Development of an analytical method for analysis of flubendiamide, des-iodo flubendiamide and study of their residue persistence in tomato and soil

Flubendiamide is a new insecticide that has been found to give excellent control of lepidopterous pests of tomato. This study has been undertaken to develop an improved method for analysis of flubendiamide and its metabolite des-iodo flubendiamide and determine residue retention in tomato and soil. The analytical method developed involved extraction of flubendiamide and its metabolite des-iodo flubendiamide with acetonitrile, liquid-liquid partitioning into hexane-ethyl acetate mixture (6:4, v v?1) and cleanup with activated neutral alumina. Finally the residues were dissolved in gradient high pressure liquid chromatography (HPLC) grade acetonitrile for analysis by HPLC. The mobile phase, acetonitrile-water at 60:40 (v v?1) proportion and the wavelength of 235 nm gave maximum peak resolution. Using the above method and HPLC parameters described, nearly 100 % recovery of both insecticides were obtained. There was no matrix interference and the limit of quantification (LOQ) of the method was 0.01 mg kg?1. Initial residue deposits of flubendiamide on field-treated tomato from treatments @ 48 and 96 g active ingredient hectare?1 were 0.83 and 1.68 mg kg?1, respectively. The residues of flubendiamide dissipated at the half-life of 3.9 and 4.4 days from treatments @ 48 and 96 g a.i. ha?1, respectively and persisted for 15 days from both the treatments. Des-iodo flubendiamide was not detected in tomato fruits at any time during the study period. Residues of flubendiamide and des-iodo flubendiamide in soil from treatment @ 48 and 96 g a.i. ha?1 were below detectable level (BDL, < 0.01 mg kg?1) after 20 days. Flubendiamide completely dissipated from tomato within 20 days when the 480 SC formulation was applied at doses recommended for protection against lepidopterous pests.     

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.     

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 7 d 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.     

Dissipation and Leaching of 14C-Monocrotophos in Soil Columns under Subtropical Climate

Dissipation and leaching behavior of ¹⁴C-monocrotophos was studied for 365 days under field conditions using PVC cylinders. The first set (24 cylinders) was spiked with 1.0 μCi ¹⁴C-labeled monocrotophos along with 1.06 mg unlabeled monocrotophos to give a concentration of 2 mg kg ^?1 in the soil up to 15 cm depth. The second set (24 cylinders) received ¹⁴C-labeled monocrotophos along with other non-labeled insecticides viz., dimethoate @ 300 g a.i ha^?1, deltamethrin @ 12.5 g a.i ha^?1, endosulfan @ 750 g a.i ha^?1, cypermethrin @ 60 g a.i ha^?1, and triazophos @ 600 g a.i ha^?1 at an interval of 15 days each as recommended for the cotton crop. ¹⁴C-monocrotophos dissipated faster, up to 45% in first 90 days in columns treated with only monocrotophos compared to 25% in columns that received monocrotophos along with other insecticides. However, both the columns showed similar residues 180 days onward. After 180 days of treatment, 46% radiolabeled residues were observed, which reduced up to 39.6% after 365 days. Leaching of ¹⁴C-monocrotophos to 15–30 cm soil layer was observed in both the experimental setups. In the 15–30 cm soil layer of both soil columns, up to 0.19 mg ¹⁴C-monocrotophos kg^?1d. wt. soil was detected after 270 days.     

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

Dissipation of β-cyfluthrin and imidacloprid in okra was studied following three applications of a combination formulation of Solomon 300 OD (β-cyfluthrin 9 % + imidacloprid 21 %) @ 60 and 120 g a.i. ha^?1 at 7 days interval. Residues of β-cyfluthrin and imidacloprid in okra were estimated by gas liquid chromatography (GLC) and high performance liquid chromatography (HPLC), respectively. Residues of β-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 β-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 β-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 β-cyfluthrin and imidacloprid at their detection limit of 0.01 mg kg^?1.     

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.     

Application of indoxacarb for managing shoot and fruit borer of eggplant (Solanum melongena L.) and its decontamination

Indoxacarb was applied at 75 and 150 g a.i. ha^{? 1} for two years to an eggplant (Solanum melongena L.) crop grown in the field plots in order to evaluate its efficacy for management of the lepidopteron pest, shoot and fruit borer. The residues of the insecticide were quantified by high-pressure liquid chromatography (HPLC). The mean initial deposits of indoxacarb on eggplant fruits were found to be 2.60–2.634 mg kg^{? 1} and 3.64–3.68 mg kg^{? 1} from the two rates of applications, respectively. They declined with time and reached to non-detectable (< 0.02 mg kg^{? 1}) after 15–20 d. Residues dissipated with a half-life of 3.0–3.8 d from both first and second-year application. A 3 d waiting period for harvest of fruits after insecticide application and processing resulted in the residue levels that were below the Codex maximum residue limit (MRL) of 0.5 mg kg^{? 1} thereby achieving a maximum safety and minimum risk to consumers. The best combination of chemicals for decontamination of indoxacarb was found to be by washing with a mixture of alkali and potassium permanganate (KMnO₄) thereby resulting in the removal of 67.5% and 59.2 % residues for 5 and 10 μ g g^{? 1} spiking doses, respectively. Major products formed on reaction of indoxacarb with alkali were identified by electron spray ionization chromatography/mass spectrometry (ESI/MS). The per cent reduction on the weight and number basis of treated eggplant plots were compared to those observed in control plots to demonstrate the effectiveness of indoxacarb treatment on shoot and fruit borer population.     

Concentration and dissipation of chlorantraniliprole and thiamethoxam residues in maize straw,maize, and soil

To study the dissipation rates and final residual levels of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil, two independent field trials were conducted during the 2014 cropping season in Beijing and Anhui Provinces of China. A 40% wettable powder (20% chlorantraniliprole?+?20% thiamethoxam) was sprayed onto maize straw and soil at an application rate of 118 g of active ingredient per hectare (g a.i.ha^?1). The residual concentrations were determined by ultra-high-performance liquid chromatography–tandem mass spectrometry. The chlorantraniliprole half-lives in maize straw and soil were 9.0–10.8 and 9.5–21.7 days, respectively. The thiamethoxam half-lives in maize straw and soil were 8.4–9.8 and 4.3–11.7 days, respectively. The final residues of chlorantraniliprole and thiamethoxam in maize straw, maize, and soil were measured after the pesticides had been sprayed two and three times with an interval of 7 days using 1 and 1.5 times the recommended rate (72 g a.i. ha^?1 and 108 g a.i. ha^?1, respectively). Representative maize straw, maize, and soil samples were collected after the last treatment at pre-harvest intervals of 7, 14, and 28 days. The chlorantraniliprole residue was below 0.01 mg kg^?1 in maize, between 0.01 and 0.31 mg kg^?1 in maize straw, and between 0.03 and 1.91 mg kg^?1 in soil. The thiamethoxam residue concentrations in maize, maize straw, and soil were <0.01, <0.01, and 0.01–0.03 mg kg^?1, respectively. The final pesticide residues on maize were lower than the maximum residue limit (MRL) of 0.02 mg kg^?1 after a 14-day pre-harvest interval. Therefore, a dosage of 72 g a.i. ha^?1 was recommended, as it can be considered safe to human beings and animals.     

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.     

Effect of the veterinary ionophore monensin on the structure and activity of a tropical soil bacterial community

Abstract

Monensin (MON) is a coccidiostat used as a growth promoter that can reach the environment through fertilization with manure from farm animals. To verify whether field-relevant concentrations of this drug negatively influence the structure and activity of tropical soil bacteria, plate counts, CO₂ efflux measurements, phospholipid fatty acids (PLFA) and community-level physiological profiling (CLPP) profiles were obtained for soil microcosms exposed to 1 or 10?mg kg^?1 of MON across 11?days. Although 53% (1?mg kg^?1) to 40% (10?mg kg^?1) of the MON concentrations added to the microcosms dissipated within 5?days, a subtle concentration-dependent decrease in the number of culturable bacteria (<1 log CFU g^?1), reduced (?20 to ?30%) or exacerbated (+25%) soil CO₂ effluxes, a marked shift of non-bacterial fatty acids, and altered respiration of amines (1.22-fold decrease) and polymers (1.70-fold increase) were noted in some of the treatments. These results suggest that MON quickly killed some microorganisms and that the surviving populations were selected and metabolically stimulated. Consequently, MON should be monitored in agronomic and environmental systems as part of One Health efforts.     

Effect of compost and manure amendments on zinc soil speciation, plant content, and translocation in an artificially contaminated soil

The addition of organic matter in soil can modify the bioavailability of heavy metals. A greenhouse pot experiment was carried out using an edible plant species Eruca vesicaria L. Cavalieri grown on an artificially contaminated soil with Zn (665 mg?kg^?1). In this study, the effect of compost at 20 t?ha^?1 (C20) and at 60 t?ha^?1 (C60), manure at 10 t?ha^?1 (M10) and at 30 t?ha^?1 (M30), and chemical fertilizers (NPK) on Zn fate in a soil–plant system was evaluated. At the end of the experiment, the main growth parameters and Zn content in plants were determined. In addition, Zn speciation in the soil was assessed using the original Community Bureau of Reference sequential extraction and diethylene triamine pentaacetic acid extraction. Zinc, though an essential element for plant growth, caused toxicity effects in plants grown on control and manure treatments, while in the compost treatments, plants showed no visual toxicity symptoms. The concentrations of Zn in roots were similar for all treatments, while significant differences were observed for shoots. In fact, in the compost treatments, plants showed the lowest Zn concentration in shoots. Zinc speciation seems not to be affected by the applied treatments. Indeed, Zn plant content and translocation to shoots seems to be affected. Compost amendments significantly reduced Zn content and translocation in comparison to other treatments.     

Deposition and Leaching of Tebuthiuron on Sugar Cane Straw Applied with and Without Alkyl Polyglycoside Adjuvant

Abstract

A laboratory experiment was carried out aiming to study the effects of an alkyl polyglycoside adjuvant (APG) on deposition and leaching of the herbicide tebuthiuron applied on sugar cane straw. Tebuthiuron, at concentration of 1200 mg L^?1, was applied separately and in tank mix with the APG adjuvant, at concentrations of 0.07 and 0.09% (wt v^?1), using a spraying volume of 204 L ha^?1. A precipitation equivalent to 20 mm of rain was simulated, 24 h after the applications, to evaluate the herbicide leaching. The quantification of tebuthiuron was carried out by the high performance liquid chromatography (HPLC). It was observed that the addition of APG adjuvant at 0.07% (wt v^?1) provided an increase of 11.5% in the deposition of tebuthiuron on straw, reduction of 50.4% in the drift of the herbicide and it did not affect significantly the leached amount (68.5%), when compared with the treatment where tebuthiuron was applied alone (70.8%). At the concentration of 0.09% (wt v^?1), the APG adjuvant caused an increase of 22.7% in the deposition; it reduced the drift of the herbicide by 99.9% and reduced the leached amount by 7.6% thereby increasing the retention of the herbicide by straw.     

Impact of Sublethal Doses of 2,4-D,Simulating Drift,on Tomato Yield

Abstract

Tomato is considered one of the most sensitive crops regarding 2,4-D drift. In many cases, such susceptibility has led to important restrictions in the use of 2,4-D based products. Field experiments were carried out for two consecutive years in tomato, by applying sublethal doses of 2,4-D (ranging from 0.42 to 13.44 g a.i. ha^?1) directly to plants, at different stages of growth, as a simulation of eventual drifts to the crop. The range of rates was based on the assumption of a 0.0625–2.0% drift level of a 1 L ha^?1 of the most common formulated herbicides. For this crop, the range of rates between 0.42 and 13.44 g a.i ha^?1 applied at the beginning of flowering caused a linear crop reduction. On the other hand, rates ≤13.44 g a.i. ha^?1 applied after full development of fourth truss stage or latter had no effect on crop yield or development. For tomato, tolerance to 2,4-D strongly increases with plant age.     

Phytoremediation for co-contaminated soils of chromium and benzo[a]pyrene using Zea mays L.

A greenhouse experiment was carried out to investigate the single effect of benzo[a]pyrene (B[a]P) or chromium (Cr) and the joint effect of Cr–B[a]P on the growth of Zea mays, its uptake and accumulation of Cr, and the dissipation of B[a]P over 60 days. Results showed that single or joint contamination of Cr and B[a]P did not affect the plant growth relative to control treatments. However, the occurrence of B[a]P had an enhancing effect on the accumulation and translocation of Cr. The accumulation of Cr in shoot of plant significantly increased by?≥?79 % in 50 mg kg^?1 Cr–B[a]P (1, 5, and 10 mg kg^?1) treatments and by?≥?86 % in 100 mg kg^?1 Cr–B[a]P (1, 5, and 10 mg kg^?1) treatments relative to control treatments. The presence of plants did not enhance the dissipation of B[a]P in lower (1and 5 mg kg^?1) B[a]P contaminated soils; however, over 60 days of planting Z. mays seemed to enhance the dissipation of B[a]P by over 60 % in 10 mg kg^?1 single contaminated soil and by 28 to 41 % in 10 mg kg^?1B[a]P co-contaminated soil. This suggests that Z. mays might be a useful plant for the remediation of Cr–B[a]P co-contaminated soil.     

Dissipation of pendimethalin in the soil of field pea (Pisum sativum L.) and detection of terminal residues in plants

Dissipation of pendimethalin in the soil of field peas (Pisum sativum L.) at 0 to 110 days, and terminal residues in green and mature pea were studied under field conditions. Pendimethalin was applied as pre-emergence herbicide at 750, to 185 g a.i. ha^?1 in winter, in field peas. Dissipation of pendimethalin in the soil at 0 to 110 days followed first-order kinetics showing a half-life of 19.83 days averaged over all doses. Low pendimethalin residues were found in mature pea grain (0.004, 0.003, <0.001 μg g^?1), and straw (0.007, 0.002, <0.001 μg g^?1) at 750, 350 and 185 g a.i. ha^?1 treatments, respectively. The study indicated that residues of pendimethalin in green and mature pea were within the prescribed MRL limits.     

Antibiotic uptake by plants from manure-amended soils

Antibiotics are extensively given to livestock to promote growth and reduce diseases. Therefore, animal manure often contains antibiotics. Once manure is applied to agricultural land to improve soil productivity, crops would be exposed to antibiotics which may persist in soils from a few to several hundred days. The objective of this study was to evaluate the uptake of gentamicin and streptomycin by carrot (Daucus carota), lettuce (Lactuca sativa) and radish (Rhaphanus sativus) from manure-amended soil. The treatments were 0, 0.5 and 1 mg of antibiotic kg^?1 of soil. Two pot experiments were carried out in the greenhouse. The first was conducted on the three crops and the second exclusively on radish. In radish, the increase in the concentrations of gentamicin was significant between the 0 and both of 0.5 and 1.0 mg kg^?1 treatments, but not significant between the 0.5 and 1.0 mg kg^?1. The average values were 35.5, 60.0 and 57.4 μg kg^?1 for the 0, 0.5 and 1 mg kg^?1 rates, respectively. However, the increase in streptomycin concentration in radish was not significant between the three treatments, and the average values were, 12.1, 15.2 and 17.4 μg kg^?1 for the 0, 0.5 and 1 mg kg^?1 rates, respectively. In carrot roots and lettuce leaves no significant increase in the concentrations of gentamicin or streptomycin was observed between the treatments. The three crops absorbed relatively higher amounts of gentamicin (small molecule) than streptomycin (large molecule). Generally the levels of antibiotics in plant tissue increased with increasing the antibiotic concentration in the manure (1 mg kg^?1 > 0.5 mg kg^?1).     

Soil Persistence of Triasulfuron Herbicide as Affected by Biotic and Abiotic Factors

Persistence of triasulfuron [3-(6-methoxy-4methyl-1,3,5-triazin-2-yl)-1-{2-(2-chloroethoxy)-phenylsulfonyl}-urea] in soil was studied under wheat crop and laboratory conditions. Field experiment was conducted in the farms of Agronomy Division, Indian Agricultural Research Institute (IARI), New Delhi. Randomized block design (RBD) was followed with four replicates and two rates of treatments along with control and weedy check. Triasulfuron was applied as post-emergent application to wheat crop at two rates of application viz., 15 g and 20 g a.i. ha^?1. Soil samples at 0 (3 h), 1, 3, 5, 7, 10, 15, 20, and 30-day intervals after application were drawn, extracted, cleaned up, and analyzed for herbicide residues by high performance liquid chromatography (HPLC) using C₁₈ column and methanol: water (8:2) as mobile phase at 242 nm wave length. Effect of microbial activity and soil pH was studied under laboratory conditions. Dissipation of triasulfuron followed a first-order-rate kinetics. Residues dissipated from field soil with half-life of 5.8 and 5.9 days at two rates of application. The study indicated biphasic degradation with faster rate initially (t _1/2 = 3.7 days), followed by a slower dissipation rate at the end (t _1/2 = 9.4 days). Similar trend was observed with non-sterile soil in laboratory with a longer half-life. Acidic pH and microbial activity contributed toward the degradation of triasulfuron in soil.     

Residue determination and dissipation of ioxynil octanoate in maize and soil

A simple and efficient residue analysis method for direct determination of ioxynil octanoate in maize and soil was developed and validated with High Performance Liquid Chromatography-Ultra Violet (HPLC-UV). The samples were extracted with mixtures of acetonitrile and deionized water followed by Solid Phase Extraction (SPE) to remove co-extractives prior to analysis by HPLC-UV. The recoveries of ioxynil octanoate extracted from maize and soil samples ranged from 86 %–104 % and 84 %–96 %, respectively, with relative standard deviation (RSD) less than 7.84% and sensitivity of 0.01 mg kg^?1. The method was applied to determine the residue of ioxynil octanoate in maize and soil samples from experimental field. Data had shown that the dissipation rate in soil was described as pseudo-first-order kinetics and the half-life (t_1/2) was less than 1.78 days. No ioxynil octanoate residue (<0.01 mg kg^?1) was detected in maize at harvest time withholding period of 60 days after treatments of the pesticide. Direct confirmation of the analytes in field trial samples was realized by Liquid Chromatography-Mass Spectrometry (LC-MS).     

Determination of Fungicide Kresoxim-Methyl Residues in Cucumber and Soil by Capillary Gas Chromatography with Nitrogen-Phosphorus Detection

The method of residue analysis of kresoxim-methyl and its dissipation rate in cucumber and soil in a greenhouse were studied. Residues of kresoxim-methyl were extracted from cucumber and soil matrices with acetone, purified by liquid-liquid extraction and Florisil cartridges, and then determined by GC with NP-detector. The limit of detection was estimated to be 9× 10^?12 g, and the minimum determination concentration of kresoxim-methyl in the samples was 0.005 mg kg^?1. The average recoveries ranged from 89.4 to 100.2% with a coefficient variation between 2.4 and 8.9%. Dissipation study showed that the half-lives of kresoxim-methyl in cucumber were approximately 6.5 days at both the recommended and double the recommended dosage. Half-lives for both the treatments were approximately 8 days in soil. The present study revealed that the residues in cucumber were below the MRL (0.05 mg kg^?1, fixed by EU) after 7 days for both treatments.     

Supplementation of nitrocompounds in broiler diets: Effects on bird performance,ammonia volatilization and nitrogen retention in broiler manure

A study was conducted to evaluate the effects of dietary nitrocompounds on bird performance, ammonia volatilization, and changes in manure nitrogen (N). A total of 200 one-day-old male chicks (Cobb 500) were used for this study. The chicks were raised in electrically heated battery brooders for 18 days. On day 1, birds were allocated into five treatment groups with four replicated pens: (T1) control, a corn and soybean meal diet (3,100 kcal kg^?1 metabolizable energy (ME) and 21% Crude Protein (CP)); (T2) 16.7 mg kg^?1 nitroethanol (NEL); (T3) 33.3 mg kg^?1 NEL; (T4) 16.7 mg kg^?1 nitropropanol (NPL); and (T5) 33.3 mg kg^?1 NPL. The body weight gain, feed intake and feed efficiency were measured on days 7, 14 and 18. Volatized ammonia (VA) and other N forms were measured at collection and following 2 weeks of incubation at 30°C. Broiler growth was not adversely affected by the nitrocompounds at concentrations up to 33.3 mg kg^?1. The results show that initial manure pH was reduced by adding nitroethanol (NEL) and nitropropanol (NPL) to the diet by 0.2 and 0.5 pH units, respectively. Total VA after 2 weeks was unaffected by dietary treatment. The amounts of uric acid decomposed and ammonia produced were closely balanced in the control sample. However, this balance was significantly different among the manures produced by birds receiving nitrocompound treatments. The inclusion of NEL and NPL resulted in the presence of measurable amounts of Xanthine not found in the control group. This study indicates that supplementation of nitroethanol or nitropropanol into broiler diets up to 33.3 mg kg^?1 influences uric acid degradation and ammonia production in broiler manure while maintaining optimal growth performance.