Virulensi Wereng Batang Cokelat (Nilaparvata Lugens Stål) dan Strategi Pengelolaannya

Wereng batang cokelat (WBC) timbul menjadi hama utama padi di Asia sebagai dampak revolusi hijau. Ledakan populasi WBC didukung oleh perilaku WBC yang monofagus pada padi, keperidian tinggi, dan kemampuan migrasi jarak jauh. WBC bersifat labil dalam virulensi dan mampu beradaptasi pada varietas tahan. Penggunaan istilah ‘biotipe' untuk pengelompokan virulensi WBC masih diperdebatkan karena adanya variasi virulensi dan genetik antarindividu dalam satu biotipe. Makalah tinjauan ini membahas aspek strategi hidup dan makan, biokimia, interaksi dengan endosimbion, dan genetik WBC untuk mengetahui basis adaptasi virulensi WBC sehingga dapat digunakan dalam perbaikan strategi pengelolaan hama ini. Pada level molekuler, virulensi ditandai dengan peningkatan profil ekspresi gen-gen yang berkaitan dengan detoksifikasi senyawa alelokemik tanaman; metabolisme lipid, karbohidrat, asam amino, dan nitrogen; jalur lintas penyinalan respons pertahanan, respons terhadap cekaman, dan respons kekebalan. Penelitian genomik mengungkap interaksi komplementer antara WBC dan mikroorganisme endosimbion, tetapi percobaan menggunakan WBC aposimbiotik menunjukkan bahwa kepadatan endosimbion tidak selalu berkorelasi positif dengan virulensi WBC. Bertolak belakang dengan hasil-hasil penelitian sebelum-nya, pemetaan genetik gen virulensi menggunakan tetua inbred menunjukkan bahwa virulensi WBC dikendalikan secara monogenik sehingga hubungan gene-for-gene antara WBC dengan tanaman padi berlaku. Strategi penanaman varietas tahan untuk mengantisipasi adaptasi virulensi WBC seiring dengan dinamika varietas padi yang ditanam di lapangan dibahas dalam makalah ini

Pembiakan Nematoda Patogen Serangga (Rhabditida: Heterorhabditis Dan Steinernema) Pada Media Semi Padat

Field application of entomopathogenic nematodes (EPN) is still hampered by inefficient mass production. The aim of this study was to compare three published in vitro media (medium Wouts, Bedding and Han) for mass propagation of three indigenous EPNs (Heterorhabditis indicus PLR2, H. indicus isolate 5, and Steinernema T96) and one commercial strain (S. carpocapsae #25). The media were impregnated in shredded polyurethane sponge, pre-inoculated with symbiotic bacteria of each nematode and inoculated with the respective infective juveniles (Ijs) of the nematode. Nematode yields at three weeks after nematode inoculation were inconsistent accross replications and experiments and generally not significantly influenced by the kind of media tested. Average yields showed that the highest IJ productions were obtained on medium Han for H. indicus PLR2 (0,4×105 Ijs/g medium) and for S. carpocapsae #25 (2.2×105 IJs/g medium), and on medium Wouts for H. indicus isolate 5 (6.5×105 Ijs/g medium) and Steinernema T96 (1.5×105 IJs/g medium). The Ijs\u27 body were significantly shorter than those of in vivo propagated, which may impair the nematode pathogenicity. Modifications of the propagation technique and media formulation are needed to improve the quantity and quality of Ijs

Aplikasi Teori Perilaku Manajemen pada Bank Milik Pemerintah di Indonesia

This paper analyzed the behavior management in state owned bank in Indonesia. The behavior management, which is divided into four hypothesis which are, bad management, bad luck, skimping and moral hazard. This hypothesis is tested using four variables, which are efficiency, non-performing loan and capital adequacy ratio. Meanwhile, the Granger Causality test is using to find out which behavior management is happened. This concept then applied in ordinary least square model. As modification, this research use VAR (Vector Autoregressive). Since VAR also using granger causality basic concept. The result show that bad luck hypothesis happened. This is similar with the condition in India, Nordic, Central and Eastern Europe

Pathogenicity of Entomopathogenic Nematode on Sugarcane White Grub Lepidiota Stigma (Coleoptera: Scarabaeidae)

Sugarcane (Saccharum officinarum) is one of high-value commodities in Indonesia for producing sugar. Sugarcane production recently reduced due to insect pests attacked, mainly white grub Lepidiota stigma (Coleoptera: Scarabaeidae). Utilization of entomopathogenic nematodes (EPN) is one of the alternative control methods for sugarcane white grub. The aim of the presentstudy was to select the higher pathogenicity of EPN isolates for controlling the sugarcane insect pest. The study was conducted in Insect Pathology Laboratory of Indonesia Sweeteners and Fiber Crops Research Institute. Nine isolates of EPN, e.g. DKS-1, AGH-1, DKH-1, DKH-5, NH-1, NH-2, PH-1, PH-2, and PH-4 and one untreated control were tested for their pathogenicity against sugarcane white grub, L. stigma. Each treatment was arranged in Completely Randomized Design with three replications. Every treatment consisted of 30 individuals of the third instar of white grub which treated by 2 × 104 infective juvenile or IJ of EPNisolates. Parameter observed was the mortality of sugarcane white grub, L. stigma. The result showed that all of EPN isolates tested were promising pathogenic against the white grub with about 10 to 80% of the average percentage of mortality. However, DKS-1 and PH-1 showed more pathogenic against L. stigma with about 80–90% and 70–80% of white grub mortality,respectively. The highest enhancement of white grub mortality occurred at 72 hours after treatment and it was showed by DKS-1 and PH-1 isolates which increased the percentage of white grub mortality about 57.1 and 50%, respectively. Obtaining the promising isolates of NPS with different host seeking strategies will potentially increase the effectivity of control against whitegrub with the result to increase the yield of sugarcane

Perbanyakan Nematoda Patogenik Serangga (Rhabditida: Steinernema Dan Heterorhabditis) Pada Media in Vitro Cair Statik

Entomopathogenic nematodes belongingto genera Steinernema and Heterorhabditis are potentiallymost effective and safe biological control agents for insectpests, especially for soil dwelling insects and those living incryptic habitats. Field application of the nematodes is stillhampered by supply of large number of infective juvenile(IJ) nematodes. Five published in vitro media along with itstwo modifications were tested for mass propagations of twoindigenous nematodes (H. indicus PLR2 and SteinernemaT96) and one commercial strain (S. carpocapsae #25).Varying levels of IJ yields were observed across thereplications and experiments. Medium F that contained 1.0%yeast extract, 2.5% egg yolk, and 4.0% soy oil yielded thehighest IJ numbers of H. indicus PLR2 (1.5×105 IJ ml-1) andof S. carpocapsae #25 (2.9×105 IJ ml-1), whereas the widelyused medium B, which is based on homogenized chickenoffal (40%), yielded the highest number of Steinernema T96(5.8×104 IJ ml-1). The IJ's quality, as measured by theirmorphometrics and pathogenicities, were generallyimpaired, indicating the lack of essential nutrient(s) in themedia. Optimization of the propagation media is thereforestill needed to increase IJ's quantity and quality to achievethe required standard for commercial scale of artificialpropagation

Pengembangan Set Multipleks Penanda DNA Mikrosatelit Untuk Analisis Variasi Genetik Padi Dan Kedelai

Detection of multiplex microsatellite markers in asingle capillary array on a laser detection system is traditionallyconducted with specific primers that are labelled withfluorescent dyes. An alternative method using fluorescentlabels that are appended to 5\u27 end of universal primer M13instead of to the specific primers offers flexibility indesignning multiplex panels and a less expensive method.Allele size range of microsatellite loci that can be grouped inmultiplex panels can be accurately estimated by pooling andanalyzing DNA samples from several genotypes simultaneously.This paper describes the procedure in developmentof microsatellite multiplex panels using M13 fluorescentlylabelledand estimation of allele size range based on pooledDNA strategies. Two multiplex panels of PCR amplificationproducts for rice consisting of 15 loci and three panels forsoybean consisting of 10 loci have been designed. Thepanels have been applied to 50 accessions of rice and soybeanwith fairly good results. Further characterization ofallele size range, however, is required prior to the applicationof these panels to diverse genotypes. The proceduredescribed here should be applicable in the development ofmultiplex panels of other species