Judul: Potency of Chitinolytic Bacteria from Lizard Intestines and Nepenthes Plant Fluid as Biocontrol Agents for Aphis craccivora
Abstrak: Bakteri kitinolitik merupakan kelompok bakteri yang dapat menghasilkan enzim kitinase. Enzim kitinase memiliki kemampuan dalam mendegredasi kitin yang merupakan komponen utama dari eksoskeleton atau komponen penyokong dan pelindung luar dari serangga salah satunya adalah kutudaun Aphis craccivora Kutudaun A. craccivora merupakan hama penting pada tanaman Leguminoceae di Indonesia. Serangan kutudaun menyebabkan kerusakan baik secara langsung dan tidak langsung. Hama kutudaun A. craccivora menyebabkan kerugian secara kualitatf dan kuntitatif paling banyak pada tanaman kacang panjang di semua benua. Dalam budi daya tanaman kacang panjang, serangan hama paling banyak menyebabkan penurunan hasil produksi kacang panjang. Hama kutudaun A. craccivora menyebabkan penurunan hasil produksi sebesar 65,78% di Indonesia. Penelitian ini bertujuan mendapatkan isolat bakteri kitinolitik asal usus cicak dan cairan kantong semar yang berpotensi mengendalikan kutudaun yang menyerang tanaman kacang panjang. Tahapan penelitian mencakup isolasi bakteri positif kitinolitik, uji keamanan hayati, uji indeks kitinolitik, uji pengaruh bakteri kitinolitik terhadap mortalitas A. craccivora, serta identifikasi secara morfologi dan molekuler. Hasil penelitian didapatkan 28 isolat bakteri positif kitinolitik (12 asal usus cicak dan 16 asal kantung semar). Hasil uji keamanan hayati (uji hemolisis agar darah dan reaksi hipersensitif didapatkan 7 isolat bakteri (3 dan 4 masing masing dari usus cicak dan kantung semar) yang tidak bersifat patogen terhadap mamalia dan tumbuhan. Ketujuh isolat tersebut memiliki indeks kitinolitik yang berbeda. Pengujian lebih lanjut terhadap mortalitas kutudaun A. craccivora pada berbagai tahap perkembangan kutu daun menunjukkan tingkat mortalitas yang berbeda beda. Perlakuan isolat bakteri kitinolotik dapat menyebabkan mortalitas pada instar 3, 4, dan imago masing masing sebesar 85, 75, dan 95% 72 jam setelah perlakuan. Tujuh isolat yang berpotensi menjadi agens biokontrol yaitu UC102; UC108; UC117; KS8; KS62; KS66; dan KS72. Hasil identifikasi secara morfologi didapat UC102; UC108; UC117; dan KS8 bersifat Gram negatif, isolat KS62; KS66; dan KS72 bersifat Gram positif. Identifikasi secara molekuler didapatkan bahwa isolat KS66 merupakan bakteri genus Pseudomonas aeruginosa., Chitinolytic bacteria are a group of bacteria that can produce the chitinase enzyme. The chitinase enzyme can degrade chitin which is the main component of the exoskeleton or external supporting and protective component of insects, one of which is the Aphis craccivora. The A. craccivora is an important pest of Leguminoceae plants in Indonesia. Aphid attacks causes both direct and indirect damage. The aphid pest A. craccivora causes yield losses to long bean plants on all continents except Antarctica. In long bean cultivation, pests are reported to be the most common attack that causes a decrease in production. A craccivora have been reported to cause yield losses up to 65.78% in long bean production in Indonesia. This study aims to obtain isolates of chitinolytic bacteria from the intestines of lizards and nephentes liquid that have the potential biocontrol A. craccivora. The research steps included isolation of chitinolytic, biosafety, chitinolytic index-test, effectiveness assay of chitinolytic bacteria on A. craccivora, and morphological and molecular identification. The results of the research showed that there were 12 positive chitinolytic bacteria from the lizard intestine from 124 isolates, 16 isolates from 93 isolates from the nephentes plant fluid, resulting in a total of 28 chitinolytic positive bacterial isolates. The results
Keyword: kitin, Pseudomonas aeruginosa, eksoskeleton, indeks kitinolitik, kacang panjang

Judul: Aphis craccivora Koch (Hemiptera: Aphididae) and their control in yardlong bean field
Abstrak: Kacang panjang merupakan tanaman sayuran yang berperan sebagai sumber protein, vitamin, dan mineral. Salah satu hama penting tanaman kacang panjang adalah kutu daun Aphis craccivora. Pengendalian yang umum dilakukan petani terhadap hama ini adalah penggunaan insektisida sintetik. Studi pustaka ini bertujuan memberikan informasi tentang bioekologi kutu daun A. craccivora dan cara pengendaliannya pada pertanaman kacang panjang sebagai dasar penyusunan strategi pengendalian secara terpadu. Pengumpulan data dan informasi dilakukan dengan metode studi pustaka. Tahapan penulisan terdiri dari perumusan masalah, pengumpulan data, analisis, dan simpulan. Berdasarkan studi pustaka, kutu daun mulai ditemukan di pertanaman kacang panjang pada fase bibit, pertumbuhan vegetatif sampai fase generatif. Perkembangan populasinya secara alami dipengaruhi oleh faktor makanan, musuh alami dan faktor lingkungan seperti curah hujan. Pengendalian kutu daun secara terpadu dapat dilakukan dengan budidaya tanaman yang baik, pemanfaatan musuh alami hama, bioinsektisida, insektisida nabati, dan insektisida sintetik sebagai alternatif terakhir. Musuh alami kutu daun antara lain Menochilus sexmaculatus, Ischiodon scutellaris, Aphidius sp., dan Lysiphlebus fabarum. Bioinsektisida Lecanicillium lecanii dan Beauveria bassiana serta insektisida nabati ekstrak daun sirsak, gulma siam, dan daun pepaya berpotensi sebagai sarana pengendalian alternatif yang aman dan ramah lingkungan., Yardlong bean is a vegetable plant that contains high protein, vitamins, and minerals. One of the important pests of the yardlong bean plant is the Aphis craccivora Koch. Farmers often control this pest by using synthetic insecticides. This literature research aims to provide information about the bioecology of A. craccivora and methods to control them in yardlong bean cultivation as the basis for developing an integrated control strategy. Data and information collection were carried out using the literature study method. The writing stages consist of problem formulation, data collection, analysis, and making conclusions. Based on literature studies, aphids appeared to become destructive in yardlong bean plantations on seedling, vegetative growth to generative phase. Aphids population development is often influenced by food factors natural enemies, and environmental factors such as rainfall. Integrated control of aphids can be carried out by good cultivation of plants, utilization of natural enemies of pests, bioinsecticides, botanical insecticides, and synthetic insecticides as a last resort. Natural enemies of aphids include Menochilus sexmaculatus, Ischiodon scutellaris, Aphidius sp., and Lysiphlebus fabarum. Bioinsecticides Lecanicillium lecanii and Beauveria bassiana as well as vegetable insecticides soursop leaf extract, siamese weeds, and papaya leaves have the potential as a means of controlling safe and environmentally friendly alternatives.
Keyword: bioinsecticides, botanical insecticides, sintetic insecticides, natural enemy

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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