Judul: Knowledge, Attitudes, and Actions of Sweet Potato Farmers in the Management of Plant Pest Organisms in Sub-district Cilimus, Kuningan Regency, West Java
Abstrak: Ubi jalar (Ipomoea batatas L.) merupakan salah satu jenis tanaman palawija yang dapat menjadi sumber karbohidrat, sehingga dapat dijadikan sebagai alternatif makanan pokok. Penelitian ini bertujuan mengetahui tingkat pengetahuan, sikap, dan tindakan petani ubi jalar di Kecamatan Cilimus Kabupaten Kuningan dalam upaya pengelolaan Organisme Pengganggu Tanaman (OPT). Penelitian dilakukan dengan menggunakan metode survei langsung di lapangan melalui wawancara dengan petani ubi jalar menggunakan kuesioner terstruktur. Lokasi sampel ditentukan secara terpilih dan penentuan responden dilakukan dengan metode purposive sampling dengan jumlah petani responden sebanyak 60 responden dari empat desa. Hasil penelitian menunjukkan bahwa pestisida masih digunakan dalam mengendalikan OPT. Sebagian besar petani responden telah mengetahui dengan baik praktik budi daya ubi jalar, namun pengetahuan mereka mengenai musuh alami masih terbatas. Mayoritas petani ubi jalar beranggapan bahwa hama boleng dan penyakit layu bakteri merupakan hama penyakit yang sulit dikendalikan. Pengalaman bertani memiliki hubungan yang signifikan dengan sikap petani pada taraf nyata 5% dan 10% dan keikutsertaan dalam program sekolah lapang pengendalian hama terpadu (SLPHT) memiliki hubungan yang signifikan dengan tindakan petani dalam pengelolaan OPT ubi jalar., Sweet potato (Ipomoea batatas L.) is one of secondary crop’s which can be a source of carbohydrates and so that it can be used as an alternative to staple food. The objective of this research was to determine the level of knowledges, attitudes, and actions of sweet potato farmers in Sub-district Cilimus Kuningan Regency in an effort to manage plant pests and diseases. This research was conducted using a direct survey method in the field through interviews with sweet potato farmers using a structured questionnaire. Sampling locations were selected by purposive sampling, while sampling of respondents use a purposive sampling methods with a total of 60 respondents from four villages. The results showed that pesticides were used by the majority of respondents in management of plant pest organisms. Most respondents have known very well the culture practice of sweet potato, but their knowledge about natural enemies are limited. The majority of sweet potato farmers assume that “boleng pest” and bacterial wilt disease are difficult to control. Farming experience has a significant relationship with farmers' attitudes at the 5% and 10% levels. The participation in the integrated pest management field school (SLPHT) program has a significant relationship with farmers' actions in managing plant pest and disease of sweet potato.
Keyword: diseases, farmer, pest, sweet potato

Judul: Knowledge, Attitudes, and Practices of Farmers on IPM of Potato Plants (Solanum tuberosum L.) in Cikajang District, Garut Regency
Abstrak: Kentang (Solanum tuberosum L.) merupakan salah satu komoditas hortikultura unggulan yang banyak diproduksi di Indonesia. Salah satu sentra produksi kentang di Jawa Barat adalah Kabupaten Garut dengan wilayah penghasil tertinggi di Kecamatan Cikajang. Adanya serangan hama dan patogen pada pertanaman kentang menjadi salah satu penyebab penurunan produksi kentang. Penyakit utama pada pertanaman kentang diantaranya layu bakteri, layu Fusarium, dan hawar daun kentang. Sementara hama yang sering menyerang tanaman kentang diantaranya ulat tanah, lalat pengorok daun, serta penggerek daun dan umbi kentang. Upaya pengendalian yang dilakukan oleh petani umumnya berupa langkah preventif dan responsif dengan menekankan pada penggunaan pestisida. Penelitian ini bertujuan mendapatkan informasi mengenai karakteristik petani, teknik budi daya, serta pengetahuan, sikap, dan tindakan petani di Kecamatan Cikajang dalam mengendalikan hama dan penyakit kentang secara PHT. Metode yang digunakan dalam penelitian ini berupa pengumpulan data dengan metode wawancara terhadap 50 petani, serta pengamatan langsung ke lapangan untuk melihat hama dan penyakit yang dominan ditemukan pada pertanaman kentang. Analisis data dilakukan dengan menggunakan Microsoft Office Excel 2013 dan SPSS 26. Petani di Kecamatan Cikajang umumnya sudah memiliki tingkat pengetahuan yang baik terutama mengenai teknik budi daya. Sikap dan tindakan petani pun sudah cukup sesuai dengan komponen PHT, namun mayoritas petani masih bergantung pada pestisida sebagai alternatif pengendalian OPT (organisme pengganggu tanaman). Beberapa OPT yang ditemukan di lapangan adalah hawar daun (Phytophthora infestans), ulat grayak (Spodoptera litura), aphid, dan thrips., Potato (Solanum tuberosum L.) is one of the leading horticultural commodities which is widely produced in Indonesia. One of potato production centers in West Java is Garut Regency with the highest-producing area in Cikajang District. The presence of pests and pathogens in potato cultivation is one of the causes of a decrease in potato production. The main diseases in potato plantations include bacterial wilt, fusarium wilt, and potato leaf blight. While the pests that often attack potato plants include Agrotis ipsilon, leafminer flies, and Phthorimaea opeerculella. Control efforts carried out by farmers are generally in the form of preventive and responsive measures by emphasizing the use of pesticides. This study aims to obtain information on the characteristics of farmers, cultivation techniques, knowledge, attitudes, and practices of farmers in Cikajang District in controlling potato pests and diseases by IPM measurement. The method applyed in this study were data collection by interviewing 50 farmers, and observations to note which dominant pests and diseases were found in potato plantations. Data analysis was carried out using Microsoft Office Excel 2013 and SPSS 26. Farmers in Cikajang generally have good knowledge, especially regarding cultivation techniques. The attitudes and practices by farmers are also quite in accordance by the IPM components, but the majority of farmers still depend on pesticides as an alternative to control the pests and diseases at their farm. Several potato pests and diseases found in the field were leaf blight (Phytophthora infestans), armyworms (Spodoptera litura), aphids, and thrips.
Keyword: Cikajang district, farmers characters, potato pathogen

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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