Judul: Pest and Disease Attacks, Pesticide Application, and Rice Production in Pekalongan City, Central Java
Abstrak: Tanaman padi (Oryza sativa L.) merupakan tanaman pangan pokok di Indonesia. Tanaman padi pada umumnya tidak dapat berproduksi secara optimal karena berbagai kendala, seperti kesuburan lahan, praktik budidaya, dan serangan hama dan penyakit tanaman. Serangan hama dan penyakit tanaman dapat menyebabkan kerugian yang sangat tinggi. Strategi pengendalian yang sering dilakukan oleh petani salah satunya melalui aplikasi pestisida sintetik. Penelitian ini bertujuan mengetahui jenis hama dan penyakit penting, luas serangan hama dan penyakit, jenis dan aplikasi pestisida, serta produktivitas tanaman padi di Kota Pekalongan, Jawa Tengah. Data serangan hama dan penyakit, penggunaan pestisida, dan produktivitas padi diperoleh dari Dinas Pertanian Kota Pekalongan serta literatur elektronik. Hama dan penyakit penting yang menyerang tanaman padi di Kota Pekalongan antara lain penggerek batang padi, wereng batang cokelat, keong mas, burung, tikus, penyakit kerdil rumput, dan hawar daun bakteri. Berdasarkan luas serangan OPT, wereng batang cokelat merupakan hama yang dominan menyerang tanaman padi di Kota Pekalongan. Terdapat 11 bahan aktif pestisida yang digunakan oleh petani padi di Kota Pekalongan, yang sebagian besar merupakan jenis insektisida. Insektisida Abacel 18 EC yang berbahan aktif abamektin merupakan insektisida yang rata-rata volume penggunaannya tinggi. Curah hujan juga menjadi salah satu faktor yang mempengaruhi produktivitas padi, semakin tinggi curah hujan, maka produksi padi semakin menurun. Tiga jenis pupuk,yaitu phonska, urea, dan SP-36 dan padi varietas IR-42 banyak digunakan oleh petani padi di Kota Pekalongan., Rice (Oryza sativa L.) is a primary food crop in Indonesia. Rice plants are generally unable to produce optimally due to various factors, such as soil fertility, cultivation pratices, weather, and plant pests and diseases. Pests and diseases could cause significant production losses and synthetic pesticide was one of the current prevention methods used by farmers. The aim of this study was reporting the main pests and diseases and their attacks, pesticides application, and the rice production in Pekalongan, Central Java. The data were obtained from Pekalongan Agricultural Office and some electronic references. There were seven main pests and diseases attacking the rice plants in Pekalongan, including rice stem borer, brown planthopper, birds, rats, golden snails, bacterial leaf blight, and grassy stunt virus disease. According to the area of pest attack, the brown planthopper was a dominant pest attacking rice plants. There were 11 pesticide active ingredients used by rice farmers, and most of which were insecticides. Abacel 18 EC (a.i abamectin) is an insecticide with a high average volume used. The rainfall was also become one of the factors affecting the rice productivity, the higher the rainfall, the lower the rice production. Three types of fertilizer, phonska, urea, and SP-36 are used by rice farmers in Pekalongan. Meanwhile, IR-42 was the commonly rice variety planted in Pekalongan.
Keyword: active ingredient, brown planthopper, rainfall

Judul: National Rice Production and its Important Disease Intensity in Sukabumi District
Abstrak: Produksi beras sebagai sumber pangan pokok ditingkatkan untuk memenuhi kebutuhan masyarakat Indonesia yang jumlah penduduknya selalu meningkat. Produksi padi di Indonesia berfluktuasi karena berbagai faktor abiotik dan biotik, termasuk hama dan penyakit. Produksi beras nasional Indonesia meningkat selama periode 2011-2017, kemudian menurun secara signifikan pada 2018-2020. Penurunan produksi beras juga terjadi di lima provinsi penghasil beras terbesar yaitu Jawa Tengah, Jawa Timur, Jawa Barat, Sulawesi Selatan, dan Sumatera Selatan pada periode 2018-2021. Petani padi di Kecamatan Jampangkulon dan Cibitung Kabupaten Sukabumi menerapkan cara budidaya dan pengelolaan OPT secara konvensional, yaitu mengandalkan pupuk kimia dan pestisida sintetik. Penyakit penting yang ditemukan pada padi varietas lokal, Trisakti dan IR64 dari pengamatan lapangan di Kabupaten Sukabumi adalah bercak daun lonjong atau blas jamur oleh Pyricularia oryzae dan hawar daun bakteri oleh Xanthomonas oryzae pv. oryzae. Insidensi penyakit P. oryzae mencapai 100% pada ketiga varietas dengan tingkat severitas berkisar 60,7-66,7% pada daun dan 52,3-60% pada malai, sedangkan hawar bakteri menyebabkan insidensi 76,7-93,3% dan severitas 33,0- 64,4%. Varietas padi lokal paling tahan terhadap P. oryzae dibandingkan dua varietas lainnya, sedangkan Trisakti relatif lebih tahan penyakit hawar daun bakteri. Varietas IR64 paling rentan terhadap kedua penyakit tersebut dibandingkan dengan varietas lainnya. Berdasarkan analisis usahatani dan rasio keuntungan terhadap biaya (rasio B/C), varietas yang paling menguntungkan berturut-turut adalah lokal, IR64 dan Trisakti. Kata kunci: Rasio B/C, Xanthomonas oryzae pv. oryzae, Pyricularia oryzae, insidensi, severitas, fluktuasi produksi padi, Rice production as a staple food source is increased to meet the needs of the Indonesian people, whose population is always increasing. Rice production in Indonesia fluctuates due to various abiotic and biotic factors, including pests and diseases. Indonesia's national rice production increased during the 2011-2017 period, then decreased significantly in 2018-2020. The decline in rice production also occurred in the five largest rice producing provinces, namely Central Java, East Java, West Java, South Sulawesi and South Sumatra in the period 2018-2021. Rice farmers in Jampangkulon and Cibitung Subdistricts, Sukabumi Regency, apply conventional methods of cultivating and managing pests, which rely on chemical fertilizers and synthetic pesticides. The important diseases found in local rice varieties, Trisakti and IR64 from field observation in Sukabumi District were fungal oval leaf spot or blast by Pyricularia oryzae and bacterial leaf blight by Xanthomonas oryzae pv. oryzae. The incidence of disease by P. oryzae reached 100% in the three varieties with severity ranging from 60.7-66.7% on leaves and 52.3-60% on panicles, while bacterial blight caused incidence of 76.7-93.3% and severity 33.0-64.4%. The local rice variety was most resistant to P. oryzae than the other two varieties, while Trisakti was relatively most resistant to bacterial leaf blight. The IR64 variety was the most susceptible to both diseases compared to the other varieties. Based on the analysis of farming and benefit- cost ratio (B/C ratio), the most profitable varieties were local one, followed by IR64 and Trisakti, respectively. Keywords: B/C ratio, Xanthomonas oryzae pv. oryzae, Pyricularia oryzae, incidence, severity, rice production fluctuation
Keyword: B/C ratio, Xanthomonas oryzae pv. oryzae, Pyricularia oryzae, incidence, severity, rice production fluctuation

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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