• Korean Journal of Agricultural Science
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• v.45 no.2
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• pp.185-196
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• 2018

The fungus gnat, Bradysia difformis, damages various crops in greenhouses and is recognized as an important pest around the world. Additionally, in the future, many other greenhouse crops will be added to the list of crops damaged by the fungus gnat. In this study, to find effective control methods for the fungus gnat, the insecticidal effect of 20 chemical synthetic insecticides was tested with the potato disc and pot treatment methods; additionally, the control effect of 16 strains of B. thuringiensis was examined with the potato disk method. The fungus gnat larvae were treated for 2 days with each of the synthetic insecticides to determine insecticidal effect using the potato disc method. The results were as follows. Among the highly insecticidal active pesticides, chlorfenapyr exhibited a 100% insecticidal activity, and fenazaquin, acetamiprid, dinotefuran, fenthion and thiamethoxam exhibited more than a 90% insecticidal activity. For the pot treatment method, chlorfenapyr exhibited a 3.3% insecticidal effect, and thiamethoxam, acetamiprid, dinotefuran, fenthion, etc. exhibited an insecticidal effect of less than 10% of the emergence rate to adult fungus gnat after 14 days of treatment. To select the B. thuringiensis strains that have an insecticidal effect on the fungus gnat, 16 strains were biologically assayed using the potato disc method. Among the 16 strains, Bt-3, Bt-8 and Bt-13 had more than a 70% insecticidal effect. The $LC_{50}$ and $LC_{95}$ values of Bt-3, Bt-8 and Bt-13 were $3.7{\times}10^5$ and $4.7{\times}10^8cfu/ml$, $1.4{\times}10^5$ and $1.1{\times}10^7cfu/ml$, and $1.4{\times}10^5$ and $1.3{\times}10^7cfu/ml$, respectively.

• Environmental Analysis Health and Toxicology
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• v.22 no.1 s.56
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• pp.27-36
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• 2007

Cyanides and dichlorophenols were important pollutants in industrial effluents of steel, petroleum, plastics, pesticides, synthetic dye and/or fiber manufacturing. The toxic effects of cyanide and 3, 5-dichlorophenol in the unary and binary solutions to Vibrio fischeri were determined using the newly developed $N-tox^{(R)}$ bioassay system. This bioassay system relies upon the attenuation of light intensity emitted by Vibrio fischeri exposed to various pollutants including metals and organic compounds. Most of studies dealing with toxicity of pollutants concerned single chemical species, while the organisms were typically exposed to pollutant mixtures. The present study showed that the toxicity of some binary combinations of cyanide and 3, 5-dichlorophenol significantly was lower than the predicted toxicity from the addicted model. This antagonistic interaction was well explained by chemical interaction model presented in this study.

• Korean Journal of Environmental Agriculture
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• v.33 no.3
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• pp.213-219
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• 2014

BACKGROUND: In an environment-friendly agriculture, plant extracts have been perceived as alternatives of synthetic pesticides. The Environment-friendly Agriculture Promotion Act of Korea has approved cinnamon extract as a matter for the production of commercial biopesticides. Thirteen commercial biopesticides containing cinnamon extract have been marketed locally. However, the analytical method for the quality control of these biopesticides containing cinnamon extract has not been studied. METHODS AND RESULTS: Cartridge clean-up method for the determination of cinnamaldehyde, cinnamylalcohol and salicylaldehyde in biopesticides containing cinnamon extract was developed and validated by gas chromatography (GC). The clean-up method was optimized with HLB SPE cartridges for the bioactive substance in biopesticides containing cinnamon extract, and the eluate was analyzed by GC. The developed method was validated, and the LOQ and recovery rates of cinnamaldehyde, cinnamylalcohol and salicylaldehyde were 0.139, 0.067 and $0.062mgL^{-1}$ and 84.2, 86.5 and 82.1%, respectively. The contents of cinnamaldehyde, cinnamylalcohol and salicylaldehyde were analyzed using the developed method in the 13 commercial biopesticides. Results showed 0.06-17.37%,

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.52-58
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• 2007

ALA (5-aminolevulinic acid) has been proposed as a tetrapyrrole-dependent photodynamic herbicide and insecticide by the action of the protoporphyrinogen IX oxidase (Protox IX). The present study was conducted to determine growth responses of plant and insects to ALA, biodegradable biopesticidal substance. In the paddy condition experiment, plant height and shoot fresh weight of barnyardgrass (Echinochloa crus-galli) was more reduced by ALA than rice plants, even though both plant species show great phytotoxicity. Hairy crabgrass (Digitaria sanguinalis), a monocot weed, was more sensitive to ALA at 5mM under upland condition when ALA applied on the foliage, compared with soybean (Glycine max) as a dicot crop. ALA solutions were tested for their insecticidal and larvicidal activities against Spodaptera exigua (Hubner) and Tetranychus urticae Koch. by foliar application and leaf-dipping method. The result showed higher insecticidal activity of ALA at 10mM and its mixture with insecticide luferon against S. exigua. Strongest insecticidal activity against T. urticae was observed from the ALA solution at 10mM 72 days after application. This results show that ALA solution had potent herbicidal and insecticidal activities against agricultural pests even though their activities were lower than those of synthetic pesticides.

• Korean Journal of Organic Agriculture
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• v.18 no.1
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• pp.83-92
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• 2010

Organic farming is a type of agricultural practices based on naturally occurring processes excluding or strictly limiting the use of synthetic fertilizers, pesticides, and other chemicals. This study was conducted to investigate the influences of agro-based materials, effective microorganisms (EM), liquid silicate (LS), and organic liquid fertilizer (OLF) for water dropwort (Oenanthe stolonifera DC.) cultivation. Soil pH, soil organic matter, and plant available phosphorous decreased with LS application. Exchangeable Ca and Mg decreased with EM application, and electrical conductivity and exchangeable Ca and K decreased with OLF application. Most of essential nutrient contents in water dropwort were reduced with the treatments of LS, EM, and OLF as compared with those in control plot, except nitrogen and phosphorus. However, diseases and insect pests were almost not observed in the water dropwort in the agro-based material application plots, except cluster caterpillar (Spodoptera litura). Productivity of water dropwort tended to be reduced: its higher productivity in the OLF and EM+LS plots and lower in the LS and control plots.

• Safety and Health at Work
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• v.9 no.2
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• pp.164-171
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• 2018

Background: In recent years, the interest in health and safety in the workplace has increased. Agriculture is one of the human work activities with the highest risk indexes. Studies on risk perception of agricultural workers are often referred to as specific risk factors (especially pesticides), but the risk perception plays an important role in preventing every kind of accident and occupational disease. Methods: The aim of this research is to test a new method for understanding the relation between risk perception among farmers and the main risk factors to which they are exposed. A secondary aim is to investigate the influence of training in risk perception in agriculture. The data collection was realized using a questionnaire designed to investigate the risk perception; the questionnaire was given to a sample of 119 agricultural workers in central Italy. Through the use of the "principal components analysis" it was possible to highlight and verify the latent dimensions underlying the collected data in comparison with scales of attitudes. Results: Results show that the highest percentage of strong negative attitude is among the people who have worked for more years, while farmers who have worked for fewer years have a marked positive attitude. Conclusion: The analysis of the questionnaires through the synthetic index method (Rizzi index) showed that agricultural workers involved, in particular the elderly workers, have a negative attitude towards safety; workers are hostile to safety measures if they have not attended special training courses.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1306-1315
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• 2017

DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane) is one of the organic synthetic pesticides that has many negative effects for human health and the environment. The purpose of this study was to investigate the synergistic effect of mixed cutures of white-rot fungus, Pleurotus ostreatus, and biosurfactant-producing bacteria, Pseudomonas aeruginosa and Bacillus subtilis, on DDT biodegradation. Bacteria were added into the P. ostreatus culture (mycelial wet weight on average by 8.53 g) in concentrations of 1, 3, 5, and 10 ml ($1ml{\approx}1.25{\times}10^9$ bacteria cells/ml culture). DDT was degraded to approximately 19% by P. ostreatus during the 7-day incubation period. The principal result of this study was that the addition of 3 ml of P. aeruginosa into P. ostreatus culture gave the highest DDT degradation rate (approximately 86%) during the 7-day incubation period. This mixed culture combination of the fungus and bacteria also gave the best ratio of optimization of 1.91. DDD (1,1-dichloro-2,2-bis(4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene), and DDMU (1-chloro-2,2-bis(4-chlorophenyl) ethylene) were detected as metabolic products from the DDT degradation by P. ostreatus and P. aeruginosa. The results of this study indicate that P. aeruginosa has a synergistic relationship with P. ostreatus and can be used to optimize the degradation of DDT by P. ostreatus.

• The Korean Journal of Pesticide Science
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• v.20 no.1
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• pp.7-13
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• 2016

As of many organochlorine pesticides, polychlorinated biphenyls are ubiquitous organic contaminants, which can be found in the most environmental matrices. Their toxic effects include endocrinedisrupting activity. Most researches with these toxicants performed with mixtures of congeners, namely Aroclor and related study has been done in complex environmental matrix, rather than single biosystems or pure congeners. 5 congeners were synthesized and their fates in pure microbial culture (Aspergillus niger) were determined in this study. Among biphenyl and synthetic congeners, biphenyl, PCB-1 (2-chlorobiphenyl), and PCB-3 (4-chlorobiphenyl) were rapidly transformed to hydrophilic metabolites, followed by PCB-38 (3,4,5-trichlorobiphenyl), while the degradation of PCB-126 (3,3',4,4',5-pentachlorobiphenyl) was not observed. The amounts of transformation for biphenyl, PCB-1, PCB-3, and PCB-38 were 65, 38, 52, and 2% respectively. The major metabolites of the above congeners were identified as mono- and di-hydroxy biphenyls, which are known to give adverse endocrinological effects.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1563-1570
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• 2010

To construct a highly sensitive detection system for endocrine disruptors (EDs), we have compared the activity of promoters with the n-alkane-inducible cytochrome P450 gene (ALK1), isocitrate lyase gene (ICL1), ribosomal protein S7 gene (RPS7), and the translation elongation factor-1${\alpha}$ gene (TEF1) for the heterologous gene in Yarrowia lipolytica. The promoters were introduced into the upstream of the lacZ or hERa reporter genes, respectively, and the activity was evaluated by ${\beta}$-galactosidase assay for lacZ and Western blot analysis for hER${\alpha}$. The expression analysis revealed that the ALK1 and ICL1 promoters were induced by n-decane and by EtOH, respectively. The constitutive promoter of RPS7 and TEF1 showed mostly a high level of expression in the presence of glucose and glycerol, respectively. In particular, the TEF1 promoter showed the highest ${\beta}$-galactosidase activity and a significant signal by Western blotting with the anti-estrogen receptor, compared with the other promoters. Moreover, the detection system was constructed with promoters linked to the upstream of the expression vector for the hER${\alpha}$ gene transformed into the Y. lipolytica with a chromosome-integrated lacZ reporter gene under the control of estrogen response elements (EREs). It was indicated that a combination of pTEF1p-hER${\alpha}$ and CXAU1-2XERE was the most effective system for the $E_2$-dependent induction of the ${\beta}$-galactosidase activity. This system showed the highest ${\beta}$-galactosidase activity at $10^{-6}\;M\;E_2$, and the activity could be detected at even the concentration of $10^{-10}\;M\;E_2$. As a result, we have constructed a strongly sensitive detection system with Y. lipolitica to evaluate recognized/suspected ED chemicals, such as natural/synthetic hormones, pesticides, and commercial chemicals. The results demonstrate the utility, sensitivity, and reproducibility of the system for identifying and characterizing environmental estrogens.

• Analytical Science and Technology
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• v.13 no.6
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• pp.722-730
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• 2000

The residual concentration and half-life time of synthetic pyrethroid insecticide cyfluthrin in potato and soil were investigated by gas chromatography (GC). The pesticide in potato was extracted with n-hexane, filtered and concentrated. The concentrated phase was transferred to the Sep-Pak silica gel column and purified with acetonitrile and acetone for the analysis by gas chromatography equipped with electron capture detector (GC-ECD). From the standard additional experiments with 0.01 and $0.1{\mu}g$, the recoveries were 85-87% and the detection limit was 0.005 ng. The soil sample was extracted with acetone and dichloromethane. The organic phase was concentrated and redissolved with n-hexane and analyzed with GC-ECD after cleaned with Sep-Pak column. From the standard additional experiments with 0.01 and 0.1 ng, the recoveries were 84-88% and the detection limit was 0.005ng. The half-life time of cyfluthrin in the silty clay was 25 days in the room laboratory and 0.6 days in the fieJd test whereas it was 38 days and 0.5 days for each in case of silty loam.