• The Korean Journal of Pesticide Science
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• v.17 no.3
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• pp.185-192
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• 2013

This study was performed to evaluate the spray toxicity and leaf residual toxicity of 52 kinds of insecticides registered for strawberry against adult honeybee Apis mellifera. According to the IOBC standard, the acute toxicity by spraying showed below 30% was classified as non-toxic. Among tested insecticides, 32 insecticides (flonicamid, lufenuron, novaluron, three kinds of acetamiprid, thiacloprid, milbemectin, acequinocyl, TBI-1, two kinds of chlorfenapyr, chlorfluazuron, cyenopyrafen, cyfumetofen, etoxazole, fenpyroximate, flubendiamide, flufenoxuron, hexythiazox, metaflumizone, two kinds of methoxyfenozide, DBB-2032, pyridalyl, spiromesifen, tebufenpyrad, teflubenzuron, acetamiprid + methoxyfenozide, acrinathrin + spiromesifen, bifenazate + spiromesifen, cyenopyrafen + flufenoxuron) did not show any toxic effect, it is thought to be safe. And the others (20 insecticides) showed higher toxicity to honeybee. Insecticides which showed acute toxicity higher than 90% was selected and tested the residual toxicity. All insecticides except emamectin benzoate EC, and indoxacarb SC showed 100% mortality at one day after treatment (DAT). However, the toxicities of emamectin benzoate, indoxacarb SC, and abamectin did not show until 3, 7, 14 DAT, respectively. Nine insecticides such as indoxacarb WP, thiamethoxam WG, abamectin + chlorantraniliprole SC, acetamiprid + etofenprox WP, acetamiprid + indoxacarb WP, bifenthrin + clothianidin SC, bifenthrin + imidacloprid WP, bifenazate + pyridaben SC, chlorfenapyr + clothianidin SC showed over 90% residual toxicity until 31 Day. In pouring treatment, thiamethoxam WG showed 76.9% mortality at 28 DAT and 50.0% mortality at 31 DAT. After 35 days, thiamethoxam WG showed no effect to honeybee. Bifenthrin + clothianidin SC and tefluthrin + thiamethoxam GR showed 57.1 and 80.0% mortality at 24 DAT, respectively. In spraying treatment, thiamethoxam WG and bifenthrin+clothianidin SC showed very high residual toxicity with 100% mortality in thirty-five DAT. After spraying treatment with thiamethoxam WG, bifenthrin+clothianidin SC, bifenthrin + imidacloprid WP, thiamethoxam WG showed 100% residual toxicity until 21 DAT and there was no activity after 28 DAT. Bifenthrin+clothianidin SC and bifenthrin+imidacloprid WP showed very high residual toxicity until 49 DAT.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.244-248
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• 2013

This study was carried out to investigate the residual characteristics and calculate processing factor of the environment friendly material matrine in fresh chilli pepper by drying. Spray solution of matrine was prepared by dilution of the commercial product (2% active ingredient) with water at 1 : 1000 (v/v) ratio and sprayed onto chilli pepper plants at seven day intervals. Samples were collected at 0, 1, 3, 5 and 7 days after last application and then dried using a hot air dry oven at $60^{\circ}C$ for 36 hours until the water content was reduced to 14%. Recoveries and storage period stabilities of matrine in the samples ranged from 106.6 to 119.1% and 106.6 to 113.1%, respectively. The residual concentrations of matrine in fresh chilli pepper and dried chilli peppers treated only once were found to be from less than 0.01 to 0.11 and from 0.03 to 0.25 mg/kg, respectively. In case of plants sprayed twice with matrine, the residual concentrations ranged from 0.02 to 0.12 and from 0.04 to 0.4 mg/kg, respectively. Processing factor of matrine in the fresh chilli pepper by drying was found to be from 1.5 to 3.3, indicating that the residual concentration of matrine in dried chilli pepper increased about two or three times by drying.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.95-103
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• 2010

Fomesafen is a selective herbicide, and used to control annual and perennial broad-leaf grass on soybean and fruit fields in USA and China, but not introduced in Korea yet. So, MRL (Maximum Residue Level), and analytical method of fomesafen were not establishment in Korea. Therefore, this experiment was conducted to establish a determination method for fomesafen residue in crops using HPLC-UVD/MS. Fomesafen residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover fomesafen from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The fomesafen was quantitated by HPLC with UVD, using a Shiseido CAPCELL-PAK UG C18 column. The crops were fortified with fomesafen at 3 levels per crop. Mean recovery ratio were ranged from 87.5% for a 0.4 ppm in hulled rice to 102.5% for a 0.4 ppm in apple. The coefficients of variation were ranged from 0.6% for a 2.0 ppm in hulled rice to 7.7% for a 0.04 ppm in green pepper. Quantitative limit of fomesafen was 0.04 mg/kg in representative 5 crop samples. A LC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fomesafen in agricultural commodities.

• The Korean Journal of Pesticide Science
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• v.3 no.3
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• pp.20-26
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• 1999

This study was to investigate the potential degradation of a herbicide paraquat by Fenton reagents(ferric ion and hydrogen peroxide) under UV light irradiation(365 nm) in an aqueous solution. When $10{\sim}500$ mg/L of paraquat was reacted with either ferric ion or hydrogen peroxide in the dark or under UV light, no degradation was occurred. However, the simultaneous application of both ferric ion(0.8 mM) and hydrogen peroxide(0.140 M) in paraquat solution(500 mg/L) caused dramatic degradation of paraquat both in the dark (approximately 78%) and under UV light(approximately 90%). The reaction approached an equilibrium state in 10 hours. In the dark, when $0.2{\sim}0.8$ mM ferric ion was added, $20{\sim}70%$ paraquat of $10{\sim}500$ mg/L was degraded, regardless of hydrogen peroxide concentrations($0.035{\sim}0.140$ M), while under UV light, 95% of 10 and 100 mg/L paraquat was degraded regardless of ferric ion and hydrogen peroxide concentrations. At paraquat concentration of 200 and 500 mg/L, paraquat degradation increased with increasing ferric ion concentrations as in the dark. However the increase in hydrogen peroxide concentration did not affect the extent of paraquat degradation. The initial reaction rate constants(k) for paraquat degradation ranged from 0.0004 to 0.0314, and 0.0023 to 0.0367 in the dark and under UV light, respectively. The initial reaction rate constant increased in proportion to the increase in ferric ion concentration in both conditions. The half-lives of paraquat degradation(t1/2) were 20 - 1,980 and 19 - 303 minutes in the dark and under UV light, respectively. This study indicates that Fenton reagents under UV light irradiation are more potent than in the dark in terms of herbicide paraquat degradation in an aqueous solution.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.328-335
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• 2012

In order to use in the classification of minor crop for the mutual application of safe use guideline, it was investigated the residue property of fungicide dimethomorph and pyraclostrobin in green onion, a stem-crop. After pesticides were applied 2 times with 1 week interval in that day of harvest, 3 days, 7 days, 10 days and 14 days before harvest, a green onion was harvested. The residue of dimethomorph in a green onion was 26.31 and 39.08 mg/kg in that day of harvest, however, in according to elapse time, it was reduced to 6.86 and 9.34 mg/kg in 14 days before harvest. In case of pyraclostrobin, it was also reduced from 13.46 and 39.08 mg/kg to 3.57 and 5.21 mg/kg. Based on the residue in that day of harvest, the deposit of spray solution in a green onion was calculated. The deposit of spray solution of dimethomorph was 274.35~345.84 mL/kg, in case of pyraclostrobin, it was calculated 213.65~343.33 mL/kg. When the amount of the deposit of both pesticides was compared in a green onion, it was so similar. On the other hand, it was estimated the predicted dissipation curve of pesticides in the green onion during cultivation. The half-life of dimethomorph was 6.95~7.45 days, in case of pyraclostrobin, 7.15~7.45 days. When both pesticides were compared with the residue property, the deposit of spray solution and half-life of dissipation were so similar.

• The Korean Journal of Pesticide Science
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• v.16 no.2
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• pp.98-108
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• 2012

In order to use in the classification of minor crop for the mutual application of safe use guideline, it was investigated the residue property of fungicide boscalid and fludioxonil at the same time harvest leafy-vegetables, such as spinach, ulgaribaechu, vitaminchae and cheongkyungchae. After pesticides were applied 2 times with 1 week interval in that day of harvest, 2 days, 5 days and 7 days before harvest, vegetables were harvested, and the residue of pesticides was investigated. Base on the residue in that day of harvest, the deposit of spray solution in vegetables was calculated. The deposit of spray solution of boscalid was 253.9 mL/kg in spinach, 83.0 mL/kg in ulgaribaechu, 97.8 mL/kg in vitaminchae, and 88.3 mL/kg in cheongkyungchae, respectively. In case of fludioxonil, it was calculated 157.6 mL/kg in spinach, 67.6 mL/kg in ulgaribaechu, 64.8 mL/kg in vitaminchae, and 66.6 mL/kg in cheongkyungchae, respectively. When the amount of the deposit of both pesticides was compared in leafy-vegetables, it was the highest in the spinach. On the other hand, it was estimated the predicted dissipation curve of pesticides in leafy-vegetables during cultivation. The half-life of boscalid was 5.9 days in spinach, 7.4 days in ulgaribaechu, 4.6 days in vitaminchae, and 4.3 days in cheongkyungchae, respectively. Also, it was estimated half-life in fludioxonil, it was 3.0 days in spinach, 4.0 days in ulgaribaechu, 3.2 days in vitaminchae, and 3.5 days in cheongkyungchae, respectively. The half-life was the longest in the ulgaribaechu. When both pesticides were compared with the residue property, the deposit of spray solution and half-life of dissipation of boscalid were more than those of fludioxonil.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.294-301
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• 2012

In order to use in the classification of minor crop for the mutual application of safe use guideline, it was compared a green onion with a scallion on the residue property of insecticide bifenthrin and chlorfenapyr. After pesticides were applied 2 times with 1 week interval in that day of harvest, 3 days, 7 days, 10 days and 14 days before harvest, vegetables were harvested, and the residue of pesticides was investigated. Base on the residue in that day of harvest, the deposit of spray solution in vegetables was calculated. The deposit of spray solution of bifenthrin was 123.0 mL/kg in a green onion, and 74 mL/kg in a scallion. In case of chlorfenapyr, it was calculated 126.5 mL/kg in a green onion, and 70.0 mL/kg in a scallion. When the amount of the deposit of both pesticides was compared a green onion with a scallion, it was higher in a green onion. On the other hand, it was estimated the predicted dissipation curve of pesticides in a green onion and a scallion during cultivation. The dissipation curve of bifenthrin was y = 1.0334 $e^{-0.0602x}$ ($R^2$= 0.8606) in a green onion, and y = 0.7693 $e^{-0.1823x}$ ($R^2$= 0.9756) in a scallion. In case of chlorfenapyr, it was y = 2.2603 $e^{-0.0519x}$ ($R^2$= 0.9043) in a green onion, and y = 1.2940 $e^{-0.1051x}$ ($R^2$ = 0.9782) in a scallion. The half-life of bifenthrin was 11.51 days in a green onion, and 3.80 days in a scallion, respectively. Also, it was estimated half-life in chlorfenapyr, it was 13.35 days in a green onion, and 6.59 days in a scallion, respectively. The half-life of both pesticides in a green onion was longer than in a scallion. When both vegetables were compared with the residue property, the deposit of spray solution and half-life of dissipation in a green onion were more than those in a scallion.

• The Korean Journal of Pesticide Science
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• v.8 no.3
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• pp.198-209
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• 2004

In order to elucidate the behavior of the fungicide hexaconazole in soil and rice plants, rice plants were grown for 42 days in a microecosystem (pot) containing fresh and 28 day-aged soil residues of $[^{14}C]$hexaconazole. The amount of $^{14}CO_2$ evolved during 28 days of aging was 0.11 % of total $^{14}C$-radioactivity treated and the averaged weekly degradation rate was 0.03%. Mineralization rates for 42 days of rice cultivation on fresh and aged paddy soils were 0.67% of the total $^{14}C$ in case of non-rice planting on aged soil and 1.17% in case of rice planting on aged soil, whereas 1.25% in non-rice planting on fresh soil and 1.72% in case of rice planting on fresh soil, suggesting that the amounts of $^{14}CO_2$ were evolved higher from fresh soils than aged ones and from rice-planting soils than non-planting ones. The amounts of volatiles collected were very low as background levels. Most of $^{14}C$-Radioactivity was remained in soil after 42 days of rice cultivation and $^{14}C$ absorbed through rice roots was distributed more in shoots than roots and translocated into the edge of shoots of rice plants. Amounts of non-extractable $^{14}C$ in soils were higher in rice planted soil than in non-planting soil. The distribution of non-extractable $^{14}C$ was increased in the order of humin>fulvic acid>humic acid. The amounts of $^{14}C$ translocated into rotational crop Chinese cabbage were 2.36 and 3.69% of the total $^{14}C$ in case of rice planted soil containing fresh and aged residues, respectively, suggesting that small amounts of $[^{14}C]$hexaconazole and its metabolite(s) were absorbed and their bound residues were more available than their fresh ones to Chinese cabbage.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.37-44
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• 2001

The biological effects of the iminoctadine tris (albesilate) and kresoxim-methyl for the protection of citrus postharvest diseases caused by penicillium spp. were assayed. In vitro tests, $EC_{50}$ values of iminoctadine tris(albesilate) were $0.01{\sim}0.02\;and\;0.01{\mu}g$ a.i./mL against mycelial growth of P. italicum and P. digitatum, respectively, but iminoctadine tris(albesilate) at $0.64{\mu}g$ a.i. /mL inhibited a little mycelial growth of unknown Penicillium sp. which produced another symptom different to blue and green mold caused by P. italicum and P. digitatum, respectively. And against germination and growth of germ tube of P. italicum and P. digitatum, $EC_{50}$ value of iminoctadine tris(albesilate) was $0.0013{\sim}0.0025{\mu}g$ a.i./mL. But spore germination of unknown Penicillium spp. was not nearly inhibited at $0.2{\mu}g$ a.i./mL. $EC_{50}$ values of kresoxim-methyl were $0.08{\sim}0.16$, 0.04 and $0.16{\mu}g$ a.i./mL against mycelial growth of P. italicum, P. digitatum and unknown Penicillium sp., respectively, and $0.04{\sim}0.08{\mu}g$ a.i./mL and $0.01{\sim}0.02{\mu}g$ a.i./mL against germination and growth of germ tube of P. italicum and unknown Penicillium sp., and P. digitatum, respectively. Iminoctadine tris(albesilate) and kresoxim-methyl were markedly effective to control the postharvest disease by 7 days spray prior to harvest. When the fruits were sprayed with iminoctadine-tris(albesilate) ($200{\mu}g$ a.i./mL) and kresoxim-methyl ($155{\mu}g$ a.i./mL) 7 days prior to harvest and subsequently stored for 90 days, the percentage of diseased fruit by Penicillium spp. was $3.6{\pm}1.8%$ in treatment of kresoxim-methyl and $5.9{\pm}1.8%$ in iminoctadine-tris(albesilate), respectively. On the other hand, tile percentage of diseased fruit was relatively high, $20.3{\pm}10.0%\;and\;19.5{\pm}9.6%$ in thiophanate-methyl ($700{\mu}g$ a.i./mL) and non-treatment, respectively. Maximum residue amount (ppm) among fruits (flesh and peel) assayed 0, 30, 60 and 90 days after storage was 0.45 and 0.10 ppm in treatment of kresoxim-methyl and iminoctadine, respectively.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.45-50
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• 2001

In recent, non virus-induced mosaic symptoms(NVMS) on potato leaves were observed in the seed potato fields, and its incidence rate was $5{\sim}20%$ nationwide. It made difficult to rogue out virus-infected plants, and caused much arguments between seed potato production farmers and seed potato inspectors. The objectives of these experiments were to find out the causes of NVMS, and also to induce mosaic symptom(phytotoxicity) on potato plants by treatment of several herbicides. No significant correlations were found between incidence rates of NVMS and values from soil analyses; soil pH, soil EC, organic matter content, and contents of inorganic constituents($P_2O_5,\;NO_3$, Ca, Mg, K) in the soil around the potato planted. The examinations by ELISA, virus indicator plants, and TEM showed that NVMS on potato leaves was not caused by the viruses infection. But, the use of herbicides could induced the NVMS on potato leaves. The incidence rates of potato treated with pendimethalin linuron of 400 mL/10 a, pendimethalin of 200 mL/10 a, pendimethalin.oxadiazon of 300 mL/10 a, and control were 61.1%, 47.2%, 19.4%, and 1.4%, respectively. Based on these results, we confirmed that the treatment of pendimethalin alone and in mixture with other herbicides were the reason of NVMS on potato leaves. The yields among test plots were similar except dicamba treated plot, which decreased by about 23% compared to control plot. When their progenies harvested in 1999 were planted in the following season, no symptoms of mosaic were observed.