• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.155-162
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• 2002

Cytochrome P45O (CYP) gene has been known to play one of the most important roles in metabolizing the exogenous materials. In insect, CYP is particularly known to detoxify toxic materials by adding oxygen molecule to the hydrophobic region of the materials. Thus, CYP-dependent metabolism is associated with the adaptation of insect to host plant chemicals. This in turn is known to be one of the driving forces for CYP diversification. In the present study, we cloned seven gene fragments of CYP 4 (CYP4) family from the midgut of the beet armyworm, Spodoptera exigua, through RT.PCT, Sequence analysis of the product showed the gene fragment to contain an open reading frame of ~150 amino acids, consisted of ~450 bp. The cloned gene fragments contained typical, conserved regions found in CYP4 family. Pairwise comparison of the deduced amino acid sequences among seven clones ranged in divergence from 0% to 52.86% and resulted in five distinct clones. The other two clones were identical or differ by one amino acid respectively to the corresponding clone, although each differed by ten nucleotides. Analysis of correlation between GenBank-registered, full length CYP4 and the cloned fragments resulted in statistically significant relationship ($r^{2}$ = 0.96085; p < 0.001), suggesting utility of the partial sequences as such full-length sequences. Phylogenetic analysis of the clones with GenBank-registered insect and mammal CYP4 family sequences by parsimony and several distance methods subdivided the clones into two groups: tones belonging to CYP4S and the others to CYP4M families.

• The Korean Journal of Pesticide Science
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• v.19 no.4
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• pp.411-417
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• 2015

This study is conduced to investigate control efficacy of mixture of plant extracts which has been reported to control pest and Bacillus thuringiensis or alone. Control efficacy of 0.025% matrine or mixture of 0.016% matrine and BT ($5{\times}10^4cfu$) against $3^{rd}$ instar larvae of beet armyworm were best as 98.7% and 93.3%. Treatment of mixture of 0.01% matrine and BT ($5{\times}10^4cfu$) showed the mortality of 69.3%. In the case of neem, when the mixture of 0.1% neem and BT was applied to larvae of S. exigua, their mortality was 50.0% and weight of larvae were significantly different compare with control and only neem treatment. Therefore For effective control reducing population of beet armyworm and possibility to develop resistance against BT and eco-friendly agents, mixture of 0.016% Matrine and BT ($5{\times}10^4cfu$) could be used.

• The Korean Journal of Pesticide Science
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• v.13 no.3
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• pp.197-202
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• 2009

Based on the insecticidal efficacy by insecticide treatment methods, neurophysiological responses were compared with the larvae of diamondback moth (DBM) and beet armyworm (BAW) using pyrethroids working on nervous system. By body spray method, all pyrethroids were showed lower insecticidal activity below 50% on the larvae of DBM and BAW. By leaf dipping method, DBM larvae were showed the insecticidal activity as 100% at 50 ppm deltamethrin, 80.0% at fenvalervate and 63.3% at permethrin. However, BAW larvae were showed lower insecticidal activity as similar as control in all concentration. In order to examine electrophysiological response on nervous system on DBM and BAW larvae when treated three insecticides, we investigated the voltage and reaction degree. The voltage of DBM were responded as high as $10^{-7}M$ in deltamethrin, $10^{-5}M$ in fenvalerate and $10^{-3}M$ in permethrin. However, those of BAW were showed dull responses with small variation of voltage to all three insecticides.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.45-50
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• 2008

For the development of friendly environmental control of the beet armyworm, Spodoptera exigua that is too hard to control in the field, 25 insecticides were chosen from 58 registered to the beet armyworm, and bioassayed. There are 12 insecticides with neurotoxical activities, 10 with insect growth regulators and 3 Bacillus thuringiensis products. Among 12 insecticides with neurotoxical activities, mortality of S. exigua was 100% with emamectin benzoate (EC) and indoxacarb (WP) within 3 and 5 days after application, respectively. Otherwise, WG and SC of indoxacarb, Indoxacarb + etofenprox (WP) and pyridalyl (EW) were showed up to 91 %. Methoxyfenozide + spinosad (SC) was better than any other insect growth regulator as 100% mortality within 3 days after application. And methoxyfenozide (WP), tebufenozide (WP) and methoxyfenozide (SC) were 92% by 5 days. However, 3 kinds of B. thuringiensis products were showed under 35% mortality within 5 days from first spray.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.145-149
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• 1997

Occurrence pattern of major insect pests on 7 recommended potato cultivars in Korea was investigated from sowing to harvesting time at Kangneung and Daegwallyung experiment fields in 1996. Green peach aphid (Mym persicae Sulzer), potato aphid (Macrosiphum euphorbiae Thomas) and beet armyworm (Spodoptera enigua Hubner) were the major insect pests on potato leaves, and wireworm (Selatosomus puncticollis Mot.) was the major pest on tubers. There was a slight difference of average number of aphids per 50 leaves among cultivars; ranged from 22.7 on cv. Dejima to 46.3 on cv. Superior. Numbers of leaves damaged by beet armyworm larvae on cv. Shepody and cv. Jopung were 11.0 and 14.3, and these cultivars are thought to be resistant against the larvae infestation. However, degree of damage on cv. Dejima and cv. Namsuh was higher 10 times than cv. Shepody and cv. Jopung. In wireworm, the percentage of damaged tubers on cv. Irish Cobbler was lowest of 8.1%, and followed by cv. Superior, cv. Dejima, cv. Jopung, and cv. Atlantic. Whereas, those on cv. Namsuh and cv. Shepody were significantly high of 50.0% and 46.8%.

• Korean journal of applied entomology
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• v.36 no.2
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• pp.172-178
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• 1997

There was a great variation in insecticide susceptibilities among field and laboratory populations of the beet armyworm, Spodoptera exigua (Hiibner). Unselected laboratory population, which had been reared for 6-7 generations in our laboratory without exposure to insecticides, was more susceptible than its parental field population in all tested insecticides. Two selected laboratory populations with parathion or deltamethrin showed much higher insecticide tolerance than did the unselected laboratory population in their own selection insecticide. The variation of the insecticide susceptibilities was highly correlated with esterase and acetylcholinesterase activities. Field and the selected laboratory populations had lower acetylcholinesterase activities and higher esterase activities than did the unselected laboratory population. Acetylcholinesterase of the field and the selected laboratory populations had higher Km values than did that of the unselected. In a population, Km values were varied among different developmental stages; acetylcholinesterase of the fifth instar larvae had the highest Km value among those of the other larval stages. Twenty one esterase bands were separated on 6.5% nondenaturing polyacrylamide gel from the whole body extracts of the fifth instar larvae. E2, E7, E8, Ell, El6, and El7 esterase bands were developed more frequently in the insecticides-selected populations than in the unselected population. These results suggest that the variation of insecticide susceptibilities of the beet armyworm includes both biochemical mechanisms: target site insensitivity and enhanced activity of detoxification enzyme.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2004.05a
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• pp.169-169
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• 2004

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2000.10a
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• pp.43-43
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• 2000

• Proceedings of the Korean Society of Sericultural Science Conference
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• 2001.04a
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• pp.67-67
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• 2001

No Abstract. See Full-text

• Korean journal of applied entomology
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• v.39 no.3
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• pp.199-205
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• 2000

The field control efficacy of entomopathogenic nematode, Steinernema carpocapsae Weiser, was evaluated on the beet armyworm, Spodoptera exigua (Hiibner). The insect pest has been known to be a defoliator at the aerial part of the crop and difficult to be controlled effectively with most commercial chemical insecticides due to its insecticide resistance. To overcome the susceptibility of the nematodes to desiccation when they were applied by leaf spray in field condition, we screened several commercial antidesiccants (alkyl glucoside, CMC, glycerol, Keltrol-F, Kunipia-G, and Laponite LXG) optimal for survival of the nematodes. Keltrol-F (0.1 %) was selected as a candidate supplement for field application of the nematodes. Leaf spray of the nematodes at 5,000 infective juveniles/ml of distilled water containing 0.1 % Keltrol-F resulted in 87.7% control efficacy on the 3rd instar larvae of Sp. exigua.