Fumigation of fruits and vegetables during quarantine and pre-shipment (QPS) treatment should be effective with a shorter fumigation time to minimize phytotoxicity. In this research study, a shorter fumigation time, 2 hours exposure which is shorter than that of the current commercial fumigation procedures using a lower dose of ethyl formate (EF) mixed with phosphine (PH3) on strawberry was investigated. The reciprocal effect between EF and PH3 against nymphs and adult Myzus persicae (Sulzer) and Tetranychus urticae (Koch) was evaluated. In addition, L(Ct)50 and L(Ct)99 of EF only and EF mixed with PH3 were analyzed at 5°C and 20°C. The synergistic ratio (SR) of L(Ct)50 and L(Ct)99 for the nymph and adult stages of M. persicae were >1.0, which indicated a synergistic effect between EF and PH3. However, the SR values of L(Ct)50 and L(Ct)99 of the nymph and adult stages of T. urticae were ≤1.0 indicating that there was no synergistic effect between the two fumigants against T. urticae. Our results showed that the reciprocal effect between EF and PH3 has different effects on M. persicae and T. urticae. This could be attributed to the biological and physical differences between the class Arachnida and Insecta. The synergistic effect between EF and PH3 against M. persicae within a shorter exposure period and without phytotoxicity on fruits and vegetables will significantly benefit the horticultural industry.

점박이응애는 광식성 초식자로서, 사과의 주요 해충 중 하나이다. 사과 품종에 따라 점박이응애의 밀도 형성이나 피해 규모가 다르게 나타난다. 세 가지 품종, 쓰가루, 홍로, 후지의 잎에 대한 점박이응애의 이동 선호성, 발육속도, 그리고 산란능력이 다른지를 시험하였다. 잎 절편을 이용한 실험 결과, 이동 선호성은 쓰가루나 홍로보다 후지 잎에서 높았다. 알에서 성충까지 발육기간은 후지 잎에서 가장 짧았고 홍로에서 가장 길었다. 암컷 성충 수명은 후지에서 가장 짧았다. 암컷의 총산란수는 사과 품종에 따라 다르지 않았지만, 일 평균 산란수는 후지에서 높았다. 생명표 분석 결과 홍로 잎에서 점박이응애의 적합도가 가장 낮게 나타났다. 이상의 결과는 사과원에서 품종에 따른 점박이응애 발생 양상의 차이를 설명 해주고 있으며, 향후 다양한 사과 품종에 대한 평가를 통해, 품종별 응애류 관리 전략 개발에 기초 자료가 될 것이다.

본 실험은 삼채에 발생하는 점박이응애의 효율적인 약제방제전략의 기초 자료를 확보하고자 시판되고 있는 10종의 살비제에 대해 약제감 수성과 포장 방제효과를 평가하였다. 점박이응애 암컷 성충에 대한 실내감수성 평가 결과 Abamectin EC, Pyflubumide SC, Cyenopyrafen SC, Acequinocyl SC가 100%의 살비효과를 나타내었고, Pyflubumide SC, Acequinocyl SC, Etoxazole SC는 부화율이 0%로 나타나 100% 의 살란효과를 나타내었다. 실내감수성 평가에서 살비효과가 우수했던 Abamectin EC, Pyflubumide SC, Cyenopyrafen SC, Cyflumetofen SC, Acequinocyl SC를 대상으로 포장검정을 평가한 결과, 약제처리 7일차에서 모든 처리구는 90.3% 이상의 방제가를 나타내었다.

해충의 예찰 없이 작물 정식 초기에 천적을 먼저 적용할 수 있는 천적-서식처 혼합적용(Natural Enemy in First; NEF)기법의 방제효과를 확인하였다. 시설 딸기에서 조사 12주차에 NEF처리구와 천적 단독 처리구에서 친환경자재 처리구 대비 각 83%, 70%의 점박이응애 밀도 억제효과를 확인할 수 있었다. 또한 예찰 없이 작물 정식 초기에 NEF를 적용한 처리구에서 천적 단독 처리구보다 3배 이상의 높은 천적 밀도를 확인하였다.

This study was conducted aiming to figure out two things. First, knowledge of the change in spatial distribution of Tetranychus urticae depending on how to control it (using pesticide or natural enemy). Second, spatial association of T. urticae and Phytoseiulus persimilis in biocontrol plot (B.P). The data was analyzed by spatial analysis by distance indices (SADIE) using global aggregation index, Ia . Ia values were 0.77-1.37 in conventional plot (C.P) and 0.88-1.68 in B.P, respectively. However, the fluctuation level of Ia in B.P was higher than C.P. Therefore, the results indicated that there was a clear spatial pattern change in B.P, i.e. prey’s spatial distribution is affected by natural enemy. And spatial association analysis showed that T. urticae and P. persimilis have positively associated. It means that T. urticae is relatively low mobile prey, and P. persimilis is relatively high mobile predator.

Carbonyl sulfide(COS) is a naturally generated gas from fermentation process of microbes and from plant root and stem. COS was firstly registered as a fumigant at 1993 to control stored product pests. To supplement environmental problems and toxicity of commercial fumigants and develop new fumigant, we have processed the susceptibility assessment of carbonyl sulfide on important agricultural pests, Myzus persicae and Tetranychus urticae. Every growth stages of two insect species were tested, and five dosages of carbonyl sulfide were treated for 4 hours, and the mortality was investigated after 24 hours of treatment. Nymphal stage of M. persicae was completely controlled at more than 20 mg/L dosage, and adult stage showed 95.8% mortality at 80 mg/L dosage. The LC50 of M. persicae was 7.314mg/L for nymph and 26.117mg/L for adult stage. Egg stage of T. urticae showed 91.2% mortality when treated with 100mg/L carbonyl sulfide, and nymph and adult stage showed 100% and 94.1% mortality at 8mg/L and 80mg/L, respectively. The LC50 of T. urticae was 73.110mg/L for egg, 2.818mg/L for nymph and 12.054mg/L for adult stage.

Miticidal and repellent activity of twenty plant essential oils against the adults of two spotted spider mites, Tetranychus urticae, were examined. Sandalwood oil was the most potent one in mortality, whereas clary sage oil exhibited the greatest repellent activity. On those twenty essential oils tested, no apparent correlation between toxicity and repellency was observed. The chemical compositions of sandalwood and clary sage oils were identified via GC/MS analyses. The major constituents of sandalwood oils were sesquiterpene compounds, whereas the major ones for clary sage oil were monoterpenes. Among the major components in clary sage oil, linalyl acetate was not only the most abundant constituent, but also the most responsible one for its repellent activity against the adults of the two spotted spider mites. Nevertheless, the combination of seven major constituents of clary sage oil showed lesser repellent activity than the original essential oil did, implying the presence of interactions between the major and minor constituents affecting the overall repellent activity of the crude oil.

본 연구에서는, 20종의 식물정유를 이용하여 점박이응애 성충에 대한 살비활성 및 기피활성을 확인하였다. 살비활성 평가에서는 샌달우드 오일이, 기피활성 평가에서는 클라리 세이지 오일이 가장 높은 효과를 나타내었고, 평가에 사용한 20종의 식물정유간에는 살비활성과 기피활성간 의 상관관계가 매우 낮게 나타났다. 높은 활성을 나타낸 정유들의 혼합시험에서는, 거의 대부분의 조합이 서로간에 저해효과를 갖는 것으로 확인되었다. 샌달우드 및 클라리 세이지 오일의 구성성분은 GC/MS 분석을 통해 확인하였으며, 샌달우드는 세스퀴터펜류가, 클라리 세이지 오일은 모노 터펜류가 주종을 이루었다. 클라리세이지 오일의 구성성분 중에서는 linalyl acetate가 가장 높은 함량을 갖고 있을 뿐만 아니라, 해당정유가 기피효과를 갖는 주된 효능물질임을 확인하였다.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pest species devastating many horticultural and ornamental crops and fruit trees. In the present study, a field strain was collected in January 2001 and has been selected for sixteen years with acequinocyl. The resistance ratio calculated from the LC50 of eggs and adults was 191- and 4,237-fold, respectively. The laboratory-selected acequinocyl resistance (LSAR16) strain was screened with 11 acaricides for cross-resistance. The detoxifying enzyme activities and quantitative real-time PCR analysis were performed in the LSAR16 strain. Crossing experiments revealed that LSAR16 strain was inherited maternally, incompletely dominant and monogenic. Most importantly, we identified two new point-mutations at mitochondrial cytb from acequinocyl resistant T. urticae.

A fixed-precision-level sampling plan was developed to establish control of the two-spotted spider mite, Tetranychus urticae, in two strawberry greenhouses (conventional plot, natural enemy plot). T. urticae was sampled by taking a three-leaflet leaf (1 stalk) from each plant (3 three-leaflet leaves) from each sampling position. Each leaflet was divided into three different units (1-leaflet, 2-leaflet, and 3-leaflet units) to compare relative net precision (RNP) values for selection of the appropriate sampling unit. The relative net precision values indicated that a 1-leaflet unit was more precise and cost-efficient than other units. The spatial distribution analysis was performed using Taylor’s power law (TPL). Homogeneity of the TPL parameters in each greenhouse was evaluated by using the analysis of covariance (ANCOVA). A fixed-precision-level sequential sampling plan was developed using the parameters of TPL generated from the combined data of the conventional plot and natural enemy plot in a 1-leaflet sampling unit. Sequential classification sampling plans were also developed using the action threshold of 3 and 10 mites for pooled data. Using the results obtained in the independent data, simulated validation of the developed sampling plan by Resampling validation for sampling plan (RVSP) indicated a reasonable level of precision.

The two-spotted spider mite, Tetranychus urticae, and gray mold disease caused by Botrytis cinerea, are importantpest and plant disease. To control these, many people have been relied on chemical methods for a long time. However,their continuous use has resulted in resistance of pest and disease. To surmount or avoid these problems, we evaluatedantifungal activity of the selected fungi with high virulence to mite to explore the potential for the dual control of notonly T. urticae but also B. cinerea. To maximize the use of spores and cultural filtrates, the virulence to mite was evaluatedusing culture products, and effective culture condition was investigated against blastospore production and antifungal activity.Consequently, the 2 fungal isolate selected in this study were confirmed to have diverse potential and would be usedeffectively for dual control agents against the two-spotted spider mite and plant diseases

Orius minutus (L.) (Hemiptera: Anthocoridae) is a native predators of soft body insects such as mites, thrips, and aphids.We compared 24 h consumption rate of O. minutus with that of a commercialized O. laevigatus (Fieber) on egg andadult stage of Tetranychus urticae Koch (Acari: Tetranychidae). Orius minutus predated 1.4 times more adult T. urticae(58 mites) in 24 h than O. laevigatus. Similarly, O. minutus consumed 128 eggs while O. laevigatus consumed 98 eggsin 24 h without statistical difference. These results suggest that native O. minutus can be applied for the augmentativebiological control after the development of mass-rearing method.

The two-spotted spider (Tetranychus urticae) is an important pest of many agricultural crops. Laboratory bioassayswere conducted to determine the toxicity of Pyflubumide and Cyenopyrafen against three populations of T. urticae collectedfrom apple orchards. The adults and eggs of three populations all showed susceptibility to Pyflubumide and Cyenopyrafen,as the 50% lethal concentration (LC50) values were all lower than each of the recommended concentrations. There wereconsiderable differences in susceptibility of the acaricides between eggs and adults in different populations. Pyflubumideshowed highest toxicity to adults of Yeongju population (LC50 = 1.40 mg/l) and eggs of Andong population (LC50 =0.54 mg/l). Cyenopyrafen showed lowest toxicity to adults of Andong population (LC50 = 20.29 mg/l) while displayedhighest toxicity to their eggs (LC50 = 2.64 mg/l). These results suggested that T. urticae had not developed resistancein these three regions, Pyflubumide and Cyenopyrafen can serve as alternative chemical candidate for integrated mite managementin apple orchards.

Amblyseius eharai is a native predatory mite in Korea and a candidate of biological control agent to control spidermites. To evaluate the predation ability of A. eharai, its functional response was tested at 10, 30, 50, 70 and 130 larvaeof Tetranychus urticae. A. eharai showed the Type 2 functional response. The attack rate of female and male A. eharaiwas 0.109 and 0.019, respectively. The handling time of female and male was 0.164 h and 0.234 h, respectively. Theattack rate was significantly different between male and females at 95% confidence interval. However, handling time wasnot statistically different. In comparison with Neoseiulus californicus, attack rate and handling time of A. eharai werebetter than N. californicus. These result should be helpful for evaluation of A. eharai for a biological agent against T.urticae.

This study was conducted from November 2016 to March 2017 for the development and evaluation of the biologicalcontrol of the two spotted mite (Tetranychus urticae; TSSM) in the strawberry greenhouses. Natural enemy plot and conventionalplot were selected to compare the mean density of T. urticae. T. urticae was sampled by taking three leaflets (1 stalk)from each plant (3 three-leaflet) leaves from each sampling position. Natural enemy plot was released with Phytoseiuluspersimilis and conventional plot was sprayed with pesticides(abamectin, cyenopyafen, etc). Each stage of TSSM densitywas higher in conventional pesticides than natural enemy. Spatial Analysis by Distance IndicEs (SADIE) was used toanalyze spatial distribution and index of aggregation   , index of clustering  ,   were used to investigate the spatialdistribution. Also, the clustering indices were mapped as red-blue plot. As a result, The spatial distribution of T. urticaewas varied, particularly, feeding ability and density of P. persimilis caused regular spatial distribution of T. urticae.

Ethyl formate (EF) and phosphine (PH3) is an alternative fumigant to methyl bromide (MB). For applying import sweet pumpkins in Korea, the efficacy of EF and PH3 was evaluated on Tetranychus urticae adult and egg stage which is pest in sweet pumpkins. The eggs of T. urticae were more tolerance than adults in both EF and PH3. When T. urticae eggs were treated with EF for 4 hrs, LCT99=107.63 mg/L and LCT99=45.37 mg/L at 5°C and 20°C, respectively. PH3 treatment at 5°C and 20°C for 24 hrs, eggs were controlled LCT99=49.44 mg/L and LCT99=17.23 mg/L, respectively. The mixed treatment of EF and PH3 showed no significant synergistic effect on T. urticae. However, EF (80 mg/L) and PH3 (4 mg/L) treatment did not cause any external phytotoxicity damages in sweet pumpkin even when treated with the maximum amount of fumigant at 5℃ and 20℃ for 24hrs.

It has been proved that agroinfiltration-based temporary expression of coatomer subunit alpha (COPA) gene from Tetranychus urticae hairpin RNA induces RNA interference (RNAi) and lethality to T. urticae. To establish detailed protocols for agroinfiltration, the efficiency of agroinfiltration to the soybean and kidney bean was determined with respect to different Agrobacterium delivery methods (sea sand, carborundum and syringe) and the spacial expression patterns of hairpin RNA was investigated following Agrobacterium delivery. Sea sand and syringe showed the highest expression level in soybean and kidney bean, respectively. Considering the resulting tissue damage, syringe appeared the best choice for agroinfiltration in both soybean and kidney bean. The apical region of a leaf showed more relative expression levels in both soybean and kidney bean compared to the basal region. Following agroinfiltration, adjacent untreated leaves were determined to express hairpin RNA though the expression level was low, suggesting that hairpin RNA can be translocated to other leaves. In conclusion, Agrobacterium delivery by syringe and use of whole leaf were recommended for T. urticae bioassay following agroinfiltration.

The two-spotted spider mite, Tetranychus urticae Koch (TSSM)(Acari: Tetranychidae) is the major arthropod pest in strawberry greenhouses. Elevated levels of stress caused by high populations of TSSM can lead to a significant reduction in vegetative growth and flower development, which can decrease the quality and quantity of mature fruits. Currently, TSSM is managed by pesticide, and which makes that is distributed all over the world with various pesticide resistances and environmental side effects. To solve these problems, alternative pest management strategies are being tried. Biological control, one of alternative strategies, is relatively low toxicity and stable to agricultural ecosystems. I compared the density of TSSM in export strawberry greenhouses, those are under conventional pesticides and natural enemy applied, respectively, and also evaluated the cost of management of each control strategy.