• Bulletin of the Korean Chemical Society
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• v.32 no.spc8
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• pp.3120-3122
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• 2011

• Research in Plant Disease
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• v.15 no.3
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• pp.202-208
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• 2009

The genetically modified leaffolder-resistant (Cry1Ac1) rice plant was evaluated for the changes of resistance by comparing the occurrence of major diseases with a japonica type Korean rice variety, Nakdong which was the mother plant of the transgenic rice event, in greenhouse and field conditions. There was no difference in the occurrence of sheath blight and Helminthosporium blight between the two varieties in the fields. We couldn't find any difference of resistance for fungal blast and bacterial leaf blight by artificial inoculation in greenhouse. There was also no difference in the susceptibility to sheath blight in artificial inoculation tests confirming the results in the fields. The possibility of gene transfer of Bar and Cry1Ac1 from the genetically modified rice plant to naturally infected pathogens such as Fusarium moniliforme and Pyricularia oryzae in the field conditions was tested by PCR. And the possible transfer of those genes by continuous inoculation of Xanthomonas oryzae pv. oryzae and Rhizoctonia solani was also tested. However, we couldn't find any possibility of transfer of the genes in natural and artificial conditions.

• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.327-331
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• 2006

This study was carried out to determine the economic injury level of the rice leaffolder,Cnaphalocrocis medinalis G.. The damage aspects of rice plant (at tilling stage) by leaf folders at different larval density per plant were studied in pot experiment (24 cm in diameter, 18 cm in height). One leaf folder consumed 6-7 leaves during larval stage. The damage by leaf folders was simulated by cutting off 0, 10, 30, 50, 70, and 90% of leaves before and after heading stage July 15th (at panicle initiation stage) and August 15th (at milk stage), respectively. When leaves were cut before the heading of rice, the linear relationships between the leaf cutting rate (X) and each factors of yield (Y) were as following; for grain maturity it was Y = -9.379X + 83.630 ($R^{2}=0.493$),\;Y = 0.139X + 0.490 ($R^{2}=0.925$) for yield, and Y = -4.880X + 81.116 ($R^{2}=0.665$) for head rice. When leaves were cut after the heading of rice, it was Y = -23.0l4X + 83.589 ($R{2}=0.915$), for grain maturity, Y=0.141X + 3.466 ($R^{2}=0.842$) for yield, and Y = -13.795X + 81.964 ($R^{2}=0.898$) for head rice. We found that when leaf cutting after the heading stage caused more damage than before the heading in terms of yield and yield components. Based on theses results the economic threshold level was estimated to be 30% and 7% leaf loss before and after heading stage.

• Proceedings of the Korean Society of Crop Science Conference
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• 2004.04a
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• pp.222-223
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• 2004

• 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.45 no.1 s.142
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• pp.91-95
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• 2006

This paper reports a simple rearing system for Cnaphalocrocis medinalis based on corn seedlings diet. C. medinalis population under this system has been maintained by four stages (egg, young larva-1st to 3rd instar, old larva-4th to prepupa, 3nd adult) at $25{\pm}2^{\circ}C,\;40{\pm}10%$ RH, 3nd 16L:8D photoperiod in a laboratory. We have elaborated a new egg collection method using a polystyrene container $(top\;{\phi}11.3\;{\times}\;bottom\;{\phi}\;{\times}\;H8cm)$ which has made a great contribution in easy collection of eggs and storage of them for long period. Under this system, pupation and adult emergence rate, and pupal weight of C. medinalis population were close to the other reports by com seedling diet, and superior to those by artificial diets. Therefore, this rearing system would be useful in obtaining C. medinalsis population suitable to each specific needs.