Tomato yellow leaf curl virus (TYLCV) and its vector insect, the sweet potato whitefly Bemisia tabaci, are major threats to tomato and pepper production in all around world. Since the last three decades, both B. tabaci and TYLCV have been invaded into many countries via different routes. Our studies showed that various geminiviruses including TYLCV can be transmissible by seeds as well as whiteflies. Furthermore, commercially developed resistant tomato strains against TYLCV infection can serve as TYLCV reservoirs and potentially influence on TYLCV epidemics. Therefore, transmission pathways through both insect vectors and seeds should be concerned for suitable management of geminiviruses and whiteflies.

As social media penetrates more deeply into people’s everyday lives, social commerce (a type of commerce that combines SNS features and possibility for commercial transactions) has enjoyed unprecedented growth. Shopping on Facebook is a representative example of social commerce platform that allows consumers to interact with other users, exchange information and purchase products without leaving a Facebook page. Social commerce presents great opportunities for marketers in terms of leveraging social aspects of shopping experience. It also offers a large potential for Korean companies to reach various target markets, as well as establish their presence abroad. Yet, acceptance of social commerce as a legitimate shopping channel has been slow, and consumers are still hesitant to shop via Facebook. This study draws on uses and gratification theory and the concept of perceived risk to examine how different motives for SNS use and the associated types of perceived risks can affect the purchase intention on the platform. Empirical data from 288 young users of Facebook were analyzed. Findings identified two main motives for SNS use: information-related motive and communication-related motive. Information-related motive significantly affected the intention to shop on Facebook, whereas communication- related motive did not have any significant influence. Risks associated with shopping via Facebook included delivery risk, security risk, social risk and economic risk. Overall, consumers perceived a higher level of security and social risk associated with shopping on Facebook. However, only social risk had a significant negative influence on the purchase intention. Awareness and previous experience of buying via social commerce platform positively affected consumers’ purchase intention.

La1-xBaxMnO3 (x = 0.30, 0.35 and 0.40) samples have been prepared by solid-state reaction method. The X-ray diffraction (XRD) study showed that all the samples crystallized in a rhombohedral structure with an R-3c space group. Variation of the magnetization as a function of the temperature and applied magnetic field was carried out. All the samples revealed ferromagnetic to paramagnetic (FM-PM) phase transition at the Curie temperature TC ~ 342 K. The magnetic entropy change was also studied through examination of the measured magnetic isotherms M(H, T) near TC. The magnetocaloric effect was calculated in terms of the isothermal magnetic entropy change. The maximum entropy change reaches a value of 1.192 J/ kgK under a magnetic field change of 2.5T for the La0.6Ba0.4MnO3 composition. The relative cooling power (RCP) is 79.31 J/ kg for the same applied magnetic field.

Withthe increasing trend of global trades and protection of agro-ecosystem in importing and exporting countries against quarantine pest, quarantine and pre-shipment(QPS) fumigation in perishable commodities is now more important to maintain postharvest quality until delivering to end user not just eradiation of quarantine pest. However, there are limited use of MB fumigation on export fruits and vegetables due to phytotoxic damages of fumigated one. VapormateTM, alternative to methyl bromide(MB), a gas formulation of ethyl formate(EF) with carbon dioxide, is commercially in use for imported fruits fumigation such as bananas and lemon. Herein, based on previous preliminary studies, scale-up and commercial scale fumigation of ethyl formate is presented for promising export paprika and tomato. Efficacy of ethyl formate was described in terms of concentration × time (CT) products to Myzus persicae for paprika and Bemisia tabaci for tomato.

Since Montreal protocol in1989 designated MB(methyl bromide) as ozone depleting chemicals, IPPC(International Plant Protection Convention) has adopted replacing the MB with alternative chemical and reducing the rate of MB use in plant quarantine in 2008. Pineapples are one of the most frequently fumigated imported fruit with MB in Korea. However, there was no technically available replacement. Therefore, we evaluated phosphine(PH3) fumigation as alternative to MB in applying pineapples. In the preliminary test, PH3 gas in 12L desicators to calculate ranged to 0.1 from 2g/m3 was tested at 2 and 24hr exposure to target pest, citrus mealy bug(CMB, Planococcus citri). All different of stage of CMB was shown 100% mortality when 2g/m3 of PH3 applied for 24hrs at 8℃. To confirm studies designed in 0.5m3 fumigation chamber, all egg, nymph and adult stages of CMB was killed completely and there wasn’t any phytotoxic and quality damages on pineapples for 2 weeks post-fumigation periods at 8℃. In terms of commercial use, further commercial research will need to be carry out in cooperation with importers and fumigators.

Chrysanthemum stunt viroid (CSVd) is a serious pathogen affecting chrysanthemum that has caused significant economic losses to Chrysanthemum flower production worldwide. Control of CSVd disease is difficult due to its contagious nature and long latent period in the field. As chrysanthemum is most often produced by implanting seedlings, it is necessary to diagnose CSVd infection before cultivation. In this study, we screened CSVd infection in seedlings from 30 varieties including 5 domestic, 6 Japanese, and 19 European varieties. Molecular diagnosis of the combination of RT-PCR and nested PCR showed that CSVd was not detected by the first RT-PCR but detected by the second nested PCR analysis in 10 varieties, including 1 domestic, 2 Japanese, and 7 European varieties. Further comparison of 10 identified CSVd nucleotide sequences showed that those are highly conserved (99-100%) and the most similar to an isolate (AB006737) identified in Hokkaido, Japan. Our study suggests that the combination of RT-PCR and nested PCR analysis is successful for the CSVd diagnosis of seedlings and the molecular diagnosis is necessary to prevent the introduction and propagation of viroid disease into the fields.

Vector-borne plant virus transmission is a complex mechanism involving various interactions of viruses, vectors and plants. Plant viruses modify, either directly or indirectly, the rates of development, reproduction and behavior of vector insects in a positive, negative, or neutral manner. The sweetpotato whitefly, Bemisia tabaci, is the only known vector of Tomato Yellow Leaf Curl Virus (TYLCV) which is a virus that seriously damaged tomato cultivars all around the world. Acquisition of TYLCV influences on various developmental, physiological and molecular mechanisms of Q1 biotype B. tabaci. We compared several behavioral and physiological characteristics between non-viruliferous (NV) and TYLCV-viruliferous (V) of Q1 biotype whiteflies. When B. tabaci acquired TYLCV, total life span was shorter and fecundity was lower than NV ones. V whiteflies were more susceptible to thermal stress by increasing hsp mRNA levels but higher in mortality by either heat or cold shocks. Furthermore, V whiteflies increased the rates of plant sap probing and light attraction behaviors than NV ones. All together, our results show that TYLCV acquisition regulates B. tabaci to enhance the rates of development and environmental susceptibility. Our results provide insights to understand vector’s role in relation to the acquisition and transmission of plant viruses.

겨울철 해표면 수온 및 한국 주변역 생태계의 장기 변화 특성 및 상관관계를 분석하였다. 기후 및 해양환경의 변화와 동반된 어획강도의 변화는 1970 년대 이후 어획량 증가의 주요 원인으로 나타났다. 한국 주변역의 겨울철 SST는 1980년대 후반 기후체제변환 시점을 중심으로 상대적으로 저수온에서 고수온으로 변화되었다. 평균영양단계(MTL)는 1970년대 중반 이후 지속적으로 감소하기 시작하였으며, 하위영양단계 어류의 어획량 증가가 중요 변수로 작용하였다. 통합생태계 기반 자원평가 방법중 한가지인 FIB 지수는 1970년 초부터 1970년 후반까지 증가하였으며, 이후 일정 수준을 유지하였다. 특히, 중간영양단계에 위치하는 멸치와 정어리의 개체수 변화는 1970년대 초 이후 MTL 변화의 주요 인자로 작용하였다.