Judul: Isolasi Trichoderma spp. asal tanah dan aktivitas penghambatannya terhadap pertumbuhan Phytopthora capsici penyebab penyakit busuk pangkal batang lada
Abstrak: Lada merupakan tanaman rempah yang memberikan kontribusi terhadap devisa negara. Serangan Phytophthora capsici pada pangkal batang tanaman lada merupakan faktor utama menurunnya produksi lada Indonesia. Pengendalian hayati yang telah dikembangkan ialah pemanfaatan cendawan antagonis Trichoderma spp. Tujuan penelitian ini ialah mengisolasi, mengidentifikasi Trichoderma asal tanah perakaran lada dan menguji kemampuan penghambatannya terhadap pertumbuhan koloni P. capsici. Contoh tanah diambil dari tiga lokasi pertanaman lada, yaitu Bogor, Sukabumi, dan Bangka. Isolasi Trichoderma dilakukan dengan metode pengenceran serial dan pemurniannya menggunakan teknik spora tunggal. Uji aktivitas penghambatan Trichoderma terhadap P. capsici LP46 dilakukan dengan metode uji berpasangan pada media agar-agar kentang dektrosa. Sebanyak 49 isolat Trichoderma diperoleh dari contoh tanah. Semua isolat dapat menghambat pertumbuhan koloni P. capsici dengan kisaran hambatan 55-67%. Selanjutnya dipilih tiga belas isolat untuk dipasangkan dengan P. capsici LP46. Sebagai kontrol digunakan T. harzianum TSM. Semua isolat memiliki nilai persentase penghambatan yang tidak berbeda nyata dengan T. harzianum TSM. Mekanisme penghambatan Trichoderma diuji mengikuti metode Aryantha dan Guest dan mekanisme yang terlihat berupa pembelitan hifa. Lima isolat Trichoderma yang berhasil diidentifikasi ialah T. atroviride PC5, T. harzianum LBb5 dan LBC4, serta T. koningii PB20 dan S8.
Keyword: Inhibitor activity, Piper nigrum, harzianum TSM

Judul: Pengendalian penyakit busuk pangkal batang (Phytophthora capsici LEONIAN) pada lada (Piper nigrum L.) dengan ekstrak pinang, gambir, sirih, dan kapur sirih
Abstrak: Lada merupakan komoditas ekspor penting penghasil devisa Indonesia. Faktor pembatas produksi di antaranya patogen Phytophthora capsici penyebab penyakit busuk pangkal batang (BPB). Penelitian ini bertujuan mengetahui keefektifan ekstrak pinang, gambir, sirih, dan kapur sirih sebagai bahan pengendali penyakit BPB. Penelitian secara in vitro disusun dalam rancangan acak lengkap dua faktor dengan faktor pertama jenis ekstrak dan faktor kedua konsentrasi ekstrak. Isolat P. capsici berumur 4 hari dan berdiameter 5 mm ditumbuhkan pada media V8 yang sebelumnya telah dicampur dengan ekstrak uji. Perlakuan yang diuji yaitu ekstrak pinang 0,01%; 0,02%; dan 0,04%, gambir 0,01%; 0,02%; dan 0,04%, pinang + gambir 0,005%; 0,01%; dan 0,02%, campuran pinang + gambir + sirih + kapur sirih 0,0025%; 0,005%; dan 0,01%, ditambah kontrol (tanpa perlakuan ekstrak). Setiap perlakuan diulang 3 kali. Pengamatan dilakukan selama 6 hari dengan peubah yang diamati yaitu perkembangan diameter miselium terhadap waktu inkubasi. Pengujian secara in vivo disusun dalam rancangan acak lengkap dengan 5 ulangan dan 4 unit perlakuan. Pengujian dilakukan dengan mencelupkan daun lada pada ekstrak uji, kemudian diteteskan sebanyak 0,1 ml zoospora P. capsici 9 x 104 sel/ml pada 4 titik di bawah permukaan daun. Perlakuan yang diuji yaitu ekstrak campuran pinang + gambir + sirih + kapur sirih 0,005%; ekstrak campuran pinang + gambir + sirih + kapur sirih 0,01%; ekstrak pinang 0,04%; fungisida berbahan aktif propineb 70% konsentrasi 0,2%; dan kontrol. Pengamatan dilakukan selama 11 hari dengan peubah yang diamati yaitu kemunculan dan perkembangan diameter gejala terhadap waktu inkubasi. Ekstrak campuran pinang + gambir + sirih + kapur sirih 0,005%; campuran ekstrak pinang + gambir + sirih + kapur sirih 0,01%; dan pinang 0,04% secara in vitro cukup efektif menghambat perkembangan diameter koloni P. capsici. Selain itu, ekstrak campuran pinang + gambir + sirih + kapur sirih 0,01% secara in vivo efektif dalam menghambat keparahan penyakit dan memiliki daya efikasi yang menyamai daya efikasi fungisida propineb 0,2%.
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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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