This study was performed to evaluate the contact toxicity and residual toxicity of the 26 commercially registered insecticides against cigarette beetle, Lasioderma serricorne and maize weevil, Sitophilus zeamais adult. Among 26 insecticides, seven insecticides (chlorpyrifos, chlorpyrifos-methyl, fenitrothion, fenthion, phenthoate, cypermethrin, α-cyhalothrin) against L. serricorne adult and five insecticides (chlorpyrifos, chlorpyrifos-methyl, fenitrothion, fenthion, phenthoate) against S. zeamais adult showed perfect mortality. LC50 (ppm) values of those selected insecticides were appeared lowest value on α-cyhalothrin (1.46 ppm) against L. serricorne adult and chlorpyrifos-methyl (0.64 ppm) against S. zeamais adult, respectively. However, chlorpyrifos-methyl still remain high toxicity until 90th days after treatment against both L. serricorne and S. zeamais adults. From above results, it will be useful information to select insecticides effective against L. serricorne and S. zeamais adults.

The effects of electron beam irradiation on development and reproduction of Spodoptera litura were examined. Eggs, larvae, pupae, and adults were irradiated at target doses of 30, 50, 100, 150, 200, and 250 Gy. When eggs were irradiated with 100 Gy, egg hatching was perfectly inhibited. When irradiated to the larvae, pupation was inhibited at 100 Gy and larval period was delayed. When irradiated to the pupae, emergence was inhibited at 100 Gy and above. When irradiated to the adults, longevity and fecundity did not show any differences. However, egg hatching was strongly decreased at 100 Gy and above. Also, electron beam irradiation was not induced the instantaneous death of S. litura. The levels of DNA damage in S. litura adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage. These results suggest that electron beam irradiation induced abnormal development and reproduction by DNA damage in S. litura.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pest species devastating many horticultural, ornamental crops and fruit trees. Difficulty in managing this mite is largely attributed to its ability to develop resistance to many acaricides. Development of 3,700 folds resistance to etoxazole was found in the population of T. urticae collected from rose greenhouses in Buyeo, Chungnam Province in August 2000. This population has been selected for eleven years with etoxazole (over 500 times), and increased over 5,000,000 fold in resistance as compared with susceptible strain (S). Etoxazole-resistant strain was shown to be maternally inherited. The objective of this study was to determine whether resistance of T. urticae to etoxazole was linked with point mutations in the mitochondrial gene. DNA sequencing of cytochrome c oxidase subunit I (COX1), COX2, COX3, cytochrome b (CYTB), NADH dehydrogenase subunit 1 (ND1), ND2, ND3, ND4, ND5, and ND6 were analyzed by comparing two isogenic etoxazole-susceptible (EtoS) and etoxazole-resistant (EtoR) strains. As a result, all genes revealed no point mutations between the two strains.

The occurrence and rapid range expansion of a fulgorid, Lycorma delicatula(White), has recently been reported in korea. It was previously known to occur in China, Japan, Vietnam and India. The first occurrence fo L. delicatula was reported in 2004 in the Cheonan. It has one generation per year and overwinters as egg masses on the bark of host trees. The number of egg per egg mass was 32.69±6.49. The cumulative ratio of hatchability at different temperature was the highest at 25℃ and the lowest at 10, 30℃. The egg hatchability was investigated in different regions in Chung-buk. Since L. delicatula eggs has been stored in -20±1, 0±1, 5±1℃ conditions for 1 ∼60 days, the cumulative ratio of hatchability was 2% stored in -20±1℃ for 3days, But hatchability was 52, 48% stored in 0±1℃ for 3, 14days and 82, 68% stored in 5±1℃ for 3, 14days. And hatchability was 0% for 60days. By straight regression equation(the growth ratio/treatment degree) the growth zero degree of L. delicatula was 10.4℃. The hatchability of L. delicatula in Cheongwon-gun, Okcheon-gun, Cheongju-city where’s winter lowest temperature was over -19℃ was over 79%. But The hatchability of L. delicatula in Jincheon-gun where’s winter lowest temperature was less than -19℃(continuos two days) was 35%.

This study was investigated the seasonal occurrence of Metcalfe pruinosa (Say) in Chungbuk province and established the optimal control timing. Population densities of nymph and adults were investigated and egg hatching period and oviposition period was examined from three locations (Cheongwon, Jincheon, Eumseong area). Egg hatching period was investigated. The first day of egg hatching observed on May 25, the day of peak egg hatching was on May 29, and the perfect accumulative egg hatching ratio was on Jun. 13. Oviposition period of M. pruinosa female was observed the cut branch (cut within 10 cm length, 1 cm dia.) of oak tree, an althea, and an acacia under stereoscope. The first oviposition was observed at Jul. 28 and continually increased until late-Sept. with sharply increased at mid-Aug. Population density of M. pruinosa nymph was observed the cut branch (cut within 30 cm length, 1 cm dia.) of oak tree, an althea, an acacia, and pear tree. Population density began decreased showing after highest density with 25.3 (Jul. 1). The adult was first appeared at Jul. 11 and showed highest population density with 13.1 (Aug. 4) and then continuously decreased. To control M. pruinosa at pear orchard, optimal control timing for nymph was judged from Jun. 13 to Jul. 2, because of its small size of body and exuviae, low damaging by honeydew producing, low wax materials produced. Second control timing was judged at early Aug., when the adult invading to the pear orchard from near forest and the period before oviposition. The control agents for M. pruinosa were not yet registered, but will be anticipated to register the chemicals such as penitrothion WP, acetamiprid WP, dinotefuran WP, lambda cyhalothrin, thiamethoxam SP in 2012.

From April 2010 to the present, seasonal occurrence of Riptortus pedestris was investigated. Five locations for population density and migration route tracking were the same as last year (two sites of Mt. Yangseong, Jujung-dong, O-Chang, and the campus of Chungbuk National University(CBNU)). In Mt. Yangseong, separated the farmland (80m) and forest (200 and 300m) by altitude, population density in 2010 was showed high density at mid-June, mid-Aug., and late-Oct., but population density in 2011 was showed high density at late-April, late-July and mid-Aug. In O-Chang and Jujung-dong, population density in 2010 was captured the adult from June to Aug. in the farmland, and from Sept. to Nov. in the forest. Total captured number of R. pedestris were high in farmland than forest. In campus of CBNU, the adult was captured from mid-Jul. to late-Aug. It showed the difference in the population density by its environmental conditions. Attraction effect of pheromone lure trap with soybeans were good than that of pheromone lure trap only. To track the migration of R. pedestris, we painted the fluorescent paint with different color. Being painted 500 R. pedestris were released and recaptured 10 and 20 days after release. Among released 500 R. pedestris at asl 300m on Yangseong site A and B in 25 Apr. were recaptured one at 300 and 80 m at site A, and site B was recaptured one marked R. pedestris adult at 200 m. In 25 May, release at 200 m in site A was recaptured only 80 m with 2 and site B was recaptured 200m with 8 and 80m with 1. Released in 17 Jul. at 80 m, marked R. pedestris adults were recaptured only 80 m with 5 and 2, respectively. It means that R. pedestris adults seem to migrate from the forest to the farmland in this season, but the data from Aug. to Oct. in 2010 was different.

This study was performed to investigate the effect of flonicamid and thiamethoxam treated at sublethal concentration (LC10, LC30) on development period, adult longevity and fecundity and the feeding behaviour of Myzus persicae adult. Developmental period of M. Persicae nymph took 5.9 days in LC10, and 6.1 days in LC30 in both insecticides, comparing with control (5.7 days), it showed longer than those of the control, but there was no significance. Adult longevity treated at LC10 and LC30 of flonicamid was showed 13.2 and 13.7 days, respectively, and LC10 of thiamethoxam was examined as 14.7 days, it showed longer than control of 11.6 days. Mean daily fecundity exhibited higher in LC10 (3.1) and LC30 (3.1) of flonicamid than that of control (2.5), but thiamethoxam are not. Total fecundity exhibited higher in LC10 (41.8) and LC30 (43.0) of flonicamid, in LC10 (42.1) of thiamethoxam than that of control (29.5). Feeding behavior was examined using EPG (electrical penetration graph). EPG data indicated that flonicamid and thiamethoxam increased the duration of non-probing periods and decreased the duration of phloem ingestion.

From the methanol crude extracts of the tree of heaven (Ailanthus altissima) leaves, the antifeedant substance was isolated and bioassayed with different concentrations against diamondback moth (Plutella xylostella) larvae. The antifeeding activity was evaluated by measuring the feeding area during 24 hr after inoculation. Methanol extracts showing antifeeding activity at 5000 ppm was subsequently fractionated into hexane, chloroform, ethyl acetate and water layer. Third larvae of diamondback moth was tested to each fraction layer. Chloroform layer shows the highest antifeeding activity and the layer was purified by silica gel open column chromatography. The C22 and C23 fractions showed higher antifeeding ratio with 96 and 86%, respectively, and then these two fractions were re-isolated by ODS open column chromatography. As a result, both fractions in methanol 40% (v/v) showed antifeeding ratio over 90%. The C221 fraction showed insecticidal activity in all fraction, however, C231 fraction was showed the antifeeding activity only in C2311 fraction. The C2311 fraction judging to have antifeeding activity was re-isolated and purified by HPLC and recycling, and finally obtained the bioactive substances (C23111) with antifeeding ratio with 88%. The structure of bioactive materials isolated was confirmed by LC-mass and 1H-NMR(500 MHz), 13C-NMR(100 MHz).

The repellency, insecticidal activity and repellency duration effect of dagalet thyme, Thymus quinquescostatus against Asian tiger mosquito, Aedes albopictus larvae and adults was investigated. Whole plant body of T. quinquescostatus proved to have the repellent activity of 91.2% against A. albopictus adults. The constituents of T. quinquescostatus were analyzed using GC-MS as follows: α -pinene (1.1%), α-thujene (2.7%), camphene (1.3%), myrcene (4.7%), α-terpinene (5.0%), ɤ-terpinene (33.0%), ρ-cymene (8.3%), β-caryophyllene (4.0%), β-bisabolene (8.9%), thymol (29.9%), and carvacrol (1.2%). Among them, thymol has the perfect repellency on A. albopictus adults and confirmed the electrophysiological response on the antenna of A. albopictus adults. To enhance the maintenance, vanillin was added. Duration of effectiveness of mixture with vanillin (0.18 : 0.36 ㎕/㎠) were significantly more prolonged than thymol alone. The constituents on its original oils were applied onto A. albopictus larvae. The thymol, α-terpinene and carvacrol (LC50 = 9 mg litre-1) revealed to have high insecticidal activity.

The American serpentine leafminer fly, Liriomyza trifolii (Burgess), is one of the most destructive polyphagous pests world wide. In this study, we determined electron beam doses for inhibition of normal development of the L. trifolii and investigated the effect of electron beam irradiation on DNA damage and p53 stability. Eggs, larvae, pupae and adults were irradiated with increasing doses of electron beam irradiation (six levels ranges from 30 to 200 Gy). At 150 Gy, the number of adults that developed from irradiated eggs, larvae and pupae was lower than those of untreated control. Fecundity and egg hatchability decreased depending on the doses applied. Reciprocal crosses between irradiated and unirradiated flies demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. The levels of DNA damage in L. trifolii adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage in a dose-dependent manner. Moreover, low doses of electron beam irradiation led to the rapid appearance of p53 protein with in 6 h; however, it decreased after exposure to high doses (150 Gy and 200 Gy). These results suggest that electron beam irradiation induced not only abnormal development and reproduction but also p53 stability caused by DNA damage in L. trifolii. We conclude that a minimum dose of 150 Gy should be sufficient for sterilization of L. trifolii.

In this study, we compared global proteome profiles and the expression pattern of defense-related genes in Chinese cabbage when infested by Myzus persicae and Plutella xylostella. Four-week-old Chinese cabbage was exposed to each insect for 24 h, and then proteins and total RNA were extracted from leaves. To elucidate the herbivore-induced differentially expressed proteins in Chinese cabbage, proteins were separated by two-dimensional gel electrophoresis, and visualized by staining with Coomassie G250. Approximately 1600 protein spots were separated and 249 protein spots showed reproducible changes in expression. Among them, nine proteins whose expressions were markedly up-regulated in M. persicae-infested group were identified using matrixassisted laser desorption/ionization time of flight mass spectrometry. The identified herbivore-responsive proteins (ribulose-1,5-bisphosphate carboxylase/ oxygenase, ATP synthase CF1, putative mismatch binding protein Mus3, and integrase core domain-containing protein) were involved in regulation of photosynthesis, carbohydrate metabolism and DNA repair. The expression levels of chitinase, b-1,3-glucanse, peroxidase, PR1, and PR4 in herbivore-infested Chinese cabbage were analyzed by reverse transcription-polymerase chain reaction. The results clarify the response of Chinese cabbage to two herbivore attack at the protein level.

This study was performed to investigate the antifeeding activity of Perilla frutescens extracts against diamondback moth, Plutella xylostella larvae and to confirm the electrophysiological responses of two sensilla (LST=lateral styloconic sensillum, MST=medial styloconic sensillum) in maxilla galea, a chemoreceptor. Crude extract of P. frutescens in methanol was showed antifeeding activity approximately 70%, and subsequently separated into four fractions - n-hexane(H), chloroform(C), ethylacetate(E), and water(W). Antifeeding activity was only showed in n-Hexane fraction around 99%. H1, H2, H3, H4, H5 were isolated from n-Hexane fraction using an open column chromatography, and the bioassay showed strongest antifeeding activity in H1 fraction. Using an oscilloscope, electrophysiological responses of two sensilla showed more seven times activity in MST. H11, H12, H13, H14 were separated from H1 fraction and antifeeding activity was showed highest in H11 fraction. H11 fraction was examined electrophysiological responses at doses of 100, 10, and 1 ppm, and MST of P. xylostella responded at a dose of 100 ppm. H11 fraction was separated using HPLC and identified using GC/MS and NMR. Finally, the structure of active compound proved to be farnesene with molecular weight of 204, and a formula of C15H24

The purpose of this work was to study the effects of electron beam irradiation on development and reproduction and evaluate the DNA damage in Plutella xylostella. Adults and pupae of P. xylostella were irradiated with 30, 50 and 100 Gy electron beam. Hatchability and fecundity of adults declined as increased irradiation doses. When pupae were irradiated with 100 Gy, fecundity of emerged adults significantly decreased and no eggs hatched. However, the adults longevity and emergence of pupae did not change. Assessment of DNA damage in cells obtained from adults and pupae of P. xylostella was carried out using single-cell electrophoresis (comet assay). Electron beam-radiated adults and pupae showed that tail length and percentage of DNA damage at all the doses were significantly larger than the control batch. Our results suggest that electron beam induces sterility through the DNA damage and this technique could contribute to analytical identification of an effective disinfestation and quarantine treatment.

This study was performed to investigate attraction effect of spearmint oil and to confirm their EAG response against lantern fly, Lycorma delicatula nymphs and adult. In dose responses to spearmint oil, 2nd ∼ 4th nymphs and adult were significantly attracted at a dose of 5㎕. Attraction effect was showed highest (84.8%) at a 4th instar nymph, and mild effect (approximately 60%) was observed at 2nd∼3rd instar nymphs, but the others are not showed the significance. At a dose of 10㎕, 4th instar nymph and adult were significant and only 4th instar nymph was significantly attracted at a dose of 2.5㎕ but the others are not. Carvone, a constituent of spearmint oil, exhibited significantly attraction effect on nymphs and adult except 1st and 2nd instar nymphs. But limonene did not show any attraction effect. The attraction assay of L. delicatula to the mixtures of constituents appeared to be efficient additively. In EAG response to spearmint oil which exhibited attraction effect, antennae of 4th instar nymph and adult responded to only carvone. In conclusion, attraction effect of spearmint oil was more effective in 4th instar nymph and adult than 1st ∼ 3rd instar nymphs.

Cuticular hydrocarbons (CHCs) were analyzed using GC and GC-MS, and compared with developmental stages of the Lycorma delicatula. Total Carbon numbers on all developmental stages are 21-36, and composition numbers are 51. On the whole, Carbon numbers increased as passed times on developmental stages. Except for eggs, Lycorma delicatula consisted of n-heptacosane on almost all developmental stages, and followed by n-nonacosane. Eggs, however, consisted of 9-; 11-; 13- methylheptacosane. From the above results, CHCs on developmental stages of the Lycorma delicatula consisted of n-alkane with saturated hydrocarbons (36%), followed mono- (34%) or di- (21%) methylalkanes. Above this, CHCs consisted of tri- methylalkanes (3.9%) and olefines (2.3%) that have double bond. The major constituents of CHCs on the developmental stages of Lycorma delicatula is differently proportioned, but hardly showed the difference in their composition.

On the development and reproduction of four major agricultural insect pests including B. tabaci, M. persicae, P. xylostella and T. urticae, electron-beam was irradiated with different doses of 30, 50, 70, and 100 Gy. The effect of electron beam was investigated with respect to the longevity, egg hatching, emergence, and fecundity. Eggs hatching of B. tabaci, P. xylostella and T. urticae were more inhibited as increased irradiation doses. Especially B. tabaci and T. urticae eggs were perfectly inhibited to hatch at a dose of 100 Gy. However, these pests showed no lethal effect on the nymph/larva, pupa, and adult stages. When irradiated on the eggs of B. tabaci, P. xylostella and T. urticae, the emergence was inhibited from nymphs/larvae to adults. Individually, B. tabaci emerged adult did not lay eggs at a dose of 70 Gy. Besides, fecundity of P. xylostella emerged adult decreased at a dose of 100 Gy. On the contrary, irradiation did not affect the longevity of P. xylostella adult. When irradiated on B. tabaci, P. xylostella, Myzus persicae and T. urticae nymphs/larvae, emergence was inhibited at doses of 70 and 100 Gy, and decreased the fecundity and inhibited the hatching of laid eggs. However, the longevity of adults did not affect

This study was performed to investigate attraction effect of six plant essential oils and to confirm their electrophysiological response against Lycorma delicatula. Among the tested oils, spearmint oil (94.1%) significantly attracted L. delicatula at a dose of 1.25㎕/cm2 by using an olfactometer. In dose response to spearmint oil, a dose of 2.5㎕/cm2 was very effective. GC-MS analysis revealed that the active components responsible for the effective attraction effect of spearmint oil were carvone (70.6%) and limonene (54.8%). Of the two active components, carvone was more significant than limonene with reference to attraction activity against L. delicatula. Analysis by GC-EAD showed, major components of spearmint oil that elicited response in L. delicatula antennae, indicating the potential role of the essential oil as attractant that determine the choice of the attraction material. In the field test, spearmint oil exhibited attraction effect up to 5 days. This effect was different in accordance with test places and treatment dose.

Twospotted spider mite, Tetranychus urticae was collected from the rose greenhouse in Gimhae, Gyeongnam province in Jan, 2001. Resistant strain was reared over nine years treated with Acequinocyl (over 400 times), and increased 614 folds as compared to susceptible strain (S). Cross resistance of acequinocylresistant strain adults to eight acaricide was showed high in Cyflumetofen (108 folds) and expressed low in Abamectin (16 folds), Tebufenpyrad (7.6 folds), Fenpyroximate (6.1 folds). Against Chlorfenapyr (0.5 folds), however, showed negatively correlated cross resistance. Synergistic effects with PBO (piperonyl butoxide), an oxygenase inhibitor, DEF (S,S,S-tributyl phosphorotrithioate), an esterase inhibitor, and DEM (diethymaleate), an inhibitor of glutathion S-transferase were also investigated. Synergistic effect showed low in DEM (4.2 folds) but showed high in PBO (12 folds) and DEF (23 folds).

Insect pest may move to near area to forage the food by adverse changes of their environments. Understanding these behaviors of searching the host will be helpful for further control. This study was performed to investigate the host preference and distribution of B. tabaci in a host plant when they needs. Once entered an area including hosts, B. tabaci will select a host rather than non-host and stayed for living. Dispersal within a niche (in a whole plant), B. tabaci was observed in lower part in tobacco and middle in tomato when seedlings, but they dispersed throughout the whole fully grown tomato plants with irregular inclined to the under, outer stretched leaves. Bemisia tabaci was also caught massively in yellow sticky traps in height of 30 cm above soil, and 30 cm above a plant. There was no attraction effect by flower model traps and fly catcher. When introduced with different densities (0, 10, 50, 100, 200, and 400) in square cages, the B. tabaci do damaged at the densities of 200 with mild and 400 with severe symptom on plants in two weeks and four weeks after inoculation.

Economic injury level was estimated for the sweetpotato whitefly, Bemisia tabaci on greenhouse tomato (Lycopersicon esculantum cultivar pinktop). In the greenhouse, seedling tomato transplanted at mid-April and inoculated B. tabaci at late-April with the densities of 0, 1, 3, 9, 27, 54, 108 and 216 per plant. Only 108 and 216 inoculation densities increased until mid-July. Total weight of fruits was not showed the differences by initial whitefly density; however, the total weight of marketable fruits decreased significantly among plots by higher initial whitefly density. The rates of yield loss increased with increasing whitefly density, resulting in 8.3, 14.0, 29.7, 29.7, 25.7, 40.4, and 69.4% reduction in each of the plots, respectively. The relationship between initial whitefly densities and yield losses was well described by a linear regression, Y= 18.09X+6026.5, R2=0.8504. Based on the relationship, the number of adults per plant which can cause 5% loss of yield was estimated to be approximately 17.