Judul: Pengujian Laboratoris Efikasi Larutan Kitosan terhadap Rayap Tanah Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae)
Abstrak: Subterranean termite Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae) has been known as the most important structural pest that causes significant economic losses on building in Indonesia. Up to now termite control techniques that have been applied are wood preservation and soil treatment, both of the techniques could causing environment pollution. Meanwhile chitosan is known as natural polymer that potentially could developed as wood preservative due to its bioactive compound. A laboratory study was conducted to evaluate the efficacy of chitosan in three concentration levels (0.5%, 0.75%, and 1%) against subterranean termite C. curvignathus. Chitosan was dissolved in 1% acetatic acid solution then applied to wood samples made from pine board 10 cm x 8 cm x 2 cm with cold soaking treatment for three days. Wood samples were exposed to subterranean termite C. curvignathus for three weeks based on PSIH-IPB-1998 standard method. Retention of chitosan solution, termite mortality, and degree of protection of wood samples were determined. The results showed that concentration of chitosan solution affect the retention, termite mortality, and degree of protection of wood samples. Wood samples at 1 % concentration were promoted 3.50 kg/m3 retention and caused 98.17% termite mortality with maximum degree of protection of wood samples against C. curvignathus. Chitosan could develop as a wood preservative, especially for protection of wood products that are not directly exposed to weather. However further studies are needed to determine leachibility, mode of action, as well as optimum dose of chitosan solution.
Keyword: wood preservation, Coptotermes curvignathus, Chitosan

Judul: Efikasi Nematoda Entomopatogen Heterorhabditis sp. dan Steinernema sp. Isolat Bogor Sebagai Bioinsektisida Terhadap Rayap Tanah Coptothermes curvignathus Holmgren (Isoptera : Rhinotermitidae)
Abstrak: The subterranean termite, Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae) is the most important wood destroying termites in many regions in Indonesia. Their infestation on buildings, agricultural crops, and forest trees has caused significant economic loses. Meanwhile termite control technology still depend on termiticide application, which cause negative effect to environment. On the other hand, entomopathogenic nematodes is one of agents potential bio-control in controlling subterranean termites without negative effect to environment. A research was conducted to evaluate the effectiveness of the entomopathogenic nematodes Heterorhabditis sp and Steinernema sp as a biological control agents against subterranean termites Coptotermes curvignathus Holmgren in field test. Procedures of the research included the rearing of the entomopathogenic nematodes, both in-vivo and in-vitro, the evaluation of the nematodes toxicity against subterranean termites (LC50 and LT50) and field evaluation of entomopahogenic nematodes against subterranean termite at field. The mortality of termites was analysis with Completed Randomized Design and Tukey's Test. The effective deusity 600 IJ/ml of entomopathogenic nematodes Heterorhabditis sp and Steinernema sp caused 100% mortality of subterranean termites C. curvignathus. The LC50 value for the population of subterranean termites C. curvignathus for Steinernema sp was 322 IJ/ml and Heterorhabditis sp was 355 IJ/ml. The LT50 value for the population of subterranean termites C. curvignathus was 33,94 hours for Steinernema sp and was 34,90 hours Heterorhabditis sp. For the efficacy test, the mortality value of subterranean termites C. curvignathus caused by Steinernema sp and Heterorhabditis sp were 90,23 % and 85,65 % respectively. In field testing the mortality value of subterranean termites C. curvignathus caused by Steinernema sp and Heterorhabditis sp were 79,51 % and 94,40 % respectively. It is conclued that Steinernema sp and Heterorhabditis sp can be used as biological control against C. curvignathus.
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Judul: Analysis of M/G/1 Queue Model with Two Phases of Service and Bernoulli Feedback System
Abstrak: Model antrean M/G/1 dengan sistem feedback Bernoulli adalah model antrean dengan proses kedatangan mengikuti proses Poisson. Pada karya ilmiah ini dibahas sistem antrean M/G/1 dengan dua fase layanan. Setelah layanan pertama selesai, pelanggan dapat memilih untuk meninggalkan sistem dengan peluang ... dst, The M/G/1 queueing model with the Bernoulli feedback system is a queueing model with the arrival process following the Poisson process. In this manuscript M/G/1 queueing system with two phases of service is discussed. After the first service is completed, the customer can choose to leave the system with probability ... dst
Keyword: queue, Bernoulli, probability generating function, expected value