Dissipation and Residues of Myclobutanil in Tobacco and Soil Under Field Conditions

Field experiments were conducted in two different locations to determine the dissipation pattern and residue levels of myclobutanil in tobacco leaves and soil. Myclobutanil 12.5 % microemulsion (ME) formulation was sprayed once at 3.0 mL/ha, and the residues in green tobacco leaves dissipated to more than 50 % of the initial deposits 5 days after application and up to above 90 % after 21 days. The dissipation rate of myclobutanil in soil was lower than that in green tobacco leaves. The residues dissipated above 50 % of the initial deposits 7 days after treatment and dissipated about 90 % after 42 days. The calculated half-life values (T _1/2) were found to be 4.89–6.77 days in green tobacco leaves and 12.88–19.20 days in soil, respectively. The ultimate residues of myclobutanil in flue-cured tobacco leaves and soil were determined after the third and fourth applications at levels of 2.0 and 3.0 mL/ha. Myclobutanil residues in cured tobacco leaves 21 days after the last treatment ranged from 0.85 to 3.27 mg/kg. Meanwhile, the residues detected in soil reached below 0.045 mg/kg 21 days after the last treatment.     

Dissipation of Chlorfenapyr Residue in Pakchoi and Soil

No abstract available.     

Dissipation and Residue of Forchlorfenuron in Citrus Fruits

Field trials were carried out in three provinces of China to study the dissipation and residue of forchlorfenuron in citrus fruits. The results had shown that the degradation rate of forchlorfenuron in citrus fruits followed the first-order kinetics equation C = A·e^Bt. The half-lives of forchlorfenuron were 15.8–23.0 days, the final residues of forchlorfenuron in pulp were all ≤0.002 mg/kg, and most of the residues were concentrated in the peel. The risk assessment revealed that no significant potential health risk would be induced by forchlorfenuron in citrus fruits. Therefore, it could be safe to apply forchlorfenuron in citrus fruits, and the results of this study could also be regarded as a reference to the setting of maximum residue limit for forchlorfenuron in citrus fruits in China.     

Dissipation and Residue of Cyprodinil in Strawberry and Soil

The dissipation of cyprodinil under field and greenhouse condition in China was investigated. The pesticide cyprodinil dissipation differed under different cultivate conditions, the half lives were 14.5 and 12.5 days in strawberry and soil, respectively, under the field condition, 5.5 and 6.5 days, respectively, under greenhouse. The results showed that the dissipation rate under greenhouse condition was much faster than under field condition either in strawberry or soil. The terminal residues in strawberries were below the EU maximum residue level (5 mg/kg) after 7 days of application. This study will give a suggestion for the reasonable use of cyprodinil under different cultivate conditions and can also provide reference to set MRL value in strawberry in China.     

Dissipation and Residue of Thiacloprid in Cabbage and Soil

Residue dynamics of thiacloprid in cabbage and soil was studied in this paper utilizing liquid chromatography with tandem mass spectrometry (LC–MS/MS). The field trial was conducted in two sites: Beijing, China and Hubei, China. Thiacloprid dissipated rapidly with the half-life 1.3–1.6 days in cabbage and 2.1–3.1 days in soil. In the terminal residue experiment, no higher residue than 0.06 mg/kg in cabbage and 0.16 mg/kg in soil was detected, which was far below either EU MRL (0.2 mg/kg) or Japan MRL (1 mg/kg).     

Residue and Dissipation Dynamics of Flusilazole in Apple and Soil

A simple, quick and reliable residue analytical method for flusilazole in apple and soil was developed in this study. The samples were extracted with acetonitrile and determined by liquid chromatography with UV detection. The LOQ of the method was 0.02 mg/kg. The dissipation dynamic and final residues of flusilazole in apple and soil were studied using field trial method. The results of residual dynamics experiment showed that after the apple was treated by flusilazole at treble of recommended high dosage (3.75 g/kg H₂O), the half-life times of flusilazole in apple and soil were 4.23–7.77 days and 3.04–5.14 days, respectively. Residues of flusilazole in apple at harvest time were all below 0.05 mg/kg at both recommended high dosage and 1.5 times of recommended high dosage.     

Dissipation and Residue of Bifenthrin in Wheat under Field Conditions

Field trials were carried out to investigate the dissipation and residue levels of bifenthrin in wheat. After extraction with acetonitrile, the samples were cleaned up by dispersive solid-phase extraction and detected by gas chromatography–mass spectrometry. The half-lives of bifenthrin in wheat seedlings ranged from 2.4 to 10.5 days. At harvest time, the terminal residues of bifenthrin were below the maximum residue limit (0.5 mg/kg) set by Codex Alimentarius Committee or European Union in wheat grain, which suggested that the use of this pesticide was safe for humans. However, the relatively high residue levels of bifenthrin in wheat straw should be paid attention to.     

Dissipation and Residue of Spinosad in Zucchini Under Field Conditions

The dissipation and residue of the insecticide spinosad in zucchini were investigated. An ultra-performance liquid chromatography–tandem mass spectrometry analytical method was developed for spinosad analysis. The half-lives of spinosad were 3.5–3.9 days in zucchini and 3.6–4.1 days in soil. The results showed that the dissipation rate of spinosad was fast, and it is suggested that a combination of rapid growth of zucchini, photodecomposition and the activity of soil microorganisms affected the dissipation rate of spinosad. The terminal residues of spinosad in zucchini were all below the quantification limit. No residue limit currently exists for spinosad in zucchini in China and other countries. Thus, the results can be useful in establishing a maximum residue limit.     

Dissipation of Mefenoxam Residue in Watermelon and Soil Under Field Conditions

Mefenoxam is the systemic phenylamide fungicide, which is widely used in controlling phytophthora disease of tomato, cucumber, pepper and watermelon, etc. The dissipation behaviour of mefenoxam residues in watermelons and soils was studied. The whole watermelon, melon flesh and soil matrices of mefenoxam were analyzed by GC–NPD. At three different spiking levels mean recoveries and relative standard deviation from spiked samples in six replicated experiments for each matrix were in the range 89.6–98.2% and 1.5–8.1%, respectively. Under field conditions, mefenoxam dissipation rate was found to be faster in the whole watermelons than in the soils. The results showed that the half lives in whole watermelon and soil from Beijing were 3.9 and 10.0 days, respectively, and the half lives in whole watermelon and soil from Shanxi were 3.7 and 28.4 days.     

Dissipation and Residue of Rotenone in Cabbage and Soil Under Field Conditions

Rotenone dissipation and terminal residue in cabbage and soil under field conditions were determined by high-performance liquid chromatography. The dissipation rates of rotenone were described using first-order kinetics. The half-lives ranged from 0.89 to 1.55 days in cabbage and 1.98 to 2.76 days in soil. Prolonged pre-harvest interval times ensure that the cabbage is safe for consumption. Temperature and the physico-chemical properties of the soil were identified as the key factors affecting rotenone degradation in cabbage and soil under field conditions.     

Dissipation and Residue of Acetamiprid in Watermelon and Soil in the Open Field

Residue dynamics of acetamiprid in watermelon and soil was studied in this paper utilizing liquid chromatography with tandem mass spectrometry (LC–MS/MS). The LODs for acetamiprid in whole watermelon, melon flesh and soil were 0.002 mg/kg. The fortified recoveries ranged from 73.7 % to 107.5 % with relative standard deviations (RSDs) of 1.7 %–5.9 %. Acetamiprid dissipated in watermelon and soil with the half-life 3.12–3.92 days and 1.18–1.46 days in two locations Beijing and Shandong provinces, respectively. In the terminal residue experiment, no higher residue than 0.01 mg/kg in melon flesh and 0.3 mg/kg in whole watermelon and soil were detected.     

Residue and Dissipation Dynamics of Lufenuron in Tomato Fruit Using QuEChERS Methodology

One field experiment was conducted with lufenuron (Match^® 5 % EC) on tomato crop during August 2011. The main objective was to understand the residue and dissipation behavior of insecticide lufenuron in tomato fruit samples. The dissipation behavior of lufenuron insecticide followed first-order rate kinetics at standard recommended dose application. The average initial deposit of lufenuron in tomato was observed to be 1.299 mg kg⁻¹at single application rate. This lufenuron residue dissipated to bellow LOQ of 0.03 mg kg⁻¹ 21 days after the treatment. Lufenuron residues were lost with pre-harvest intervals of 7 days, following application at the recommended dose by manufacture.

     

Dissipation Rate and Residue Distribution of Dufulin in Tomato and Soil Under Field Conditions

Dissipation rate and residue distribution of dufulin in tomato and soil under field conditions were investigated in Guiyang, Tianjin, and Haikou during 2011–2012, using ultra-performance liquid chromatography. Average recoveries of dufulin in tomato and soil ranged from 91.03 % to 95.16 % and 94.35 % to 98.34 %, respectively, with relative standard deviations of 1.16 %–3.97 %. Dufulin dissipation followed first-order kinetics. Dufulin had half-lives of 2.8, 4.7, and 9.0 days in tomato and 6.1, 8.2, and 17.2 days in soil in Guiyang, Tianjin, and Haikou, respectively. At harvest, dufulin residues in tomato samples collected 5 days after the last application at 3 times recommended dosage applied every 5 days were below 1.0 mg kg^?1.     

Dissipation of Oxaziclomefone and Residue Analysis in Rice,Soil and Water Under Field Conditions

The analytical method for the residue analysis of a novel herbicide, oxaziclomefone, and its dissipation in soil, water, rice plants and husked rice in rice fields at GAP (Good Agricultural Practices) conditions were studied. Oxaziclomefone residues were determined by GC-NPD. Mean recoveries ranged from 84.4 to 108.2% with relative standard deviations (RSDs) of 2.4 to 17.2% at three different spiking levels for each different matrix. The limits of quantification (LOQ) were found to be 0.01 mg/kg in soil, water, rice plants and husked rice and 0.02 mg/kg in rice hull. The mean half-lives of oxaziclomefone residues in water, soil and rice plants were 11.3, 37 and 4.4 days, respectively. At harvest, soil, straw, rice hull and husked rice samples were found to contain oxaziclomefone below the maximum residue level (0.1 mg/kg) set by Japan and Korea. Following the recommended application method, this herbicide is therefore safe to apply to rice fields.     

Determination and Study on Residue and Dissipation of Florasulam in Wheat and Soil Under Field Conditions

The residue and dissipation of florasulam in wheat and soil were determined by high performance liquid chromatography–tandem mass spectrometry. The dissipation half-lives for florasulam in soil were 0.66 days in Zhejiang and 0.64 days in Hebei. In wheat plant, half-lives of florasulam were 5.16 days in Zhejiang and 2.07 days in Hebei. The residues of florasulam in wheat grain, wheat straw and soil were below the detection limit (i.e., 0.01 mg/kg, the maximum residue level of florasulam). These results would be helpful in setting MRL guidance of florasulam in wheat in China.     

Dissipation Study of Thiophanate Methyl Residue in/on Grapes (Vitis vinifera L.) in India

A multi-location field trial was conducted in India during 2006–2008 to evaluate the dissipation pattern of thiophanate methyl (75% WP) in/on grapes at two application rates (500 and 1,000 g a.i. ha^?1). The quantitative analysis of the fungicide residues as carbendazim was performed using a UV/VIS spectrophotometer at the maximum absorption band of 281 nm. The average recovery was found 87% and the relative standard deviations (RSD) were below 3.8%. Following the first order kinetics the fungicide dissipates in grapes with a half-life (t _½) value of 4.74–6.52 days irrespective of locations and doses.     

Dissipation and Residue of <Emphasis Type="Italic">S</Emphasis>-metolachlor in Maize and Soil

The purpose of this article was to establish a simple residue analysis method for S-metolachlor in maize and to study its dissipation and residue in maize field eco-system. The results showed that S-metolachlor declined rapidly in maize seedling and soil after application. The half-lives of S-metolachlor in maize seedlings in Beijing and Changchun were 6.68 and 4.85 days, respectively, and in soil were 12.81 and 14.81 days, respectively. The terminal residues of S-metolachlor in soil samples were very low (around 0.005-0.045 mg/kg), and the residues in maize seeds were not detectable. The use of S-metolachlor according to the recommended dosages in maize could be considered safe.     

Dissipation of Penconazole in Tomatoes and Soil

Dissipation of penconazole was estimated in tomatoes fruits cultivated in field using QuEChERS method for sample preparation and high performance liquid chromatography with diode array detector. Following one application of normal dose 25 mL 100 L⁻¹ water, the average initial deposits of penconazole were observed to be 0.74 and 1.21 mg kg⁻¹ for tomatoes fruits and soil, respectively. The residues dissipated below the maximum residues limit of 0.2 mg kg⁻¹ after 15 days. The half-life value (T1/2) and preharvest interval of penconazole were 5.61 and 15 days, respectively. While (T1/2) of penconazole in soil was 15.51 days. Thus, a waiting period of 15 day was suggested for the safe consumption of penconazole treated Tomatoes.     

Dissipation of Chlorantraniliprole in Tomato Fruits and Soil

The main objective of this study was to understand the residue and persistence behaviour of new insecticide chlorantraniliprole in tomato fruit and soil samples. Its residue was analyzed by HPLC and it dissipated in tomato fruit and soil following first order kinetics. The results showed half life (t_1/2) value of 3.30 and 3.66 days for chlorantraniliprole in tomato fruit and soil, respectively. According to maximum residue limit (MRL) the pre-harvest interval (PHI) of chlorantraniliprole on tomato was 8-days after the treatment.     

Dissipation and Residues of Emamectin Benzoate in Cabbage

Emamectin benzoate residue dynamics and final residues in supervised field trials at GAP conditions were studied. An HPLC–MS analytical method for the determination of emamectin benzoate in cabbage and soil was developed. The recoveries of emamectin benzoate on cabbage and soil were observed from 71 % to 102 % at fortification levels of 0.01, 0.1 and 1.0 mg/kg. The reported limit of quantification (LOQ) was found to be 0.01 mg/kg. The dissipation experiments showed the half-lives (T_1/2) of emamectin benzoate was around 1 days. At pre-harvest intervals (PHI) of 7 and 12 days, emamectin benzoate residue was observed to be below the LOQ.