• Journal of Applied Biological Chemistry
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• v.65 no.3
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• pp.173-181
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• 2022

This study was carried out to investigate the residual characteristics of flubendiamide in kale to establish pre-harvest residue limits (PHRL) and the removal efficiency according to the washing solvent and method. Field tests were conducted at two different greenhouses, field 1 (Anseong-si, Gyeonggi-do) and field 2 (Incheon-si, Gyeonggi-do). According to the safe use guidelines kale was sprayed with flubendiamide twice every 10 days and harvested 0 (after 2 h), 1, 2, 3, 5, 7 and 10 days after the final application. The biological half-live of flubendiamide in kale was calculated based on dissipation curves of the pesticide in samples analyzed by liquid chromatography coupled with tandem mass spectrometry. In the analysis, method limits of quantitation (MLOQ) were 0.01 mg/kg, and recoveries performed with two different fortification levels of 10 MLOQ and maximum residue limit (0.7 mg/kg) were 104.2±3.6 and 101.9±10.2%, respectively. The dissipation rate constant of flubendiamide in kales were 0.2437 at field 1 and 0.1981 at field 2. PHRL calculation equations obtained using the dissipation constants estimated as follows: if the residual concentration of flubendiamide in kale on 10 days before harvest is less than 8.0 mg/kg, the residual concentration on the harvest would be under MRL. The removal of flubendiamide from kale was the greatest when it was washed with vinegar (39.8%), followed by baking soda (31.7%), calcium powder (30.2%), neutral detergent (27.2%), and tap water (15.9%). The results of this study would be useful for both farmers and consumers to produce or consume safe agricultural products.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.1
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• pp.22-26
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• 2014

This research was implemented to investigate pre-harvest sprouting characteristics in two Korean rice cultivars, Shindongjin (SDJ) and Hopum (HP). The panicles of both varieties were sampled after 15 days after heading (DAH) to 60 DAH at intervals of 5 days. As soon as sampled, the panicles were imbibed in water for 14 days at $25^{\circ}C$ to determine the vigor and germination ability of seeds according to location on panicle. To investigate the cause of non-germination of seeds in panicles, tetrazolium test and dormancy breaking were performed. The preharvest sprouting of HP started at 20 DAH while that of SDJ began at 30 DAH. The germination of seeds located in high rank branches within a panicle and the terminal seeds within a branch were earlier and faster and the germination patterns were same in both cultivars. The times at more than 50% of germination in a panicle were 35 DAH (57.0%) in HP and 45 DAH (56.8%) in SDJ. Preharvest sprouting was more than 80% at 50 DAH (82.6% of HP, 92.3% of SDJ) and more than 99% at 60 DAH (99.5%, 99.4%, HP and SDJ). These results indicated that the rate of PHS in a panicle increased with accumulation of the days after heading. The cause of non-germinated seeds at 15-25 DAH in panicle was immature embryo. After 30 DAH, however, when the non-germinated seeds were hulled, they started to germinate due to dormancy breaking, in which the germination percentage was higher in SDJ than HP. In conclusion, the pre-harvest sprouting varied according to days after heading, the seed position on panicle, and the dormancy intensity of varieties.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.267-274
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• 2020

The dissipation characteristics and kinetics of fungicide mandipropamid and insecticide thiamethoxam in lettuce under greenhouse conditions were investigated at three different lettuce-growing fields for estimating the pre-harvest residue limits (PHRLs). The analytical methods were fully validated for the quantitation of pesticide residues using High-Performance Liquid Chromatography-Photo Diode Array detector or Ultraviolet-Visible Detector and applied to real samples. The lettuces suitable for shipment were harvested during 10 days including pre-harvest interval after treatment at the recommended dose by safe-use guidelines. The initial mean residues in different fields were 6.68-17.87 and 4.96-8.31 mg/kg for mandipropamid and thiamethoxam, respectively, which decreased to 16-54 and 14-44% in 10 days. The clothianidin, a metabolite of thiamethoxam, was detected in <0.02 to 0.37 mg/kg. The dissipation of both pesticides followed first-order kinetics over a period of 10 days after application. Based on the residue data, the mean dissipation rate constant (λ) and biological half-lives (T_1/2) were estimated to be -0.1060 and 6.5 days of mandipropamid and -0.1236 and 5.6 days of thiamethoxam. The PHRLs for lettuce on the 10th and 5th day before harvesting were calculated to be 63.24 and 43.56 mg/kg for mandipropamid, and 44.66 and 25.88 mg/kg for thiamethoxam, with -0.0746 and -0.1091 of the upper 95% confidence intervals of dissipation rate constant, respectively. This work would be useful as guidance for adjusting the shipment date and contribute to stabilizing the income of farmers in Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.135-142
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• 2010

This study was carried out to establish the optimum pre-wilting time for the high-quality silage production of whole crop oat. Plants were harvested for three time at intervals of 10 days after heading (DAH) and silage production was conducted after the pre-wilting treatment of 0, 4, 8 and 32 hours, respectively. Results showed to attain a proper moisture content for profitable silage production, which was an optimal content for making silage, by pre-wilting oat for 4 hours after harvest at either 20 days after heading or harvesting 30 DAH(days after heading). As the feed value of silage, the processing of proper moisture contents showed that crude protein contents were high and the entire feed value showed higher than others. High content of lactic acid and the low content of acetic and butyric acid showed on 60~65% the moisture conditions of silage. There was desired that whole crop oat was pre-wilting on 4 hours and harvested at about 20~30 DAH and after that, even if harvesting at once, it was judged that it could produce good quality silage.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.149-155
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• 2002

Two pesticides commonly used for lettuce cultivation including chlorpyrifos and procymidone were subjected to a field residue trial to ensure safety of terminal residues in the harvest. After pesticides were applied at standard and double rates in a foliar spray, leaf persistence of their residues was investigated far 10 days prior to harvest. Even though far exceeded the tolerances, initial leaf residues were rapidly dissipated with time and remained only 0.4$\sim$7.2% of the residues in the harvest. As well fitted by the first-order kinetics, biological half-lives of the pesticide residues in lettuce leaves ranged 1.2$\sim$2.6 days. Slow dissipation of the residues in the harvest was observed during storage at room temperature and 4$^{\circ}C$ for 7 days. Portions of dislodgeable residues which resided in detergent washings decreased as time elapsed. Patterns in dissipation and distribution of dislodgeable residues were not largely affected by the application rate of pesticides. It is concluded that timing of pesticide application, that is, pre-harvest interval would be the first factor to determine the terminal residue level in edible portions of lettuce.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.246-246
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• 2022

• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.132-132
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• 2023

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.04a
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• pp.15-15
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• 2022

• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.155-161
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• 2013

The residue patterns of clothianidin and thiacloprid, insecticides registered in the ginseng, were investigated to predict pre-harvest residues limits (PHRL). Pesticides were treated under Korea GAP (Good Agricultural Practices) with the recommended dose (single dose) and twice of recommended dose (double dose). Samples were collected 11 times over 42 days (each 0, 2, 5, 8, 12, 16, 20, 24, 28, 33, 42 days after treatment). Residues of clothinidin and thiacloprid were analyzed by UPLC/TQD. Biological half-life of clothinidin in single dose and double dose were 14.6 days and 10.2 days and that of thiacloprid were also 9.7 days and 11.2 days, respectively. The PHRL of ginseng on 10 days before harvest was 0.3 mg/kg in clothianidin and 0.18 mg/kg in thiacloprid.

• The Korean Journal of Pesticide Science
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• v.21 no.1
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• pp.62-67
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• 2017

In this study, the residue patterns of flubendiamide and pyriofenone registered in the strawberry were investigated to predict pre-harvest residue limit (PHRL). The samples were harvested at 0, 1, 2, 3, 5, 7, 10 days after treatment and the pesticide residues were analyzed by HPLC/UVD. The limit of quantification (LOQ) was $0.01mg\;kg^{-1}$ for flubendiamide and pyriofenone. The recovery levels of flubendiamide and pyriofenone were $90.9{\pm}2.2%$ and $81.9{\pm}0.8%$, $87.7{\pm}2.1%$ and $85.3{\pm}1.1%$ for spiked levels of 0.01 and $0.1mg\;kg^{-1}$, respectively. The values of biological half-lives for field 1 and field 2 were 8.1 and 7.2 days for flubendiamide, 7.0 and 6.9 days for pyriofenone. According to these results, we recommends the level of PHRL on strawberry for flubendiamide and pyriofenone as 1.87 and $3.76mg\;kg^{-1}$ at 10 days before harvest, respectively.