This study was performed to investigate the correlation between changes of feeding behavior of green peach aphid, Myzus persicae and residual effect of an insecticide, Pyrifluzuinazon, using EPG technique. Pyrifluquinazon was showed the insecticidal activity until three days (72h) after treatment, and the activity was high in nymph than adult of GPA. There was no difference among treatment methods. Lethal sign was observed the slimed the abdomen of GPA after 3 days that rises the insecticidal activity, and dieㅇ as being sticked and/or pulled out the needle. Residual efficacy from 1, 3, 5, 7 to 20 days after treatment, insecticidal activity was showed 70% in 50 ppm, recommended concentration, until 5 days. And waveforms relating to non-probe time and phloem phase time using EPA, feeding inhibition efficacy was showed during 5 days after treatment, but showed similar level with control after 13 days. These results show that the change of feeding behavior of GPA is correlated with the change of residual effect of pyrifluzuinazon.

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.

Deciduous tree fruits such as pears and apples are widely grown in the Pacific Northwest of the United States and are well adapted to the seasonal environment in that region. Extended cold periods provide adequate chilling to break dormancy and reinitiate growth in the spring. Cold exposure synchronizes the physiological processes and makes sure that bloom is uniform and that fruit matures in a uniform manner. As a result of global warming, some fruit-growing areas may experience inadequate cold exposure during the winter months, gradually shifting the southern boundary for production of deciduous fruits further north. However, climate change will affect not only growth and fruiting habits of fruit trees but also the insect and mite pests which feed on them. There is general agreement that in temperate regions a trend towards warmer summers and milder winters will generally benefit insect and mite pests and increase their injuriousness. Temperature changes in particular will impact the development, mortality, phenology, and voltinism of fruit pests. Here we discuss how climate change may affect pests and control practices on deciduous tree fruits in the Hood River Valley of northern Oregon. This small valley extends in a north-south direction from the Columbia River to the foothills of Mt. Hood and is characterized by a varied topography and large altitudinal differences (sea level to 600 m). The major pest of pears and apples in that area is codling moth, Cydia pomonella L., a cosmopolitan pest which is present in most deciduous fruit-growing areas of the world. Like its host trees, the codling moth is well adapted to a seasonal environment. Diapause is the principal mechanism which synchronizes its phenology with the tree and the presence of fruit, the larval food source. Diapausing overwintering larvae require cold exposure (chilling) to terminate diapause in late winter or early spring. At the lower elevations close to the Columbia River the codling moth is bivoltine but gradually becomes univoltine at the higher elevations where the growing season is shorter and fewer heat units (above 10oC) are available for development. Long-term temperature records from the lower Hood River Valley indicate that the 25 years since 1985 have been considerable warmer than the 25 years prior to 1985. For instance, the average heat units available for codling moth development over a season have increased by more than 10% over the last 25 years. The codling moth is adapting to this warming trend by gradually increasing its voltinism (number of generations). As a result, the severity of codling moth as a pest can be expected to increase. Therefore, fruit growers will have to adjust and intensify control practices to keep fruit free from codling moth damage. We will also explore how other fruit and foliage feeding pests which are part of the pest complex of pears and apples in northern Oregon fare under different global warming scenarios compared to codling moth.