• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.363-370
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• 2013

Susceptibility of each developmental stage of Phthorimaea operculella (Lepidoptera: Gelechiidae) were investigated using 16 insecticides which are available in the market in Korea. For the eggs and pupae, only spinosad showed a 71.1% inhibition rate for egg hatchability and a 66.7% inhibition rate for emergence. For the 3rd instar larvae, the feeding toxicities were over 90% for fenitrothion ($LC_{50}$ 336.6 ppm), esfenvalerate ($LC_{50}$ 8.6 ppm), ethofenprox ($LC_{50}$ 35.7 ppm), and emamectin benzoate ($LC_{50}$ 0.05 ppm). Furthermore, the contact toxicities were over 90% for esfenvalerate ($LC_{50}$ 0.87 ppm), ethofenprox ($LC_{50}$ 16.5 ppm), emamectin benzoate ($LC_{50}$ 0.53 ppm), and spinosad ($LC_{50}$ 2.48 ppm) at the recommended concentrations. Deltamethrin and spinosad yielded 100% mortality for adult P. operculella 48 h after treatment. The adult female fecundity was inhibited by deltamethrin, esfenvalerate, emamectin benzoate, spinosad and dinotefuran, which were significantly different from the control. The adult longevities (7.3-8.3 days) were reduced by approximately 1-2 days compared with the control (9.3 day). The emamectin benzoate maintained 100% insecticidal activity 14 days after treatment and ethofenprox maintained over 90% activity 7 days after treatment.

• The Korean Journal of Mycology
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• v.30 no.1
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• pp.44-49
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• 2002

The study was conducted to isolate and identify insecticidal bacteria for biological control of larvae of mushroom fly, Lycoriella mali, which is one of serious pests to oyster mushrooms during its cultivation period. Among eight bacteria isolated from the soil in the oyster mushroom beds and the dead body of L. mali, two bacteria, Bti-D and Bti-U showed more toxicity with mortality rate than other six-bacteria isolates. The two bacteria showed more toxicity in three instar of the period of development of the mushroom fly than in other instar. Symptoms of the larvae of L. mali infected by the two bacteria developed as follows: at the early infection, the front middle gut changed color to light brown, the middle gut to brown, whole body to black brown, and eventually, the fly died. For the identification of these isolates, cultural and biochemical characteristics by Bergey's manual and Biolog system, cell morphology by TEM, endospore and endotoxin by phase-contrast microscope, and test using 33H antisera were examined. According to the results, these two isolates, Bti-D and Bti-U were identified as Bacillus thuringiensis subsp. israelensis respectively.

• The Korean Journal of Pesticide Science
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• v.2 no.3
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• pp.126-136
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• 1998

For the purpose of effective control strategy of the melon aphid, Aphis gossypii and the diamondback moth, Plutella xylostella, thiamethoxam and 3 other insecticides in different classes were used with bioassay test methods in laboratory and greenhouse. They were examined to evaluated and compared with contact toxicity, stomach toxicity, rapid action, systemic action, and residual effect of imidacloprid, thiamethoxam (nicotinoids), acephate (organophosphorates), and carbosulfan (carbamates). As results of contact toxicity responses of A. gassypii against 4 insecticides using a spray application method, $LC_{50}$ values of acephate, carbosulfan, imidacloprid and thiamethoxam were 41.9, 5.2, 1.1, and 0.7 ppm. respectively. In the evaluation of stomach toxicity response of P. xylostella using a leaf-dipping method, with the 2nd instar larva $LC_{50}$ values of imidacloprid, thiamethoxam and acetamiprid were 64.9, 24.6 and 15.2 ppm, with the 3rd instar larva were 125.2, 42.7 and 27.8 ppm. and with the 4th instar larva were 241.1, 44.5 and 23.9 ppm, respectively. In the case of rapid action to A. gossypii using a spray application method after inoculation, $LT_{50}$ values of imidacloprid, thiamethoxam, carbosulfan, and acephate were 26.6, 28.0, 30.3, and 41.7 min. respectively. Otherwise, in the inoculation after applying compounds, $LT_{50}$ values of thiamethoxam, imidacloprid, and carbosulfan were 95.5, 118.0, and 122.9 min. respectively. Evaluating to systemic action from the abaxial surface to the adaxial surface of red pepper leaf with spray method, $LT_{50}$ values of thiamethoxam, imidacloprid, and carbosulfan were 162.2, 168.9, and 564.1 min. respectively. For the systemic action from the lower leaves to the upper leaves on red pepper, $LT_{50}$ values of carbosulfan, thiamethoxam, imidacloprid, and acephate were 2.3, 2.9, 3.0, and 8.8 days, respectively. In red pepper plant, $LT_{50}$ values of carbosulfan, imidacloprid, thiamethoxam, and acephate on the systemic action from the roots to the upper leaf were 0.6, 1.0, 1.0, and 13.8 days, respectively. As these results, it might be that thiamethoxam was excellent on systemic effect in red pepper. For the evaluation of residual effect on red pepper with A. gossypii, thiamethoxam and imidacloprid maintained high control effects as over 80% upto 10 days after treating compounds.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.193-203
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• 2023

Ethyl formate (EF) is a naturally occurring insecticidal compound and is used to control pests introduced from abroad, in quarantine, by a fumigation method. In particular, it is mainly used as a substitute for methyl bromide and is less toxic to humans and less harmful to plants. This study aimed to investigate the possible acute toxicity of EF to useful organisms, and how to reduce phytotoxicity in watermelon, zucchini, and oriental melon. After fumigation with EF for 2 h, the LC₅₀ values for earthworms, honey bees, and silkworms were 39.9, 7.09, and 17.9g m^-3, respectively. The degree of susceptibility to EF was in the order of earthworms, silkworms, and honey bees based on the LC₅₀ value, and EF fumigation induced stronger acute toxicity to honey bees. Phytotoxicity was observed in watermelon leaves treated with a concentration of 7.5 g m^-3 EF, and when treated with a concentration of 10.0g m^-3, it was confirmed that the edges of watermelon leaves were charred and seemed to be damaged by acids. Zucchini and melon, and other cucurbits, showed strong damage to the leaves when treated with a concentration of 10 g m^-3, and sodium silicate, at concentrations of 10% and 20%, was used to reduce phytotoxicity. Therefore, acute toxicity towards nontarget organisms and phytotoxicity during the fumigation of EF should be reduced for efficient agricultural pest control.

• The Korean Journal of Mycology
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• v.34 no.1
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• pp.7-14
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• 2006

Entomopathogenic fungus Cordyceps militaris is famous for its medicinal efficacies. It has been reported to have various pharmacological activities such as anti-tumour, insecticidal, antibacterial, immunomodulatory and antioxidant. In this study, we investigated the effect of the extract of C. militaris (MPUN8501), which was identified by the analysis of the nucleotide sequences of 5.8S ribosomal RNA, on the function of liver. C. militaris powder was extracted using hot water extracts method as time, volume and temperature and using method as differential polarity of organic solvent. Each fraction was tested for the improvement of hepatic enzyme alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) activity. The BuOH extracts (CME) had highest activity which was used for the test of toxicity and efficacy of C. militaris. The enhancing effect of CME on the activity of ADH and ALDH was much more than medicine, drink, natural tea etc. Thus CME promoted the resolution of alcohol and acetaldehyde in rats, inducing recovery to normal condition rapidly. Furthermore, oral administration of CME effectively protected the carbon tetrachloride-induced acute hepatic injury as revealed by the hematological parameters (levels of sGOT and sGPT) and histological observation. CME was ascertained to be safe by regulatory toxicity studies of single dose toxicity and genotoxicity. These results suggest that CME would be useful for the maintaining normal hepatic activity as a functional health food.

• Applied Biological Chemistry
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• v.22 no.2
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• pp.123-134
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• 1979

For the purpose of developing a microbial insecticide utilizing Bacillus thuringiensis Berliner, research was done and the following results were obtained. 1) As the freeze-dried matter of the cocoon-cooked water discarded from the filature contains much crude protein(51.825%) and a lot of inorganic salts, it can make a good nutrition source for the culture cf B. thuringiensis Berliner. 2) Based on the suspensibility, formula F-5 turned out to be the most suitable for insecticidal use. Its composition includes 0.2 g of the cell-spore-crystal mixture, 25 g of 200-mesh kaolin, 2.5 g of New Kalgen-NX-150, and 2.5 g of glycerine admixed with 8 ml of distilled water and granulated in 80-mesh size. 3) All the components of F-5, F-6 and F-7 are identical except that the amounts of cell-spore-crystal mixture of F-5, F-6, and F-7 are 0.2 g, 0.4 g, and 0.6 g, respectively. Accordingly, their physical properties are almost all the same. 4) Formulas F-5, F-6, and F-7 exhibited an excellent toxicity to Anomis mesogona Walker, Dendrolimus spectabilis Butler, and Margaronia perspectalis Walker at the concentration of 5%. 5) Formulas F-8 and F-9 which contain $NaHCO_3$ as one of their components showed a remarkably reduced toxicity to Anomis mesogona Walker and Dendrolimus spectabilis Butler than F-6 which does not contain $NaHCO_3$. 6) A maximum of $2.97{\times}10^9$ spores per ml was obtained by incubating B. thuringiensis in M-3 which has a pH of 7.05 and comprises 0.2% of ammonium sulphate and 0.8% of glucose dissolved in the cocoon-cooked water, with aeration for 96 hours. 7) Formula F-6 exhibited a somewhat reduced toxicity to Anomis mesogona Walker and Dendrolimus spectabilis Butler, when stored at room temperature for 70 days after formulation and it is desirable to keep it in a dark and cold place. 8) In held applications, formula F-6 showed a good activity in controlling Monema flavescens Walker. Margaronia perspectalis Walker, and Macrosiphum ibarae Matsumura.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.419-427
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• 2013

The insecticidal activity of 124 plant essential oils and control efficacy of six experimental spray formulations (SF) containing 0.25, 0.5, 1, 2.5, 5, and 10% of the selected oils was examined against both nymph and adult of the citrus flatid planthopper, Metcalfa pruinosa using direct contact applications (leaf dipping and spray). Reponses varied according to dose (1,000 and 500 mg/L). When exposed at 1,000 mg/L for 24 h using leaf dipping assay, 19 essential oils showed strong mortality (100%) among 124 essential oils screened. At 500 mg/L, 100% mortality was observed in cinnamon technical, cinnamon green leaf, cinnamon #500, cassia tree, citronella java and pennyroyal followed by origanum, thyme white, grapefruit, savory, fennel sweet, aniseed and cinnamon bark showed considerable mortality (93.3-80%) against nymphs of M. pruinosa. The moderate mortality (73.3-60%) was found in thyme red, tagetes, calamus, lemoneucalptus and geranium. Oils applied as SF-10% sprays provided 100 % mortality against adult M. pruinosa. One hundred mortalities were achieved in cinnamon technical at >SF-0.5 formulation, in cinnamon #500, cinnamon green leaf and penny royal at >SF-2.5. To reduce the level of highly toxic synthetic insecticides in the agricultural environment, the active essential oils as potential larvicides could be provided as an alternative to control M. pruinosa populations.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.2
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• pp.81-85
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• 2013

The stored-product insects have been a serious problem during the entire process of distribution on the food industry. Especially, the Indian meal moth (Plodia interpunctella) is one of stored-product insects which causes harm through penetrating into the food packaging. The objective of this study was to develop the anti-insect packaging material with fennel (Foeniculum vulgare) oil (FO). The FO has been selected for insecticidal substance against P. interpunctella, which was tested by fumigant toxicity assay. An anti-insect sachet was prepared by FO and filterpaper placed in a small paper bag. Repellent test was performed to evaluate the repellent activity of anti-insect sachet. In addition, the controlled release of FO from the anti-insect sachet was determined at $28^{\circ}C$ by gas chromatography (GC). It was demonstrated that FO was an effective substance against P. interpunctella. The mortality of FO was 56% at 800 mg/0.5 L in 120 h. In repellent test, the FO sachet showed effective repellency against P. interpunctella. The developed anti-insect sachet could be a promising source for insect repellent materials in food packaging.

• The Korean Journal of Pesticide Science
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• v.12 no.2
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• pp.192-196
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• 2008

This study examined the acaricidal activity of a new compound, K16776 against honeybee mite, Varroa destructor which is ecto-parasite of Apis mellifera. Acaricidal activity was performed using six acaricides, two Chinese commercial acaricides and one newly synthesized K16776 against V. destructor in the small container and in the bee hive. K16776 and amitraz exhibited 100% acaricidal activity against V. destructor without insecticidal toxicity to A. mellifera in the small container. The other acaricide was not activity. Applied to the bee hives, K16776 showed acaricidal activity as 98.7% ($250{\times}$) and 88.6% ($500{\times}$) and amitraz showed as 100% ($500{\times}$) and 90% ($1,000{\times}$), respectively. Made in China, Cao Suan Sha Man Pian and Wangs showed acaricidal activity as 56.9% and 66.7%, respectively. The result indicates that K16776 can be potentially useful control agent against honeybee mite, V. destructor.

• Korean journal of applied entomology
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• v.61 no.1
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• pp.101-108
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• 2022

Because of their specificity to target insects and relatively low toxicity to non-target organisms, insect growth regulators (IGRs) have been regarded as attractive alternatives to chemical insecticides. Commercially available IGRs are classified into juvenile hormone agonists (JHAs), ecdysone agonists (EAs), and chitin synthesis inhibitors (CSIs) according to their mode of action. Recently, JH-mediated interaction of methoprene-tolerant (Met), which is JH receptor, and its binding partners have been replicated in vitro using yeast cells transformed with the Met and FISC/CYC genes of A. aegypti. Using this in vitro yeast two-hybrid β-galactosidase assay, juvenile hormone antagonists (JHANs) have been identified from various sources including chemical libraries, plants, and microorganisms. As juvenile hormone (JH) is an insect specific hormone and regulates development, reproduction, diapause and other physiological processes, JHANs fatally disrupt the endocrine signals, which result in abnormal development and larval death. These results suggested that JHANs could be efficiently applied as IGR insecticides with a broad insecticidal spectrum. This review discuses JH signaling pathway mediated by Met and future prospects of JHANs as environmentally benign IGR insecticides.