We investigate two abnormal CME-Storm pairs that occurred on 2014 September 10 - 12 and 2015 March 15 - 17, respectively. The first one was a moderate geomagnetic storm (Dstmin -75 nT) driven by the X1.6 high speed flare-associated CME (1267 km s−1) in AR 12158 (N14E02) near solar disk center. The other was a very intense geomagnetic storm (Dstmin -223 nT) caused by a CME with moderate speed (719 km s−1) and associated with a filament eruption accompanied by a weak flare (C9.1) in AR 12297 (S17W38). Both CMEs have large direction parameters facing the Earth and southward magnetic field orientation in their solar source region. In this study, we inspect the structure of Interplanetary Flux Ropes (IFRs) at the Earth estimated by using the torus fitting technique assuming self-similar expansion. As results, we find that the moderate storm on 2014 September 12 was caused by small-scale southward magnetic fields in the sheath region ahead of the IFR. The Earth traversed the portion of the IFR where only the northward fields are observed. Meanwhile, in case of the 2015 March 17 storm, our IFR analysis revealed that the Earth passed the very portion where only the southward magnetic fields are observed throughout the passage. The resultant southward magnetic field with long- duration is the main cause of the intense storm. We suggest that 3D magnetic field geometry of an IFR at the IFR-Earth encounter is important and the strength of a geomagnetic storm is strongly affected by the relative location of the Earth with respect to the IFR structure.
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.
실내에서 담배거세미나방의 영기별 약제감수성을 조사한 결과 시험된 약제 모두 유충의 영기가 높아질수록 약제감수성은 낮았다. Chlorpyrifors-methyl과 chlorpyrifos의 독성은 3령부터, etofenprox+PAP와 deltamethrin은 2령부터 현저히 떨어졌다. 포트시험결과 deltamethrin을 제외한 4약제 모두 90% 이상의 방제가를 보여 담배거세미나방의 방제에 유용하게 사용될 수 있을 것으로 생각된다. 하지만 야외에서 담배거세미나방은 전 영기가 혼재되어 있고 영기별 약제감수성이 다르기 때문에 적절한 약제선택은 물론 유충 발생초기에 약제를 살포하는 것이 중요하다.
사과원에서 사용되는 살비제 5종, 살충제 4종, 살균제 6종올 추천농도로 희석하여 점박이응애와 긴털이리응애에 대한 상대독성을 엽침지법으로 실험실에서 조사하였다. Dicofol은 점박이응애와 긴털이리응애에 대해 독성이 매우 강하였으며, 이들의 난에 대해서도 각각 46%와 40%의 致死效果가 있었다. Abamectin 용액에 침지된 긴털이리응애 암컷성충의 사망율은 무처리와 차이가 없었으나 점박이응애의 암컷성충은 24시간 이내에 모두 사망하였다. Tetradifon, Clofentezine, Hexythiazox등 3종의 살란성 살비제는 점박이 응애의 난에 대해서는 90%이상의 살란효과를 나타내었으나 긴털이리응애 난의 부화에는 아무런 영향이 없었다. Teflubenzuron, Triflumuron, Diflubenzuron, lmidacloprid 등 4종의 살충제와 Propineb, Fenarimol, Polyoxin-B.captan 등 3종의 살균제는 긴털이리응애 암컷성충에 대해 살비효과가 없었으며, Chlorothalonil, Nuarimol . Mancozeb, Folpet 등 3종의 살균제도 23% 이하의 낮은 살비효과를 나타내었다. 이상과 같이 긴털이리응애 난이나 암컷성충에 저독성을 나타내는 4종의 살충제와 4종의 살비제 및 6종의 살균제는 사과원 병해충 종합관리체계에서 긴털이리응애와 함께 이용될 수 있을 것으로 생각된다.