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.

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.

Why do two-spotted spider mites (Tetranychus urticae) inhabit on the underside of leaves? Why are diapause females orange? A possible key to answering these questions is ultraviolet (UV) radiation. UV radiation directly damages DNA and produces reactive oxygen species (ROS). ROS also damages DNA, dissociates proteins, and oxidizes lipids. Because mites are small, the UV/ROS-induced damage would be lethal to mites. In non-diapause females, mortalities under UV-C (250 nm) at 0.6 W m–2 and UV-B (300 nm) at 2.4 W m–2 were significantly higher than those under continuous darkness (DD; control). Oviposition rates in such treatments were significantly lower than those under DD. No significant effects for mortality and oviposition rate were observed under UV-A (350 nm) even when the intensity was as high as 2.4 W m–2. In diapause females, the differences in mortalities between all types of UV radiation and DD were not significant. Interestingly, more than half of diapause females escaped from leaf disks under all types of UV radiation, and the escape rates were significantly higher than those under DD and those for non-diapause females. This suggests that diapause females exhibit negative phototaxis. Mites inhabit the underside of leaves in summer with dense vegetation. Most of UV radiation is absorbed and reflected by leaves. Therefore, the underside of leaves is considered a suitable environment for mites to avoid UV radiation, particularly UV-B (UV-C is completely absorbed by the ozone layer). In autumn, leaves start turning yellow and red as winter approaches and finally, fall. During this phenological event, the UV-B level in the plant canopy would increases dramatically while female mites enter diapause with a change in their body color from yellow-green to orange. It is known that the orange color is mainly due to the accumulation of β-carotene, which plays a role as a scavenger of ROS. Therefore, low mortalities observed in diapause females under UV-C and UV-B may be a result of β-carotene accumulation or merely due to the increase in the escape rate. Therefore, whether the escaped diapause females are resistant to UV-C and UV-B damage needs to be confirmed. Our findings suggest that UV radiation is utilized as an effective non-chemical measure to reduce the mite population and that the selection of habitat and change in body color is the mite’s strategy to reduce the deleterious effects of UV-B.

Molecular mechanisms of monocrotophos resistance in the two-spotted spider mite (TSSM), Tetranychus urticae Koch, were investigated. The resistant (AD) strain showed ca. 3,565-fold resistance compared to a susceptible (UD) strain. No significant differences in the esterase and gluthathion-S-transferase activities were found between two strains whereas AD showed a 1.9-fold higher mixed function oxidase activity. Acetylcholinesterase (AChE) inhibition assay revealed that the AChE from AD strain is 91-fold less sensitive to monocrotophos, suggestive of the target site insensitivity mechanism. Three point mutations (G228S, A391T and F439W/Y) in the AChE gene (tssmace) appeared to primarily contribute to the reduced sensitivity of AChE as judged by the correlation study of mutation frequency versus resistance levels (LC50) of several field populations. The resulting correlation coefficients of the G228S and F439W mutations were 0.711 and 0.300, respectively, suggesting that G228S mutation may play a more significant role in resistance. The A391T mutation, saturated in all field populations examined, appears to provide a base line resistance.

Six kinds of insecticides, fenpropathrin, dicofol, milbemectin, tebufenpyrad, monocrotophos and propargite, were selected for investigating LC50s to local two spotted spider mite(TSSM) strains. The TSSMs were collected from peach (Cheongdo area) and apple orchards (Chungju, Kunwi and Sobo areas) in 2005, from strawberry plastic house (Nonsan and Damyang areas) in 2006 for experiment and some insecticides selected TSSM strains for more than 20 generations were also used. Each strain was clustered by LC50 value got from six selected insecticides treatment. Every insecticide showed about three-fourfold LC50 difference among TSSMs caught in same area. There are no specific differences in LC50 patterns of TSSM to insecticides within peach orchard and among apple orchards. But TSSMs of apple orchard and peach orchard were clustered into different group each other. Grouping of selected TSSM strains with insecticides in lab artificially showed good relationship between action mechanisms of insecticides. In strawberry strains TSSM showed regional differences between Damyan and Nonsan. The TSSMs of Nonsan showed more resistance to Tebyfenpyrad and Propargite, but TSSM of Damyang was more resistant to fenpropathrin than that of Nonsan. The TSSMs selected with monocrotophos and bifenazate, known as acetylcholinesterase inhibitors, and also pyridaben and chlorfenapyr, known as inhibitors of mitochondrial electron transportation, were grouped close respectively.

This study was conducted to investigate the regional difference in the degree of resistance development of the spirodiclofen 36% WP, an acaricide of tetronic acid class, against two-spotted spider mite, Tetranychus urticae occurred in apple orchard. Two-spotted spider mite was collected from every three regions in the Chungbuk and Gyeongbuk. To compare with the degree of resistance development, this pest was focused on the ovicidal activity (when treated acaricide). The managed orchard in Sancheok-myeon, Myeongseo-ri, Chungju was controlled by several different acaricides from 2001 to 2007, and spirodiclofen WP was used for the last six years. In case of managed orchard, LC50 of spirodiclofen WP was 14.0 ppm, it showed 1.6 fold (resistance ratio) that was estimated as considerably low level resistance ratio comparing to the those of susceptible strain showed in 8.7 ppm. LC50 of spirodiclofen WP against etoxazole-resistant two-spotted spider mite, gained from Chungbuk National University, was investigated in 7.5 ppm. This observation indicates that spirodiclofen WP did not occurred in cross resistance with etoxazole SC. At other regions in Chungju, the resistance ratio against spirodiclofen WP showed as 1.0 and 1.4 fold, respectively. In Gyeongbuk, one region of Yecheon and two regions of Yeongju, it showed as 0.7, 0.8 and 0.9 fold, respectively.

장미의 병해충 방제에 등록되어 있는 34종, 등록되어 있지 않은 5종, 그리고 보조제 3종, 충 42종의 농약에 대한 칠레이리응애(알, 약충, 성충)와 점박이응애(알, 성충)의 선택독성과 칠레이리 응애에 의한 점박이응애 밀도억제효과를 조사하였다. 살비제 중 acequinocyl, bifenazate, fenbutatin oxide, spirodiclofen은 칠레이리응애에 대해서 독성이 낮았으나, 점박이응애에 대해서는 독성이 높았다. 살충제는 acetamiprid, imidacloprid, spinosad, thiamethoxam, acetamiprid＋etofenprox가 칠레이리응애와 점박이응애에 대해서 독성이 없거나 적었다. 살균제 중에는 azoxystrobin, kresoximmethyl, myclobutanil, nuarimol, triadimefon, triflumizole, oxadixyl＋mancozeb이 칠레이리응애와 점박이응애에 대해서 영향이 없었다. 농약보조제인 cover와 siloxane은 칠레이리응애에 대해서 독성이 컸으나, spreader는 영향이 없었고, 점박이응애에 대해서는 독성이 없거나 낮았다. 장미시설하우스에 서 칠레이리응애에 의한 점박이응애 밀도억제효과를 조사하기 위하여, 점박이응애의 밀도가 잎당 65.3마리였을 때, 칠레이리응애를 주당 30마리 방사하였다. 방사 후 11일에 점박이응애 밀도가 잎당 3.8마리로 크게 감소하였고, 방사 후 20일에는 잎당 0마리로 밀도억제효과가 높게 나타났다. 조사기간 동안 흰가루병 방제로 살균제 4회(kresoxim-methyl, myclobutanil, nuarimol, triflumizole)와 총채벌레 방제약제를 1회(spinosad)처리하였으나, 칠레이리응애 밀도에는 영향이 없었다. 이상의 결과로 보아 장미 병해충의 종합관리체계에서 칠레이리응애에 독성이 적은 약제와 칠레이리응애를 함께 이용할 수 있을 것이다. controllability. Based upon these results, it is recommended that the developing nursing interventions to change causal attribution and self-efficacy is necessary. A number of theoretical relationships and empirical finding are confirmed by this data, and future proposals in research is suggested. 따라서 교사들의 관심유형과 실행수준에 따라 수행평가에 대한 지원을 달리함으로써 교사들의 관심도와 실행수준을 향상시켜야 할 것이며 보다 효과적인 수행평가가 실시되도록 해야 할 것이다.. 결론적으로 현재 우리나라에서는 갈색 정도의 차이 문제이지 갈색란을 좋아함을 알 수 있었고, 교육에 의해 조금씩은 고정 관념을 바꿀 수 있는 가능성을 확인할 수 있었다.ique impact at 0.70 km/s and 0.91 km/s were compared with experimental results and Eulerian hydrocode CTH simulation results. The Lagrangian code NET3D is superior to Eulerian code CTH in the computational accuracy. Agreement with the experimentally obtained final deformed cross-sections of the projectile is excellent. (3) Agreement with the experimental ballistic limit data, particularly at the high-obliquity impacts, is reasonably good. (4) The simulation result

점박이응애(Tetranychus urticae)에 대한 34종 terpene의 훈증독성, 접촉독성 및 기피효과를 조사하였다. 훈증독성은 10/1(공기)의 농도에서 isosafrole, safrole이 모두 98.4%의 살비율을 나타내었다. 이 두 화합물의 LD값은 각각 2.6, 4.3/1이었다. 접촉독은 isosafrole만이 알에 대해서 60.2%의 살란활성을 보인 것 외에 대부분의 terpene에서 활성이 낮거나 없었다. 약제감수성 계통에 대한 기피반응을 조사한 결과 hexanoic acid와 limonene이 1,000ppm에서 각각 79.1%와 87.8%의 기피효과를 나타내었다. 한편 fenprothion저항성 계통과 pyridaben저항성계통에 대해서 hexanoic acid는 각각 77.8%과 83.3%의 기피효과를 나타내었다. 그러나 두저항성계통에 대한 limonene(1,000ppm)의 기피효과는 각각 17.8%와 10.0%로서 감수성계통에 대한 기피효과와 상반된 결과를 나타내었다.다.

Tetradifon에 저항성인 점박이응애(Tetranychus urticae) 계통을 얻기 위하여, 1995년 3월 경북 안동의 농가 사과원에서 채집한 월동성충을 실험실에서 Tetradifon으로 4개월 동안 누대 도태시켰다. 5회 도태시킨 계통(Td5계통, 저항성배수 371.8배)으로써 Tetradifon 저항성의 유전양식과 8종의 살란성 살비제에 대한 교차 저항성 정도를 生妹殘留法(wholeplant residual method)으로 검정하였다. 난(RS 교배, Td5femaleSmale, 또는 SR 교배, SfemaleTd5male)의 log농도-미부화율 선이 S계통 보다는 Td5계통에 치우쳐 있어 점박이 응애 난의 Tetradifon에 대한 저항성은 우성으로 유전된다고 할 수 있으며, 저항성의 우성도는 RS난이 0.998이고, SR난이 0.262이어서 이 저항성의 유전에는 세포질적인 요소 또는 어미의 영향이 있는 것으로 생각된다. 즉 RS 교배의 경우에는 완전우성으로, SR 교배의 경우에는 불완전우성으로 유전되는 것 같다. Td5 계통은 clofentezine . benzoximate . chlorfenson에 대해서 교차 저항성을 나타내었고, fenazaquin . pyridaben . flufenoxuron . tebufenpyrad . fenothiocarb 등에 대해서는 비교차저항성을 나타내었다.

전국 6개 지역의 사과원에서 점박이응애를 채집하여, 15종의 살비제에 대한 성충과 알의 감수성을 비교하였다. 공시살비제에 대한 성충과 알의 약제감수성은 서로 비슷한 경향을 나타내었다. 약제의 종류별 감수성은 지역에 따라 다향하게 나타났는데, 지역 계통별 살비제에 대한 저항성비가 20이상인 약제들을 성충과 알로 나누어 정리하며, 성충의 경우, 수원 계통은 azocyclotin, cyhexatin, fenbutatin-oxide에 대하여, 대전 계통은 dicofol, fenbutatin-oxide에 대하여, 청주 계통은 dicofol에 대하여, 진주 계통은 cyhexatin, dicofol, fenbutatin-oxide에 대하여 높은 저항성을 나타내었다. 알의 경우는 수원 계통은 bifenthrin, clofentezine, hexythiazox, tetradifon에 대하여, 군위, 청주, 광주 계통들은 bifenthrin에 대하여, 대전 계통은 amitraz, bifenthrin에 대하여, 진주 계통은 amitraz, bifenthrin, clofentezine, dicofol, tetradifon에 대하여 높은 저항성을 나타내었다. 그러나, abamectin, chlorfenson, fenpyroximate에 대한 약제감수성은 채집 지역에 관계없이 실내 감수성 계통과 차이가 없었다.

아프리카 나이제르산 13관 21종 식물체의 부위별로 채집된 31 시료 메탄올 추출물의 벼멸구에 대한 살충활성 및 점박이이응애에 대한 살비활성을를 가각 미량국소처리법과 잎침지법으로 조사한 결고, 시료의 부위 및 종에 따라 살충 및 살비활성에 커다란 차이를 보였다. Caesalpinacras과의 Cassia occidentalis와 Cassia tora 전부위 및 Mimosaceas 과의 Prosopis chinensts줄기의 메탄올 추출물은 벼멸구에 대해서 강한 살충활성을 보인 반면, 비름과의 Celosia trigyna 전부위, Combretaceae과의 Combretum glutinotum 잎과 Combretum micronthum 전부위 및 Prosopis chinensis 잎과 열매의 메탄올 추출물은 점박이응애에 대해 강한 살비활성을 나타내었다

점박이응애(Tetranychus urticae Koch)의 감수성계통(S)과 dicofol 저항성계통(R)을 공시하여 dicofol저항성의 안정성을 조사하였다. Dicofol 저항성계통(저항성비 23.0)의 약제도태없는 조건하에서 사육된 암컷성충의 dicofol에 대한 저항성 수준은 1년이 경과된 후에도 변화가 없었다. 그러나 1년 이후부터는 감소하기 시작하여 2년째에는 저항성비가 15.8배, 3년째에는 10.7배로 감수성쪽으로 기울었다. 점박이응애의 dicofol 저항성계통과 감수서계통의 상호교배 에서 얻어진 세대별 약제 감수성도 세대가 경과됨에 따라 감수성쪽으로 기울었다.