• Proceedings of the Korean Society of Crop Science Conference
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• 2021.04a
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• pp.35-35
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• 2021

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.04a
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• pp.91-91
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• 2021

• Korean journal of applied entomology
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• v.18 no.4 s.41
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• pp.149-152
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• 1979

The relative toxicity of some of the insecticides which have been used for the control of paddy rice insect pests in Korea was evaluated in the laboratory with the brown planthopper (BPH) Nilaparvata lugens, and a predaceous paddy spider Pirata subpiraticus. In order of the relative toxicity (LD5O value to spider/LD50 value to BPH) were PAP (0.4), MPP(0.1), MEP(1.8), diazinon(2.8), carbofuran(7.5), NAC(11.3), BPMC(17.5), Pyridaphenthion(35.9) and MIPC(65.7). MIPC and Pyridaphenthion were considered as having the desirable selective toxicity for the spider and the BPH.

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

• Journal of Life Science
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• v.7 no.4
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• pp.347-354
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• 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
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• v.17 no.1 s.34
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• pp.53-63
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• 1978

The object of this study is to clarify the varietal resistance to green leaf-and planthoppers and to evaluate the nature of the resistance to the insects in connection with the antibiosis. This study investigated the reaction of the 46 rice varieties to insects including recommended varieties of Korea. At seedling stage they were infested with second or third instar nymphs. The results were as follows. 1. The body weight of brown planthopper was increased more than 3 times on susceptible rice variety Mankyung at 15 days after infestation but only 2 times on resistant mudgo. 2. The mortaliy of the brown planthopper was significantly different between resistant and susceptible rice plant, showing 74 percents in resistant Mudgo while 31.2 percents in susceptible Mankyung at 15 days after caging. 3. Most of the rice varieties tested showed highly susceptible reaction to brown planthopper except Mudgo, KR 108-243-1 and HR 529-41-3-2 as resistant varieties, and Akamochi, Satominori, IR 24 and IR 8 as moderately susceptible ones. 4. In the test of varietal resistance to white-backed planthhopper, Mudgo, KR 108-243-1, KR 109-154-2 and HR 529-45-2 and HR 529-45-3-2 were resistant, and Suweon #82, Tongil, IR 8, Palkeum, Iri #309, Hokwang and Chukoku #31 were moderatly susceptible. 5. Most of the varieties tested were observed as highly resistant to green rice leafhopper, but Tongil, Suweon 82, IR 24, Milsung and Chukoku #31 were moderatly susceptible. 6. The new bred lines HR 108-243-1 are multi-resistant to brown planthopper, green rice leafhopper and White-backed planthopper, and some others showed moderate susceptibility.

• The Korean Journal of Pesticide Science
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• v.17 no.4
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• pp.419-427
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• 2013

The insecticidal activity of 124 plant essential oils and control efficacy of six experimental spray formulations (SF) containing 0.25, 0.5, 1, 2.5, 5, and 10% of the selected oils was examined against both nymph and adult of the citrus flatid planthopper, Metcalfa pruinosa using direct contact applications (leaf dipping and spray). Reponses varied according to dose (1,000 and 500 mg/L). When exposed at 1,000 mg/L for 24 h using leaf dipping assay, 19 essential oils showed strong mortality (100%) among 124 essential oils screened. At 500 mg/L, 100% mortality was observed in cinnamon technical, cinnamon green leaf, cinnamon #500, cassia tree, citronella java and pennyroyal followed by origanum, thyme white, grapefruit, savory, fennel sweet, aniseed and cinnamon bark showed considerable mortality (93.3-80%) against nymphs of M. pruinosa. The moderate mortality (73.3-60%) was found in thyme red, tagetes, calamus, lemoneucalptus and geranium. Oils applied as SF-10% sprays provided 100 % mortality against adult M. pruinosa. One hundred mortalities were achieved in cinnamon technical at >SF-0.5 formulation, in cinnamon #500, cinnamon green leaf and penny royal at >SF-2.5. To reduce the level of highly toxic synthetic insecticides in the agricultural environment, the active essential oils as potential larvicides could be provided as an alternative to control M. pruinosa populations.

• 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.

• Journal of Life Science
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• v.28 no.3
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• pp.357-360
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• 2018

This study developed a method to minimize rice damages and enhance timely control by accurately classifying Whitebacked Planthopper (WBPH). The body size of the 1st-3rd instar was 1.5-2 mm, and the body size of the 4-5 instar was 2.5-3.5 mm. In the third instar, the ratio of the front wing bud and the back wing-bud was 1:1. The fourth instar occupied 3/4 of the front wing-bud, and the 5th instar showed that the front wing-bud covers the back wing-bud. It was confirmed that the 1st instar does not have a sensory plate, the 2nd instar has 2-3, the 3rd instar has 4-5, the 4th instar has 6-9, the 5th instar has 10-15, and the adult instar has 15-20 sensory plates. The female spawning organs were reddish when the spawning horn was inserted. WBPH showed that the larvae of 2-3 larvae most actively feed on rice, and the damaged area was the stem of rice near the ground. In addition, a partial black wound was observed after the feeding. WBPH-susceptible 'Chucheong' was yellowish, and early growth was slower than that of 'Cheongcheong', which was resistant; moreover, a difference between susceptibility and resistance was observed. The identification of the number of such wounds in the bioassay will be a better basis for understanding the difference in susceptibility between WBPH strains and cultivars. These results will be used as basic data for cultivating the WBPH-resistant varieties of rice.

• 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.