Judul: Study of the Potential of Fungi Metarhizium anisopliae as a Biopesticide for Controlling Spodoptera frugiperda JE Smith (Lepidoptera: Noctuidae)
Abstrak: Kerusakan pada pertanaman jagung akibat serangan UGF (ulat grayak frugiperda) atau S. frugiperda dapat menurunkan produksi jagung hingga 20%. Pengendalian hama pada jagung biasanya dilakukan dengan aplikasi insektisida kimiawi. Namun penggunaan insektisida kimiawi memiliki dampak negatif, maka perlu dicari alternatif pengendalian berupa pemanfaatan agens hayati seperti cendawan entomopatogen Metarhizium anisopliae. Penelitian ini bertujuan untuk mengetahui potensi cendawan entomopatogen M. anisopliae sebagai agens pengendali hayati terhadap UGF. Pengujian di laboratorium dilakukan dengan tahapan perbanyakan serangga hama, perbanyakan isolat cendawan M. anisopliae, uji pendahuluan terhadap larva instar 4, lalu pengamatan mortalitas larva. Data tambahan diperoleh dari studi literatur untuk perbandingan dan pembahasan. Hasil uji pendahuluan menunjukkan bahwa M. anisopliae efektif untuk mengendalikan UGF yang ditunjukkan oleh mortalitas larva instar keempat yang mulai terjadi pada hari kelima setelah aplikasi. Larva UGF yang mati tertutup hifa berwarna hijau tua pada hari kesebelas. Fase larva yang masih muda lebih efektif terinfeksi oleh cendawan M. anisopliae. Kerapatan konidia 1 x 108 konidia/ml dinilai baik untuk mengendalikan S. frugiperda. Isolat yang berasal dari tanah memiliki tingkat infeksi yang lebih tinggi daripada isolat yang diambil dari habitat lain. Cendawan M. anisopliae mempunyai potensi yang tinggi sebagai salah satu biopestisida untuk mengendalikan S. frugiperda., Damage to maize crops due to attack by fall armyworms (FAW) or Spodoptera frugiperda can reduce maize production up to 20%. Pest management in corn is usually implemented by applying chemical insecticides. However, the use of chemical insecticides has a negative impact, so other alternative methods are needed. Pest management of FAW by using entomopathogenic fungus Metarhizium anisopliae is one chosen method. This research aimed to study the potential of the entomopathogenic fungus M. anisopliae as a biological control agent against the corn FAW. In the laboratory, the FAW were mass reared on young cob. Fungal isolates of M. anisopliae was purified using PDA. The 4th instar larvae of S. frugiperda were challenged against the fungal conidia. The additional data obtained from literature studies were used for analysis the effectiveness. Preliminary test of M. anisopliae resulted the mortality of fourth instar larvae on the fifth day and followed by the growth of green hyphae on the eleventh day post treatment. Young larvae were susceptible to be infected by the fungus. Conidial density 1 x 108 conidia/ml regarded effective to control S. frugiperda. Soil isolates had a higher infection rate than isolates obtained from other habitat. The results showed that the fungus M. anisopliae had a high potential as a biopesticide to control the S. frugiperda.
Keyword: conidial density, FAW, isolate, larvae, mortality

Judul: Effectiveness of the Entomopathogenic Fungi Metarhizium spp. on The Fall Armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae)
Abstrak: Ulat grayak jagung, Spodoptera frugiperda merupakan hama invasif yang menjadi ancaman serius bagi produksi jagung di Indonesia. Salah satu pengendalian alternatif sebagai upaya mengurangi penggunaan pestisida sintetik dengan memanfaatkan cendawan entomopatogen. Penelitian ini bertujuan untuk mengetahui keefektifan cendawan entomopatogen Metarhizium anisopliae dan M. robertsii terhadap mortalitas larva S. frugiperda. Lima tingkat kerapatan konidia yaitu 106 , 107 , 108 , 109 konidia/mL, dan kontrol diaplikasikan dengan metode semprot pada larva instar ketiga S. frugiperda. Mortalitas diamati setiap hari hingga delapan hari setelah aplikasi. Berdasarkan hasil pengujian, nilai LC50 pada M. anisopliae sebesar 3,22 x 108 konidia/mL dan M. robertsii sebesar 2,60 x 107 konidia/mL. Mortalitas S. fugiperda tertinggi terjadi pada perlakuan M. anisopliae dan M. robertsii terjadi pada perlakuan 109 konidia/mL sebesar 82 dan 100% dengan nilai LT50 berturut-turut 2,96 dan 1,82 hari. Kedua cendawan ini bersifat patogenik dan efektif terhadap S. frugiperda. Selain itu, cendawan entomopatogen M. robertsii lebih virulen terhadap larva S. frugiperda dibandingkan dengan M. anisopliae., The fall armyworm, Spodoptera frugiperda is an invasive pest that poses a serious threat to corn production in Indonesia. One alternative control method to reduce the use of synthetic pesticides is utilizing entomopathogenic fungi. This research aimed to study the effectiveness of the entomopathogenic fungi Metarhizium anisopliae and M. robertsii on the mortality of S. frugiperda larvae. Five levels of conidia density: 106 , 107 , 108 , 109 conidia/mL, and an untreated were spray-applied to third instar larvae of S. frugiperda. Insect mortality was observed daily for eight days after treatment. Based on the result, the LC50 value for M. anisopliae was 3.22 x 108 conidia/mL while for M. robertsii, it was 2.60 x 107 conidia/mL. The highest insect mortality M. anisopliae and M. robertsii treatments occurred at 109 conidia/mL by 82 and 100%, respectively. The value of LT50 values were 2.96 and 1.82 days, respectively. Both M. anisopliae and M. robertsii were entomopathogenic and effective to control S. frugiperda. Additionally, M. robertsii was more virulent to S. frugiperda larvae than those of M. anisopliae.
Keyword: biological agents, M. anisopliae, M. robertsii, virulence

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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