POTENSI BAKTERI ANTAGONIS DALAM MENEKAN PERKEMBANGAN PENYAKIT LAYU BAKTERI JAHE

<p><strong>Potency of antagonist bacteria in inhibiting the bacterial wilt disease progress ginger</strong></p><p>Bacterial wilt disease caused by Pseudomonas solanacearum is an important disease in ginger plant (Zingiber oicinale Rose.) in Indonesia. The objective of this research was to study the effectiveness of biological agents in inhibiting the progess of bacterial wilt on ginger. The research was conducted at the geenhouse of Research Institute for Spice and Medicinal Crops in 1997-1998 then was followed with a ield experiment at Sukamulya Experimental Garden in 1998/1999. At the greenhouse experiment seven kinds of antagonists bacteria were formulated either individually or combination. Pseudomonas fluorescens (PF), P. cepacia (PC) and Bacillus sp. (BC), mixtue of PF + PC, mixtue of PC + BC, mixture of PF + BC, and mixtue of PF + PC + BC were tested in the geenhouse on ginger plant cultivars putih besar grown in the pot containing soil formerly used for growing P. solanacearum infected tomato. I he results of this experiment indicated that the combination of PF+PC+BC significantly suppressed the progress of bacterial wilt disease compaed to control and other tested combination. In the ield experiment carried out at the bacterial wilt disease endemic area the combinations of PF+PC+BC, Trichoderma harzianum (Bit-1) and combination of PF+PC+BC+BII-I were tested with two levels of application, i.e. two applications with two months interval and 4 application with one month interval. The results showed that the application of antagonists bacteria inhibited Ihe bacterial wilt disease progress and signiicantly increased ginger rhizome yield. The yield of the rhizome from the plants teated with different intervals were not different. However, the application of the antagonist bacteria were not able to eradicate ginger infection by Pseudomonas solanacearum thoroughly.</p>

Aplikasi Senyawa Aktif Bakteri Endofit Potensial dan Pupuk Terhadap Penyakit Layu Daun, Busuk Buah Pada Tanaman Tomat

Tujuan penelitian ini adalah untuk mengetahui pengaruh aplikasi bakteri endofit potensial dan pupuk terhadap penyakit layu daun dan busuk buah oleh bakteri Pseudomonas solanacearum. Dua bakteri endofit terseleksi (HL.39B.86 dan HL. 39B.88) digunakan dalam penelitian ini untuk diaplikasikan pada tanaman tomat. Proses fermentasi dilakukan dalam 2 macam medium cair untuk mencari pola pertumbuhan yang maksimal. Percobaan dilakukan dalam 2 unit percobaan. Percobaan I.Menguji 10 isolat bakteri endofit terhadap serangan penyakit layu pada tanaman tomat dan cabe, percobaan II.Mengaplikasi senyawa aktif bakteri potensial terhadap penyakit layu dan busuk buah pada tanaman tomat Hasil analisis KLT menunjukkan bahwa kedua bakteri tersebut menghasilkan senyawa aktif, dengan melihat noda (spot) pada kertas KLT. Hasil penelitian menunjukkan bahwa bakteri endofit HL.39B.86 dan HL. 39B.88 mampu menahan dan memproteksi serangan penyakit layu dari bakteri P. Solanacearum pada tanaman tomat. Pemberian pupuk N dan K nyata meningkatkan bobot buah tomat, tetapi tidak nyata meningkatkan bobot biomas, tinggi tanaman, dan lebar kanopi tomat.

Aislamiento de agentes supresores a Pseudomonas solanacearum E.F. Smith en tomate (Lycopersicon esculentum).

Three soil samples were collected at the highlands of Cartago (Cipreses, Pacayas and Tierra Blanca) Costa Rica and were placed in individual trays. Then, 50 seeds of tomato variety Hayslip were sown in each tray. After 40 days, plants were inoculated with a Pseudomonas solanacearum. Two weeks after the inoculation, healthy and diseased plants were incorporated and left to decompose for 12 days, in order to allow establishment of the bacteria in the soil. Then, 70 seeds were sown in each tray. After 42 days, plants were inoculated by inundation with a suspension of 103 CFU/ml of P. solanacearum. Surviving plants were taken to the laboratory and desinfected; cuts were made at the base of the stems, then the epidermis was removed and cuts were placed in test tubes containing sterile water for 90 minutes. The Petri dishes were then incubated for 48 hours at 28°C. From the growing bacteria, antagonism on P. solanacearum was evaluated by scratching Pctri dishes with each bacteria over same medium alrealy dcseribcd. Out of 22 bacteria originally obtained, 12 showed antagonism on P. solanacearum. Antibiotic substances might be involved in this process.

RESISTENCIA DE LOS CULTIVARES DE PAPA MOLINERA Y AMAPOLA A Pseudomonas solanacearum

La marchitez bacteriana de la papa, causada por Pseudomonassolanacearum E. F. Smith, afectó severamente al cultivar de papaMolinera en un campo ubicado en la provincia de Cajabamba,departamento de Cajamarca. Para determinar si el ataque al cultivarse debía a la pérdida de su resistencia a P. solanacearum o a laaparición de nuevas variantes de la bacteria, se colectaron muestrasde plantas de papa con síntomas de marchitez. En el diagnóstico sedeterminó que de ocho cepas aisladas, siete correspondieron al(Biovar) Bv II y una al Bv I. En las pruebas de patogenicidad conestas cepas en el cultivar susceptible Revolución, se observó que lacepa del Bv I fue muy poco agresiva. Cuatro cepas aisladasrecientemente (197, 199, 201 y 204) y dos antiguas (012 y 050) dela colección del Centro Internacional de la Papa, seleccionadascomo las más agresivas, fueron inoculadas en plantas de papa de loscultivares Molinera, Amapola y Revolución. Amapola presentó unnivel de resistencia similar al de Molinera y su cultivo puede serrecomendado en zonas afectadas por P. solanacearum. Se comparóasimismo, el grado de patogenicidad de las seis cepas seleccionadashabiéndose determinado que a temperatura alta (26-32°C), todasocasionaron síntomas de marchitez, en las plantas inoculadas. Atemperatura baja (15-26°C) solamente dos (109 y 204) manteníansu agresividad aunque en menor grado que a temperatura alta. Doscepas (199 y 201) incitaron un grado sumamente bajo de marchitez.La cepa 050 de comportamiento altamente agresivo a temperaturaalta no ocasionó marchitez a temperatura baja. Estos resultadosindican la existencia de una gran diversidad de variantes de labacteria las mismas que pueden o no ejercer su acción patogénicaen relación con la temperatura existente.

Bakteri Patogen Tumbuhan

Penyakit tumbuhan sangat berperanan dalam kaitannya dengan ketersediaan pangan. Diantara agens utama yang menyebabkan terjadinya penyakit pada tanaman yang mempunyai nilai ekonomis, diketahui bahwa fungsi patogen merupakan agens penyebab penyakit yang paling penting. Namun demikian, penyakit yang disebabkan oleh bakteri patogen tumbuhan ternyata juga dapat menimbulkan kerugian yang tidak kalah pentingnya bila dibandingkan dengan penyakit yang disebabkan oleh cendawan patogen, khususnya yang disebabkan oleh Ralstonia (Pseudomonas) solanacearum yang merupakan contoh yang nyata tentang potensi kerusakan yang ditimbulkan oleh bakteri fitopatogen.

PERTUMBUHAN BAKTERI Pseudomonas solanacearum E.F. Smith PADA PEMBERIAN EKSTRAK URANG ARING

ABSTRACT Pseudomonas solanacearum is a bacterium that causes wilt disease in tomato, peppers, tobacco, potatoes and Solanaceae plants in general. The bacteria attacks their hosts in nearly all phases of development. Young plants are usually more vulnerable and the bacteria tends to grow faster. The use of synthetic pesticides for controlling the disease could cause many negative impact on human and environment, Hence, it is necessary to find an environmentally friendly pesticides for controlling the disease. Urang aring (Eclipta alba L. Hask.) contains bioactive compounds that potential to be used as botanical pesticides. This research was conducted to evaluate the effect of ethanol extracts of urang aring (Eclipta alba L. Hask.) to inhibit the growth of Pseudomonas solanacearum. Bioassay was done by deluting extracts to make concentration 1%, 2%, 3%, 4% (w/v). The result showed that ethanol extracts inhibited the growth of P. solanacearum starting at concentration 1% with inhibition zone diameter 10,7 mm. At level 4% concentration (inhibition zone diameter 17.59 mm) were not significant difference with agrmicyn 0.03%, a synthetical bactericidal with inhibition zone diameter 18,31 cm. The results of this study revealed that urang aring was potential as botanical pesticide. Keywords: Urang Aring, Eclipta alba, Pseudomonas solanacearum