Persistence, dissipation, and risk assessment of a combination formulation of trifloxystrobin and tebuconazole fungicides in/on tomato.

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

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.

Development and Validation of an HPLC Method for Determination of Thiamethoxam and Its Metabolites in Cotton Leaves and Soil.

An easy and simple analytical method was standardized and validated for the estimation of residues of thiamethoxam and its metabolites in cotton. The samples were extracted with acetonitrile, water, and methanol; diluted with brine solution; partitioned into dichloromethane and ethyl acetate; dried over anhydrous sodium sulfate; and cleaned up by glass column chromatography. Final clear extracts were concentrated under vacuum and reconstituted into HPLC grade acetonitrile, and residues were estimated using an HPLC instrument equipped with a C18 column and photodiode array detector system. Acetonitrile-1% formic acid in HPLC grade water (30 + 70) was used as mobile phase at 0.2 mL/min. Consistent recoveries ranging from 82 to 97% for thiamethoxam and its metabolites were observed when samples were spiked at 0.05-1.0 mg/kg levels. The LOQ of the method was determined to be 0.05 mg/kg. The analytical method was validated in terms of the selectivity, linearity, precision, and accuracy of the detection system.

Effect of dehydrogenase, phosphatase and urease activity in cotton soil after applying thiamethoxam as seed treatment.

Soil enzymes are indicators of microbial activities in soil and are often considered as an indicator of soil health and fertility. They are very sensitive to the agricultural practices, pH of the soil, nutrients, inhibitors and weather conditions. To understand the effect of an insecticide, thiamethoxam, on different soil enzyme activities, the experiments were conducted at cotton experimental fields of Punjab Agricultural University, Ludhiana. The results here were presented to understand the impact of thiamethoxam on soil enzyme activities. Thiamethoxam was applied as seed treatment to control the pest. Soil from three localities, i.e. soil in which seed was treated with recommended dose at 2.1 g a.i. kg(-1), soil in which seed was treated with four times recommended dose at 8.4 g a.i. kg(-1) and from the control field, were tested for different enzyme activities. Phosphatase and dehydrogenase activities were high in control soil in comparison to control soil while no effect of this insecticide on urease activity. Thiamethoxam had inhibitory effects on dehydrogenase and phosphatase activities. Therefore, it can be attributed that agricultural practices, weather conditions and use of thiamethoxam might be responsible for the different level of enzyme activities in soil.

Enhancement of attributes of cereals by germination and fermentation: a review.

The nutritional quality of cereals and the sensorial properties of their products are sometimes inferior as compared to other sources of food which is due to the lower protein content and starch availability, the presence of determined antinutrients (phytic acid, tannins, and polyphenols) and the coarse nature of the grains. To ameliorate the nutritional qualities of cereals, they are processed in a number of ways. This review summarizes the enhancement in the nutritional value as well as the functional characteristics of cereals due to germination and fermentation treatment. The protein concentration increases and the amino acid profile is balanced by germination and fermentation. The antinutritional factors are reduced increasing the mineral availability from the cereals. Germination enhances the quality of nutrients and bioactive compounds of cereals thereby increasing the content in proteins, amino acids, sugars, and vitamins. The functional properties of cereals is enhanced due to generation of biofunctional substances, increase in protein solubility, in vitro protein digestibility and lowering of glycemic index.

Persistence and risk assessment of emamectin benzoate residues on okra fruits and soil.

Emamectin benzoate, a synthetic derivative of abamectin, is found effective against fruit borer and jassid in okra crops. The present studies were carried out to study the dissipation pattern of emamectin benzoate on okra and to suggest a suitable waiting period for the safety of consumers. Following three applications of emamectin benzoate (Proclaim 5 SG) at 68.1 and 136.2 g a.i. ha-1, the average initial deposits of emamectin benzoate were observed to be 0.22 and 0.42mg kg-1, respectively. These residues dissipated below the limit of quantification (LOQ) of 0.05 mg kg-1 after 5 days at both the dosages. Soil samples collected after 15 days did not reveal the presence of emamectin benzoate at LOQ of 0.05 mg kg-1. Acceptable daily intake (ADI) of emamectin benzoate is 0.0005 mg kg-1 body weight day-1, which means an adult of 55 kg weight can safely tolerate an intake of 27.50 microg emamectin benzoate. Assuming an average consumption of 80 g okra fruit and multiplying it by average and maximum residues observed on 0 day at recommended dosage, the intake of emamectin benzoate comes out to be about 20 Itg and these values are quite safe in comparison to its ADI. These studies, therefore, suggest that the use of emamectin benzoate at the minimum effective dosages do not seem to pose any hazards to the consumers if a waiting period of 1 day is observed.

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.

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.

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).

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.

Persistence of trifloxystrobin and tebuconazole on grape leaves, grape berries and soil.

Following four foliar applications of Nativo 75 WG (trifloxystrobin 25% + tebuconazole 50%) on grapes @ 175 and 350 g/ha, resulting in active applications of trifloxystrobin @ 43.75 and 87.5 g a.i./ha and that of tebuconazole @ 87.5 and 175 g a.i./ha, the average initial deposits of trifloxystrobin were observed to be 7.76 and 15.53 mg/kg, respectively, at single and double the application rates. These residue levels dissipated to >85% after 10 days of its application at both the dosages. Similarly, the average initial deposits of tebuconazole were observed to be 13.84 and 26.55 mg/kg at single and double the application rate, respectively. These residue levels dissipated to >90% after 10 days of application at both the dosages. The half-life (t(1/2)) periods of trifloxystrobin on grape leaves were observed to be 2.92 and 3.48 days at single and double application rates, respectively, whereas these values were 2.68 and 3.96 days for tebuconazole. Ripe grape berries and soil samples collected at harvest which happened to be 34 days after the last application, did not show the presence of residues of trifloxystrobin and tebuconazole at their determination limit of 0.01 and 0.02 mg/kg, respectively.

Dissipation kinetics of spinosad on cauliflower (Brassica oleracea var. botrytis. L.) under subtropical conditions of Punjab, India.

Residues of spinosad were estimated in cauliflower curds using high performance liquid chromatography (HPLC) and confirmed by high performance thin layer chromatography (HPTLC). Following three application of spinosad (Success 2.5 SC) at 15 and 30 g a.i. ha−1, the average initial deposits of spinosad were observed to be 0.57 and 1.34 mg kg−1, respectively. These residues dissipated below the limit of quantification (LOQ) of 0.02 mg kg−1 after 10 days at both the dosages. The half-life values (T 1/2) of spinosad were worked out to be 1.20 and 1.58 days, respectively, at recommended and double the recommended dosages. Thus, a waiting period of 6 days is suggested for the safe consumption of spinosad treated cauliflower.

Persistence of acephate and cypermethrin on cotton leaves, cottonseed, lint and soil.

Following foliar applications of combination formulation (cypermethrin 5% + acephate 45% DF) at 850 and 1,700 g ha(-1), resulting in active application of acephate at 382.5 and 765 g a.i. ha(-1) whereas active application of cypermethrin at 42.5 and 85 g a.i. ha(-1), the average initial deposits of acephate on cotton leaves were found to be 13.45 and 27.73 mg kg(-1), at single and double the doses of application, respectively. Residues of acephate declined below detectable level of 0.02 mg kg(-1) after 15 days of applications at application rates with t ((1/2)) values of 1.56 and 0.68 days, respectively. Similarly, the average initial deposits of cypermethrin were found to be 22.31 and 32.45 mg kg(-1), respectively. Cypermethrin residues reached below its detectable level of 0.02 mg kg(-1) after 21 days of its application at both the dosages of application. The half-life values for cypermethrin were observed to be 0.71 and 0.69 days, corresponding to single and double the dose of application, respectively. Interestingly, none of the samples of cottonseed, lint and soil showed presence of acephate or cypermethrin at the detection limit of 0.02 mg kg(-1) at first pick of the harvest time of the crop.

Persistence of imidacloprid on grape leaves, grape berries and soil.

Residues of imidacloprid were estimated in grape leaves, grape berries and soil following four applications of Confidor 200SL at 400 and 800 mL ha(-1) using 1,000 L water. The average initial deposits of imidacloprid on grape leaves were found to be 10.01 and 16.97 mg kg(-1) at single and double dosages, respectively. These residues of imidacloprid dissipated to be the extract of 98.8% and 97.0%, respectively, at single and double dosages in 15 days, with half-life period of 2.35 and 2.97 days. Residues of imidacloprid in grape berries at harvest time were observed to below determination limit of 0.05 mg kg(-1) at single dose and 0.06 mg kg(-1) at double dose. However, acceptable daily intake (ADI) of imidacloprid is 0.06 mg kg(-1) body weight day(-1), which means an adult of 60 kg and a child of 10 kg can safely tolerate intake of 3,600 and 600 microg imidacloprid, respectively, without any appreciable risk to their life. Assuming consumption of 200 g grape berries contaminated at 0.06 mg kg(-1), it will lead to an intake of only 12 microg of imidacloprid, which is quite safe for a child as well as for an adult. Hence, the use of imidacloprid on grape crop seems to be toxicologically acceptable.

Dissipation kinetics of propargite in brinjal fruits under subtropical conditions of Punjab, India.

Residues of propargite were estimated in brinjal fruits by High Performance Liquid Chromatography (HPLC) following single application of Omite 57 EC @ 570 and 1140 g a.i./ha. The average initial deposits of propargite were observed to be 0.51 and 0.92 mg/kg, respectively, which were below its maximum residue limit (MRL) of 2 mg/kg. The residue levels of propargite dissipated below limit of quantification (LOQ) of 0.02 mg/kg after 10 days at both the dosages. The half-life values (T(1/2)) of propargite were worked out to be 3.07 and 3.54 days, respectively, at recommended and double the recommended dosages. A waiting period of one day has been suggested for the safe consumption of brinjal fruits to avoid any health hazards.