Suigen, South Korea
Suigen, South Korea

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Lee D.-W.,Korea University | Chang K.-S.,Korea National Institute of Health | Kim M.J.,Nareso Co. | Ahn Y.-J.,Seoul National University | And 2 more authors.
Journal of Asia-Pacific Entomology | Year: 2015

The acaricial activity of 13 commercialized insecticides in Korea against the hard tick nymphs Haemaphysalis longicornis collected in a field was tested using nymph dipping and folded filter paper methods and a spraying-residual assay. In a nymph dipping bioassay, 100% mortality at all tested doses was observed in insecticides containing active ingredients such as phthalthrin 8% + d-phenothrin 2% + piperonyl butoxide 20%, deltamethrin 1.5%, pyrethrum 0.5%, lambda-cyhalothrin 5.5%, alpha-cypermethrin 10% and teflubenzuron 50%, whereas the insecticide containing etofenprox 5% + octachlorodipropyl ether 11% at recommended dose (RD) and 0.5 times RD showed 97 and 90% activity, respectively. Other insecticides containing alpha-cypermethrin 5%, polyoxyethylene isostearylether 10%, etofenprox 5%, bistrifluron 10% and Bti did not show any significant activity. In the folded filter paper contact test with nymph H. longicornis at RD, polyoxyethylene isostearylether 10%, deltamethrin 1.5% and alpha-cypermethrin 10% showed 100% mortality at 1 day after treatment (DAT). At 7 DAT, polyoxyethylene isostearylether 10%, deltamethrin 1.5% and lambda-cyhalothrin 5.5% exhibited 100, 93 and 87% mortality. Although the selected 5 insecticides showed strong mortality under laboratory conditions, their residual effect sprayed on field grown lawn leaves significantly decreased depending on DAT. Etofenprox 5% mixture (+ octachlorodipropyl ether 11%) only showed 93 and 80% mortality at 1 and 2 DAT, respectively. Polyoxyethylene isostearylether 10% gave 0% mortality at even 1 DAT and the other insecticides also showed 60-70% mortality at 1 DAT. These results indicate that pyrethroid insecticides gave good activity against the H. longicornis nymphs but their residual effect is within 1 DAT under field conditions. © 2015 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society.

Chae S.-H.,Seoul National University | Kim S.-I.,Nareso Co. | Yeon S.H.,Huons Co. | Perumalsamy H.,Seoul National University | Ahn Y.-J.,Seoul National University
Journal of Economic Entomology | Year: 2014

An assessment was made of the fumigant toxicity of 36 constituents from lemon balm oil (LBO) and summer savory oil (SSO) and another additional nine previously identified compounds of the oils, as well as of the control efficacy of four experimental spray formulations containing individual oils (0.5 and 0.1% sprays) and spinosad 10% suspension concentrate (SC) to females from B- and neonicotinoid-resistant Q-biotypes of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). Based on 24-h LC50 values, Q-biotype females (0.20 μg/cm3) were 40 times less susceptible to dichlorvos than B-biotype females (0.005 μg/cm3). Thymol (LC50, 0.35 μg/cm3) and carvacrol (0.56 μg/cm3) were the most toxic compounds toward Q-biotype females, followed by (1S)-( - )-borneol, α-terpineol, nerol, linalool, and carvone (1.06-1.38 μg/cm 3). The toxicity of these compounds was virtually identical toward both biotype females, indicating that the terpenoids and the insecticides (neonicotinoids and dichlorvos) do not share a common mode of action or elicit cross-resistance. The 0.5% spray of LBO, SSO, and spinosad 10% SC resulted in >90% mortality toward both biotype females. Global efforts to reduce the level of toxic synthetic insecticides in the agricultural environment justify further studies on LBO- and SSO-derived materials as potential contact-action fumigants for the control of B. tabaci populations. © 2014 Entomological Society of America.

Kim S.-I.,NARESO Co. | Lee D.-W.,Kyungsung University
Journal of Asia-Pacific Entomology | Year: 2014

Two commercialized essential oils and their constituent compounds were investigated for fumigant and contact activities against two grain storage insects, adults of the maize weevil (Sitophilus zeamais) and the red flour beetle (Tribolium castaneum). The two commercialized basil and orange oils showed strong fumigant and contact activities against S. zeamais and T. castaneum. The constituents of the basil oil were linalool (21.83%), estragole (74.29%), and α-humulene (2.17%), and those of the orange oil were α-pinene (0.54%), sabinene (0.38%), β-myrcene (1.98%), limonene (96.5%), and linalool (0.6%). As a toxic fumigant, the basil oil was more effective (24-h LC50=0.014 and 0.020mgcm-3) than the orange oil (24-h LC50=0.106 and 0.130mgcm-3) against S. zeamais and T. castaneum adults, respectively. Among the constituents of the two essential oils, the toxicity of estragole was the highest (0.004 and 0.013), followed by linalool (0.016 and 0.023), limonene (0.122 and 0.171), α-pinene (0.264 and 0.273), and β-myrcene (0.274 and 0.275) based on 24-h LC50 values (mgcm-3). Similar results were obtained in a contact toxicity test. The contact activity of basil oil was more toxic than orange oil, and estragole and linalool showed pronounced contact toxicity against S. zeamais and T. castaneum adults. Alpha-humulene had no activity as a fumigant at the tested doses, but it did have an effect as a contact poison, having 24-h LD50 values of 0.040 and 0.045mgadult-1 to S. zeamais and T. castaneum, respectively. Although basil oil, orange oil, and their components displayed both contact and fumigant toxicities, their effects were mainly exerted by fumigant action via the vapor phase. Thus, basil oil, orange oil, and their components could be potential candidates as new fumigants for the control of S. zeamais and T. castaneum adults. © 2013 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society.

Kim S.-I.,NaReSo Co. | Na Y.-E.,Korea Advanced Institute of Science and Technology | Yoon S.T.,Dankook University | Lee J.-K.,Korea Advanced Institute of Science and Technology | Oh Y.J.,Korea Biodiversity Research Center Co.
Nematology | Year: 2014

Nematicidal and hatching inhibition activities (HIA) of the methanol extracts from Dryobalanops aromatica (DA) and Mentha haplocalyx var. piperascens (MH), their constituents, and emulsified concentrate and granule formulations containing the methanol extracts as active ingredients, were compared with those of commercial nematicides, cadusafos and fosthiazate, against Meloidogyne incognita second-stage juveniles (J2) and eggs using well plate, container and pot assays. In a well plate assay with J2, DA applied at 500, 250 and 125 ppm resulted in 100, 95 and 55% mortality, respectively, while MH showed 80% mortality even at the lower concentration of 63 ppm. MH gave stronger HIA than DA at 1000 and 500 ppm. In addition, a-pinene, camphor, borneol and p-menthole, which are the main components of DA and MH extracts, showed strong nematicidal properties and HIA. In particular, the nematicidal activity of p-menthole among them was the highest and its HIA was also stronger than that of cadusafos and fosthiazate. In a container test using emulsifiable concentrate (EC) and granule (G) formulations containing 50 and 30% DA and MH, respectively, EC of D. aromatica showed a stronger LC50 value (0.203 μl (g soil)-1) than G formulation (0.935 mg (g soil)-1). However, their effects were fewer than MH formulations. The lethality of EC and G formulations containing MH was comparable to that of fosthiazate soluble concentrate and granule formulations. In another test using pots containing soils naturally infected by M. incognita, these plant formulations significantly inhibited the nematode-population density judging from the number of galls that formed on tested tomato roots after 8 weeks. These results suggest that DA and MH methanol extracts, as well as their constituents, might be useful as management agents against M. incognita. © Koninklijke Brill NV, Leiden, 2014.

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