Judul: The Application of [60Co] Gamma Irradiation for Controlling Macrosiphoniella sanborni (Gillette) on Chrysanthemum Cut Flower (Chrysanthemum morifolium cv. Jimba Lima)
Abstrak: Chrysanthemum cut flowers has high economic values and popular flower because it has many varieties with shape, size, color, and longer vase live of flower compared to other cut flowers. However, an infestation of Macrosiphoniella sanborni on chrysanthemum cut flowers can reduce the aesthetics of flowers, cause economic loss, and restrict export trading. Gamma irradiation [60Co] will be an alternative quarantine treatment against M. sanborni on chrysanthemum cut flowers. The advantages of gamma irradiation treatment including highly penetrating ability are considered to be effective for quarantine treatments, practical treatment, and the absence of any residue that could endanger consumers. This study was carried out to study M. sanborni’s life cycle with different temperatures and humidities, determine the effective dose of gamma irradiation [60Co] against M. sanborni, and evaluating of the effect on Chrysanthemum morifolium cv. Jimba Lima. The five steps of this research process were identification of M. sanborni, mass rearing and life cycle observation of M. sanborni, preliminary test on M. sanborni (nymphs and adult), sublethal dose test on M. sanborni (adult), and evaluation of their effects on quality of flowers. A preliminary test was performed by using a completely randomized design (CRD) with four replications at doses: 0, 50, 75, 100, 125, 150, 175, and 200 Gy using 50 individuals of M. sanborni in each replication. A sublethal dose test and evaluation of their effects on flower quality were performed by using CRD. The dosages used were 0, 200, 225, and 250 Gy with six replications. Data obtained showed that temperature on 28–34 oC dan RH 52–95% resulted in the shorter stadium of M. sanborni nymphs, longer of adult longevity, and higher fecundity rates of M. sanborni than rearing on temperature 27 0C and RH 33-35%. A preliminary test showed that the value of LD99 is 1092.982 Gy in adult. Radiotolerance of C. morifolium cv. Jimba Lima with doses below 300 Gy. Therefore, a sublethal dose test was performed because of the high lethal dose. Dose 200 Gy is the effective dose of gamma irradiation [60Co] against M. sanborni. Application of this dose on the first nymph showed the survival development reached until third nymph and it reached infertile adult when applicated on second, third, and fourth nymphs. Application on adult showed that it still can reproduce first progenies but in small amount and the survival development reached the first nymph. The sublethal dose of gamma irradiation (200 Gy) did not cause damage to the quality of chrysanthemum cut flower (C. morifolium cv. Jimba Lima) until 9 days.
Keyword: dosis efektif, efek iradiasi, kualitas bunga, serangga hama

Judul: Keefektifan Fosfin Formulasi Cair terhadap Aphis gossypii Glover dan Macrosiphoniella sanborni Gillette (Hemiptera: Aphididae) pada Bunga Potong Krisan
Abstrak: Bunga krisan merupakan salah satu tanaman hias yang banyak diminati oleh masyarakat karena memiliki nilai estetika dan ekonomi yang tinggi. Volume ekspor tanaman hias Indonesia, khususnya bunga krisan, masih relatif rendah dibandingkan dengan negara lain. Hal ini diakibatkan oleh beberapa kendala di antaranya adalah terbawanya organisme pengganggu tumbuhan (OPT) pada bunga yang diekspor. Beberapa hama dapat menyerang bunga krisan, dua di antaranya adalah kutudaun Aphis gossypii Glover dan Macrosiphoniella sanborni Gillette. Salah satu perlakuan karantina untuk membebaskan komoditas pertanian dari hama adalah fumigasi. Alternatif fumigan yang memiliki keefektifan yang baik adalah fosfin formulasi cair. Tujuan penelitian ini adalah menentukan konsentrasi dan lama pemaparan fosfin formulasi cair yang efektif mematikan A. gossypii dan M. sanborni pada bunga potong krisan serta mengevaluasi kualitas bunga yang diperlakukan dengan fumigan tersebut. Penelitian dilaksanakan dalam 5 tahapan: (1) Identifikasi serangga uji; (2) Perbanyakan A. gossypii dan M. sanborni; (3) Uji pendahuluan terhadap fase nimfa instar III dan imago; (4) Aplikasi konsentrasi dan lama pemaparan fosfin formulasi cair terhadap fase nimfa instar III dan imago A. gossypii dan M. sanborni dan; (5) Uji validasi konsentrasi dan lama pemaparan fosfin formulasi cair yang efektif serta mengevaluasi pengaruh perlakuan terhadap kualitas bunga potong krisan. Uji pendahuluan menunjukkan bahwa pada konsentrasi tertinggi 300 ppm, aplikasi fosfin formulasi cair terhadap imago atau nimfa instar III A. gossypii dan M. sanborni dengan lama pemaparan 6 jam dan 12 jam belum dapat mematikan 100% serangga uji. Pada uji lanjut dengan menggunakan konsentrasi 300-700 ppm, persentase mortalitas sebesar 100% terhadap nimfa instar III dan imago A. gossypii berturut-turut tercapai pada konsentrasi 500 ppm dan 400 ppm, sementara terhadap nimfa instar III dan imago M. sanborni berturut-turut tercapai pada konsentrasi 700 ppm dan 600 ppm, dengan lama pemaparan 12 dan 15 jam. Hasil analisis probit M. sanborni menunjukkan bahwa nilai LC50 dan LC95 terendah ditunjukkan pada lama pemaparan 15 jam dengan nilai berturut turut 209.8 ppm dan 397.8 ppm untuk fase imago, sedangkan untuk fase nimfa instar III 213.3 ppm dan 539.4 ppm. Aplikasi fosfin formulasi cair terhadap A. gossypii dan M. sanborni menyebabkan kematian 100%, berturut-turut pada konsentrasi 500 ppm dan 700 ppm, dengan lama pemaparan 12 jam. Konsentrasi hingga 700 ppm dengan lama pemaparan hingga 18 jam tidak berdampak buruk terhadap kualitas bunga potong krisan.
Keyword: fumigasi, fumigan, konsentrasi, lama pemaparan, kematian

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
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