Judul: Biological Control Agent Products for Control of Plant Diseases
Abstrak: Penyakit tanaman dapat menurunkan hasil panen mencapai 25% per tahun. Pengendalian penyakit tanaman dengan agens hayati sangat disarankan karena bersifat selektif, aman bagi manusia, dan lingkungan. Penelitian ini bertujuan menyusun informasi terkait produk agens hayati untuk mengendalikan penyakit tanaman dari berbagai jenis mikroba yang telah beredar di pasaran baik produk dari dalam maupun luar negeri. Penelitian dilakukan dengan kajian pustaka secara daring pada Google, Google cendekia, ReserachGate, ScienceDirect, dan Repository IPB. Diketahui terdapat 273 merek dagang produk agens hayati untuk mengendalikan penyakit tanaman di pasaran yang disusun berdasarkan 118 sumber pustaka ilmiah. Jumlah merek tersebut mencakup 15 merek lokal dan 258 merek dari luar negeri. Produk ini terdiri dari 129 jenis bakteri, 138 jenis cendawan, dan enam jenis virus, sedangkan produk dari jenis nematoda belum ada, tetapi penelitian mengenai spesies nematoda yang berpotensi seperti Monochochus aquaticus, Aphelenchus avenae, dan Mesorhabditis sp. telah banyak dilaporkan. Mayoritas produk menekan patogen tanaman dengan mekanisme antibiosis. Produk dapat diaplikasikan dengan cara biopriming, pencelupan bibit, penyemprotan daun, dan aplikasi pada tanah. Jumlah produk dan minat masyarakat terhadap produk agens hayati masih sedikit, tapi diperkirakan akan terus meningkat seiring banyaknya program pelestarian lingkungan dan sistem pertanian organik. Kata kunci: antibiosis, pertanian organik, produk komersial, priming, Plant diseases can reduce crop yields by 25% per year. Control of plant diseases with biological agents is highly recommended because they are selective and safe for humans, and the environment. This study aims to compile information related to biological agent products to control plant diseases from various types of microbes that have been available in the market, both domestic and foreign products. The research was conducted using an online literature study on Google, Google Scholar, ResearchGate, ScienceDirect, and the IPB repository. Based on this study there are 273 trademarks of biological agents products for controlling plant diseases in the market which are compiled based on 118 scientific literature sources. The number of brands includes 15 local brands and 258 brands from abroad. These products consist of 129 types of bacteria, 138 types of fungi, and six types of viruses, while the products of the nematodes type do not yet exist, but research on potential nematode such as Monochochus aquaticus, Aphelenchus avenae, and Mesorhabditis sp. has been widely reported. The majority of mode action in suppressing plant pathogens is antibiosis mechanisms. The product can be applied using biopriming, seed dip, foliar spray, and soil application. The number of products and public interest in the products of biological agents is still small, but is expected to continue to increase in line with the number of environmental conservation programs and organic farming systems. Keywords: antibiosis, commercial product, organic farming, priming
Keyword: Antibiosis, Pertanian organik, Produk komersial, Priming

Judul: Test the Potential of Antagonistic Microbes as Biocontrollers of Plant Disease Causes
Abstrak: Pengendalian hayati merupakan alternatif untuk mengurangi penggunaan pestisida karena dapat menekan pertumbuhan patogen tanaman dan tidak berdampak negatif terhadap lingkungan. Tujuan penelitian ini yaitu menguji efektivitas mikrob antagonis sebagai pengendali hayati penyebab penyakit tanaman. Pada penelitian ini menggunakan tiga mikrob antagonis (Trichoderma sp., Gliocladium sp., Bacillus sp.) dan tiga cendawan patogen uji (Rhizoctonia sp., Sclerotium sp., Botryodiplodia sp.). Penelitian ini terbagi menjadi tiga percobaan, yaitu (1) uji antagonis secara in vitro, (2) uji metabolit sekunder dan (3) uji pertumbuhan pada benih sengon (in vivo). Parameter yang diukur berupa persentase penghambatan, daya kecambah, kecepatan tumbuh, kejadian penyakit, dan intensitas penyakit. Cendawan Trichoderma sp. dan Gliocladium sp. mampu menghambat pertumbuhan cendawan patogen Sclerotium sp., Rhizoctonia sp., dan Botryodiplodia sp. berkisar 61,82% hingga 80,00%. Metabolit sekunder cendawan Gliocladium sp. lebih mampu menghambat pertumbuhan miselia cendawan patogen Rhizoctonia sp., Sclerotium sp., dan Botryodiplodia sp. dibanding cendawan Trichoderma sp. dengan nilai penghambatan berturut-turut adalah 71,13%, 33,83%, 23,58%. Gliocladium sp., Trichoderma sp., dan Bacillus sp. mampu menekan kejadian penyakit (14,29%, 12,38%, dan 15,24%) dan intensitas serangan damping-off yang disebabkan Rhizoctonia sp. (8,91%, 8,57%, dan 9,43%). Hal ini ini menunjukkan agensia hayati berpotensi mengendalikan penyakit tanaman.
Keyword: agensia hayati, damping-off, metabolit sekunder, Trichoderma

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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