Penapisan Jamur Penghasil Senyawa Antimikroba Dari Tanah Bangka Dan Taman Wisata Alam Sibolangit Serta Potensinya Menghambat Pertumbuhan Beberapa Jamur Patogen Tanaman

Kajian tentang penapisan jamur tanah penghasil senyawa antimikroba yang diisolasi dari Bangka dan Taman Wisata Alam Sibolangit dan kemampuannya menghambat pertumbuhan jamur penyakit tanaman telah dilakukan. Tiga puluh isolat jamur diisolasi dari tanah menggunakan agar dektrosa kentang. Jamur yang ditemukan termasuk genus Penicillium, Aspergillus, Fusarium, Curvularia, Rhizomucor, Paecilomyces, Moniliella, Eupenicillium, dan Trichoderma, dan empat jamur tidak dapat diidentifikasi yaitu sp.1, sp.2, sp.3, dan sp.4. Jamur yang paling sering ditemukan dari genus Aspergillus dan Penicillium. Empatbelas isolat berpotensi menghambat pertumbuhan pertumbuhan Ganoderma boninense dan Fusarium oxysporum. Tidak ada isolat yang mampu menghambat pertumbuhan Penicillium citrinum. Ekstrak methanol Penicillium sp.1 menunjukkan kemampuan terbesar dalam menghambat pertumbuhan G. Boninense, sedangkan Penicillium sp.8 menghambat pertumbuhan F. oxysporum

Penghambatan Serangan Sclerotium Rolfsii Penyebab Rebah Kecambah pada Kedelai dengan Bakteri Kitinolitik

The inhibition of Sclerotium rolfsii as causal agent of soybean damping off by using chitinolytic bacteria were studied in Laboratory of Observation Pest and Disease UPT-BPTPH 1 and Laboratory of Microbiology, Department of Biology, Faculty of Mathematics and Natural Sciences, University of Sumatera Utara, Medan. The aim of this research was to investigate the ability of chitinolytic bacteria to inhibit the growth of S. rolfsii. Six isolates of chitinolytic bacteria were used in this study. The inhibition zone between colony of the bacteria and the fungus was measured. The result showed that the bacterial isolates has different ability in inhibiting the growth of S. rolfsii. Enterobacter sp. BK15 and Bacillus sp. BK13 were the most effective in inhibiting the growth of S. rolfsii with inhibition zone of 3.70 cm and 3.75 cm, respectively. The less effective was shown by Enterobacter sp. PB17 with inhibition zone of 0.10 cm, while Enterobacter cloacae LK08 have no ability to inhibit S. rolfsii. The seeds soaked in bacterial suspension by Bacillus sp. BK13 dan Enterobacter sp. BK15 were able to reduce damping off by 44.4% and 50%, respectively

Penghambatan Pertumbuhan Aspergillus Flavus Dan Fusarium Moniliforme Oleh Ekstrak Seruni (Wedelia Biflora) Dan Kembang Bulan (Tithonia Diversifolia)

The growth inhibition of Aspergillus flavus and Fusarium moniliforme by extract of seruni (Wedelia biflora) and Kembang bulan (Tithonia diversifolia) has studied. Kirby-Bauer disc diffusion were used in this experiment. The leaf methanolic extracts prepared were 0, 5, 10, 15, 30, 40, 50, 60 and 70% with dimethyl sulfoxide as the solvent. The results showed that extract of seruni and kembang bulan has a different activity in inhibiting the growth of both fungus. Seruni extract showed lower activity in inhibiting A. flavus and F. moniliforme than kembang bulan. In 40% seruni inhibits the growth both of the fungus. While kembang bulan showed activity in inhibiting A. flavus and F. moniliforme in 5%

Penghambatan Pertumbuhan Aspergillus Flavus dan Fusarium Moniliforme oleh Ekstrak Salam (Eugenia Polyantha) dan Kunyit (Curcuma Domestica)

Growth inhibition of Aspergillus flavus and Fusarium moniliforme by leaf extract of salam (Eugenia polyantha) and turmeric (Curcuma domestica) was studied. Kirby-Bauer disc diffusion method was used in this experiment. The plant extracts used were 0, 5, 10, 15, 30, 40, 50, 60 and 70% and dimethyl sulfoxide (DMSO) as a solvent. The result showed that the E. polyantha and C. domestica have a different activity in inhibiting the growth of A. flavus. The leaf extract of turmeric showed lower activity inhibiting A. flavus and F. moniliforme than that of E.polyantha. In 5% E. polyantha inhibits the growth both of the fungus. While C. domestica showed activity inhibiting A. flavus in 5 % and F. moniliforme in 40 %

Kemampuan Bakteri Endofit Tanaman Semangka Dalam Menekan Perkembangan Penyakit Bercak Daun Yang Disebabkan Oleh Jamur Colletotrichum SP.

Ability of watermelon endophytic bacteria to suppress development of leaf spot disease caused by Colletotrichum sp. A studi on assay of endophytic bacteria to control Colletotrichum sp., causal agent of leaf spot disease on watermelon, was conducted. Colletotrichum sp. was isolated from infected leaf of leaf spot disease, while endophytic bacteria were isolated from stem, leaf, and root of watermelon healthy plant. Antagonistic assay was conducted by dual culture method. Hyphal abnormalities as a result of antagonistic assay was observed using light microscope. To determine the ability of endophytic bacterial isolates to control leaf spot disease, watermelon seeds were treated by dipping the seed in endophytic bacterial suspension. Seven endophytic bacterial isolates showed to inhibit Colletotrichum sp. to some extent. Two isolates DS 01 and BS 01 showed relatively high inhibition zone compared to others, therefore were choosen for further study. Abnormal hyphae such as broken, lysis, twisted, curled, and swollen hyphae were recorded as the result of antagonistic assay. Watermelon seed treatment revealed that dipping the seed in endophytic bacterial suspension of DS 01 and BS 01 reduced leaf spot disease to 12 and 24%, but inhibited seed growth by 12% and 44%, respectively. It seemed that all treatments showed to reduce seedling performance i.e seedling height, leaf number, and dry weight, compared to that of (-) control. DS 01 however seemed to increase dry weight of watermelon plants