• Korean journal of applied entomology
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• v.31 no.4
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• pp.475-479
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• 1992

The non-steroidal ecdysone agonist RH 5849 showed almost similar LC.o values( 18.1-26.5 ppm) at all stages of larval development of the tobacco cutworm, Spodoptera litura, when treated by a leaf-disk dipping method. The feeding-inhibition rate for the 4th instar larvae was dose-dependent, and simultaneously the weight gain of 3rd instar larvae ceased within 48 hour after feeding of the cabbage leafdisk dipped into RH 5849 4.2 ppm solution. The systemic larvicidal effect of RH 5849 was compared at cabbage and tobacco whole plant test. The $LC_{50}$ values below 20 ppm(mg/kg soil) was lasted for 15 days in cabbage, 30 days in tobacco respectively.

• Composites Research
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• v.20 no.2
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• pp.17-20
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• 2007

Superhydrophobic polytetrafluoroethylene ($Teflon^{(R)}$, Dupont) sub-micro and nanostructures were fabricated by the dipping method, based on anodization process in oxalic acid. The polymer sticking phenomenon during the replication creates the sub-microstructures on the negative polytetrafluoroethylene nanostructure replica. This process gives a hierarchical structure with nanostructures on sub-microstructures, which looks like the same structures as lotus leaf and enables commercialization. The diameter and the height of the replicated nano pillars were 40 nm and 40 um respectively. The aspect ratio is approximately 1000. The fabricated surface has a semi-permanent superhydrophobicity, the apparent contact angle of the polytetrafluoroethylene sub-micro and nanostructures is about $160^{\circ}$, and the sliding angle is less than $1^{\circ}$.

• Journal of the Korean Society of Tobacco Science
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• v.30 no.1
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• pp.1-7
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• 2008

Bacterial wilt caused by Ralstonia solanacearum has become a severe problem on tobacco in Korea. No effective single control measure is available at present time. One of the most potential way for controlling the bacterial wilt on tobacco is growing tobacco cultivars resistant to the bacterial wilt. In this study, optimal conditions for screening tobacco cultivars resistant to the bacterial wilt were examined to provide reproducible and efficient methods in growth chamber testing and field experiments for evaluating plant disease resistance. For this, already-known inoculation methods, inoculum densities, and incubation temperature, and plant growth stages at the time of inoculation were compared using tobacco cultivars resistant (Nicotiana tabacum cv, NC95), moderately resistant (N. tabacum cv. SPG70), and susceptible (N. tabacum BY4) to the bacterial disease. It was determined that root-dipping of tobacco seedlings at six true leaf stage into the bacterial suspension with inoculum level of $10^8$ colony-forming units (CFU)/ml for 20 min before transplanting was simple and most efficient in testing for resistance to the bacterial wilt of tobacco caused by R. solanacearum, for which disease incidences and severities were examined at 2 weeks of plant growth after inoculation at $20{\sim}25^{\circ}C$ in a growth chamber. These experimental conditions could discriminate one tobacco cultivar from the others by disease severity better than any other experimental conditions. In field testing, the optimum time for examining the disease occurrence was late June through early July. These results can be applied to establishing a technical manual for the screening of resistant tobacco cultivars against the bacterial wilt caused by R. solanacearum.

• Journal of Microbiology and Biotechnology
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• v.29 no.12
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• pp.1975-1981
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• 2019

Recently, outbreaks of food-borne diseases linked to fresh produce have been an emerging public health concern worldwide. Previous research has shown that when human pathogens co-exist with plant pathogens, they have improved growth and survival rates. In this study, we have assessed whether Escherichia coli O157:H7 benefits from the existence of a phytopathogenic bacterium and the underlying mechanisms were further investigated. When Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and E. coli O157:H7 were co-inoculated by either dipping or infiltration methods, the populations of E. coli O157:H7 increased; however, no effect was observed when type three secretion system (T3SS) mutants were used instead, suggesting that E. coli O157:H7 benefits from the presence of Pst DC3000. In addition, this study confirmed that the E. coli O157:H7 populations increased when they occupied the tomato leaf intercellular space; this colonization of the interior of the leaves was possible due to the suppression of the PAMP-triggered immunity (PTI) by Pst DC3000, in particular with the AvrPto effector. In conclusion, our data support a plausible model that E. coli O157:H7 benefits from the presence of Pst DC3000 via AvrPto suppression of the PTI resistance.

• Applied Biological Chemistry
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• v.37 no.6
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• pp.503-508
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• 1994

Methanol extracts from 45 species of oriental medicinal plants belonging to 17 families were subjected to a screening test for their larvicidal and antifeeding activities against two species of lepidopteran larvae, diamondback moth (Plutella xylostella L.) and tobacco cutworm (Spodoptera litura F.) by a leaf-dipping method. At a concentration of 8,000 ppm, methanol extract of Corydalis turrschaninovii roots only was found to have potent larvicidal activity against S. litura. At 5,000 ppm, strong antifeeding activity against both larvae was observed from the extracts of Clerodendron trichotomum, C. trichotomum var. esculentum, Inura helenium, Arctium lappa, Artemisia messerschmidtiana, Anthriscus sylvestris, Angelica dahurica, and C. turrschaninovii.

• Korean journal of applied entomology
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• v.20 no.4 s.49
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• pp.207-211
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• 1981

It has been documented that the resistance to planthoppers is attributed to the feeding preference of the insects. This might be related to difference in the amount of feeding plant sap between resistant and susceptible hosts. In this aspect, this study was conducted to verify it and to develop an effective screening method for resistance to planthoppers by tracer technique. An effective P-32 labelling of rice seedlings at $2\~3$ leaf stage was dipping the roots in concentration of $0.1{\mu}Ci/ml$ solution for 48 hours. Radioactivity was significantly higher in planthopers fed on susceptible variety for 48 hours as compared to those fed on resistant variety. Radioactivity of adults was higher than that of nymphs and also higher in female than male. The results were highly correlated to that indicated by the feeding preference of the insects and therefore, considered to be valid for a screening technique.

• 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.

• Korean journal of applied entomology
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• v.51 no.2
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• pp.149-152
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• 2012

The larvicidal activities of Piper nigrum fruit methanol extracts and its constituents against larvae of the diamondback moth, Plutella xylostella, were investigated using the leaf dipping method. Administering the P. nigrum methanol extract resulted in 100 and 97% mortality against diamondback moth larvae at 5.0 and 2.5 mg/mL concentrations, respectively. Larvicidal activities of the P. nigrum fruit-derived piperidine alkaloids, piperine, and N-isobutylamide, as well as pellitorine, guineensine, pipercide, and retrofractamide A against P. xylostella varied according to test compound. Based on the 48 h $LC_{50}$ values, the most toxic compound to diamondback moth larvae was guineensine (0.013 mg/mL) followed by retrofractamide A (0.020mg/mL), pipercide (0.033mg/mL), and pellitorine (0.046 mg/mL). The $LC_{50}$ value of piperine was >0.5 mg/mL.

• The Korean Journal of Pesticide Science
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• v.11 no.3
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• pp.194-200
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• 2007

Insecticidal activity of 33 registered insecticides was tested against last nymphal instars and adults of ussur brown katydid (Paratlanticus ussuriensis). All experiments were tested at the recommended concentration of each insecticides by producer. Acephate, chlorpyrifos, diazinon, EPN and fenitrothion which were organophates, and a mixture combined with chlorpyrifos+${\alpha}$-cypemethrin showed 100% mortality of P. ussuriensis. But fipronil showed only 100% mortality in leaf-dipping method. Carbamates insecticidal groups, benfuracarb and furathiocarb were showed over 80% and phenthoate was $60{\sim}80%$ in mortality of P. ussuriensis. Among the mixture, etofenprox+diazinon and esfenvalerate+fenitrothion were showed 60-80% against last nymphal instars of P. ussuriensis. Otherwise, acephate, chlorpyrifos, diazinon, EPN and fenitrothion were showed 100% mortality of P. ussuriensis within only 24 hours after treatment, but there was no effective after then in residual tests with leaves.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.451-454
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• 2020

Sericulture is a main insect industry in Sangju (Kyungpook, Korea). This study reports an occurrence of a viral disease in the sericulture farms in 2020. More than 20% silkworm larvae (Bombyx mori) suffered diarrhea and melted tissues with pathogenic lethality at 4th or 5th instars. PCR diagnosis showed a positive response against B. mori nucleopolyhedrosis virus (BmNPV) infection. Tissue extract of the infected larvae was applied to healthy larvae by a leaf-dipping method and exhibited the same viral symptoms. The viral extract was used to be overlaid on Sf9 cells. The infected Sf9 cells showed polyhedra in the cytoplasm. These results indicate that the silkworm larvae reared in the sericulture farms in Sangju were infected with BmNPV.