Judul: Biology and host range of gall fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae) as a biological control agent of siam weed
Abstrak: Gall fly, Cecidochares connexa (Macquart) (Diptera: Tephritidae) is an important natural enemy of siam weed Chromolaena odorata (L.) King & Robinson (Asteraceae), that was introduced to Indonesia from Colombia in 1993. After being release in 1995, the biological aspects of the fly have not been evaluated yet. This research was conducted to study: 1) the biology of C. connexa in the field, 2) the development and number of larval instars, and 3) the host range of the gall fly. Biological parameters observed were larval development, life cycle, longevity of adults and fecundity of the females. Larval instars were determined by observing morphological characters of mandible, sclerite hypopharyng and larval size (volume). The fly host range was evaluated by observing fly infestation and oviposition, larval development and survival, as well as gall formation on three different plant species that were closely related to siam weed (Asteraceae). Results of the study indicated that the eggs were laid in clusters in tissue of terminal or axillary bud. After hatching, larvae bored deeper into the bud and lived inside the gall that was formed on the infested bud until pupation. Gall were visible about two week after oviposition. One gall contained 1 to 13 larvae. There was no correlation between the gall size and number of larvae living in the gall. The gall fly pupate inside the gall. The adults emerged from the pupae and leaved the gall through out gall windows that were prepared and made by the last instar larvae before pupation. The life cycle of the gall fly was completed in 56-77 days. In the study was found that the highest mortality occurred when the fly was in the larval stage, and the natural enemies, especially predators, were the most important mortality factors. Longevity of the fly was about 8-17 days and 7-11 days for female and male, respectively. The fecundity of the fly was 140-329 eggs/female. Based on the size of the mandible and sclerite hypopharyng, there was indication that C. connexa larva had four instars to complete its development. The characters of mandible and hypopharyng were good indicators to determine larval development stage of C. connexa, but not the larval volume. Mandible character was found to be the best indicator to determine the development stage of C. connexa. The shape and size of mandible was different among different instars of C. connexa larvae. Form the host range test, it was known that C. connexa laid eggs on all species of tested plants. However, larvae could survive on the tested plants for no longer than two weeks. On babadotan, the fly infestations were able to stimulate gall formation but the larvae were fail to complete their development. It can be concluded that C. connexa is a host specific species that can develop and complete its life cycle only on siam weed.
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Judul: Implikasi eksistensi chromolaena odorata (l.) King & robinson (asteraceae) dan agens hayatinya cecidochares connexa macquart (diptera: tephritidae) terhadap struktur komunitas serangga dan tumbuhan lokal
Abstrak: ALAL HUDA JAYA. S. Implication of existence both of Chromolaena odorata (L.) King & Robinson (Asteraceae) and its biological control agent - Cecidochares connexa Macquart (Diptera: Tephritidae) to local plant and insect community structure. Supervisors: DAMAYANTI BUCHORI and SOEKISMAN TJITROSEMITO. The aims of this research were (1) to study density and population distribution of C. odorata and its biological control agent - C. connexa, and (2) to study local plant and insect community structure in invaded area of C. odorata. Several activities have been conducted i.e. survey of research sites, vegetation analysis, and insect sampling. The study sites were selected base on purposive sampling method. All area located in Bogor district (Parung Panjang, Setu, Darmaga, Gunung Bunder, Ciawi, and Cisarua), Sukabumi district (Gunung Salak, Gunung Halimun, and Pakuwon), and Cianjur district. Analysis of vegetation were conducted using combination of transect and quadrate method. Insect were sampled by setting up several traps inside the plots. Pitfall trap and yellow pan trap were set up inside the plot, whereas malaise trap were placed between two transect lines. The result found that invasive exotic plant species (C. odorata) spread on whole study sites and well-growth on different habitat types (plantations, production forest, low land, and high land). Their population densities tend to decrease with increasing altitude. The occurrences of C. odorata co-exist with its biological control, the gall flies C. connexa. Almost all study sites (except Gunung Halimun and Cianjur) found these flies. Recently, C. connexa have established and wide spread, although the present of barrier (like mountain) is restriction factor for distribution of flies in West Java. Over 131.132 individual of plants consist of 21 families and 44 species were identified co-exist with C. odorata in Bogor area (Parung Panjang, Setu, Darmaga, and Gunung Bunder). In the same area, over 24.213 individual of insect consist of 14 orders, 132 families, and 568 species were found in C. odorata habitat. Three dominance insect orders i.e. Hymenoptera, Diptera, and Hemiptera were collected with high species richness and abundance. Implication of existence of C. odorata caused replacement local plant species and homogenization habitat on spatial scale. Introduction of C. odorata and its biological control agent caused and consequently associate with local insects.
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Judul: Sintesis BaTiO3 dari Campuran Ba(OH)2 dan TiO2 dengan Tambahan PbO
Abstrak: Piezoelectric material can generate electric field in response to applied mechanical stress. Conversely, they can stretch and contract in response to an electric field. This material can be used for many applications such as transducer, microphone, ultrasound, and pressure gauge. Barium titanate is a ferroelectric material with piezoelectric properties that can be synthesized easily. The aim of this study is to synthesis barium titanate from mixture of Ba(OH)2 and TiO2, also observe its optimum temperature and the effect of PbO addition. The method of synthesis was solid-state reaction and sol-gel method, then the products were characterized with x-ray diffraction (XRD). Based on XRD analysis, the optimum temperature for both methods was 800°C. Addition of PbO to BaTiO3 in the solid-state reaction formed a compound with formula of Ba1-xPbxTiO3. The addition has changed diffraction pattern peak at 2θ and strengthened its tetragonal structure. The best result was obtained at x of 0.5 which will form a compound of Ba0.5Pb0.5TiO3.
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