• The Korean Journal of Pesticide Science
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• v.2 no.1
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• pp.24-31
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• 1998

Chemical derivative synthesis of ricinine, an active compound of Ricinus communis which showed high mortality against brown planthopper (Nilaparvata lugens), was performed to improve its pesticidal activity and the toxicity of 12 synthetic derivatives against major insect pests and phytopathogenic fungi were examined. Carbamate derivatives of ricinine could be synthesized from the precursor of ricinine, chloronorricinine and norricinine, whereas the derivatives were not synthesized from chlororicinic acid and ricinic acid having ketone group of pyridine ring. In organophosphates, reaction with oxon type of phosphate gave better yield than thiono type. Among the organophosphate derivatives of ricinine, thiono type of derivative structure gave $96.3%{\sim}100%$ mortality of the brown planthopper and the two-spotted spider mite (Tetranychus urticae) at 500 ${\mu}g/ml$ level. On the other hand, carbamate derivatives did not show insecticidal activity. In the fungicidal activity of ricinine derivatives, the derivative having amino radical at the 2 position of ricinine gave 85 to 100% of mycelium growth inhibition effect against ten major plant pathogens at the 200 ${\mu}g/ml$ level. In particular, the control value of the derivative on the rice blast (Pyricularia grisea) and barley powdery mildew (Erysiphe graminis) at the 250 ${\mu}g/ml$ level in vivo under greenhouse conditions was 92% and 96%, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.453-456
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• 2005

This study was carried out to select DNA markers closely linked to brown planthopper (BPH) resistance gene originated from a rice cultivar 'Cheongcheong­byeo'. For the mapping of resistant gene to BPH, a doubled-haploid (DH) population was developed by anther culture of $F_1$ plants from a cross 'Cheongcheong­byeo/Nagdongbyeo'. In BPH bioassay and marker screen­ing for the DH population, the segregation of resistant and susceptible plants to BPH fitted to a 1:1 ratio. A total of 310 RAPDs of 520 markers showed polymorphism in parental survey using 'Cheongcheongbyeo' and 'Nag­dongbyeo'. In the analysis of relationship between BPH resistance and marker pattern for 40 DH lines, the OPE16 produced a specific dominant fragment, 700 bp, which was closely linked with BPH resistance gene of 'Cheong­cheongbyeo'. Based on the linkage analysis using 7 markers, BPH resistance of 'Cheongcheongbyeo' was mapped on chromosome 12, which was closely linked with $OPE16_{700}$ at a distance of 4.6 cM.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.90-95
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• 1986

A comparative study of chemical characteristics, efficacy and relative merits of extruded and coated granules, containing fungicide and insecticide, was conducted under laboratory and field conditions. Probenzole (3-allyloxy-1,2-benzisothiazole 1,1-dioxide) and carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranyl methyl carbamate) were chosen as toxicants for rice blast(Pyricularia oryzae) and brown planthopper (Nilaparvata lugens) control, respectively. Stability of active ingredients in coated granule was superior to the extruded one under accelerated temperature. Active ingredient dissolution of coated one into distilled water showed slow release pattern. Pesticide residues in rice (Oryzae sativa, Chucheongbyeo) shoot applied with extruded one at the dosage of 3kg/10a retained higher levels than those with coated one on two days after application, while the residue levels were a reversed tendency on eight days after application. Efficacy on rice blast exhibited minute differences between the granules, on the other hand efficacy on brown planthopper by coated one was of higher rank than that by extruded one. Production cost of the combined pesticide granule by coating method could be cut down by 6% as compared to extrusion method.

• Journal of Microbiology and Biotechnology
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• v.28 no.6
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• pp.976-986
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• 2018

Knowledge about the gut bacterial communities associated with insects is essential to understand their roles in the physiology of the host. In the present study, the gut bacterial communities of a laboratory-reared insecticide-susceptible (IS), and a field-collected insecticide-resistant (IR) population of a major rice pest, the brown planthopper Nilaparvata lugens, were evaluated. The deep-sequencing analysis of the V3 hypervariable region of the 16S rRNA gene was performed using Illumina and the sequence data were processed using QIIME. The toxicological bioassays showed that compared with the IS population, IR population exhibited 7.9-, 6.7-, 14.8-, and 18.7-fold resistance to acephate, imidacloprid, thiamethoxam, and buprofezin, respectively. The analysis of the alpha diversity indicated a higher bacterial diversity and richness associated with the IR population. The dominant phylum in the IS population was Proteobacteria (99.86%), whereas the IR population consisted of Firmicutes (46.06%), followed by Bacteroidetes (30.8%) and Proteobacteria (15.49%). Morganella, Weissella, and Enterococcus were among the genera shared between the two populations and might form the core bacteria associated with N. lugens. The taxonomic-to-phenotypic mapping revealed the presence of ammonia oxidizers, nitrogen fixers, sulfur oxidizers and reducers, xylan degraders, and aromatic hydrocarbon degraders in the metagenome of N. lugens. Interestingly, the IR population was found to be enriched with bacteria involved in detoxification functions. The results obtained in this study provide a basis for future studies elucidating the roles of the gut bacteria in the insecticide resistance-associated symbiotic relationship and on the design of novel strategies for the management of N. lugens.

• Korean journal of applied entomology
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• v.13 no.1 s.18
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• pp.11-16
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• 1974

Experiment was conducted to select the rice varieties and lines resistant to the smaller brown planthopper, Laodelphax striatellus Fallen, and study the cause of varietal resistance to the insect. The nature of varietal resistance was evaluated from the viewpoints of feeding and ovipositional preferences and antibiosis. Among the IRRI sources the varieties H 105, Muthumanikam, Vellailangalayan, Karsamba Red ASD-7. Manavari Co 22, Mudgo, PTB-18, IR 8 and IR 20 were selected as resistant sources. Among the domestic sources. only Suweon 213-1, Suweon 214 and Suweon 215 originated from the IR667 lines were resistant, and other leading varieties ail susceptible. The cause of resistance of rice to the insect seemed to be highly related with the non-feeding preference, not non-ovipositional preference. Nymphal mortality and rate of adult emergence were significantly different from the resistant and susceptible varieties. The rate of adult emergence was significantly lower in the resistant than In the susceptible varieties. The primary cause of lower adult emergence seemed to be due to the fact that the infects were suffered higher nymphal mortality in the resistant than in the susceptible varieties.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.351-358
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• 2016

Consistent with a previous study on the brown planthopper Nilaparvata lugens (BPH) (Seo et al., 2009), we identified seven distinct EPG waveforms (np, L1, L2, L3, L4-a, L4-b, and L5) in adult female Laodelphax striatellus (SBPH) that fed on rice plants, by using the direct current electrical penetration graph (DC-EPG) system. The shape of waveforms and the pattern of occurrence of each waveform of SBPH were very similar to those of BPH. L3 and L4-a always occurred prior to L4-b. Periodical honeydew excretion was observed in L4-b only. Microsection observation following laser stylectomy revealed that the tips of SBPH stylets severed in L3, L4-a, and L4-b were commonly located in or near the phloem region of rice plants, but were located in the xylem in L5. Plant sap flowed from the stylets severed in L4-b only, and its main carbohydrate component was detected as sucrose by HPLC analysis. These results and the patterns of EPG waveform progress in SBPH suggested that feeding activities on rice plant tissue were relevant to each EPG waveform. L1 and L2 corresponded to the initiation of stylet penetration and stylet movement with salivation on the outside of the vascular bundle. L3 and L4-a were related to feeding activities within the phloem region in preparation for phloem sap ingestion. L4-b was closely associated with phloem sap ingestion, and L5 corresponded to xylem feeding behavior.

• Korean journal of applied entomology
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• v.27 no.4
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• pp.200-210
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• 1988

ABSTRACT Brown planthopper collection data by 151 light traps located throughout the southern part of Korean peninsula for 7 years from 1981 thru 1987 were analysed with each immigration wave in relation to daily weather charts when the immigration occurred, and summarized as below. 1) Most of the main immigration took place during the mid and late July, though there were some variations from year to year. 2) Number of the BPH collected at one time, and the number of the area where those immigrants where collected were increased when it occurred closer to the end of July. 3) Weather conditions when the immigration took place were divided into 4 types; (a) depression with stationary front passed over the central peninsula (A type, 12 times); (b) depression with stationary front passed over the southern sea (B type, 5 times); (c) stationary front passed over the central peninsula(C type, 7 times); (d) without depression and stationary front (D type, 2 times). 4) Whatever the types of the weather, those immigrations started to land from south-west part of the peninsula, and those numbers of immigrants were also grater at those south-western areas. 5) When common weather factors were counted from each weather chart of the days when thcse immigrations took place, presence of wind from south-west was 26 times, presence of stationary front was 24 times, and presence of depression was 17 times out of all 26 cases of immigration. 6) Therefore, it could be concluded that the immigration of the BPH into Korea is simply accompanied by the north$.$easterly flowing air currents, connected from south-east part of China through Korean peninsula. And other factors seem to be related with inducing their landing.anding.

• Korean journal of applied entomology
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• v.27 no.2
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• pp.87-93
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• 1988

Some attempts were made to investigate the biological characteristics of the brown planthopper(BPH), Nilaparvata lugens St${\aa}$l, biotypes in terms of perference in feeding oviposition on rice field, egg and nymphal periods, egg hatchability, emergemce ratio, growth index, adult lingevity and gecundity fed on 60-day-old rece cultivaes with different resistance genes. Feeding and oviposition perference of the three BPH biotypes on Dongjinbyeo with no resistance gene were shown very higher than on rice cultivars with resistance genes. Those of biotype-2 on Cheongcheongbyeo with bph 1 gene and bitype-3 on Milyang 63 with bph 2 gene were relatively high, however, they were still remarkably lower than those of Dongjibyeo. The egg and nymphal periods of the three BPH biotyes on Milyang 23 were shorter than on the other rice cultivars. The periods of biotype-2 on Cheongcheongbyeo and biotype-3 on Milyang 63 were as short as those of the three BPH biotypes on Milyang 23. The egg hachability, emergence ratio, and growth index of the three BPH bioyoes on Milyang 23 were higher than on the other rice cultivars and those of biotype-2 on Cheongcheongbyeo and biotyoe-3 on Milyang 63 were as high as on Milyang 23. The female adult longevity of the BPH biotype-1 on Milyang 23 was longer than on the other cultivaes, and that of biotype-2 on Cheongcheongbyeo and bioty-3 an Milyang 63 were as ling as on Milyang 23. The number of egg laid by a female of the three BPH biotypes were greatly increased on Milyang 23. Those of biotype-2 on Cheongcheongbyeo and biotype-3 an Milyang 63 were also greatly increased.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.419-423
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• 2015

Small brown planthopper (SBPH), Laodelphax striatellus, gives a lot of damage to the rice by insect vector of rice stripe virus (RSV). This study compared the RSV acquisition and infection rates according to wing form, sex, and life stage of SBPH. The RSV acquisition rate in macropterous and brachypterous was 60.7% and 63.1%, respectively. The RSV acquisition rate by sex was 61.9% in female and 52.2% in male. However, there was no difference in significance. The RSV acquisition rate of nymphs and adults was 51.2% and 58.7%, respectively. The RSV infection rate by wing form was 53.3.% in macropterous and 48.2% in brachypterous. According to life stage, nymphs was 38.2% and adults was 42.6%. There was no difference in significance. On the other hand, female and male of RSV infection rate was 50.5% and 22.3%, respectively. There was a significant difference. Additionally, developmental periods of SBPH by RSV infection, the longest when inoculated with RSV-infected SBPH in healthy rice, while the shortest when inoculated healthy SBPH in healthy rice.

• Korean journal of applied entomology
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• v.56 no.4
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• pp.351-356
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• 2017

For determining the insecticidal effect of Carbofuran on the Brown planthopper, Nilaparvata lugens, sucking toxicity by drenching application, sucking and contact toxicity by leaf dipping application, and contact toxicity by topical application were examined. Drenching caused two types of mortality patterns. One was logarithmic curve at a relatively high concentration (8~30 ppm) with over 40% mortality in 24 h, and the other was an S-shaped curve at low concentrations (1~4 ppm) with over 60% mortality on the fifth day after Carbofuran treatment. Leaf dipping application caused a rapid increase in mortality in a day, and this effect decreased steadily with time. Topical application showed steep increase in mortality in a day, and hardly increased thereafter. The best mortality evaluation time for the drenching application was the second day (42 h), and that for the leaf dipping and topical applications was the first or second day after Carbofuran application. When the insecticide has systemic effects, drench application provides the best efficacy and its insecticidal effects persist for a longer time than any other application method.