• Korean Journal of Environmental Agriculture
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• v.29 no.3
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• pp.257-265
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• 2010

In this study, the residual levels of four insecticidal compounds (lambda-cyhalothrin, lufenuron, thiamethoxam, and clothianidin) were monitored in the pomegranate, in order to assess the risk to consumers posed by the presence of such residues. The insecticides were applied at the recommended dose rates onto pomegranate trees. The samples were then collected at harvesting time after several treatments (two, three, and four treatments). After sample preparation progressed through the clean-up procedure, lufenuron, thiamethoxam, and clothianidin residues were analyzed via a HPCL-UVD, and the lambda-cyhalothrin residue was analyzed via a GC-${\mu}ECD$. The versatility of this method was evidenced by its excellent linearity (>0.9998 to 1) at broad concentration ranges. The mean recoveries evaluated from the untreated sample spiked with two different fortification levels ranged from 72.45 to 113.90%, and the repeatability (as a relative standard deviation) resulted from triplicate recovery tests was in a range from 0.80 to 11.75%. The residues of all insecticides determined from treated pomegranate samples and their LOD levels (lunfenuron, 0.01; lambda-cyhalothrin, 0.005; thiamethoxam, 0.01; clothianidin, 0.02 mg/kg) were much lower than their MRLs (0.5 mg/kg).

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.122-129
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• 2020

BACKGROUND: Dissipation patterns of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry grown in plastic-covered greenhouse were evaluated at 7 intervals including the preharvest interval after application. This study was performed to determine the residue concentrations, half-lives and dissipation rates in strawberry for the harvest periods. METHODS AND RESULTS: Acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam were applied in accordance with critical good agricultural practices for strawberry. Strawberry samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after application. Quantitaion was performed by HPLC/DAD and HPLC-MSMS system with C₁₈ column. The limit of quantitation (LOQ) values varied between were 0.00025~0.05 mg/kg on strawberry. The recoveries of acequinocyl, clothianidin, diflubenzuron, thiacloprid and thiamethoxam at two concentrations ranged from 70.9~104.9% on strawberry. The half-lives of pesticide dissipation on strawberry for two fields ranged from 1.3~8.2 days. The dissipation rates were evaluated according to the statistics method with a 95% confidence. CONCLUSION: The residue levels of insecticides (acequinocyl, clothianidin, diflubenzuron, thiacloprid, and thiamethoxam) on strawberry at 0-day after application were below the specified values by Korean MRL. To estimate dissipation rate constant of pesticides on crop for harvest periods, it is important to set the pre-harvest residue limit for human health and consumer protection in Korea.

• The Korean Journal of Pesticide Science
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• v.20 no.2
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• pp.133-137
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• 2016

In Korea, six mealybug species have been reported on pears. This study investigated the occurrence of mealybugs in 19 pear orchards from 2013 to 2014. Two species, Crisicoccus matsumotoi Siraiwa (Hemiptera: Pseudococcidae) and Pseudococcus comstocki Kuwana were mainly found. The dominant species was C. matsumotoi identified on 73% of infested fruit. Toxicities of 14 registered insecticides (Buprofezin+Acetamiprid EC, Buprofezin+Amitraz EC, Buprofezin+Clothianidin SC, Buprofezin+Dinotefuran WP, Buprofezin+Etofenprox WG, Buprofezin+Thiacloprid SC, Buprofezin+Thiamethoxam SC, Benfuracarb WG, Acetamiprid WP, Clothianidin SC, Dinotefuran WG, Thiacloprid SC, Thiamethoxam WG, Sulfoxaflor SC) commonly used to control P. comstocki were evaluated to C. matsumotoi nymphs and adults at the recommended concentration. As a results, all insecticides exhibited strong insecticidal activity with 100% mortality of both nymphs and adults. These results indicate that the 14 insecticides can be used in control for C. matsumotoi in field.

• The Korean Journal of Pesticide Science
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• v.16 no.2
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• pp.163-170
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• 2012

Nineteen registered insecticides including 8 mixed formulations with buprofezin and 11 single formulations which is not including buprofezin were evaluated by spray application for their toxicity against adult and nymph of citrus mealybug, Planococcus citri. Five mixed formulations with buprofezin such as buprofezin 15EC+acetamiprid 4EC, buprofezin 10SC+clothianidin 3SC, buprofezin 20WP+dinotefuran 15WP, buprofezin 20SC+thiacloprid 5SC, and buprofezin 20SC+thiamethoxam 3.3SC showed high insecticidal activity (>93%) against nymph and adult of P. citri. Insecticidal activities of EPN 45EC, fenitrothion 50EC and methidathion 40EC in organophosphorous group showed 90 to 93% against nymph only. In addition to, insecticidal activities of acetamiprid 8WP, clothianidin 8SC, dinotefuran 20WG and thiamethoxam 10WG in neonicotinoids group showed above 90% against nymph only. In systemic and residual effect, five mixed formulations that was already proved to have high insecticidal activity showed low toxicity with below 60% against $3^{rd}$ instar nymph of P. citri in tomato and rose under greenhouse. Control efficacy of five mixed formulations with buprofezin was above 90%, 80% and 70% at 5 days after treatment (DAT), 10 DAT and 15 DAT, respectively.

• Korean Journal of Environmental Agriculture
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• v.39 no.2
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• pp.106-113
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• 2020

BACKGROUND: Bumblebees have been shown to be very effective pollinators for most greenhouse tomatoes. Neonicotinoid insecticides are one of the most widely used pesticides in tomato crops in Korea. METHODS AND RESULTS: This study was carried out to investigate the toxicity of four neonicotinoid insecticides (clothianidin, dinotefuran, imidacloprid and thiamethoxam) to bumblebees based on the OECD guidelines (No.246, 247). The 48 hr LD₅₀ (㎍ a.i. /bumblebee) values in the acute contact toxicity tests were determined as follows: clothianidin, 0.467; dinotefuran, 3.741; imidacloprid, 3.967; and thiamethoxam, 0.747. The 48 hr LD₅₀ values in the acute oral toxicity tests were determined as follows: clothianidin, 0.005; dinotefuran, 0.056; imidacloprid, 0.325; and thiamethoxam, 0.018. The acute contact and oral toxicity of the test insecticides to bumblebees from most to least toxic was clothianidin > thiamethoxam > dinotefuran > imidacloprid. CONCLUSION: This study provided the basic toxicological data of neonicotinoid insecticides for bumblebees. In the near future, acute toxicity and mixture toxicity of other pesticides to bumblebees could be determined using this method.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.11-17
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• 2019

Strawberries are one of the main commodities in Korea and have been exported over 40 million dollar. Because the strawberry cultivation using hydroponics has increased, treatment of pesticide by drenching draw interest recently. However, detailed researches for drenching treatment of pesticide are limited, which results in difficulties in proper pesticide applications in agricultural fields. To activate use of drenching and improve safety in agricultural products, In this study, time-dependent residual characteristic of pesticides were compared with between different applications of pesticides in strawberries. The characteristics of azoxystrobin, prochloraz and thiamethoxam were investigated with drenching treatment at different applications: the time of treatment, concentration etc. at hydroponic cultivation for 40 days. Azoxystrobin and prochloraz were not detected at 14 day after application. Thiamethoxam was detected from 0.02 to 0.85 mg/kg. Crop uptake of pesticides was strongly affected with octanol-water partition coefficient and solubility in water. Residual amount in crops are highly dependent on the concentration of active ingredient of pesticides.

• Journal of Food Hygiene and Safety
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• v.37 no.1
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• pp.1-8
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• 2022

In this study, the pesticide residues in 106 commercial cereal grains were monitored from February to July 2021. For the investigation, 40 domestic and 66 imported products from large, small-to-medium sized offline and online distribution channels, were collected and analyzed by using the multiresidue method for 341 pesticides on GC/ECD, GC/NPD, GC/MSMS, UPLC/PDA, HPLC/FLD, LC/MSMS. Pesticides were detected in total of 8 samples (7.5%), of which one was from big box retailers, two from small and medium-sized distribution stores, and five from online shopping mall. Five (4.7%) samples were found to have pesticide residues greater than the maximum residue limits (MRLs). The detected pesticides in kidney beans (1 case), mung beans (6 cases), and sorghum (1 case), were MGK-264, chlorpyrifos, thiamethoxam, malathion, piperonyl butoxide, and pirimiphos-methyl. Specifically, an excessive amount of thiamethoxam was found from the imported mung bean (5 cases).

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2001.05a
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• pp.71-71
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• 2001

• The Korean Journal of Pesticide Science
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• v.12 no.4
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• pp.382-390
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• 2008

This study was performed to evaluate the acute toxicity and residual toxicity of the 69 kinds of agrochemicals (41 insecticides, 18 fungicides, and 10 acaricides) against honeybee, Apis mellifera and bumblebee, Bombus terrestris. According to the IOBC standard, the toxicity showed below 30% was classified as non-toxic. Among 41 insecticides, five insecticides (acetamiprid, chlorfenapyr, thiacloprid, milbemectin, and buprofezin+amitraz) against the honeybee; eight insecticides (methomyl, thiodicarb, acetamiprid, chlorfenapyr, thiacloprid, abamectin, spino sad, buprofezin+amitraz) against the bumblebee did not show any toxic effect. Therefore, it thought to being safe. Other 18 fungicides and 10 acaricides were safe against the honeybee and bumblebee. In residual toxicity against the honeybee, eight insecticides (dichlorvos, methomyl, imidachlorprid, emamectin benzoate, spinosad, cartap hydrochloride, chlorfenapyr, and endosulfan) among 41 insecticides tested were safe at three days after treatment; however, sixteen insecticides (dimethoate, fenitrothion, fenthion, methidathion, phenthoate, pyraclofos, fenpropathrin, clothianidin, dinotefuran, thiamethoxam, abamectin, acetamiprid+ethofenprox, acetamiprid+indoxacarb, bifenthrin+imidacloprid, ethofenprox+phenthoate, imidacloprid+methiocarb) still remain high toxicity at eleven days after treatment. Against the bumblebee, residual toxicity showed as safe in seven insecticides (dimethoate, methidation, a-cypermethion, ethofenprox, indoxcarb, chlorpyrifos+a-cypennethrin, esfenvalerate+fenitrochion) at three days after treatment; however, eight insecticides (fenitrothion, pyraclofos, clothianidin, fipronil, acetamiprid+ethofenprox, chlorpyrifos+bifenthrin, ethofenprox+phenthoate, imidacloprid+methiocarb) still showed high toxicity at seven days after treatment. From above results, it will be useful information to select insecticides being safe and effective against the honeybee and bumblebee.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.627-636
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• 2023

Bemisia tabaci Gennadius, one of the most invasive insect pests, has spread quickly nationwide since it was introduced to South Korea in 2008. The use of insecticides is the main management strategy for this pest, but the control efficiency has been decreased due to insecticide resistance. We collected 12 local B. tabaci populations to investigate the regional differences in efficiency and observed the mortality from 14 commercial insecticides applied at recommended concentrations (RC) and dilutions (0.1 RC and 0.01 RC) using the leaf dipping bioassay. Except for etofenprox (46-64%), thiamethoxam (37-60%), pyriproxyfen (21-61%), and pyridaben (61-65%), the other insecticides showed excellent insecticidal efficacy of 70% to 100% at their RC. In particular, flupyradifurone, emamectin benzoate, and cyantraniliprole showed high insecticidal efficacy of over 90% in all of the tested populations. Some insecticides that rapidly decreased in activity (less than 30%) at diluted concentrations or showed high resistance levels in nearby regions were classified for cautious use due to the possibility or potential to develop resistance. The results provide selected insecticides for B. tabaci control by region and could contribute to reducing insecticide abuse and increasing insecticidal efficiency in farming fields.