Judul: Monitoring Serangan Hyblaea puera Cramer Pada Tanaman
Abstrak: INTRODUCTION. Jati Unggul Nusantara (JUN) is a type of teak trees which is developed from Perhutani Superior Teak (JPP) and is developed further and produced by PT Setyamitra Bhaktipersada and Cooperative of Perumahan Wanabakti Nusantara. Plantation of teak trees often faces the problem of attack by pest. One of the pests which attack teak plantation is Hyblaea puera Cr, which often severely defoliates teak plantation in the beginning of rainy season. According to information the JUN planted by the Cooperative of Perumahan Wanabakti Nusantara (KPWN), is currently attacked by H. puera. The extent of infestation and the development of this pest on JUN plantation owned by KPWN has not been known. Therefore, monitoring of the infestation of H.puera on this plantationis badly needed. MATERIALS AND METHOD. This research comprised the activities of determining observation plots; labeling of trees; and field observation in each plot which include measurement of tree height and diameter, counting the number of trees attacked by H. puera every 2 weeks, counting the total number of leaves and number of young leaves attacked by H.puera in each tree, counting the number of larvae of H. puera present in each tree in each observation plot, and observing other pests occurring in each observation plot. RESULTS AND DISCUSSION. Research results showed that percentage of occurrence of H. puera attack was increasing during the observation period. The highest occurrence at the last observation, 9 October 2008, namely as much as 93.1 %. Intensity of infestation showed fluctuation, with ranged of 12.2 to 12.6 %. Number of H.puera larvae per tree during observation period fluctuated from 0.08 to 1.30 individuals. Number of larvae per 0.1 ha fluctuated from 4.75 to 64.5 individuals. Attack by H.puera during observation did not significantly affect the height and girth of teak stems. Other pests found in this study, beside H. puera were Xyleutus sp, Agrius sp, and white grub of Lepidiota stigma. These pests were considered as being not dangerous yet (insignificant). CONCLUSION. Percentage of occurence by H. puera exhibited increase with time, and intensity of infestation fluctuated from time to time. Number of larvae per tree and per hectare exhibited fluctuation which was due probably to environmental condition, particularly the existence of young leaves which constituted the insect’s food, that could affect the life of H.puera. Attack by H. puera during the observation, did not affect height and girth of teak stems.
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Judul: Serangan Uret Dan Cara Pengendaliannya Pada Tanaman Eucalyptus Hybrid Di Hutan Tanaman Pt. Toba Pulp Lestari Sektor Aek Na Uli Sumatera Utara
Abstrak: PT Toba Pulp Lestari Tbk is one of the companies which undertake the business of Industrial Plantation Forest (HTI) in Sumatra Utara Province. The objective of the undertaking was producing pulp wood for paper raw materials. The developed plant species was Eucalyptus spp which constituted a fast growing species. According to information from PT Toba Pulp Lestari, one kind of pest which often attacks Eucalyptus spp was insect grub. The attack by this grub often occurs in Sector of Aek Na Uli. This grub attacks roots of plants which are 1- 3 months old, and up to now this problem has not been able to be controlled yet. The objectives of this research were determining the kinds of grub which attacked Eucalyptus in the HTI area of Toba Pulp Lestari in Aek Na Uli sector, determining the effect of attack and the extent of loss created by the grub attack, learning the controlling technique practiced by the company, and learning the effectiveness of insecticide for controlling the grub. edit. This research was conducted in 2 months old Eucalyptus hybrid plants in compartment D 095 with area size of 5.8 ha in Aek Nauli sector, the province of North Sumatra, from 1 April through 20 May 2008. Equipments used in this study were 25 m plastic rope, 14 m plastic rope, compass, wooden pegs, digital camera, and insect collection bottles. Materials used in this study were Karbofuran 3-G and formalin 2 %. Research procedure comprised the counting of the number of eucalypt trees existing in the measurement plot, counting the number of eucalypt trees which were attacked by the grub, examining the tree condition which suffered attack from the grub (wilting, drying, dying), and collecting the various kinds of attacking grubs for identification purpose. Research results showed that percentage of grub growth in each plot was 90.67 % on the average. Species of grub which attacked eucalypt trees in compartment D 095 were Leucopholis rorida, Lepiodata stigma, and Euchlora viridis. On the basis of attack percentage in each measurement plot, the grub attack on Eucalyptus hybrid was categorized as nearly uniform in all compartments. Percentage of plants which suffered attack by grub in compartment D 095 reached 18 % or around 240 trees per hectare. The material loss due to attack by grub in compartment D 095 Rp 189.976,8. Control action conducted in the field to overcome the attack by this grub was by replanting of failures. The use of Karbofuran 3 – G with dosage of 10 gram / planting hole was effective enough to control the grub attack. Key words: PT Toba Pulp Lestari, grub, Eucalyptus hybrid, compartment, Karbofuradan 3-G.
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Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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