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.

Safety evaluation of flubendiamide and its metabolites on cabbage and persistence in soil in different agroclimatic zones of India.

Supervised field trials following good agricultural practices were conducted at the research farms of four agricultural universities located at four different agroclimatic zones of India to evaluate the persistence and dissipation of flubendiamide and its metabolite, des-iodo flubendiamide, on cabbage. Two spray applications of flubendiamide 480 SC of standard and double dose at the rate of 24 and 48 g a.i. ha(-1) were given to the crop at a 15-day interval, and the residues of flubendiamide 2 h after spray were found in the range of 0.107-0.33 and 0.20-0.49 mg kg(-1) at respective doses. Residue of des-iodo flubendiamide was not detected in any cabbage sample during study period. No residues were found in the soil samples collected from all treated fields after 15 days of application. On the basis of data generated under All India Network Project on Pesticide Residues, a preharvest interval (PHI) of 10 days has been recommended, and the flubendiamide 480 SC has been registered for its use on cabbage by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India. The maximum residue limit (MRL) of flubendiamide on cabbage has been fixed by the Ministry of Health and Family Welfare, Government of India, under Food Safety Standard Authority of India as 0.05 µg/g after its risk assessment.

Risk assessment of ß-cyfluthrin and imidacloprid in chickpea pods and leaves.

Dissipation of ß-cyfluthrin and imidacloprid in chickpea pods and leaves was measured following three applications of Solomon 300 OD (ß-cyfluthrin 9 percent +imidacloprid 21 percent) at 200 and 400mLha(-1). Residues of ß-cyfluthrin on chickpea pods and leaves were found to be below its limit of quantification (LOQ) of 0.01mgkg(-1) after 7 days at both the dosages. Similarly, imidacloprid residues were found to be below its LOQ of 0.01mgkg(-1) at 10 days. Half-life periods on chickpea pods and leaves for ß-cyfluthrin were found to be 1.06 and 0.58 days, whereas for imidacloprid these values were observed to be 2.07 and 1.75 days at recommended dose. As the theoretical maximum residue contributions on chickpea pods and leaves are found to be less than the maximum permissible intake values even on 0 day, therefore consumer health risks are minimal at both the dosages on chickpea.

Estimation of quizalofop ethyl residues in black gram (Vigna mungo L.) by gas liquid chromatography.

Quizalofop ethyl, a phenoxy propionate herbicide is used for post emergence control of annual and perennial grass weeds in broad-leaved crops in India. The experiments were designed to study the harvest time residues of quizalofop ethyl in black gram for two seasons. At harvest time, the residues of quizalofop ethyl on black gram seed, foliage and soil were found to be below the determination limit of 0.01 mg kg(-1) following a single application of the herbicide at 50 and 100 g a.i. ha(-1) for both the periods. Application of the herbicide is quite safe from a consumer and environmental point of view.

Degradation dynamics of emamectin benzoate on cabbage under subtropical conditions of Punjab, India.

Emamectin benzoate (Proclaim 5 SG) was applied to cabbage at 8.5 and 17 g a.i. ha⁻¹, during the head initiation stage. A high performance liquid chromatography (HPLC) analytical method, for the determination of emamectin benzoate in cabbage, was developed. Average recoveries of emamectin benzoate ranged from 92 % to 96 % at different fortification levels (0.05, 0.25 and 0.50 mg kg⁻¹). The initial deposits, 0.11 and 0.21 mg kg⁻¹ of emamectin benzoate at 8.5 and 17 g a.i. ha⁻¹, dissipated below the determination limit of 0.05 mg kg⁻¹ in 3 and 5 days, respectively.

Persistence of thiacloprid residues on brinjal (Solanum melongena L.).

Thiacloprid, a neonicotinoid insecticide with novel mode of action, is found to be effective against several lepidopteran as well as hemipteran pests. The present studies were carried out to observe the persistence pattern of thiacloprid on brinjal and to suggest suitable waiting period for the safety of consumers. Persistence of thiacloprid in brinjal was studied following three applications of thiacloprid (Alanto 240 SC) at 180 and 360 g a.i. ha(-1) at 7 days interval. Residues of thiacloprid in brinjal were estimated by high-performance liquid chromatography and were confirmed by liquid chromatography-mass spectrometry. The average initial deposits of thiacloprid were observed to be 0.48 and 1.05 mg kg(-1) on the brinjal fruit following third application of thiacloprid at recommended and double the recommended dosages, respectively. Half-life periods for thiacloprid were found to be 0.47 and 0.50 days at single and double the application rates, respectively. Residues of thiacloprid declined below its limit of quantification of 0.05 mg kg(-1) after 3 and 5 days, respectively, at recommended and double the recommended application rates. Therefore, the use of thiacloprid does not seem to pose any risk hazard and a waiting period of 1 day is suggested for safe consumption of brinjal fruits.

Estimation of chlorpyriphos and cypermethrin residues in chilli (Capsicum annuum L.) by gas-liquid chromatography.

Dissipation of chlorpyriphos and cypermethrin in chilli was studied following three applications of a combination formulation of Nurelle-D 505 (chlorpyriphos 50% + cypermethrin 5%) at 1 and 2 L ha(-1) at an interval of 15 days. Residues of chlorpyriphos and cypermethrin in chilli were estimated by gas-liquid chromatography and confirmed by gas chromatography-mass spectrometry. Half-life periods for chlorpyriphos were found to be 4.43 and 2.01 days, whereas for cypermethrin these values were observed to be 2.51 and 2.64 days at single and double the application rates, respectively. Residues of chlorpyriphos dissipated to more than 80% after 10 days at both the dosages. However, residues of cypermethrin dissipated to the extent of more than 70% in 7 days. Soil samples collected after 15 days of the last application did not show the presence of chlorpyriphos and cypermethrin at their respective determination limit of 0.01 mg kg(-1). The use of chlorpyriphos and cypermethrin mixture at the recommended dosage does not seem to pose any hazards to the consumers, and a waiting period of 1 day is suggested to reduce the risk before consumption of green chilli.

Residual behavior of quizalofop ethyl on onion (Allium cepa L.).

Quizalofop ethyl, a phenoxy propionate herbicide, is used for postemergence control of annual and perennial grass weeds in broad-leaved crops in India. The experiments were designed to study the dissipation kinetics of quizalofop ethyl on onion for two seasons. A simple, rapid, and sensitive method for estimation of quizalofop ethyl residues in onion and soil was developed and validated. The recoveries of quizalofop ethyl residues from onion and soil at different spiking level range from 84.81 to 92.68 %. The limit of quantification of this method was found to be 0.01 µg g(-1). The risk assessment through consumption of the onion in comparison to its acceptable daily intake which is an important parameter for the safety of the consumer was also evaluated. Standardized methodology supported by recovery studies was adopted to estimate residues of quizalofop ethyl on onion and soil. The average initial deposits of quizalofop ethyl on onion were observed to be 0.25 and 0.33 mg kg(-1), following single application of the herbicide at 50 g active ingredient (a.i.) ha(-1) during 2009 and 2010, respectively. The half-life values (T (1/2)) of quizalofop ethyl on onion crop were worked out to be 0.85 and 0.79 days, respectively, during 2009 and 2010. At harvest time, the residues of quizalofop ethyl on onion and soil were found to be below the determination limit of 0.01 mg kg(-1) following single application of the herbicide at 50 and 100 g a.i. ha(-1) for both the periods.

Dissipation kinetics of trifloxystrobin and tebuconazole on wheat leaves and their harvest time residues in wheat grains and soil.

Following single application of Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) on wheat crop @ 300 and 600 g ha(-1), resulting in active application of trifloxystrobin @ 75.0 and 150.0 g a.i. ha(-1) and tebuconazole @ 150 and 300 g a.i. ha(-1), the average initial deposits of trifloxystrobin on wheat leaves were 5.54 and 8.30 mg kg(-1), and that of tebuconazole were 14.66 and 27.94 mg kg(-1), respectively. Half-life values for trifloxystrobin were observed to be 2.80 and 2.51 days whereas those for tebuconazole were found to be 2.46 and 1.85 days at recommended and double the recommended dosages, respectively. The residues of trifloxystrobin and tebuconazole dissipated to the extent of >89% at both the dosages after 7 days. Wheat grain samples at harvest having pre harvest interval of 140 days did not show the presence of trifloxystrobin and tebuconazole at their determination limit of 0.01 mg kg(-1).

Persistence and dissipation kinetics of deltamethrin on chili in different agro-climatic zones of India.

Multi-location supervised field trials were conducted at four different agro climatic locations in India to evaluate the dissipation pattern of deltamethrin on chili. Deltamethrin 10 EC was applied on chili @17.5 and 35 g a.i. ha(-1), samples of green chili were drawn at different time intervals and that of red chili and soil at harvest time and quantified by gas liquid chromatography equipped with electron capture detector. The identity of residues were confirmed by Gas Chromatograph-Mass Spectrophotometer in selective ion monitoring mode in mass range 181, 253 m/z. Limit of quantification of the method was found to be 0.01 mg kg(-1). Half-life of deltamethrin at application rate of 17.5 g a.i. ha(-1) varied from 0.36 to 1.99 days and at double the application rate was found to range from 0.38 to 2.06 days. Residues of deltamethrin were found below its determination limit of 0.01 mg kg(-1) in red chili and soil. On the basis of the data generated, Deltamethrin 10 EC has been registered for use on chili in India and its Maximum Residue Limit has been fixed as 0.05 µg/g.

Persistence of fipronil and its risk assessment on cabbage, Brassica oleracea var. capitata L.

Persistence of fipronil in cabbage was studied following three applications of Jump 80 WG at 75 and 150 g a.i. ha(-1) at 7 day interval. The average initial deposits of total fipronil (fipronil and its metabolites) were 1.226 and 2.704 mg kg(-1) on the heads following 3rd application of fipronil at single and double the dosages, respectively. Desulfinyl was found to be the main metabolite followed by sulfone and sulfide. Metabolite amide was not detected in cabbage samples. Half-life periods for fipronil were found to be 3.43 and 3.21 day at single and double the application rates, respectively. Risk assessment of fipronil to the consumers was calculated on the basis of per capita 80 g consumption of cabbage and comparing it to its ADI for an adult of 55 kg which was found to be less than its ADI on 10th day at both the dosages.

Estimation of indoxacarb residues by QuEChERS technique and its degradation pattern in cabbage.

Indoxacarb residues were estimated by employing standardized QuEChERS technique in cabbage following three applications of Avant(R) 14.8 EC @ 52.2 and 104.4 g a.i. ha(-1). The average recoveries of indoxacarb on cabbage for fortification levels of 0.01, 0.05 and 0.1 mg kg(-1) were observed to be 83.93, 89.86 and 95.40%, respectively, with relative standard deviation of 1.21, 1.53 and 2.23. The method was also validated with respect to parameters of linearity, precision and limit of quantification (LOQ). The LOQ for cabbage was found to be 0.01 mg kg(-1). The average initial deposits of indoxacarb on cabbage were observed to be 0.18 and 0.39 mg kg(-1), respectively, at single and double the application rate. These indoxacarb residues dissipated below its LOQ of 0.01 mg kg(-1)after 7 and 10 days, respectively, at single and double dosages. Half-life of indoxacarb was observed to be 2.88 and 1.92 days, respectively, at recommended and double the recommended dosages.

Dissipation kinetics of trifloxystrobin and tebuconazole on chili and soil.

Dissipation of trifloxystrobin and tebuconazole were studied following two applications of a combination formulation of Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) @ 250 and 500 g ha(-1) at 10 days interval. Samples of chili were collected at 0, 1, 3, 5, 7, 10 and 15 days after the last application. Red chili and soil samples were collected after 20 days of last application. Half-life period for trifloxystrobin were found to be 1.81 and 1.58 days and for tebuconazole these values were observed to be 1.37 and 1.41 days, respectively, at single and double the application rates. Trifloxystrobin residues dissipated below its limit of quantification (LOQ) of 0.01 mg kg(-1) after 5 and 7 days, respectively, at single and double the application dosages whereas tebuconazole residues took 7 and 10 days, respectively. Red chili & soil samples collected after 20 days did not reveal the presence of trifloxystrobin and tebuconazole at their determination limit of 0.01 mg kg(-1).

Assessment of flubendiamide residues in pigeon pea in different agro-climatic zones of India.

Supervised field trials were conducted at the research farms of four agricultural universities located at different agro-climatic zones of India to find out the harvest time residues of flubendiamide and its des-iodo metabolite on pigeon pea (Cajanus cajan) during the year 2006-2007. Two spray applications of flubendiamide 20 WDG at 50 g (T(1)) and 100 g (T(2)) a.i./ha were given to the crop at 15-days interval. The foliage samples at different time intervals were drawn at only one location, however, the harvest time samples of pigeon pea grain, shell, and straw were drawn at all the four locations. The residues were estimated by HPLC coupled with UV-VIS variable detector. No residues of flubendiamide and its des-iodo metabolite were found at harvest of the crop at or above the LOQ level of 0.05 µg/g. On the basis of the data generated, a pre-harvest interval (PHI) of 28 days has been recommended and the flubendiamide 20 WDG has been registered for use on pigeon pea by Central Insecticide Board and Registration Committee, Ministry of Agriculture, Government of India and the MRL has been fixed by Ministry of Health and Family Welfare, Government of India under Prevention of Food and Adulteration as 0.05 µg/g on pigeon pea grains.

Estimation of ß-cyfluthrin and imidacloprid in okra fruits and soil by chromatography techniques.

Dissipation of ß-cyfluthrin and imidacloprid in okra was studied following three applications of a combination formulation of Solomon 300 OD (ß-cyfluthrin 9 % + imidacloprid 21 %) @ 60 and 120 g a.i. ha(-1) at 7 days interval. Residues of ß-cyfluthrin and imidacloprid in okra were estimated by gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC), respectively. Residues of ß-cyfluthrin were confirmed by gas chromatograph-mass spectrometry (GC-MS) and that of imidacloprid by high performance thin layer chromatography (HPTLC). Half-life periods for ß-cyfluthrin were found to be 0.91 and 0.68 days whereas for imidacloprid these values were observed to be 0.85 and 0.96 days at single and double the application rates, respectively. Residues of ß-cyfluthrin dissipated below its limit of quantification (LOQ) of 0.01 mg kg(-1) after 3 and 5 days at single and double the application dosage, respectively. Similarly, residues of imidacloprid took 5 and 7 days to reach LOQ of 0.01 mg kg(-1), at single and double dosages respectively. Soil samples collected after 15 days of the last application did not show the presence of ß-cyfluthrin and imidacloprid at their detection limit of 0.01 mg kg(-1).

Residual behaviour and risk assessment of flubendiamide on chickpea (Cicer arietinum L.).

The study was undertaken to determine the disappearance trends of flubendiamide residues on chickpea under field conditions and thereby, ensure consumer safety. Average initial deposits of flubendiamide on chickpea pods were found to be 0.68 and 1.17 mg kg(-1), respectively, following three applications of flubendiamide 480SC @ 48 and 96 g a.i. ha(-1) at 7d intervals. Half-life of flubendiamide on chickpea pods was observed to be 1.39 and 1.44 d, respectively, at single and double dosages whereas with respect to chickpea leaves, these values were found to be 0.77 and 0.86 d. Desiodo flubendiamide was not detected at 0.05 mg kg(-1) level on chickpea samples collected at different intervals. Theoretical maximum residue contribution (TMRC) for flubendiamide was calculated and found to be well below the maximum permissible intake (MPI) on chickpea pods and leaves at 0-day (1 h after spraying) for the both dosages. Thus, the application of flubendiamide at the recommended dose on chickpea presents no human health risks and is safe to the consumers.

Persistence of propargite on okra under subtropical conditions at Ludhiana, Punjab, India.

Residues of propargite were estimated in okra fruits by high performance liquid chromatography following single application of Omite 57 EC @570 and 1,140 g a.i./ha. Residues of propargite were confirmed by high performance thin layer chromatography. The average initial deposits of propargite were observed to be 1.36 and 3.32 mg/kg, respectively, which were below its maximum residue limit of 2 mg/kg. The residue levels of propargite dissipated below its limit of quantification of 0.02 mg/kg after 7 days at single dose and after 10 days at double dose. The half-life values (T 1(/)2) of propargite were worked out to be 0.79 and 0.73 days, respectively, at recommended and double the recommended dosages.

Dissipation kinetics of beta-cyfluthrin and imidacloprid in brinjal and soil under subtropical conditions of Punjab, India.

Dissipation of beta-cyfluthrin and imidacloprid was studied following three applications of a combination formulation of Solomon 300 OD (beta-cyfluthrin 9% + imidacloprid 21%) @ 60 and 120 g a.i. ha(-1) at 7 days interval. Samples of brinjal were collected at 0, 1, 3, 5, 7, 10 and 15 days after the last application and residues of beta-cyfluthrin and imidacloprid were estimated on gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC), respectively. Half-life periods for beta-cyfluthrin were found to be 1.74 and 1.39 days and for imidacloprid these values were observed to be 2.31 and 2.18 days, respectively, at single and double the application rate. beta-Cyfluthrin residues dissipated below the limit of quantification (LOQ) of 0.01 mg kg(-1) after 5 and 7 days, respectively, at single and double the application dosages whereas imidacloprid residues took 10 days for both the dosages. Soil samples collected after 15 days after the last application did not show the presence of beta-cyfluthrin and imidacloprid at their detection limit of 0.01 mg kg(-1).

Dissipation kinetics of flubendiamide on chili and soil.

Average initial deposits of flubendiamide on chili were found to be 1.06 and 2.00 mg kg(-1), respectively, following two applications of flubendiamide 480SC at 60 and 120 g a.i. ha(-1) at 10 days interval. More than 80% of flubendiamide residues dissipated just after 3 days of the last application at both the dosages. Residues of flubendiamide dissipated below detectable level of 0.01 mg kg(-1) in 7 and 10 days at single and double dosages, respectively. Half-life (t(1/2)) of flubendiamide on chili was observed to be 0.96 and 0.91 days, respectively, at single and double dosages. Desiodo flubendiamide was not detected at 0.01 mg kg(-1) level in chili samples collected at different time intervals. Red chili and soil samples collected after 20 days did not reveal the presence of flubendiamide or its metabolite desiodo flubendiamide.