• Korean Journal of Environmental Agriculture
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• v.42 no.2
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• pp.93-103
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• 2023

Persistence and degradation patterns of acequinocyl and its metabolite, hydroxyl-acequinocyl (acequinocyl-OH) and fenpyroximate in butterburs (Petasites japonicus Max.) were investigated after pesticide application. Butterburs, one of the minor crops in South Korea, was planted in two plots (plot A for double and plot B for single application) in a greenhouse. Butterburs samples were also planted in a separate plot without pesticide treatment, as the control. A commercial pesticide containing acequinocyl and fenpyroximate was applied to the foliage of butterburs at hourly intervals after dilution. Recoveries of acequinocyl and acequinocyl-OH were 78.6-84.7% and 83.7-95.5%, respectively; the relative standard deviation of the two compounds were less than 5%. The method limit of quantification was 0.01 mg/kg. The total (Ʃ) acequinocyl residues in butterburs reduced by 96.0% at 14 days and 75.9% at 7 days, in plot A and B, respectively, after final pesticide applications. The biological half-life (DT₅₀) of Ʃ acequinocyl and fenpyroximate, calculated using the dissipation rate, was 3.0 days and 4.0 days, respectively. These data were used to set up maximum residue and safe standard levels when the pesticides are applied to control pests during butterbur cultivation. Risk assessment results showed that the maximum % acceptable daily intake was 7.74% for Ʃ acequinocyl and 0.16% for Ʃ fenpyroximate. The theoretical maximum daily intake of Ʃ acequinocyl and fenpyroximate was 26.3% and 35.8%, respectively. In conclusion, the concentrations of Ʃ acequinocyl and fenpyroximate in butterburs pose no significant health risks to Koreans.

• The Korean Journal of Pesticide Science
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• v.13 no.2
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• pp.98-104
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• 2009

This study was carried out to investigate the residue patterns of two neonicotinoid insecticides, dinotefuran and thiacloprid, commonly used for cucumber, were subjected to indicate a residual characteristic under greenhouse conditions. The pesticides were sprayed onto the crop at recommended and double doses 7 days before harvest and then sampling was done 0, 2, 3, 5, and 7 days after spraying. The amounts of their residues in the crop were analyzed with an HPLC. Their detection limits were 0.01 mg/kg for dinotefuran and 0.005 mg/kg for thiacloprid. Mean recoveries of dinotefuran and thiacloprid were from 85.78 to 89.52 and from 85.71 to 95.31%, respectively. Half-lives of dinotefuran and thiacloprid were 2.8 and 1.8 days at the recommended dose and 2.8 and 1.5 days at the doubled dose, respectively. The ratios of the EDI to ADI by intake the crop harvested 7 days after spraying were less than 0.1% of their ADIs.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.14-21
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• 2015

To determine residual characteristics of azoxystrobin in ginseng under different cultivation conditions such as use of straw mat on cultivation soil and filling gap between ginseng stem and soil surface and also to elucidate its approximate behavior after spraying, 20% azoxystrobin suspension concentrate solution was sprayed 4 times onto 5-year-old ginseng with 10 days interval at a application rate of about 200 L/10 a and then residues in samples were analyzed. The residue level was lower in case of use of straw mat and filling the gap with soil than in case of no use of straw mat and no filling the gap, representing that use of straw mat and filling the gap with soil were contributed to decrease of pesticide residues in ginseng. A large portion of the test pesticide distributed onto ginseng leaf with a higher specific surface area. The amounts of azoxystrobin residues decreased in ginseng leaf, while increased on soil surface, as close to harvest. About 0.1% of azoxystrobin sprayed was distributed in ginseng root and 12.7-20.4% (mean 16.6%) of azoxystrobin could be decreased for dietary intake by removing of rhizome from ginseng root before intake.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.61-66
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• 2010

Corn stalk, one of the most abundant agricultural residue in the world, was examined in this study to use it as an alternative fiber source of wood fiber. In order to find the proper way to utilize corn stalk more efficiently, the morphological properties and the papermaking properties of the, bast fibers and the corn pith, were evaluated respectively. Although the bast fiber fraction showed comparable properties to those for hardwoods in the fiber properties and the papermaking properties, the pith resulted in low brightness and low drainage rate. But the short and flexible fibers in pith fraction led to dense and compact handsheet structure, correspondingly the higher sheet strength. There big differences in properties between bast fiber and pith should be considered for the fully utilization of corn stalk.

• Carbon letters
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• v.26
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• pp.66-73
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• 2018

We assessed the effects of combining bio-char with straw residue mulching on the loss of soil soluble nutrients and citrus yield in sloping land. The two-year study showed that straw residue mulching (ST) and bio-char application combined with straw residue (ST+BC) can significantly reduce soil soluble nutrient loss when compared with the control treatment (CK). The comparative volume of the soil surface runoff after each of the treatments was as follows: CK > ST > ST + BC. Compared with the CK, the runoff volume of the ST was reduced by 13.6 % and 8.5 % in 2014 and 2015, respectively. Compared with the CK, combining bio-char with the ST application reduced the loss of soluble nitrogen and improved the soil total nitrogen content reaching a significant level in 2015. It dramatically increased the soil organic matter content over the two year period (36.3% in 2014, 50.6% in 2015) as well as the carbon/nitrogen ratio (C/N) (16.6% in 2014 and 39.3% in 2015). Straw mulching combined with bio-char showed a trend for increasing the citrus yield.

• Journal of Mushroom
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• v.12 no.4
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• pp.367-370
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• 2014

In this study, we attempted to find substitute materials, distillers residue of cassava, alfalfa pellet, and distillers residue of corn, for cotton seed meal in bottle cultivation of Pleurotus ostreatus. In all treatments, the total carbon content was comparable with the exception of T4, and the total nitrogen content of T3 was similar to the control group, and C/N ratio of T4 was higher than other treatments. The diameter of plieus was the largest in T2, and the diameter of stipe was the largest in T2 and T4. And the length of stipe was largest in T1 and T2, and the most number of available stipes was in T1 and T3. The yield and bio-efficiency of fruit-body by residue of corn with soluble treatment(T3), were similar to the control of P. ostreatus. Therefore, it was suggested that residue of corn was substituted for cotton seed meal for cultivation of P. ostreatus.

• International Journal of Industrial Entomology and Biomaterials
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• v.31 no.2
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• pp.79-84
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• 2015

A new cecropin-like antimicrobial peptide (Px-CLP) gene was isolated from the immunechallenged larvae of the swallowtail butterfly, Papilio xuthus, by employing annealing control primer (ACP)-based GeneFishing PCR. The full-length cDNA of Px-CLP is 310 nucleotides encoding a 70 amino acid precursor that contains a putative 22-residue signal peptide, a 4-residue propeptide, a presumed 37-residue mature peptide, and an uncommon 7-residue acidic pro-region at the C-terminus. The deduced amino acid sequence of Px-CLP showed significant identities with other Lepidopteran cecropin D type peptides. RT-PCR revealed that the Px-CLP transcript was detected at significant level after injection with bacterial lipopolysaccharide (LPS). The peptides with or without C-terminal acidic sequence region were synthesized on-solid phage and submitted to antibacterial activity assay. The synthetic 37-mer peptide (Px-CLPa), which removed C-terminal acidic sequence region, was showed exclusively antibacterial activity against E. coli ML35; meanwhile, a 44-mer peptide (Px-CLPb) with C-terminal acidic peptide region was not active. This result suggests that Px-CLP is produced as a larger precursor containing a C-terminal pro-region that is subsequently removed by C-terminal modification.

• Current Research on Agriculture and Life Sciences
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• v.31 no.4
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• pp.272-279
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• 2013

The dissipation patters of the triazole fungicides flusilazole and myclobutanil in apples were investigated to establish the biological half-lives and pre-harvest residue limits (PHRLs). The residual amounts of the fungicides sprayed with single or triple doses were below the maximum residue limits (MRL) for apples established by Ministry of Food and Drug Safety. The dissipation constants of the fungicides in the apples were 0.0513 for flusilazole and 0.0244 for myclobutanil meaning their biological half-lives were calculated as 6.2-6.7 days for flusilazole and 13.3-24.8 days for myclobutanil. The PHRLs calculated using the dissipation constants indicated that the residual amounts of flusilazole and myclobutanil in the apples at the harvesting date would be below the MRLs if their residual amounts were 0.43 and 0.59 mg/kg, respectively, at 7 days prior to harvesting the apples.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.1
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• pp.67-74
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• 1997

This experiment was conducted in 1992 and 1993 at the forage experimental field, College of Agriculture and Life Sciences, Seoul National University, Suweon to determine timing of rye(Secde cemde L.) harvest and residue chemical treatment prior to tillage in minimizing the adverse effects of the rye residue on growth and yield of succeeding corn(Zea muys L.). Eight treatments were established in 1993 which included four treatments such as no paraquat (1, l'diiethyl- 4, 4'-bipyridinium dichloride), paraquat treatment at 10, 23, and both 23 and 10 days prior to tillage when rye was harvested on April 14, and another four treatments such as no paraquat, paraquat treatment at 1, 5 and 10 days prior to tillage when rye was harvested on April 26. No paraquat treatment significantly resulted in reductions in corn plant height on June 3 and 10 when rye was harvested on April 14, but differences in the plant height and leaf number of corn among treatments were generally nonsignificant. Corn LA1 and silk emergence were not affected by paraquat treatment times regardless of rye harvested dates, but silk emergence was delayed by 1 to 2 days with no paraquat when rye harvested on April 14. Corn dry matter and TDN yields were significantly increased by paraquat treatment at 10 and 5 days prior to tillage treatment when rye was harvested on April 14 and 26, respectively, but other agronomic characteristics such as dry matter percentage, ear percent to total dry matter, and stover and ear yields of corn at harvest showed little or no response to paraquat treatment times.

• The Korean Journal of Pesticide Science
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• v.16 no.3
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• pp.217-221
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• 2012

This study was carried out to evaluate residual characteristics of tolclofos-methyl in ginseng and elucidate the reason for its high detection rate from fresh ginseng selling at markets. Seeds of ginseng were sowed after seed dressing with tolclofos-methyl and after a year of growth, the young seedlings were transplanted to field. They were then harvested annually until three-years of growth and the pesticide residue was analyzed in them. LOD and LOQ of the pesticide were 0.001 and 0.003 mg/kg, respectively. Recovery test was carried out to validate the analytical method for tolclofos-methyl in ginseng. The ginseng seedlings were fortified with the test pesticide at the level of LOQ, ten times of LOQ and maximum residue concentration of tolclofos-methyl. Its recovery ranged from 77.37 to 100.16%. Residual concentration of tolclofos-methyl in ginseng seedlings just before transplanting and two-year-old ginseng were from 7.58 to 8.05 and from 6.46 to 6.79 mg/kg, respectively. In case of three-year-old ginseng, it was found to be from 4.18 to 4.35 mg/kg. As a result of annual pesticide residue analysis, concentration of the pesticide was found to decrease time-coursely in ginseng. This may be due to decomposition and increasing of fresh weight of the ginseng during the cultivation periods of three years.