• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.177-187
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• 2011

This study was performed to evaluate the polymers and surfactants as the potential control agents of sweet potato whitefly Bemisia tabaci, which is causing problems in ornamental garden and greenhouse. Polymers have an insecticidal activity to knock down and to be lethal to small winged insects by its viscosity. Among five polymers tested at 0.2% concentration, polinol P-24 showed the highest insecticidal activity as 59.4% against B. tabaci adult in cylindrical chamber, and followed by polinol P-20 (insecticidal activity, 57.1%). When treated at 0.1 % or 0.3% concentrations, Polinol P-24 also showed the highest insecticidal activity with 43.3% and 54.5%, respectively. Among eight surfactants tested, insecticidal activity was the highest in 0.0005% NP10 treatment (70.0%), and followed by 0.001% NP7 (67.4%). The synergistic effect between polinol P-24 and eight surfactants was evaluated. After bioassays, the 0.2% polinol P-24 plus 0.005% NP10 was selected as a candidate control agent for controlling of B. tabaci adults. Polinol P-24/NP10 was showed the highest control efficacy against B. tabaci adults applied three times at three day-intervals in square rearing cage. In the greenhouse, the mixture treatment showed good control value over 70% seven days after treatment.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.18-26
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• 2007

Fungicidal screening was performed to control soybean black root rot caused by Calonectria ilicicola through in vitro and greenhouse assays. In in vitro assay, 25 fungicides were assessed by an agar dilution method and a 96-well microtiter plate method. While protective fungicides including dithianon, dichlofluanid, mancozeb, and captan showed a very low activity against the mycelial growth C. ilicicola SC03-15 in the agar dilution method, they displayed potent inhibitory activity against spore germination in a 96-well microtiter plate method with $EC_{50}$ values of 4.65, 0.61, 4.64, and $0.29{\mu}g\;mL^{-1}$, respectively. Ergosterol biosynthesis-inhibiting (EBI) fungicides showed different antifungal activity against mycelial growth and spore germination according to molecules. Difenconazole displayed higher antifungal activity against spore germination rather than mycelial growth, and prochloraz inhibited potently both mycelial growth and spore germination with EC50 values less than $1.8{\mu}g\;ml^{-1}$. In contrast, the other EBI fungicides inhibited more highly mycelial growth than spore germination. Carbendazim+diethofencarb and dazomet also inhibited both mycelial growth and spore germination of C. ilicicola SC03-15 at very low concentrations. In greenhouse assay, carbendazim+diethofencarb effectively controlled a soybean black root rot by drenching 2 days before or after inoculation. In addition, tebuconazole showed potent curative activity against soybean black root rot.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.391-394
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• 2012

Exposure and risk assessment during mixing/loading of chlorpyrifos emulsifiable concentrate (EC, 20%) were carried out. Limit of detection and limit of quantitation were 0.02 and 0.1 ng, respectively. Calibration curve linearity and reproducibility were excellent. Recovery of chlorpyrifos from gloves was 72.3-103.4%. During mixing/loading procedure, average hand exposure amount of chlorpyrifos was 3.9 mg which is corresponding to 0.004% of total active ingredient in the prepared spray mixture. In calculation of MOS (Margin of Safety) for risk assessment, male Korean average body weight and AOEL (Acceptable Operator Exposure Level) were used. Nine events of mixing/loading procedure were assumed per day. And 75 percentile of 30 repetition (4.6 mg) was used as for the worst case. MOS was more than 1 for total repetition, indicating mixing/loading work was of least risk. However, MOS of individual repetition was examined, two cases were less than 1 suggesting careful work habit is essential in mixing/loading procedure.

• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.81-87
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• 2005

Ethaboxam[(RS)-N-(a-cyano-2-thenyl)-4-ethyl-2-(ethylamino)-1,3-thiazole-5-carboximide] is a novel fungicide with high level of activity against Oomycetes fungi. The control effects of ethaboxam technical and various ethaboxam formulations were investigated against P. brassicae, the causal agent of clubroot disease in Chinese cabbage. When ethaboxam was applied to infested soil, club formation caused by P. brassicae was strongly inhibited at 8.33 mg/L soil and $EC_{50}$ of ethaboxam was 2.65 mg/L soil. Five ethaboxam formulations [10% suspension concentrate (SC), 15% SC, 2% granule (GR), 5% GR, 25% wettable powder] and mixture formulation of ethaboxam and metalaxyl (3%+1% GR) exhibited good efficacy against the pathogen. 10% SC, 15% SC, and 2% GR formulations of ethaboxam showed better disease controlling efficacy on Chinese cabbage clubroot than the other formulations. The $EC_{50}$ values of 10% SC, 15% SC, and 2% GR formulations of ethaboxam were 3.72 mg AI/L soil, 1.1 mg AI/L soil, and 4.95 mg AI/L soil, respectively. Among them, soil drenching application by 15% SC formulation of ethaboxam exhibited the most in vivo antifungal activity on P. brassicae. These results indicate that ethaboxam has a high potential for the control of clubroot disease.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.168-176
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• 2008

Recently damage of rice bakanae disease disseminated by infected seeds increased in paddy field in Korea. For controlling rice bakanae disease, the efficacy of 17 fungicides was assessed by 5 kinds of bioassay, spore germination test (SGT), mycelial growth test, detection test on Komada's medium (KDT), pouch test (PT) and greenhouse test (GT). Among ergosterol biosynthesis inhibiting fungicides, prochloraz showed a high controlling activity in all the assay systems while the others showed very low activity except for $500\;{\mu}g/ml$ of hexaconazole in GT and $500\;{\mu}g/ml$ of triflumizole in KDT. Although benomyl and the mixture of benomyl and thiram showed a good activity at 100 and $500\;{\mu}g/ml$ in SGT and PT, respectively, in GT they did a middle activity. Trifloxystrobin and kresoxim-methyl included in strobilurins showed a good activity even at $20\;{\mu}g/ml$ in KDT as well as a middle activity in SGT. Also a high activity not only at $10\;{\mu}g/ml$ in SGT but also at $100\;{\mu}g/ml$ KDT was detected in thiram. The activity of fludioxonil was confirmed in SGT, KDT and PT. Based on these results, it is very important to determine a bioassay system, because the fungicidal activity against rice bakanae disease was fluctuated depending on a assay systems as well as the mechanism of fungicide.

• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.1-12
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• 2001

A competitive indirect enzyme-linked immunosorbent assay (ci ELISA) for the organophosphorus insecticide acephate, O,S-dimethyl acetylphosphoramidothioate, was developed using a polyclonal antibody. Three different haptens mimicking the analyze and containing hexanoic acid moiety as a linker were synthesized, and then conjugated with the carrier proteins bovine serum albumin and keyhole limpet hemocyanin by the N-hydroxysuccinimide active ester method. Polyclonal antibodies raised against hapten-KLH conjugates in rabbits and the hapten-BSA conjugates as coating antigens were screened and selected for the assay in the homologous and/or heterologous ELISA system. The effects of various assay conditions, including blocking reagents, detergent content, organic solvents, pH, and preincubation of tile mixture of the polyclonal antibody and the analyze on the sensitivity were evaluated. The $IC_{50}$ value of acephate of 110 ng/mL was obtained in an optimized heterologous system using hapten-3-BSA as a coating antigen and a polyclonal antibody 8377, showing the detection range of 10-1000 ng/mL and the lowest detection limit of 4 ng/mL. The cross-reactivities of the structurally related insecticides, including methamidophos were less than 0.02%. These results indicate that the ELISA could be a convenient and alternative tool for monitoring acephate residues in agricultural products and environmental samples.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.54-63
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• 2015

Streptomyces spp. isolated from turfgrass rhizosphere and tested for their response to large-patch control fungicides. The tested fungicides were actually used in golf course or turfgrass cultivation to prevent large-patch disease. Tolerance to 3 triazole group of the strains was the highest to the PR fungicide, and following the SR fungicide, whereas the isolated strains were no tolerance to HR fungicide. Tolerances to three kind of Strobilurin group were similar for the all of the tested Streptomyces spp.. Growth and sporulation of the all strain was normal in CB and AP fungicide treatments. However no spore formulated in double concentration. Strains, tolerance to acetanilide fungicides, appeared that KT fungicide tolerance was higher than MK fungicide. The selected strains showed strong tolerance against AT fungicide but have no tolerance to ATR fungicides. In conclusion, the bacterial strains showed tolerance against 1 carbamate, 1 organophosphate and 1 cyanopyrrole group, while have no tolerance against two mixture formulations (1 Quinone + Strobilurin and 1 Imidazole + Triazole).

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.22-27
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• 2011

Nonylphenols are toxic compounds classified as endocrine disruptors. We investigated the nonylphenols clean-up procedures for the contamination control in the quantitative analysis. In this research we analyzed the residual nonylphenols in the solvent and the SPE cartridges. First, at the analysis of HPLC grade solvents (n-hexane, diethyl ether, ethyl acetate and its mixture), diethyl ether was confirmed the residue as 0.963 ${\mu}g/mL$, and we eliminated the contaminant through the distillation with $CaH_2$, Second, at the analysis of SPE cartridges (silica gel and Florisil), all products were showed the residue at 0.046~13.0 ${\mu}g/mL$, but unfortunately the residue in the cartridge were not easily removed with referenced methods in all tested SPE cartridges except in silica gel SPE cartridge with glass ware.

• Journal of Sericultural and Entomological Science
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• v.28 no.1
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• pp.43-53
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• 1986

Among many microbial pesticides, Bacillus thuringiensis is one of the most hopeful pesticide and some commercial products have been appearing on the market. Because these commercial products contain living spores and toxins of the organism, there is a danger that living spores of B. thuringiensis may be scattered by wind and cause a great damage in the sericulture areas. In order to avoide these risks it is desirable to select the strain which has low pathogenicity to the silkworm, and at the sometime being highly pathogenic to the pest insects. Thus this study has been carried out to acquire some basic informations about the procedure of desicable strain selection. Three strains of B. thuringiensis var. kurstaki, var. dendrolimus and var. aizawai were used for the pathogenicity test on the silkworm, Bombux mori and the fall webwarm, Hyphantria cunea. Those strains were investigated by the agarose gel electrophoresis patterns of plasmid DNA determine whether mutation had occured. Pathogenicity tests were carried out of using isolated crystal proteins and spore-crystal protein to mixtures of each strain, seperatively. In case of using spore-crystal protein mixture, the order of pathogenicity in varities of B. thuringiensis against B.mopri and H.cunea were kurstaki, aizawai, dendrolimus and kurstaki, dendrolimus, aizawai, respectively. But using isolated crystal proteins, dendrolimus had the highest toxicity to H. cunea and the lowest toxicity to B. mori among tested three strains. From the above results, dendrolimus was presumed the most desirable straing for using microbial pesticide.

• Journal of Bio-Environment Control
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• v.21 no.2
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• pp.134-139
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• 2012

Inhibition effects on spore germination and mycelia growth for gray mold (Botrytis cinerea) were investigated in vitro using environment-friendly agricultural materials as well as environment-friendly pesticides. The inhibition effect on mycelia growth of gray mold is the highest when the gray mold mycelia were treated with a pesticide (commercial name: Koreayeok, Jihabudea KM, Sootingtan, Sootingstar) that contains a mixture of Bacillus subtilis, resulting in 100% inhibition of the mycelia growth. Meanwhile, the range of less than 20% inhibition effects on the growth of gray mold mycelia was observed with other commercial agricultural materials. The significant inhibition effects on spore germination of gray mold fungus were shown in vitro with two water dispersible pesticides containing sulfur [BTB (97.7%) and SulfurStar (92.3%)], respectively. These in vitro results of inhibiting of the spore germination and mycelia growth together cannot found. It remains to be determined whether the selected environment-friendly agricultural materials in effective control of gray mold in vitro can be used to control gray mold in field.