The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is widely utilized for greenhouse pollination in South Korea. Understanding the magnitude of genetic diversity and geographic relationships is of fundamental importance for long term preservation and utilization. As a first step, we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to the “DNA barcode” region and the complete internal transcribed spacer 2 (ITS2) of nuclear ribosomal DNA from 88 individuals collected in nine South Korean localities. The complete ITS2 sequences were longest among known insects, ranging in size from 2,034 bp ~ 2,052 bp, harboring two duplicated 112-bp long repeats. The 658-bp long mtDNA sequences provided only six haplotypes with a maximum sequence divergence of 0.61% (4 bp), whereas the ITS sequences provided 84 sequence types with a maximum sequence divergence of 1.02% (21 sites). The combination of the current COI data with those of published data suggest that the B. ignitus in South Korea and China are genetically a large group, but those in Japan can be roughly separated into another group. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population were found to exist among the South Korean populations of B. ignitus, which suggests panmixia. This finding is consistent with our understanding of the dispersal capability of the species.

Field research was undertaken for recovering mosquito larval mermithid parasite, Romanomermis species in rice fields in 54 different areas in period of May through October, 2009. Of 54 area rice fields surveyed, Romanomermis sp. recoveries were made from 4 areas. 32 Anopheles mosquito larvae, malaria disease vector were infected and died from samples collected in Pochon area, and a total of 10 Culex mosquito larvae, house frequenting mosquito were infected to death in 3 different areas, Gimpo, Sangju and Gurae, respectively. On the basis of positive natural infection record, an intensive host-parasite occurrences and/or population study was surveyed in foci area of Pochon in small pond (P) and Rice paddies (A and B) during 5 months till end of October. The natural mermithid infection was continuously occurred from June through October in weekly samples, however the rate of infection was appeared higher in June-July, thereafter the rate gradually decreased in progress of the season. The highest natural infection rate was observed from the Pond 9.1% followed by Rice paddy "A" 5.2%, Rice paddy "B" 2.4%, respectively. Including 2 other Rice paddies "C" and "D", a total mosquito larvae collected was 3,270, an overall average natural infection rate was recorded as 3.7% (121 Anopheles mosquito larvae infected).

The rice leaf roller, Cnaphalocroci smedinalis Guenée (Lepidoptera: Pyralidae) is a leaf-feeding pest of rice world-widely distributed. For better understanding of the pest insect, geographic sequence variation of the species were performed using the mitochondrial A+T-rich region, with the samples collected from seven Korean and six Chinese localities. A total of 94 haplotypes obtained from 187 individuals showed the length variation, ranging from 339 bp to 348 bp. The maximum divergence of 4.57% appears to evidence a substantial sequence variation, indicating the applicability of this molecular marker to the study of geographic variation. Overall, a high per generation migration ratio (Nm = 3.67742 ~ infinite), a low level of genetic fixation (FST = 0 ~ 0.11969), and no discernable isolated population were noted in the most C. medinalis populations. AMOVA analysis to find out allocation of genetic variability of C. medinalis populations has shown allocation of majority of variation to the within-population, rather than among-populations and between-region, suggesting that the C. medinalis populations in both China and Korea are largely well connected. This result is consistent with current knowledge of the dispersal ability of the species. The structure analysis of the A+T-rich region has shown that the typical structural elements found in other lepidopteran insects also is well preserved in the C. medinalis A+T-rich region (i.e., a poly-T stretch and a microsatellite-like A/T repeat).

The silkworm (Bombyx mori), as an industrial insect, possesses a high economic value. Casual discrimination and accumulated genetic information of silkworm varieties are essential ground for the practical utilization and long-term conservation. In this study, nine available microsatellite loci were successfully genotyped from ~50 silkworm strains preserved in Korea. According to genotyping analysis, we obtained 3 ~ 16 alleles per locus, with an average of 7.4, the observed heterozygosity ranging from 0.04 to 0.98, and the polymorphic information content (PIC) ranging from 0.06 to 0.88, revealing that some loci are highly variable. Among 54 strains 13 strains were casually identified by the presence of 17 strain-specific apomorphic alleles. Furthermore, 30 among remaining strains contained strain-specific allele combinations that are also apomorphic to each strain, allowing us to discriminate each of these from other strains by genotyping of multiple loci. These results collectively suggest that the silkworm microsatellite DNA is actually and potentially important molecular marker for the discrimination of the silkworm strains that are preserved as hundreds in Korea, as more loci are genotyped.

The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is one of the most notably utilized for greenhouse pollination in Korea. In order to understand the nature of genetic relationships, gene flow, and population structure of the species we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to “animal barcode” region and the complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA (nrDNA) collected from Korean localities. Although the 658-bp long mtDNA sequence provided only six haplotypes with the maximum sequence divergence of 0.61% (4 bp), the ITS sequences provided 84 sequence types with the maximum sequence divergence of 1.02% (21 sites), confirming better applicability of the ITS sequences to the study of intraspecific variation. The complete ITS2 sequences of B. ignitus were shown to be longest among known insects, ranging in size from 2,034 bp ~ 2,052 bp, harboring two duplicated repeats. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population/ population group were noted to exist among populations of B. ignitus on the basis of both molecules, thus suggesting that the B. ignitus populations on the Korean peninsula are panmictic, which is consistent with our understanding of the dispersal capability of the species

Diamondback moth (Plutella xylostella L.) belonging to genus Lepidoptera is a notorious pest of cruciferous crops worldwide. We evaluated the bioinsecticidal activity of the liquid cultures (LB and NB) of a bacterial strain, Serratia sp. EML-SE1, isolated from a diseased diamondback moth. The pathogenicity of a bacterial strain to diamondback moth was confirmed by the following procedures: treatment of liquid culture on cabbage leaves, ingestion of inoculated cabbage and mortality response. For the test, twenty 3rd instar larvae of diamondback moth were placed on the Chinese cabbage leaf in a round plastic cage (Ø 10 × 6 cm) and sprayed with the liquid cultures. After 72 hours, insecticidal activity of LB and NB cultures of Serratia sp. against P. xylostella larvae showed 91.7% and 88.3%, respectively. In addition, the bioinsecticidal activity on potted cabbage with 14 leaves in a growth cage (165 × 83 × 124 cm) also was similar to that of plastic cage experiment. Summarized, the Serratia sp. EML-SE1 may be a potent candidate as a bioinsecticidal agent to control diamondbac kmoth.

In order to understand the nature of population genetic structure of the notorious pest insect, Spodoptera litura (Lepidoptera: Noctuidae), a total of 159 individuals of the tobacco cutworm collected from six Korean and five Chinese localities were cloned and sequenced their mitochondrial A+T-rich region. A total of 90 haplotypes ranged 324 bp ~ 372 bp in length and 0.30% ~ 4.85% in sequence divergence. Compared to the preliminary mitochondrial COI gene sequence data that provided nearly identical sequences in all samples, the A+T-rich region provided substantially high sequence variation, validating the applicability of this molecule to the study of intraspecific variation. Overall, a very high per generation migration ratio (Nm = 5.91 ~ infinite), a very low level of genetic fixation (FST = 0 ~ 0.077796), and no discernable isolated population were noted to exist among populations of S. litura, although some significant genetic differentiations were found between several pairs of populations. These results collectively suggest that the S. litura populations in both Korea and China are very well interrelated to each other. The structural analysis revealed that the S. litura A+T-rich region harbored two stretches of the [TA(A)]n sequence, the poly-A stretch, and a stem-and-loop structure that are well found in other lepidopteran A+T-rich region. Furthermore, the region harbors the 13 ~ 19-bp long T stretch and 5-bp long motif that have been suggested to function as a possible recognition site for the initiation of replication of the minor strand of mtDNA also were found.

The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is one of the most notably utilized for greenhouse pollination in Korea. In order to understand the nature of genetic relationships, gene flow, and population structure of the species we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to “animal barcode” region and the complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA (nrDNA) with the individuals collected from Korean localities. Although the 658-bp long mtDNA sequence provided only six haplotypes with the maximum sequence divergence of 0.456% (3 bp, from 91 individuals), but the ITS sequences provided 33 sequence types with the maximum sequence divergence of 0.78% (16 bp, from 35 individuals), confirming better applicability of the ITS sequences to the study of intraspecific variation. The ITS2 sequences of B. ignitus were shown to be the longest among known insects, ranging in size from 2,034 bp ~ 2,045 bp and harbored two duplicated repeats, indicating unusual structure of B. ignitus ITS2 sequences compared with other insect ITS sequences. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population/population group were noted to exist among populations of B. ignitus on the basis of both molecules, thus suggesting that the B. ignitus populations on the Korean peninsula are panmictic, which is consistent with our understanding of the dispersal capability.

Eumenis autonoe, a member of the lepidopteran family Nymphalidae (superfamily Papilionoidea) is an endangered species, and is found only on one isolated remote island, Jeju in South Korea, on Halla Mt., at altitudes higher than 1,400 meters. In this study, we report the complete mitochondrial genome (mitogenome) of E. autonoe. The 15,489-bp long E. autonoe genome evidenced the typical gene content found in animal mitogenomes, and harbors the gene arrangement identical to all other sequenced lepidopteran insects, which differs from the most common type found in insects, due to the movement of tRNAMet to a position 5’-upstream of tRNAIle. As has been observed in many other lepidopteran insects, no typical ATN codon for the COI gene is available. Thus, we also designated the CGA (arginine) found at the beginning of the COI gene as a lepidopteran COI starter, in accordance with previous suggestions. The 678-bp long A+T-rich region, which is second longest in sequenced lepidopteran insects, harbors 10 identical 27-bp long tandem repeats plus one 13-bp long incomplete final repeat. Such a repeat sequence has been, thus far, only rarely detected in lepidopteran mitogenomes. The E. autonoe A+T-rich region harbors a poly-T stretch of 19 bp and a conserved ATAGA motif located at the end of the region, which have been suggested to function as structural signals for minor-strand mtDNA replication.

Root knot nematode species, such as Meloidogyne hapla, M. incognita, M. arenaria and M. javanica are economically most notorious nematode pests, causing serious damage to the various crops throughout world. In this study, DNA sequence analyses of the D1-D3 expansion segments of the 28S gene in the ribosomal DNA were conducted to characterize genetic variation of the four Meloidogyne species obtained from Korea and United States. PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism), SCAR (Sequence Characterized Amplified Region) marker and RAPD (Random Amplification of Polymorphic DNA) also were used to develop the methods for exact and rapid species identification. In the sequence analysis of the D1-D3 expansion segments, only a few nucleotide sequence variation were detected among M. incognita, M. arenaria, and M. javanica, except for M. hapla. The PCR-RFLP analysis that involves amplification of the mitochondrial COII and lrRNA region yielded one distinct amplicon for M. hapla at 500 bp, enabling us to distinguish M. hapla from M. incognita, M. arenaria, M. javanica reproduced by obligate mitotic parthenogenesis. SCAR markers successfully identified the four root knot nematode species tested. We are under development of RAPD primers specific to the three root knot nematodes found in Korea.

whitefly, Bemisia tabaci (Gennadius) have a wide host range including cucumber, tomato, and pepper, resulting in loss of crop yield. In this study, we tested larvicidal efficacy of several on-the-market environment–friendly agricultural materials (EFAM) to select the effective products after the target pests were stabilized in indoor rearing condition. The developmental periods of two whiteflies are as follows: in the case of T. vaporariorum, egg duration is 9.6 days, and nymph is 18.9 days, and in the case of B.tabaci, egg durationis 7.4 days, and nymph is 15.2 days under 25℃ with relative humidity (RH) of 60±5% and a photoperiod of 16L : 8D. The total period of T. vaporariorum as 5 days longer than B. tabaci. Among 22 EFAMs six products showed more than 60% of insecticide efficacy for against T. vaporariorum BTVB, BTVD, BTVG, BTVL, BTVM, and BTVS. On the other hand, seven EFAM products including showed over 60% of insecticide efficacy against B. tabaci BTVD, BTVG, BTVK, BTVL, BTVM, BTVN, and BTVU. In the case of Spodptera litura previously, xxEFAMs were tesed against 2nd instar S.litura, and EFAMs were found to have more than 90% efficacy. Test of these six EFAMs against entire larval stages were performed in this study. Although some of these products showed still more than 90% of insecticidal efficacy against up to 3rd instar larvae, the efficacy of these EFAMs sharply decreased as ages increase, result is less than 60% of efficacy of the products at most. This result indicates the difficulty to control S. litura with the on-the-market EFAMs alone under economic injury level. Collectively, it is required to find more EFAMs and find alternative method to control those insect pests tested in this study.

The bumblebees, Bombus species are valuable natural resources being utilized for greenhouse pollination. Low level of genetic variation of Bombus species has been reported previously. In this study, we sequenced complete internal transcribed spacer 2 (ITS2) of the nuclear rDNA from 100 individuals of B. ardens collected from seven localities in Korean peninsula. The ITS2 sequence of B. ardens is longest, ranging in size from 1,940 bp-1,954 bp among known in insects, which ranges approximately from 241 bp-1,728 bp. The ITS2 sequences have ~51% of C+C content and contain each two 27 bp repeats, 20 bp repeats, 33 bp repeats, and 34 bp repeats at the beginning. Such repeats were not found in other insects. Uncorrected pairwise distance among 96 sequences that were obtained from 100 individuals revealed a maximum sequence divergence of 1.03%. Genetic diversity (π) of each population ranged from 0.007801 to 0.009627, and the lowest diversity was obtained from islet population of Ulleungdo, indicating possibly small, isolation of the population. Significant level of genetic distance was only found when Ulleungdo population was compared to two other mainland populations. Except for this, overall, a very high rate of per generation migration ratio (Nm=7.1-infinite) and a very low level of genetic fixation (FST=0-0.06546) were detected between pairs of localities. Analysis of hierarchical relationships among localities consistently revealed no statistically significant structure among populations. Taken these together, the B. ardens populations on the Korean peninsula are panmictic this is consistent with our understanding of the dispersal capability.

To understand geographic genetic variation of the species and relationships among populations of the bumble bee, Bombus ardens, we sequenced a portion of mitochondrial COI gene, which corresponds to "DNA Barcode" region (658 bp) from 101 B. ardens individuals collected over 11 localities in Korea. The sequence data were used to investigate genetic diversity within populations and species, geographic variation within species, phylogeographic relationship among populations, and phylogenetic relationship among haplotypes. A total of nine haplortpes were found, but they very close to each other (a maximum sequence divergence of 0. 304%). Summarized, overall moderate to low genetic diversity within populations and species was characteristic, concordant with the high potential to disperse of B. ardens in Korea. There was no clear regional subdivision was observed and relatively high rate of gene flow among localities and low FST was characteristic.