Judul: Inventarisasi predator kumbang ubi jalar, Cylas formicarius Fab. (Coleoptera:Curculionidae)
Abstrak: Cylas formicarius Fab. (KUJ) adalah hama ubi jalar yang paling penting. Usaha untuk mengembangkan teknik- teknik pengendalian hama tersebut secara hayati masih kurang dikembangkan. Salah satu agens pengendali hayati hama tersebut adalah predator. Penelitian ini bermaksud menginventarisasi predator imago KUJ di beberapa daerah penghasil ubi jalar di Jawa. Pengumpulan artropoda predator dilakukan dengan cara mengumpankan KUJ yang dikumpulkan di beberapa tempat (exposure method), dengan cara memikatnya mengunakan feromon kelamin sintetis. Untuk mengetahui atau menentu- kan peranan artropoda yang ditangkap terhadap KUJ, maka dilakukan uji pemangsaan. Artropoda yang berhasil dikumpulkan meliputi serangga dari famili Formicidae (Hymenoptera), Carabidae (Coleoptera) dan Forficulidae (Dermaptera), dan dua laba-laba (Araneida) dari famili Lycosidae dan Oxyopidae. Artropoda yang paling banyak mendatangi perangkap adalah serangga, yaitu semut. Semut Anoplolepis longipes Jerdon, Iridomyrmex anceps Mayr dan Pheidole sp. diketahui menyerang KUJ di lapang pada saat pengamatan. Artropoda lain yang ditemukan di sekitar perangkap tidak ada yang menyerang KUJ. Namun demikian, tidak ada artropoda yang memangsa KUJ pada uji pemangsaan dan tidak ada yang mempengaruhi peletakan telur serta kegiatan makan KUJ.
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Judul: Pengamatan populasi Cylas formicarius (Fabr.) (Coleoptera : Brentidae) pada pertanaman ubi jalar (Ipomoea batatas (L.) Lamb.) di Desa Cikarawang, Kecamatan Dramaga, Kabupaten Bogor, Jawa Barat
Abstrak: Ubi jalar merupakan salah satu komoditas pangan penting di Indonesia. Kendala yang dihadapi dalam usaha tani ubi jalar di antaranya adalah kerusakan yang disebabkan oleh hama Cylas formicarius (Fabr.), yang dapat menyebabkan cetakan di lapang dan tempat penyimpanan. Penelitian ini bertujuan untuk mengetahui awal serangan hama di lapang dan laju peningkatan populasinya. Pengamatan keberadaan hama dilakukan dengan menggunakan perangkap pit fall, pengamatan langsung dan pengamatan di laboratorium. Sampel perangkap pit fall sebanyak 1/2 dari jumlah guludan di lahan. Perangkap berupa gelas plastik di beri larutan formalin 0.04% sebanyak 1/3 bagian gelas. Pengamatan dilakukan setiap hari. Pengamatan langsung dilakukan setiap hari pada 49 unit sampel dengan mengamati keseluruhan bagian tanaman sampel di atas permukaan tanah dan daerah sekitarnya dengan radius 20 cm. Sejak minggu ke-15 setelah. tanam,umbi sampel di bawa ke laboratorium untuk di amati kemunculan imago C. formicarius. Pengamatan pemunculan imago dilakukan selama delapan minggu kemadian. Hasil pengamatan visual langsung ke tanaman dan perangkap pit fall sampai dengan 99 hari setelah tanam (hst), menunjukan imago yang berada di lahan sangat sedikit (3 imago di pit fall dan 6 imago di pengamatan langsung). Setelah umbi terbentuk, pengamatan kemunculan imago dari umbi menunjukan bahwa populasi hama meningkat tajam pada 127 hst dan mencapai puncak pada 148 hst.
Keyword: Cylas formicarius, Fit fall, Ubi jalar

Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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