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: The Potential of Endophytic Fungus Nigrospora sp. in Supressing Blast Disease Caused by Pyricularia oryzae on Rice
Abstrak: Penyakit blas (Pyricularia oryzae) merupakan salah satu penyakit penting pada tanaman padi yang dapat menyebabkan kehilangan hasil antara 1-50% di dunia. Pengendalian penyakit blas dengan menggunakan varietas tahan dan penggunaan fungisida dinilai masih belum efektif karena variasi genetik penyebabnya yang tinggi. Pengendalian hayati diharapkan mampu menjadi alternatif untuk menekan cendawan ini salah satu diantaranya menggunakan cendawan endofit. Penelitian ini bertujuan menguji potensi cendawan endofit Nigrospora sp. dalam menekan penyakit blas yang disebabkan P. oryzae. Penelitian dilaksanakan di CV. WiSH Indonesia dari bulan Februari sampai Oktober 2021. Penelitian terdiri dari beberapa tahapan, yaitu 1) Perbanyakan propagul Nigrospora sp., 2) penyiapan suspensi P. oryzae, 3) uji penghambatan pertumbuhan P.oryzae pada tanaman padi. Sebagai pembanding digunakan tanaman yang diberi perlakuan fungisida berbahan aktif trisiklazol dan tanaman kontrol yang tidak diberi perlakuan. Pengamatan yang dilakukan meliputi intensitas penyakit, kolonisasi cendawan endofit pada potongan daun, dan parameter pertumbuhan tanaman padi. Meskipun kejadian penyakit mencapai 100 % untuk semua perlakuan pada pengamatan terakhir (7 minggu setelah inokulasi), namun demikian tingkat keparahannya tertekan oleh perlakuan Nigrospora. Cendawan endofit Nigrospora sp. mampu menekan keparahan penyakit blas daun sebesar 28-32 % dan blas leher sebesar 20-30% jika dibandingkan dengan kontrol. Penekanan penyakit blas paling stabil mulai dari awal pengamatan sampai akhir pengamatan ditunjukkan oleh perlakuan perendaman benih + penyemprotan Nigrospora sp. Kemampuan cendawan endofit dalam mengolonisasi tanaman padi pada perlakuan Nigrospora sp. berkisar antara 40-55%. Selain dapat menekan pertumbuhan penyakit blas, perlakuan cendawan endofit Nigrospora sp. juga menunjukkan pengaruh positif terhadap parameter pertumbuhan tanaman, antara lain tinggi tajuk, jumlah anakan dan jumlah anakan produktif, bobot gabah basah dan bobot gabah kering., Blast disease (Pyricularia oryzae) is a disease that attacks rice plants which can cause losses of 1-50% in the world. Blast disease control using resistant varieties and the use of fungicides are still considered ineffective due to the high genenetic variability of the pathogen. Biological control is expected to be one of the alternative control measures, one of which is using endophytic fungi. This study aims to determine the potential of the endophytic fungus Nigrospora sp. in suppressing blast disease caused by P. oryzae. The research was carried out at CV. WiSH Indonesia from February to October 2021. The study consisted of some activities, including propagule reproduction of Nigrospora sp., preparation of P.oryzae conidial suspension, and in planta test of the ability of Nigrospora sp. in blast disease suppression. As comparison treatments, plants were treated with fungicides (active ingredient tricyclazole) and control plants without any treatments. Observations were also made on the endophytic fungal colonization test as well as the rice plant growth parameters. Even though the incidence of the disease reached 100% for all treatments at the last observation (7 weeks after inoculation), however the severity was suppressed by the Nigrospora treatment. The endophytic fungus Nigrospora sp. was able to reduce the severity of leaf blast disease by 28 -32% and neck blast by 20-30% when compared to controls. The most stable suppression of blast disease from the beginning of the observation to the end of the observation was indicated by seed treatment + spraying treatment of Nigrospora sp.
Keyword: biological control agent, neck blast, seed treatment, yield loss

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