Judul: Percobaan pemasangan feromon seks kumbang penggerek ubi jalar. Cylas formicarius. (Coleoptera : Curculionidae)
Abstrak: Penelitian ini dilaksanakan di lahan petani Desa Cibatok II, Kecamatan Cibungbulang, Kabupaten Bogor, Propinsi Jawa Barat. Pertanaman ubi jalar seluas 1 ha dibagi menjadi 20 petak. Perangkap berferomon diletakkan pada setiap petak yang dipilih secara acak dari 20 petak tersebut. Jumlah perangkap yang digunakan adalah 5 buah. Percobaan pemasangan feromon seks terbagi atas uji pendahuluan yang dilaksanakan pada tanggal 4 - 9 Desember 1989, dan uji lanjutan yang dilaksanakan pada tanggal 17 20 - Januari 1990. Pengamatan jumlah C. formicarius jantan yang tertangkap dilakukan setiap hari pada uji pendahuluan, sedang pada uji lanjutan pengamatan dilakukan setiap 2 jam pada waktu siang hari dan 12 jam pada waktu malam hari. Selama uji pendahuluan, jumlah kumbang jantan yang tertangkap selama 6 hari adalah 1771.2 ekor/perangkap. Pada uji lanjutan, jumlah kumbang yang tertangkap selama 4 hari rata-rata 204.75 ekor/perangkap pada malam hari, dan siang hari rata-rata 39.10 ekor/perangkap. Jumlah kumbang jantan yang tertangkap berbeda nyata antara malam hari dengan siang hari, begitu juga berbeda nyata antara pagi hari (06.00-12.00) dengan siang/sore hari (12.00-18.00). Feromon seks yang dikembangkan oleh AVRDC bekerja dengan baik yang dapat digunakan untuk monitoring dan dapat disarankan untuk mengendalikan Cylas formicarius.
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Judul: Perilaku Kawin Kumbang Cylas formicarius (Fabr.) terhadap Feromon Seks Sintetik pada Tanaman Ubi Jalar
Abstrak: Cylas formicarius (Fabr.) is weevil that infest sweet potato. Female C. formicarius release sex pheromone to attracted the male for mating. Synthetic pheromone of female C. formicarius is determined as (Z)-3-dodecen-1-ol(E)-2-butenoat. This research were aimed to explore several aspects of male C. formicarius behaviour such as (1) attraction to several concentrations of synthetic pheromone (2) flight response to pheromone trap in several height trap position and, (3) time response within 24 hours to sex pheromone trap. This research was conducted from Januari-Mei 2013. Behavioural test of male C. formicarius were carried out using pheromone water trap method and observation mating behaviour of C. formicarius were recorded using handycam. The highest number of weevil collected was trap by 250-1000 μg/rubber septa. The optimum of flight response was at 25-50 cm from ground level. The peak of C. formicarius to response synthetic pheromone between 18.00–20.00 and mating activity of C. formicarius observed at 18.29. This mating behaviour information can be used to control its population.
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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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