Judul: Incidence and Severity of Leaf Spot Disease on Banana Plants (Musa spp.) at the IPB Experimental Garden Sukamantri, Bogor, West Java
Abstrak: Banana (Musa spp.) is one of the horticultural commodities that consumed by many people in Indonesia. Pests and diseases affects the quality of banana production. This study aims to identify the cause of leaf spot disease in banana plants and determine the incidence and severity of the disease. This research was conducted at the IPB experimental field station, in Sukamantri Village, Tamansari District, Bogor Regency, West Java. Observations of disease progression were conducted from September to October 2022 for five consecutive weeks. Identification of the cause of the disease is done by taking samples of symptomatic banana leaves, then further identified in the laboratory. Disease incidence and severity data were tabulated using Microsoft Office Excel 2013 and analyzed descriptively. Two types of leaf spot disease were identified, i.e. cordana and sigatoka leaf spot. Cordana leaf spot only infects Raja Bulu variety while sigatoka leaf spot infects Raja Bulu, Mas Kirana, and Ambon Kuning varieties. The incidence of cordana leaf spot disease caused by Cordana musae reaches 100% with an average disease severity of 30.66-67.70%. The incidence of sigatoka leaf spot caused by Mycosphaerella musicola in Raja Bulu variety was 62.96-66.67%, while in Mas Kirana and Ambon Kuning varieties reached 100% with the average severity of disease in Raja Bulu variety ranging from 9.62-17.33%, in Mas Kirana variety 31.38-62.00%, and in Ambon variety 33.17-67.05%.
Keyword: bercak cordana, bercak daun sigatoka, Cordana musae, identifikasi, Mycosphaerella musicola

Judul: Fusarium Wilt Disease of Banana in Binjai, North Sumatera
Abstrak: Tanaman pisang merupakan salah satu komoditas hortikultura penting dan bernilai ekonomi tinggi di Indonesia. Provinsi Sumatera Utara merupakan daerah sentra produksi pisang terbesar kedua di Pulau Sumatera dengan luas lahan mencapai 1 294 ha. Permasalahan organisme pengganggu tanaman (OPT) pada pertanaman pisang telah menyebabkan penurunan luas panen nasional sebesar 2 299 ha dengan total serangan mencapai 70% pada tahun 2018. Salah satu penyakit penting dalam budidaya tanaman pisang adalah penyakit layu fusarium yang sering juga disebut penyakit panama disebabkan oleh Fusarium oxysporum f. sp (Foc). Tujuan penelitian ini adalah menghitung kejadian penyakit layu pada tanaman pisang, mendapatkan informasi pengetahuan petani pisang terhadap penyakit layu, serta mengetahui praktik budidaya yang berkaitan dengan kejadian penyakit di lapang. Penelitian dilakukan di 5 kecamatan yaitu Kecamatan Binjai Utara, Binjai Timur, Binjai Selatan, Binjai Kota, dan Binjai Barat. Metode dilakukan dengan mewawancarai petani, menghitung kejadian penyakit, serta mengamati gejala tanaman terinfeksi. Hasil penelitian ini menunjukkan penyakit layu fusarium pada tanaman pisang telah tersebar hampir di seluruh kecamatan di Kota Binjai. Umur tanaman, varietas, pemupukan organik dan kondisi gulma pada pertanaman pisang berkaitan dengan kejadian penyakit layu fusarium di Kota Binjai. Sebanyak 70% petani tidak mengetahui secara pasti penyebab penyakit layu fusarium pada tanaman pisang., Banana is one of important and high economic value of horticutural product of Indonesia. North Sumatera is the second largest banana producing area in Sumatera reaching 1 294 ha. Pest and disease cause a decrease of the national production area of 2 299 ha with total attacks reaching 70%. One of the important diseases in banana cultivation is fusarium wilt which known as panama diseases, caused by Fusarium oxysporum f. sp. cubense. This research aimed to assess the incidence of fusarium wilt disease, farmers knowledge, and examine the agronomic practices that relate to the incidence of fusarium wilt disease in the field. The research was done in Binjai Utara, Binjai Timur, Binjai Selatan, Binjai Kota, and Binjai Barat district. The methods of this research consisted of farmers interview, field observation, and observation of symptom the infected plants. The result of this research indicate that fusarium wilt disease of banana has spread throughout the distric of Binjai. The age of plant, varieties of banana, aplication of organic fertilization, and weed density related to the incidence of fusarium wilt disease in Binjai. Around 70% of interviewed farmers did not know the casual agent of fusarium wilt disease of banana in Binjai.
Keyword: Fusarium oxysporum f. sp. cubense, Gejala, Kejadian, Varietas

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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