followed 1st-order kinetics and the half-lives were 2.9-6.4 days for mango, and 3.5-7.4 days for pomegranate for both the fungicides. On the basis of Organisation for Economic Co-operation and Development (OECD) maximum residue limit (MRL) calculation, 1.0 mg kg-1 MRL was obtained for fluopyram while for tebuconazole, it was 0.5 mg kg-1 on mango, at the pre-harvest interval (PHI) of 5 days. For pomegranate, the respective MRLs were 1.0 mg kg-1 and 0.7 mg kg-1 at PHI of 7 days. The dietary risk assessment study indicated that % acceptable daily intake (% ADI) and % acute reference dose (% ARfD) were much lower than 100; thus, the application of fluopyram and tebuconazole on mango and pomegranate is unlikely to present public health concern.

Distribution of fluopyram and tebuconazole in pomegranate tissues and their risk assessment.

Residue distribution of fluopyram and tebuconazole was assessed in pomegranate whole fruit, aril, outer peel (pericarp), inner peel (mesocarp) and leaves. The method LOQ of fluopyram and tebuconazole were 0.01 and 0.02 mg kg-1, respectively. Both fungicides remained in fruit peel and residues in edible aril were < LOQ. In fruit peel major portion of the fungicides remained on pericarp with minimal movement to mesocarp. In mesocarp fluopyram was 5.7-14.2%; tebuconazole, 7.5-14.4% of the residues in pericarp. Terminal residues of fluopyram and tebuconazole in pomegranate whole fruit were 0.037-0.094 and 0.036-0.096 mg kg-1. Half-life of fluopyram in pomegranate fruit and leaves were 7.3-9.1 and 15 days; tebuconazole, 8-10.3 and 11.2-12.6 days, respectively. Pre-harvest intervals for treatment of combination formulation of fluopyram and tebuconazole, were 47-59 days in fruits, 158-173 in leaves. Dietary risk assessment demonstrated that consumption of peel and leaves may pose risk to human health, whereas fruit consumption was considered safe.

Dissipation kinetics and risk assessment of iprovalicarb + propineb fungicide in tomato under different agroclimates.

Multi-location supervised field trials in India were conducted with a combination pesticide formulation (iprovalicarb 5.5% + propineb 61.25%, 66.75% WP) in tomato to study dissipation behavior at single (iprovalicarb 137.5 g a.i. ha-1 + propineb 1531.25 g a.i. ha-1) and double (iprovalicarb 275 g a.i. ha-1 + propineb 3062.5 g a.i. ha-1) dose. The samples were processed using a modified QuEChERS method for iprovalicarb and acid hydrolysis followed by carbon disulfide estimation for propineb and confirmation of their respective residues by LC-MS/MS and GC-MS. Both the fungicides in tomato fruits obey first-order kinetics irrespective of location and doses. Half-life (t1/2) values at all the four locations ranged from 1.08 to 4.67 days for iprovalicarb and 3.36 to 11.41 days for propineb in tomato. The Food Safety and Standards Authority of India (FSSAI) has set MRL of 1 mg kg-1 for propineb, but no MRL is yet fixed for iprovalicarb. Using OECD MRL calculator, the calculated MRL for iprovalicarb and propineb was found to be 2 and 4 mg kg-1, respectively. The hazard quotient (HQ) < 1, theoretical maximum daily intake (TMDI) < acceptable daily intake (ADI), TMDI < maximum permissible intake (MPI), percent acute hazard index (% aHI) ≤ 1, and percent chronic hazard index (% cHI) < 1 for both the fungicides indicated that the combination formulation will not pose any dietary risk and thus considered safe for human health.

Behavior of acetamiprid, azoxystrobin, pyraclostrobin, and lambda-cyhalothrin in/on pomegranate tissues.

Pomegranate crop is affected by several insect pests and requires usage of a large number of pesticides, but the information on their behavior in pomegranate tissues is limited. A study was conducted to assess the behavior of acetamiprid, azoxystrobin, pyraclostrobin, and lambda-cyhalothrin in pomegranate fruits and leaves. The QuEChERS analytical method and LC-MS/MS and GC-MS were used for quantification of the analytes. The LOD (limit of detection) of acetamiprid, azoxystrobin, and pyraclostrobin was 0.0015 mg kg-1 and lambda-cyhalothrin was 0.003 mg kg-1. The respective LOQ (limit of quantification) was 0.005 and 0.01 mg kg-1. The dissipation of the analytes best fitted into first-order rate kinetics and the half-lives of the chemicals in pomegranate fruits were 9.2-13 days and in the leaves were 13.5-17 days. In the pomegranate aril, the residue levels of acetamiprid, lambda-cyhalothrin, and pyraclostrobin were always < LOQ of these chemicals. Azoxystrobin was detected in pomegranate aril, and its residue was highest at 0.04 mg kg-1 on the 10th day and reached < LOQ by the 25th day. The pre-harvest interval (PHI) required for acetamiprid, azoxystrobin, pyraclostrobin, and lambda-cyhalothrin at standard-dose treatment was 50, 58, 44, and 40 days, respectively. From double-dose treatment, the PHIs were 70, 75, 58, and 54 days, respectively. The pesticides used in this study were more persistent in the pomegranate leaves compared to the fruits. The outcome of this study can be incorporated into production of pomegranate fruits safe for consumption and to meet the domestic and export quality control requirements.

Dissipation kinetics and consumer risk assessment of novaluron + lambda-cyhalothrin co-formulation in cabbage.

Cabbage, one of the most popular vegetables in the world is infested by several insect-pests and diseases. Novaluron, a chitin synthesis inhibitor and lambda-cyhalothrin, a synthetic pyrethroid group insecticide are used to manage insect-pests on cabbage. The dissipation kinetics and risk assessment of combination formulation (novaluron 9.45% + lambda-cyhalothrin 1.9%) with different modes of action has not yet been investigated in cabbage. Multi-location supervised field trials were therefore, conducted in different agro-climatic regions of India for safety evaluation of the combination product. The co-formulation at the recommended (novaluron 750 g a.i. ha-1 + lambda-cyhalothrin 750 g a.i. ha-1) and double the recommended (novaluron 1500 g a.i. ha-1 + lambda-cyhalothrin 1500 g a.i. ha-1) dose was sprayed on the cabbage crop. The samples were extracted and cleaned up using a modified QuEChERS method, and the residues analyzed by GC-ECD and GC-MS. The half-life (t1/2) varied between 1.77 and 2.51 and 2.00-3.38 days for novaluron and 1.36-2.24 and 1.69-3.82 days for lambda-cyhalothrin in cabbage at respective doses. The Food Safety and Standards Authority of India (FSSAI) has set the MRL of 0.7 mg kg-1 for novaluron at PHI of 5 days, and no MRL is set for lambda-cyhalothrin in cabbage. On the basis of OECD MRL calculator, the MRLs of 0.6 and 1.5 mg kg-1 for novaluron and lambda-cyhalothrin, respectively were calculated at the respective doses at PHI of 3 days. Hazard quotient (HQ) <1, theoretical maximum daily intake (TMDI) < acceptable daily intake (ADI) and < maximum permissible intake (MPI), percent acute hazard index (% aHI) <1, and percent chronic hazard index (% cHI) <1 for both novaluron and lambda-cyhalothrin suggested that the combination formulation is safe and will not pose any dietary risk to the consumers. The study will be helpful to conduct risk assessment of other pesticides/combination pesticides on food crops on which their MRLs have not yet been fixed.

Persistence and dissipation study of azoxystrobin, buprofezin, dinocap and hexaconazole on mango (Mangifera indica L.).

Azoxystrobin, buprofezin, dinocap and hexaconazole are widely used in crop protection of mango from flowering to harvest. Residue assessment of these chemicals on mango fruits was done following treatments at the recommended and double doses as per good agricultural practices (GAP). Mango fruit and soil sample preparation was done by QuEChERS, and analysis was done using LC-MS/MS (liquid chromatography mass spectrometry). Using these techniques, the limit of detection (LOD) determined was 1.5 µg kg-1 and limit of quantification (LOQ) was 0.005 mg kg-1 for all analytes. The residue levels on mango initially were 0.265 and 0.55 mg kg-1 for azoxystrobin, 0.63 and 0.974 mg kg-1 for buprofezin, 0.635 and 0.98 mg kg-1 for dinocap and 0.203 and 0.35 mg kg-1 for hexaconazole from standard and double dose treatments, respectively. The dissipation rate of the pesticides on mango fruits was about the same except for azoxystrobin, which dissipated slowly compared with others. The half-life of degradation (DT50) of azoxystrobin was 10.4-12.1 days; buprofezin, 5.8-8.5 days; dinocap, 5.4-6.2 days; and hexaconazole, 4.4-6.1 days. The pre-harvest interval (PHI) based on European Union (EU) MRL (maximum residue limit) requirements were 1 day for azoxystrobin, 15 and 26 days for buprofezin, 27 and 34 days for dinocap, and 19 and 30 days for hexaconazole. The results of this study can be used to produce mango fruits safe for consumption and to meet the regulatory requirements for export of mango fruits from India.

Dissipation of neonicotinoid insecticides imidacloprid, indoxacarb and thiamethoxam on pomegranate (Punica granatum L.).

Neonicotinoid insecticides such as imidacloprid, indoxacarb and thiamethoxam are widely used for control of a large number of insect pests of pomegranate crop. Their residue levels were evaluated on pomegranate fruits over 2 years during the same cropping season. The QuEChERS analytical method in conjunction with LC-MS/MS was validated to analyse the insecticides on pomegranate fruits with peel (whole fruit), without peel (aril) and in the field soil. The method performance was satisfactory with the limit of quantification (LOQ) of 0.005 mg/kg which was below the maximum residue limits (MRLs) in pomegranate for the 3 compounds. A first order reaction kinetics was observed for the three insecticides with the half -life of degradation of 8-11.1 days for imidacloprid; 7.4-8.4 days for indoxacarb and 9.8-14.2 days for thiamethoxam. Though the insecticides are systemic in nature, the residues in the edible pomegranate aril were always < LOQ. The maximum residue levels of imidacloprid on pomegranate was less than its MRL of 1 mg/kg, so the pre-harvest interval (PHI) required was 1 day only. For indoxacarb, 31-42 days PHI was needed for the residues to reduce to its MRL of 0.02 mg/kg. The PHI of thiamethoxam was 46-77 days, the time required for its residues to reduce to its MRL of 0.01 mg/kg. Higher rainfall possibly facilitated faster dissipation of imidacloprid residues from pomegranate whereas indoxacarb and thiamethoxam remained unaffected. The results of the study can be utilized to incorporate these three chemicals in the plant protection program of pomegranate and fixation of MRL in India.

Uptake and distribution of fluopyram and tebuconazole residues in tomato and bell pepper plant tissues.

The present study describes the uptake and distribution of fungicides, fluopyram, and tebuconazole in tomato and bell pepper plant tissues from the soil drench application of their combination product fluopyram17.7% + tebuconazole 17.7%. For extraction and cleanup of fluopyram, its metabolite fluopyram benzamide, and tebuconazole samples, the QuEChERS method was used in conjunction with LC-MS/MS. The limit of detection (LOD) and limit of quantification (LOQ) of the method determined were 1.5 µg kg-1 and 0.005 mg kg-1, respectively, and recoveries of all analytes from sample matrices remained within the acceptable range of 70-120%. Rapid uptake of the fungicides by tomato and bell pepper plants was observed from the first day onwards. In the tomato plant, the major part of the fungicides accumulated in the roots, whereas in bell pepper plant, it accumulated both in the roots and in the leaves. Accumulation of fluopyram and tebuconazole residues was lowest in tomato and bell pepper fruits which were much below their respective maximum residue limits (MRLs). The highest residue concentration of fluopyram and tebuconazole in tomato fruits was 0.060 and 0.009 mg kg-1; the corresponding values in bell pepper fruits were 0.080 and 0.013 mg kg-1. In field soil, fluopyram residues were 3.18-3.570 mg kg-1 initially which dissipated at the half-life of 36 days. Tebuconazole concentration was 1.57-1.892 mg kg-1 initially, and it dissipated at the half-life of 44.5-49.5 days. The major metabolite of fluopyram, fluopyram benzamide, was detected in plant tissues as well as in soil, and remained within 12% of the parent compound. The results of the study indicated that fluopyram and tebuconazole are less likely of entry into food chain through intake of tomato and bell pepper fruits if these crops are grown on soil contaminated with these fungicides.

Persistence, dissipation and consumer risk assessment of a combination formulation of flubendiamide and deltamethrin on cucumber.

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.

Dissipation of spiromesifen and spiromesifen-enol on tomato fruit, tomato leaf, and soil under field and controlled environmental conditions.

Dissipation of spiromesifen and its metabolite, spiromesifen-enol, on tomato fruit, tomato leaf, and soil was studied in the open field and controlled environmental conditions. Sample preparation was carried out by QuEChERS method and analysis using LC-MS/MS. Method validation for analysis of the compounds was carried out as per "single laboratory method validation guidelines." Method validation studies gave satisfactory recoveries for spiromesifen and spiromesifen-enol (71.59-105.3%) with relative standard deviation (RSD) < 20%. LOD and LOQ of the method were 0.0015 µg mL-1 and 0.005 mg kg-1, respectively. Spiromesifen residues on tomato fruits were 0.855 and 1.545 mg kg-1 in open field and 0.976 and 1.670 mg kg-1 under polyhouse condition, from treatments at the standard and double doses of 125 and 250 g a.i. ha-1, respectively. On tomato leaves, the residues were 5.64 and 8.226 mg kg-1 in open field and 6.874 and 10.187 mg kg-1 in the polyhouse. In soil, the residues were 0.532 and 1.032 mg kg-1 and 0.486 and 0.925 mg kg-1 under open field and polyhouse conditions, respectively. The half-life of degradation of spiromesifen on tomato fruit was 6-6.5 days in the open field and 8.1-9.3 days in the polyhouse. On tomato leaves, it was 7-7.6 and 17.6-18.4 days and in soil 5.6-7.4 and 8.4-9.5 days, respectively. Metabolite, spiromesifen-enol, was not detected in any of the sample throughout the study period. Photodegradation could be the major route for dissipation of spiromesifen in the tomato leaves, whereas in the fruits, it may be the combination of photodegradation and dilution due to fruit growth. The results of the study can be utilized for application of spiromesifen in plant protection of tomato crop under protected environmental conditions.

Residue level and dissipation of carbendazim in/on pomegranate fruits and soil.

Carbendazim is widely used on pomegranate for control of a large number of fungal diseases. Its residue levels in/on pomegranate fruits and soil were evaluated under field conditions. The quick, easy, cheap, effective, rugged, and safe (QuEChERS) method in conjunction with liquid-chromatography mass spectrometry was used for analysis of carbendazim. Recovery of carbendazim was within 78.92-96.28 % and relative standard deviation within 3.8-10.9 % (n = 6). Carbendazim residues on pomegranate fruits dissipated at the half lives of 17.3 and 22.8 days from treatments at 500 and 1000 g active ingredient (a.i.) ha(-1), respectively. Its residues in pomegranate aril were highest on the tenth day and reduced thereafter. The residue level of carbendazim on pomegranate whole fruits from standard dose treatment was less than the EU maximum residue limit (MRL) of 0.1 mg kg(-1) at harvest. The carbendazim residues were

Residue level and dissipation pattern of spiromesifen in cabbage and soil from 2-year field study.

Spiromesifen is a new class of insecticide used for the control of whiteflies and mites which have developed resistance to the more commonly used neonicotinoids. Dissipation pattern of spiromesifen on cabbage was evaluated over 2 years by conducting supervised field studies as per good agricultural practices. Cabbage and soil samples were extracted and purified using modified QuEChERS method and analyzed through gas chromatography (GC). Confirmatory studies were carried out by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The recoveries of spiromesifen from cabbage and soil were between 85.44 and 103.37% with the relative standard deviation (RSD) between 3.2 and 9.4% (n = 6). The limit of detection (LOD) and limit of quantification (LOQ) were 0.003 µg mL(-1) and 0.01 mg kg(-1), respectively. The measurement uncertainties (MUs) were within 9.9-14.9%. Initial residues of spiromesifen on cabbage were 0.640 and 1.549 mg kg(-1) during 2013 and 0.723 and 1.438 mg kg(-1) during 2014 from treatments at standard and double doses of 125 and 250 g active ingredient (a.i.) ha(-1), respectively. Spiromesifen residue dissipation followed first-order rate kinetics, and it degraded within the half-lives of 2.9 and 3.9 days during 2013 and 3.2 and 4.5 days during 2014. The residue levels reached below the maximum residue limit (MRL; 0.02 mg kg(-1)) within 15-17 days at the standard dose and 24-27 days at the double dose. The field soil analyzed at harvest (30 days) was free from spiromesifen residues. Metabolite spiromesifen-enol was not detected in any sample which was confirmed through LC-MS/MS analysis.

Dynamics of difenoconazole and propiconazole residues on pomegranate over 2 years under field conditions.

Residue dynamics of difenoconazole and propiconazole on pomegranate was studied after application at the recommended and double doses of 125 and 250 g active ingredient (a.i.) ha(-1) during August-October 2012. The study was repeated during the same period in 2013. QuEChERS method, in conjunction with gas chromatography (GC), was used for analysis of the fungicides after carrying out the method validation. The recoveries of the fungicides from pomegranate and soil were between 80.3 and 96.2 %; the limit of detection (LOD) and limit of quantification (LOQ) were 0.016 and 0.05 mg kg(-1), respectively. The uncertainties of measurement were between 9.7 and 16.3 %. The initial residue deposits of difenoconazole were 0.875 and 1.205 mg kg(-1) from treatment at the recommended dose and 1.54 and 1.672 mg kg(-1) from treatment at the double dose from the first- and second-year studies. Propiconazole residues were 0.663 and 0.864 mg kg(-1) from recommended dose treatments and 1.474 and 2.045 mg kg(-1) from double dose treatments from the first- and second-year studies. The half-lives of degradation of difenoconazole were 6.4-8.4 days and propiconazole 7.9-8.5 days over the 2 years. Residues of difenoconazole and propiconazole remained on the pomegranate fruit surface and did not move to the edible part (aril). The pre-harvest intervals (PHIs), the time required for the residues to reduce below their respective EU maximum residue limits (MRLs), were 25.4 and 30.8 days for difenoconazole and 33.3 and 43.8 days for propiconazole from treatments at the recommended and double doses, respectively. Keeping in view consumer safety, the longer PHI from the two studies has been selected.

Dissipation pattern of flubendiamide residues on capsicum fruit (Capsicum annuum L.) under field and controlled environmental conditions.

This investigation was undertaken to compare the dissipation pattern of flubendiamide in capsicum fruits under poly-house and open field after giving spray applications at the recommended and double doses of 48 g a.i. ha(-1) and 96 g a.i. ha(-1). Extraction and purification of capsicum fruit samples were carried out by the QuEChERS method. Residues of flubendiamide and its metabolite, des-iodo flubendiamide, were analyzed by high-performance liquid chromatography-photodiode array, and confirmed by liquid chromatography-mass spectrometry/mass spectrometry. Limit of quantification of the method was 0.05 mg kg(-1), and recovery of the insecticides was in the range of 89.6-104.3%, with relative standard deviation being 4.5-11.5%. The measurement uncertainty of the analytical method was in the range of 10.7-15.7%. Initial residue deposits of flubendiamide on capsicum fruits grown under poly-house conditions were (0.977 and 1.834 mg kg(-1)) higher than that grown in the field (0.665 and 1.545 mg kg(-1)). Flubendiamide residues persisted for 15 days in field-grown and for 25 days in poly-house-grown capsicum fruits. The residues were degraded with the half-lives of 4.3-4.7 and 5.6-6.6 days in field and poly-house respectively. Des-iodo flubendiamide was not detected in capsicum fruits or soil. The residues of flubendiamide degraded to below the maximum residue limit notified by Codex Alimentarius Commission (FAO/WHO) after 1 and 6 days in open field, and 3 and 10 days in poly-house. The results of the study indicated that flubendiamide applied to capsicum under controlled environmental conditions required longer pre-harvest interval to allow its residues to dissipate to the safe level.

Comparison of the residue persistence of trifloxystrobin (25%) + tebuconazole (50%) on gherkin and soil at two locations.

Residue study of trifloxystrobin and tebuconazole on gherkin was carried out at two locations (Bangalore and Gouribiddunur, India) after applications at the standard and double doses of 75 + 150 and of 150 + 300 g ha(-1) of the formulated product, trifloxystrobin (25%) + tebuconazole (50%) (Nativo 75 WG). The fungicides were determined by gas chromatography (GC) and confirmed by gas chromatography-mass spectrometry (GC-MS). Extraction and purification of the samples were carried out by Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method after validating the analytical parameters. Initial residues of trifloxystrobin on gherkin fruits were 0.335 and 0.65 mg kg(-1) at Bangalore, and 0.34 and 0.615 mg kg(-1) at Gouribiddunur. Tebuconazole residues were 0.842 and 1.682 mg kg(-1) at Bangalore, and 0.71 and 1.34 mg kg(-1) at Gouribiddunur. Residue dissipation of the fungicides followed first-order rate kinetics. Trifloxystrobin residues dissipated at the half-life of 2.9-3.7 days, and tebuconazole at 3.2 days. At the standard dose treatment, trifloxystrobin residues dissipated to below the maximum residue limit (MRL) of 0.2 mg kg(-1) (European Union) within 3 days at both the locations. Residues of the metabolite CGA 321113 was less than the limit of quantification (LOQ; 0.05 mg kg(-1)) on all sampling days. Tebuconazole residues dissipated to below its MRL (0.05 mg kg(-1)) within 14 and 11 days, at Bangalore and Gouribiddunur, respectively. From the two trials, it was concluded that the required pre-harvest interval (PHI) for the combination formulation was 14 days. Application of Nativo 75 WG should be given before flowering to allow the residues to dissipate below the MRLs at harvest.

Residue evaluation of imidacloprid, spirotetramat, and spirotetramat-enol in/on grapes (Vitis vinifera L.) and soil.

A combination of imidacloprid and spirotetramat effectively controls sucking pests on grapevines. Residues of these insecticides on grapes were evaluated after treatment with spirotetramat 12% + imidacloprid 12% (240 SC) three times at 90 and 180 g a.i. ha(-1). The samples were extracted and purified by QuEChERS method and analyzed by high-performance liquid chromatography with a photodiode array detector (imidacloprid) and gas chromatography mass spectrometry (spirotetramat and its metabolite spirotetramat-enol). Satisfactory results were obtained with ranges of 80.6-98.6% for the recovery, 3.1-10% for the relative standard deviation range, and 9.8-15.6% for the uncertainty. The limits of detection and quantification were 0.015 µg mL(-1) and 0.05 mg kg(-1), respectively. Initial residue concentrations of imidacloprid after the 90 and 180 g a.i. ha(-1) treatments were 0.912 (half-life 11 days) and 1.681 mg kg(-1) (half-life 12.4 days), respectively. For spirotetramat + spirotetramat-enol, the residue concentrations were 1.337 (half-life 5.6 days) and 2.0 mg kg(-1) (half-life 7.6 days) for the 90 and 180 g a.i. ha(-1) treatments, respectively. Spirotetramat degraded faster than spirotetramat-enol. After treatment at 90 g a.i. ha(-1), the initial residues of both insecticides were within European Union maximum residue limits and a 1-day pre-harvest interval (PHI) was adequate for safe consumption of grapes. After treatment at 180 g a.i. ha(-1), the required PHI was 7 day. Therefore, a PHI of 7 day should be used after treatment with imidacloprid and spirotetramat.

Dissipation pattern and risk assessment of flubendiamide on chili at different agro-climatic conditions in India.

Dissipation pattern and risk assessment of flubendiamide and its metabolite (desiodo flubendiamide) on chili were studied at four different agro-climatic locations of India at the standard and double dose at 60 and 120 g a.i. ha(-1) at 10 days interval. Quantification of residues was done on a high-performance liquid chromatograph (HPLC) with a photo diode array detector. The limit of quantification (LOQ) of this method was found to be 0.01 mg kg(-1) while limit of detection (LOD) being 0.003 mg kg(-1). Residues of flubendiamide were found to be below the determination limit in 15 days at both the dosages in all locations. Half-life of flubendiamide when applied at 60 and 120 g a.i. ha(-1) ranged from 0.85 to 1.80 and from 0.95 to 2.79 days, respectively. On the basis of data generated under the All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 1 day has been recommended and the flubendiamide 480 SC has been registered for use on chili in India by the Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on chili has been fixed by the Food Safety Standard Authority of India, Ministry of Health and Family Welfare, Government of India, as 0.02 µg g(-1) after its risk assessment.

Residue levels and dissipation behaviors for trifloxystrobin and tebuconazole in mango fruit and soil.

An evaluation of residue levels of trifloxystrobin and tebuconazole was carried out on mango fruits after treatments with the combined formulation, trifloxystrobin (25 % w/w) and tebuconazole (50 % w/w), at standard and double doses of 250 + 500 and 500 + 1000 g a.i. ha(-1), respectively. Extraction and purification of the mango fruit samples were carried out by the QuEChERS method after validating the analytical parameters. Determination of the fungicides was carried out by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The limits of detection (LOD) and limits of quantification (LOQ) for both fungicides were 0.015 µg mL(-1) and 0.05 mg kg(-1), respectively. The residue levels of trifloxystrobin for standard and double-dose treatments were 0.492 and 0.901 mg kg(-1) and for tebuconazole were 0.535 and 1.124 mg kg(-1), respectively. A faster dissipation of tebuconazole in mango fruit was observed compared with that for tebuconazole. Dissipation of trifloxystrobin and tebuconazole in mango followed first-order kinetics, and the half-lives were 9 and 6 days, respectively. The preharvest intervals (PHI), the time taken for the combined residues of trifloxystrobin and tebuconazole to dissipate to their permissible levels (maximum residue limits), were 14 and 20 days for standard and double doses, respectively. At harvest, mature mango fruit and soil were free from fungicide residues.

Persistence and dissipation kinetics of trifloxystrobin and tebuconazole in onion and soil.

The persistence and dissipation kinetics of trifloxystrobin and tebuconazole on onion were studied after application of their combination formulation at a standard and double dose of 75 + 150 and 150 + 300 g a.i. ha(-1). The fungicides were extracted with acetone, cleaned-up using activated charcoal (trifloxystrobin) and neutral alumina (tebuconazole). Analysis was carried out by gas chromatograph (GC) and confirmed by gas chromatograph mass spectrometry (GC-MS). The recovery was above 80% and limit of quantification (LOQ) 0.05 mg kg(-1) for both fungicides. Initial residue deposits of trifloxystrobin were 0.68 and 1.01 mg kg(-1) and tebuconazole 0.673 and 1.95 mg kg(-1) from standard and double dose treatments, respectively. Dissipation of the fungicides followed first-order kinetics and the half life of degradation was 6-6.6 days. Matured onion bulb (and field soil) harvested after 30 days was free from fungicide residues. These findings suggest recommended safe pre-harvest interval (PHI) of 14 and 25 days for spring onion consumption after treatment of Nativo 75 WG at the standard and double doses, respectively. Matured onion bulbs at harvest were free from fungicide residues.

Persistence and dissipation of quinalphos in/on cauliflower and soil under the semi arid climatic conditions of Karnataka, India.

Persistence and dissipation of quinalphos residues in/on cauliflower was studied after giving spray applications at 2 concentrations, i.e. recommended dose of 500 g a.i. ha(-1) and double the recommended dose of 1,000 g a.i. ha(-1). Residue analysis of cauliflower curds was carried out after the third spray over a period of 15 days. Initial residues of quinalphos on cauliflower from the two treatments were 1.19 and 1.842 mg kg(-1). The residues persisted up to 15 days from both the treatments. The residues of quinalphos dissipated from both treatments with the half-life of 4.8 and 5.3 days. Based on the persistence study and maximum residue limit value of 0.05 mg kg(-1) the safe pre-harvest interval was worked out as 17 and 22 days from treatment at the recommended and double the recommended dose, respectively. Analysis of soil samples was carried out on the 15th day of sampling and residues were found to be 0.013 and 0.044 mg kg(-1).