Judul: Hama dan penyakit tanaman terung (Solanum melongena L.) di Kecamatan Rancabungur, Kabupaten Bogor
Abstrak: Eggplant (Solanum melongena L.) is a vegetable crop that quite common cultivated in Indonesia. The consumption level of eggplant increases from year to year. There are few information on pests and diseases of the crop in Indonesia. However, pests and diseases become potentially problem in the future when the crop is grown widely. The objective of this research was to obtain information about pest and disease occurrences found in eggplant growing area in Rancabungur their population or damage level. The research method included observation, sampling of the pests and diseases at two eggplant areas, and laboratory identification of the causal agents. The eggplant vegetative and generative growth phases were observed in the same area and period of time. There are some pests found predominantly in eggplant at high population i.e. Empoasca sp. (Hemiptera: Cicadellidae) and Epilachna sp. (Coleoptera: Coccinellidae), whereas Valanga sp. (Orthophtera: Acrididae) (low population), Acherontia sp. (Lepidoptera: Sphingidae), Bactrocera spp. (Diptera: Tephritidae), Mictis longicornis (Hemiptera: Coreidae), and Aulacophora sp. (Coleoptera: Chrysomelidae) were at low population. Eggplant’s diseases found at high incidence in the area were fruit rot (Phomopsis sp.) and anthracnose (Colletotrichum sp.), whereas leaf spot (Alternaria sp.) and bacterial wilt (Ralstonia solanacearum) were at low incidence. All of those pests and diseases, except Bactrocera spp., caterpillar, fruit rot, and anthracnose found at both growth phase of the plant. Fruit rot, and anthracnose were the most important diseases of eggplant at generative phase with the intensity about 47.09% and 40.84%.
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Judul: Penyakit Busuk Buah Pada Terong Di Kecamatan Rancabungur dan Kemang Kabupaten Bogor
Abstrak: Eggplant is one of the most wanted vegetables in Indonesia, even the world. It contains antioxidants which can be used to prevent periodontic disease. It also contains vitamin A and B, and it is good to be consumed by diabetics. Among many diseases in eggplant, fruit rot is one of the major factors as a limited factor in production of this crop. The objective of this study was to observe fruit rot disease condition in subdistricts Rancabungur and Kemang, the district of Bogor. The fruit rot pathogens identified as Phomopsis vexans and Colletotrichum melongenae were covered in all observation plots. Besides of fruit, these pathogens also caused the symptom on stems and/or branches. In one symptomized plant part, these two pathogens were able to appear singly or mixed with the other. In the dry season the symptom was only detected on fruit, while in the wet season can also occurred on stems and/or branches. The disease incidence on fruit during dry season was less than 5% and in the early wet season it increased up to 8%. In wet season observation, disease severity of each plant was varied and mostly higher in the mature plants. Single observation of 20 samples on diseased branches and stems, C. melongenae dominated (80%) as the causal agent.
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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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