VapormateTM, the new gas formation of ethyl formate(EF) with carbon dioxide, is an MB(methyl bromide) alternative fumigant for grains and perishable commodities especially to control quarantine pest. To gain systematic efficacies of VapormateTM, vaporized gases in Tedlar bag were collected from liquefied gases in cylinder. Vaporized gases were used for collecting efficacy data to Tetranychus urticae, two-spotted spider mite, for 6hr at 26± 1℃. When applied 25, 51, 77 and 102 ml/L of vaporized gas for 6hr, mortality of T. urticae female adult were 83.3, 97.8, 100, and 100%, respectively, at 24hr after fumigation. Also, at 77 and 102 ml/L of vaporized gas for 4hr treatment at 26± 1℃, the mortality of T. urticae female was 96.7 and 97.8%, respectively. This preliminary result may help to understand further scaled-up VapormateTM fumigation applied with different type of commodities.

Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseidae) is well known as an effective natural enemy of two-spotted spider mite, Tetrnychus urticae Koch (Acari: Tetranychidae). However, successful biological control usually requires adequate management of temperature. While P. persimilis did suppress T. urticae at moderate condition (20~25oC) in a week or so, the density of P. persimilis was barely increased at cold condition (5~10oC) in three weeks or so. The problem is that winter temperature is too cold for the development and reproduction of P. persimilis in greenhouse for forcing strawberry. Night temperatures in greenhouse were even mostly lower than 6oC. So, winter application of P. persimilis against T. urticae is useless. To avoid damage from T. urticae in early spring season, it was better that the release amount of P. persimilis was double at middle- and late-October, instead of early-November to next early-February. If necessary, the double releasing of P. persimilis might be good for control of T. urticae at middle- and late-February.

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 improve the effect of environment-friendly Tetranychus urticae pesticide through the development of Tetranychus urticae biopesticide using the plant extract. Tested extracts were fig leaf extract, viburnum erosum extract; besides Sophora flavescens Ait extract, Derris root extract, Tobacco leaf extract, and they were proved to be the caricidal effect of two spotted spider mite adults by spraying on the French bean leaf inoculated for Tetranychus urticae with each concentration; 500ppm, 200ppm, 100ppm, 50ppm. In the control treatments, caricidal effect was compared with only ‘Eungsami’ (500ppm, 200ppm, 100ppm, 50ppm), of which the main ingredient as environment-friendly organic material is, and distilled water. The caricidal effect of tested extracts to the two spotted spider mite adult was the highest in the Sophora flavescens Ait extract and Tobacco leaf extract over 90%, and comparatively low in the Derris root extract. When the caricidal effect of ‘Eungsami’ was compared with two spotted spider mite adults with each concentration, ‘Eungsami’(500ppm) and Tobacco leaf extract(500ppm) were very excellent as each 95.5%, 98.7% in treated concentration. The effect of Sophora flavescens Ait extract was also high as 96.5%. In the low concentration(50ppm), Sophora flavescens Ait extract was 45.8%, Tobacco leaf extract was the most effective as 53.8%.

This study was conducted to develop an organic control method of two spotted spider mite (Tetranychus urticae) by using cooking oil and yolk mixture (COY) through evaluating its acaricidal activity in laboratory and green house. In laboratory, there is no significant difference in acaricidal activity against T. urticae within the COY including soybean, canola (rape seed), sunflower and olive oil. The acaricidal activity against T. urticae. increased from 17.6% to 94.1% as the COY became concentrated between 0.1% to 1%. The COY acricidal activity was effected by the quantity of treatment according to application methods. The COY dealt with T. urticae eggs presented 95% of the ovicidal activity. In rose greenhouse damaged by T. urticae, the COY (0.3%) was sprayed three times and resulted in the high control value of mites between 69.0% to 89.6%.

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with nitrogen contents of 5 mM, 10 mM, 30 mM, and 60 mM. As the nitrogen level in hydroponics increased, it also increased in the plant whereas that of K, Ca, and Mg decreased. More nitrogen in hydroponics resulted in increased contents of water and crude protein, and decreased ash, carbohydrates, and fibers within the plant. Biomass was the heaviest as 989.5 g at 10 mM and the lightest at 60 mM. Leaf thickness and the content of chlorophyll increased as the content of nitrogen increased. Laboratory leaf disc tests obtained from plants grown at various nitrogen levels revealed that feeding and oviposition preferences of T. urticae were high at 30 mM and low at 5 mM. Ratio of damaged leaf by naturally occurring T. urticae on eggplants of 99 days post-transplant in the greenhouse was the highest as 98% at 60 mM. Degrees of damage on eggplants with and without T. urticae infestation turned up more as the differences in the levels of nitrogen in the hydroponics get bigger. No definite differences in the rate of T. urticae development was found between nitrogen treatment levels but, mortalities in immature stages dropped as the nitrogen levels went up. Adult longevity was the longest of 11.9 for female and 6.9 days for male at 60 mM. Oviposition period was also the longest as 11.7 days at 60 mM and shortened as the level of nitrogen decreased. The number of eggs oviposited was the most as 144.4 at 60 mM while it was the least as 41.0 at 5 mM. Sex ratio was 0.75 in favor of female at 10 mM. R<SUB>o</SUB> and T increased, no trends were detected in r<SUB>m</SUB> and , while Dt decreased as the levels of nitrogen went up.

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with silica contents of 0 mM, 1.7 mM, and 5.1 mM. As the levels of silica increased, those of N, P, K, Ca, and Mg decreased and those of Si increased. While contents of calory, crude protein, carbohydrates, and vitamin C decreased, those of ash, fiber, and sugar increased. Biomass and content of cholorophyll decreased as the level of silica increased while leaves became thicker. Laboratory leaf disc tests provided with various silica levels revealed that feeding preference of T. urticae was the highest at 0 mM and the lowest at 1.7 mM. The oviposition preference decreased as the levels of silica increased, on the lower leaf appeared to hinder the feeding and the oviposition of T. urticae. The development slowed down both in female and male. Adult life span of female shortend as the silica level increased and that of male was the longest as 5.7 days at 0mM and the shortest at 1.7 mM. Oviposition period also shortened as the silica content increased. The number of eggs laid was the most as 86.3 at 1.7 mM while average oviposition per day was the least as 7.7 at 0 mM. No differences in hatchability was detected whereas the ratio of sex was the highest as 0.71 in favor of female at 0mM. R<SUB>o</SUB> and T decreased as the levels of silica increased. Rm and was the lowest at 5.1 mM while Dt was the longest as λ 1.8271 at 5.1 mM and the shortest as 1.6991 days at 1.7 mM. Silica content in eggplant turned to affect the development of T. urticae, however, it deterred T. urticae from feeding and oviposition and the rate of increase tended to decrease due to lesser nutrients in the eggplant leaf.

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with potash contents of 0 mM, 2 mM, 6 mM, and 12 mM. As the levels of potash increased, that of nitrogen decreased and that of P, K, Mg increased in the plant. While contents of crude protein and fiber decreased, those of ash and sugar increased. Carbohydrate content was the highest at 2 mM. Water contents increased as those of potash increased with the exception at 0 mM. Biomass was the heaviest as 552.7 g at 6 mM and the lightest at 0 mM. Leaf thickness and the content of chlorophyll increased as the content of potash increased. Laboratory leaf disc tests provided with various potash levels revealed that feeding and oviposition preferences of T. urticae were high at 6 mM and 12 mM, respectively. Ratio of damaged leaf by naturally occurring T. urticae on eggplants of 99 days post-transplant in the greenhouse was the highest at 6 mM. Development of immature stages of T. urticae shortened as the levels of potash increased with a less tendancy in male than in female. No differences were detected in adult longevity and oviposition period but the number of eggs laid was the most as 84.7 at 6 mM and the least as 40.6 at 0 mM. There were no differences in the rate of egg hatch and the ratio of sex. R<SUB>o</SUB>, r<SUB>m</SUB>, and were the highest at 6 mM and the lowest at 0 mM. T and Dt were the λ lowest at 6 mM and the highest at 0 mM. There was a descending trand of T. urticae developmet when levels of potash either gets high or low in the hydroponics.

Temperature dependent development of Tetranychus. urticae Koch was studied on the leaf of eggplant at 17, 22, 27, 32 and 37℃, T. urticae showed a minimum mortality at 27℃ and it increased at higher or lower temperatures than 27℃. The hatchability was low at 17 and 37℃. The duration of development decreased with increasing temperatures i.e., 5.3d at 37℃ and 25.8d at 17℃. Linear regression analysis of temperature vs. rate of development yielded the higher r² ≥ 0.88 resulting in a good fit of the estimated line in the range of 17~37℃. Developmental zero temperature was 12.5℃ for the entire immature stage of female and 12.8℃ for that of male. Thermal constants were 80.5 and 74.7 degree days for those of female and male, respectively. Adult life span and oviposition period decreased with increasing temperatures. The number of eggs laid per female peaked at 141.0 eggs at 27℃, while that was a minimum 78.0 eggs at 37℃. Rate of hatchability, ratio of female, and R₀ were increased up to 27℃, and than declined thereafter. Intrinsic rate of natural increase (Rm) increased with rising temperatures and showed a maximum 0.5652 at 37℃. Also, λ increased with increasing temperature. Doubling time (Dt) and generation time (T) decreased with increasing temperature.

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.

As suggested by Kawashima (2006), the most abundant Tetranychidae was Tetranychus sp. as a pest in persimmon orchards. The observatory orchards were selected 16 in total, 2 from Gurye, 2 from Gwangyang, and 2 from Suncheon in Jeonnam Province and 3 from Jinju, 4 from Sacheon, and 3 from Sancheong in Gyeongnam Province. Number of mites in 100 persimmon leaves were observed from each orchards nearly every ten days. Careful rearing of the mites sample collected from the four observaory persimmon fields at which the mite had occurred the most seriously among 16 fields and results from taxanomical identification process indicated that the species was identified Tetranychus urticae. Maximum number of T. urticae reached to 436 on 27 June at Jeongdong, Sacheon, 108 on 1 August at Sinann, Sancheong, 406 on 26 June Okgok, Gwangyang, and 509 on 15 June Muncheok, Gurye. When the number reached to more than 400 mites, the persimmon leaves changed from clear yellow dots, to pale yellow, and to grey in the backside. An experiment was conducted to control T. urticae and to select highly active miticide in persimmon orchards in Jinju and Sacheon. Spiromesifen 20SC and acequinosyl 15 SC were effective.

The study was conducted to investigate dispersal of T.urticae and its predatory mite on connected strawberry leaves. The experiments were run on laboratory conditions, 24±1℃, 50-65% RH, and a photoperiod of 16:8 (L:D). The excised leaf disk (diameter 3cm) of two strawberry varieties- Maehyang, Seolhyang- were placed upside down on a water-saturated cotton pad in an aluminum pan (width x length 17.4 x 21.5cm). Twenty leaf disks were placed on each experimental set and the disks (width x length 4 x 5 ca) were connected with each other for dispersing of T. urticae and its predatory mite. There were six different experiment sets - two strawberry varieties and three treatments (no predatory mite, releasing Neoseiulus californicus, and releasing Phytoseiulus persimilis). The experiment sets were covered with plastic cage to protect from invading other insects and mites. The investigation was conducted by examining two or three times per week and all life stages of T. urticae and predatory mite were reported until all leaves were occupied by mites. Repeated-measures data were analyzed by MANOVA. The average number of T.urticae per cm2 was no significant difference between two strawberry varieties in no predatory mite system (F=0.65, p>0.4195). Although the external structure of two strawberry varieties is very similar the dispersal rate of T. urticae was different between two strawberry varieties in all experiment sets. However, the number of T. urticae per cm2 was no significant different (df=1, F=1.28, p>0.2628). Within the same strawberry variety T.urticae populations among experiment sets were significant different (df=2, F=14.95, p<0.0001 Seolhyang, df=2, F=15.03, p<0.0001 Maehyang).

Insecticidal activity of 20 plant species against adults of Myzus persicae, female adults of Tetranychus urticae, and 2<SUP>nd</SUP> or 3<SUP>rd</SUP> instar larvae of Plutella xylostella was evaluated in this study. Thirteen plant extracts showed over 80% acaricidal activity to T. urticae at the concentration of 1%, while Capsicum annuum (hot-pepper seed), Inula helenium, and Acorus calamus revealed 82.8-86.2% acaricidal activities at 0.5%. Insecticidal activities of the plant extracts to M. persicae and P. xylostella were relatively low compare to the mite. Among the plant extracts, C. anuum and Brassica juncea revealed 48.6% and 42.9% respectively insecticidal activities to the aphid at the concentration of 0.5%. Extracts of C. anuum and Jeffersonia dubia provided 55% and 50% insecticidal activity against P. xylostella at 1%. And, the highest antifeeding activity of the insect was observed in the J. dubia extract as 79.4%. Results indicated that some plant extracts including hot pepper seed could be used as potential botanical pesticides for organic farming.

Biological control of Tetranychus urticae by Phytoseiulus persimilis was observed in eggplant greenhouse for spring and autumn season culture. Tetranychus urticae was controlled to low density of less than 1 mite from June 24 after P. persimilis were released 3 times at rate of 10 per plant on June 1, 11, and 18, 2004 in spring season experiment. The population of Tetranychus urticae was also less than 1 mite per eggplant leaf from September 1 to October 22 after three times releases of 10 P. persimilis in autumn season experiment. In Phytoseiulus persimilis released plot, the percentage of leaves with T. urticae adults and nymphs were 8.6~13.3% and 5% or less in spring and autumn season experiment. The density of T. urticae was from 1 to 2 on leaves with T. urticae adults and nymphs.

점박이응애(Tetranychus urticae)에 대한 3종 식물정유(caraway oil, hyssop oil, lime oil)의 기피활성을 조사하였다. 이들 중 caraway oil이 1,000 ppm의 농도에서 의 기피효과를 나타내었으며, GC와 GC-MS로 분석한 결과 carvone과 limonene이 주요한 성분이었다. 따라서 caraway oil의 주요한 화합물에 대한 기피활성을 검정결과 limonene의 1,000과 100 ppm에서 각각 와 의 기피효과를 나타내었다.

2000년 12월 경북 칠곡의 장미재배지에서 채집한 점박이응애를 실험실에서 4년 동안 bifenizate로 150회 이상 도태하여 248.8배의 저항성계통을 얻었다. 이 저항성 계통의 유전과 9종 살비제에 대한 성충과 알의 교차저항성 유무를 조사하였다. 감수성계통 수컷과 저항성계통 암컷을 상호교배하여 얻은 우성도는 성충과 알에 대해서 각각 0.48, 0.94로 불완전우성이었으며, 으로 상호 교배하여 얻은 우성도는 성충과 알에 대해서 각각 -0.85, -0.17로 불완전열성이었다. 이 저항성 점박이응애의 성충은 acequinocyl, fenpyroximate에 대해 각각 9.9, 5.0배의 교차저항성을 나타내었으며, emamectin benzoate, milbemectin에 대해서는 각각 0.14, 0.04배의 역상관교차저항성을 나타내었다. 알은 amitraz, emamectin benzoate, fenpyroximate, milbemectin, pyridaben, spirodiclofen에 대해 각각 22.0, 11.7, 32.3, 16.3, 394.8, 19.5배의 교차저항성을 나타내었으며, abamectin에 대해서는 0.01배의 역상관교차저항성을 나타내었다.

수원시 이목동에 있는 원예연구소의 사과원에서 조사한 1958년부터 1998년까지 자료를 바탕으로 사과응애와 점박이응애의 역사적 발생변동 과정을 추적하였다. 1970년까지는 사과응애가 우점하였고 1980년 이후에는 점박이응애로 우점종이 바뀌었으며, 그 변화는 1970년 중반을 전후로 나타났다. 이러한 변화를 설명하기 위하여 3가지 가정, 즉 첫째, 두 종의 경쟁에서 점박이응애가 승리한다. 둘째, 과원의 초생은 점박이응애의 수상이동 여부를 결정하는 중요한 요소이다, 즉 초생이 파괴되었을 때 점박이응애의 수상이동이 촉진된다. 셋째, 과원생태계가 교란되지 않을 때 응애류는 천적에 의하여 개체군 밀도가 조절된다 하에 약제살포(고독성 비선택적 약제 처리 및 선택적 저독성 약제처리)와 초생관리(초생재배 및 청경재배=제초제 살포)에 따른 두 종의 장기적 상호작용 결과를 추정하였다. 고독성 농약/초생재배 시스템에서는 점박이응애의 수상이동이 제한되어 사과응애는 경쟁을 피할 수 있고, 또한 천적상이 파괴되기 때문에 전 생육기간 동안 사과응애가 우점한다. 고독성 농약/청경재배 시스템에서는 계절초기부터 점박이응애가 수상으로 이동하여 사과응애를 경쟁적으로 배제시킴으로써 점박이응애가 우점한다. 저독성 농약/초생재배 시스템에서는 점박이응애의 수상이동이 제한되어 사과응애가 우점하지만 천적의 작용으로 높은 밀도를 형성하지 못한다. 저독성 농약/청경재배 시스템에서는 점박이응애가 수상으로 이동하여 사과응애와 경쟁하지만 천적의 작용으로 밀도가 낮아져서 경쟁압력이 낮아지므로 생육후기 사과응애의 발생이 가능하다. 따라서 계절초기 사과응애, 계절후기 점박이응애가 우점하는 형태로 공존할 수 있다. 본 자료에서 제시한 점박이응애 우점화 현상은 부분적으로 고독성 농약/청경재배 시스템 상태에서 두 종의 장기적 상호작용의 결과로 설명될 수 있었다. CAD를 이용하여 살펴보고자 한 것이다. 연구방법으로는 가장 일반적인 실로 묶기, 전통적인 손바느질 느낌이 나는 시침질, 현대적 느낌이 강한 깡통에 의한 묶기와 기하학적 효과가 나는 접기 등의 홀치기염색 기법으로 수작업 한 다음 CAD를 이용하였다 연구의 결과는 다음과 같다. 첫째, 홀치기염색기법에 의해 제작된 패턴을 모티브로 하여 수작업에서 얻지 못하는 다색사용가능성이 주�