This study was conducted to investigate the optimum additive ratio of barley flour when used instead of cotton seed meal for the cultivation of oyster mushrooms. Mycelial growth was the fastest to 11.4 cm in medium containing 5% barley flour and to 9.0 cm in medium containing 30% barley flour. The mycelial density was slightly lower at 5% and 10% of barley powder addition, but there was no significant difference between the other treatments. The yield of the fruiting bodies was 158 g/850 mL, which was highest on treatment with 10% barley flour as a substitute for cotton seed meal. However, this was lower on treatments with only barley flour than in the control (156 g/850 mL). The diameter of the pileus and the hardness of stipes were highest with 10% barley flour and 10% in cotton seed meal, respectively. The L value was highest with 10% added barley flour, but the a-value and the b-value were not significantly different between treatments. The pH of the mixed media before inoculation with Pleurotus ostreatus was 4.7–5.0, and the total nitrogen content was 1.7–2.2, which was slightly lower than that of the control. The total carbon content was 44.6–45.0, which was not significantly different from that of the control. However, the content of trace elements such as Cu and Fe was lower than those of the control.

This study examines how small weaving manufacturers in Japan managed to successfully transform their cotton kimono businesses during the phenomenon of the growing popularity of Western clothing in the 1970s, and develop within the Sanbi industrial cluster to become global leaders in the production of high-quality denim and jeans worldwide. Introduction Japanese denim companies are very small but remain competitive due to their quality, compared with Chinese, Mexican, and Turkish companies. Some of these Japanese companies have won the Premier Vision Fabrics Handle Prize, while others have created new denim fabrics, such as soft denim, for luxury brands. According to the data of the Office of Textile and Apparel (OTEXA), as a proportion of sales in 2015 the United States imported most of its blue denim fabric from Japan (28.9 percent), with China in second place (26.2 percent), and Mexico third (17.3 percent); in terms of volume, the United States imported blue denim fabric from China (36.3 percent), with Mexico in second place (24.8 percent), and Japan third (13.5 percent). How was it that Japanese denim companies developed to become such prominent leaders in the field? Most of these companies are clustered geographically, with jeans companies sitting side-by-side with dyeing, processing, and finishing factories. These clusters were originally set up for the production of Kasuri cotton kimono clusters, and only shifted into denim and jeans production in the 1970s. This study will shed light on the development process of the denim industry in Japan – focusing on the Sanbi district, the largest denim and jeans cluster – and will examine the success factors in the global market from a historical perspective using primary sources. The Westernization of Clothing One success factor is the social and culture background in Japan (Fujioka and Wubs, forthcoming). Before the Second World War most people in Japan – male and female, old and young – wore kimonos. A kimono is a traditional Japanese robe that is tied at the waist by a wide belt called an ‘obi’. It has no buttons, zippers, or any other kinds of fastening. The shape of the garment is very simple and it has little decoration. A kimono is made from many different types of fabric, including silk, cotton, wool, and linen. The type of fabric defined the kimono’s suitability for different occasions, such as a high-quality silk kimono for ceremonial events and a cotton one for casual wear. The type of fabric also reflected a person’s social position, until the Meiji Restoration in 1868. During this time only the Samurai class could wear silk kimonos, while other social classes wore cotton kimonos. After 1868 people had freedom of choice in clothing, meaning that anyone could wear silk kimonos for weddings and funerals. Although Western-style clothing had already been introduced to the upper classes by the Japanese government during the Meiji Restoration, after the Second World War, the Japanese lifestyle began to be westernized at an ever-faster pace, particularly in the area of clothing. Along with the high economic growth in the late 1950s and early 1960s, the kimono market shrank and Western fashion became a mass phenomenon in Japan. First came tailor-made clothes for upper-class and upper-middle-class customers; after this, clothing companies rapidly increased their sales, and ready-to-wear clothing soon became common among every generation and income group in the 1970s. Jeans were one example of the clothing that was introduced at this time, and a niche market formed of mainly young customers who lived in urban areas. These young consumers had first seen jeans being worn by Americans from the General Headquarters (GHQ) during the recovery period, and they soon began to identify jeans as a symbol of freedom and individuality. With the increasing demand for jeans, several jeans and denim companies were established in the 1970s to capture this niche market. Since then the denim and jeans market in Japan has developed to specialize in high-quality premium denim and jeans. The Sanbi Industrial Cluster The main factor in the success of the Japanese denim and jeans industry is the effective transformation of the whole cluster. Cotton kimonos have a variety of styles based on various dyeing and weaving methods. The ‘Kasuri’ kimono, for example, is a type of cotton kimono that is dyed with indigo, requiring great skill in dyeing and weaving; as a result, it can be very expensive, although this type of cotton kimono is still regarded as casual, everyday clothing. There were three main industrial clusters for Kasuri kimonos in Japan, namely Kurume, Iyo, and Bingo, which had been established in around 1800. Among these, Bingo became the largest cluster and produced more mass products than the others in the 1960s. While Kurume and Iyo were striving to innovate a new Kasuri fabric and shifted to the high-end market to cover the decreasing demands of kimonos, the Bingo cluster created mass products more efficiently than before. It continued to increase its sales until 1960 with the improvement of technology, although in the 1970s sales began to decrease rapidly with the huge growth in demand for Western clothing (Shinichi Choshi Hensan Iinkai, 2002). Many manufacturers therefore suffered from the introduction of the new Western clothing. Some silk kimono manufacturers were able to shift their focus to the high-end market for ceremonial occasions due to their special place in Japanese society (Hashino, 2015). However, many cotton kimono manufacturers, particularly those in the Bingo cluster who focused on mass customers, were unable to do so, because of the shrinking casual kimono market. This industrial cluster was therefore forced by changing consumer demands to transform the whole nature of its business from the production of traditional cotton Kasuri kimonos to a brand new industry. The neighboring clusters of Bingo are Bizen and Bicchu, which were also cotton kimono clusters that used Kasuri fabric. Some manufacturers in Bizen who made kimono accessories started to produce ‘tabi’ (Japanese-style socks) in 1877 and then began sewing Western-style work clothes in the 1910s. In the 1920s many manufactures in the Bizen cluster started to produce Western-style school uniforms, which became increasingly popular (Fujii et al., 2007). This was a natural transition in terms of finding different uses for the same relevant technology: from the production of cotton fabric to tabi, and from tabi to school uniforms. All these products were made for daily use, and the same cutting and sewing skills for thick textiles that were used to make tabi were directly transferable to the production of work uniforms and school uniforms; by 1937 the Bizen cluster had become the largest producer of school uniforms in Japan. However, between 1965 and 1970 the demand for school uniforms fell, because the early generation of baby boomers had passed through school, and competition within each cluster became more intensive with the emergence of newcomers. In order to manage the distribution channel and build a stable production system, large cotton-spinning companies controlled the weaving mills and sewing factories and organized retailers to maintain retail prices. This was a well-known form of management in Japan at the time called ‘Keiretsu’. As a result, those manufacturers who were not working in partnership with any large spinning manufacturers found it very difficult to secure orders, and were eventually pushed out of the industry and forced to change the nature of their business. One of these small manufacturers in Bizen was called Big John, which had been established in 1940 to produce school uniforms. After transforming its business, it started to sew the first ‘made in Japan’ jeans using imported American denim in 1967, and later using Japanese denim in 1972 (Sugiyama, 2009). Its great success encouraged many of its surrounding manufacturers to join this emerging field, which resulted in the establishment of a whole new denim and jeans industry that spread across Bizen, Bingo, and Bicchu to the point where these three districts became collectively known as ‘Sanbi’ in Japanese. The Successful Transformation of Industrial Clusters New technology for producing denim and jeans was brought to Japan from the United States. Many denim companies started out as producers of Kasuri fabric and shifted to denim production in the 1960s and 1970s, using their existing skills and technology to make this transition. Although it was a natural path to take considering the change in consumer demand and the fact that both Kasuri fabric and jeans were dyed by indigo, there were many challenges involved in adapting to this change. Rope dyeing was the biggest hurdle that these manufacturers had to face, but they managed to learn the technique by reverse engineering American-made jeans and relying on their skills in indigo dyeing and sewing thick textiles. Making a success of this transition from a cotton kimono cluster into a denim and jeans cluster was the only way that these businesses could survive the huge growth in popularity of Western clothing in Japan. This whole transformational process was led by small, lesser-known manufacturers rather than by larger ones. As one of the major businesses in the Kasuri cluster in Japan, Bingo catered for the mass market, but was hardest hit by the introduction of Western clothing, as it was more difficult for its business model to adjust to westernization. Bizen, however, managed to shift to the production of Western clothing at an early stage, focusing on uniforms – and it was the dropout factories from the uniform industry that eventually became the driving force behind the emergence of the jeans industry. The resulting success of the Japanese denim business model then spread out across the cluster, which today enjoys an enhanced competitive advantage in the global market.

Entomopathogenic fungi have been used as important part of integrated pest management program to control aphid. In particular, Beauveria bassiana was distributed throughout the world including temperate and tropical area, various habitats from alpine soil, desert soil to running water and both insect and plant. Especially the fungus has also been isolated from the surface and the interior of plants and act as natural control agent. Viability of fungi on the plant surface may be influenced by temperature, humidity, sunlight and plant type as well as fungal isolate. Persistence of treated fungal control agent on phylloplane and control efficacy may differ from environmental conditions and isolates. In this study, we investigated the persistence of an B. bassiana which is developing as prototype wettable powder to control cotton aphid, and the residual efficacy of the prototype on cucumber under three different greenhouse conditions.

The cotton bollworm, Helicoverpa armigera (Hübner) is a serious agricultural pest which has evolved resistance against many chemical classes of insecticides. This species has evolved resistance to the synthetic pyrethroids across its native range and is becoming a truly global pest, after establishing in Brazil and having been recently recorded in North America. A chimeric cytochrome P450 gene, CYP337B3, has been shown to detoxify to fenvalerate and cypermethrin. The CYP337B3 gene has now been detected in different populations around the world, and is even found in South America. This gene is likely to have arisen independently in different geographic locations, probably through selection on pre-existing diversity, and there is ongoing movement of these alleles around the world. The alleles found in Brazil are those most commonly found in Asia, suggesting a potential origin for the incursion into the Americas. This information should be taken into account when devising control strategies for this invasive pest, both in its native range and in the Americas

Cotton aphid, Aphis gossypii Gloever is one of the major pests on a wide range of economically important crops in the world. The sustained use of chemical insecticides to control the aphid has led to the emergence of resistant strains to numerous used insecticides. As an alternative strategy entomopathogenic fungi have been used as part of integrated pest management program to control aphid, especially insecticide-resistance population. In particular, Beauveria bassiana-based commercial bio-insecticide has been used to reduce the pest population under greenhouse conditions in various countries. In this study, we investigated the control efficacy of a prototype of commercial mycopesticide using an B. bassiana (wettable powder) against cotton aphid on potted cucumber plant in greenhouse conditions.

This study investigated the characteristics of cotton production of Damyang-gun & Hwasun-gun, Yeongsan River compared with that of Gurye-gun, Seomjingang River in modern times. To do this, research method was both literature and fieldwork research, results were as follows. First, as for cotton fiber cultivation in Damyang-gun & Hwasun-gun, Chinese cotton (在來綿) has been cultivated during Japanese Colonial era unlike Gurye-gun. Especially, Yellow cotton (黃綿) has been cultivated in Hwasungun. Second, as for spinning in Damyang-gun, Hwasun-gun and Gurye-gun, some of cotton spinning process have been gradually changed to mechanization by market shop equipped with mechanized cotton gin and cotton whipping tool since Japanese colonial era. Third, the loom types also, like spinning tools, have been changed from the traditional Korean back-strap loom to the treadle loom in Damyang-gun, Hwasungun and Gurye-gun. Chemical dyeing with chemical dyestuff also has been done since Japanese Colonial era. Fourth, since the 1970s, the outputs of cotton production have been reduced in both Damyang-gun & Hwasun-gun. For Damyang-gun, this has been connected with bamboo craft since the Joseon Dynasty period. So, Damyang-gun has more concentrated on bamboo craft than cotton production. For Hwasun-gun, since Japanese Colonial era, sericulture has been very important. So, Hwasun-gun also has more concentrated on sericulture than cotton production. The main reason to discontinue cotton production in Damyang-gun, Hwasun-gun and Gurye-gun was related to the local choice like economic added value.

Glucose-regulated protein 78 (GRP78) is a member of the heat shock protein 70 (HSP70) family that is specific to endoplasmic reticulum (ER). It is known as chaperones and signaling regulators that respond to ER stresses in vertebrates. However, its function in invertebrates, including insects, is uncertain. Here we determined a full cDNA sequence and the expression patterns of grp78 of Aphis gossypii, which is a major pest of numerous crop plants worldwide. Its cDNA had highly conserved motifs of the HSP70 family and the C-terminal motif of KDEL characteristic of ER-specific HSPs. It showed 98.5% identity with the GRP78 of the pea aphid Acyrthosiphon pisum. Real-time RT-PCR analysis showed that the grp78 level was higher in the fourth instar nymph than in the younger instar and adult stages. Its level was not affected by thermal stress of 10 to 40°C for 1 h. The grp78 level was proportional to the ingestion of a sucrose solution ranging in concentration from 0% to 30% in a Parafilm feeding chamber. In addition, the grp78 level varied among aphids feeding on leaves from 14 different host plants for 24 h; it was higher with eggplant and pepper but lower with pigweed and tobacco than any other plants. Our study suggests that the grp78 level is regulated by nutritional condition of A. gossypii.

This research examined the effect of social media marketing on college students’ behaviors toward cotton clothing. The results showed that social media marketing had a greater impact on college students than conventional marketing or no marketing. Fashion brands should utilize social media to communicate with college students more effectively.

Cellulose is the most useful feedstock in the world that could be used to prepare new kinds of materials, and cellulose derivatives have potential application as functional polymers. Due to the present of hydroxyl groups, cellulose is considered to be an excellent material for surface modification. Among the chemical modification method, Graft copolymerization is a well-established and commonly used technique for modification of polymer surface. In this study, sulfonated GMA-g-cellulose ion exchange fibers were synthesized by gamma-ray mutual radiation. The conversion of epoxy groups into the functional groups was investigated. Factors affecting on grafting process such as radiation dose, monomer concentration, added salt and cross-linking agent were studied.

Cotton aphid infests more than 700 plants and a major pest of various horticultural crops worldwide. The glucose regulated protein 78 (GRP78) is a member of heat shock protein 70. Its expression is associated with the nutritional changes as well as environmental stresses. The full sequences of grp78 cDNA of Aphis gossypii was determined. It had conserved motifs of hsp genes and terminated in KDEL which is common to GRP78. Quantitative realtime PCR showed that its level was changed during development and also upregulated by starvation. However, its level was not much changed by heat stress. The level of grp78 can be use to understand nutritional physiology on insects.

The melon and cotton aphid Aphis gossypii Glover (Hemiptera; Aphididae) is one of the most serious pests worldwide. We surveyed insecticide susceptibility in A. gossypii field populations to 12 insecticides to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to neonicotinoids. One point mutation was found in the beta1 subunit loop D region of the nicotinic acetylcholine receptor (nAChR) of the imidacloprid-resistant strain. Feeding behavior analysis using an electrical penetration graph showed that sublethal doses of imidacloprid had significant effects on the duration of phloem ingestion. In addition, higher doses of imidacloprid induced contact toxicity rather than inhibition of feeding behavior. Temperature and insecticide are two important factors that affect survival, reproduction and other physiological processes of insects. To determine interactions of temperature and insecticide treatment on susceptible and imidacloprid-resistant strains of A. gossypii, adults were exposed to three temperatures (17, 22, and 28℃) or combinations of three temperatures and imidacloprid (LC20), and the expression of several genes (heat shock protein 70, cuticle protein, cytochrome P450, and elongation factor) were analyzed. Additionally, the effect of electron beam irradiation on development, reproduction, and several gene expression of imidacloprid-resistant and -susceptible A. gossypii were compared.

The movement, survival, and weight gain of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) first instar larvae were studied on CB9, CB10 and SR05 cotton varieties under field conditions. The neonate H. armigera were released on the cotton varieties at the squaring stage of the plants and, after a period of 72 hours, the survival, weight gain, and final location of the larvae were observed. While the different cotton varieties had no effect on the survival and weight gain of the larvae, the release locations on the cotton varieties had a significant influence on the larval survival and weight gain. The larvae fed small squares of the cotton varieties were significantly heavier and showed a higher mortality than the larvae fed leaflets and mature leaves. For the cotton varieties in this study, the larvae released on leaflets showed a significantly higher rate of recovery compared to the larvae released on mature leaves and squares. This study also found that that the larvae on leaflets did not move up or downward unlike the larvae on mature leaves and squares. This information on the foraging behavior of larvae on cotton varieties will assist researchers to interpret field data and thereby help with the development of pest management decisions.

This study investigated the characteristics and changes of cotton and silk textile production in Honam district, especially in Gurye, Jella Province from the 1930s to the 1980s. To do this, research method in this study was both literature and fieldwork research and results were as follows. First, in terms of cotton fiber cultivation of Gurye, Chinese Cotton(在來綿) has been substituted for America Cotton(陸地綿) and additionally, Yellow Cotton (黃綿) has been cultivated in the 1930s. Also, in terms of silk fiber cultivation of Gurye, Joseon Silkworm has been substituted for Japanese Silkworm by inflowing the Japanese mulberry tree. Second, in terms of spinning method, cotton spinning has been conducted at every house by an individual tool from the 1930s to the 1950s and has been gradually changed to mechanization by market shop equipped with mechanized cotton gin and cotton whipping tool. However, there have been no changes in silk spinning method from the 1930s to the 1980s. Third, loom type has been changed from the traditional Korean back-strap loom to the treadle loom between the 1930s and the 1940s. Fourth, dyeing was conducted by chemical dyestuff after weaving. The circulation of textile was done through the joint market by Japan in the 1930s~1950s and has changed to the market sales by producers since the 1950s. Fifth, since the 1970s, the outputs of cotton and silk textile of Gurye have been reduced. This was connected with the westernization and the inflow of the synthetic fiber and cloth in cotton and was related to the changes of the nation policy and silk fiber inflow from the china to the Korean farm villages.

The melon and cotton aphid Aphis gossypii Glover (Hemiptera; Aphididae) is one of the most serious pests worldwide. We surveyed insecticide susceptibility in A. gossypii field populations to 12 insecticides (6 neonicotinoids, 3 pyrethroids and 3 others) to examine resistance ratios. The levels of insecticide resistance were extremely high, especially to neonicotinoids, such as acetamiprid, clothianidin, thiacloprid and imidacloprid. To identify the neonicotinoid resistance mechanisms, we used an imidacloprid-resistant (IMI-R) strain as a model strain. IMI-R showed an extremely high resistance ratio and also cross-resistance to all the test neonicotinoids. However, there was little or no cross-resistance to the other insecticides, including sulfoxaflor. Synergist tests and enzyme activity assays suggested the absence of resistance mechanisms based on enhanced detoxification enzymes, such as cytochrome P450, esterase and glutathione S-transferase. One point mutation was found in the beta1 subunit loop D region of the nicotinic acetylcholine receptor (nAChR) of the IMI-R strain. This R81T point mutation was also found in field populations collected from 5 regions. Therefore, the R81T point mutation was identified as an important mechanism of imidacloprid resistance in A. gossypii.

For replacement of methyl bromide(MB) in Korea, VapormateTM, a gas formulation of ethyl formate(EF) with carbon dioxide, are firslty introduced in import bananas and VivakilTM, a gas formulation of phosphine(PH3) with carbon dioxide, are ready to commercial use in export cut flowers. Their applications are being extended for other import and export commodities. Ethyl formate have been shown to have effectiveness short exposure time(<4hr) but it has a limited application at low temperature for TSM(Two spotted spider mites) due to some phytotoxic to strawberry. Phosphine gas has demonstrated their efficacy to TSM at low temperature but only meets quarantine requirement when applying longer fumigation time(>24hr) to control CA(cotton aphids). We firstly evaluated two MB alternatives, EF and PH3, have enhansive effect within short exposure time(4hr) at low temperature(5℃) for controlling both TSM and CA without any injury to export strawberries.

In terms of aphid species identification, both host plant association and morphological characteristics are crucial factors. However, aphids in the genus Aphis Linnaeus (Hemiptera: Aphididae) often are cryptic in morphology due to their rapid radiation. Moreover, overlapping host plant species can make difficult situation worse. Three cryptic species Aphis gossypii Glover, Aphis glycines Matsumura, and Aphis rhamnicola sp. nov. occur together on the Buckthorn, Rhamnus spp. in the overwintering season in Korea. Due to lacking informative morphological characters and host plant sharing, the new species recently has been recognized as a distinct species. In this study, A. rhamnicola sp. nov. on various host plants was compared with the primary host sharing species, A. gossypii and A. glycines, based on morphological and molecular characteristics. In the results, there were significant genetic differences between three species, despite the high similarities in morphology. Our results provide strong evidence for establishing new species, which seems to be a typical heteroecious species that alternates between only primary host, Rhamnus spp., and various secondary hosts. We describe a new species, A. rhamnicola sp. nov., for apterous and alate vivipara, fundatrix, ovipara, and gynopara, including diagnostic key for host sharing species in genus Aphis.

Physically and chemically activated carbons (ACs) exhibited high adsorption capacities for organic and inorganic pollutants compared with other adsorbents due to their expanded sur-face areas and wide pore volume distribution. In this work, seven steam-ACs with different burn-off have been prepared from cotton stalks. The textural properties of these sorbents were determined using nitrogen adsorption at -196°C .The chemistry of the surface of the present sorbents was characterized by determining the surface functional C-O groups using Fourier transform infrared spectroscopy, surface pH, pHpzc, and Boehm’s acid-base neutral-ization method. The textural properties and the morphology of the sorbent surface depend on the percentage of burn-off. The surface acidity and surface basicity are related to the burn-off percentage. A theoretical model was developed to finda mathematical expression that relates the % burn-off to ash content, surface area, and mean pore radius. Also, the chemistry of the carbon surface is related to the % burn-off. A mathematical expression was proposed where % burn-off was taken as an independent factor and the other variable as a dependent factor. This expression allows the choice of the value of % burn-off with required steam-AC properties.

The cotton aphid, Aphis gossypii Glover is an important sap-sucking pest of many pant, including cucumber and pepper. The objective of the present study was to determine the effects of sublethal concentrations of two insecticides (imidacloprid and flonicamid) and the action mechanisms on the feeding behavior of A. gossypii. The median lethal concentrations (LC50) of imidacloprid and flonicamid for adult A. gossypii were 2.01 and 1.92 ppm, respectively. The sublethal concentrations of imidacloprid were 0.22 ppm (LC10) and 0.82 ppm (LC30), and those of flonicamid were 0.094 ppm (LC10) and 0.56 ppm (LC30). The developmental period of A. gossypii nymphs at LC30 was 3.6 days for both insecticide which shorter than controls (4.2 days). Adult longevities at LC10 and LC30 of imidacloprid were 15.2 and 13.6 days, respectively. Adult longevity at LC10 and LC30 of flonicamid was 11.1 and 9.9 days, respectively. Control adult longevity was 15.5 days. Total fecundity was decreased at both sublethal concentration of two insecticides. Feeding behavior analysis using an electrical penetration graph showed that sublethal doses of imidacloprid and flonicamid had significant effects on the duration of phloem ingestion. However, higher doses of flonicamid induced starvation by inhibition of phloem ingestion and higher doses of imidacloprid induced contact toxicity rather than inhibition of feeding behavior.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid-resistant strain (IR) was over 300-fold more resistant to imidacloprid compared to a susceptible strain (S) as judged by LC50 values. A highly imidacloprid-resistant local field population (L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. To identify differentially expressed genes in IR or L, comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from IR, L and S strains. Futhermore, to search the resistance associated proteins in IR or L, comparative proteome analyses based on 2DE were conducted using total proteins extracted from IR, L and S strains. Few common candidate genes detected among IR and L such as ABC genes. Comparison of the nucleotide sequence of six nicotinic acetylcholine receptor (nAChR) subunit (alpha 1-5, beta 1) genes from IR, L and S strain revealed a point mutation in the loop D region of the nAChR beta 1 subunit of the IR, causing an arginine to threonine substitution (R81T). These mechanisms also reported in Myzus persicae and this amino acid change confers a vertebrate-like character to the insect nAChR and results in reduced sensitivity to neonicotinoids.

Many polyphagous herbivore insects considered as a single species are indeed comprised of genetically differentiated host related races that utilize several unrelated plant families. Aphis gossypii Glover, one of the extremely polyphagous aphid species, has more than 100 host plants distributed worldwide. In Korea, it takes holocyclic life cycle, with a number of primary hosts, which is unusual for other aphid species. However, former population genetic studies on A. gossypii have dealt with the populations from only a few agricultural host plants. In this study, we hypothesized that different primary host utilization may be restricted for certain host races and this may play a key role of the genetic differentiation in this species. We collected the cotten aphid populations from 36 different host plants, 5 primary and 31 secondary hosts including various wild and non-cultivated plants. To determine population genetic structure, we analyzed genetic differentiation among those populations using 9 microsatellite loci. As results, four genetically distinct clusters were verified. Of the five primary host populations, there were significant gaps in genetic differences between Rhamnus-associated group and Hibiscus-associated group, and the other populations were affinitive with the Hibiscus-associated group. Overall, primary host populations have a higher level of genetic diversity than secondary host populations. Several populations associated with secondary hosts such as spiderwort, madder, and Korean lettuce were considerably differentiated in the result of principle component analysis, which nearly showed the species level difference similar to Aphis glycines Matsumura and Aphis sp. ex Rhamnus. Thus, there could be reproductively isolated by the loss of primary hosts, and might be already speciated from A. gossypii