Judul: Inventory Disease on Acacia crassicarpa Cunn Ex Benth at Kerinci Central Nursery 1 and Pelalawan Estate PT RAPP Pelalawan District Riau
Abstrak: Acacia crassicarpa merupakan salah satu tanaman berkayu yang digunakan untuk pembuatan pulp dan kertas. Hutan tanaman industri (HTI) PT. Riau Andalan Pulp and Paper (RAPP) merupakan salah satu HTI yang membudidayakan tanaman A. crassicarpa. A. crassicarpa dibudidayakan secara monokoltur dan tumbuh baik meskipun di lahan kritis. Penyakit tanaman merupakan salah satu masalah penting di perkebunan Akasia. Infeksi patogen dapat menyebabkan gangguan fisiologis yang mempengaruhi pertumbuhan tanaman dan kualitas kayu. Penelitian ini bertujuan untuk mengamati dan mengidentifikasi patogen yang menginfeksi A. crassicarpa di PT. RAPP. Pengamatan penyakit dilakukan di empat lahan selama 4 bulan, dimulai dari Januari sampai Mei 2022 di Kebun Pelalawan dan Sentral Pembibitan 1 PT RAPP Pangkalan Kerinci, Kabupaten Pelalawan, Provinsi Riau. Pengambilan sampel menggunakan metode purposive sampling. Tahap identifikasi penyakit dilakukan di laboratorium PT RAPP. Patogen penyebab diidentifikasi berdasarkan gejala visual dan bentuk mikroskopisnya. Penyakit bibit A. crassicarpa adalah layu daun yang disebabkan oleh Rhizoctonia sp., sedangkan penyakit pada tanaman adalah bercak daun yang disebabkan oleh Pestalotiopsis sp. dan Passalora perplexa, serta hawar daun yang disebabkan oleh Xanthomonas campestris pv. acaciae. Faktor yang mempengaruhi infeksi patogen di lapangan antara lain curah hujan, suhu, dan kelembaban., Acacia crassicarpa is a woody plant used for pulp and paper production. Industrial plantation forest (HTI) PT. Riau Andalan Pulp and Paper (RAPP) is one of the HTI plantations that cultivates A. crassicarpa plants. A. crassicarpa is cultivated in monoculture and grows well even on critical land. Plant disease is one of the important problems in Acacia plantations. Pathogenic infections can cause physiological disturbances that affect plant growth and wood quality. This study aims to observe and identify the pathogens that infect A. crassicarpa in PT. RAPP. Disease observations were carried out in four fields for 4 months, starting from January to May 2022 at the Pelalawan Garden and Central Nursery 1 PT RAPP Pangkalan Kerinci, Pelalawan Regency, Riau Province. Sampling using purposive sampling method. The disease identification proses was conducted at PT RAPP laboratory. The causative pathogen is identified based on its visual symptoms and microscopic appearance. Seedling disease of A. crassicarpa is leaf wilt caused by Rhizoctonia sp., while plant diseases were leaf spot caused by Pestalotiopsis sp. and Passalora perplexa, and leaf blight caused by Xanthomonas campestris pv. acaciae. Factors that affect disease infections in the field include rainfall, temperature, and humidity.
Keyword: Acacia crassicarpa, hutan tanaman industri, patogen, penyakit

Judul: Coleoptera that Associated with Acacia (Acacia crassicarpa) and Implementation of Integrated Pest Management in PT RAPP, Pelalawan, Riau
Abstrak: Pohon Acacia crassicarpa umumnya digunakan sebagai bahan utama pembuatan pulp dan kertas. Salah satu hama yang menyerang pohon A. crassicarpa ialah kumbang Coleoptera. Selain sebagai hama, beberapa jenis kumbang juga berperan sebagai musuh alami yang berpotensi untuk menekan populasi hama lainnya serta mendukung penerapan pengendalian hama terpadu (PHT). Pengendalian hama terpadu dilakukan sebagai koreksi terhadap kebijakan pengendalian hama yang mengutamakan penggunaan pestisida. PHT dilakukan dengan mengkombinasikan beberapa metode pengendalian yang salah satunya ialah pemanfaatan musuh alami. Tujuan magang ini mengetahui kumbang yang berasosiasi dengan A. crassicarpa dan penerapan pengendalian hama terpadu di PT RAPP, Pelalawan, Riau. Kegiatan magang dilakukan dengan praktek langsung dengan mengikuti arahan pembimbing magang, mengikuti aktivitas di Laboratorium Entomologi, wawancara dan pengamatan mandiri dengan mengoleksi kumbang dari enam kompartemen hutan A. crassicarpa yang berumur 3-7 bulan untuk dilakukan evaluasi dan identifikasi menggunakan awetan serangga di laboratorium dan buku Borror et al. 1996 sebagai acuan. Kumbang yang berpotensi sebagai hama ialah Rhytiphora sp. dan Alaus sp., sedangkan kumbang yang berperan sebagai musuh alami ialah Coelophora sp dan Halmus sp. Beberapa pengendalian hama secara terpadu dilakukan di PT RAPP seperti pemanfaatan parasitoid telur Trichogamma sp., green lace wing, Sycanus sp. Eocanthecona sp., kumbang Menonchilus sp., dan feromon seks Helopeltis sp., Acacia crassicarpa is a tree species commonly used as the main ingredient for pulp and paper. Among the pests that attack A. crassicarpa tree are the insect belong to the order of Coleoptera (beetles). Apart from being pests, some beetles are known as natural enemies of others insects, that have potential to suppress pest populations and to support the implementation of integrated pest management (IPM). Integrated pest management is carried out as a correction to pest control policies that prioritize the use of pesticides. IPM is done by combining several control methods that one of them is the use of natural enemies. The purpose of this internship was to identify beetles which have association with A. crassicarpa and to know the application of integrated pest management in Industrial Forest Plantation at PT RAPP, Riau. The internship was carried out by following the guidance of the supervisor to do direct practices, participating in activities in the Entomology Laboratory, doing interviews and doing independent observations, and collections of beetles from six compartments of 3-7 month-old A. crassicarpa forest for evaluation and identification in the laboratory. Beetles that have potential to be pests of A. crassicarpa were Rhytiphora sp. and Alaus sp., while the beetles that act as natural enemies were Coelophora sp and Halmus sp.. Some integrated pest control practices have been implemented at PT RAPP, such as the use of egg parasitoid, Trichogamma sp, the use of predator (Neuroptera green lace wing, Sycanus sp. Eocanthecona sp., Menonchilus sp.), and the use of sex pheromones of Helopeltis sp..
Keyword: Acacia crassicarpa, beetles, natural enemies, pests, pulp, paper

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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