Judul: Endosymbionts Associated with Banana Aphid Pentalonia nigronervosa (Hemiptera: Aphididae)
Abstrak: Banana bunchy top disease caused by Banana bunchy top virus (BBTV), is one of the constraints to banana production worldwide, including in Indonesia. BBTV is transmitted by aphid Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae) in a persistent manner. Several factors affecting the efficiency of insect vector in transmitting the virus are temperature, developmental stage of insect vector, and their association with endosymbionts. The objective of this study is to identify and analyze the genetic diversity of endosymbionts associated with banana aphid P. nigronervosa. Aphid samples were collected around Bogor from banana plants that showed symptoms of BBTV infection and those that looked healthy. Identification of endosymbionts was carried out by polymerase chain reaction (PCR) method using specific primers for nine endosymbionts, namely Buchnera aphidicola, Rickettsia, Wolbachia, Rickettsiella, Serratia symbiotica, Regiella insecticola, Hamiltonella defensa, Arsenophonus sp., Spiroplasma. Confirmation of BBTV infection in plant samples and identification of banana aphid were also carried out by PCR, using BBTV specific primers and mtCOI universal primers, respectively. BBTV infection was confirmed in symptomatic sample plants. Banana aphids collected were identified as P. nigronervosa with 89%-100% homology to accessions in Genbank. Primary endosymbionts (B. aphidicola) were successfully amplified from all aphid samples, while secondary endosymbionts (Rickettsia, Wolbachia, Rickettsiella, Spiroplasma, Arsenophonus, and S. symbiotica) were only successfully amplified from some aphid samples. Endosymbiont diversity was found to be higher in aphids from healthy plants. The relationship between endosymbionts, aphids, and banana bunchy top disease incidence needs further study., Penyakit kerdil pisang yang disebabkan oleh Banana bunchy top virus (BBTV) merupakan salah satu kendala produksi pisang di seluruh dunia, termasuk Indonesia. BBTV ditularkan melalui serangga vektor kutudaun Pentalonia nigronervosa Coquerel (Hemiptera: Aphididae) secara persisten. Beberapa faktor yang memengaruhi efisiensi serangga vektor menularkan virus adalah suhu udara, tahap perkembangan serangga vektor, dan asosiasinya dengan endosimbion. Penelitian dilakukan dengan tujuan mengidentifikasi dan menganalisis keragaman genetik endosimbion dari kutudaun pisang P. nigronervosa. Pengambilan sampel kutudaun dilakukan di sekitar Bogor pada tanaman pisang yang menunjukkan gejala infeksi BBTV maupun yang tampak sehat, masing-masing sebanyak lima tanaman. Identifikasi endosimbion dilakukan dengan metode polymerase chain reaction (PCR) menggunakan primer spesifik sembilan endosimbion, yaitu Buchnera aphidicola, Rickettsia, Wolbachia, Rickettsiella, Serratia symbiotica, Regiella insecticola, Hamiltonella defensa, Arsenophonus sp., Spiroplasma. Konfirmasi infeksi BBTV pada tanaman contoh dan identitas kutudaun juga dilakukan dengan metode PCR, berturut-turut menggunakan primer spesifik BBTV dan primer universal mtCOI. Infeksi BBTV berhasil terkonfirmasi pada tanaman contoh yang menunjukkan gejala. Demikian pula kutudaun pisang yang dikumpulkan berhasil diidentifikasi sebagai P. nigronervosa dengan homologi 89%-100% terhadap aksesi pada Genbank. Endosimbion primer (B. aphidicola) berhasil diamplifikasi dari semua sampel kutudaun; sedangkan endosimbion sekunder (Rickettsia, Wolbachia, Rickettsiella, Spiroplasma, Arsenophonus, S. symbiotica) hanya berhasil diamplifikasi dari beberapa sampel kutudaun. Keragaman endosimbion lebih banyak ditemukan pada kutudaun yang berasal dari tanaman sehat. Hubungan antara endosimbion, kutudaun dan insidensi penyakit kerdil pisang perlu dipelajari lebih lanjut.
Keyword: Banana bunchy top virus, insect vector, polymerase chain reaction, primary endosymbiont, secondary endosymbiont

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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