• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.39-44
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• 1998

Three pesticides for paddy rice, iprobenfos, isoprothiolane, and diazinon were examined on some environmental factors, their hydrolysis, microbial degradation, and photolysis in aqueous systems. Iprobenfos was mainly degraded by microorganisms and its half-life was 5.7 days at $28^{\circ}C$ in aqueous systems. Hydrolysis of iprobenfos was accelerated by the higher temperature, but its photodegradation was accelerated by the lower pH. Isoprothiolane was rapidly decomposed by two factors, microorganisms and sunlight. The half-life of isoprothiolane by sunlight was 91 days at pH 9.0, while it was 13 days at pH 4.0 and 16 days at pH 7.2. However, it was shortened under low pH condition. In aqueous system, diazinon was degraded by all of three factors and its degradation rate was remarkably accelerated by acidic solution. Main degradation factors of iprobenfos, isoprothiolane, and diazinon in the aqueous system were investigated by microbial degradation, photolysis, and hydrolysis, respectively. The strains of microbial degradation for iprobenfos, isoprothiolane, and diazinon in the aqueous environment were identified as Pseudomonas putida, Alcaligenes xylosoxydans ss, Klebsiella planticola/ornithinllytica, respectively. The similarity rates of identity were $54.8{\sim}86.2%$ with biolog-system.

• The Plant Pathology Journal
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• v.20 no.4
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• pp.244-246
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• 2004

Sectors of rice blast fungus, Pyricularia grisea, frequently appeared on potato dextrose agar amended with edifenphos and iprobenfos. Thus, we assessed the sector-forming frequency of isolates of P. grisea and compared the fungicide sensitivity between wild types and sectors against the fungicides. The 905 isolates of the fungus were obtained from rice-growing locations in Korea from 1997-1998. When the isolates were grown on potato dextrose agar amended with minimal inhibitory concentrations of edifenphos (20 ${\mu}$g a.i./ml)and iprobenfos (55 ${\mu}$g a.i./ml), they produced sectors that overcame the effect of the fungicides. Among the 905 isolates tested, 9.0% produced sectors against edifenphos and 5.6%, against iprobenfos. Different sector-forming frequencies were also observed among the 11 locations of Korea. Sectors obtained from the fungicide-amended media generally grew more than their counterpart wild types grown on the media with either edifenphos or iprobenfos, regardless of their origins. In this study, greater relative growth of sectors over wild types of tested isolates can support the resistant characteristic of the fungus to survive against the fungicides. Therefore, the results indicate that the sectoring in rice blast fungus, P. grisea, may play a role in the occurrence of fungicide resistance.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.309-319
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• 2002

Soil adsorption study was carried out to define the mobility of pesticides or to evaluate leaching potential in soils. Five pesticides including ethoprophos, procymidone, iprobenfos, isoprothiolane, and butachlor were subjected to optimized adsorption experiment protocol for three types of cultivation soils. Freundlich adsorption coefficients (K) were ranged $0.35{\sim}0.95$ for ethoprophos, $0.98{\sim}2.2$ for iprobenfos, $1.2{\sim}4.3$ for procymidone, $1.5{\sim}3.5$ for isoprothiolane and $7.9{\sim}19$ for butachlor in three soils. Based on Koc values, ethoprophos was classified as mobile, iprobenfos, isoprothiolane and procymidone as moderately mobile and butachlor as slightly mobile. Two evaluation methods, Groundwater Ubiquity Score (GUS) index and standard indices of soil-chemical adsorption and biodegradation, were used for the estimation of pesticide leaching potential. Leachability of isoprothiolane and iprobenfos were evaluated as moderate, ethoprophos as a little potential, while butachlor and procymidone showed very low leaching potential. The leaching potential of pesticides was essentially determined on the basis of intrinsic properties of the pesticides and environmental properties. Among the soil properties, organic matter gave a great influence on the leachability of soils. Therefore, leachabilities of pesticides were expected less in loam with relatively higher organic matter than clay loam with lower organic matter.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.311-315
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• 2005

The simultaneous or consecutive product analysis is needed for quality control because the various items are produced in pesticide manufacturer. This study was conducted to establish a multi-pesticide analysis making possible to analyze several active ingredients with one injection of mixed active ingredients under same instrument-condition in the cause of quality control with accuracy and speed. The test was conducted with 3 pesticides, iprobenfos 17%GR, isoprothiolane 12%GR, tebufenozide 20%SC and performed by GLC and HPLC. With the GLC method, 2 active ingredients of iprobenfos and isoprothiolane were analyzed but tebufenozide was not detective simultaneously. With the HPLC method, all of the active ingredients in those three pesticides were simultaneously analyzed in this study.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.300-308
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• 2002

This study was conducted to investigate the downward mobility of pesticides using soil colunms and to compare the experimental results with predicted values from Convective mobility test model. Five pesticides including ethoprophos, procymidone, iprobenfos, isoprothiolane, and butachlor were subjected to soil column leaching test for three types of cultivation soils. The concentrations of ethoprophos, iprobenfos, procymidone, isoprothiolane and butachlor leached from soil column of 30 cm depth ranged $0.74{\sim}3.61mg/mL,\;0.36{\sim}1.67mg/L,\;0.16{\sim}0.84mg/L,\;0.16{\sim}0.67mg/L$ and lower than 0.15 mg/L, respectively. Elution volume to reach the peak of ethoprophos, iprobenfos, procymidone, isoprothiolane and butachlor in the leachate ranged $2{\sim}4PV,\;3{\sim}10PV,\;5{\sim}13PV,\;4{\sim}14PV\;and\;19{\sim}61PV$, respectively. Convection times predicted by Convective mobility test model at standard conditions were $9{\sim}18$ days for ethoprophos, $17{\sim}35$ days for iprobenfos, $24{\sim}54$ days for isoprothiolane, $21{\sim}65$ days for procymidone and $105{\sim}279$ days for butachlor. Based on these convection times, ethoprophos was classified as mobile or most mobile, isoprothiolane and procymidone as moderately mobile or mobile and butachlor as slightly mobile. On the same conditions, convection times from the model were coincided with those from soil column test in most of the soil-pesticide combinations applied. Therefore, Convective mobility test model could be applied to predict convection times of pesticides.

• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.132-137
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• 2008

Differential gene expression profiling was carried out in the hepatic tissue of medaka fish, Oryzias latipes, after exposure to an organophosphorus pesticide (OPP), Iprobenfos (IBP), a widely used pesticide in agri- and fish-culture, using a medaka cDNA micro array. Twenty six kinds of differentially expressed candidate genes, with 15 and 11 induced and repressed in their gene expressions, respectively, were associated with cytoskeleton (3.8%), development (7.7%), immune (7.7%), metabolism (30.8%), nucleic acid/protein binding (42.3%) and reproduction (7.7%). Of these genes, changes at the transcription level of five were re-evaluated by real-time quantitative PCR (qRT-PCR). Considering the known function of authentic genes, the effects of IBP on the biological activity and pathological aspects in medaka fish were discussed. The identified genes could be used as molecular biomarkers for biological responses to OPPs contamination in an aquatic environment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.58 no.4
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• pp.393-398
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• 2013

Lodging in the direct seeded rice cultivation on flooded paddy is being severe problem due to the lower production and grain quality at ripening stage. This study was conducted to examine the effect of Iprobenfos-metconazole (IPM) treated 50, 40 and 30 days before heading respectively as a plant regulator to reduce the lodging at ripening stage of direct seeding rice cultivation. The culm length treated with IPM, especially the 4th culm internode, was shortened more than with untreated plot, and the most effective time was at 30 days before heading. At 20 days after heading the flag leaves colour showed more greening than in the untreated leaves and the plot with IPM treatment was to be maintained longer compared to the control plot. The Nitrogen concentration of leaves with IPM was lower than in the control plot, and $SiO_2$ contents were higher than in the untreated plot and $SiO_2/N$ ratio was increased more in the IPM plot than in the control plot. The breaking strength of 3rd and 4th culm internode with IPM treatment was higher than in the untreated plot, and the lodging index was reduced in the IPM plot significantly and the field lodging also was reduced. As the results the rice production in the IPM plot was increased more due to be higher ripening ratio and seed grain weight compared to the untreated plot to be occurred the field lodging.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.39.1-39
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• 1999

• Korean Journal of Veterinary Research
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• v.33 no.3
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• pp.455-460
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• 1993

In the present study, the effects of 4 agricultural chemicals commonly used in this conuntry were experimentally assessed on Lymnaea viridis the intermediate host of Fasciola hepatica, which in non-target organism of these chemicals. The major habitat of the snail is rice paddies in Korea and many agricultural chemicals are used for weed, fungi or insect control in rice paddies and there is a general concern that certain levels of these chemicals could reach the aquatic ecosystem and possible alter the snail life. Agricultural chemicals used in this study included two herbicides, an insecticide and a fungicide. The tenth generation of laboratory reared snails were selected and exposed to the varying concentrations(0-100 ppm) of these chemicals. As concentrations and time of exposure increase, the per cent mortality increases(p<0.01). $LC_{50}$(lethal concentration for 50% mortality) values of these chemicals on snail after 96-hour exposure were variable; iprobenfos showed the highest acute toxicity(12.6 ppm), while carbofuran showed the lowest acute toxicity(74.5ppm). Sublethal concentrations of chemicals after 96-hour exposure were also variable ; bentazone showed the highest chronic toxicity(0.81ppm), while carbofuran showed the lowest chronic toxicity(5.04 ppm).

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.236-246
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• 2014

Pesticide is used to protect the crops, but also become a cause of polluting the environment. Perform a risk assessment using physical and chemical properties, environmental fate and toxicity data in order to determine the pesticide registration. The aquatic model estimates pesticide concentrations in water bodies that result from pesticide applications to rice paddies and apple orchard. The used models are the PRZM, EXAMS and AGRO shell (PA5), Rice Water Quality Model (RICEWQ) and Screening Concentration In GROund Water (SCI-GROW). The residual concentration of water body was estimated using meteorological data, crop calendar and soil series of Korea. The chosen pesticides were butachlor, carbofuran, iprobenfos and tebuconazole. It has shown the potential that the RICEWQ is possible to predict residue level in water of butachlor and iprobenfos, because the maximum value in water monitoring data is lower than the peak concentration of the model, and the minimum value is lower than the average annual concentration of the model. But RICEWQ was insufficient to predict exposure concentrations in ground water. The estimated exposure concentrations of carbofuran in ground water is very higher than in surface water because of its low soil adsorption coefficient. Although tebuconazole were not detected in the water monitoring that means very low concentration, it is possible that the PA5 can be used to predict residue level in water.