• Korean journal of applied entomology
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• v.50 no.3
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• pp.171-178
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• 2011

Bacillus thuringiensis (Bt) is a bacterial biopesticide against insect pests, mainly lepidopterans. Spodoptera exigua and Plutella xylostella exhibit significant decreases in Bt susceptibility in late larval instars. To enhance Bt pathogenicity, we used a mixture treatment of Bt and other bacterial metabolites which possessed significant immunosuppressive activities. Mixtures of Bt with culture broths of Xenorhabdus nematophila (Xn) or Photorhabdus temperata ssp. temperata (Ptt) significantly enhanced the Bt pathogenicity against late larval instars. Different ratios of Bt to bacterial culture broth had significant pathogenicities against last instar P. xylostella and S. exigua. Five compounds identified from the bacterial culture broth also enhanced Bt pathogenicity. After determining the optimal ratios, the mixture was applied to cabbage infested by late instar P. xylostella or S. exigua in greenhouse conditions. A mixture of Bt and Xn culture broth killed 100% of both insect pests when it was sprayed twice, while Bt alone killed less than 80% or 60% of P. xylostella and S. exigua, respectively. Other Bt mixtures, including Ptt culture broth or bacterial metabolites, also significantly increased pathogenicity in the semi-field assays. These results demonstrated that the Bt mixtures collectively names "Bt-Plus" can be developed into potent biopesticides to increase the efficacy of Bt.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2004.05a
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• pp.145-145
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• 2004

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2004.05a
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• pp.175-175
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• 2004

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2002.05a
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• pp.179-179
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• 2002

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2002.05a
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• pp.172-172
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• 2002

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2003.10a
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• pp.64-64
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• 2003

• Korean journal of applied entomology
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• v.30 no.2
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• pp.124-129
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• 1991

This study investigated seasonal occurrence and daily flight activity using synthetic sex pherom mone and injury characteristics of 야et armyworm, Spodoptera exigua in Chonnam area of K Korea in 1990. Male adults were attracted to phermone trap from mid-June to late November w with the peaks at mid-late August, mid-late September and early-mid November in vinyl i house and also were attracted from mid October to late November in field. Primary peak of occurrence in vinyl house was 20 days sooner than field. It seems to have 6 generations a year in C Chonnam region based on the estimation of larval biomass. Daily male flight was active from m midnight to before sunrise with the peak at 4-6 A.M .. In injury characteristics at various host plants, damage was great in early growing stage at below 10 cm of plant height in Allium fistulsum. Chrysanthemum morifolium was damaged at mostly upper part of leaves reaching to m the extent up to 70%. In case of Gypsophila paniculata, plants injured at early growing stage do n not grow and flower normally.

• Korean journal of applied entomology
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• v.34 no.2
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• pp.106-111
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• 1995

This study was carried out to investigate the effect of mass trapping with synthetic sex pheromone on seasonal occurrence of, the Beet amyworm (BAW) Spodoptera exigua, and on suppress of their density in Chonnam province from 1992 to 1994. Adult males of BAW were colllected by the trap from early through early November. The numbers began to increase abruptly from early July, and forming three peaks on mid July, early August and early September. Yearly occurrence and the area damaged by the BAW varied in relation to weather condition. Especially, low temperature and heavy rainfall in August 1993 seems to have affected to reduce the BAW population. The pheromone trap attracted higher numbers (1.5~2.3 times) of BAW adult than ordinary light rap. And the BAW population in vinyl hose was noticeably reduced when more than 10 pheromone traps were operated per 330$\m^2$ of vinyl house.

• Korean journal of applied entomology
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• v.38 no.2
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• pp.145-149
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• 1999

To develop the baculovirus expression vector system (BEVS) adopting p10 gene promoter of Spodoptera exigua nucleopolyhedrovirus (SeNPV), we characterized the p10 gene of SeNPV. The nucleotide sequence of 545 bases including the coding region of p10 gene was determined. Compared with the previously reported SeNPV p10 gene (Zuidema et al., 1993), 4 bases were different in the 5' and 3' flanking region but no difference was found in the coding region. The p10 gene was located within Xho I 1.5 Kb, Sph 1 2.4 Kb and Cla I 4.0 Kb fragments by Southern hybridization analysis. Also, the Sph I 2.4 Kb and the Cla I 4.0 Kb fragments were cloned and their restriction enzyme maps were determined.

• Korean journal of applied entomology
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• v.30 no.1
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• pp.54-57
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• 1991

The width of head capsule of the beet armyworm, Spodoptera exigua (Hubner), was measured on the 5th generation larvae reared with artificial diet. The mean widths of head capsule of each instar were: 1st, 0.246 mm; 2nd, 0.35 mm; 3rd, 0.546 mm; 4th, 0.809 mm; 5th, 1.242 mm; and 6th, 2.185 mm. The coefficient of variation (%) of each instar were: 1st, 8.6; 2nd, 9.5; 3rd, 15.1; 4th, 11.2; 5th, 12.0; and 6th, 12.9. The growth ratio of each instar were: 2nd, 1.43; 3rd, 1.55; 4th, 1.48; 5th, 1.54; and 6th, 1.76. The fitness(%) to Dyar's law of the measurement of head capsule width were: 1st, 94.7; 2nd, 98.3; 3rd, 98.7; 4th, 94.8; 5th, 94.6; and 6th, 92.2. When the logarithm of the width is plotted against the number of instars, the calculated regression line is highly significient (Log Y = -0.819 + 0.1872X, $r^2$ = $0.9977*{**}$) and Dyar's constant was 1.54.