Judul: Keefektifan Trichoderma harzianum dan Media Pupuk Kandang dalam Mengendalikan Busuk Pangkal Batang Fusarium oxysporum Tanaman Bawang Daun
Abstrak: Stem rot disease (Fusarium oxysporum) is an important disease of welsh onion. T. harzianum can suppress this disease (F. oxysporum) effectively. Manure contains rich of organic compounds which can increase antagonistic activity of T. harzianum and can induce plant resistance. This study is to evaluate potential uses of T. harzianum and manure formulation to suppress the growth of F. oxysporum. Factor of this study are combination of T. harzianum with chick manure (PAT), T. harzianum with cow manure (PST), T. harzianum with sheep manure (PDT), T. harzianum with rabbit manure (PKT), T. harzianum (T), fungicide (F), control (K), on yield using a complete block randomized design with five replications. In addition, this study also done in vitro test between T. harzianum with F. oxysporum, in laboratory using a complete rondomized design with three replication and isolation microbe from manure. In vitro test have shown that T. harzianum can suppressed F. oxysporum about 74.36%. Eficacy test have shown that addition chick, sheep, cow, and rabbit manure with T. harzianum not effective to controlling stem rot disease by F. oxysporum. Microbe population in chick manure has found hightly than other manure. Fungi in sheep manure more have variation than other manure.
Keyword: Bogor Agricultural University (IPB), welsh onion., T. harzianum, manure, F. oxysporum

Judul: Pemanfaatan cendawan endofit dalam pengendalian busuk umbi (Fusarium oxysporum) pada bawang merah (Allium cepa var. aggregatum)
Abstrak: Yellow disease caused by Fusarium oxysporum is an important disease on shallot which may cause 50% yield loss. The ability to spread rapidly and to survive longer in a suitable soil condition are two main factors causing its difficult to control. Many report on potential of endophytic fungi as biological control agents has been published. The aim of this research was to study the ability of endophytic fungi to suppress the development of yellow disease. The pathogenicity test of endophytic fungi isolates to shallot seeds was carried out in the laboratory and grouped them into pathogenic (growth percentage of 0%-95%), potential pathogenic (95%-99%), and nonpathogenic (100%) isolates. The effectiveness of chosen isolates (PUP1 (70%), HAP2, AAP1, MAT7 (97%) and HAP1, AAP2, AAT, PAP4, PAT3 (100%)) was evaluated in greenhouse by dipping the germinated seeds in a suspension of each isolate and inoculating the testing plant with pathogenic F. oxysporum when it was 14 days old. The effectiveness test in greenhouse showed that all treatments of endophytic fungi had an ability to suppress the development of yellow disease, significantly different to control. The percentage of highest disease incidence was shown by MAT7 isolate (38.75%) with lowest efficacy rate (34.04%) whilst the lowest disease incidence showed by PAP4 (22.50%) and PUP1 (21.25%) isolates with the highest efficacy rate (61.70% and 63.83% respectively).
Keyword: Bogor Agricultural University (IPB), yellow disease, Fusarium oxysporum, endophytic fungi, biological control, antagonism

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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