• 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.

• Journal of Applied Biological Chemistry
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• v.60 no.3
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• pp.271-277
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• 2017

Ethyl formate has been used for the control of insect pests by fumigation. However, there were not many reports to show its target site of fumigant toxicity on insect pests since its first use in the agricultural industry. In the present study, we showed the presumable target sites of ethyl formate fumigation in insect pests using Myzus persicae nymphs. After ethyl formate fumigation, the nymphs of this species were collected and the changes at the biochemical and molecular level were determined. The activity of cytochrome c oxidase (COX) was approximately two-fold higher after ethyl formate fumigation. In addition, the expression levels of acetylcholinesterase (AChE) decreased gradually with increasing ethyl formate concentration. These two findings suggested that COX and AChE might be the major target sites of ethyl formate fumigation. In addition to these results, the analysis of lipid content using MALDI-TOF MS/MS identified 9 phospholipids differently generated 2-fold higher in the ethyl formate-treated nymphs than that in the control nymphs, thereby leading to changes in cell membrane composition in M. persicae nymphs. Therefore, the ethyl formate fumigation caused lethal effects on M. persicae nymphs by changing COX activity, AChE gene expression, and phospholipid production.

• Korean journal of applied entomology
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• v.28 no.2
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• pp.61-68
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• 1989

To investigate the possibility of the BPH control by systematic application of insecticides, biological effects of buprofezin and isoprothiolane upon the BPH population was evaluated in the laboratory and pot. Both chemicals did not affect the developmental period of the nymphal stage with the applied dosages. When the buprofezin treated instar nymph was developed to the adult, adult's longevity was fairly reduced and such an effect of buprofezin was greater upon the younger instar nymphs. Residual effect of buprofezin was about 30 days in the pot. And it could suppress the BPH population when the younger instar nymphs were dominant age group in the population at the time of treatment. Isoprothiolane was also more effective for the suppression of the BPH population when the younger instar nymphs were dominant at the time of treatment. And it was expected that by buprofezin treatment in July the control effect of isoprothiolane against the BPH population could be maximized when it was treated to control the rice neck blast in late July or early August, because buprofezin could induce the biased population age distribution in which younger instar nymphs were main group at the time of isoprothiolane treatment.

• Life and Agrochemicals
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• s.277
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• pp.36-37
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• 2012

• Life and Agrochemicals
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• s.267
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• pp.30-33
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• 2011

• Journal of the korean veterinary medical association
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• v.23 no.10
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• pp.657-662
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• 1987

• Korean journal of applied entomology
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• v.26 no.1 s.70
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• pp.13-23
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• 1987

This study was conducted to know the effects of temperature conditions on the growth and oviposition of the brown planthopper(BPH), Nilaparvata lugens $St{\aa}l$. Results obtained were to predict the timing of the BPH control by measuring population dynamics of the BPH in response to temperature fluctuations upon migration of the insects in paddy fields. Developmental and ovipositional rates under constant and alternating temperature conditions were observed in a plant growth cabinet. Hatchabilities of eggs of the BPH were the highest at $25^{\circ}C$ and were decreased below or above the optimum temperature. Egg periods were the shortest at $27.5^{\circ}C$ and prolonged with decreasing temperature, but retarded at higher temperature above $30^{\circ}C$. Adult emergence rates were the highest at $27.5^{\circ}C$ and reduced with decreasing temperature, and no adult emerged at $32.5^{\circ}C$ and $35^{\circ}C$. Developmental period of nymph was the shortest at both $27.5^{\circ}C$ and $30^{\circ}C$, but extended with decreasing temperature. Female longevity was increased with decreasing temperature and the male longevity was the shortest at $27.5^{\circ}C$. Preoviposition period was the shortest at $32.5^{\circ}C$, but prolonged with decreasing temperature. It was about 6.5 times longer at $17.5^{\circ}C$ than that at $32.5^{\circ}C$. Number of eggs oviposited per female was the greatest at $25^{\circ}C$, but decreased at the temperature below or above the optimum. Under the same total effective day-degrees, hatchabilty at the alternating temperature was about 10% higher than that at the constant temperature but egg period at the alternating temperature was nearly identical as that at the constant. Under the $22^{\circ}C$ condition, emergence rate was about 8% higher at the alternating temperature than that at the constant, however, at the $28^{\circ}C$, the rate was about 8% higher at the constant than that at the alternating. Nymphal period was about $4{\sim}6$ days longer at the alternating temperature than that at the constant. Under the same total effective day-degrees in adult stage, both longevity and oviposition period were longer at alternating temperature than those at the constant. Number of eggs oviposited per female was also higher at the alternating. Longevities of females reared under $28^{\circ}C$ of constant temperature was the longest no matter what temperatures they were exposed after the emergence. This result seems to be indicating that female longevity is greatly influenced by the temperature to which they were exposed durings immature stages. Preoviposition period was affected by the temperature exposed during the nympal and adult stage whereas the number of eggs oviposited was affected by the temperature during the adult stage only. Based on the results from this study, the developmental threshold temperatures seem to be $14.12^{\circ}C$ for eggs, $14.76^{\circ}C$ for nymphs, $9.62^{\circ}C$ for adults, and $15.95^{\circ}C$ for preoviposition period. Estimated values of the total effective temperature for completing each stage were 141.25 day-degrees for eggs, 167.83 day-degrees for nymphs, 349.64 day-degrees for adults, and 58.60 day-degrees for preoviposition.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2003.10a
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• pp.129-129
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• 2003

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2003.10a
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• pp.74-74
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• 2003

• Korean journal of applied entomology
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• v.59 no.4
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• pp.427-432
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• 2020

The ability of sunflower, bean, green perilla, and sesame to attract Metcalfa pruinosa was tested in both laboratory and field conditions. In the laboratory experiment, sunflowers showed the highest attractiveness to M. pruinosa nymphs and adults. These results were the same as those in the field experiment. Sunflowers showed the highest attractiveness among the four candidates as a trap plant for M. pruinosa, with comparable average attractiveness values for nymphs and adults to those in the laboratory. Young beans also showed high attractiveness to M. pruinosa, albeit lower than those of sunflowers. However, the attractiveness of mature beans was low. Sunflowers consistently (P < 0.05) showed significantly higher attractiveness than that of the other three plants, regardless of plant age. Thus, sunflowers would serve as a good trap plant for both the nymphs and adults of M. pruinosa.