• Korean journal of applied entomology
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• v.55 no.2
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• pp.139-148
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• 2016

A seasonal outlook for crop insect pests is most valuable when it provides accurate information for timely management decisions. In this study, we investigated probable tele-connections between climatic phenomena and pest infestations in Korea using a statistical method. A rice insect pest, brown planthopper (BPH), was selected because of its migration characteristics, which fits well with the concept of our statistical modelling - utilizing a long-term, multi-regional influence of selected climatic phenomena to predict a dominant biological event at certain time and place. Variables of the seasonal climate forecast from 10 climate models were used as a predictor, and annual infestation area for BPH as a predictand in the statistical analyses. The Moving Window Regression model showed high correlation between the national infestation trends of BPH in South Korea and selected tempo-spatial climatic variables along with its sequential migration path. Overall, the statistical models developed in this study showed a promising predictability for BPH infestation in Korea, although the dynamical relationships between the infestation and selected climatic phenomena need to be further elucidated.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.52-66
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• 1983

The brown planthopper, N. lugens (Stal), has become a serious pest of rice in tropical Asia during the last decade. At high pest density, its feeding damage causes 'hopperburn' or complete wilting and drying of the rice plant. It also transmits grassy and ragged stunt virus diseases. The estimated losses caused by the pest in tropical Asia exceed $US\$300$ millions. While cultivation of resistant rice varieties has proved to be highly effective against the pest, their long-term stability is threatened because of the evolution of prolific biotypes which can destroy these varieties. At present, identification of biotypes is based principally on the differential reactions of host rice varieties to the pest and on host-mediated behavioral and physiological responses of the pest. Recent findings of morphological differences in adult rostrum, legs, and antennae, body parts that possess receptors for host plant location and discrimination, and cytological differences in N. lugens populations maintained as stock cultures strongly complement other biotype studies. So far, three N. lugens biotypes have been identified in the Philippines. Biotype I can survive on and damage varieties that do not carry and genes for resistance, while Biotype 2 survives on resistant varieties carrying Bph 1 gene and Biotype 3 on varieties carrying gene bph 2. However, none of these biotypes can survive on varieties with genes Bph 3 or bph 4. Several varieties which are resistant in the Philippines are susceptible in India and Sri Lanka as the South Asian biotypes of N. lugens are more virulent than Southeast Asian biotypes. To monitor the pest biotypes in different geographical regions and to identify new sources of resistance, an International Brown Planthopper Nursery has been established in many cooperating countries. The evolution of biotypes is an exceedingly complex process which is governed by the interactions of genetic and biological factors of the pest populations and the genetic makeup of the cultivated varieties. While the strategy for sequential release of varieties with major resistance genes has been fairly successful so far, the monegenic resistance of these varieties makes them vulnerable to the development of the pest biotypes. Therefore, present breeding endeavors envisage utilizing both major and minor resistance genes for effective control of the pest.

• Korean journal of applied entomology
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• v.33 no.4
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• pp.270-280
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• 1994

This study was conducted to establish a nce insect pest control system, ~ es.ys tematic application of insecticides using carbohran and buproiezin, in Korea. The effects oi various dates of application and rates of buprofezin (25% WP) after carbofuran (3G) soil incorpombon in late May on the pop~~lation densities of the brown planthoppa (BPH) immigrating in July were investigated Appropriate application tune of buprofezin for the BPH that had evaded insecticidal effect of 5011 incorporated carbofuran was late July-early August. Application rate of buprofezln at 7.0g a.i/lOa was enough to suppress the BPH density. Buprofezin treatment after carbofumn soil incorporation could also suppress the whlte backed planthopper population but did not affect the densities oi the paddy rice spiders. Considering the charactenstics of occurring patterns of the nce insect pests in Korea. buprofezin treatment m late July or early August after carbofuran soil incorporation in late May can be a useful application system of ir~sectic~deins controlling early season Insect pests and migmtoly planthoppers on rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.105-110
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• 2010

This study was conducted to analyze the relationships between resistance of brown planthopper and traits related to the lodging in rice. For the linkage analysis of traits tested in this study, a genetic linkage map was created with 162 DNA markers spanning 12 rice chromosomes based on 120 doubled haploid (DH) lines, which were derived from a cross between Samgang', a Tongil type cultivar with BPH resistance, and ‘Nagdong’, a japonica cultivar. QTLs were identified to analyze the agronomic traits including lodging by composite interval mapping. Thirteen QTLs were detected for five traits comprised of plant length (PL), 3rd internode length (3rdIL), moments (Mo), lodging index (LI), and breaking weight (BW). The relationships between the BPH resistance and agronomic traits including lodging revealed that two QTLs (qBPR7, qBPR8) were linked to traits related to lodging. Two QTLs, qBPR7 and qBPR8 on chromosome 7 (RM531-7042) and 8 (RM1148- RM544) showed associations with moments and 3rd internode length, 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.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.236-243
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• 2009

This study was conducted to develop a japonica-type rice cultivar with brown planthopper (BPH) resistance using DNA markers. A doubled haploid (DH) population consisting of 120 pure-lines was established by anther culture of $F_1$ hybrids between 'Samgang', a Tongil type BPH resistance cultivar, and 'Nagdong', a japonica cultivar. To determine the map position of genes responsible for BPH resistance in rice, a genetic map was constructed based on 120 DH lines. A total of 162 molecular markers were classified into 12 linkage groups, covering 1,884 Kosami centimorgan (cM) with an average of 11.6 cM. Five QTLs (qBPR3, qBPR6, qBPR7, qBPR8, and qBPR12) associated with BPH resistance were identified and mapped on chromosomes 3, 6, 7, 8, and 12, respectively, using the genetic map constructed in this study. To analyze the relationship between BPH resistance and agronomic traits, a total of eight QTLs related to the agronomic traits were detected on 12 rice chromosomes. In an analysis of relationships, three QTLs (qBPR3, qBPR7, and qBPR8) showed a linkage with tested agronomic traits. A QTL (qBPR3) located on chromosome 3 (RM282-3023) was closely linked to culm length (qCL3). The QTL (qBPR8) for BPH resistance on the short arm of chromosome 8 also overlapped the region detected in culm length (qCL8).

• Research in Plant Disease
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• v.24 no.3
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• pp.202-212
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• 2018

Major viruses infecting rice are transmitted by planthoppers such as small brown planthopper (SBPH), brown planthopper (BPH) and white-backed planthopper (WBPH). In this study, we investigated planthoppers captured during 2015 to 2017 by a smart sky net trap (SSNT) system installed in 40 areas in Korea, which is an automatic, rapid and real-time insect surveillance system. The average rates of captured migration plnathoppers was 27.5%, 17.2%, 15.3% and 10.9% in Chungcheongnamdo, Jeollanamdo, Jeollabukdo and Gyeonggido, orderly. The highly migrated month was July for SBPH, July to August for WBPH and August for BPH. To investigate the viruliferous rates of planthoppers of rice during 2015 to 2017, we performed RT-PCR using specific primers for each rice virus. RBSDV was detected from 0.4% in SBPH, while no viruses were detected in BPH and SBPH. Rice planthoppers exist all around in Asia. They can move long distance by wind from southern countries to Korea. Monitoring the migration of rice planthoppers and their viruliferous rates is important to prevent the outbreaks of rice virus diseases.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.129-136
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• 2002

Agamermis unka, a mermithid parasite of brown planthopper (BPH), Nilaparvata lugens, is the most important natural enemy of BPH and white-backed planthopper (WBPH), Sogatella furcifera in Korea. Distribution of A. unka was investigated in Korean rice fields from 1992 to 1998 and in 2001. Overwintering population of A. unka in Gosung, Namhae, and Tongyoung from 1992 to 1998 was different depending on locality and year. In the survey of A. tanka distribution in the spring of 2001, A. unka was found only at Jangheung and Haenam in Jeonnam province and Namhae, Jinju, Sancheong, Sacheon, Gosung, Tongyoung, Uiryeong, Changwon, Gimhae, and the experimental field of Gyeongsangnamdo Agricultural Research and Extension Services at Jinju in Gyeongnam province out of 30 observed regions in 5 provinces. The number of A. unka was 1,045/㎥ at Namhae, 947/㎥ at the experimental field of Gyeongsangnamdo Agricultural Research and Extension Services, and 395/㎥ at Gosung. Density of A. unka at the rice paddies of Gyeongnam province after harvest in 2001 was higher at the rice fields of Namhae, Gosung, and the experimental field of Gyeongsangnamdo Agricultural Research and Extension Services. Although density of A. unka was higher in the pesticide-untreated plots than fungicide-treated or insecticide-treated plots of forecasting paddies, there were no significant differences. After rice harvest A. unka was found from the forecasting paddies of Gosung, Jinju, Namhae and Sacheon out of 19 observed localities in Gyeongnam province.

• Korean journal of applied entomology
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• v.22 no.2 s.55
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• pp.74-83
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• 1983

Yield losses due to diseases and insect pests were mentioned and emphasized the efficiency of resistant cultivars in curving the yield losses and increasing chemical efficiency. Present status of resistance breeding for blast, bacterial leaf blight viruses, brown planthopper and white backed planthopper were introduced and the resistance sources for those are discussed. Breeding strategies for above items were presented. Specially for the blast resistance, discussions were made in some detail. With brief future prospects of resistance breeding in Korea, a suggestion was made for pathologists to make clear about whether the blast spores will be brought from mainland China as we see with Bph and Wbph or not.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.262-270
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• 1983

The newly hatched nymphs of brown planthopper(BPH) were reared individually for two generations in test tubes, where young rice seedling was planted on agar solution, at $30^{\circ}C,\;25^{\circ}C\;and\;20^{\circ}C\;with\;95\%,\;75\%,\;65\%\;and\;35\%$ R.H. Effects of $30^{\circ}C$ on the development of BPH when compared with those of $25^{\circ}C$ are followings. Egg period, nymphal period, and adult longevity were shortened. Nymphal mortality was increased and the number of oviposited eggs was decreased. Hatchability was zero per cent because the eggs were either unfertilized or died before finishing the development. At the low temperature of $20^{\circ}C$, in comparision with $25^{\circ}C$, the developmental period of nymphs and eggs was considerably lengthened, and adult longevity was shortened, the number of oviposited eggs was decreased. The nymphal mortality was higher at high relative humidity $(above\;75\%\;RH)$ than that at low relative humidity $(under\;65\%\;RH)$. Under the condition of high relative humidities, the adult longevity was shortened, and the number of oviposited eggs was decreased.