• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.237-242
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• 2005

This experiment was carried out to develop the fast and simple method for pesticide residue analysis by using solvent free solid injector (SFSI) and to validate the efficiency of the method developed for the residue analysis of the endocrine disruptor-like pesticides such as endosulfan, metribuzin, trifluralin and vinclozolin. The samples after freeze drying were sealed in glass capillary tubes and then introduced into the heated injector of gas chromatogaphy. The required pre-heating times were 1 min for endosulfan and trifluralin, 5 min for vinclozolin, and 10 min for metribuzin. The detection limits of endosulfan in chinese cabbages, metribuzin in lettuces, trifluralin in spinachs and vinclozolin in hot peppers were 0.05, 0.1, 0.05 and 0.05 ng, respectively and their recoveries were ranged from 74%, $98{\sim}107%$, $86{\sim}95%$ and $94{\sim}95%$, respectively. The detected level of metribuzine residue in field lettuce samples by using the SFSI was 0.6 ng/mg.

• The Korean Journal of Pesticide Science
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• v.18 no.2
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• pp.53-60
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• 2014

This study was conducted to investigate the changes of the residual amount in the leafstalk (end) and the fore-end (upper) portion of lettuce leaves during cultivation period to 14 days, 12 times in total (0, 1, 2, 3, 4, 5, 7, 8, 10, 12, 13 and 14 days) after spraying with boscalid and lufenuron. In the case of boscalid, the initial concentrations at 3 hours (0 day) of the leafstalk and the fore-end portion of lettuce leaves were 18.26 mg/kg and 84.97 mg/kg, respectively and the residual amounts were rapidly decreased to 0.31 mg/kg and 0.37 mg/kg at 14 days after chemical application. In the case of lufenuron, the initial concentrations at 3 hours (0 day) of the leafstalk and the fore-end portion of lettuce leaves were 0.91 mg/kg and 5.21 mg/kg, respectively and the residual amounts were rapidly decreased to 0.06 mg/kg and 0.09 mg/kg at 13 days after chemical application. The variations of the residual concentrations analyzing 12 times after spraying showed that the residual amounts of the leafstalk portion of lettuce leaves were less than its fore-end portion in boscalid and lufenuron. In additon, 9 kinds of pesticide including boscalid in 16 lettuce leaf (found to contain pesticide in 2013) showed that the residual amounts of the leafstalk portion of lettuce leaves were less than its fore-end portion as well.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.269-276
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• 2019

A colorimetric rapid detection method based on acetylcholinesterase (AChE) was developed for the analysis of organophosphorus (OP) and carbamate (CB) pesticides. The AChE catalyzes acetylthiocholine into thiocholine having (-) and (+) charges, and the (+) charge results in gold nanoparticle (GNP) aggregation. The in-activation of AChE by OP and CB has been well known. In order to optimize the colorimetric method, optimal dilution times of commercial serum containing AChE, diameter of GNP, and concentration of acetylthiocholine were tested as a key parameter. The colorimetric detection limits of the method were 7.5 ng/mL for both dimethyl amine and carbofuran pesticides in 60% ethanol. No cross-reaction to other chemicals, such as aflatoxin B1 and ochratoxin A, which can be contaminated with pesticides in agricultural products, was observed. Recoveries from lettuce, sesame leaf, and cabbage lettuce spiked with known concentrations of dimethyl amine and carbofuran were found to be ranged from 83.85 to 133.16%. These results indicated that the colorimetric rapid method based on AChE can be a useful tool for the sensitive, specific, rapid, and accurate detection of OP and CB pesticides in fresh vegetables.

• Korean Journal of Environmental Agriculture
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• v.5 no.2
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• pp.119-129
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• 1986

Disappearence of the trichlorfon (Dipterex) in the forest, following aerial to control Agelastica coerulea B., were studied by sampling deposits on slide glasses, soils, water, and leaves, and analysing with a gas chromatograph equipped with an electron capture detector. By analysing the amount remained on slide glasses, it was shown that the pesticide was adequately sprayed and nearly all deposit was lost in a day. The amount deposited under the tree was about 1/100 of the amount at an exposed site. Concentration of trichlorfon in creek water was 10 to 100 times as high as the acute toxic level to zooplankton for 6 to 24 hours, The rain could recontaminate the stream water up to the toxic level. Loss rate of trichlorfon from soils showed variations by sampling sites and was generally slower than from slide glasses. Amount deposited on leaves were less than the calculated or expected amount. The loss from leaves were similar to that from soil.

• Applied Biological Chemistry
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• v.47 no.1
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• pp.113-119
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• 2004

Persistence of the triazole fungicides, bitertanol and tebucnazole was investigated after their application at recommended and double rate on greenhouse-grown peppers. The half-life of bitertanol and tebuconazole on peppers at recommended and double rate was $5.2{\sim}6.1$ and $4.6{\sim}5.2$ days, respectively. Half-lives of bitertanol and tebuconazole on pepper leaves $(16.8{\sim}22.5\;days)$ was longer than those in the peppers. Residual concentration of bitertanol and tebuconazole on pepper leaves 24 days after application were 10.1 and 17.5 mg/kg, respectively, and these levels were higher than MRL which had been established at 3.0 and 5.0 mg/kg in Korea. Pattern of dissipation was well fitted to the first-order kinetics. In household washing experiment with surfactant, dislodgeable portions on pepper leaves of bitertanol and tebuconazole were occupied 36% and 48% of the residues found 24 days after application.

• The Korean Journal of Pesticide Science
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• v.12 no.1
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• pp.74-81
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• 2008

To elucidate the exposure of pesticide in agricultural environment and to investigate distribution of pesticide in paddy fields. This experiment was carried out to clarify pesticide distribution in paddy fields applied with different formulations and growing stages. Initial dissipation rate of applied butachlor EW and oxadiazon EC before rice planting were more than 90% within 3 days in paddy fields. The distribution of a.i. in the pesticide formulations tested depended upon the elapsed time at each growing stage of rice plant after application. Most of pesticides applied within 15 days after transplanting of rice seedlings, more than 95%, were located in the surface water and soil regardless of pesticides; butachlor, thiobencarb and molinate GR. The distribution of iprobenfos GR, tricyclazole WP and phenthoate EC, after application 2 hours in middle growing stage (46 days after rice planting) were shown as 16.1, 48.9 and 38.9% in surface water, 83.6, 15.4 and 10.7% in soil, and 0.3, 35.7 and 50.4% in rice plants of paddy fields, respectively. Also tricyclazole WP and phenthoate EC, after application 2 hours in the late rice growing stage (90 days after rice planting) were distributed to 7.8 and 9.8% in surface water, and 21.7 and 5.1% in soil, and 70.5 and 85.1% in rice plants of paddy fields, respectively.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.289-295
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• 1995

This study was carried out to develop a controlled-release insecticide formulation for the control of rose aphid (Macrosiphum ibarae) in rose and cotton aphid (Myzus persicae) in chrysanthemum (Dendranthema grandiflorum var. Meibung) in greenhouse. Imidacloprid[1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] was chosen as a toxicant. Two synthetic polymers, low density polyethylene(LDPE) and ethylene vinyl acetate(EVA), were used as polymer matrices. The tested plastic sheet formulations were prepared by heat-aided extrusion procedures after mixing imidacloprid technical and the polymers of three different combinations, and physicochemical properties as well as efficacy of the formulations were investigated. The amounts of imidacloprid recovered and incorporated in the formulations were recorded over 90% and 80%, respectively. Release of the active ingredient from the formulations was remarkably affected by mixing rates of polymers. The active ingredient in the formulations was chemically unstable with over 10% degradation rates after 90 day storage at $50{\pm}2^{\circ}C$. The residual amounts of imidacloprid in the soil treated with the formulations were paralleled with the release pattern of the formulations. Efficacy of the formulations on rose and cotton aphid was maintained over 90% even 120days after treatment under greenhouse.

• Korean journal of applied entomology
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• v.59 no.2
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• pp.145-152
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• 2020

The populations of Polyphagostarsonemus latus (Acari: Tarsonemidae) peaked two times on green perilla grown in greenhouses of Geumsan-Gun, Chungchungnamdo. The first peak of P. latus was in the middle of June, after it was first detected in late May. The population of P. latus peaked for the second time in mid July as its density stared rapidly increasing in early July. The application of chemical pesticides and eco-friendly agricultural materials, the two management methods used to control P. latus on green perilla, did not alter the occurrence patterns of P. latus; population size of the mite was much larger in greenhouses using chemical pesticides than in the ones using eco-friendly agricultural materials. This difference might be cuased by continuity of the management methods. Chemical control of P. latus should be limited owing to pesticide residue. The highest density of P. latus on green perilla plants was observed after 25 days after inoculation. The density was the highest in mid-aged leaves (e.g., the largest leaves) and the lowest in newly developed leaves (e.g., smallest leaves). However, there was no significant (P > 0.05) correlation between leaf size and density of P. latus. These results indicate that leaf size (e.g., leaf age) did not affect the occurrence of P. latus. Thus, any leaf of a green perilla plant is available as a sample unit for P. latus.

• The Korean Journal of Pesticide Science
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• v.11 no.2
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• pp.106-116
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• 2007

Pesticide, chlorfluazuron was subjected to determine the safety of terminal residues at the harvesting date of perilla leaves cultivated in plastic house. After the pesticide applied on a foliar spray in 2005 and 2006, leaf persistence of its residue was analysed for 10 days before leaf harvest. The degradation rate of chlorfluazuron in the leaf was 32.3 %(standard application), 43.6 %(double application) and 78.0 %(standard), 80.4 %(double) at second and tenth day, respectively, under analysis of GC/ECD in 2005. The degradation rate of chlorfluazuron in the leaf was 33.1 %(GC/ECD analyze), 34.0 %(HPLC/UVD analyze) and 77.9 %(GC/ECD), 78.4 %(HPLC/UVD) at second and tenth day, respectively, under the standard level of pesticide in 2006. The biological half-life of the chlorfluazuron residue was estimated by the regression equation calculated from daily dissipation of pesticide in the perilla leaves. The longest half-life of the chlorfluazuron residue in perilla leaves was 5.5 days. The maximum residual limit(MRL) for chlorfluazuron based on the longest half-life was estimated 2.0ppm at harvesting day, 2.5ppm at second day and 7.1ppm at tenth day before leaf harvesting of perilla.

• The Korean Journal of Pesticide Science
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• v.3 no.1
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• pp.57-65
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• 1999

The midge Chironomus riparius is a member of widespread dipteran insect which has been used for sediment toxicity test. The 2nd-3rd larvae Chironomus riparius were exposed to $^{14}C$-lambda-cyhalothrin in laboratory water only system(A) and sediment-water system(B) at $20{\pm}2^{\circ}C$. The concentration was nominally in the range of 0.16 to $20{\mu}g/{\ell}$ and 62.5 to 8000 ${\mu}g/kg$, respectively. System(A) was prepared by applying the chemical to 250 ml water and introducing Chironomus riparius larvae into the system(day 0). System(B) was prepared by applying the chemical to the 25 g of soil and 250 ml water and shaking and rolling them for two hours. After allowing the system to settle for two days, Chironomus riparius larvae were introduced into the system. After 72 hours, the two systems were terminated and dead larvae were observed. The measurement of residue in water was conducted at the start(day 0) and the end of the study(day 3). The residue of $^{14}C$-lambda-cyhalothrin in water was accounted for approximately 65% of nominal concentration in system(A) and $0.2{\sim}0.4%$ in system) on 3 days. $LC_{50}$ was less than $0.156{\mu}g/{\ell}$ in system(A) and 889 ${\mu}g/kg$ in system(B), based on the nominally applied concentration.