Judul: Penghambatan Penyakit Hawar Daun Bakteri dan Pemacuan Pertumbuhan Tanaman Padi dengan Biopestisida Berbahan Aktif Bacillus subtilis dan Pseudomonas fluorescens
Abstrak: Xanthomonas oryzae pv. oryzae adalah bakteri patogen tanaman padi yang menjadi salah satu penyakit utama padi di Indonesia dan beberapa negara. Berbagai upaya telah dilakukan untuk mengendalikan penyakit ini, namun belum memberikan hasil yang maksimal dalam menekan perkembangan dan penyebaran penyakit. Untuk mendapatkan pengendalian yang lebih efektif dan aman bagi lingkungan diperlukan pengendalian alternatif yang efektif dan ramah lingkungan. Dua isolat bakteri biokontrol yang telah terbukti sebagai agens hayati dan efektif menekan berbagai penyakit tanaman adalah P. fluorescens RH4003 dan B. subtilis AB89. Tujuan penelitian ini adalah untuk mengetahui pengaruh biopestisida yang berbahan aktif B. subtilis dan P. fluorescens dalam menekanan penyakit hawar daun bakteri pada tanaman padi, pengaruhnya terhadap bobot basah dan kering tanaman, dan perkecambahan biji. Percobaan disusun dalam rancangan acak lengkap faktorial dengan tiga ulangan. Hasil penelitian menunjukkan bahwa formulasi tepung dan formulasi cair Bacillus subtilis dan Pseudomonas fluorescens efektif dalam menekan penyakit hawar daun bakteri. Perendaman benih dalam formulasi bakteri biokontrol dengan waktu 5 jam dan 10 jam tidak berpengaruh signifikan terhadap penekanan penyakit hawar daun bakteri dan daya kecambah benih. Perendaman berpengaruh signifikan terhadap bobot basah dan bobot kering tanaman.
Keyword: Formulasi biopestisida, keparahan penyakit, pengendalian hayati, PGPR, Xanthomonas oryzae pv. oryzae

Judul: Studi Keefektifan Formulasi Spora Bacillus Subtilis Sebagai Agens Pengendali Hayati Penyakit Hawar Daun Bakteri dan Hawar Pelepah Serta Pemicu Pertumbuhan Pada tTanaman Padi:
Abstrak: In controlling rice diseases, most farmers still rely on chemical pesticide as the solution. However, because of high cost and negative effects of chemical pesticide, biocontrol is one of alternative solutions. Bacillus subtilis is a model of biocontrol agents to control many plant diseases, because its ability to produce antimicrobial and plant growth promoting substances. This research aimed to examine the effectiveness of Indonesian isolate of B. subtilis spore formulation through seed treatment and foliar spray with different frequencies and concentrations to control bacterial leaf blight (Xanthomonas oryzae pv. oryzae) and sheath blight (Rhizoctonia solani) diseases of rice. The influence of the formulation application to plant growth and other microbes was evaluated. The experiment was conducted in greenhouse and field with factorial experimental design. Seed treatment, concentration and frequency of application and its interaction effectively suppressed bacterial leaf blight and sheath blight diseases, increased plant growth and reduced yield loss. The concentration at 2% is recommended for applying the formulation. The interval of application at 1 and 2 week showed equal effect to disease suppression and increased yield. Application of B. subtilis spore formulation increased yield of Ciherang, Cisantana, and Sintanur as much as 26,3%, 18,5%, and 15,4% respectively. Application of the formulation gave no significant effect to microbe diversity in the field.
Keyword: 

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
Keyword: