• Korean journal of applied entomology
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• v.48 no.3
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• pp.285-294
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• 2009

A study was conducted to find out plant flora, the occurrence of insect pests and natural enemies in the fallow paddy fields of Jeonnam and Jeonbuk provinces from 2004 to 2005. They were identified as 124 plant species in 32 families, 58 insect pest species in 30 families and 11 natural enemy species in 9 families. Plant species belonging to Poaceae and Asteraceae were founded as 28 and 18 species, respectively, and dominated significantly among plants growing in the fallow paddy fields. In insect pests, Conocephalus chinensis, Nysius plebejus, Cletus punctiger, Eysarcoris aeneus, Nephotettix cincticeps, Laodelphax striatellus and Tipula sp. occurred significantly in the fallow paddy fields. Among them, occurrences of N. cincticeps and L. striatellus were low from May to June, and that of L. striatellus was high in August and September. In insect natural enemies, Coenagrion sp., Harmonia axyridis, Propylea japonica and Eristalis tenax occurred significantly in the fallow paddy fields.

• 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.15 no.3 s.28
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• pp.111-126
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• 1976

Regional differences in economic importance of the four species of rice leafhoppers, viz., Laodelphax striatellus, Nephotettix cincticeps, Nilaparvata Iugens and Sogatella furcifera, were analyzed and discussed based on population surveys conducted in Suweon and in southern and south-western coastal areas. The economic importance of L. striatellus and N. cincticeps, which are found throughout the year in Korea, seems to be less in middle regions. This is believed due to effective natural control through severe winter climate, cultural practices in rice and barley growing, and natural enemies such as spiders. However, the economic importance of these two species is significantly greater in southern regions with a less severe winter climate, and where cultural practices in rice and barley favour synchronization between the life cycles of insects and the seasonal succession of host plants. with regard to N. lugens and S. furcifera, which cannot overwinter in Korea, initial populations are the result of long distance migration across the East China Sea. Weather elements related to their migration result in more abundant immigrants of these two species in southern than in middle regions. Thus, different policies are needed for the integrated control of rice leafhoppers in middle and southern Korea.

• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.253-259
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• 1985

This paper presents a natural enemy complex of plant and leafhoppers in rice plants and a relationship between the host insects and their natural enemies. Feeding preference of major paddy spiders have been tested. To date, 32 species of natural enemies of plant and leafhoppers have been recorded, including 30 species of parasites and predators (15 parasitoids, 14 predators and nematode) and 2 species of insect pathogens. Some of species have shown great potential for controlling plant-leafhoppers populations; parasites, Anagrus nr. flaveolus, Gonatocerus sp., Haplogonatopus atratus and paddy spiders. Pirata subpiraticus and Gnathonarium dentatum. Plant and leafhoppers-natural enemy relationship have been observed in different developmental stages of the host insects. Pirata sub-piraticus is the most active to searching the host insects and also prefered nymphs to adults.

• Korean journal of applied entomology
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• v.23 no.3 s.60
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• pp.158-165
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• 1984

These studies were carried out to investigate the bionomics of Gonatocerus sp. y (Hymenoptera: Mymaridae) , an egg parasite of the green rice leafhopper, Nephotettix cincticeps Uhler (Homoptera: Deltocephalidae) under laboratory and field conditions at Gyeongnam Provincial O.R.D. in Jinju from 1982 to 1983. The developmental period of each life stage was observed under four different temperature conditions from $15^{\circ}C\;to\;30^{\circ}C\;with\;5^{\circ}C$ increment. The development from egg to adult at 15^{\circ}C,\;20^{\circ}C,\;25^{\circ}C,\;and\;30^{\circ}C $ was completed in an average of 53, 25, 15, and 12 days and the females laid an average of 28, 48, 42, and 32 eggs respectively, with a maximum of 98. And most of the eggs were laid in the first two days after emergence. The time of adult emergence was determined under $25{\pm}1^{\circ}C$ condition. More than $76\%$ of the wasps emerged in the morning and the rest of them emerged in the afternoon. The average sex ratio between male and female was 1 : 5 when the wasps were developed from fertilized eggs. The longevity of female was greater than that of male when honey and water were provided as food, however, it was not when only water was supplied as food. The average longevities of females were 30 days at $15^{\circ}C$ and 15 days at $20^{\circ}C$ when honey and water were given as food. The peak precent parasitism of Gonatocerus sp. v on Nephotettix cincticeps in fallow fields was observed between late April and early May. The percent parasitism of the wasps In fallow fields was an average of 49\~59.9\% $ in Gyeochang, Namji and $23.2\~36\%$ in Namhae. The parasitic activities of the parasite had four peaks in paddy field, however, the highest peak was observed between late August and early September. The Percent e99 Parasitism of Gonatocerus sp. y was an average of $12.3\%$ on second the generation and $24.6\%$ of third genera lion of Nephotettix cinrticeps.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.55-66
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• 1997

This study was conducted to analyze arthropod community patterns in small rice fields associated with different planting methods (water seeding, drill seeding, and hansplanting) in Suwon and Icheon in 1994. Total 15 orders and 45 families of arthropods were collected. The arthropod community was analyzed using guild categories. The arthropods were found in the order of 'natural enemy>pest(phytophage)>non-pest' in their densities in all sites. The pest (phytophage) species were mainly Homoptera and dominated by Delphacidae (Nilaparvata lugens Stsl, Sogatella fircifera Horvath and Laodelphax striatellus Fallen) and Cicadelidae (Nephotettir cincticeps Uhler). They constituted >80% of pest abundance. Differences in pest abundance were not found among rice fields associated with different planting methods. Spiders were the most dominant group in the natural enemy and constituted >90% of natural enemy abundance. Hunting spiders constituted >SO% of spider abundance and were dominated by Pirata subpiraticus Bos. et Str. (Lycosidae). Pacliygnatha clerki Sundevall (Tetragnathidae) was a dominant species in webbing spiders. No differences were found in species richness and diversity in spider community among rice fields associated with different planting methods. The nonpest species were mainly Diptera and occurred abundantly in early growing season and decreased drastically as rice development proceeded. The non-pest abundance was higher in direct seeding sites than in transplanting site, and especially abundant in a drill seeding site.

• 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.

• Journal of Life Science
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• v.11 no.2
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• pp.121-125
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• 2001

Some attempts were made to investigate the biological characterisitcs of the green rice leafhopper(GLH) , Nepthotettix cincticeps Uhler in terms of nymphal development, emergence ratio. preovipositional period, growth index, adult longevity and fecundity fed on rice cultivar, Chucheongbyeo with no resistance gene and water foxtail, Alpecurus aequalis Sobol. var. amurensis Ohwi at 20 and $25^{\circ}C$ with a 16L;8D photoperiod. Development period of nymph on rice cultivar and water foxtail at $25^{\circ}C$ was shorter than that at 2$0^{\circ}C$ by twofold. The nymphal period of female was about one day longer than that of male. The mean emergence ratio of female and male on rice cultivar and water foxtail was 40.0, 76.7, 38.3, 73.3% at 20 and $25^{\circ}C$, respectively. Preovipositional period on rice cultivar and water foxtail at $25^{\circ}C$ was shorter that at 2$0^{\circ}C$ by twofold. Growth index on rice cultivar adn water foxtail at $25^{\circ}C$was higher than that at 2$0^{\circ}C$ by fourfold. Under the 20 and $25^{\circ}C$ condition, the longevity of female and male was longer on water foxtail than on rice cultivar, but the fecundity of GLH was higher on rice cultivar than on water foxtail. In conculsion, water foxtail seems to be adequate for spring host of GLH.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.536-542
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• 1992

Control effects of carbofuran soil incorporation just before transplanting on the early occur-ring rice insect pests were studied in the rice field. Also, its residual effects on the brown planthopper (BPH) were studied by pot experiments. Carbofurn soil incorporation in late May was much more effective in controlling the early occurring rice insect pests such as small brown planthopper, green leafhopper and rice stem borer than carbofuran broadcasting or diazinon (3G) + BPMC (50% EC) treatment in mid June. Residual effects of carbofuran soil incorportaion on the female adult BPH decreased ca. a half one month after treatment. However, its residual effects on the next generation of the BPH lasted much longer; control effects on the next generation were above 90 and 70% on 37 and 46 days after treatment, respectively. From these results, it is thought that carbofuran soil incorporation just before rice transplanting can be a good control method to the early occurring rice insect pests and the brown planthopper immigrating during June. Also, it can suppress immigrating BPH popula¬tion moderately in early July.

• Korean journal of applied entomology
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• v.41 no.2
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• pp.91-97
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• 2002

This study was conducted to determine the effects of temperature and food onthe nymphal development and adult longevity of the green virid bug, Cyrtorhinus lividipennis Router. Nymphal period was 13.2 to 13.7 days at 24$^{\circ}C$, 10.4 to 10.9 days at 28$^{\circ}C$, and 9.0 to 9.3 days at 32$^{\circ}C$. Number of eggs predated by nymph was 10.6-14.3 at 24$^{\circ}C$, 7.5-9.2 at 28$^{\circ}C$, and 5.8-7.5 at 32$^{\circ}C$. Amount of predation was highest on BPH, followed by SBPH, WBPH, and GLH. Number of nympal moulting was mostly four times (55-75%) followed by three times (25-45%), regardless of temperature and food. Percent emergence rate was 52-70%, 48-66% and 22-38% at 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively, showing a tendency to decrease with increasing temperature, and was affected by foods. Adult longevity, when supplied with one food, was 19.8 to 22.5 days at 24$^{\circ}C$, 15.6 to 17.0 days at 28$^{\circ}C$, and 10.3 to 11.7 days at 32$^{\circ}C$. There was no significant difference among foods in terms of adult longevity, but it tended to be slightly longer when provided with four foods than with one food. Number of eggs predated by an adult, when supplied with one food, was 35.7-54.2, 31.6-44.6 and 18.1-28.2 at 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively. It was highest on BPH, followed by SBPH, WBPH and GLH regardless of temperature. Number of egg Predated by an adult, when supplied with four foods, was 4.0-28.9, 2.9-29.0 and 17-13.6 at 24$^{\circ}C$, 28$^{\circ}C$ and 32$^{\circ}C$, respectively, and was significantly different among foods supplied. The results suggest that the significantly different predation amount by adult was due to food preference amoung the different foods.