• Applied Biological Chemistry
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• v.44 no.2
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• pp.109-115
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• 2001

The foliar uptake of dimethomoiph induced by several nonionic surfactants was measured in order to study the correlations between the uptake rate of dimethomorph and the fungicidal activity to cucumber downy mildew. Dimethomorph was not absorbed in cucumber leaf in the absence of activator surfactant. And the curative effect of dimethomoiph WP to cucumber downy mildew was very low under the concentration of 250 ${\mu}g/ml$. But dimethomorph uptake was remarkably enhanced by addition of nonionic surfactants, such as polyoxyethylene cetyl ether, polyoxyethylene oleyl ether, and polyoxyethylene stearyl ether. And the curative effect to cucumber downy mildew was enhanced with proportion to uptake rate of dimethomorph. The protective effect to cucumber downy mildew, however, tends to decrease with the increase of foliar uptake of dimethomorph. The uptake rate of dimethomorph to cucumber leaf was proportional to the content of polyoxyethylene cetyl ether in formulation, but was decreased with dilution.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.127-133
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• 2008

The foliar uptake of dimethomorph into cucumber was assessed by spray application of aqueous dimethomorph solution containing fatty alcohol ethoxylate (FAE) or fatty acid alkyl ester as activator adjuvants. Afterward, the possible mechanism of action of FAE on foliar penetration of active ingredient was suggested by speculating on the effect of lipophile and hydrophile of FAEs. The amount of absorbed dimethomorph induced by polyoxyethylene mono-9-octadecenyl ether (6 moles ethylene oxide, $C_{18=9}E_6$) was linearly related to the concentrations of surfactant as well as dimethomorph in spray solution, suggesting that it is simply a diffusion phenomenon of the solute molecule through a cuticular membrane from leaf surface. Octadecanol attached to FAE was most effective lipophile on the leaf penetration of dimethomorph. And, the more ethylene oxide had the polyoxyethylene chain of FAE up to 20 moles, the higher the uptake rate was. Therefore, the role of lipophile of FAE on dimethomorph penetration to cucumber leaf, probably, is to modify the physico-chemical properties of cuticular membrane to be permeable to dimethomorph, and the polyoxyethylene chain having less than 20 moles ethylene oxide, which is moderately permeable to cuticular membrane by its molar volume, is to let the physically-modified cuticular membrane to be maintained for a longtime.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.118-126
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• 2008

In order to find the best compositions of the dimethomorph formulation containing fatty alcohol ethoxylate surfactants as an activator adjuvant and recommend the good management way of the formulations to allow an intended uptake rate, factors affecting foliar uptake of active ingredients into cucumber were investigated and compared each other. Among tested, the most important factors were air temperature in which plants were located after spraying of aqueous formulations containing activator adjuvant, and deposit of wax on the leaf surface of cucumber. Dimethomorph uptake was found to be increased by sunlight. When aqueous formulations had long-polyethoxylated fatty alcohol surfactants, the relative humidity of the room in which the plants were located after spraying with the formulations did not severely influence the foliar uptake. Maintaining a mild temperature and avoiding too strong sunlight after spraying with dimethomorph formulations were found to be resonable management strategies.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.117.1-117
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• 2003

Phytophthora blight, caused by P. capsici, is very important disease of pepper. Many fungicides to control of Phytophthora blight have been developed, but most of fungicides disappeared in short periods. Nowadays dimethomorph was known as one of the most effective to control of this disease. P. capsici isolates from pepper fields were collected and surveyed their growth in dimethomorph amended V8 medium in order to evaluate their fungicides resistance. The fungicide resistant isolates were not founded among them. Most of the sensitive isolates were inhibited perfectly in V8 medium amended with 10ppm dimethomorph. Mutants of P. capsici by dimethomorph, was grown very well in 250ppm. The difference of pathogenicity, colony morphology, drug response, RT-PCR results was identified between sensitive and resistance isolates. This study should be provided a basic information about the occurrence of dimethomorph resistant isolates and genetic changes in P. capsici population.

• The Korean Journal of Pesticide Science
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• v.6 no.4
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• pp.287-292
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• 2002

To establish effective and safe control method against Phytophthora root rot caused by Phytophthora capsici on tomato in hydroponic culture, three pesticides, oxadixyl copper hydroxide 8% WP, metalaxyl copper oxychloride 15% WP, and dimethomorph. dithianon 38% WP at 4 concentration levels were tested on potato dextrose agar medium inoculated with Phytophthora capsici. All pesticides inhibited mycelial growth, but two pesticides of them, metalaxyl copper oxychloride WP and dimethomorph. dithianon WP, were selected as effective pesticides for the efficacy test in a hydroponic culture. Forty days after transplanting of tomato seedlings, 4 ml of sporangia of P. capsici (about 25 sporangi/ml) per plot was inoculated around tomato plant root, and then 5 days after inoculation, the pesticides diluted at 5,000 times were drenched 1, 2 or 3 times per plot on the culture cube at 15 days interval. Fifteen days after drenching, tomato fruits and hydroponic culture solution were sampled for the analysis of pesticide residues. Dimethomorph was detected 0.001 and 0.003 mg/kg in tomato of the plots sprayed 2 and 3 times with dimethomorph dithianon WP of which detection levels were far below compared with 1.0 mg/kg of the Korean MRL of dimethomorph on tomato. Incidences of Phytophthora root rot were $30.5{\sim}50%$ in the plots drenched at 1 or 2 times with metalaxyl.copper oxychloride WP, and $16.7{\sim}25%$ in the plots treated with dimethomorph dithianon WP. However, there was no incidence of Phytophthora root rot in the plots treated at 3 times with both of pesticides, showing no phytotoxic effect. Based on the results, the drenching of these pesticides on the culture cube could be recommended as a very safe and effective control method for Phytophthora root rot in tomato.

• The Korean Journal of Pesticide Science
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• v.7 no.4
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• pp.264-270
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• 2003

To control effectively and safely Phytophthora root rot caused by Phytophthora capsici on tomato in hydroponic culture, tank-mixing method was considered with two pesticides, metalaxyl copper oxychloride 50% WP and dimethomorph dithianon 38% WP. Forty days after transplanting of tomato seedlings, 4 mL of sporangia of P. capsici (about 25 sporangi/mL) per plot was inoculated around tomato plant roots, and at 5 days after inoculation, the pesticides tank-mixed at three dilution levels, 12,500, 25,000 and 50,000, were drenched 1, 2 or 3 times per plot on the culture cube every 15 days for metalaxyl copper oxychloride 50% WP and every 10 days for dimethomorph dithianon 38% WP. During the drenching period, the residue levels of metalaxyl and dimethomorph in hydroponic culture solution were similar to the initial levels but the level of dithianon was drastically decreased from one day after tank-mixing. In tomato drenched with metalaxyl copper oxychloride 50% WP, metalaxyl was detected $0.02\sim0.04$ mg/kg in all diluted plots. Dimethomorph was detected $0.012\sim0.021$, $0.001\sim0.006$ and $0.001\sim0.003$ mg/kg in 12,500, 25,000 and 50,000 times diluted plots, respectively, while dithianon was detected 0.005, 0.003 mg/kg in 12,500 and 50,000 times diluted plots, respectively. The detection levels of three pesticides were far below compared with the levels of Korean MRLs. Incidences of Phytophthora root rot were not found in all the plots, but phytotoxic responses were recognized in the 12,500 times diluted plots of both pesticides. Based on the above results, the drenching of the culture solution tank-mixed with these pesticides could be recommended as a very safe and effective method to control Phytophthora root rot in tomato in hydroponic culture.

• 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.

• Research in Plant Disease
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• v.20 no.1
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• pp.25-30
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• 2014

Phytophthora infestans was isolated from potato leaves collected from main potato producing areas in Korea during 2009-2011. In 2009, 99 isolates tested were all A1 mating type. Two of 64 isolates in 2010 and two of 78 isolates in 2011 were A2 mating type and they were found only in Miryang area. Among 99 isolates examined in 2009, 13.1% was resistant to metalaxyl, 3.1% was intermediate resistant and 83.8% was sensitive. In 2010, 19.4% of 62 isolates was resistant, 4.8% was intermediate and 75.8% was sensitive. Metalaxyl resistant, intermediate and sensitive isolates collected in 2011 were 23.1%, 9.0% and 67.9%, respectively. Metalaxyl resistant isolates increased mainly in winter cropping areas and seed potato producing areas where fungicides were sprayed more often. Frequencies of isolates showing minimum inhibition concentration of dimethomorph at $1.0-5.0{\mu}g/ml$ were 17.2% in 2009, 19.0% in 2010 and 15.4% in 2011. However, there was no evidence for occurrence of resistant isolate to dimethomorph because no isolate was able to grow at $5.0{\mu}g/ml$.

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.199-208
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• 2007

Three pesticides commonly used in perilla leaf were subjected to a field residue trial to ensure safety of terminal residues in the harvest. The residual patterns of three pesticides, which were dimethomorph, indoxacarb and procymidone were examined after applying with the recommended and double dose and their DT50 were calculated. Also degradation patterns of pesticides at storage $4^{\circ}C$ were compared to those at $20^{\circ}C$, and removal rates of pesticides by washing perilla leaf with water were measured. Biological half-lives of dimethomorph, indoxacarb and procymidone were $2.91{\sim}3.11,\;2.53{\sim}3.14\;and\;2.62{\sim}2.92$ days, respectively. During the storage period, the degradation patterns were appeared more obviously at $20^{\circ}C$ than $4^{\circ}C$. Removal rates of dimethomorph, indoxacarb and procymidone were $51.3{\sim}73.3%,\;74.1{\sim}91.3%\;and\;57.9{\sim}81.6%$by various washing methods.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.456-462
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• 2010

Baseline sensitivity to benthiavalicarb, iprovalicarb and dimethomorph included into carboxylic acid amide (CAA) group was evaluated in 180 isolates of Phytophthora capsici over 4 years from 2005 to 2008. $EC_{50}$ (effective concentration inhibiting mycelial growth by 50%) value of benthiavalicarb ranged from $0.015{\mu}g\;mL^{-1}$ to $0.049{\mu}g\;mL^{-1}$ with a mean of $0.033{\mu}g\;mL^{-1}$. The mean values of $EC_{50}$ of iprovalicarb and dimethomorph were 0.411 (0.197 - 0.556) ${\mu}g\;mL^{-1}$ and 0.271 (0.101 - 0.798) ${\mu}g\;mL^{-1}$, respectively. Although there was no increasing tendency in $EC_{50}$of benthiavalicarb and iprovalicarb during 4 years, $EC_{50}$ of dimethomorph was increased gradually by laps of time. There was no cross-resistance between each fungicide used in this study and metalaxyl. Among fungicides included into CAA group, there was a positive correlation between benthiavalicarb and iprovalicarb, and between dimethomorp and mandipropamid.