Judul: Potential of Biological Agents in Controlling Ganoderma sp. in Sengon Stands on Post Mining Land, North Kalimantan
Abstrak: Reklamasi menggunakan tanaman sengon pada lahan PT. Pesona Khatulistiwa Nusantara masih rentan terhadap serangan hama dan penyakit. Jenis penyakit yang umum ditemukan pada tanaman sengon adalah penyakit busuk akar merah yang disebabkan oleh cendawan patogen Ganoderma sp. Penelitian ini bertujuan menganalisis pengaruh agens hayati yaitu, cendawan Trichoderma sp. dan cendawan JakabaBHP01 dalam menghambat pertumbuhan cendawan Ganoderma sp. serta menganalisis pengaruh waktu dalam proses penghambatannya. Uji antagonis dilakukan dengan menggunakan metode kultur ganda antara cendawan patogen dan cendawan antagonis pada media Potato Dextrose Agar (PDA). Perlakuan pengaruh waktu dilakukan dengan dua cara : a) penumbuhan Ganoderma sp. dan cendawan antagonis secara bersamaan dan b) menumbuhkan terlebih dahulu Ganoderma sp. selama 7 hari sebelum diuji daya hambatnya terhadap cendawan antagonis. Hasil uji antagonis menunjukkan bahwa Trichoderma sp. dan JakabaBHP01 dapat menghambat pertumbuhan patogen dengan waktu peletakkan yang dilakukan bersamaan. Hasil penghambatan tertinggi pada Ganoderma sp. A1 adalah perlakuan dengan menggunakan Trichoderma sp. dengan persen penghambatan sebesar 95,63% dan pada Ganoderma sp. A2 perhambatan tertingginya juga dengan perlakuan Trichoderma sp. yaitu sebesar 98,74%. Mekanisme penghambatan pada Trichoderma sp. adalah mekanisme kompetisi dan pada JakabaBHP01 adalah mekanisme mikoparasitisme., Reclamation using sengon plants on PT. Pesona Khatulistiwa Nusantara was still vulnerable to pest and disease attacks. The type of disease commonly found in sengon plants was red root rot disease caused by the pathogenic fungus Ganoderma sp. This research aims to analyze the influence of biological agents, namely, the fungus Trichoderma sp. and the JakabaBHP01 fungus in inhibiting the growth of the Ganoderma sp fungus. and analyze the influence of time in the inhibition process. The antagonist test was carried out using a double culture method between pathogenic fungi and antagonist fungi on Potato Dextrose Agar (PDA) media. The influence of time was treated in two ways: a) growing Ganoderma sp. and antagonistic fungi simultaneously and b) grow Ganoderma sp. for 7 days before testing its inhibitory power against antagonistic fungi. Antagonist test results showed that Trichoderma sp. and JakabaBHP01 can inhibit the growth of pathogens with simultaneous laying times. The highest inhibition results on Ganoderma sp. A1 was a treatment using Trichoderma sp. with percent inhibition of 95.63% and in Ganoderma sp. A2 also had the highest inhibition with Trichoderma sp. namely 98.74%. Inhibitory mechanisms in Trichoderma sp. was a competition mechanism and in JakabaBHP01 it was a mycoparasitism mechanism.
Keyword: Trichoderma sp., antagonistic fungi, mechanism, JakabaBHP01

Judul: Potensi Trichoderma spp. Sebagai Agens Hayati dalam Pengendalian Ganoderma sp. yang Menyerang Tanaman Sengon
Abstrak: Sengon (Falcataria mollucana) is one of the forestry plant that widely developed by the community of Indonesia farmers especially in Java Island. Nowadays, sengon is widely planted with a monoculture system, therefore emerging many serious problems in silvi-culture. One of the serious problems was attacked by the pathogenic fungi, Ganoderma sp., which mainly caused root rot diseases. This research was aimed to investigate the ability of Trichoderma spp. in controlling the in vitro growth of Ganoderma sp. and to evaluate the capability of T. harzianum in inhibiting the growth of Ganoderma sp. on sengon timber substrate at greenhouse. This research was carried out in three experimental stages as follow: stage 1: study the growth activity of Ganoderma sp.; stage 2: study the inhibition activity of Trichoderma spp. towards the growth of Ganoderma sp. and stage 3: control the growth of Ganoderma sp. on Sengon timber substrate at greenhouse. Our results showed that the growth rate of Ganoderma sp. was expert on PDA and MEA medium each 12 days and 14 days incubation, respectively. Afterwards, the petridish was full of the Ganoderma sp. mycelium after 14 days incubation. In this study, the average value of the growth of Ganoderma sp. on PDA medium (7.09 mm day-1) was significantly differs to the growth of Ganoderma sp. on MEA medium (5.41 mm day-1). Besides of that, the fastest growth of Trichoderma spp. was shown by T. pseudokoningii such as 38.14 mm day-1 and significantly differs to T. viride, 27.71 mm day-1 and T. harzianum, 26.31 mm day-1. Based on antagonistic test, T. harzianum exhibited the best inhibition to Ganoderma sp. on PDA medium up to 74.19% and significantly differ to T. pseudokoningii 59.37% and T. viride 41.36%. Similarly on MEA medium treatment T. harzianum exhibited the best inhibition to Ganoderma sp. up to 73.00% and significantly differ to T. pseudokoningii 60.22% and T. viride 51.58%. The inhibition growth of Ganoderma sp. on sengon timber substrate at greenhouse showed that after 1 week, there was a decreasing growth of Ganoderma sp. mycelium when the sengon timber was submerged (Xt1) and obtained the highest value of inhibition up to 1.12 cm on sterile soil treatment + T. harzianum, whilst on sterile soil treatment without T. harzianum, there was an increasing growth of Ganoderma sp. mycelium up to 0.67 cm. Likewise, after 2 weeks of sengon timber submersion (Xt2) on sterile soil treatment + T. harzianum there was a decreasing growth of Ganoderma’s mycelium up to 2.41 cm, whereas on sterile soil treatment without T. harzianum, there was an increasing growth of Ganoderma sp. mycelium up to 1.22 cm.
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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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