Judul: Eksplorasi Bakteri Lisis sebagai Agens Pengendalian Hayati Penyakit Akar Putih (Rigidoporus lignosus (Kloztch) Imazeki) pada Tanaman Karet.
Abstrak: The hevea rubber (Hevea brasiliensis) is one of the important commodity in Indonesia for export purposes. One of the obstacles to be limiting in the production of hevea rubber is white root fungus disease caused by Rigidoporus lignosus. The purpose of this study was to explore and select a lysis bacteria from hevea rubber rhizosphere which have the potential as biological control agent of the disease. This research had been conducted in laboratory Wish, Dramaga, Bogor and laboratory Mycology, Departement of plant protection, faculty of agriculture, IPB on December 2014 until March 2015. Of the 251 isolates obtained in this study, 118 isolates on has the ability as cellulolytic, 68 isolates are cellulolytic and chitinolytic, and 65 isolates did have both of these properties. Out of the isolates that have lysis properties, 147 (79%) were not pathogenic based on the hypersensitivity test in tobacco plants. Among of those non-pathogenic isolates, 30 isolates could inhibit the radial growth R. lignosus in vitro testing. Based one the score of lysis index, inhibition zone, and growth inhibition, 13 isolates might be potential as biological control agents of R. lignosus.
Keyword: antagonis, kitinolitik, selulolitik, Rigidoporus lignosus

Judul: Potensi Trichoderma harzianum dan Mikoriza untuk Pengendalian Penyakit Jamur Akar Putih (Rigidoporus lignosus (Kloztch) Imazeki) pada Karet.
Abstrak: Indonesia is the largest producer of rubber after Thailand. The development of the rubber industry is still on going. However, the presence of rubber diseases become a problem in the rubber industry development. White root fungus disease caused by the fungus Rigidoporus lignosus is a major disease in rubber plantations. The experiment aims to determine the potential of the fungus Trichoderma harzianum and mycorrhizae fungi for controlling white root disease on rubber seedlings in the greenhouse. The experiment has been done in complete randomizeddesign, 8 treatments and 4 replications. The treatments were, applications of T. harzianum, mycorrhizae, and their combinations, with and without R. lignosus. The result have shown that T. harzianum, mycorrhizae, and their combinations have supressed JAP diseases incidence and severity. At the time of seedlings, the treatment of T. harzianum singly has found as the most effective and efficient in supressing diseases severity and in increasing plant vegetative growth.
Keyword: mycorrhiza, Rigidoporus lignosus, rubber, Trichoderma harzianum

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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