• Korean journal of applied entomology
• /
• v.42 no.4
• /
• pp.361-365
• /
• 2003

Several species of planthoppers such as brown planthopper, N. lugens (Stal) (BPH), smaller brown planthopper, Laodelphax striatellus (Fall n) (SBPH), and white-backed planthopper, Sogatella furcifera (Horv th) (WBPH) are distributed in Korean rice paddies but not easy to discriminate them in situ. Accurate discrimination of them is an indispensable process in the forecasting for their outbreak and control. Especially, innovative discrimination method for BPH was required because BPH was one of the most important insect pest of rice. Nymphs and adults of BPHs, SBPHS, and WBPHS, thus, were examined their morphological characteristics in the paddies and laboratory. The nymphs of BPH had different characters from those of SBPH and WBPH. The nymphs of BPH had white fluorescent spot between bottom of compound eye and antenna, while there was no that spot the other two species. The white spot was the brightest at the nymphs just after hatching and getting weaker as the nymph developed. At last the white spot was totally disappeared at the adult stage. This white spot was innovative criterium to discriminate nymphs of BPH, SBPH, and WBPH in rice paddies.

• Korean journal of applied entomology
• /
• v.44 no.3 s.140
• /
• pp.177-187
• /
• 2005

For the comparison of feeding behavior of Nilaparvata lugens among different rice varieties, electrical penetration graph (EPG) technique was used. Ten rice varieties were selected from national-widely recommended rice varieties cultivating in Chungnam province. The correlation between feeding duration and honeydew amount excreted was investigated, and the types of EPG pattern were analyzed among rice varieties. The EPG patterns divided into 6 types according to electrical specific feature, respectively. Type 1 pattern was a searching feeding sites, resting or wandering on a rice plant. Type 2 pattern was appeared when the insect untaken from phloem sieve element. Type 3 pattern was observed when the insect piercing into the rice plant. Type 4 pattern was observed when the insect salivating in rice plant. Type 5 pattern was observed when the insect ingesting from the xylem. Type 6 pattern was observed when the stylet moving in cell. Feeding duration time on Gum-nam was significantly shorter than Dong-jin, Dae-ahn, Dong-ahn, Dae-san. Also, on Gun-nam, it was shown that the brown planthopper did not penetrate the cuticle for a long time. The total number of excreted honeydew droplets by the brown planthopper was the greatest in Dong-jin variety and the least in Gum-nam variety. In proportion to phloem feeding time, the number of honeydew droplets had been increased. According to the results of EPG patterns and honeydew droplets analysis, N. lugens seems to prefer Dong-jin, Dong-ahn, Dae-san, and Dae-ahn to Gum-nam, Da-san, and Nam-chun rice plant variety.

• Korean Journal of Plant Resources
• /
• v.19 no.4
• /
• pp.488-490
• /
• 2006

In double cropping fields, there has been a risk of increase rice stripe viral disease outbreaking as the vector, small brown planthopper that overwinter in barley fields increases. Especially rice cultivation in Honam region has two types of cropping system such as rice only cropping in a season and double cropping both of rice and barley. In double cropping system, harvesting of barley could induce migration of the vector from barley to rice field. We found that the vector's density was different in rice fields by distance from barley field. The vector's density in rice field was highest 63 numbers within one meter from the neighbor barley field, and the numbers reduced greatly as the distance from barley field increases. The disease incidence according to rice cultivation methods was different, Donjin 1 was appeared to be a susceptible variety showing 2.4% and 2.5% of disease incidence in direct and transplanting cultivation, respectively. The small brown planthopper in a nearby rice field reach peak 3 days after the barley field was harvested.

• Korean journal of applied entomology
• /
• v.16 no.3 s.32
• /
• pp.171-179
• /
• 1977

Since the outbreak of the brown planthopper (Nilaparvata lugens) in 1915 caused tremendous losses in rice production, one of the more effective method of prevention of such a disaster could be the establishment of longterm forecasting system, In 1916 the author indicated there was a correlation between sunspot activities and brown planthopper and the white back planthopper outbreaks. However, the examples seem to be too small size to state a definite correlation. The purpose of the present study IS to revi~w the history of the brown planthopper outbreaks, and to establish a more effective forcasting system. The present forcasting methods are based on light trap catches of adults which already migrate into this country from mainland China. The regular cycle of 11.2 years of sunspot activity began in 1710, and was continued to present. To gather more records of brown planthopper, the author checked 'Joseon Wangjo Silrok' and analized the so-called 'Hwang' 'Hwang-chung' and 'Chung' which have multiple meanings, together with 'Samguk Sagi' 'Goryo Sa' and 'Munheon Bigo.' The results obtained by the about from review of these old literature citations revealed that ten species of insect and unknown species were involved: i. e., pine moth (Dendrolimus spectabilis), army worm (Mythimna separata), brown planthopper (Nilarvata lugens), white-back planthopper (Sogatella furcifera), migratory locust (Locutsa migratoria), rice stem borer (Chilo suppressalis,), mole cricket (Gryllotalpa africana), rice-plant weevil (Echinocnemus squameus), cut worm (Euxoa segetum), and mulberry pyralid Margaronia pyloalis) The suspected incidence of planthopper in old records expressed by 'Hwang' or 'Chung' revealed a total or 25 out of 37 in 'Samguk sagi,' 21 out of 49 in 'Goryo sa,' 9 of 73 in 'Wanjo-silrog,' and none of 8 in 'Munheon bigo' were planthoppers. Therefore, a total of 36 out of 167 records of insect incidence in the old literature can be possibly attributed to planthoppers. The brown planthopper and white-back planthopper migrate together to Korea every year from mainland China, However, the number of each species are differ by year. In 1975 outbreak the brown planthopper was dominant; and the white-back planthopper prevailed in 1946 and 1977 outbreaks, During the course of this study, the author was able to add a new record of outbreak of planthop per. In 1916 the white-back planthopper outbreak caused serious losses in Chungcheong-namdo and Jeonla-namdo, with losses estimated as high as 160 and 190 thousand seok (23.2 and 27.5 thousand M/T), in Naju and Secheon county, respectively. Since 1912, major outbreaks of brown planthopper or white-back planthopper have been recored 5 times. These occurrences coincide and well matched the period of minimum number of sunspots, With these authenticated records of planthoppers, the author believes there is a close correlation between brown planthopper and white-back planthopper outbreaks in Korea and sunspot activities. Therefore, in years of low number of sunspots, we should watch for and expect outbreaks of these. insects. At this time, it will be necessary to provide all possible prevention measures.

• The Plant Pathology Journal
• /
• v.17 no.6
• /
• pp.389.1-389
• /
• 2001

• Korean journal of applied entomology
• /
• v.15 no.3 s.28
• /
• pp.147-151
• /
• 1976

Laboratory experiments were conducted to evaluate the resistance of the new rice varieties Milyang $\#$21 and $\#$23 at the seedling stage to the brown planthopper(Nilaparvata lugens), small brown planthopper(Laodelphax striatellus), white-back planthopper(Sogatella furcifera), green rorice leafhopper(Nephotettix cincticeps) and zigzag-striped leafhopper (Recilia dorsalis) The varieties Yushin and T(N)-1 were used as susceptible check and the resistant check varieties were Mudgo to brown planthopper, ASD-7 :o small brown planthopper, Colombo to white-back planthopper, IR2061 (46763) to green rice leafhopper and Vellailanalgayan to zigzag-striped leafhopper. The varieties Milyang $\#$21 and $\#$23 were moderate in plant reaction only to the green rice leafhopper and $\#$23 was moderately resistant in plant rection only to the small brown planthopper. The nymphs of plant-and leaf-hoppers were more prefered Milyang $\#$21 and $\#$23 and susceptible check-varieties were more preferred for feeding than the resistant check-varieties. The green rice leafhopper and aigzag·striped leafhopper much more prefered Milyang $\#$21 and $\#$23 for oviposition, while brown planthopper and small brown planthopper more prefered the resistant cheeks than test varieties and susceptible checks. However, there was no any steady relationship in ovipositional preference between resistant and susceptible to the hoppers. Shorter nymphal-periods and higher rate of adult emergence were observed in the test varieties and the susceptible checks compared with the resistant checks. In conclusion, the varieties Milyang $\#$21 and $\#$23 seemed to be lack of true resistance to the plant-and leaf-hoppers from the viewpoints of antibiosis and feeding preference.

• Korean journal of applied entomology
• /
• v.33 no.3
• /
• pp.173-177
• /
• 1994

his study was conducted to Investigate the occurrence of small brown planthopper (SBPH), LaodeIpahx striatellus Fallen, and the ind~cence 01 rice virus diseases by d~fferent seeding dates in dryseeded rice. The occurrerlce of SBPH was the highest an nce seeded in May 11, followed byMay 1, May 21 and May 31. However. SBPH dld not occur on the rice seeded in June 10 duelo the rice was emerged after peak occurrence of first generailon adult of SBPH. The occurrenceof the first generation adult of SBPH was May 11 and it was 3-day earlier than that of infantnce transplanting. The ~nd~cencofe rice vlrus diseases, rice stripe vilus (RSV) and rice black-streakeddwarf virus (RBSDV), was the most severe at seeding date May 11. and then followed by May1, May 21 and May 31 Thus the incidence of "ce virus diseases was closely related with thedensity of the first generat~on adult of SBPH Rice yield was decreased by later seeding dates, although rice yield from May 1 to May 21 was relatively stable and hqii compared with laterseeding dates. Accordingly, there was slgniilcant relatlonsh~p between rice yield and seeding datesice yield and seeding dates

• Molecules and Cells
• /
• v.28 no.2
• /
• pp.131-137
• /
• 2009

Plant defensins are small (5-10 kDa) basic peptides thought to be an important component of the defense pathway against fungal and/or bacterial pathogens. To understand the role of plant defensins in protecting plants against the brown planthopper, a type of insect herbivore, we isolated the Brassica rapa Defensin 1 (BrD1) gene and introduced it into rice (Oryza sativa L.) to produce stable transgenic plants. The BrD1 protein is homologous to other plant defensins and contains both an N-terminal endoplasmic reticulum signal sequence and a defensin domain, which are highly conserved in all plant defensins. Based on a phylogenetic analysis of the defensin domain of various plant defensins, we established that BrD1 belongs to a distinct subgroup of plant defensins. Relative to the wild type, transgenic rices expressing BrD1 exhibit strong resistance to brown planthopper nymphs and female adults. These results suggest that BrD1 exhibits insecticidal activity, and might be useful for developing cereal crop plants resistant to sap-sucking insects, such as the brown planthopper.

• Journal of Life Science
• /
• v.7 no.4
• /
• pp.347-354
• /
• 1997

Some attempts were made to investigate the gentic characteristics of the brown planthopper(BPH), Nilaparvata lugens Sta${\aa}$l, biotypes. In terms of egg and nymphal periods, egg hatcgability, emergence ratio, and population change of BPH and plant damage of rice cultivars by the infestation of BPH biotypes and their hybrid progenies in field conditions. The egg and nymphal periods of the three of BPH biotypes and their hybrid progenies on Dongjinbyeo with no resistance gene were shorter than on rice cultivars with resistance gene. But the periods of biotype-2(♀) X 2(♂) (E) on Samgangbyeo with Bph-1 gene and biotype-3(♀) X 3(♂)(I) on Mirying 63 with bph-2 gene were as short as on Dongjinbyeo. The egg hatchability and emergence ratio of the three Bph biotypes and their hybrid progenies on Dongjinbyeo were higher than on the other rice cultivars, and those of E on Samgangbyeo and I on Miryang 63 were as high as on Dongjinbyeo. In rice paddy field, biotype-1(♀) X 1(♂)(A)$\sim$I infested on Dongjinbyeo, E onSamgangbyeo, and I on Miryang 63 were increased their population densities remarkably in next generation. Dongjinbyeo infested by A$\sim$I, and Myryang 63 infested by I were hopperburned at 60 days after infestation and had a damage rating of 0.9. But Samgangbyeo infested by E was no hopperburn(damage rating: 7.3) though it showed high BPH population at 60 days after infestation.

• Korean journal of applied entomology
• /
• v.42 no.1
• /
• pp.57-63
• /
• 2003

Accurate forecasting of occurrence time and abundance of insect pests is essential for developing technology of integrated pest management system. Digital image processing algorithms were utilized to automatically recognize rice planthoppers which are major insect pests in the rice cultivation field and were subsequently used to estimate densities in the field for efficient forecasting of insect pests. To the images taken in the rice field, image decomposition, top-hat transformation, threshold, and minimum and maximum filter were implemented for patterning individually the brown planthopper specimens attached at the bottom area of rice stems. In average 95.8cio of images were correctly recognized for estimating densities by the developed system, and the recognition rate was higher than that obtained from direct observations by experienced observers. Furthermore, the size of the recognized specimens was measured and was used for estimating the age structure in the observed brown planthopper populations.