Judul: Controlling of Blast Disease (Pyricularia oryzae Cav.) in Lowland Rice with Several Cultivation Methods
Abstrak: Padi merupakan sumber pangan utama yang penting bagi masyarakat Indonesia. Oleh karena itu keberlanjutan produksinya dari tahun ke tahun selalu menjadi perhatian bagi pemerintah. Faktor yang dapat memengaruhi produktivitas padi salah satunya adalah serangan hama dan penyakit tanaman. Penyakit blas yang disebabkan oleh Pyricularia oryzae merupakan penyakit penting pada tanaman padi di negara-negara penghasil padi di seluruh dunia. Saat ini terdapat tiga cara utama yang dapat dilakukan untuk mengendalikan penyakit blas, yaitu teknik budidaya, penggunaan fungisida dan varietas tahan. Percobaan lapangan ini dilakukan untuk mengetahui pengaruh beberapa teknik budidaya tanaman padi terhadap perkembangan penyakit blas. Percobaan ini dilakukan dengan menggunakan rancangan acak lengkap satu faktor dengan tiga perlakuan dan tiga ulangan. Perlakuan tersebut yaitu P1 (pengembalian jerami, penggunaan pupuk hayati, pengurangan pupuk sintetis, tanpa penggunaan pestisida sintetis), P2 (pengembalian jerami, penggunaan pupuk dan pestisida sintetis sesuai dengan cara petani setempat), dan P3 (jerami dibakar, penggunaan pupuk dan pestisida sintetis sesuai dengan cara petani setempat). Data tingkat serangan blas daun, blas leher, tinggi tanaman, jumlah anakan total dan jumlah anakan produktif pada setiap ulangan diamati pada 50 rumpun tanaman contoh yang ditentukan secara sistematis. Pengamatan tersebut dilakukan pada umur 30, 40, 60, 80, dan 90 hari setelah pindah tanam. Perlakuan yang diuji cobakan tidak menunjukkan perbedaan yang nyata terhadap insidensi dan keparahan penyakit, baik blas daun maupun blas leher, tinggi tanaman, total jumlah anakan serta jumlah anakan produktif. Perlakuan P2 menunjukkan produktivitas gabah kering panen maupun kering giling yang paling tinggi dibandingkan dua perlakuan lainnya., Rice is an important main food source for Indonesian people. Therefore, the sustainability of production from year to year is always a concern for the government. One of the factors that may affect rice productivity is the presence of pests and plant diseases. Blast disease caused by Pyricularia oryzae is an important disease in rice-producing countries around the world. At present, there are three primary control measures that may be applied, namely cultural practices, fungicides and cultivar resistance. This field experiment was conducted to determine the effect of several rice cultivation techniques on the development of blast disease. This experiment was conducted using a one-factor completely randomized design with three treatments and three replications. The treatments were P1 (returning straw to the field, using biological fertilizers, reducing synthetic fertilizers, without the use of synthetic pesticides), P2 (returning straw to the fields, using synthetic fertilizers and pesticides with the dosage as commonly practiced by local farmers), and P3 as comparison treatment (cultivation techniques commonly practiced by local farmers include burning straw, use of synthetic fertilizers and pesticides with doses as commonly practiced by local farmers). Data on incidence and severity of leaf blast and neck blast, plant height, number of total tillers and number of productive tillers in each replication were observed on 50 sample plants which were determined systematically. The observations were made at 30, 40, 60, 80, and 90 days after transplanting. The treatments tested did not show significant differences in the incidence and severity of both leaf and neck blast disease, plant height, total number of tillers and number of productive tillers. The P2 treatment showed
Keyword: bio-fertilizer, blast disease, straw return, synthetic fertilizer, synthetic pesticides

Judul: Disease Incidence and Severity of Blast (Pyricularia  oryzae) and Bacterial Leaf Blight (Xanthomonas oryzae pv. oryzae) on Rice  Plants in Gebang and Kuripan Villages, Pekalongan City, Central Java
Abstrak: Padi adalah sumber pangan penting bagi masyarakat di dunia terutama masyarakat Indonesia. Peningkatan produktivitas padi memiliki beberapa kendala seperti adanya penyakit tanaman. Terdapat dua penyakit penting padi di Indonesia yaitu blas (Pyricularia oryzae) dan hawar daun bakteri (Xanthomonas oryzae pv. oryzae). Penelitian ini bertujuan mengukur tingkat insidensi dan keparahan penyakit blas dan hawar daun bakteri pada tanaman padi di Kota Pekalongan, Jawa Tengah. Pengamatan di lapangan dilakukan pada 5 petak contoh di Desa Gebang dan 5 petak di Desa Kuripan. Pengamatan juga dilakukan terhadap bobot 1000 butir gabah kering panen dari tanaman contoh. Selain pengamatan di lapangan juga dilakukan wawancara dengan petani. Di Desa Gebang varietas yang ditanam adalah Varietas Inpari 43, sedangkan di Desa Kuripan ditanam varietas Inpari 42. Hasil penelitian menunjukkan bahwa serangan P. oryzae dan X. oryzae pv. oryzae ditemukan pada semua petak pengamatan. Keparahan penyakit blas pada lahan pengamatan di Desa Gebang relatif lebih tinggi (rata-rata 51.11%) dibandingkan dengan lahan pengamatan di Desa Kuripan (rata-rata 25.55%). Keparahan penyakit HDB pada lahan Desa Gebang juga relatif lebih tinggi (rata- rata 92%) dibandingkan dengan lahan pengamatan di Desa Kuripan (rata-rata 60.44%), Rice is an important crops as staple food in Indonesia. Increasing rice productivity has an important constraint such as plant diseases. Two important rice diseases in Indonesia are blast (Pyricularia oryzae) and bacterial leaf blight (Xanthomonas oryzae pv. oryzae). This study was aimed to measure the incidence and severity of blast and bacterial leaf blight diseases on rice plants in Pekalongan City, Central Java. As many as 5 sample plots of rice fields each in Gebang Village and Kuripan Village were observed. Observations were also carried out on the weight of 1000 dry-harvested grains from the sample plants. In Gebang plots were grown Inpari 43 variety, while in Kuripan plots were grown Inpari 42 variety. This study has shown that blast and bacterial leaf blight disease were observed in all observation plots. The severity of blast disease in the observation plots in Gebang Village was relatively higher (51.11%) than Kuripan Village (25.55%). Similarly BLB disease severity in Gebang Village was higher (92%) than in Kuripan Village (60.44%)
Keyword: Grain, Inpari 42, Inpari 43, Plots, Rice diseases

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology