Judul: Variasi Sekuens DNA mtCOI Kutudaun (Hemiptera: Aphididae) pada Beberapa Varietas Tanaman Pisang.
Abstrak: Kutudaun yang umumnya ditemukan pada tanaman pisang adalah Pentalonia nigronervosa Coquerel dan P. caladii van Der Goot (Hemiptera: Aphididae). P. nigronervosa dikenal menjadi vektor penyakit kerdil pisang yang disebabkan oleh Banana Bunchy Top Virus (BBTV), sedangkan P. caladii belum diketahui dengan pasti perannya sebagai vektor BBTV. P. nigronervosa dan P. caladii adalah spesies kriptik, yang dulunya digolongkan dalam satu spesies yang sama dengan forma yang berbeda. Penelitian ini bertujuan mengetahui jenis dan mempelajari variasi karakter molekuler kutudaun yang ditemukan pada beberapa varietas pisang berdasarkan sekuens DNA mtCOI. Pengambilan sampel kutudaun dilakukan di beberapa wilayah di Bogor dan Sukabumi. Hasil identifikasi didapatkan dua spesies kutudaun pada tanaman pisang yaitu P. nigronervosa dan P. caladii. Panjang sekuens DNA mtCOI dari P. nigronervosa dan P. caladii adalah 717–721 pb. Sekuens fragmen DNA mtCOI didapatkan 698 pb conserved. Komposisi basa Adenin dan Timin (A+T) pada semua sampel berkisar 72.41–73.71%. Pada sekuens homologi DNA mtCOI, P. nigronervosa yang berasal dari Bogor dan Sukabumi memiliki nilai homologi berkisar 98.9–99.8% dengan P. nigronervosa Kanada (GU140277.1) dan P. nigronervosa India (JN160719.1). Sekuens DNA mtCOI P. caladii memiliki nilai homologi berkisar 96.0–99.8% dengan P. nigronervosa f. caladii Kanada (GU140254.1) dan P. nigronervosa f. caladii India (KP076373.1). Hasil penelitian ini menunjukkan bahwa jenis varietas pisang tidak menyebabkan perbedaan sekuens DNA mtCOI P. nigronervosa dan karakter molekuler berdasarkan sekuens DNA mtCOI mendukung hasil identifikasi secara morfologi berdasarkan Ultimate Rostral Segment (URS) dalam membedakan dua spesies kriptik kutudaun, P. nigronervosa dan P. caladii.
Keyword: amplifikasi DNA, aphids, penyakit kerdil, vektor virus

Judul: Identifikasi Kutudaun asal Tanaman Pisang dan Pengaruh Banana bunchy top virus terhadap Siklus Hidup dan Fekunditas Kutudaun
Abstrak: Banana bunchy top disease (BBTD) stands out as a significant threat to banana plants in Indonesia, capable of causing a complete yield loss of up to 100%. Pentalonia nigronervosa and Pentalonia caladii (Hemiptera: Aphididae) have been identified as vectors persistently transmitting the Banana bunchy top virus (BBTV). Previous studies have documented the infestation of these aphid species on banana plants in the provinces of West Java, East Java, and Central Java. Consequently, there was a need for a comprehensive survey to assess the prevalence of aphids on banana plants throughout Indonesia, followed by the identification of aphid species. Beyond transmitting viruses from one plant to another, intricate interactions exist between aphids and the viruses they carry, manifesting in a shorter life cycle for vector insects and heightened fecundity. These dynamics enhance the potential of vectors to disseminate BBTV. This research aimed (1) to identify aphid species on banana plants using eleven morphometric characters and the sequence of partial mtCO-I gene and (2) to determine the effect of BBTV-infected plants on the life cycle and fecundity of aphids. The research activities were conducted in two phases. The first phase involved morphometric and molecular identification of aphids from July to December 2022. The second phase, focusing on the effects of BBTV-infected plants on the life cycle and fecundity of aphids, was executed from January to May 2023. The study was conducted at the Insect Biosystematics Laboratory, Plant Virology Laboratory, Cikabayan Greenhouse, Department of Plant Protection, Faculty of Agriculture, Bogor Agricultural University. Aphid samples were collected from several banana cultivars including Mas, Ketip, Muli, Cavendish, Ambon, Kepok, Randah, Pinang, Awak, and the wild banana, Musa acuminata from four provinces in Indonesia, namely Bali, West Kalimantan, North Kalimantan, and East Kalimantan. Morphological and morphometric identification of aphids using the permanent slide preparation method from Blackman and Eastop (2000). Identification of aphids was pursued up to the species level. Eleven morphometric characters were measured: length of body, head width, antennal length, length of antennal segment I-II, length of antennal segment III-V, length of antennal segment VI, length of ultimate rostrum segment, length of siphunculus, length of femur, length of tibia and length of caudal. Molecular identification begins with the DNA extraction process for total aphids followed by the method proposed by Goodwin et al. (1994) with modifications in the final stage, involving resuspension with a 10 μl solution of ddH2O. The obtained total DNA from aphids served as a template for the mtCO-I gene amplification stage, employing universal primers LCO1490 (5'-GGTCAACAAATCATAAAGAATT-GG-3') and HCO2198 (5'-TAAACTTCAG GGTGACCAAAAAATCA-3') as forward and reverse primers, respectively, with an amplicon target measuring 710 bp. The amplification of the target DNA underwent denaturation, annealing (primary attachment), and elongation (synthesis of new DNA strands) stages. Subsequently, the amplification product was visualized through 1% agarose gel electrophoresis. Successfully amplified samples were then forwarded to a service provider for the sequencing stage. Data related to the measurement of morphometric characters in aphids were tabulated using Microsoft Excel 365, employing t-test and PCA (Principal Component Analysis) for analysis. The molecular data were analyzed using Geneious Prime software, involving
Keyword: morphometric, mtCOI, P. caladii, P. nigronervosa, viruliferous

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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