• Korean journal of applied entomology
• /
• v.59 no.1
• /
• pp.41-54
• /
• 2020

Two mosquito species were collected in still-water near farming area in Andong, Korea. Based on morphological characters, these two mosquitoes were identified as Aedes koreicus and Culex vagans, respectively. DNA barcode analyses supported the identification. An entomopathogenic bacterium, Bacillus thuringiensis subsp. israelensis (BtI), exhibited insecticidal activities against the two mosquito species and its virulence was more potent than that of B. thuringiensis subsp. kurstaki. It has been known that the bacterial metabolites of Xenorhabdus spp. suppress insect immunity and enhance pathogenicity of B. thuringiensis. This study tested the effect of the bacterial culture broth of Xenorhabdus spp. on enhancing BtI pathogenicity. Among three Xenorhabdus spp., culture broth of X. ehlersii (Xe) was relatively effective to enhance BtI pathogenicity against both mosquito species. Indeed, organic extracts of Xe culture broth suppressed the hemocyte-spreading behavior, suggesting the presence of immunosuppressant in the culture broth. These results suggest a formulation of BtPlus by mixing BtI spore and Xe culture broth to be applied to control the two mosquito species.

• The Korean Journal of Pesticide Science
• /
• v.15 no.3
• /
• pp.303-309
• /
• 2011

This study was carried out to investigate the evaluation of insecticidal efficacy and control effect in field of 10 environmental-friendly agricultural materials (EFAM) and seasonal occurrence at the vineyards to the Lycorma delicatula. L. delicatula nymphs occurred from late May to late August the highest early June (1st nymph) while adults occurred from late July to November with the highest peak of early October (preovipositing female) in 2010. Total population density of L. delicatula was the highest in early June. For the 3rd~4th nymphal instars and adults, EFAM (Spider, Jindikap-plus and Byejin-${\alpha}$) showed perfect insecticidal activity 2hour after treatment. Seoncho showed insecticidal activities 96.7% within 48 hour. Residual effects between EFAM showed 55.5% Spider at recommended concentration at 7 days after treatment(DAT), the other EFAM had low efficacy. Jindikap-plus and Spider showed 99% control value on nymphs in the field test at 3DAT, appeared control value more than 90% at 7DAT. Also, the control effects of Jindikap-plus and Spider were showed the adult mortality of 100% and 98.2% respectively at 3DAT, 90.6% and 84.6% respectively at 7DAT. Whereas the other EFAM had low efficacy. Jindikap-plus and Spider were excellent control effects compared with Acetamiprid WP.

• 보존과학연구
• /
• s.32
• /
• pp.25-35
• /
• 2011

Wood vinegar and Asarum sieboldii Miquel were selected as candidate materials showed antimicrobial activity and insect repellent activity. These natural pesticides have its own color and these could cause color difference on fabric materials. In the present study, we investigated the color difference of undyed and dyed fabrics to evaluate negative effect of wood vinegar and A. sieboldii Miquel. Undyed and dyed fabrics were exposed to natural pesticides of various concentrations for six months in relative humidity 70% and temperature $28^{\circ}C$. After exposure of pesticides, color difference (${\Delta}E*$) were investigated at two weeks intervals for six months. As a results, dyed cotton, silk and undyed silk fabrics exposed wood vinegar were not nearly changed in their colors, but color of only undyed cotton fabric was clearly changed by wood vinegar. Especially color difference by wood vinegar on undyed cotton fabric was most distinct as the concentration increased. On the other hand, all of fabrics exposed A. sieboldii Miquel were not nearly changed in their colors for six months. Therefore, this study first suggests that wood vinegar and A. sieboldii Miquel as natural insecticides could be used to conserve for textile cultural properties from insects and microorganism, but wood vinegar couldn't use the high concentration on undyed cotton fabric.

• Korean Journal of Environmental Agriculture
• /
• v.8 no.1
• /
• pp.47-54
• /
• 1989

This study was conducted to investigate insecticide toxicities to a honeybee, Apis cerana F. being raised in Korea and its detoxifying enzyme activities. In order to determine the appropriate usage of insecticides, median effective dose and detoxifying enzyme activities to seven insecticides were observed. Various detoxifying enzymes, including microsomal oxidases, glutathione S-transferases, esterases, and DDT-dehydrochlorinase were assayed in the midguts of adult worker bees as the enzyme source. Of the insecticides used, $LC_{50}$ value in DDT treatment was the highest as 19ppm, and that in EPN treatment was the lowest as 0.75ppm. Sublethal exposures of honeybees to various insecticides had some effects on microsomal enzyme activities. Aldrin epoxidase activity was inhibited by malathion and demeton S-methyl treatment. N-demethylase activity was induced by carbaryl treatment. Of the glutathione S-transferases, aryltransferase(DCNB conjugation) activity was significantly induced by diazinon, and moderately induced by malathion. Of the esterases, ${\alpha}-NA$ esterase activity was moderately inhibited by malathion and permethrin. Carboxylesterase and acetylcholinesterase activity were not affected by the sublethal exposure of honeybee to the insecticides. Sublethal exposure of honeybee to the insecticides had no effect on DDT- dehydrochlorinase activity, except carbaryl, malathion and demeton S-methyl were inhibited.

• Applied Biological Chemistry
• /
• v.31 no.3
• /
• pp.241-248
• /
• 1988

In order to determine the approptiate usage of insecticides to honeybee(Apis mellifera L.), median effective dose to seven insecticides were studied. $LC_(50)$ value of DDT was the highest as being 58 ppm, and that of EPN was the lowest as being 1.61ppm. Various detoxifying enzymes from the midget cf adult worker bee, including microsomal oxidases, glutathione Stransferases, esterases, and DDT-dehydrochlorinase were assayed. Effects of various insecticides on microsomal enzyme activities were as follows: Aldrin epoxidase activity was inhibited by malathione and permethrin treatment. N-demethylase activity was induced by diazinon and EPN treatment and O-demethlase activity was induced by diazinon treatment. Of the glutathione S-transferases, aryltransferase(DCNB conjugation) activity was significantly induced by diazinon, and moderately induced by permethrin. Of the esterases, ${\alpha}-NA$ esterase activity was moderately inhibited by malatjione and permethrin. Acetylcholinesterase activity was not affected by the sublethal exposure of honeybee to the insecticides. Sublethal exposure of honeybee to the insecticides had no effect on DDT-dehydrochlorinase activity, except carbaryl and permethrin were significantly induced.

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

• Korean journal of applied entomology
• /
• v.43 no.1
• /
• pp.55-60
• /
• 2004

This experiment was conducted to improve activity of Spodoptera litura Nucleopoly-hedrovirus (SINPV) combined with organic and functional matters. In combination of SINPV mixed with organic matters, LT$_{50}$ values of SINPV 1.0${\times}$10$^{5}$ PIBs/$m\ell$ combined with boric acid of 2,000 ppm were 4.5 days. It was 1.5 days shorter than SINPV 1.0${\times}$10$^{5}$ PIBs/$m\ell$ alone. The body weight of larva infected with SINPV 1.0${\times}$10$^{5}$ PIBs/$m\ell$ combined with boric acid of 2,000ppm was not increased, and S. litura was completely dead in 7 days after treatment. It suggested that addition of boric acid in SINPV application enhanced the pathogenicity against S. litura larvae. In laboratory experiment of combination of SINPV with functional matters, LT$_{50}$values of SINPV 1.0${\times}$10$^4$ PIBs/$m\ell$ alone were 7.3 days, but those of SINPV 1.0${\times}$10$^4$ PIBs/$m\ell$ with electrolyzed oxidizing water, pyroligneous liquor or kitosan were 10.4, 9.3 and 11.2 days, respectively. Functional matter could be suppressed the insecticidal activity of SINPV

• Korean journal of applied entomology
• /
• v.51 no.4
• /
• pp.389-395
• /
• 2012

Stored grain insects appear frequently as grains are harvested, stored, and distributed on the market. Producers mostly depend on chemical fumigants to control and repel insect pests, but this application of chemicals may cause side effects for humans and the environment. Safer control approaches, including the use of natural products are required, and in this study, we assessed the control effect of essential oils on stored grain insects. The essential oils of 8 plant species from 6 families were tested for their fumigant toxicity and repellent effects using a Y-tube Olfactometer against Sitophilus zeamais adults. Pennyroyal and tea tree oil respectively exhibited 97% and 63% mortality at $10{\mu}{\ell}L^{-1}$ air concentration in tested fumigant toxicity. Of particular note, pennyroyal oil ($LT_{50}$, hour=3.87) showed higher adulticidal activities than tea tree oil ($LT_{50}$, hour=4.09). When assessing repellent effects, using a Y-tube Olfactometer at $10{\mu}{\ell}$/filter paper concentration, the cedarwood, cinnamon, cypress, patchouli and pennyroyal essential oils showed potent repellent activities against Sitophilus zeamais adults. Cinnamon, cypress and pennyroyal essential oils showed notably high repellent activities of 82.4%, 80.0% and 86.7%, respectively, at $1{\mu}{\ell}$/filter paper concentration.

• Korean journal of applied entomology
• /
• v.63 no.1
• /
• pp.53-61
• /
• 2024

The susceptibility of Aphis gossypii populations collected from three fields (WJ, CC, and GS) was evaluated to three insecticides (afidopyropen, chlorfenapyr and cyantraniliprole) and three binary mixtures. Three field populations showed resistance ratios of over 100 to all insecticides. The Combination Index (CI), %M_(synergism), Co-Toxicity Coefficient (CTC), Wadley Ratio (WR), Synergism Ratio (SR) and Abbott Ratio (AR) were used to evaluate combined effect of the insecticides. Afidopyropen + chlorfenapyr (CI ≤ 0.16; %M_(synergism) ≥ 94; CTC ≥ 764.5; WR ≥ 6.4; SR ≥ 6.9 and AR ≥ 1.1) showed a synergism in all filed populations. WJ and CC populations showed a synergism in all binary mixtures of insecticides, but GS population showed an antagonism for chlorfenapyr + cyantraniliprole (CI, 1.63; %M_(synergism), 30; CTC, 64.0; WR, 0.6 and AR, 0.54) and afidopyropen + cyantraniliprole (CI, 6.7; %M_(synergism), 1; CTC, 19.8; WR, 0.2 and AR ≤ 0.55). All mixtures (afidopyropen + chlorfenapyr, chlorfenapyr + cyantraniliprole and afidopyropen + cyantraniliprole) showed a control value of over 99% after 21 days of treatment in the field. This study highlights that binary mixtures of three insecticides serve as an effective control strategy for A. gossypii.

• Journal of the Korean Wood Science and Technology
• /
• v.41 no.4
• /
• pp.269-275
• /
• 2013

Antifungal and insecticidal activity of Korean traditional medicinal plants was carried out to develop natural material for the development of organic cultural heritage conservation. As a result, Phellodendron amurense fruit was finally selected as a candidate of antifungal and insecticidal natural material. An novel active compound was purified from the ethylacetate fraction of Phellodendron amurense fruits using silica gel and Sephadex LH-20 column chromatography and PTLC. The compound was obtained as yellow oil form; UV ${\lambda}_{max}$(MeOH): 260 nm. The chemical structure of novel compound was determined as (4'-ethyl-2'-methylfuranyl)-6-methoxy-7-methylnona-2E,4E,6Z,8E-tetraenoic acid on the basis of various NMR experiments including $^1H$- and $^{13}C$-NMR, HMQC, HMBC and ESI-mass spectrum.