Jurnal Fitopatologi Indonesia
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Identifikasi Molekuler Fitoplasma yang Berasosiasi dengan Tanaman Kaktus Hias Opuntia sp.
Cactus species (Opuntia sp.) is a popular ornamental succulent plant. Some ornamental cactus species in Indonesia showing proliferation and green mosaic pattern symptoms have been reported to be associated with phytoplasma infection. However, further molecular identification for accurate classification of the causal phytoplasma has not been done. This study aimed to diagnose phytoplasma associated with Opuntia sp. based on molecular methods involving PCR standard combined with nested-PCR, cloning and DNA sequencing. Standard PCR was carried out using P1/P7 primers followed by nested-PCR using R16F2n/R16R2 or fU5/rU3 primer pairs which amplify the 16S rRNA gene targets of 1.2 kb and 880 bp, respectively. Amplified fragment of nested-PCR using R16F2n/R16R2 primers was chosen to be cloned and sequenced for further identification and classification of phytoplasma. BLASTn analysis showed that the phytoplasma from Opuntia sp. was closely related to 16SrII group. Phylogenetic analysis and in silico RFLP indicated that phytoplasma strain infecting Opuntia sp. was a member of subgroup 16SrII-C (cactus witches’ broom phytoplasma). This is a newly report of cactus witches’ broom phytoplasma on Opuntia sp. in Indonesia.
Penyakit Busuk Akar dan Pangkal Batang Tebu di Sumatera Selatan
Root and basal stem rot disease caused by Xylaria sp. is a new diseases in Indonesian sugarcane plantation. The disease has been reported only occurred in sugarcane plantations in Sumatera. Limited information about the disease has slowed down disease diagnosis in the field. The research was aimed to describe symptoms, signs, and spatial distribution of the disease caused by Xylaria. A survey was conducted at a sugarcane plantation in South Sumatera (3° 26’ 16.6” S dan 104°40’ 09.8” E). Typical symptoms of the disease involved drying of all leaves and plant death, dry rot of root and basal stem, and retarded growth of ratoon cane were recorded. Stroma was found on surface of diseased stems and on soil surface of diseased plants, and spatial aggregation of diseased plants was observed in all locations. The distribution of the diseased plant aggregately and the presence of stroma on diseased plants are important characteristics of the disease diagnosis in sugarcane plantations
Penyakit Karat Bawang Daun yang Disebabkan oleh Puccinia allii Rud.
New disease of bunching onion (Allium fistulosum) with typical symptoms as rust disease was found in the sub-district of West Tompaso and Modoinding, District of South Minahasa, North Sulawesi in June 2016. Infected plants in the field showed yellowish brown pustules on leaf surface, followed by leaf yellowing and drying out started from the tip. Disease incidence in surveyed area reached 100% with disease severity between 30%–50%. Based on microscopic observation of the fungal morphological characteristic, i.e. uredium dan urediniospora, the causal agent was identified as Puccinia allii Rud
Dampak Penyakit Tanaman terhadap Pendapatan Petani Kubis-kubisan di Daerah Agropolitan Kabupaten Cianjur, Jawa Barat
Cruciferous vegetables are very important agricultural commodities for increasing farmers income. The main obstacles in their cultivation involved among others high level of pathogen infestation that may cause reduction in farmer’s income. This research was conducted to determine the main pathogens and their impact on farmer income in Agropolitan area of Cianjur Regency, West Java Province. The research was conducted through three activities, i.e. farmer survey, identification of the main pathogens, and measurement of disease intensity. The results showed that there were three main pathogens on assessed cruciferous vegetables, i.e. Alternaria brassiccicola (alternaria leaf spot), Plasmodiophora brassicae (clubroot), and Xanthomonas campestris (black rot), with disease intensity of 16.7%, 18.7%, and 15.1%, respectively. Clubroot disease was the most affecting disease in decreasing the production of cruciferous vegetables and the farmer income. Incidence of clubroot disease with an average disease intensity of 16.67% might lead to the decrease of farming income about 24%–28%
Deteksi Odontoglossum ringspot virus pada Anggrek Asli Koleksi Kebun Raya di Indonesia
Native orchid is one of Indonesian natural resources which play important role as parental materials in breeding program. Virus infection is one of the limiting factors in the cultivation of orchid. The purpose of this study was to detect Odontoglossum ringspot virus (ORSV) from native orchid. Symptomatic orchids were collected from 5 botanical gardens, i.e. Bogor, Cibodas, Purwodadi, Balikpapan, and Enrekang Botanical Gardens. Detection and identification was conducted by serological method using ORSV specific antisera, followed by RT-PCR and DNA sequencing. The serological test showed that 5 samples gave positive reaction against ORSV antiserum, i.e. Phalaenopsis amboinensis (KRB2) and Phalaenopsis amabilis (KRB12) from Bogor Botanical Garden, Phalaenopsis amabilis (KRP18) and Dendrobium salacence (KRP20) from Purwodadi Botanical Garden, dan Phalaenopsis modesta J. J. Sm. (KRBp5) from Balikpapan Botanical Garden. RT-PCR of the 5 samples using specific primer of ORSV coat protein gene was successfully amplified fragment DNA with size ± 474 bp. Homology analysis of those 5 ORSV isolates showed the highest index similiarity of 99.8% with corresponding sequences from 14 other ORSV isolates. Phylogenetic analysis indicated that ORSV KRB2 and KRP18 isolates was clustered in a separate group far from ORSV isolates in other countries. This is the first report of ORSV infection on native orchids collection from 5 botanical gardens in Indonesia
Keragaman Morfologi, Genetika, dan Patogenisitas Colletotrichum acutatum PenyebabAntraknosa Cabai di Jawa dan Sumatera
Colletotrichum acutatum is known as the major causal agents of anthracnose disease of chilli pepper in Indonesia. This research was aimed to study genetic variability of C. acutatum in Java and Sumatera based on morphological and molecular characteristics and to evaluate pathogenicity of several isolates. Observation on morphological characteristics involved colour and growth of each colony as well as shape and size of conidia. Molecular identification was performed by DNA amplification using specific primer for C. acutatum, i.e. CaInt2/ITS4 followed by sequencing and nucleotide sequence analysis. Pathogenicity test for each isolate on Capsicum annuum and C. frutescens was conducted in the laboratory using detached chilli. Morphology variability was observed from 40 isolates of C. acutatum. Most of the isolates have white/beige colonies with fusiform conidia of 6.11–9.73 µm in length and 2.24–2.73 µm in width. Pathogenicity of 3 C. acutatum isolates varies from moderate to high based on lesions size on infected chilli. Sequence analysis of 8 C. acutatum isolates indicated high homology among isolates from Java and Sumater
Kepekaan Erythricium salmonicolor Penyebab Penyakit Jamur Upas pada Kemiri Sunan terhadap Suhu, Cahaya, dan Fungisida
A typical pink disease symptom appeared on stem of Reutealis trisperma in Bogor. The present study was aimed for confirming the causal pathogen and testing its sensitivity to temperature, light and fungicides. The fungus was identified based on its morphological characteristics. The fungal inoculum was obtained by tissue isolation of infected stem bark. For pathogenicity test, the fungus was inoculated onto sterilized pieces of woody R. trisperma branch, then fastened on the seedlings and incubated in the green house. The effect of temperatures on fungal growth was tested by planting the fungal colony onto potato dextrose agar (PDA) then incubated at 25–34 °C. The sensitivity of the fungus to light was tested by inoculating the fungus into flask with potato dextrose broth (PDB) medium on a shaker (60 rpm) exposing it to white light tube (400 luks) or in a dark condition for 15 days at 25 °C. The obtained fungal colonies were weighed. Efficacy of copper hydroxide and mancozeb against the fungal colony growth was tested by inoculating the fungus onto PDA amended with 100, 200, 300, 400, and 500 ppm, respectively, of tested fungicides. The results showed that the causal pathogen was Erythricium salmonicolor. In the pathogenicity test, cobwebs of E. salmonicolor were formed on inoculated seedlings 3 weeks after inoculation. The optimum temperature for growth of E. salmonicolor was 28 °C. There was no significant effect of light on fungal growth. Mancozeb suppressed colony of E. salmonicolor growth better than copper hydroxide
Ketahanan Berbagai Kultivar Padi Lokal terhadap Penyakit Hawar Daun Bakteri
Bacterial leaf blight disease caused by Xanthomonas oryzae pv. oryzae is an important rice disease in Indonesia, including in South East Sulawesi. The use of resistant varieties is one of the effective and environmentally friendly control strategies to suppress the disease. This study aimed to determine the level of resistance of some local rice varieties of South and Southeast Sulawesi against Xanthomonas oryzae pv. oryzae pathotypes IV, VIII and X. The study was conducted in a screen house involving 3 bacterial pathotypes and 11 local rice cultivars. Shearing method was used for inoculation of bacteria to leaf on vegetative and generative phases. Disease incidences were measured 3 weeks after inoculation, and the data was further used to determine the level of resistance of the tested rice cultivars. The results showed that incubation period of the disease was longer on Kelaca cultivar compared to other cultivars. On vegetative phase, this cultivar showed moderate resistant to pathotypes IV and X, and highly resistant to patotype VIII, whereas on the generative phase it showed moderate resistant to pathotypes IV and VII, and highly resistant to pathotype X. Therefore, Kelaca cultivar can be recommended for endemic areas of leaf blight in South and Southeast Sulawes
Potensi Metabolit Sekunder Cendawan Endofit Tanaman Cabai sebagai Penghambat Fusarium sp. Patogen Asal Biji Secara in Vitro
Endophytic fungi was known as controlling agents to pathogenic fungi, including Fusarium oxysporum. This research was aimed to select endophytic fungi from pepper which produced secondary metabolites and have beneficial effect in controlling seed borne pathogen especially Fusarium sp. Four isolates was obtained, i.e. CECL 19, CECL 28, CECL 38, and CECL 40; and further examined in 3 media fermentation, i.e. yeast glucose broth, potato dextrose broth, and potato dextrose yeast broth. Metabolites of endophytic fungi was tested in vitro for its inhibition effect on the growth of Fusarium sp. The result showed that the type of fermentation medium was significantly determining the ability of endophytic fungi in inhibiting the growth of Fusarium sp. Medium PDA and DEC was determined as the best medium to optimize metabolite production of CECL 28 and CECL 18, respectively. Metabolite compound produced by CECL 28 has been effective to inhibited Fusarium sp
Metabolit Cendawan Endofit Tanaman Padi sebagai Alternatif Pengendalian Cendawan Patogen Terbawa Benih Padi
Infection of seed-borne fungi on rice (Oryza sativa) may affect rice production and becomes an important problem in Indonesia recently. This study aimed to evaluate the potential of fungal endophyte metabolites isolated from rice (Oryza sativa L.) to control seed-borne pathogenic fungi. Research activities involved isolation of endophytic fungi from rice, isolation of seed-borne fungi, and inhibition test of isolated endophytic fungal metabolites on seed-borne pathogenic fungi. The results showed that 3 isolates of endophytic fungi, i.e. LA6, LA11, and LA14 were potential producing antifungal metabolite. The metabolites of LA11 and LA14 isolates was able to reduce the growth of seed-borne pathogenic fungi between 18.33 and 47.28%