• Korean journal of applied entomology
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• v.56 no.2
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• pp.203-212
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• 2017

Thirty-three species of insect pests including of two-spotted spider mite, Tetranychus urticae Koch, and air-breathing land snail, Acusta despecta Sowerby, were observed on mulberry for producing mulberry fruits in Jeonbuk province from 2015 to 2016. Of these, 8 species of insect pests, including of mulberry thrips, Pseudodendrothrips mori Niwa, are regarded as major insect pests. Of the 25 species observed before harvesting, 6 species-P. mori, Anomoneura mori, Pseudaulacaspis pentagona, Baris deplanata, Menophra atrilineata and T. urticae-are regarded as major insect pests. In contrast, of the 20 species observed after harvesting, 5 species-P. mori, P. pentagona, Glyphodes pyloalis Walker, Hyphantria cunea Drury and T. urticae-are regarded as major insect pests. Eight of the major insect pest species and nine other insect pest species-including Hexcacentrus unicolor Serville, Malcus japonicus Ishihara et Hasegawa, Halyomorpha halys stal, Xylosandrus germanus Blandford, four species of Repidoptera (Bombyx mandarina Moore, Euproctis subflava Bremer, Acronicta major Bremer, Agrotis trifurca Butler), and Acusta despecta Sowerby-were observed at all sites studied, although occurrence of the insect pests observed on mulberry varied from site to site.

• 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.11 no.2
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• pp.61-68
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• 1972

This study has been carried out to investigate the varietal resistance of Tong-il rice variety (IR-667) at the seedling stage to the brown planthopper. Nilaparvata lugens STAL, and further to know the biological effects of the varieties to the insects. The results obtained were as followings; 1. Tong-il variety tested in this experiment was susceptible to the brown planthopper but it seemed to be a little more tolerable than the Japonica varieties which had been recommended in Korea. 2. Tong-il variety (Suwon 213, Suwon 213-1, Suwon 214, and Suwon 215) was highly prefered by brown planthopper for feeding to the Korean recommended varieties Paltal, Jinheung, Akibare, and Shin #2. 3, The resistant varieties Mudgo, Kayama MGL-2, and Karsamba ASD-7 which showed low feeding preference exhibited higher ovipositional preference than the susceptible varieties. Relatively greater number of eggs was recorded on the Tong-il variety (Suwon 213, Suwon 213-1, and Suwon 215) in comparison with the Korean recommended varieties, 4, When the female brown planthopper adults were caged on Tong-il variety (Suwon 214) and the resistant variety Karsamba ASD-7 separately, greater number of eggs were observed on Suwon 214 and less on Karsamba ASD-7, while when two varieties Suwon 214 and Karsamba ASD-7 were given together in the same cage, Karsamba ASD-7 was much more prefered for oviposition to Suwon 214. 5. There was no difference in e99 Periods and their hatchal\bility between the resistant and susceptible varieties, but nymphal periods, rate of adult emergence, longevity of the adult, and its fecundity were significantly different according to the varieties.

• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.49-55
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• 1984

This study was carried out to investigate the biological performance of the brownplanthopper, Nilaparvata lugens Stal, reared on rice plants at different growth stages; maximum tillering, booting, heading with and without panicles, and milking. The results obtained are as follows: The rice plants at the maximum tillering stage gave the best in the longevity, oviposition period, and the total number of oviposited eggs for the macropterous females, and the worst with the booting stage. For the brachypterous females, however, the best results were obtained from the rice of which their panicles had removed after heading. There was no significant difference in the hachability of eggs and the developmental period of the nymphs in the next generation, but the nymphal mortality was the highest with the milking stage and the lowest with the maximum tillering and heading stage without panicles. The longest life span was shown in males derived on the maximum tillering stage, and the shortest for milking(macropterous type) or booting (brachypterous type) stages. Coefficientes of variances in longevity and number of eggs for the adults emerged from heading stage without panicles were lower than those with panicles intact, and such trend was more obvious in brachypterous adults, especially for the females. The biological performances of the BPH have close relationship with the translocated organic material at the feeding site which showed considerable difference with the growth stages of the rice.

• Korean journal of applied entomology
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• v.30 no.1
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• pp.10-17
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• 1991

Cuticular penetration and detoxication as mechanisms of resistance to the carbamate insecticides in fenobucarb-selected($R_{f}$) and carbofuran-selected($R_{c}$) strains of the brown planthopper (N. lugens Stal) were investigated. Rates of penetration were not significantly different in the susceptible and resistant strains. However, total amount of excretion of the $R_{f}$ and $R_{c}$ strains were much larger than that of the susceptible strain. Fenovucarb and carbofuran were in vivo metabolizd much faster in the $R_{f}$ strain than in the susceptible strain. OSBP(o-sec-butyl phenol) and 3-ketocarbofuran phenol were invitro the major metabolites of fenobucarb and carbofuran in the brown planthopper, respectively. Total amount of the two major metabolites were produced abotu 2 times larger in the $R_{f}$ and $R_{c}$ strains compared to the susceptible strain. OSBP and 3-ketocarbofuran phenol were not so toxic to the brown planthopper ($LD_{50}$ >100 $\mu\textrm{g}$/g hopper). Based on our data, detoxication plays a large role in resistance to fenobucarb and carbofuran in the resistant strain of BPH, although several resistance factors maybe involved.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.543-550
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• 1992

Residual and biological effects of buprofezin(25% WP) on the larvae of the brown planthopper(BPH), Ni/aparvata /ugens SUlI, were studied by pot experiments. Residual lethal effects on the 2nd instar larvae lasted significantly long, and were higher with application rates. The rate of 17.50 g a.i./10a showed ca. 90% mortality even on 35 days after treatment (OAT). $RLT_{90}$ and $RLT_{50}$(residual lethal time that can show 90% and 50% mortality, respectively) with rates of 5.78-11.50 g a.i./lOa were 9.0-13.5, and 16.8-22.8 days, respectively. It was estimated that 13.00 and 4.44 g a.i./lOa were the rates of buprofezin which could show mortalities of 2nd instar BPH larvae above 95% and 50% until 15 OAT, respectively. The residual lethal effect of 7.00 g a.i./10a on the 1st instar BPH larvae was 100 % even on 17 OAT. $RLT_{50}$ was 32.5 days which was 15 days longer than $RLT_{50}$ for the 2nd instar larvae. Buprofezin with 7.0 g a.i./lOa showed 100% and 70% mortality for 1st-4th and 5th instar BPH larvae, respectively. Longevity of a female BPH which emerged from the 5th instar larvae treated by buprofezin was greatly reduced, and its fecundity was nearly zero.

• Korean journal of applied entomology
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• v.22 no.4 s.57
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• pp.244-250
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• 1983

This study was carried out to analyst the damage due to the brown planthopper, Nilapalvata lugens Stal, at different stages(maximum tillering, booting, heading, and milking) of rice. The results are as follows: The population density of the migrating and the first generations of the brown planthoppers seemed not to be large enough to cause significant effects on the plant height and the number of tillers, while the second and the third generations caused significant reduction in 1000 grain weight(Yl) and the filled grain percentage$(Y_2)$. They were very closely related to the population density(X) of tile second generation of the BPH; $$Y1(g)=25.602-0.0213X(r=-0.5205^{**})$$ $$Y2(\%)=76.97-0.1370X(r=-0.4820^{**})$$ The relationship between rice yield (Yg) and the accumulated total density (X) of BPH per hill by the time of harvest; $$Y(g)=24.694-0.0576X(r=-0.6959^{**})$$ Since the source of the outbreak BPH is the first generation, it nay conclude that the detailed information on the population status of the first generation; density, age components, ratio of the brachypterous form, are very important in relation to management of the pest.

• Korean journal of applied entomology
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• v.32 no.1
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• pp.68-75
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• 1993

Morphometric investigations of the leg characters of both sexes of brachypterous Korean N. lugens biotypes were made. Simple and multivariate statistical analyses revealed that the three N. lugens biotypes differed from one another. The amount of variation and segregation between and among the three biotype populations were approximated by the scatter plot diagrams based on the computed discriminant scores. The variables of leg characters provided the most significant segregations of three biotype populations, thus, categorizing the three biotypes as distinct intraspecific populations of N. lugens.

• International Journal of Industrial Entomology and Biomaterials
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• v.10 no.2
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• pp.137-141
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• 2005

Though many insecticides are commercially available, development of resistance, pest resurgence and effects on non-target organisms led to the search for alternate insect pest management (IPM) strategy based on larval growth and reproductive fitness. Reproductive potential of insects depends on its acquiring of vitellogenic competence which is under hormonal control. Exogenous application of analogues of JR (JHAs) and ecdysterone could derail normal development and reproduction in insects by manipulating an array of physiological processes. In the rice pest, brown planthopper, Nilaparvata lugens, JHA, hydroprene induced metathetely from the fifth (final) instar nymphs in an age-dependent manner. Day 0 of the final instar showed highest sensitivity to induce this abnormal development. Adults emerged from treated day 3 nymphs looked normal. Both the morphotypes were reproductively incompetent and showed partial to complete sterility. Pre-adult exposure of the ovarian tissue to hydroprene suppressed mitotic division of germinal cells and induced abnormalities in the later s1ages of growth and differentiation of ovary in N. lugens. More over the nymphal exposure to hydroprene inhibited patency changes of follicular epithelium and affected competence of the follicles for yolk sequestration. In the absence of ovarian growth and oocyte differentiation, germarium found disintegrated, trophic core regressed and terminal oocytes resorbed. Hydroprene exposure to newly ecdysed brachypterous females did not affect ovarian development and egg production. Proper larval-adult transition appeared as a. prerequisite for vitellogenic competence in N. lugens for which the ovarian tissues must be exposed to ecdysterone in the internal milieu devoid of JH.

• The Korean Journal of Pesticide Science
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• v.5 no.1
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• pp.24-29
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• 2001

This study was conducted to investigate insecticidal activities of Ginkgo biloba (L.) leaves-derived bilobalide and its hydrolysis and oxidation products against adults of Nilaparavata lugens Stal. To find out active insecticidal moiety of bilobalide, decomposed intermediates and derivatives of bilobalide were made by hydrolysis, oxidation, and acetylation. The structures of hydrolysis product by base and oxidation product by acid were identified as cyclopentenone analogues and trilactone sesquiterpene from dehydration of bilobalide, respectively. Insecticidal activities of the decomposed intermediates and the derivatives of bilobalide decreased in the order of bilobalide, monoacetate, ginkgolide C, oxidation product, diacetate, and hydrolysis product. Therefore, trilactone structure of bilobalide may be essential for its insecticidal activity.