에틸포메이트는 살충 효과가 빠르고 환경에 무해하며 특히 인축독성이 낮아 검역용 훈증제로 등록되어 있다. 이러한 에틸포메이트를 이용하여 훈증 챔버 (0.275 m3) 내에서 4종의 농업 해충 (오이총채벌레, 담배가루이, 복숭아혹진딧물, 점박이응애)과 4종의 작물 (참외, 오이, 토마토, 고추) 유묘기를 대상으로 12시간 훈증 처리하여 약효와 약해를 평가하였다. 에틸포메이트 1.5 g/m3의 약량으로 12시간 훈증 했을 때 담배가루이와 복숭아혹진딧물은 93.3% 이상의 높은 살충력를 나타내었으나, 점박이응애는 2.0 g/m3 약량에서도 20% 미만의 낮은 살충력을 나타내었다. 그리고 에틸포메이트의 CT값(농도ⅹ시간)이 훈증 처리 온도 20 ± 1.5℃에서 8.9 g･h/m3 이상일 때 점박이응애를 제외한 나머지 3종의 해충에 대해서 90% 이상의 살충 효과를 얻을 수 있었다. 에틸포메이트 1.5 g/m3의 약량으로 상기 4작물을 12시간 훈증했을 때 약해 증상은 나타나지 않았다. 따라서 에틸포메이트 훈증기술은 시설 내 해충방제를 위한 새로운 방식이 될 수 있으며 관행적인 살충제의 사용을 줄일 수 있을 것으로 생각된다. 그러나 해충의 충태별, 작물의 생육 시기별 에틸포메이트 약효 및 약해에 대한 많은 연구가 이루어져야 할 것으로 생각된다.

Spotted wing drosophila (SWD), Drosophila suzukii (Diptera: Drosophilidae), is an important quarantine insect pest on blueberry and strawberry exportation in Korea. Due to IPPC recommendations of replacement of methyl bromide (MB) and recent critical issue about its chronic inhalation toxicity to fumigator and related workers along with post-fumigation, alternatives to MB is urgently required. Thus, we evaluated efficacies of ethyl formate (EF) to SWD eggs using two different bioassay methods; using eggs oviposited on artificial diet and on blueberries naturally infested with SWD adults. In results, there was no differences between two bioassay methods in terms of LCT99 value of EF.

Methyl bromide (MB) has been still routinely used in quarantine fumigation on imported citrus, although there had been issuing chronic inhalation toxicity to fumigators and related workers as well as phytotoxic damages after fumigation. Ethyl formate (EF), is the only option to replace MB in terms of its safety for consumers (food additive and naturally occurred) and worker with higher threshold level limit (TLV = 100 ppm). Its application technology also provide cost effectiveness, good commercial practice in terms of application time (< 10 min) for 40 ft container. The replacement of MB with EF is recommended not to fumigate with hazardous and phasing-out MB on imported oranges.

A study on the weight reduction of a motor shaft in electric vehicle by using optimum design technique was carried out. The structural analysis of a motor shaft was performed by using ANSYS to investigate the structural safety. We also used HEEDS to find the optimal hollow shaft thickness. When the material of the hollow shaft is changed to SCM822H by using ANSYS 14.5 and HEEDS MDO, the weight could be reduced by about 53 % compared to the conventional solid one. From this study, the optimized dimensions of a hollow shaft were determined for light weight design.

To replace hazardous methyl bromide (MB) post-fumigation on imported fruits, due to insufficient ventilation process in industrial practice, alternative fumigation with liquid ethyl formate (EF) with N2 application, which is multi benefits to safe to workplace and environment, has been developed by APQA. Although EF was found to be shown proven efficacy to invasive external feeders such as mealybugs and scales on export and imported fruits and vegetables, there was still some conflicts to accept one of the phytosanitary disinfestation method somewhere because of on reliable and confirmative studies on between MB and EF in terms of efficacy to mealybugs on perishable commodities. In here, we evaluated comparative efficacy of EF and MB to target citrus mealybug, which was seems to be hard control pest, based on the current disinfestation guideline of them in Korea. The potential benefits of using liquid ethyl formate (EF) for future quarantine use could provide for safer workplace involved on and post-fumigation such as cold and packing storages, cost-effectiveness as well as meet the environmental friendly solution.

The existing ethyl formate fumigant is carbon dioxide (CO2) mixed liquified gas in metal cylinder, but this product type costs a lot to manufacture, translate and maintain cylinder. To supplement these problems, we have developed a new ethyl formate fumigation technique with nitrogen (N2) carrier. We assessed the susceptibility of mealy bugs, the most frequently detected pests in imported banana, and phytotoxicity of banana fruits. Ethyl formate and nitrogen were concurrently treated on citrus mealybug, one of the most resistant mealybug to fumigant, and ethyl formate was treated with LC50 product of independent treatment dosage. Nitrogen was treated with 7 dosages from 79% to 95% concentration. Phytotoxicity of banana was assessed by treating EF 35 mg/L with N2 79% for 14 days, and color, sugar contents and loss of weight were measured. EF with N2 treatment showed more than 50% of mortality on every growth stages, and there was no significant difference between control and treatment banana fruits. These results indicate that concurrent treatment of EF and N2 can be used to control mealybug in banana fruits.

Ethyl formate (EF) fumigation under green house condition is a new concept. Its concentrations inside and surrounding of the glass house (GH) and vinyl house (VH) were evaluated for 4 h (during daytime) and 12 h (during nighttime) after fumigation along with the evaluation of post-fumigation EF concentrations. The cumulative EF concentration × time (Ct) value of the 6 sampling positions in VH were 22.67 and 17.53 g·h/m3, respectively for day and night fumigation, which were 2.62 and 4.53 g·h/m3 respectively for day and night application in GH. The EF level (PPM) outside the VH and GH as well as after 20-min post fumigation were < 50 ppm revealing its safety level as its’ threshold limit value (TLV) is 100 ppm. The new technology using liquid EF fomulation could be a key option in smart-farm technologies in future. (Supported by PJ0133562018, RDA)

It is uncommon to fumigate the live plants in quarantine. Ethyl formate (EF) fumigation was carried out in a 0.275 m3 chamber in laboratory for 12 h (over-night) to evaluate the mortality of 4 insect pests and to evaluate the phyto-toxic effect on their host plants. The tested doses were 1, 1.5 and 2 mg/L EF with or without nitrogen gas (N2). The phytotoxicity was evaluated 7 days post-fumigation based on the damage index (DI) scaling 0-4. Mortality >80% were recorded against thrips, whitefly and aphid in all the EF or EF + N2 treatments. Two-spotted spider mite was highly tolerant (<20% mortality at the highest dose tested) to EF. Except for perilla and sesame (DI = 4), EF was non-toxic to other vegetable crops at 1.5 mg/L EF. However, 1.5 mg/L EF+N2 increased DI by 3 for tomato, watermelon and green pumpkin. This new method fumigating live plants certainly demands lots of further experiments to ensure its practical application in farm level. (Supported by PJ0133562018, RDA)

This study investigated the fumigant activity of phosphine (PH3) on 2 kinds of mealybug (Pseudococcus longispinus and P. orchidicola (Hemiptera: Pseudococcidae)) adults and nymphs. All of the two mealybugs adults showed higher LCT99 values than nymphs, and P. longispinus showed higher tolerance than P. orchidicola in a 12 L desiccator. The absorption of phosphine on 13 nursery plants showed 12.2~41.5% difference depending on the plant. All of the mealybugs treated with phosphine 2 mg/L in 0.5 m3 fumigation chamber for 4 h showed 100% fumigant activity, except P. longispinus adult (approximately 90% at bottom part). However, when the exposure time was increased to 24 h, all of them showed 100% mortality. In the treatment of 10 m3 container, the 24 h treatment of phosphine showed 100% mortality to P. longispinus and P. orchidicola adults and nymphs. In all the experiments, no phytotoxicity of phosphine observed on 13 plants until 1 month after treatment.

A combination using phosphine (PH3) and ethyl formate (EF) was performed to compensate for the disadventages (long exposure time and phytotoxicity) of a single substance. P. longisipinus was more susceptible to mixed phosphine and ethyl formate than P. orchidicola in 12 L dessicator. Mortality of mixed treatment was higher than aggregated mortalities that treated individually, so it indicated to have a synergic effect on each other. Ethyl formate was showed higher adsorption rate than phosphine on imported nursery plants and showed differences depending on the plant. P. longispinus and P. orchidicola was showed 100% mortality when phosphine and ethyl formate was treated as 1 g/m3 and 30 g/m3 for 4 hour in 0.5 m3 fumigation chamber and in 10 m3 container. Phytotoxicity was evaluated to mixture of phosphine and ethyl formate at 1 month after treatment.

Methyl bromide (MB) had been routinely used in quarantine and pre-shipment (QPS), despite of strong recommendations to replace technically feasible alternatives of it by International Plant Protection Convention (IPPC) and current hazardous issues in workplace related post-fumigation process of imported perishable commodities. Due to insufficient ventilations post-fumigation on imported fruits such as citrus, fumigators and related workers in cold storage, load/unload and packing room has been exposed to hazardous conditions (5-100 ppm, MB’s TWA_TLV = 1 ppm). It’s time to replace newly developed phytosanitary disinfestation methods such liquid ethyl formate (EF) with N2 application. It could provide for safer workplace involved on and post-fumigation process, cost-effectiveness as well as meet the environmental friendly solution.

Phosphine (PH3) resistance in the stored-products insect pests has been reported throughout the world in various insect species, including Rhyzopertha dominica, Tribolium castaneum, and Cryptolestes ferrugineus, leading farmers and fumigators to identify new fumigation tools to control PH3-resistant insect pests in storage facilities. Understanding PH3-resistance mechanisms in insects might contribute to providing clues for the development of new chemicals, including fumigants, to control various PH3-resistant insects. A proteomic study has shown 15 decreased proteins in the PH3-resistant R. dominica (CRD343 strain) in comparison to the PH3-susceptible R. dominica, and among those 15 proteins, dihydrolipoamide dehydrogenase (DLD), a protein involved in the Krebs cycle, was identified (Park et al., 2008). The DLD polymorphisms responsible for genetic resistance have disulfide active sites for PH3 binding and are highly sensitive to arsenic exposure after mutagenesis in insects (R. dominica and T. castaneum) and Caenorhabditis elegans (Schlipalius et al., 2012). Here, two PH3- resistant S. oryzae strains were used to understand the development of PH3 resistance in these insects. Acute toxicity test by PH3 on the two PH3-resistant strains was undertaken followed by ethyl formate inhibition study on cytochrome c oxidase activity. The Lineweaver-Burk plots after inhibition studies showed there were significantly difference in inhibition mode between the resistant strains and the control. The RT-qPCR analysis and the next-generation sequencing of the mitochondrial DNA revealed significant changes in metabolism and energy production. Taken together, the PH3 resistance in S. oryzae was definitely acquired by the overall transformation of biochemical reactions to overcome PH3 toxicity.

알락하늘소(Anoplophora chinensis)와 유리알락하늘소(A. glabripennis)는 전 세계적으로 검역상 중요한 하늘소과 해충이다. 우리나라에서 이들은 자연 기주목과 분재에서 피해를 주고 있다. 본 연구에서는 분재에서 phosphine의 이들 두 하늘소에 대한 방제효과를 조사하였다. Phosphine은 솔수염하늘소 유충과 알에 대해 높은 훈증효과를 보였다. 2 g/m3 농도의 phosphine을 24시간 훈증처리 시 유리알락하늘소와 알락하늘소 난은 부화하지 못하였고, 알락하늘소 유충은 동일농도에 168시간 훈증처리 시 100% 치사되었다. 분재 생육기(2월)나 휴면기(1월) 모두에서 phosphine 훈증제는 2 g/m3 농도에서 두 알락하늘소를 100% 치사시켰다. 그러나 2월에 각 분재목[단풍나무(Acer palmatum)와 소사나무(Carpinus turczaninowii), 아그배나무(Malus sieboldii)]을 대상으로 훈증처리 시, 세 수종 모두에서 잎과 꽃잎의 크기가 작아지고, 꽃의 개화가 지연되는 약해가 발생되었다.