Judul: Uji kisaran inang dan deteksi virus penyebab mozaik pada tanaman bengkuang (Pachyrrhizus erosus L. Urban)
Abstrak: Penelitian ini bertujuan mengidentifikasi virus penyebab mozaik pada tanaman bengkuang dengan menguji kisaran inang dan mendeteksi secara serologi, serta pengamatan partikel virus dengan mikroskop elektron. Survei kejadian penyakit mozaik bengkuang di beberapa pertanaman bengkuang di Darmaga, Bogor menunjukkan bahwa virus ini telah tersebar di semua lokasi pengamatan (Cibeureum, Situ Gede, dan Babakan Raya) dengan intensitas serangan bervariasi antara 14,16-100%.
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Judul: Deteksi benih dan penularan virus mosaik bengkuang oleh tiga spesies kutudaun
Abstrak: Virus mosaik bengkuang adalah virus yang banyak ditemukan di pertanaman bengkuang di daerah Bogor dan sekitarnya. Di lapangan intensitas serangan virus ini cukup tinggi. Virus ini belum terkarakterisasi sifat biologinya, maka informasi tentang penularan virus di lapangan perlu diketahui sebagai dasar untuk penentuan strategi pengendalian. Penelitian ini bertujuan untuk mengetahui penularan virus mosaik bengkuang oleh tiga spesies kutudaun dan mengetahui penularan virus melalui benih. Penularan virus dilakukan dengan menggunakan tiga spesies kutudaun, yaitu Aphis craccivora Koch., A. glycines Mats., dan A. gossypii Glov. Setelah diidentifikasi dan dibebasviruskan pada daun talas, kutudaun dibiakkan pada tanaman inangnya, yaitu kacang panjang, kedelai dan cabai. Tanaman bengkuang diinokulasi dengan masing-masing vektor sebanyak 10 kutudaunltanaman. Sebelumnya kutudaun itu dilaparkan selama I jam dan diberi makan akuisisi ke tanaman bengkuang sakit selama 1 jam dan makan inokulasi selama 24 jam pada bengkuang sehat. Parameter yang diamati adalah masa inkubasi, kejadian penyakit, dan tipe gejala. Untuk mengetahui apakah virus terbawa benih, dilakukan deteksi benih yang berasal dari pertanaman bengkuang dari daerah Cibungbulang dan Cibeureum (Jawa Barat), dan Prapat (Jawa Timur). Benih ditumbuhkan terlebih dahulu, daun-daun muda yang muncul kemudian diambil sebagai sampel komposit (10 tanama~Jsampel)d an virus dideteksi dengan metode DIBA (Dot imrnunobinding assay), menggunakan antiserum BCMV (Bean Conzrnon Mosaic Virus, DSMZ-Jermanj. Masing-masing lokasi diuji sebanyak 100 benih (10 sampel).
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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