• Korean Journal of Environmental Agriculture
• /
• v.11 no.2
• /
• pp.125-132
• /
• 1992

This study was conducted to know degradation products of the synthetic pyrethroid insecticide bifenthrin under soil, aqueous solution and UV-light irradation, and know its movement by leaching in soil. The major degradation product of bifenthrin was identified with 2-methylbiphenyl -3-y1 methanol by HPLC, UV, Mass and NMR under soil, aqueous solution and UV-light irradiation, The main degradation route was hydrolysis of the ester linkage. On exposure to UV-light, bifenthrin was decomposed almost completely in concentrations of 10 and 100 ppm in 24 hr but decomposed about 80% in 1,000 ppm. Bifenthrin was immobile in soil column system and on soil thin-layer chromatography system. Mostly bifenthrin remained in the 0-2.0㎝ layer of soil column and soil TLC.

• Korean Journal of Environmental Agriculture
• /
• v.11 no.2
• /
• pp.116-124
• /
• 1992

This study was conducted to elucidate degradation pattern of two synthetic pyrethroid insecticides, bifenthrin having 2-methylbiphenyl group and cyhalothrin having ${\alpha}$-cyano benzyl ester group in theirs alcohol moiety, in two soils and aqueous media under laboratory conditions. The half-life of bifenthrin was 85.1 days and 12,4 days in Chilgok and Bokhyen soil of aerobic upland condition, respectively, and that of cyhalothrin was 54.6 days and 32.2 days. Bifenthrin and cyhalothrin were degraded very slowly under anaerobic flooded condition and sterilized. Their degradation seemed to be mainly mediated by aerobic microorganisms in soil. Bifenthrin and cyhalothrin were degraded more rapidly in Bokhyen soil with rich organic matter than Chilgok soil. Cyhalothrin was degraded 30 days faster than bifenthrin under aerobic upland condition of two soils. Cyhalothrin was degraded more than bifenthrin in alkaline solution of pH 10, but cyhalothrin and bifenthrin were degraded very slowly in acidic solution of pH 2 and 6.

• The Korean Journal of Pesticide Science
• /
• v.13 no.4
• /
• pp.241-248
• /
• 2009

Pre-Harvest Residue Limit (PHRL) of bifenthrin during cultivation of grape was established by utilizing the dissipation curve and biological half-life of bifenthrin calculated from the analysis of 0, 1, 2, 3, 5, 7, 10, 15 days after treatment of bifenthrin. Grape sample was extracted and partitioned with acetonitrile and dichloromethane, respectively, and bifenthrin was determined with GC/ECD. Limit of quantitation (LOQ) of bifenthrin was 0.01 ng. Recoveries at two fortification levels of 0.1 and $0.5\;mg\;kg^{-1}$ were $104.08\;{\pm}\;1.24$ and $92.25\;{\pm}\;3.13%$, respectively. The biological half-lives of bifenthrin were about 21 days at standard application rate, while, 23 days at double application rate. Dissipation of bifenthrin on grape was not influenced by growth dilution effect. The PHRLs of bifenthrin were recommended as 0.60 and $0.55\;mg\;kg^{-1}$ for 10 and 5 days before harvest, respectively.

• Korean Journal of Environmental Agriculture
• /
• v.34 no.3
• /
• pp.223-229
• /
• 2015

BACKGROUND: It is important to understand residual patterns of pesticides applied on crops for ensuring their safety in agricultural products. However, there are few studies on the residual patterns of pesticides in minor crops, which are small in cultivation area. In this study, residual amounts of bifenthrin and chlorfenapyr sprayed on perilla leaf as a minor crop were investigated to know their residual patterns. METHODS AND RESULTS: Bifenthrin and chlorfenapyr were sprayed 2 or 3 times on perilla leaves at a week interval prior to harvest, and the perilla leaves were collected at 0, 1, 3, 5 and 7 days after the final application of pesticides. Recoveries for residual analysis of pesticides spiked on perilla leaves with concentrations of 0.1 and 0.5 mg/kg were 81.9-104.8%. The residual amounts of pesticides interpreted using first order kinetics model show that dissipation constants of bifenthrin and chlorfenapyr in perilla leaves were 0.0724-0.0535 and $0.0948-0.0821day^{-1}$, respectively. In addition, the dissipation half-lives in perilla leaves were 9.6-12.9 days for bifenthrin and 7.3-8.4 days for chlorfenapyr. When pre-harvest residue limits (PHRL) of bifenthrin and chlorfenapyr at 10 days before harvest calculated on the basis of the dissipation constants and maximum residue limits of the pesticides were calculated as 17.1 for bifenthrin and 15.9 mg/kg for chlorfenapyr. CONCLUSION: Therefore, the PHRL calculated using the time-dependant residual patterns of pesticides in perilla leaves and their regression analysis may be used as experimental evidences in order to ensure the safety of pesticides in perilla leaves before harvest.

• Korean journal of applied entomology
• /
• v.36 no.1
• /
• pp.105-110
• /
• 1997

Mixture study of bifenthrin and prothiofos was conducted to control insecticide resistant diamondback moth (DBM), Plutella xylostella, which had shown 581, 18, 19, 11 fold resistance to fenvalerate, cypermethrin, furathiocarb, and prothiofos in Chinju strain, respectively and 38 and 9 fold resistance to fenvalerate and furathiocarb in Seosang strain, respectively. Optimal mixture ratios of bifenthrin and prothiofos was selected against Seosang strain of DBM by leaf dipping method in laboratory and by field test. Maximum co-toxicity coefficient by dipping method was shown at a ratio of 1:50 mixture of bifenthrin 1EC and prothiofos 50EC in active ingredient(a.i.) by 243.2 and then suddenly decreased. The mixed formulation from the dipping test was examined at the cabbage field of Seosang, Hamyang. Although insecticides were reduced to half, control efficacy was similar to farmer's conventional method. In addition, the mixture combination was also more effective against Chinju DBM population which had very high level of resistance to several representative insecticides. Mixture methods of insecticides will be effective countermeasures to the resistance problem of pests.

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

• Journal of Environmental Science International
• /
• v.12 no.11
• /
• pp.1173-1179
• /
• 2003

Laboratory sorption isotherm batch studies have been attempted to elucidate interaction of synthetic pyrethroids (bifenthrin and permethrin) with sediments and their fractions. As a nonlinear isothermal model, the Freundlich equation was applied to sorption results obtained from sediments to investigate the relationship between synthetic pyrethroids and sediments containing different amounts of organic carbon. Results demonstrated that the sorption capabilities of bifenthrin and cis- and trans-permethrin was in the order of bifenthrin, cis-permethrin and trans-permethrin, respectively, indicating that adsorbed bifenthrin was the most stable followed by cis- and trans-permethrin in all sediments. Their sorption capability was closely related to organic carbon contents in sediments. Higher sorption was observed in sediments containing higher organic carbon contents. Sorption study extended into the fractions, clay and humic acids, extracted from a sediment, indicated that higher sorption capacity in humic acids occurred than in the clay of both examined bifenthrin and permethrin. This study demonstrates the sorption of synthetic pyrethroids with sediments, and will help in the understanding of the transport and fate of synthetic pyrethroids existing in field sediments.

• Toxicological Research
• /
• v.25 no.1
• /
• pp.41-45
• /
• 2009

This study was conducted to monitor the level of bifenthrin residues in pear sprayed with 2% bifenthrin wettable powder (WP) at the recommended rate at four different schedules prior to harvest. The target analyte was extracted with acetone, partitioned into dichloromethane, and then purified by florisil chromatographic column. The residue determination was performed on a DB-5 capillary column using GC with electron capture detector (ECD). Linearity of this method was quite good ($r^2$ = 0.9951) in the concentration ranged from 0.2 mg/kg to 10 mg/kg. Recovery test was carried out at two concentration levels, 0.2 mg/kg and 1.0 mg/kg, in three replicates, and their rates were from 82.9% to 107.2%. No quantitative bifenthrin was detected in pear of all kinds of treatments including the treatment sprayed 4 times until 7 days before harvest. This sensitive and selective method can be used to monitor the trace residual amounts of bifenthrin in pear in a quite low concentration level.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.9
• /
• pp.1258-1264
• /
• 2009

The removal effects of two commonly used pesticides of Bifenthrin and Metalaxyl during preparation and fermentation of kimchi were studied. The two pesticides were applied to Baechu cabbages intentionally for 20 seconds; the applied amounts of Bifenthrin and Metalaxyl were 3.02$\pm$0.09 ppm and 6.79$\pm$0.17 ppm, respectively. The Baechu cabbages were washed by water 3 times. Then the residual amounts of the two pesticides of Bifenthrin and Metalaxyl were measured and the removal rates were 21.7% and 16.1%, respectively. When Baechu cabbages were brined with 10% salt solution for 12 hours after the application of the two pesticides, the removal rates significantly increased to 98.7% and 60.8%, and when brined and washed 3 times by water, the removal rates even more increased to 99.7% and 73.4% respectively. Then we made kimchi and investigated the quantities of the residual pesticides during the fermentation at $4^{\circ}C$ for 3 weeks. The residual amounts of the pesticides in kimchi decreased in a time dependent manner, finally the amounts of the pesticides to 0.35$\pm$0.04 ppm and 0.48$\pm$0.06 ppm while the removal rates of the two pesticides were 57.8% and 81.0%, respectively. When the kimchi was fermented at $4^{\circ}C$ and $10^{\circ}C$ for 3 weeks, the removal rates of Bifenthrin were 57.8% and 72.2% and those of Metalaxyl were 81.0% and 85.6%, respectively. Consequently, it appeared that the residual pesticides can be removed during preparation, especially brining; the fermentation process of kimchi also removed the residual pesticides effectively, especially at higher temperature and long period.

• The Korean Journal of Pesticide Science
• /
• v.13 no.2
• /
• pp.79-86
• /
• 2009

In order to elucidate the residual characteristics of the insecticides, bifenthrin and imidacloprid, the pesticides were sprayed onto the squash and their residues were analyzed with GC-ECD and HPLC. Detection limits of the pesticides were $0.005\;mg;kg^{-1}$ and recoveries of bifenthrin and imidacloprid in squash were from 100.87 to 104.31 and from 79.71 to 92.54%, respectively. Half-lives of bifenthrin and imidacloprid in squash were from 1.8 to 2.9 and from 1.5 to 2.5 days, respectively. Initial concentration of bifenthrin and imidacloprid sprayed at the recommended rate and double rate of recommendation were less than their MRLs. And also, residueal concentrations of the pesticides were rapidly decreased in squash with time. At harvest, estimated daily intakes (EDIs) of the pesticides were less than 0.6% of their acceptable daily intakes (ADIs).