• Korean journal of applied entomology
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• v.18 no.1 s.38
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• pp.15-21
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• 1979

To determine the population regulation mechanism of the Green rice leafhopper (Nephotettix cincticeps Uhler), the responses of the population increase to initial densities and the effect of host conditions and temperatures during developmental period were investigated. In the out door experiment, the increasing ratio of population density of this pest was reduced as initial density increased and this density-dependent effect was differ in accordance with host condition. Host conditioning through feeding resulted in reduction in numbers of eggs produced and it seemed to be affected by some inhibiting materials secreted by the pest during feeding. though the direct effect of feeding can't be excluded. The population growth was related with population density and host stage. Thus in late planted units, the host stage was favourable to the growth of population at low initial insect density but unfavourable at relatively high initial insect density and in early planted units, vice versa. The temperature during developmental stages definitely affected the determination of sex ratio of adult population and reduced numbers of eggs produced. The most favourable temperature to the population increase was $290^{\circ}C$, and at high temperature, $33^{\circ}C$, severe reduction of fecundity was shown ana it seemed to be caused by the simple reduction in numbers of eggs produced.

• Korean journal of applied entomology
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• v.32 no.3
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• pp.338-347
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• 1993

The study was to investigate the bionomics, host plants, and oviposition preference of Hishimonus sellatus Uhler. It has 5 generations under natural conditions and the peak of the 3rd generation was observed about mid and late August. Its average developmental durations were 80 days in spring, 69 days in summer, and 77.8 days in autumn. The lengths of each stage were 0.8mm in eggs, 0.9mm in 1st instar, 1.4mm in 2nd instar, 2.1mm in 3rd instar, 2.5mm in 4th instar, 3.2mm in 5th instar, 4.1mm in female, and 3.8mm in male. Hishimonus sellatus overwintered as egg in Morus alba, Humulus japonicus, and Zizyphus jujuba begining mid October, and attacked the shoot of M. alba and H. japonicus about mid and late May, migrated to the Zizyphus jujuba from late June to early July. Female oviposites 32~62 eggs into epidermis of shoot, vagina and vein during their life. The preferred host plants of H. sellatus were Humulus japonicus, Morus alba, Zizyphus jujuba, and ligustrum obtusifolium. Highly preferable oviposition site was H. japonicus, M. albal, Z. jujuba, and L. obtusifolium, etc. On audlt longevity, the host plants as H. japonicus, M. alba, and Z. jujuba were 43$\pm$2 days and A. brevipedenculata, C. mimosoides, L. obtusifolium, V. rosa, A. sinicus and, A. graveolens were more than 25 days, and other host plants were less than 20 days.

• Korean journal of applied entomology
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• v.14 no.2 s.23
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• pp.65-70
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• 1975

The study was planned to detect resistance levels of striped rice borers (Chilo suppressalis Walker) and green rice leafhoppers(Nephotettix cincticeps Uhler) from different localities to organophosphate and carbamate insecticides using topical application. Strains of overwintering striped rice borers were collected from 7 different areas in Gyeonggi Province and they were kept under conditions of about $25^{\circ}C$ for 10 days. Overwintered and reared larvae of striped rice borers were compared for response to insecticides. The strains of green rice leafhopper were collected from Iri, Milyang, Pyongtaek, Echeon and Suweon. Insects were multiplied in the lab. All insecticides tested were organphosphates(MPP, MEP and Diazinon) and carbamate (NAC), which have been used in control of rice insect pests for over past 10 years. The results obtained were as follows; a. With MPP compound, resistant levels of the Joam, Suweon, and Echeon strains of C. suppressalis were from 2 to 4 times as compared with the Yangpyong strain. b. With MEP insecticide, resistant levels of the Kimpo, Pyongtaek, Yongin, Echeon, Suweon, and Joam strains of C. suppressalis were from 2 to 6 times as compared with the Yangpyong strain. c. With Diazinon, resistant levels of the Suweon strain of C. suppressalis were 3 times greater than the Yangpyong strain; but the resistant levels of Kimpo, Pyongtaek, Yongin, and Echeon strains approximated the later. 4. The overwintered larvae of C. suppressalis were more tolerant to the insecticides than the larvae reared in the lab. e. With MEP, resistant levels of the Iri, Milyang, and Pyongtaek strains of N. cincticeps to the Suweon strain showed 13, 8, 7 and4 times, respectively. f. With MPP, resistant levels of the Iri and Pyongtaek strains of N. cincticeps were 7 and 4 times as compared with the Suweon strain, respectively. g. With NAC, resistant levels of the several strains of if. cincticeps showed no difference, and seemed not to have developed resistance yet.

• International Journal of Industrial Entomology and Biomaterials
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• v.5 no.2
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• pp.141-151
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• 2002

The success of sericulture industry in India is mainly attributed to the well-planned annual sericultural activity and the systematic implementation of pest preventive and control measures. The insect spectrum of silkworm and its food plants is complex and plays a major role in limiting the production of silk. Insects cause extensive damage to plant whereas predators and parasites either kill the silkworm larvae or force them to spin flimsy cocoons. Unilateral control measure against this pest is mainly based on the use of synthetic organic insecticides. Though these approaches initially paid rich dividends, the undesirable consequences soon surfaced. Insecticide induced resurgence of gall midges, leafhopper, leaf roller, secondary pest out breaks and development of pest biotypes has led to realization of Integrated Pest Management in sericulture. Various components of IPM, viz. Host plant resistance, cultural practices, biological control, chemical control and integrating them at various technological levels have been studied. Sources of host plant resistance have been identified for some of the major insect pests. High yielding mulberry variety has been propagated and their resistances towards major pests have been recorded. Cultural practices like pruning, pollarding, judicious use of nitrogen, optimum spacing and weed management have preyed to be the powerful tools in containing pests. Natural control over the pest population build- up exerted by the wide range of parasitoids, predators and pathogens has been well documented with identification of natural enemies and studies on their potential. Augmentation, through inoculation or inundative releases of parasitic arthropods, is the most direct way of increasing the numbers of these beneficials in sericulture.

• Korean journal of applied entomology
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• v.16 no.1 s.30
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• pp.65-67
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• 1977

Yield losses from rice dwarf virus infection are significant in Korea. Rice dwarf virus(RDV) was purified and RDV-antiserum was produced. The purified virus, mixed with an adjuvant(1:1) was injected every 10 to 14 days into rabbits. Three injections .were sufficient to produce an antiserum of 1/4,096 titer. The produced antisera will be used to facilitate the detection and identification of RDV in rice plants and in the RDV leafhopper vectors.

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.159-163
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• 1987

The toxicity of the mixture at 1 to 1 ratio among the insecticides, BPMC, carbofuran, diazinon and monocrotophos to the brown planthopper (BPH), Nilaparvata lugens and green leafhopper (GLH), Nephotettix virescens were tested and compared to their toxicities of individual insecticides. Among the mixtures, carbofuran combinations with BPMC and diazinon showed synergistic effect in toxicity to BPH. There was also synergistic action in toxicity with mixture of BPMC plus monocrotophos to GLH. Other combinations were independent in toxic action to both insects.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.141-144
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• 1997

Studies were conducted to investigate the incidense of insect pests in transplanted and direct seeded paddy fields in southern region of Korea. Population dencities of the rice green leafhopper (RGLH: Nephotettix cincticeps Uhler) and rice leaffolder (RLF: Cnaphalocroch medinalh Guenee) were higher in machine transplanted than in direct seeded, but the brown planthopper (BPH: Nilaparvata lugens Stal) and smaller brown planthopper (SBPH: Laodelphax striatellus Fallen) were abundant in direct seeded. However, no significant difference was found between machine transplanted and direct seeded fields in the incidense of rice stem borer (RSB: Chilo suppressalis Walker), whiteback planthopper (WBPH: Sogatella furcifera Horvath), and rice stem magot (RSM: C'hlorops oryzae Matsumura). Occurrence of rice key pests were affected more by transplanting time than other cultural practices. Later transplanting induced higher populations of BPH, WBPH, SBPH, RGLH. However, RSB and RLF caused higher damage in earlier transplanted paddy field.

• Korean journal of applied entomology
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• v.35 no.2
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• pp.132-136
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• 1996

These studies were carried out to investigate the occurrence of rice insect pests related to different transplanting times and N-P-K-fertilizer levels of paddy field in Southern region of Korea. The population densities of brown planthopper (BPH: Nilaparvata lugens Stal), whitebacked planthopper (WBPH: Sogatella furcifera Horvath), small brown planthopper (SBPH: Laodelphax striatellus Fallen), green rice leafhopper (GRLH: Nephotettix cincticeps Uhler), rice stem maggot (RSM: Chlorops oryzae Matsumura), striped rice borer (SRB: Chilo suppressalis Walker), and rice leaffolder (RLF: Cnaphalocrocis medinalis Guenee) were affected more by transplanting time than the fertilizer levels. The later transplanting time induced the higher population densities of BPH, WBPH, SBPH, GRLH, RSM, whereas SRB and RLF were affected by earlier transplanting time in paddy field. The major pests except GRLH and SRB were increasingly induced by higher N-fertilizer level in the late transplanting.

• Korean journal of applied entomology
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• v.31 no.3
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• pp.256-275
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• 1992

Insects are among the most important abiotic and biotic constraints to rice production. National rice research programs are in various stages in the development and implementation of integrated pest management (IPM) stratagies for rice insect control. Among the various control tactics, insect resistant cultivars are sought as the major tactic in rice IPM. Through the activities of interdisciplinary teams of scientists significant progress has been made in the development and release of insect resistant cultivars to farmers. Because of its compatibility with other control tactics insect resistance has proven to fit well into the IPM approach to rice insect control agents and minimize the need for insecticide applications. The development of biotypes which overcome the resistance in rice plants has been a significant constraint in the breeding of rice for resistance to insects. Most notable examples in Asia are the green leafhopper, Nephotettix virescens, brown planthopper, Nilaparvata lygens and the Asian rice gall midge, Orseolia oryzae. The current breeding stratege is to develop rice cultivars with durable resistance on which virulent biotypes cannot adapt. In spite of the significant progress made in the breeding of insect resistant cultivars there are still numerous important rice insect species for which host plant resistance as a control tactic has not been fully utilized. Advances in biotechnology provide promise of solving some of the problems that have limited the use of host plant resistance as a major tactic in the integrated management of rice insect pests.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.217-220
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• 1977

During 1976 the effects of carbofuran placement in the root zone of the rice plants, the varieties Palkweng and Yushin, were evaluated for control of common rice pests in the paddy field at the Honam Crops Experiment Station. The methods of insecticide placement included the use of capsule formulation and liquid injection by the root-zone liquid insecticide injector designed at the International Rice Research Institute. The single ro~t-zone application of carbofuran at 2 days after transplanting was compared with two and fcur broadcast applications of carbofuran and diazinon. Capsules were the most. effective in controlling the striped rice borer (Chilo suppressalis), small brown plant-hopper (Laodelphax striatellus), green rice leafhopper (Nephotettix cincticeps) and stripe virus disease which is transmitted by the small brown planthopper. However, one injector application of carbofuran was equal or better the broadcast applications. Their control effectiveness were more significant on Palkweng susceptible to common rice pests than on Yushin resistant to the stripe virus disease.