This study was examined for activity of aggregation pheromone trap with residual effect of insecticides against Riptortus pedestris. Time of escape was from aggregation pheromone trap researched 49.74 min (ET99) and 65.01 min (ET99) with 1st and 2nd instar nymph respectively. Six insecticides for the stink bugs were treated to 3 different materials (wood, metal, and plastic). Bifenthrin and fenitrothion were showed 100% insecticidal activity at 48 h to all developmental stage of R. pedestris. Residual effect of bifenthrin and fenitrothion on plastic material were showed 100% insecticidal activity over 15 day after treatment with 1st, 3rd instar nymphs, and adults except 5th instars nymph. In field test using plastic material trap with two pesticides, 1st instar nymphs and adults were showed 100% mortality until 10 day after treatment. These results indicate that R. pedestris might be managed using aggregation pheromone trap with insecticides.

The effect of electron beam irradiation on development and reproduction of imidacloprid-resistant (R strain) and -susceptible (S strain) Aphis gossypii were compared. Nymphs and adults of R and S strain were irradiated at target doses of 50, 100, 150, and 200 Gy. When nymphs were irradiated, emergence was not affected at all target dose, but number of F1 nymph was perfectly inhibited at 150 Gy in both strains. When irradiated to the adults, longevity slightly decrease at 150 Gy and above. Fecundity was strongly decreased at 100 Gy, but was not completely inhibited even at 200 Gy. Emergence of F1 nymph was decreased at 100 Gy and completely inhibited at 200 Gy. However, there were no significant differences on development and reproduction of R and S strain. We also conducted the comet assay immediately after irradiation and over the following 10 day period. Severe DNA fragmentation in A. gossypii cells was observed just after irradiation and the damage was repaired during the post-irradiation period in a time-dependent manner. These results suggest that electron beam irradiation induced abnormal development, reproduction, and DNA damage in A. gossypii, but there were no significant differences between R and S strain.

A major concern in exporting agricultural commodities is the introduction or spread of exotic quarantine pests to the new area. To prevent spread of insect pests, various phytosanitary measures are used. In this study, we compared the effect of electron beam and X-ray irradiation on development and reproduction of the two-spotted spider mite, Tetranychus urticae. Eggs, nymphs, and adults were irradiated at target doses of 50, 70, 100, 150, 200, 250, and 300 Gy with electron beam and 10, 20, 30, 50, 70, 100, 150, and 200 with X-ray irradiation. When eggs were irradiated, egg hatching was completely inhibited at 150 Gy of electron beam and 50 Gy of X-ray irradiation. When irradiated to the nymphs, emergence was not affected at all target dose in both electron beam and X-ray irradiation. Hatchability of F1 generation was significantly decreased at 100 Gy of electron beam and 70 Gy of X-ray irradiation. When irradiated to the adults, longevity did not show any differences at all target dose in both electron beam and X-ray irradiation. These results suggest that the effect of X-ray irradiation was more potential than electron beam irradiation.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pests in various vegetable crops. In Korea, some field populations of A. gossypii especially in greenhouse showed high resistance against neonicotinoids. The imidaclopridresistant strain (IR) selected from one of the greenhouse strains was found to be about 3,800 folds more resistant to imidacloprid, compared to the susceptible strain (S), as judged by LC50 values. To identify differentially expressed genes in IR, an isogenic strain, reverse susceptible strain (IRS) was generated from IR and comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from both IR and IRS. Also we confirmed protein expression patterns by 2DE and detoxification enzyme over-expression by synergist test. However there was no significant variation among IR, IRS and S. Comparison of the nucleotide sequence of seven nicotinic acetylcholine receptor (nAChR) subunit (alpha 1-5,7 and beta 1) genes from S and IR strain revealed a point mutation causing an arginine to threonine substitution (R81T) in the loop D region of the nAChR beta 1 subunit of the IR. These mechanisms were also reported in M. persicae and this amino acid change confers a vertebrate-like character to the insect nAChR and results in reduced sensitivity to neonicotinoids. Moreover an extra point mutation, L80S (leucine to serine substitution) was also detected nearby R81T mutation in nAChR beta 1 subunit variant. These mutations can be an additive factor in imidacloprid resistance in A. gossypii. This is the first report of imidacloprid resistance mechanism in A.gossypii. Further, this would be helpful in managing A. gossypii resistant populations in field.

Fumigant effects of six plant essential oils (Helichrysum angustifolia, H. gymnocepha, H. splendidum, Arachis Hypogaea (peanut oil), Mentha arvensis (corn mint oil), and Thymus magnus (thyme oil) were tested against the adults of three grain storage insects (Lasioderma serricorne, Sitophilus zeamais, and Tribolium castaneum). Among them, the corn mint oil revealed to have fumigant toxicity against L. serricorne (LD50 = 1.3 ㎕ L-1), S. zeamais (LD50 = 3.6 ㎕ L-1), and T. castaneum (LD50 = 16.2 ㎕ L-1). The chemical constituents of corn mint oil were analyzed using GC-MS as follows: (-)-menthone (15.3%), isomenthone (10.0%), methyl-cetate (5.0%), β-caryophyllene (9.1%), and 1-menthol (48.1%). To enhance the fumigant toxicity, ethyl formate was added. This novel formulations of mixture could find significant differences in terms of their synergistic effects.

Termites are a major problem for home and business owners around the world. Termites gnaw through wood and burrow under the foundations of buildings causing a great deal of damage to the structure of the building. Phosphine (PH3) is very effective fumigant and is widely used to control pests. PH3 rapidly penetrate through treated material, so it replaced many conventional fumigants for treatment of durable materials. In this study, we have investigated the effectiveness of PH3 fumigation on wood pests, Reticulitermes speratus kyushuensis. We evaluated two bioassay methods; wooden cube (10×10×10 cm) and insect breeding dish in comparison with effectiveness of PH3 penetrations into the timber block. Fumigation to adults of R. speratus was carried in a desiccator system for 24 h at 5 and 15℃. As a result, LC99 of PH3 to R. speratus in wooden cubes and insect breeding dish at 5℃ was 0.183 and 0.177 mg L-1, respectively. LC99 of PH3 in wooden cubes and insect breeding dish at 15℃ was 0.077 and 0.078 mg L-1, respectively. There were no significant differences between the two bioassay methods. Thess results indicate that PH3 described herein merit further study as potential fumigants for termite control.

The cotton aphid, Aphis gossypii (Glover) (Hemiptera:Aphididae), is a highly polyphagous pest that directly or indirectly damages cultivated plants. Six field-collected populations of cotton aphid, A. gossypii (BY-A, BY-B, YJ-A, YJ-B, CJ-A, and CJ-B) were tested for susceptibility to 14 different insecticides. Most population exhibited high to very high levels of resistance to neonicotinoid. Among them, a strain showing resistance to imidacloprid were selected and showed 1,543-fold in resistance as compared with susceptible strain. Piperonyl butoxide (PBO), diethyl maleate (DEM), and S,S,S tributyl-phosphorothiolate (DEF) failed to synergize imidacloprid in this resistant population. In addition, the activity of detoxification enzymes (P450, EST, GST) were no differences between susceptibility and imidalcoprid resistance strain. However, by analyzing the nicotinic acetylcholine receptor β1 subunit loop D, R81T point mutation was detected in BY-A, BY-B, YJ-A, and YJ-B strain.

The effects of electron beam irradiation on life stage 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 completely 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 over 100 Gy. When irradiated to the adults, longevity and fecundity did not show any differences. However, egg hatching was significantly decreased at 100 Gy and above. Also, electron beam irradiation was not induced the rapid death of S. litura. Reciprocal crosses between irradiated and unirradiated moths demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. 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. The recovery of DNA damage in S. litura adults increased as time passed. but DNA damage hasn’t recovered fully. These results indicate that electron beam irradiation induced abnormal development and reproduction by DNA damage in S. litura. and as time goes by, the DNA damage was decresed.

Methyl bromide (MB) is a widely used fumigant in most of the countries for quarantine purpose. However, MB has been phasing out and under control in many countries because it is listed as an ozone-depleting substance under the Montreal Protocol. In this study, we have investigated the effectiveness of phosphine fumigation on wood pests for developing an MB alternatives. We evaluated two bioassay methods; wooden cube (10×10×10 cm) and normal fumigation procedures in comparison with effectiveness of phosphine (PH3) penetrations into the timber block. Fumigation to adults of Reticulitermes speratus was carried in a desiccator system for 24hr at 5 and 15 ℃. As a result, LC99 of PH3 to R. speratus in wooden cubes and insect breeding dish at 5℃ was 0.183 and 0.177 mg L-1, respectively. LC99 of PH3 in wooden cubes and insect breeding dish at 15℃ was 0.077 and 0.078 mg L-1, respectively.

The cotton aphid, Aphis gossypii Glover is an important sap-sucking pest of many pant, including cucumber and pepper. The objective of the present study was to determine the effects of sublethal concentrations of two insecticides (imidacloprid and flonicamid) and the action mechanisms on the feeding behavior of A. gossypii. The median lethal concentrations (LC50) of imidacloprid and flonicamid for adult A. gossypii were 2.01 and 1.92 ppm, respectively. The sublethal concentrations of imidacloprid were 0.22 ppm (LC10) and 0.82 ppm (LC30), and those of flonicamid were 0.094 ppm (LC10) and 0.56 ppm (LC30). The developmental period of A. gossypii nymphs at LC30 was 3.6 days for both insecticide which shorter than controls (4.2 days). Adult longevities at LC10 and LC30 of imidacloprid were 15.2 and 13.6 days, respectively. Adult longevity at LC10 and LC30 of flonicamid was 11.1 and 9.9 days, respectively. Control adult longevity was 15.5 days. Total fecundity was decreased at both sublethal concentration of two insecticides. Feeding behavior analysis using an electrical penetration graph showed that sublethal doses of imidacloprid and flonicamid had significant effects on the duration of phloem ingestion. However, higher doses of flonicamid induced starvation by inhibition of phloem ingestion and higher doses of imidacloprid induced contact toxicity rather than inhibition of feeding behavior.

The influence of electron beam irradiation on each developmental stage 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. Reciprocal crosses between irradiated and unirradiated moths demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. 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.

Insecticidal susceptibilities of 16 registered insecticides on each developmental stages of Phthorimaea operculella were investigated and further examined the contact, oral and residual toxicities after chosen from insecticides showing good effect. Mortality, longevity and effect on reproduction of 16 insecticides to P. operculella adults were also investigated. To the eggs and pupae, only spinosad showed 71.1% inhibition rate of egg hatch and 66.7% inhibition rate of emergence. To the 3rd nymphs, fenitrothion (LC50 336.6 ppm), esfenvalerate (LC50 8.6 ppm), ethofenprox (LC50 35.7 ppm), and emamectin benzoate (LC50 0.05 ppm) showed oral toxicity over 90% and esfenvalerate (LC50 0.87 ppm), ethofenprox (LC50 16.5 ppm), emamectin benzoate (LC50 0.53 ppm), and spinosad (LC50 2.48 ppm) showed the contact toxicity over 90%. To the adults, mortalities of insecticides were showed as below: deltamethrin and spinosad showed perfect mortality 48 h after treatment; esfenvalerate, ethofenprox, and thiamethoxam showed 40 - 60% mortalities; but the others are not showed any effect. Fecundities of female adults were inhibited by esfenvalerate, emamectin benzoate, and dinotefuran, compare to that of the control, but there were no statistical differences to that of ethofenprox, benfuracarb, thiamethoxam, clothianidin, and diflubenzuron. Adult longevity was showed no difference compare to that of the control. Residual effect of emamectin benzoate showed perfect insecticidal activity at 14 days after treatment and the next ethofenprox showed over 90% at 7 days after treatment.

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.

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.

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.

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.