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: Effectiveness of Cropcoat Insecticides on Phenacoccus solenopsis Chrysanthemum Mealybugs (Hemiptera: Pseudococcidae)
Abstrak: Krisan menjadi komoditas utama florikultura dengan nilai ekspor tertinggi di Indonesia. Salah satu hama penting pada tanaman ini adalah Phenacoccus solenopsis (Hemiptera: Pseudococcidae). Pengendalian menggunakan campuran sabun dan insektisida nabati sering dilakukan oleh petani krisan, masih belum cukup berhasil dalam mengendalikan hama tersebut. Penelitian ini bertujuan menguji keefektifan insektisida Cropcoat dan sabun baik yang diaplikasikan secara berurutan maupun bersamaan terhadap P. solenopsis. Pengujian dilakukan melalui tiga perlakuan yang meliputi aplikasi insektisida Cropcoat tunggal, aplikasi sabun sebelum penyemprotan insektisida Cropcoat, dan aplikasi campuran sabun dengan insektisida Cropcoat. Perlakuan insektisida Cropcoat dilakukan pada tiga taraf konsentrasi yaitu 0,75%, 1%, 1,5% dan kontrol yang diulang 6 kali, kemudian data dianalisis probit untuk menentukan nilai LC50 dan LC95 dari masing-masing perlakuan pada 120 jam setelah pengamatan (JSP). Hasil penelitian menunjukkan bahwa seluruh perlakuan insektisida Cropcoat yang diuji dapat mengakibatkan kematian P. solenopsis pada awal hari pengamatan. Insektisida Cropcoat memiliki sifat antifeedant dengan toksik rendah yang dapat mematikan serangga. Namun, insektisida Cropcoat termasuk golongan yang kurang efektif dalam mengendalikan kutu putih P. solenopsis pada tanaman krisan. Nilai LC50 dan LC95 pengujian insektisida Cropcoat yang diaplikasikan setelah sabun cair berturut-turut sebesar 4,07% dan 7,62%, yang menunjukkan bahwa konsentrasi tersebut merupakan konsentrasi terbaik untuk mematikan nimfa P. solenopsis instar ke-3., Chrysanthemum is one of the most popular floricultural commodities with the highest export value in Indonesia. One of the important pests on this plant is Phenacoccus solenopsis (Hemiptera: Pseudococcidae). The mixture of liquid soap and insecticides is often used by chrysanthemum farmers to control insect pests. This study aimed to verify the efficacy of insecticides Cropcoat and soap, either by single application, sequentially or simultaneously as a control against P. solenopsis. The tests were carried out on three treatments including the application of a single Cropcoat insecticide, application soap before spraying Cropcoat insecticide, and application of soaps mix with Cropcoat insecticide. Cropcoat insecticides were carried out at three concentration levels, 0.75%, 1%, 1.5% and control which each treatment repeated 6 times, then the data were analyzed using probit analysis to determine the LC50 and LC95 values of each treatment at 120 hours after observation. The results showed that all Cropcoat insecticides treatments resulted in insect death on the first day of observation. Cropcoat insecticide has antifeedant properties with low toxicity which can kill insects. However, Cropcoat insecticides were less effective in controlling P. solenopsis on chrysanthemum. The LC50 and LC95 values of insecticide Cropcoat tested which were applied after the liquid soap were 4.07% and 7.62%, respectively, which indicated that these concentrations were the best concentrations to kill the 3 rd instar P. solenopsis nymphs.
Keyword: floriculture, LC values, mortality, soaps

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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