Judul: Pengaruh Tiga Macam Strategi Pengendalian Hama dan Penyakit pada Pertumbuhan dan Produksi Melon (Curcumis melo L.)
Abstrak: Melon (Curcumis melo. L) merupakan salah satu komoditas hortikultura yang perlu mendapat perhatian, karena mempunyai nilai ekonomi tinggi, dengan rasa yang enak dan aroma yang khas disukai masyarakat has. Masalah yang sering ditemui dalam budidaya melon adalah tingginya gangguan hama dan penyakit. Gangguan yang berat dapat menurunkan produksi, bahkan dapat menggagalkan panen secara total sehingga petani melon tidak segan-segan menggunakan beragam pestisida dalam jumlah yang tinggi bahkan berlebihan. Hal tersebut mengakibatkan ketidakefisienan aplikasi pestisida karena harga pestisida yang makin mahal dan terjadinya kerusakan lingkungan.
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Judul: Intensitas Penyakit Downy Mildew dan Keberadaan Hama pada Melon dengan Sistem Biointensif
Abstrak: Tanaman melon merupakan salah satu tanaman buah semusim yang memiliki nilai ekonomi tinggi, namun produksinya mengalami fluktuasi. Hama penyakit dapat menyebabkan penurunan kualitas maupun kuantitas. Pengendalian hama penyakit dengan pestisida sintetik sudah banyak digunakan dan dapat meninggalkan residu. Sehingga, perlu pengembangan produksi melon yang ramah lingkungan dengan agens hayati. Sistem biointensif menjadi salah satu solusi pengendalian hama penyakit dengan memaksimalkan pemanfaatan organisme tanah. Penelitian ini bertujuan mengetahui pengaruh sistem biointensif terhadap penyakit penting dan produksi pada dua varietas melon di Tegal. Penelitian menggunakan rancangan acak kelompok (RAK) faktorial, faktor varietas (Pertiwi dan Alisha) dan biointensif, H2 (Pseudomonas diminuta and Bacillus. firmus + Trichoderma harzianum + Lecanicillium sp. + guano) dan H3 (P. diminuta dan B. firmus + Trichoderma harzianum + Lecanicillium sp.). Metode sampling adalah zig-zag. Berdasarkan hasil pengamatan, hama yang ditemukan antara lain lalat pengorok daun, ulat, dan kumbang daun sedangkan penyakit utamanya adalah downy mildew. Hasil yang diperoleh menunjukkan sistem biointensif belum mempengaruhi produksi melon pada musim hujan, meskipun dapat menekan keparahan penyakit downy mildew lebih baik dibandingkan kontrol pada varietas Pertiwi di awal infeksi. Setiap kombinasi faktor tidak mempengaruhi keberadaan hama dengan hasil sama pada kontrol. Produksi buah melon terbaik diperoleh pada varietas Alisha dengan perlakuan H3, Melon is one of the annual fruit plants that have high economic value, but their production fluktuates. Pests and diseases can cause a decrease in quality and quantity. Pest and disease control using synthetic pesticides is widely used and can leave residues. This causes need to develop more environmentally friendly melon production by using biological agents. Biointensive system is one of the solutions in pest control with by maximizing the utilization of beneficial microorganisms. This research aim was to determine the effect of biointensive systems on important pests and diseases and production of two melon varieties in Tegal. The study applied a factorial randomized group design, with factors related to varieties (Pertiwi and Alisha) and treatment, i.e. H2 (Pseudomonas diminuta and Bacillus firmus + Trichoderma harzianum + Lecanicillium sp. + guano) and H3 (P. diminuta dan B. firmus + Trichoderma harzianum + Lecanicillium sp.). The sampling applied was zigzag method. Based on observations, the pests found on melon plants include leafminer, caterpillars, and leaf beetles while the main disease is downy mildew. The result obtained show that the biointensive systems has not been able to affect melon production in the rainy season, although it can suppress the severity of downy mildew disease better than control on Pertiwi variety during earlier phase of infection. Each combination of factors does not affect the presence of pests and no differences with the control. The best melon fruit production is obtained on the Alisha variety with H3 treatment.
Keyword: Biocontrol agents, Bacillus firmus, downy mildew, pest attack, Pseudomonas diminuta

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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