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Park J.,Sungkyunkwan University | Jahan S.M.H.,Kyungpook National University | Song W.-G.,Kyungpook National University | Lee H.,Sungkyunkwan University | And 6 more authors.
Journal of Asia-Pacific Entomology | Year: 2012

Bemisia tabaci is a species complex that consists of at least 24 genetically diverse biotypes. Here, we determined the biotypes of 27 populations collected in 17 different regions of Korea. Nucleotide sequence comparisons of cytochrome oxidase showed that 26 populations were Q biotype and that one population, the Goyang population, was B biotype. Further subgroup analysis of the Q biotype showed that all populations belonged to the Q1 subgroup, which originates from Western Mediterranean countries. Five endosymbiotic bacteria from various B. tabaci populations were analyzed by comparing rDNA sequences. Hamiltonella was detected in all the populations tested regardless of biotype. Cardinium was detected in all Q biotype populations but not in the B biotype population, while Rickettsia was detected in the B biotype population but not in Q biotype populations. Arsenophonus and Wolbachia were detected in 35% and 58% of Q biotype populations, respectively, but not in the B biotype population. Our results show that the endosymbiont profile is strongly associated with each biotype and with subgroups of the Q biotype. Survey of TYLCV disease from 2008 to 2010 indicated that this disease is widely spread in Korea. This study suggests that the rapid spread of TYLCV may be associated with endosymbiont infection, particularly Hamiltonella infection of B. tabaci. © 2011 Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society. Source

Dang Q.L.,Korea Research Institute of Chemical Technology | Dang Q.L.,Chungnam National University | Lee G.Y.,Environmental Agriculture Research Division | Choi Y.H.,Korea Research Institute of Chemical Technology | And 7 more authors.
Crop Protection | Year: 2010

Several organic solvent extracts of Chenopodium ficifolium were tested for their insecticidal activity against melon and cotton aphid, Aphis gossypii, on cucumber plants. Both methanol and ethanol extracts, at 5000 μg ml -1, were highly active giving over 80% control. The other crude extracts displayed moderate or weak insecticidal activity giving control in the range of 16-69%. Two phospholipids were isolated as insecticidal active substances from C. ficifolium. Their chemical structures were identified as 1-palmitoyl-2-(3-trans)-hexadecenoyl-sn-glycero-3-phosphoglycerol and 1-palmitoyl-2-linoleoyl-3-glycerophosphocholine by GC-MS, EDS, mass and NMR spectral analyses. Both compounds displayed a dose-dependent mortality of A. gossypii. Furthermore, the liquid formulation that was obtained by partitioning with n-hexane from the methanol extract of C. ficifolium controlled melon and cotton aphid on cucumber plants effectively. These results indicate that extracts of C. ficifolium have potential for development as botanical insecticides for controlling A. gossypii infesting cucumber plants. © 2010 Elsevier Ltd. Source

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