Judul: Identification of Aroid Plant Diseases (Araceae) and The Effect of Biological Agents on The Growth Alocasia macrorrhiza variegate
Abstrak: Tanaman aroid merupakan tanaman dari famili Araceae dan termasuk tanaman hortikultura yang bernilai ekonomis tinggi. Pada tahun 2021 Kementerian Pertanian melaporkan nilai ekspor tanaman hias aroid seperti Alocasia mencapai 16,9 ribu batang dengan perkiraan nilai ekonomi Rp 1,6 miliar. Penelitian ini bertujuan mengetahui informasi penyakit pada tanaman aroid serta pengaruh aplikasi agens hayati terhadap pertumbuhan tanaman Alocasia macrorrhiza variegate. Penelitian dilaksanakan pada bulan Februari sampai Juli 2022. Pengamatan penyakit dilakukan dengan mengamati tanaman pada rak populasi tanpa tanaman pinggir dan menghitung kejadian penyakit dan kerusakan penyakit. Deteksi dan identifikasi penyakit di laboratorium diperoleh 6 patogen dari kelompok cendawan. Patogen yang ditemukan adalah Colletotrichum sp. (antraknosa daun), Bipolaris sp., Helminthosporium sp., dan Cercospora sp. (bercak daun), Fusarium sp. (hawar daun), dan Puccinia sp. (karat daun). Pengaruh agens hayati terhadap pertumbuhan tanaman Alocasia macrorrhiza variegate dilakukan dengan 5 perlakuan, 3 ulangan, dan 10 tanaman per perlakuan. Hasil terbaik adalah perlakuan A3 (Trichoderma 30 g) pada setiap indikator dan perlakuan terendah pada A0 (Kontrol)., Aroid plants are plants of the Araceae family and include horticultural plants with high economic value. In 2021 The Ministry of Agriculture reported that the export value of aroid ornamental plants such as Alocasia reached 16.9 thousand stems with an estimated economic value of Rp 1,6 billion. This study aims to determine information diseases in aroid plants and the effect of application the biological agents on plant growth of Alocasia macrorrhiza variegate. The study was conducted from February to July 2022. Disease observation was carried out by observing plants on population shelves without edge crops and calculating the incidence of disease and disease damage. Detection and identification of disease in the laboratory obtained 6 pathogens of the fungus group. The pathogen found was Colletotrichum sp. (leaf anthracnose), Bipolaris sp., Helminthosporium sp., and Cercospora sp. (leaf spot), Fusarium sp. (leaf blight), and Puccinia sp. (leaf rust). The effect of biological agents on growth in Alocasia macrorrhiza variegate plants was carried out with 5 treatments, 3 replications, and 10 plants per treatment. The best result was A3 treatment (Trichoderma 30 g) on each observation indicator and the lowest yield was in treatment A0 (Control).
Keyword: Aroid plants, diseases, biological agents

Judul: Major Pests and Diseases of Orchid (Dendrobium sp.) in Nugroho Orchid Garden, South Tangerang City, Banten Province
Abstrak: Anggrek (Dendrobium sp.) merupakan salah satu komoditas tanaman hias yang banyak dibudidayakan dan bernilai ekonomi tinggi. Serangan hama dan penyakit merupakan salah satu kendala yang dihadapi dalam proses budidaya anggrek dendrobium. Penelitian bertujuan mengamati, menentukan intensitas serangan dan mengidentifikasi hama dan penyakit tanaman anggrek di Kebun Anggrek Nugroho, Tangerang Selatan. Pengamatan hama dan penyakit dilakukan setiap minggu selama dua bulan pada lima varietas anggrek yaitu Sakda Beauty, Liberty White, Ckaii Waiane, Airway Blue, dan Sminn Red. Informasi terkait budi daya digali melalui wawancara dengan pengelola kebun. Identifikasi hama dan penyakit dilakukan dengan membandingkan gejala yang teramati di lapangan dengan referensi dari literatur. Hama utama yang ditemukan pada pertanaman ialah tungau pipih merah anggrek (Tenuipalpus sp.), sedangkan untuk penyakit utama adalah bercak daun cercospora oleh Cercospora sp, dan penyakit mosaik oleh Cymbidium mosaic virus. Insidensi serangan tungau pipih merah berkisar 0-100%, penyakit mosaik berkisar antara 0-80%, dan bercak daun cercospora berkisar antara 0-72%. Intensitas keparahan tungau pipih merah berkisar antara 0-60%. Skor keparahan mosaik berkisar antara 0-1,32, sedangkan untuk bercak daun cercospora berkisar antara 0-1,56. Faktor yang memengaruhi intensitas hama dan penyakit adalah frekuensi penyiraman yang tinggi, frekuensi dan dosis pemumpukan yang tinggi, serta pencampuran dua jenis insektisida dengan cara kerja yang sama. Hama lain yang ditemukan di kebun adalah kutu tempurung, sedangkan penyakit lain ditemukan bercak daun phyllosticta, antraknosa, dan busuk lunak dengan insidensi cukup rendah. Rekomendasi pengelolaan yang dianjurkan untuk Kebun Anggrek Nugroho adalah pemberian dosis pupuk, frekuensi penyiraman, dan penggunaan insektisida yang sesuai, serta penggunaan pestisida hayati yang ramah lingkungan., Orchid (Dendrobium sp.) is one of the ornamental plants which are widely cultivated and have high economic value. Pests and diseases are one of the constraints on Dendrobium sp. cultivation. The study aimed to observe, determine the intensity and identify the insect pests and pathogens of orchid plants in the Nugroho Orchid Garden, South Tangerang. The pests and pathogens observations were carried out every week regularly for two months on five orchid varieties, i.e. Sakda Beauty, Liberty White, Ckaii Waiane, Airway Blue, and Sminn Red. The cultivation data was collected by interviewing the garden’s manager. Identification of pests and diseases was conducted by comparing the visual symptoms found in the garden with the appropriate literature references. The major pest of Dendrobium sp. is red flat mites (Tenuipalpus sp), while the major disease is cercospora leaf spot caused by Cercospora sp. and mosaic caused by Cymbidium mosaic virus. The incidence of red flat mites ranges from 0-100%, with the intensity ranging from 0- 60%, while the incidence of CymMV ranges from 0-80%, and cercospora leaf spot range from 0-72%, depending on the varieties. The severity score of the mosaic diseases ranged from 0-1.32, and the cercospora leaf spot ranged from 0-1.56. The soft scales, phyllosticta leaf spot, anthracnose, and soft rot also found with low incidence. The factors that affect pest and disease intensity, such as high frequency of watering, overdose application of fertilizer, and mixture application of pesticide with similar mode of action. The recommendation for appropriate management of pests and diseases at Nugroho Orchids’ Garden is water, fertilizer, and
Keyword: cultivation, control, dendrobium, leaf spot, mite, virus

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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