Judul: Identification and Disease Severity of Dieback Disease on Sengon Seedlings in Persemaian Permanen Dramaga Bogor
Abstrak: Sengon merupakan salah satu komoditas tanaman kehutanan yang digemari masyarakat. Sehingga pengadaan semai sehat di persemaian sangat penting dilakukan dalam upaya mencapai keberhasilan tanam. Namun, sengon sangat rentan terhadap beberapa penyakit. Salah satu penyakitnya yaitu penyakit mati pucuk di persemaian. Penelitian ini bertujuan menghitung kejadian penyakit dan keparahan penyakit mati pucuk pada semai sengon di Persemaian Permanen Dramaga Bogorserta mengidentifikasi jenis patogen penyebab penyakit mati pucuk pada semai sengon. Metode pengambilan data dilakukan menggunakan metode sensus dan skoring. Selain itu, proses identifikasi dilakukan di bawah mikroskop cahaya dengan perbesaran 40x10. Analisis data dilakukan menggunakan analisis deskriptif. Persentase kejadian penyakit dan keparahan penyakit mati pucuk pada semai sengon berturut-turut sebesar 10,809% dan 73,764% yang mana keparahan penyakit dinyatakan berat. Berdasarkan hasil identifikasi, cendawan Rhizoctonia sp. diduga sebagai penyebab penyakit mati pucuk pada semai sengon., Sengon is one of the forestry plant commodities favored by the community. So that the provision of healthy seedlings in the nursery is significant to achieve successful planting. However, sengon is very susceptible to several diseases. One of the diseases is dieback in the nursery. This study aims to calculate the incidence and severity of shoot death in sengon seedlings in Persemaian Permanen Dramaga Bogor and identify the types of pathogens that cause dieback in sengon seedlings. Methods of data collection carried out using the census and scoring methods. In addition, the identification process carried out under a light microscope with a magnification of 40x10. Data analysis performed using descriptive analysis. The percentage of disease incidence and dieback severity in sengon seedlings were 10.809% and 73.764%, where the severity of the disease is declared as severe. Based on the identification results, the fungus Rhizoctonia sp. is suspect as the cause of dieback in sengon seedlings.
Keyword: dieback, disease severity, nursery, Rhizoctonia sp., sengon

Judul: Pathogenicity Test of Fungal Leaf Blight on Sengon Seedlings at Permanent Nursery Dramaga Bogor
Abstrak: Sengon (Paraserianthes falcataria L. Nielsen) merupakan tanaman dari famili Fabaceae yang memiliki banyak potensi, baik secara ekologi dan ekonomi untuk ditanam di lahan rehabilitasi. Penelitian ini bertujuan untuk menguji patogenisitas dan mengidentifikasi cendawan penyebab hawar daun pada bibit sengon. Metode penelitian meliputi kegiatan uji patogenisitas yang terdiri atas pengamatan lapang dan postulat Koch serta identifikasi jenis. Penelitian menggunakan Rancangan Acak Lengkap Faktorial (RALF) dengan uji ANOVA dan uji lanjut Duncan. Hasil uji postulat Koch dapat diketahui bahwa dua isolat menyebabkan hawar pada daun. Hasil uji patogenisitas dapat diketahui bahwa isolat 1 menghasilkan luas serangan dan intensitas serangan paling tinggi dan berbeda nyata dengan isolat lainnya. Hasil identifikasi dapat diketahui bahwa isolat 1 memiliki karakteristik koloni berwarna putih, terdapat sklerotium, tidak memiliki spora, sudut percabangan hifa 90°, bersekat, terdapat penggentingan hifa dekat percabangan, dan terdapat struktur moniloid. Berdasarkan karakteristik tersebut, cendawan ini merupakan Rhizoctonia sp.
Keyword: Characteristics, Koch's postulate, leaf blight, Paraserianthes falcataria, Rhizoctonia sp.

Judul: Kekonsistenan Hamiltonian pada Gerak Gelombang Interfacial
Abstrak: The interfacial wave is an internal wave that occurs at boundary of two layers fluid. It appears because there is difference of mass density between the two layers. The objective of this thesis is to formulate the motion of internal wave with flat base and flat as well as free upper bound surface. The motion equation obtained is a Hamiltonian system. The Hamiltonian in this system is expressed by variable of wave deviation and horizontal component of potential velocity. Under assumption that interfacial wave moves only in one direction, it can be shown that the Hamiltonian depends on the solution of the wave motion equation. The coefficients of the equation depend on the physical characteristics of the two layers of fluid, i.e. thickness and mass density. The numerical results show that Hamiltonian in the system is constant. It is consistent with Hamiltonian characteristic, which does not depend on time.
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