The two-spotted spider mite, Tetranychus urticae Koch, is an economically important pest of crops of plant grown in the field or greenhouse worldwide. It has recently become a serious problem because of the continuous use of acaricides resulting in resistance among spider mite population. Thus, there is a need to find alternative control measures to suppress spider mite populations. In this study, we report the screening result of pathogenic fungi for the control of spider mite. Initial screenings were performed using 352 isolates of putative pathogenic fungi from Korea soils. As results, 11 strains of acaropathogenic fungi were isolated from 8 cadavers of spider mite supporting fungal conidiation. These isolated were identified as four isolates of Beauveria bassiana (6, 2R-3-3-1, 2R-4-5, 2R-4-7), two isolates of Metarhizium anisopliae (4-2, 2-2), one isolate of Clonostachys rosea 5-2, one isolate of Lecanicillium attenuatum 4-1, one isolate of Pochonia suchlasporia 2R-3-1, one isolate of Aspergillus flavus 7 and one isolate of Isaria lilacinus 2R-4-6 by microscopic examination and genetic sequencing of the ITS region. Based on the screening results, eleven isolates were tested for their virulence against adult spider mites. All fungal isolates were pathogenic to spider mite but mortality varied with isolates. These acaropathogenic fungi may be useful to develop eco-friendly acaricide to control two-spotted spider mite.

Western blot analysis using acetylcholinesterase (AChE)-specific antibody was conducted to determine whether AChE gene (Tuace) duplication actually results in overproduction of AChE in Tetranychus urticae (TuAChE). The protein quantities of TuAChE in seven field-collected mite populations were precisely correlated with the copy numbers. To investigate the effects of each mutation on AChE insensitivity and possible fitness cost, eight variants of TuAChE were in vitro expressed using the baculovirus expression system. Kinetic analysis revealed that the Ala391Thr mutation did not change kinetic properties of AChE, whereas the Gly228Ser and Phe439Trp mutations significantly increased the insensitivity to monocrotophos. Moreover, when the Gly228Ser and Phe439Trp mutations are present together, insensitivity increased over a thousand-fold, showing that both mutations confer resistance in a synergistic manner. Presence of the mutations, however, reduced catalytic efficiency of AChE considerably, suggesting an apparent fitness cost in monocrotophosresistant mites. Reconstitution of the multiple copies of AChE having different compositions of mutations revealed that the catalytic efficiencies of the six-copy and two-copy AChEs (resembling the AD and PyriF strains of mite, respectively) were still lower but comparable to that of wildtype AChE. These finding clearly suggested that multiple rounds of Tuace duplication was needed to compensate the reduced catalytic activity of AChE caused by mutations.

Vapormate™, a new gas formulation of ethyl formate (EF) with carbon dioxide, is an alternative fumigant to methyl bromide (MB). The efficacy of the vapormate fumigation was evaluated on an acaricide susceptible and resistant Tetranychus urticae strains. A resistant strain showed resistance ratio (RR) of 21.9 and 379.6 to acrinathrin and chlorfenapyr, respectively. Fumigation was done in desiccators (6.8 L) which were empty or filled 30% in space with paprika for 6 h at 15℃ in the laboratory. The concentration adopted were 9.6, 17.2, 24.5, 36.4 mg/L in empty desiccator and 10.2, 17.9, 24.9, 35.2 mg/L in paprika-filled desiccator. In empty desiccator, susceptible and resistance T. urticae showed 100% mortality at higher concentration than 17.2 and 24.5 mg/L, respectively. In paprika-filled desiccator, susceptible and resistance T. urticae showed 100% mortality at higher concentration than 24.9 and 35.2 mg/L, respectively. Hatchability was greatly reduced by the fumigation. Hatchability was 3.7% in the empty desiccator at 9.6 mg/L and 37.2% in the paprika-filled desiccator at 10.2 mg/L.

The two-spotted spider mite, Tetranychus urticae Koch is the most harmful pest among many cropping systems, particularly vegetables and other annual crops. In this study, the methanol extract from the inner bark of Tabebuia impetiginosa was evaluated for acaricidal activity against T. urticae by using a leaf disk method and were compared with commercial acaricide, abamectin. A crude methanol extract of T. impetiginosa had strongly acaricidal activity at 2,000 ppm against the T. urticae. Methanol extract of T. impetiginosa was partitioned with hexane, chloroform, ethyl acetate, butanol and water fraction, successively. In this result, the chloroform fraction showed a strong acaricidal activity at 1,000 ppm. Therefore, active fraction of T. impetiginosa extract was purified by using silica gel column chromatography and high performance liquid chromatography. The structure of acaricidal component was analyzed by EI-MS, 1H-NMR and 13C-NMR spectra, and was identified as TI-3123. Based on the LC50 values of TI-3123 and abamectin against T. urticae were resulted in 0.011 mg/l and 0.340 mg/l, respectively. These results showed that acaricidal activity of the T. impetiginosa can be mostly attributed to TI-3123. Furthermore, TI-3123 was approximately 30.91 times more toxic than abamectin against T. urticae. All these results suggested that active component in T. impetiginosa derived materials could be use for biological control for T. urticae. Further studies should be performed to the structure activity relationship of TI-3123 and compared with its derivatives.

Spider mites are one of major pests in cultivations of various ornamental plants and also important in plant quarantine service. Due to the very small body size and high similarity within the Genus the identification of species is difficult even at the microscopic observation. To identify 5 major species (Tetranychus cinnabarinus, T. urticae, T. phaselus, T. kanzawai and T. truncatus) in the Genus Tetranychus at the molecular level, we designed 4 species-specific primer sets using nucleotide sequences of the internal transcribed spacer (ITS2) region in the nuclear ribosomal repeat unit. At the PCR diagnosis of extracted genomic DNAs of 5 species using each primer set, specific primers of both T. phaselus and T. truncates were species-specific to their own species samples. However, specific primer set of T. urticae detected T. cinnabarinus as well as T. urticae. Specific primer set of T. kanzawai detected T. truncates as well as T. kanzawai, even though detection intensities were lower in non-target species.

Due to the very small body size of spider mite, it is difficult to prepare DNA extraction simultaneously with slide samples from a single individual. Here we developed non-mashed DNA extraction method from a single spider mite to apply for molecular as well as morphological identification. Total genomic DNA was isolated from a single female adult using Genomic DNA extraction kit without the sample homogenization. DNA content of a single spider mite was 60-90 ng, which is sufficient for the PCR analysis. However, the quantity of extracted DNA and quality of the cuticle sample were dependent on the incubation time into the lysis buffer. Our results suggest that non-mashed DNA extraction method would be useful for the identification of very small mites as well as insects at the levels of DNA and morphology.

경상남도 밀양 소재 가지산도립공원에서 채집한 317개체의 거미류는 20과 59속 66종으로 동정되었다. 종지수(species richness)는 깡충거미과 12종(20.0%), 꼬마거미과 8종(12.1%), 접시거미과 5종(7.6%), 왕거미과, 코리나거미과, 수리거미과 및 게거미과가 각 4종(6.1%), 갈거미과, 비탈거미과 및 새우게거미과가 각 3종(4.5%)의 순이었다. 동물지리구에 따른 종은 범열대종 1종(1.5%), 구북구종 4종(6.1%) 및

Twospotted spider mite, Tetranychus urticae was collected from the rose greenhouse in Gimhae, Gyeongnam province in Jan, 2001. Resistant strain was reared over nine years treated with Acequinocyl (over 400 times), and increased 614 folds as compared to susceptible strain (S). Cross resistance of acequinocylresistant strain adults to eight acaricide was showed high in Cyflumetofen (108 folds) and expressed low in Abamectin (16 folds), Tebufenpyrad (7.6 folds), Fenpyroximate (6.1 folds). Against Chlorfenapyr (0.5 folds), however, showed negatively correlated cross resistance. Synergistic effects with PBO (piperonyl butoxide), an oxygenase inhibitor, DEF (S,S,S-tributyl phosphorotrithioate), an esterase inhibitor, and DEM (diethymaleate), an inhibitor of glutathion S-transferase were also investigated. Synergistic effect showed low in DEM (4.2 folds) but showed high in PBO (12 folds) and DEF (23 folds).

Field survey was conducted to determine the differences of spider community between traditional farming and environmental friendly farming at 17 localities, Korea in 2008. In guild structure, The occupancy rate of pest group, general group and natural enemy group was 37.3%, 41.0% and 21.6% respectively in environmental friendly farming, and 36.9%, 35.6% and 27.5% respectively in traditional farming. Among natural enemy group, parasitoids and predators were 15.8% and 84.2% respectively in environmental friendly farming, and 28.1% and 71.9% respectively in traditional farming. Among natural enemy group, rice field spiders were 74.4% and 62.2% in environmental friendly farming and traditional farming respectively. Among predators, rice field spiders were 86.7% in environmental friendly farming and 84.9% in traditional farming. Rice field spider community comprises 28 species of 24 genera belonging to 10 families and 30 species of 24 genera belonging to 10 families in environmental friendly farming and traditional farming respectively. Dominant families were Lycosidae, Linyphiidae and Tetragnathidae and dominant species were Pirata subpiraticus, Ummeliata insecticeps, Tetragnatha maxillosa, Gnathonarium dentatum and Packygnatha clercki in both agricultural practices. The ratio of hunting spiders and webbing spiders was similar between agricultural practices.

The molecular mechanisms and genetics of abamectin resistance mediated by target site insensitivity in the two-spotted spider mite, Tetranychus urticae, were investigated by comparing two isogenic AbaS and AbaR strains. Cloning and sequencing of full-length cDNA fragments of GABA-gated chloride channel genes revealed no polymorphisms between the two strains. However, sequence comparison of the full-length cDNA fragment of a T. urticae glutamate-gated chloride channel gene (TuGluCl) identified a G323D point mutation as being tentatively related with abamectin resistance. In individual F2 progenies obtained by backcrossing, the G323D genotype was confirmed to correlate with abamectin resistance. Bioassays using progeny from reciprocal crossings revealed that the abamectin resistance trait due to TuGluCl insensitivity is incompletely recessive.

This study was conducted to clear the regional difference in the resistance development of the spirodiclofen 36% WP, an acaricide of tetronic acid class, against two-spotted spider mite, Tetranychus urticae occurred in apple orchard since 2007. Two-spotted spider mite was collected from eight regions in the Chungnam, Chungbuk and Gyeongbuk that were major apple cultivation in Korea. An bioassay was investigated the ovicidal activity to compare with the degree of resistance development of this pest. The managed orchard in Sancheok-myeon, Myeongseo-ri, Chungju was controlled by several different acaricides from 2001 to 2008, and spirodiclofen WP was used for the last seven years. LC50 of spirodiclofen WP was estimated as 19.4 ppm in managed orchard, it showed as high as 2.6-fold (resistance ratio) comparing to those of susceptible strain showed as 7.5 ppm. LC50 of spirodiclofen WP against etoxazole-resistant two-spotted spider mite, gained from Chungbuk National University, was proved in 8.1 ppm. This observation indicates that spirodiclofen WP did not occurred in cross resistance with etoxazole SC. Other two regions in Chungju, the resistance ratio against spirodiclofen WP showed as 2.5- and 2.3-fold, respectively. In Chungnam, Gyeongbuk, it has been limited the resistance ratio under 3-fold, respectively.

The TSSM is one of the most destructive pests on various orchard trees and garden plants. Abamectin resistance mechanisms in two resistant TSSM strains (PTF, ca. 155-fold; AbaR, ca. 3700-fold) were investigated with an emphasis on target site insensitivity mechanism. Detoxification enzyme assays revealed that metabolic factors contributed by EST and/or P450are involved in abamectin resistance. Synergistic assays showed that enhanced detoxification enzyme activity is not enough to account for the high level of abamectin resistance, further suggestive of the involvement of additional resistance mechanism, most likely target site insensitivity. As a putative target site for abamectin, we cloned the cDNA fragments of glutamate-gated chloride channel (Tuglucl) and determined its full length nucleotide sequences. Amino acid sequence comparison among the four strains showed that the Gly323Asp mutation located in the third transmembrane domainis only found in the AbaR strain, suggesting it is likely associated with the target site insensitivity conferring a high level of abamectin resistance.

This study was performed to investigate the bacterial diversity isolated from the twospotted spider mite and to interpret their correlation between insect bacteria and acaricide resistance. Twospotted spider mite, Tetranychus urticae was used the resistance strains, which developed over eight years to the six acaricides such as abamectin, acequinocyl, bifenozate, etoxazole, fenpropathrin, and pyridaben, respectively. After cultivating the bacteria from body maceration, bacterial colony was selected and identified through 16S rRNA gene sequences. We are identified six genus from Pyridaben resistant strain, five genus from acequinocyl, three genus from abamectin, bifenozate, etoxazole, and two genus from fenpropathrin. However, we could not found correlation between bacterial density and diversity (phylotypes) among these resistant strains. By analyzing the diversity of population microorganisms, fenpropathrin was showed 40% of Cs value (Similarity coefficient) with susceptible strain, however, abamectin and pyridaben were perfectly different (0%) with susceptible strain. It remains to be learned about how microorganisms co-evolutionary developed with their host insect correlating to the resistance and how microorganisms play role in acaricide resistant mite.

Members of Sparassidae of Araneae are small to large sized (3-25mm) huntsman spiders (Jäger 1999). In Korea, there have been recorded 5 species, Heteropoda venatoria (Linnaeus, 1767), Micrommata virescens (Clerck, 1757), Sinopoda koreana (Paik, 1968), Sinopoda stellatops Jäger & Ono, 2002 and Thelcticopis severa (L.Koch, 1875), belonging to 3 genera (Paik, 1968, 1978, Namkung, 2002, 2003, You and Kim, 2002). In the course of survey for the spider fauna of Mt. Sobaek (1,439m elevation) located in Punggi-gun, Gyeongsangbuk-do during 2007 to 2008, one of the 16 National Parks in Korea, 2 matured females of Sinopoda forcipata (Karsch,1881) which has been known to distribute in China and Japan were collected by pitfall traps. S.forcipata is a newly recorded species for the Korean spider fauna. Female of S.forcipata was described with some natural history including vertical distribution at mountain and seasonal fluctuation, and compared distribution and habitat of 3 Korean Sinopoda species referring former reports from Korea.

The root zone applications of a systemic insecticide, carbofuran, were evaluated for their impacts on the brown planthopper, Nilaparvata lugens (Stål), and spider populations in the greenhouse and rice paddy fields. In the green house experiments, no BPH nymphs were hatched at root zone treated on 40 to 50 day-old rice, while around 20 to 54 nymphs per pot were emerged in broadcasting and foliar spray treatments. This indicates that the root zone treatment can kill the eggs of BPH effectively. This is the first study ever demonstrated the high egg mortality of BPH due to the root-zone application. In the field experiments, the density of BPH in root zone treated plots were four to six times lower than in broadcasting and foliar spray plots at the 21 days after application. The BPH outbreaks and hopper-burns were observed at all treatments except the root zone treated plot at the 28 days after application. The root-zone application did not impact on the spider population, while foliar spray killed most of all spiders just one day after application. The densities of spider in foliar spray plots were always lower than in root-zone treated and control plots. The results indicated that the root-zone application of carbofuran can control BPH effectively without adverse effects to the spiders inhabited on the paddy field.

The thermal stability and mechanical properties of Nephila clavata and Bassaniana decorata spider silks were measured and compared with those of aramid and polyester fibers. The thermal stability of the spider silk was lower than those of the commercial aramid and polyester fibers. However, the mechanical properties of the spider silk were far superior to that of the polyester fiber. The effect of the water content of the spider silk on its thermal stability and mechanical property was examined by conducting the silk to heat treatment at 100℃ under vacuum for various times. The results indicated that spider silk subjected to heat treatment for 1.5 hr had excellent thermal stability and mechanical property.

In the preceding symposium, we presented the result of the phylogenetic analysis of Stigmaeopsis spider mites (Acari: Tetranychidae) in Japan using sequence data of the Cytochrome Oxidase subunit I (COI) region of mitochondria DNA. We analyzed haplotypes representing S. longus, S. celarius, S. takahashii and S. saharai, which inhabit bamboo species of the genera Sasa and Phyllostachys (Poaceae; Bambusoideae), and two forms of S. miscanthi (HG and LW) living on Miscanthus sinensis (Poaceae; Panicoideae). Both neighborjoining and maximum-likelihood methods revealed that Stigmaeopsis consists of seven monophyletic groups, in which two forms of S. miscanthi form two distinct monophyletic groups, whereas four species of bamboo-inhabiting species comprise a polyphyletic assembly. These results imply a mismatch between diagnostic morphological characters (i.e. the length of dorsal setae) and their phylogenetic lineages for bamboo-inhabiting species, requiring re-evaluation of the use of these characters. In addition, our results indicate that plural lineages coexist in a single habitat at various regions, suggesting that differentiated lineages secondarily encounter around southwestern Japan. Interestingly, the result of phylogenetic analysis on mitochondrial COI and nuclear ITS1 region was, in part, inconsistent in internal branches. In this symposium, I re-analyzed more these data by phylogenetic network analysis. Based on the results, I make some inference about the process of habitat expansion of these mites.

Environmental tolerance of three important spider mite predators; Neoseiulus womersleyi, Neoseiulus californicus and Phytoseiulus persimilis (Phytoseiidae) was experimented by treating combination of temperature and relative humidity for egg hatching and immature survival. Egg hatching rate increased at the relative humidity incrased for three species. Temperature effects were only significant to N. californicus and P. persimilis. The lethal humidities for three species were in the range of 56-77, 82.0, 66-94% RH, respectively. Larva does not need to feed for larval development into protonymph in three tested species. No larvae survived at lower than 75% RH for N. womersleyi, but around 80% at 95% RH. N. californicus larvae survived around 50% and 100% at 75 and 95% RH. P. persimilis larve survival was decreased as the temperature increased at 75% RH, but platued around 100% at 95% RH. Cannibalism was higher in N. californicus and lower in P. persimilis. Implementation of the results was discussed relative to biological control of spider mites in open field and greenhouse crops.

The Kanzawa spider mite, Tetranychus kanzawai (Acari: Tetranychidae) constructs webs over leaf surfaces and usually lives under the webs. T. kanzawai produces two types of excreta, black and yellow pellets, and uses its webs as a place for excretion. T. kanzawai also uses its webs as a refuge when the predatory mite, Neoseiulus womersleyi (Acari: Phytoseiidae) is present. To clarify what factors deter N. womersleyi from foraging on T. kanzawai webs, I experimentally examined the effects of T. kanzawai excreta on its own fitness (fecundity) and the foraging behaviour of N. womersleyi. When the excreta of T. kanzawai was put on leaf surfaces, the fecundity of T. kanzawai adult females was reduced by the black but not the yellow faecal pellets. On the other hand, predation by N. womersleyi was reduced by the yellow but not the black pellets. Although this effect of the yellow pellets on N. womersleyi did not last on leaf surfaces, it deterred N. womersleyi from staying on the webs regardless of its freshness. These results suggest that T. kanzawai deposits black pellets on webs to avoid its negative effect on their own fitness, and yellow pellets are deposited on webs to reduce the risk of predation.