Judul: The Potential of Bintaro Leaf Infusion for Controlling Meloidogyne incognita and the Growth of Okra
Abstrak: Meloidogyne incognita adalah salah satu nematoda parasit penting yang menyebabkan puru akar pada tanaman okra (Abelmoschus esculentus). Penggunaan seduhan daun bintaro (Cerbera manghas) diharapkan dapat menjadi alternatif dalam pengendalian nematoda puru akar yang lebih ramah lingkungan, karena bintaro mengandung senyawa bioaktif yang dapat dimanfaatkan sebagai nematisida nabati. Tujuan penelitian ini adalah mengevaluasi potensi seduhan daun bintaro dalam pengendalian Meloidogyne incognita in vitro serta pengaruhnya terhadap pertumbuhan okra. Daun bintaro dihaluskan dengan blender, direndam dalam larutan bekatul dan air lalu diinkubasi dengan cara aerasi dan tanpa aerasi selama tiga minggu. Setelah tiga minggu hasil seduhan disaring dan siap digunakan untuk pengujian. Konsentrasi seduhan yang digunakan dalam penelitian ini adalah 25%, 50%, dan 75%. Hasil pengujian in vitro menunjukkan bahwa seduhan daun bintaro dapat menyebabkan kematian M. incognita sebesar 25-100% pada 24 JSP. Pengaplikasian seduhan daun bintaro tidak bersifat toksik terhadap tanaman okra. Perlakuan BA 75% dan BN 75% mampu meningkatkan berat basah dan berat kering tanaman lebih baik dari perlakuan kontrol. Hasil dari penelitian ini seduhan daun bintaro bersifat toksik bagi M. incognita dan berpotensi bila dikembangkan menjadi bionematisida., Meloidogyne incognita is one of the important plant parasitic nematodes which causes root-knot in okra (Abelmoschus esculentus). Various strategies have been developed to control the root knot nematode (Meloidogyne spp) including application of botanical pesticides. The use of bintaro (Cerbera manghas) leaf infusion is expected to be an alternative for controlling root-knot nematodes. Bintaro contains bioactive compounds that can be used as a bionematicide. This research aims was to evaluate the potential of bintaro leaf infusion in controlling Meloidogyne incognita in vitro and their effects on the growth of okra. Bintaro leaves were blended, soaked in rice bran and water solution then incubated by aerated and non-aerated condition for three weeks. The infusions were filtered and stored in room temperature. The concentrations of infusion were used in this istudy are 25%, 50%, and 75%. The result showed that under in vitro test bintaro leaf infusions caused percent mortality of Meloidogyne incognita from 25% up to 100% in 24 hours after treatment. Application of infusion of bintaro leaf has no phytotoxic effect on okra. Treatment with BA 75% and BN 75% were able to increase wet weight and dry weight of okra. This research indicates that infusion of bintaro leaf have potential to be developed as a bionematicide.
Keyword: bioactive compound, bintaro, bionematicide, Meloidogyne incognita

Judul: Eksplorasi Bakteri Endofit Asal Tanaman Lamtoro (Leucaena leucocephala L.) sebagai Agens Biokontrol Nematoda Puru Akar (Meloidogyne spp.) pada Tanaman Okra (Abelmoschus esculentus L. Moench)
Abstrak: Nematoda puru akar Meloidogyne spp. merupakan nematoda parasit penting pada okra yang menyebabkan kehilangan hasil dan kerugian secara ekonomi. Gejala yang disebabkan oleh Meloidogyne spp. yaitu tanaman kerdil, layu, daun menguning, dan akar berpuru. Meloidogyne spp. dapat berinteraksi dengan patogen lain seperti Fusarium oxysporum. Tujuan dari penelitian ini adalah mendapatkan bakteri endofit asal tanaman lamtoro yang berpotensi sebagai agen biokontrol terhadap Meloidogyne spp. dan mengetahui pengaruhnya terhadap pertumbuhan tanaman okra (Abelmoschus esculentus). Bakteri endofit diisolasi dari akar dan batang tanaman lamtoro menggunakan metode sterilisasi permukaan dengan NaOCl 1% dan alkohol 70%, kemudian dikulturkan pada media tryptose soy agar (TSA). Isolat bakteri endofit diseleksi keamanan hayatinya menggunakan uji agar darah dan uji hipersensitif. Isolat bakteri endofit terpilih dilakukan uji in vitro terhadap juvenil 2 Meloidogyne spp., cendawan Fusarium oxysporum dan diuji keefektifannya dalam penekanan puru akar pada tanaman okra di rumah kaca. Hasil penelitian diperoleh sebanyak 411 isolat bakteri endofit berhasil diisolasi dari akar dan batang tanaman lamtoro. Hasil uji keamanan hayati sebanyak 5 isolat bakteri endofit tidak berpotensi patogen terhadap mamalia maupun tumbuhan. Hasil pengujian secara in vitro terhadap juvenil 2 Meloidogyne spp. menunjukan bahwa 5 isolat bakteri endofit tersebut mampu menyebabkan mortalitas pada juvenil 2 Meloidogyne spp. berkisar antara 81.67%-98.67% dan menghambat pertumbuhan F. oxysporum berkisar antara 27.33%-45%. Perlakuan bakteri endofit mampu meningkatkan bobot tajuk tanaman okra, menekan keparahan penyakit berkisar antara 69.23%-76.92% dan menekan populasi nematoda berkisar antara 60%-71.41% pada percobaan di rumah kaca. Hasil identifikasi molekuler ke 5 isolat bakteri endofit tersebut meliputi Providencia vermicola (AD7), Providencia rettgeri (AD16 dan BGB21), Proteus vulgaris (AGB40) dan Alcaligenes faecalis (AS8), Nematodes (Meloidogyne spp.) on Okra (Abelmoschus esculentus L. Moench. Supervised by ABDUL MUNIF Root-knot nematodes (Meloidogyne spp.) is a plant parasitic nematode on Okra that causes of yield and economic losses. Symptoms caused by Meloidogyne spp. namely dwarf plants, withered, yellowed leaves, and rooted roots. Meloidogyne spp. can interact with pathogens such as Fusarium oxysporum. The objective at this research was to obtain endophytic bacteria from lamtoro plants as biocontrol agents that have the potential to control Meloidogyne spp. and to study the effects on the growth of okra plants (Abelmoschus esculentus). Endophytic bacteria were isolated from the roots and stems of the lamtoro plant using the surface sterilization method with 1% NaOCl and 70% alcohol, then cultured on tryptic soy agar (TSA) media. Endophytic bacterial isolates were selected for their biological safety using blood agar tests and hypersensitivity tests. Selected endophytic bacterial isolates were tested in vitro against juvenile 2 Meloidogyne spp., Fusarium oxysporum fungi and tested for their effectiveness in suppressing the root gall in okra plants in greenhouses. The results showed 411 endophytic bacterial isolates were successfully isolated from the roots and stems of the lamtoro plants. After biological safety test, 5 endophytic bacterial isolates were not potentially pathogenic to mammals or plants. Under in vitro showed 5 endophytic bacterial isolates were able to cause the percent mortality of juvenile 2 Meloidogyne spp. from 81.67%-98.67% and could inhibit the growth of F. oxysporum from 27.33%-45%. The treatment of endophytic bacteria was able to increase the fresh weight of
Keyword: Alcaligenes, Proteus, root gall, growth promoting, Providencia, Biocontrol Agents, Meloidogyne spp, Abelmoschus esculentus, Leucaena leucocephala, Lamtoro, okra

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.
Keyword: