• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.293-299
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• 2006

A survey was conducted to find out the major plant parasitic nematode in Chrysanthemum morifolium fields in Korea from May to June in 2005. A genus of Pratylenchus was determined as the most important plant parasitic nematode based on analysis of total 50 samples from 8 cities of chrysanthemum field. Pratylenchus showed 86% occurrence rate and average numbered 1,095 per 200cc soils and 1g root. Five Pratylenchus isolates, 'Muan', 'Masan', 'Tean', 'Gumi', 'Jeongup', were selected for the molecular identification of the species of Pratylenchus, and ITS and D3-28S ribosomal DNA were amplified by PCR. For the ITS, only 'Muan' isolate was differentiated by total 1 kb PCR amplification, which was 200 bp larger than all the other isolates. There was no size variation in amplified D3-28S rDNA and all isolate represented approximately 320 bp of PCR product. Sequence data of D3-28S rDNA were analysed by MegAlign program in DNASTAR software and phylogenetic tree was constructed. Sequence homology was 100% between 'Gumi' isolate and 'Tean' isolate and 'Jeongup' isolate was also close to these isolates by 99.7% sequence homology. 'Gumi', 'Tean' group and 'Jeongup' isolate were determined to be closely related to Pratylenchus vulnus by 96.7% and 96.3% similarity in respectively. D3 sequence of 'Masan' isolate was 100% identical to P. penetrans, and 'Muan' isolate showed 99.7% similarity to P. brachyurus. This result was congruent with the branch divergence pattern shown in phylogenetic tree.

• Korean journal of applied entomology
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• v.49 no.4
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• pp.409-416
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• 2010

An entomopathogenic bacterium, Photorhabdus temperata ssp. temperata (Ptt), suppresses insect immune responses and facilitates its symbiotic nematode development in target insects. The immunosuppressive activity of Ptt enhances pathogenicity of various microbial pesticides including Bacillus thuringiensis (Bt). This study was performed to select a cheap and efficient bacterial culture medium for large scale culturing of the bacteria. Relatively cheap industrial bacterial culture media (MY and M2) were compared to two research media, Luria-Bertani (LB) and tryptic soy broth (TSB). In all tested media, a constant initial population of Ptt multiplied and reached a stationary phase at 48 h. However, more bacterial colony densities were detected in LB and TSB at the stationary phase compared to two industrial media. All bacterial culture broth gave significant synergism to Bt pathogenicity against third instars of the diamondback moth, Plutella xylostella. Production of bacterial metabolites extracted by either hexane or ethyl acetate did not show any significant difference in total mass among four culture media. Reverse phase HPLC separated the four bacterial metabolites, which were not much different in quantities among four bacterial culture broths. This study suggests that two industrial bacterial culture media can be used to economically culture Ptt in a large scale.

• Korean journal of applied entomology
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• v.47 no.2
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• pp.133-139
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• 2008

This study was performed to investigate the immature development period, fecundity, emergence rate and sex ratio of Sclerodermus harmandi against different host insects, Monochamus alternatus, M. saltuarius and Psacothea hilaris. Full grown larvae and pupae of host insects were provided with foods. The mean larval period of S. harmandi female was $29.2{\pm}0.93\;and\;25.1{\pm}0.47$ days in larvae and pupae of M. alternatus, $27.1{\pm}0.41\;and\;26.0{\pm}0.69$ days in M. saltuarius, and $26.3{\pm}0.38\;and\;31.2{\pm}0.24$ days in P. hilaris, respectively. S. hilaris adults were emerged at $12.9{\pm}0.2$ days in female and $11.9{\pm}0.2$ days in male after pupation when hosted M. alternatus pupa. Development period in male showed shorter one day than in female. Success rate of oviposition against different hosts was higher as 98.6 and 97.5% on full grown larva and pupa of M saltuarius. Emergence rate was higher as 90.1 and 87.3% on M. saltuarius larvae and pupae. Sex ratio of emerged S. harmandi adults was approximately 10:1 (Female : Male), females showed higher emergence rate than males. The period until first oviposition after emergence in S. harmandi female was the shortest in $4.6{\pm}0.1$ days on M. saltuarius pupa. When three females of S. harmandi were inoculated on M. saltuarius larva, the number of laid eggs was the highest $62.7{\pm}2.5$ per female.