• Korean Journal of Environmental Agriculture
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• v.15 no.1
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• pp.105-115
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• 1996

In this paper, we reviewed the degradation factors of diazinon which was known to be easily degraded by soil microorganisms and lost of its activity. Under submerged soil condition, the contribution of microorganisms to diazinon degradation was about 40% and these microorganisms preferred soil humus as substrates to diazinon itself. The effect of monooxygenase activity in submerged soil was more important than esterase activity on diazinon degradation and these enzymes were inhibited by several chemicals such as piperonyl butoxide(PBO), EPN and tricyclazole. From these results, new formulation type of diazinon (PBO and triphenyl phosphate were added to commercial diazinon formulation by 0.1% respectively.) and diazinon mixture formulation (diazinon was mixed with EPN, tricyclazole and carbofuran in equal amount) were prepared. The new formulation type of diazinon showed better insecticidal activity by 12% and more delayed diazinon degradation in ten days than commercial diazinon.

• The Plant Pathology Journal
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• v.16 no.3
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• pp.125-129
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• 2000

A rapid and efficient assay to determine melanin biosynthesis inhibition of Magnaporthe grisea, a causal agent of the rice blast, by chemicals was developed. Wells in 24-well plates were loaded with spore suspension of the fungus and three known melanin biosynthesis inhibitors of KC10017, tricyclazole, and carpropamid. Subsequent color changes of mycelia and culture media in the wells were observed 7 days after incubation. The wells treated with KC10017 (an inhibitor of polyketide synthesis step and/or pentaketide cyclization step) became colorless, whereas tricyclazole (an inhibitor of 1, 3, 8-trihydroxynaphthalene reductase) or carpropamid (an inhibitor of scytalone dehydratase)-treated wells exhibited red color. They did not show any inhibitory effect on fungal growth. The inhibition of reaction steps prior to 1, 3, 6, 8-tetrahydroxynaphthalene formation was easily determined by colorless medium and mycelia. However, it was impossible to distinguish between inhibition of reduction steps and inhibition of dehydration steps by colors of the cultures. It was accomplished through HPLC analysis of the melanin biosynthesis-involving pentaketide metabolites accumulated by the inhibitors. Through screening of a number of synthetic chemicals using the in vitro assay, we could find a novel chemical group of melanin biosynthesis inhibitor.

• Korean Journal of Environmental Agriculture
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• v.11 no.1
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• pp.1-8
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• 1992

New formulation of diazinon as granule preparing with piperonyl butoxide(PBO) and triphenyl phosphate(TPP) known as the inhibitor of monooxygenase(mo) and esterase was tested with the mortality of rice leaf hopper. Also, the mixed formulation of diazinon with tricyclazole, carbofuran and EPN were investigated about the residual pattern of diazinon in submerged soil condition at $30{\pm}2^{\circ}C$. Although the mortality about rice leaf hopper was higher only 10% on new formulation of diazinon than commercial at recommended dose but was 30-60% at half dose. Half life of diazinon in the formulation with 0.1% of PBO+TPP was 4.53 days in sterilized soil and 2.33 days in non-sterilized soil, and it was delayed about 0.74 and 0.45 respectively in contrast with the commercial granule. Also, half life of the new formulation with 1% PBO and PBO+TPP was delayed 0.44(PBO) and 0.65day(PBO+TPP) in non-sterilized soil condition, respectively. Half life of mixed formulation with tricyclazole, carbofuran, EPN or EPN+Carbofuran was delayed 2.61, 1.04, 0.43 or 2.7 days, respectively. As a result, the persistence rate of new formulation and mixed formulation was increased by inhibition of two enzymes affecting to the dgradation of diazinon in submerged soil.

• 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.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.337-342
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• 1991

A bacterium producing the antifungal compound KRF-001 isolated from soil was selected and identified as Bacillus subtilis. The antibiotic KRF-001 was active against various fungi. Effecacy of KRF-001 at various concentration for controlling leaf blast of rice in the paddy field was evaluated and compared with recommended rates of kasugamycin, blasticidin- s and tricyclazole. KRF-001 caused no irritation on the skin of rabbits and LD50 for mice was deduced more than 5000 mg/kg which indicates the possibility of low toxicity or no toxicity.

• Research in Plant Disease
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• v.26 no.1
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• pp.38-43
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• 2020

The genome of the rice blast fungus Magnaporthe oryzae contains several types of transposable elements (TEs), and some TEs cause genetic variation that allows M. oryzae to evade host detection. We studied how five abundant TEs in rice pathogens, Pot3, Pot2, MAGGY, Line-like element (MGL) and Mg-SINE, are expressed under diverse conditions related to growth, development, and stress. Expression of Pot3 and Pot2 was activated in germinated conidia and mycelia treated with tricyclazole. Retrotransposon MAGGY was highly expressed in appressoria and tricyclazole-treated mycelia. MAGGY and Pot2 were also activated during the early and late stages of perithecia development. MGL was up-regulated in conidia and during conidial germination but not during appressorium formation. No noticeable expression of Mg-SINE was observed under most conditions. Our results should help investigate if and how condition-specific expressions of some TEs contribute to the biology and evolution of M. oryzae.

• Research in Plant Disease
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• v.8 no.1
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• pp.50-54
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• 2002

A total of 55 Colletotrichum isolates from strawberry plants with anthracnose symptoms(crown rot) were inhibited in mycelial growth on potato-dextrose agar(PDA) amended with fungicides in variable degrees depending on the chemicals used, especially showing no growth on PDA with 1 mg/m/tricyclazole. However, in the detached leaf test by treating chemicals before or after inoculation of Colletotrichum sp., tricyclazole was little effective in controlling symptom development; instead azoxystrobin, which had low in vitro inhibition of mycelial growth, inhibited strongly the symptom development. Some chemicals were tested for the control of strawberry crown rot in greenhouse using three methods, sprays soil drenching and plant dipping. No or little control effect were made by chemical spray and soil drenching, but plant dipping in chemical solution, especially azoxystrobin: reduced crown rot development by about 50% in the greenhouse suggesting that the azoxystrobin treatment may be an effective control method of the crown rot of strawberry. No differences in the control efficacy were noted according to the dipping time and chemical concentration of azoxystrobin not less than 10 min and 250 mg/m/, respectively.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.273-281
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• 2012

This study was conducted for the establishment of the analytical method of pesticide residues in rice straw for 9 pesticides; etofenprox, tricyclazole, diazinon, edifenphos, propiconazole, carbaryl, carbofuran, 3-hydroxy carbofuran and 3-keto carbofuran and for the monitoring of these pesticides in rice straw for livestock feed in Korea. These pesticides were classified into 4 groups according to analytical instrument condition. Group 1 (HPLC-UVD1) included tricyclazole and etofenprox while group 2 (HPLC-UVD2) included propiconazole and edifenphos. Group 3 (HPLC-FLD) included carbaryl, carbofuran, 3-hydroxy carbofuran and 3-keto carbofuran. Group 4 (GC-NPD) included Diazinon. The dried rice straw samples were extracted with acetone and purified by liquid-liquid partition and solid phase extraction (SPE): Combination of Florisil SPE and amino-propyl SPE was used for group 1 and group 2, amino-propyl SPE for group 3, and Florisil SPE was for group 4. Recovery was in the ranged 70~110% and the limits of quantitation (LOQ) were lower than the half of maximum residue limits. Therefore this method was proved to be efficient for monitoring of these pesticides residue in rice straw. A total of 18 rice straw samples from 6 provinces in Korea in 2010 were analyzed using established method and, only 3-keto carbofuran was detected in one sample at concentration of 0.04 mg/kg.

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.403-413
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• 2008

This study was conducted to select excellent tank mix combinations of pesticides for aerial application by manned helicopter. Among 209 pesticide combinations of 3-way tank-mixing for aerial application, a total of 93 recommendable combinations including tricyclazole SC+validamycin-A SL+imidacloprid SL were finally selected for the simultaneous control of key pests on paddy rice such as blast, sheath blight, brown planthopper and moth. The selected combinations were not phytotoxic to rice plants and nearby non-target crops, and excellent in physicochemical properties of ultra low volume (ULV) spray solutions. The efficacies on sheath blight, brown planthoppers and white-backed planthoppers of pesticides sprayed by aerial application were similar to those of pesticides by conventional spraying. Total cost of aerial application in paddy rice was very economical as one fourth level of that of conventional spraying.

• The Plant Pathology Journal
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• v.17 no.4
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• pp.210-215
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• 2001

The phenotype of Rhizoctonia solani KR-13 was randomly segregated to both melanin-producing (M+) and non-producing (M-) types through successive cultures on PDA. M+type with dark melanin showed strong pathogenicity to rice and self-anastomosis. Meanwhile, M- type with white or less-melanized mycelia showed very weak pathogenicity and non-self-anastomosis. Melanin production of R. solani was affected by incubation temperature in both M+ and M- types, but not by light treatment. The application of tricyclazole, an inhibitor of fungal melanin biosynthesis, showed no controlling effect on R. solani causing rice sheath blight. Results of this study showed that melanization of mycelia of R. solani is an important pathogenicity factor in rice.