• Korean journal of applied entomology
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• v.47 no.1
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• pp.65-74
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• 2008

Methanol extracts of 35 plant species in 20 families were tested for their insecticidal activities and repellent effects against Nilaparvata lugens female adult by topical application and spray methods. The insecticidal activities and repellent effects of variousplant species and parts were different. The methanol extracts from stem of Garcinia xanthochymus, Senecio scandens and Phytolacca americana, seedcoat of Ginkgo biloba, and leaf+stem of Ailanthus altissima and Catalpa ovata showed potent insecticidal activities against N. lugens. Specially, the G. biloba extract exhibited higher than 90% mortality against N. lugens at a concentration of 4,000 ppm. Repellent effects of plant extracts obtained from whole plant of Daucus carota, fruit of Semecarpus anacardium, leaf+stem of C. ovata and Wisteria sinensis were active, and potent. Also, the plant extracts that are potent in insecticidal activity not necessarily have high repellent activity showing no significant corelation between the two activities.

• The Korean Journal of Pesticide Science
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• v.8 no.1
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• pp.16-21
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• 2004

A series of experiments was conducted to determine the toxicities of thiodicarb on the six lepidopterous pests (Pseudaletia separata, Plutella xylostella, Palpita indica, Spodoptera exigua, Helicoverpa assulta, Spodoptera litura) and to elucidate factors insecticidal effects mechanism of thiodicarb. Thiodicarb was very effective against six lepidopterous young larvae, but less effective to the old larvae and it acted slowly. Thiodicarb inhibited acetylcholinesterase and glutathione S-transferase activities, but not inhibit esterase activity.

• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.46-54
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• 2001

These studies were carried out to investigate the toxicities of 33 registered insecticide to the American serpentine leafminer, Liriomyza trifolii. Insecticidal activities were evaluated by testing systemic action and residual effect in the laboratory, and control efficacy and phytotoxicity in the greenhouse. All insecticides used in this study did not effect on the egg of L. trifolii, although spinosad showed 70% of egg-hatch suppression. For L. trifolii larvae ($2{\sim}3$ instar), the insecticides with over 95% of insecticidal activity were abamectin, cartap, cyromazine, emamectin benzoate, diflubenzuron + chlorpyrifos. The Insecticide what showed over 90% of insecticidal activity or neonate larvae were abamectin, cartap, emamectin benzoate, diflubenzuron + chlorpyrifos and milbemectin. Only cartap + buprofezin showed over 95% insecticidal activity against L. trifolii pupae. Almost insecticides used in this study little or not effected on the adult of L. trifolii. Emamectin benzoate and milbemectin showed moderate foliar systemic effects on eggs of L. trifolii (53.3, 47.9%, respectively). However, other insecticides showed little systemic effect. For larvae and adults, all insecticides showed low systemic effects. Insecticides with over 90% residual effect for 10 days were abamectin, emamectin benzoate and milbemectin (91.4, 90.4, 91.9%, respectively). In the control efficacy test on L. trifolii 90% of control values were obtained at 14th day after treatment of the insecticides including abamectin, cyromazine, emamectin benzoate and milbemectin. Cartap and cartap + buprofezin showed slight phytotoxicity on kidney bean leaf, however, other insecticides showed no phytotoxic effects. These results indicate that abamectin, emamectin benzoate and milbemectin can be used for tile control of L. trifolii in field.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.191-198
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• 2010

To predict and design of new potent insecticidal compounds, the two dimensional quantitative structure-activity relationships (2D-QSARs) and molecular hologram quantitative structure-activity relationships (HQSARs) between the various physicochemical parameters as descripters of N'-phenyl-N-methylformamidine analogues (1-22) and their insecticidal activity against the two spotted spider mite (Tetranychus urticae) were discussed quantitatively. From 2D-QSAR models (1 & 3), the width ($B_2$) of $R_3$-group as sterically factor and optimal total dipole moment (TDM=2.025D) of $R_4$-group were mainly influenced to increase the activity. Therefore, the activities were depend upon the $R_3$- and $R_4$-groups. Particularly, it is predicted that the activity of newly designed potent compound (PI; $EC_{50}$=0.516 ppm) by 2D-QSAR models (3) and HQSAR model F2 was about 34.3 fold higher than that of the commercialized insecticide, Amitraz ($EC_{50}$=17.7 ppm).

• 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.

• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.24-29
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• 2001

This study was conducted to investigate insecticidal activities of Ginkgo biloba (L.) leaves-derived bilobalide and its hydrolysis and oxidation products against adults of Nilaparavata lugens Stal. To find out active insecticidal moiety of bilobalide, decomposed intermediates and derivatives of bilobalide were made by hydrolysis, oxidation, and acetylation. The structures of hydrolysis product by base and oxidation product by acid were identified as cyclopentenone analogues and trilactone sesquiterpene from dehydration of bilobalide, respectively. Insecticidal activities of the decomposed intermediates and the derivatives of bilobalide decreased in the order of bilobalide, monoacetate, ginkgolide C, oxidation product, diacetate, and hydrolysis product. Therefore, trilactone structure of bilobalide may be essential for its insecticidal activity.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.67-71
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• 2000

Termiticidal activities of Chamaecyparis obtusa were quantitatively evaluated, and the activity differences between supporting materials such as woodmeal and filter paper or between species were defined based on the termiticidal activity value(TAV). It was found that TAV was high in the following order ; C. obtusa>Litsea coreana>C. obtusa var. formosensis>Ternstroemia gymnanthera. In particular, termiticidal activity of C. obtusa heartwood was stronger by 5 to 9 times than that of other three species. Median survival dosage(MSD) of C. obtusa was 108.8 mg. In case of woodmeal or filter paper tests with C. obtusa, termiticidal activities were inversely proportional to logarithms values of an added sample weight and median survival time(MST). The difference of termiticidal activities between woodmeal and filter paper in the methanol extracts was small, but that in the neutral fraction was enormous as 3.21 times. However, termiticidal activity of neutral fraction was corresponded to 17 to 53% of original woodmeal, and 47 to 83% of termiticidal activity was considered as a loss in test process.

• Research in Plant Disease
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• v.9 no.2
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• pp.99-103
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• 2003

Bioactivities of Korean ginkgo (Ginkgo biloba L.) extract were investigated against several fungi, general bacteria and insect pests. Crude methanolic extracts of different parts of Korean ginkgo showed different bioactivities depending on the target organisms. The methanolic extract showed in vitro antimicrobial activity at dose of 200 ug per paper disc. The extract of ginkgo stalk was some higher than seed coat and root. The extract also showed a remarkable in vivo antifungal activity against green mold (Trichoderma harzianum) on compost surface of spawn bags and in vivo insecticidal activity to Nilaparvata lugens, Plutella xylostella and Tetranychus urticae. This study suggests that Korean ginkgo extracts have a potential as a natural pesticide.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.200-205
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• 1995

Total 31 samples from 21 African plant species in 13 families were tested for their insecticidal and acaricidal activities against Nilaparvata lugens (Stal) and Tetranychus urticae (Koch) adults through topical application an leaf-dipping methods, respectively. The insecticidal and acaricidal activities were both plant parts and species dependent. The methanol extracts from whole plants of Casia occidental is and Cassia tora (Caesalpinaceae), an stem of Prosopis chinensis (Mimosaceae) revealed potent insecticidal activity against N. lugens. Potnet acaricidal activity against T. urticae was obtained from the methanol extracts from whole plants of Celosia trigyna (Amaranthaceae) and Combretum micronthum (Combretaceeae), leaves of Combretm glutinotum, and leaves and fruits of prosopis chinensis.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.166-176
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• 2011

Bacillus thuringiensis CAB530 was isolated from dead Anomata albopilosa (Rutelidae: Coleoptera) and soil of green tea field, and confirmed its insecticidal activities. CAB530 isolate showed a high insecticidal activity against the beet armyworm among the many lepidopteran insects that are difficult to control. $LC_{50}$ value of CAB530 isolate against the second larva of Spodoptera exigua was $1.49{times}10^4$ spore concentration (cfu/$m{\ell}$). SDS-PAGE result of insecticidal toxin protein of CAB530 isolate showed a band at 130 kDa that is similar pattern with B. thuringiensis subsp. kurstaki that took insecticidal activity against S. exigua. Otherwise, the crystal protein of the CAB530 isolate was conformed at 65 kDa level after 30 minute of incubation in S. exigua midgut juice. Six crystal genes (cry1Aa, cry1Ab, cry1C, cry1D, cry1F and cry1I) were identified by PCR. It different from genes of B. thuringiensis subsp. kurstaki. Crystal shape and pattern of toxin protein was similar with B. thuringiensis subsp. kurstaki, however, insecticidal activity and PCR result of CAB530 isolate was similar with B. thuringiensis subsp. aizawai.