Judul: Strawberry Crop Management by Farmers and Its Leaf Spot Disease Intensity in Tinggimoncong District Gowa Regency
Abstrak: Stroberi (Fragaria x ananassa) merupakan komoditas hortikultura bernilai ekonomi tinggi di Indonesia. Sulawesi Selatan sebagai penghasil terbesar kelima di Indonesia mengalami penurunan 50,25% produksi dari 2019 ke 2020 yaitu sebesar 400 dan 199 ton. Salah satu kendala produksi stroberi adalah gangguan organisme pengganggu tanaman (OPT) termasuk penyakit tanaman. Penelitian ini bertujuan mempelajari pengelolaan tanaman stroberi oleh petani dan intensitas penyakit bercak daun stroberi di sentra produksi Kecamatan Tinggimoncong, Kabupaten Gowa. Petani pelaku usahatani stroberi pada umumnya memiliki tingkat usia produktif 30-50 tahun dengan pengalaman bertani kurang dari 10 tahun. Stroberi varietas Rosalinda banyak ditanam baik secara monokultur maupun secara tumpang sari di lahan yang tidak terlalu luas dengan kepemilikan berkisar antara 200-1000 m2. Budidaya stroberi masih bersifat konvensional dan mengandalkan pupuk kimia dan pestisida sintetik. Penyakit bercak daun pada tanaman stroberi di Kecamatan Tinggimoncong disebabkan oleh cendawan Neopestalotiopsis sp.. Hasil penelitian menunjukkan bahwa insidensi penyakit bercak daun stroberi rata-rata 77.27% dengan tingkat severitas 15,90 – 35.22%. Tingkat serangan penyakit tertinggi terjadi pada lahan pengamatan dengan pola tanam tumpangsari 3 tanaman (A), sedangkan tingkat serangan penyakit terendah terjadi di lahan pengamatan tumpangsari 2 jenis tanaman (B). Perkembangan penyakit bercak daun pada tanaman stroberi diduga dipengaruhi faktor pola tanam dan kondisi cuaca (kelembapan dan suhu). Informasi mengenai dinamika perkembangan penyakit pada tanaman stroberi dapat diajukan sebagai acuan dalam pengambilan tindakan pengendalian oleh instansi dan pihak terkait di Kabupaten Gowa., Strawberry (Fragaria x ananassa) is an horticultural commodity with high economic value in Indonesia. South Sulawesi as the fifth largest producer in Indonesia experienced a 50.25% decline in production from 2019 to 2020, which was 400 and 199 tons, respectively. One of the constraints to strawberry production is plant pest and disease problem, including fungal leaf spot disease. The objective is to study the management of strawberry plants by farmers and the intensity of strawberry leaf spot disease in the production center of Tinggimoncong District, Gowa Regency. Farmers who grow strawberry generally have a productive age of 30-50 years with less than 10 years of farming experience. Strawberries of the Rosalinda variety are widely grown both monocultures and intercropping on a small area of land with holdings ranging from 200-1000 m2. Strawberry cultivation is still conventional and relies on chemical fertilizers and synthetic pesticides. Leaf spot disease on strawberry plants in Tinggimoncong District was caused by the fungus Neopestalotiopsis sp.. The results showed that the incidence of strawberry leaf spot disease was on average 77.27% with a severity level of 15.90 – 35.22%. The highest rate of disease occurred in the observation area with an intercropping pattern of 3 plants (A), while the lowest disease attack rate occurred in the observation area with an intercropping of 2 types of plants (B). The development of leaf spot disease on strawberry plants is thought to be influenced by cropping patterns and weather conditions (humidity and temperature). Information regarding the dynamics of disease development in strawberry plants can be submitted as a reference in taking control measures by agencies and related parties in Gowa Regency.
Keyword: Insidensi, Severitas, Karakteristik petani, Pola tanam, Neopestalotiopsis sp.

Judul: Pengendalian Hama dan Penyakit Tanaman Stroberi dengan Sistem Biointensif di La Fresa Farm, Kabupaten Bandung
Abstrak: Pengendalian hama dan penyakit stroberi (Fragaria X ananassa) yang umum dilakukan adalah dengan penyemprotan pestisida yang dapat menimbulkan dampak negatif terhadap lingkungan. Hal ini mendorong pengembangan produksi stroberi yang ramah lingkungan dengan sistem biointensif. Penelitian ini bertujuan menginventarisasi hama dan penyakit serta mengetahui pengaruh sistem biointensif terhadap hama, penyakit dan produksi stroberi. Pengamatan dilakukan setiap minggu sebanyak tujuh kali dengan menginventarisasi jenis dan populasi hama serta intensitas penyakit pada tiga lahan dengan metode penanaman berbeda, yaitu rak, bedengan, dan polybag. Pengujian biointensif dilaksanakan menggunakan rancangan acak kelompok dengan tiga perlakuan kombinasi mikroba dan solarisasi serta perlakuan pestisida kimia dan kontrol. Mikroba agens hayati yang digunakan adalah Bacillus polymixa, Pseudomonas fluorescens, Rhizobium sp., Lecanicillium sp., Bacillus thuringiensis, Serratia marcescens dan Trichoderma hamatum. Tungau, thrips, dan ulat grayak ditemukan dengan populasi masing-masing 0,31-1,74 ekor/tanaman, 0,08-0,51 ekor/tanaman, dan 0,08-1,63 ekor/tanaman. Penyakit yang dominan ditemukan adalah bercak daun (Neopestalotiopsis sp.) dengan insidensi 41-100% dan severitas 10,25-38%. Hasil pengujian menunjukkan bahwa solarisasi tanah dapat meningkatkan suhu tanah hingga 58,50 oC. Sistem biointensif dapat menekan severitas penyakit bercak daun dan ulat grayak serta meningkatkan produksi lebih baik dibandingkan kontrol. Produksi tertinggi terdapat pada perlakuan BIO 2 dan BIO 3 sebesar 37,14 dan 36,96 g/tanaman., Strawberry (Fragaria X ananassa) pests and diseases control are commonly carried out by spraying pesticides that can cause negative impacts on the environment. This encourages the development of environmentally friendly strawberry production with a biointensive system. This study aims to inventory pests and diseases and to determine the influence of biointensive systems on pests, diseases and strawberry production. Observations were carried out seven times a week by inventorying the types, populations of pests and disease intensity in three fields with different planting methods, namely racks, beds and polybags. The biointensive test was carried out using a randomized block design with three treatments combining microbes and solarization as well as chemical pesticide treatments and control. The biocontrol microbes used include Bacillus polymixa, Pseudomonas fluorescens, Rhizobium sp., Lecanicillium sp., Bacillus thuringiensis, Serratia marcescens and Trichoderma hamatum. Mites, thrips, and armyworms were found with populations of 0,31-1,74 individuals/plant, 0,08-0,51 individuals/plant and 0,08-1,63 individuals/plant, respectively. The dominant disease found was leaf spot (Neopestalotiopsis sp.) with an incidence of 41-100% and a severity of 10,25-38%. The test results showed that soil solarization can increase soil temperature up to 58,50 oC. The biointensive system can suppress the severity of leaf spot and armyworm and increase production better than control. The highest production was found at BIO 2 and BIO 3 treatments of 37,14 and 36,96 g/plant.
Keyword: Bacillus polymixa, Bacillus thuringiensis, Lecanicillium sp., Pseudomonas fluorescens, Trichoderma hamatum

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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